Endre søk
Begrens søket
45678910 301 - 350 of 2664
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Treff pr side
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
Merk
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 301.
    Boson, Jonas
    et al.
    Umeå universitet, Medicinsk fakultet, Strålningsvetenskaper, Radiofysik.
    Ågren, Göran
    Johansson, Lennart
    A detailed investigation of HPGe detector response for improved Monte Carlo efficiency calculations2008Inngår i: Nuclear instruments and methods in physics research A, ISSN 0168-9002, Vol. 587, nr 2/3, s. 304-314Artikkel i tidsskrift (Fagfellevurdert)
  • 302. Bossi, A.
    et al.
    Dearnaley, D.
    McKenzie, M.
    Baskin-Bey, E.
    Tyler, R.
    Tombal, B.
    Freedland, S. J.
    Roach, M. , I I I
    Widmark, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Dicker, A. P.
    Wiegel, T.
    Shore, N.
    Smith, M.
    Yu, M.
    Kheoh, T.
    Thomas, S.
    Sandler, H. M.
    ATLAS: A phase 3 trial evaluating the efficacy of apalutamide (ARN-509) in patients with high-risk localized or locally advanced prostate cancer receiving primary radiation therapy2016Inngår i: Annals of Oncology, ISSN 0923-7534, E-ISSN 1569-8041, Vol. 27Artikkel i tidsskrift (Fagfellevurdert)
  • 303. Bottomley, A.
    et al.
    Henriksson, Roger
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Taphoorn, M. J. B.
    Cloughesy, T.
    Wick, W.
    Mason, W.
    Saran, F.
    Nishikawa, R.
    Ravelo, A.
    Chinot, O. L.
    Health-related quality of life (HRQoL) in AVAglio, a randomized, placebo (P)-controlled phase III study of bevacizumab (B), temozolomide (T) and radiotherapy (RI) in patients (pts) with newly diagnosed glioblastoma (GBM)2013Inngår i: European Journal of Cancer, ISSN 0959-8049, E-ISSN 1879-0852, Vol. 49, nr Supplement 2, s. S780-S780, Meeting Abstract: 3316Artikkel i tidsskrift (Annet vitenskapelig)
  • 304.
    Bovinder Ylitalo, Erik
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Nordstrand, Annika
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Thysell, Elin
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Jernberg, Emma
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Crnalic, Sead
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Widmark, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Bergh, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Lerner, Ulf H.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi. Univ Gothenburg, Sahlgrenska Acad, Gothenburg, Sweden.
    Wikström, Pernilla
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Bone remodeling in relation to androgen receptor activity in prostate cancer bone metastases2018Inngår i: Cancer Research, ISSN 0008-5472, E-ISSN 1538-7445, Vol. 78, nr 16, s. 50-50Artikkel i tidsskrift (Annet vitenskapelig)
  • 305.
    Bovinder Ylitalo, Erik
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Thysell, Elin
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Jernberg, Emma
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Lundholm, Marie
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Crnalic, Sead
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Egevad, Lars
    Stattin, Pär
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Urologi och andrologi.
    Widmark, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Bergh, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Wikström, Pernilla
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Subgroups of castration-resistant prostate cancer bone metastases defined through an inverse relationship between androgen receptor activity and immune response2017Inngår i: European Urology, ISSN 0302-2838, E-ISSN 1873-7560, Vol. 71, nr 5, s. 776-787Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background: Novel therapies for men with castration-resistant prostate cancer (CRPC) are needed, particularly for cancers not driven by androgen receptor (AR) activation. Objectives: To identify molecular subgroups of PC bone metastases of relevance for therapy.

    Design, setting, and participants: Fresh-frozen bone metastasis samples from men with CRPC (n = 40), treatment-naïve PC (n = 8), or other malignancies (n = 12) were characterized using whole-genome expression profiling, multivariate principal component analysis (PCA), and functional enrichment analysis. Expression profiles were verified by reverse transcription–polymerase chain reaction (RT-PCR) in an extended set of bone metastases (n = 77) and compared to levels in malignant and adjacent benign prostate tissue from patients with localized disease (n = 12). Selected proteins were evaluated using immunohistochemistry. A cohort of PC patients (n = 284) diagnosed at transurethral resection with long follow-up was used for prognostic evaluation.

    Results and limitations: The majority of CRPC bone metastases (80%) was defined as AR-driven based on PCA analysis and high expression of the AR, AR co-regulators (FOXA1, HOXB13), and AR-regulated genes (KLK2, KLK3, NKX3.1, STEAP2, TMPRSS2); 20% were non–AR-driven. Functional enrichment analysis indicated high metabolic activity and low immune responses in AR-driven metastases. Accordingly, infiltration of CD3+ and CD68+ cells was lower in AR-driven than in non–AR-driven metastases, and tumor cell HLA class I ABC immunoreactivity was inversely correlated with nuclear AR immunoreactivity. RT-PCR analysis showed low MHC class I expression (HLA-A, TAP1, and PSMB9 mRNA) in PC bone metastases compared to benign and malignant prostate tissue and bone metastases of other origins. In primary PC, low HLA class I ABC immunoreactivity was associated with high Gleason score, bone metastasis, and short cancer-specific survival. Limitations include the limited number of patients studied and the single metastasis sample studied per patient.

    Conclusions: Most CRPC bone metastases show high AR and metabolic activities and low immune responses. A subgroup instead shows low AR and metabolic activities, but high immune responses. Targeted therapy for these groups should be explored. Patient summary: We studied heterogeneities at a molecular level in bone metastasis samples obtained from men with castration-resistant prostate cancer. We found differences of possible importance for therapy selection in individual patients.

  • 306.
    Bovinder Ylitalo, Erik
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Thysell, Elin
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Landfors, Mattias
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap.
    Jernberg, Emma
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Crnalic, Sead
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Widmark, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Bergh, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Degerman, Sofie
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Wikström, Pernilla
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Integrated DNA methylation and gene expression analysis of molecular heterogeneity in prostate cancer bone metastasisManuskript (preprint) (Annet vitenskapelig)
  • 307.
    Bovinder Ylitalo, Erik
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Thysell, Elin
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Thellenberg-Karlsson, Camilla
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Lundholm, Marie
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Widmark, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Bergh, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Josefsson, Andreas
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Brattsand, Maria
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Dermatologi och venereologi. Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Wikström, Pernilla
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Excellent cabazitaxel response in prostate cancer xenografts expressing androgen receptor variant 7 and reversion of resistance development by anti-androgensManuskript (preprint) (Annet vitenskapelig)
  • 308. Brandberg, Yvonne
    et al.
    Andersson, Anne
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Bjohle, Judith
    Bosch, Ana
    Carlsson, Lena
    Dreifaldt, Ann Charlotte
    Einbeigi, Zakaria
    Fredholm, Hanna
    Isaksson-Friman, Erika
    Foukakis, Theodoros
    Elinder, Ellinor
    Hellstrom, Mats
    Johansson, Hemming
    Lekberg, Tobias
    Lindman, Henrik
    Bergh, Jonas C. S.
    Hatschek, Thomas
    Health-related quality of life in the Swedish PREDIX HER2 trial, evaluating docetaxel, trastuzumab, pertuzumab versus trastuzumab emtansine as neoadjuvant treatment of HER2-positive breast cancer.2019Inngår i: Journal of Clinical Oncology, ISSN 0732-183X, E-ISSN 1527-7755, Vol. 37, nr 15, s. 583-583Artikkel i tidsskrift (Annet vitenskapelig)
    Abstract [en]

    Background: Neoadjuvant therapy combining docetaxel, trastuzumab and pertuzumab (DTP) was compared to trastuzumab emtansine (T-DM1) in the randomized phase 2 PREDIX HER2 trial. Patients, ≥18 years with HER2 positive breast cancer, ≥20mm or with verified lymph node metastases, were randomized to six courses of DTP (Standard arm) or T-DM1 (Experimental arm). Primary endpoint was pathological objective response to primary medical therapy at post-treatment surgery. Health related quality of life (HRQoL) was a secondary outcome, and is of specific interest as there was no difference between the randomization groups regarding the main endpoint (results presented in a separate abstract sent to ASCO 2019, Bergh et al.). Methods: Of 202 randomized patients, 190 are available for evaluation at this point. HRQoL was measured, using EORTC QLQ-C30 + EORTC QLQ-BR23, at baseline before randomization and after six courses. Results: No differences between the randomization arms were found at baseline. Results after six courses, based on 163 patients (86%) and adjusted to baseline values, revealed statistical significant differences (p≤0.01), favoring the experimental T-DM1 arm on 7 out of 15 of the EORTC QLQ-C30 variables (Physical functioning, Role functioning, Social functioning, Global quality of Life, Fatigue, Dyspnea, and Diarrhea). For the breast cancer specific questionnaire (EORTC-BR23), the experimental arm scored statistically significantly better on 5 out of 7 subscales (Body image, Sexual functioning, Sexual enjoyment, Systemic therapy side effects and Upset by hair loss). All of the statistical significant differences were of moderate or large clinical significance (≥10 scale scores). No differences between the randomization arms were found for the remaining HRQoL variables. Conclusions: The experimental arm reported better HRQoL than the control arm after six courses. Trastuzumab emtansine may be a useful treatment alternative due to better HRQoL and lower toxicity. Clinical trial information: NCT02568839.

  • 309. Brandefors, Lena
    et al.
    Kimby, Eva
    Lundqvist, Kristina
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Melin, Beatrice
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Lindh, Jack
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Familial Waldenstrom's macroglobulinemia and relation to immune defects, autoimmune diseases, and haematological malignancies: a population-based study from northern Sweden2016Inngår i: Acta Oncologica, ISSN 0284-186X, E-ISSN 1651-226X, Vol. 55, nr 1, s. 91-98Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background: Waldenstrom's macroglobulinemia (WM) is a rare lymphoprolipherative disorder with geographic and ethnic disparities in incidence. The cause of WM remains mostly unknown although a role for genetic, immune-related, and environmental factors has been suggested. Most cases of WM are sporadic although familial cases occur. Aim: This study estimated the incidence of WM in northern Sweden and identified and described patients with familial WM in this area. Patients and methods: The Swedish and Northern Lymphoma Registry, the Swedish Cancer Registry (1997-2011), and medical records were used to identify patients with WM in two counties (Norrbotten and Västerbotten) in northern Sweden and to calculate the overall age-adjusted incidence (2000-2012). We identified 12 families with a family history of WM, IgM monoclonal gammophathy (MGUS), and/or multiple myeloma (MM). Results: In Norrbotten and Västerbotten, the age-adjusted incidence of WM/LPL is 1.75 and 1.48 per 100 000 persons per year, respectively (2000-2012), rates that are higher than the overall incidence of WM/LPL in Sweden (1.05 per 100 000 persons per year; 2000-2012). Autoimmune diseases and other haematological malignancies in the medical history (their own or in relatives) were reported in 9/12 and 5/12 families, respectively. A high proportion of abnormal serum protein electrophoresis was found in the relatives; 12/56 (21%) had a MGUS and 13/56 (25%) showed abnormalities in the immunoglobulin levels (i.e. subnormal levels and poly/oligoclonality). Conclusion: The incidence of WM in Norrbotten and Västerbotten counties was higher than expected. We found a strong correlation between autoimmune/inflammatory diseases, other haematological malignancies, and familial WM and a high frequency of serum immunoglobulin abnormalities in the relatives of the WM patients, findings that strengthen the hypothesis that the aetiology of WM depends on both immune-related and genetic factors.

  • 310.
    Brandefors, Lena
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi. Sunderby Research Unit.
    Lindh, Jack
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi. Sunderby Research Unit.
    Preuss, Klaus-Dieter
    Fadle, Natalie
    Pfreundschuh, Michael
    Kimby, Eva
    Incidence and inheritance of hyperphosphorylated paratarg-7 in patients with Waldenstrom's macroglobulinaemia in Sweden2019Inngår i: Acta Oncologica, ISSN 0284-186X, E-ISSN 1651-226X, Vol. 58, nr 6, s. 824-827Artikkel i tidsskrift (Fagfellevurdert)
  • 311. Brandefors, Lena
    et al.
    Melin, Beatrice S.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Lindh, Jack
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Lundqvist, Kristina
    Kimby, Eva
    Prognostic factors and primary treatment for Waldenstrom macroglobulinemia: a Swedish Lymphoma Registry study2018Inngår i: British Journal of Haematology, ISSN 0007-1048, E-ISSN 1365-2141, Vol. 183, nr 4, s. 564-577Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present a nationwide prospective Swedish registry-based study of Waldenstrom macroglobulinaemia (WM), that focuses on incidence and survival in relation to clinical prognostic factors and primary systemic therapies. A total of 1511 patients with WM and lymphoplasmocytic lymphoma (LPL) were registered in the Swedish Lymphoma Registry (SLR) between 1 January 2000 and 31 December 2014. The age-adjusted incidence of WM/LPL was 11.5 per million persons per year, three times higher than the reported incidence worldwide. Medical records were retrieved for 1135 patients (75%). A retrospective review showed that 981 (86.1%) of these patients fulfilled the World Health Organization diagnostic criteria for WM and these patients were analysed further. The overall survival (OS) improved between two periods - 2000-2006 and 2007-2014 - with a five-year OS of 61% and 70%, respectively. Significant prognostic factors for OS, evaluated at the time of diagnosis, were age, elevated lactate dehydrogenase level and haemoglobin <= 115 g/l for patients receiving therapy 0-3 months after diagnosis, and age, poor performance status, haemoglobin <= 115 g/l, and female sex in "watch and wait" patients (multivariable analysis). The level of the IgM monoclonal immunoglobulin had no significant prognostic value. Rituximab included in first-line therapy was associated with improved survival.

  • 312.
    Brandel, Jens
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Diagnostisk radiologi.
    Evaluation of 18F-fluorothymidine PET/MRI imaging in treated glioblastoma patients2018Independent thesis Basic level (professional degree), 20 poäng / 30 hpOppgave
  • 313.
    Brantefors, Per
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper. Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik. Karolinska Institutet, Department of Clinical Neuroscience.
    Dynamic fMRI brain connectivity: A study of the brain’s large-scale network dynamics2016Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Approximately 20% of the body’s energy consumption is ongoingly consumed by the brain, where the main part is due to the neural activity, which is only increased slightly when doing a demanding task. This ongoingly neural activity are studied with the so called resting-state fMRI, which mean that the neural activity in the brain is measured for participants with no specific task. These studies have been useful to understand the neural function and how the neural networks are constructed and cooperate. This have also been helpful in several clinical research, for example have differences been identified between bipolar disorder and major depressive disorder. Recent research has focused on temporal properties of the ongoing activity and it is well known that neural activity occurs in bursts. In this study, resting-state fMRI data and temporal graph theory is used to develop a point based method (PBM) to quantify these bursts at a nodal level. By doing this, the bursty pattern can be further investigated and the nodes showing the most bursty pattern (i.e hubs) can be identified. The method developed shows a robustness regarding several different aspects. In the method is two different variance threshold algorithms suggested. One local variance threshold (LVT) based on the individual variance of the edge time-series and one global variance threshold (GVT) based on the variance of all edges time-series, where the GVT shows the highest robustness. However, the choice of threshold needs to be adapted for the aims of the current study. Finally, this method ends up in a new measure to quantify this bursty pattern named bursty centrality. The derived temporal graph theoretical measure was correlated with traditional static graph properties used in resting state and showed a low but significant correlation. By applying this method on resting-state fMRI data for 32 young adults was it possible to identify regions of the brain that showed the most dynamic properties, these regions differed between the two thresholding algorithms

  • 314. Brendle, Annika
    et al.
    Brandt, Andreas
    Johansson, Robert
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Enquist, Kerstin
    Hallmans, Göran
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Näringsforskning.
    Hemminki, Kari
    Lenner, Per
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Försti, Asta
    Single nucleotide polymorphisms in chromosomal instability genes and risk and clinical outcome of breast cancer: a Swedish prospective case-control study.2009Inngår i: European journal of cancer (Oxford, England : 1990), ISSN 1879-0852, Vol. 45, nr 3, s. 435-442Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Chromosomal instability (CIN) is a major characteristic of many cancers. We investigated whether putatively functional single nucleotide polymorphisms (SNPs) in genes related to CIN (CENPF, ESPL1, NEK2, PTTG1, ZWILCH, ZWINT) affect breast cancer (BC) risk and clinical outcome in a Swedish cohort of 749 incident BC cases with detailed clinical data and up to 15 years of follow-up and 1493 matched controls. As a main observation, carriers of the A allele of the CENPF SNP rs438034 had a worse BC-specific survival compared to the wild type genotype GG carriers (hazard ratio (HR) 2.65, 95% confidence interval (CI) 1.19-5.90), although they were less likely to have regional lymph node metastases (odds ratio (OR) 0.71, 95% CI 0.51-1.01) and tumours of stage II-IV (OR 0.73, 95% CI 0.54-0.99). As there is increasing evidence that CENPF is associated with poor prognosis in patients with primary BC, further independent studies are needed to clarify the importance of genetic variation in the CENPF gene in the clinic.

  • 315. Brendle, Annika
    et al.
    Lei, Haixin
    Brandt, Andreas
    Johansson, Robert
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Enquist, Kerstin
    Henriksson, Roger
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Hemminki, Kari
    Lenner, Per
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Försti, Asta
    Polymorphisms in predicted microRNA-binding sites in integrin genes and breast cancer ITGB4 as prognostic marker.2008Inngår i: Carcinogenesis, ISSN 1460-2180, Vol. 29, nr 7, s. 1394-1399Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Integrins control the cell attachment to the extracellular matrix and play an important role in mediating cell proliferation, migration and survival. A number of important cancer-associated integrin genes can be regulated by microRNAs (miRNAs) that bind to their target sites in the 3' untranslated regions. We examined the effect of single-nucleotide polymorphisms (SNPs) in predicted miRNA target sites of six integrin genes (ITGA3, ITGA6, ITGAv, ITGB3, ITGB4 and ITGB5) on breast cancer (BC) risk and clinical outcome. Six SNPs were genotyped in 749 Swedish incident BC cases with detailed clinical data and up to 15 years of follow-up together with 1493 matched controls. We evaluated associations between genotypes and BC risk and clinical tumour characteristics. Survival probabilities were compared between different subgroups. As a novel finding, several SNPs seemed to associate with the hormone receptor status. The strongest association was observed between the A allele of the SNP rs743554 in the ITGB4 gene and oestrogen receptor-negative tumours [odds ratio 2.09, 95% confidence intervals (CIs) 1.19-3.67]. The same SNP was associated with survival. The A allele carriers had a worse survival compared with the wild-type genotype carriers (hazard ratio 2.11, 95% CIs 1.21-3.68). The poor survival was significantly associated with the aggressive tumour characteristics: high grade, lymph node metastasis and high stage. None of the SNPs was significantly associated with BC risk. As the ITGB4 SNP seems to influence tumour aggressiveness and survival, it may have prognostic value in the clinic.

  • 316. Brenner, Darren R.
    et al.
    Fanidi, Anouar
    Grankvist, Kjell
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap.
    Muller, David C.
    Brennan, Paul
    Manjer, Jonas
    Byrnes, Graham
    Hodge, Allison
    Severi, Gianluca
    Giles, Graham G.
    Johansson, Mikael
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Johansson, Mattias
    Inflammatory Cytokines and Lung Cancer Risk in 3 Prospective Studies2017Inngår i: American Journal of Epidemiology, ISSN 0002-9262, E-ISSN 1476-6256, Vol. 185, nr 2, s. 86-95Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    To further investigate the role of inflammation in lung carcinogenesis, we evaluated associations between proinflammatory cytokines and lung cancer risk. We conducted a case-control study nested within 3 prospective cohort studies-the Melbourne Collaborative Cohort Study (1990-1994), the Malm Diet and Cancer Study (1991-1996), and the Northern Sweden Health and Disease Study (initiated in 1985)-involving 807 incident lung cancer cases and 807 smoking-matched controls. Conditional logistic regression models adjusting for serum cotinine concentrations were used to estimate odds ratios for lung cancer risk associated with concentrations of interleukin (IL)-1 beta, IL-2, IL-6, IL-8, IL-10, IL-12, interferon., tumor necrosis factor a, and granulocyte-macrophage colony-stimulating factor. We observed a higher lung cancer risk for participants with elevated concentrations of IL-6 and IL-8. These associations seemed to be stronger among former smokers (for fourth quartile vs. first quartile, odds ratio (OR) = 2.70, 95% confidence interval (CI): 1.55, 4.70) and current smokers (OR = 1.99, 95% CI: 1.15, 3.44) for IL-6 and among former smokers (OR = 2.83, 95% CI: 1.18, 6.75) and current smokers (OR = 1.30, 95% CI: 0.69, 2.44) for IL-8. No notable associations were observed among never smokers. Risk associations with IL-6 and IL-8 were observed for blood samples taken close to diagnosis (< 5 years) as well as more than 15 years postdiagnosis.

  • 317. Breugom, A. J.
    et al.
    Bastiaannet, E.
    Boelens, P. G.
    Iversen, L. H.
    Martling, A.
    Johansson, R.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Evans, T.
    Lawton, S.
    O'Brien, K. M.
    Van Eycken, E.
    Janciauskiene, R.
    Liefers, G. J.
    Cervantes, A.
    Lemmens, V. E. P. P.
    van de Velde, C. J. H.
    Adjuvant chemotherapy and relative survival of patients with stage II colon cancer - A EURECCA international comparison between the Netherlands, Denmark, Sweden, England, Ireland, Belgium, and Lithuania2016Inngår i: European Journal of Cancer, ISSN 0959-8049, E-ISSN 1879-0852, Vol. 63, s. 110-117Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background: The aim of the present EURECCA international comparison is to compare adjuvant chemotherapy and relative survival of patients with stage II colon cancer between European countries.

    Methods: Population-based national cohort data (2004-2009) from the Netherlands (NL), Denmark (DK), Sweden (SE), England (ENG), Ireland (IE), and Belgium (BE) were obtained, as well as single-centre data from Lithuania. All surgically treated patients with stage II colon cancer were included. The proportion of patients receiving adjuvant chemotherapy was calculated and compared between countries. Besides, relative survival was calculated and compared between countries.

    Results: Overall, 59,154 patients were included. The proportion of patients receiving adjuvant chemotherapy ranged from 7.1% to 29.0% (p < 0.001). Compared with NL, a better adjusted relative survival was observed in SE (stage II: relative excess risks (RER) 0.53, 95% confidence interval (CI) 0.44-0.64; p < 0.001), and BE (stage II: RER 0.84, 95% CI 0.76-0.92; p < 0.001), and in IE for patients with stage IIA disease (RER 0.80, 95% CI 0.65-0.98; p = 0.03).

    Conclusion: The proportion of patients with stage II colon cancer receiving adjuvant chemotherapy varied largely between seven European countries. No clear linear pattern between adjuvant chemotherapy and adjusted relative survival was observed. Compared with NL, SE and BE showed an improved adjusted relative survival for stage II disease, and IE for patients with stage IIA disease only. Further research into selection criteria for adjuvant chemotherapy could eventually lead to individually tailored, optimal treatment of patients with stage II colon cancer.

  • 318. Breugom, A. J.
    et al.
    Bastiaannet, E.
    Boelens, P. G.
    Van Eycken, E.
    Iversen, L. H.
    Martling, A.
    Johansson, Robert
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Evans, T.
    Lawton, S.
    O'Brien, K. M.
    Ortiz, H.
    Janciauskiene, R.
    Dekkers, O. M.
    Rutten, H. J. T.
    Liefers, G. J.
    Lemmens, V. E. P. P.
    van de Velde, C. J. H.
    Oncologic treatment strategies and relative survival of patients with stage I-III rectal cancer - A EURECCA international comparison between the Netherlands, Belgium, Denmark, Sweden, England, Ireland, Spain, and Lithuania2018Inngår i: European Journal of Surgical Oncology, ISSN 0748-7983, E-ISSN 1532-2157, Vol. 44, nr 9, s. 1338-1343Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Introduction: The aim of this EURECCA international comparison is to compare oncologic treatment strategies and relative survival of patients with stage I-III rectal cancer between European countries.

    Material and methods: Population-based national cohort data from the Netherlands (NL), Belgium (BE), Denmark (DK), Sweden (SE), England (ENG), Ireland (IE), Spain (ES), and single-centre data from Lithuania (LT) were obtained. All operated patients with (y)pTNM stage I-III rectal cancer diagnosed between 2004 and 2009 were included. Oncologic treatment strategies and relative survival were calculated and compared between neighbouring countries.

    Results: We included 57,120 patients. Treatment strategies differed between NL and BE (p < 0.001), DK and SE (p < 0.001), and ENG and IE (p < 0.001). More preoperative radiotherapy as single treatment before surgery was administered in NL compared with BE (59.7% vs. 13.1%), in SE compared with DK (55.1% vs. 10.4%), and in ENG compared with IE (15.2% vs. 9.6%). Less postoperative chemotherapy was given in NL (9.6% vs. 39.1%), in SE (7.9% vs. 14.1%), and in IE (12.6% vs. 18.5%) compared with their neighbouring country. In ES, 55.1% of patients received preoperative chemoradiation and 62.3% post-operative chemotherapy. There were no significant differences in relative survival between neighbouring countries.

    Conclusion: Large differences in oncologic treatment strategies for patients with (y)pTNM I-III rectal cancer were observed across European countries. No clear relation between oncologic treatment strategies and relative survival was observed. Further research into selection criteria for specific treatments could eventually lead to individualised and optimal treatment for patients with non-metastasised rectal cancer. 

  • 319.
    Britta, Lindström
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för samhällsmedicin och rehabilitering, Sjukgymnastik.
    Karlsson, Stefan
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Lexell, Jan
    Isokinetic torque and surface electromyography during fatiguing muscle contractions in young and older men and women.2006Inngår i: Isokinetics and Exercise Science, ISSN 0959-3020, Vol. 14, s. 225-234Artikkel i tidsskrift (Fagfellevurdert)
  • 320. Britton, Julie A
    et al.
    Khan, Aneire E
    Rohrmann, Sabine
    Becker, Nikolaus
    Linseisen, Jakob
    Nieters, Alexandra
    Kaaks, Rudolf
    Tjønneland, Anne
    Halkjaer, Jytte
    Severinsen, Marianne Tang
    Overvad, Kim
    Pischon, Tobias
    Boeing, Heiner
    Trichopoulou, Antonia
    Kalapothaki, Victoria
    Trichopoulos, Dimitrios
    Mattiello, Amalia
    Tagliabue, Giovanna
    Sacerdote, Carlotta
    Peeters, Petra H M
    Bueno-de-Mesquita, H Bas
    Ardanaz, Eva
    Navarro, Carmen
    Jakszyn, Paula
    Altzibar, Jone M
    Hallmans, Göran
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Näringsforskning.
    Malmer, Beatrice
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Berglund, Göran
    Manjer, Jonas
    Allen, Naomi
    Key, Timothy
    Bingham, Sheila
    Besson, Hervé
    Ferrari, Pietro
    Jenab, Mazda
    Boffetta, Paolo
    Vineis, Paolo
    Riboli, Elio
    Anthropometric characteristics and non-Hodgkin's lymphoma and multiple myeloma risk in the European Prospective Investigation into Cancer and Nutrition (EPIC).2008Inngår i: Haematologica, ISSN 1592-8721, Vol. 93, nr 11, s. 1666-1677Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    BACKGROUND:

    The incidences of non-Hodgkin's lymphoma and multiple myeloma are increasing steadily. It has been hypothesized that this may be due, in part, to the parallel rising prevalence of obesity. It is biologically plausible that anthropometric characteristics can infuence the risk of non-Hodgkin's lymphoma and multiple myeloma.

    DESIGN AND METHODS:

    In the context of the European Prospective Investigation into Cancer and Nutrition (EPIC), anthropometric characteristics were assessed in 371,983 cancer-free individuals at baseline. During the 8.5 years of follow-up, 1,219 histologically confirmed incident cases of non-Hodgkin's lymphoma and multiple myeloma occurred in 609 men and 610 women. Gender-specific proportional hazards models were used to estimate relative risks and 95% confidence intervals (95% CI) of development of non-Hodgkin's lymphoma and multiple myeloma in relation to the anthropometric characteristics.

    RESULTS:

    Height was associated with overall non-Hodgkin's lymphoma and multiple myeloma in women (RR 1.50, 95% CI 1.14-1.98) for highest versus lowest quartile; p-trend < 0.01) but not in men. Neither obesity (weight and body mass index) nor abdominal fat (waist-to-hip ratio, waist or hip circumference) measures were positively associated with overall non-Hodgkin's lymphoma and multiple myeloma. Relative risks for highest versus lowest body mass index quartile were 1.09 (95% CI 0.85-1.38) and 0.92 (95% CI 0.71-1.19) for men and women, respectively. Women in the upper body mass index quartile were at greater risk of diffuse large B-cell lymphoma (RR 2.18, 95% CI 1.05-4.53) and taller women had an elevated risk of follicular lymphoma (RR 1.25, 95% CI 0.59-2.62). Among men, height and body mass index were non-significantly, positively related to follicular lymphoma. Multiple myeloma risk alone was elevated for taller women (RR 2.34, 95% CI 1.29-4.21) and heavier men (RR 1.77, 95% CI 1.02-3.05).

    CONCLUSIONS:

    The EPIC analyses support an association between height and overall non-Hodgkin's lymphoma and multiple myeloma among women and suggest heterogeneous subtype associations. This is one of the first prospective studies focusing on central adiposity and non-Hodgkin's lymphoma subtypes.

  • 321. Broeders, Mireille
    et al.
    Moss, Sue
    Nyström, Lennarth
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin.
    Njor, Sisse
    Jonsson, Håkan
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Poop, Ellen
    Massat, Nathalie
    Duffy, Stephen
    Lynge, Elsebeth
    Paci, Eugenio
    The impact of mammographic screening on breast cancer mortality in Europe: a review of observational studies2012Inngår i: Journal of Medical Screening, ISSN 0969-1413, E-ISSN 1475-5793, Vol. 19, s. 14-25Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Objectives To assess the impact of population-based mammographic screening on breast cancer mortality in Europe, considering different methodologies and limitations of the data. Methods We conducted a systematic literature review of European trend studies (n = 17), incidence-based mortality (IBM) studies (n = 20) and case-control (CC) studies (n = 8). Estimates of the reduction in breast cancer mortality for women invited versus not invited and/or for women screened versus not screened were obtained. The results of IBM studies and CC studies were each pooled using a random effects meta-analysis. Results Twelve of the 17 trend studies quantified the impact of population-based screening on breast cancer mortality. The estimated breast cancer mortality reductions ranged from 1% to 9% per year in studies reporting an annual percentage change, and from 28% to 36% in those comparing post- and prescreening periods. In the IBM studies, the pooled mortality reduction was 25% (relative risk [RR] 0.75, 95% confidence interval [CI] 0.69-0.81) among invited women and 38% (RR 0.62, 95% CI 0.56-0.69) among those actually screened. The corresponding pooled estimates from the CC studies were 31% (odds ratio [OR] 0.69, 95% CI 0.57-0.83), and 48% (OR 0.52, 95% CI 0.42-0.65) adjusted for self-selection. Conclusions Valid observational designs are those where sufficient longitudinal individual data are available, directly linking a woman's screening history to her cause of death. From such studies, the best 'European' estimate of breast cancer mortality reduction is 25-31% for women invited for screening, and 38-48% for women actually screened. Much of the current controversy on breast cancer screening is due to the use of inappropriate methodological approaches that are unable to capture the true effect of mammographic screening.

  • 322. Brolin, Gustav
    et al.
    Edenbrandt, Lars
    Granerus, Goeran
    Olsson, Anna
    Afzelius, David
    Gustafsson, Agneta
    Jonsson, Cathrine
    Hagerman, Jessica
    Johansson, Lena
    Riklund, Katrine
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Diagnostisk radiologi. EQUALIS AB, Uppsala, Sweden.
    Ljungberg, Michael
    The accuracy of quantitative parameters in Tc-99m-MAG3 dynamic renography: a national audit based on virtual image data2016Inngår i: Clinical Physiology and Functional Imaging, ISSN 1475-0961, E-ISSN 1475-097X, Vol. 36, nr 2, s. 146-154Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Assessment of image analysis methods and computer software used in Tc-99m-MAG3 dynamic renography is important to ensure reliable study results and ultimately the best possible care for patients. In this work, we present a national multicentre study of the quantification accuracy in Tc-99m-MAG3 renography, utilizing virtual dynamic scintigraphic data obtained by Monte Carlo-simulated scintillation camera imaging of digital phantoms with time-varying activity distributions. Three digital phantom studies were distributed to the participating departments, and quantitative evaluation was performed with standard clinical software according to local routines. The differential renal function (DRF) and time to maximum renal activity (T-max) were reported by 21 of the 28 Swedish departments performing Tc-99m-MAG3 studies as of 2012. The reported DRF estimates showed a significantly lower precision for the phantom with impaired renal uptake than for the phantom with normal uptake. The T-max estimates showed a similar trend, but the difference was only significant for the right kidney. There was a significant bias in the measured DRF for all phantoms caused by different positions of the left and right kidney in the anterior-posterior direction. In conclusion, this study shows that virtual scintigraphic studies are applicable for quality assurance and that there is a considerable uncertainty associated with standard quantitative parameters in dynamic Tc-99m-MAG3 renography, especially for patients with impaired renal function.

  • 323.
    Bromée, Emil
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Pilot study for the REPAC study: This study is a pilot study for the larger REPAC (Rehabilitation of Patients receiving Adjuvant Chemotherapy) study2016Independent thesis Basic level (degree of Bachelor of Fine Arts), 20 poäng / 30 hpOppgave
  • 324. Brown, David A
    et al.
    Lindmark, Fredrik
    Umeå universitet, Medicinsk fakultet, Strålningsvetenskaper.
    Stattin, Pär
    Umeå universitet, Medicinsk fakultet, Kirurgisk och perioperativ vetenskap, Urologi och andrologi.
    Bälter, Katarina
    Adami, Hans-Olov
    Zheng, Sigun L
    Xu, Jianfeng
    Isaacs, William B
    Grönberg, Henrik
    Breit, Samuel N
    Wiklund, Fredrik E
    Macrophage inhibitory cytokine 1: a new prognostic marker in prostate cancer.2009Inngår i: Clinical Cancer Research, ISSN 1078-0432, E-ISSN 1557-3265, Vol. 15, nr 21, s. 6658-6664Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    PURPOSE: High serum levels of macrophage inhibitory cytokine 1 (MIC-1) are strongly associated with metastatic prostate cancer, suggesting MIC-1 is a biomarker for prostate cancer prognosis. EXPERIMENTAL DESIGN: We conducted a prospective cohort study of 1,442 Swedish men with a pathologically verified diagnosis of prostate cancer between 2001 and 2003. Blood was drawn either pretreatment (n = 431) or posttreatment (n = 1,011) and cases were followed for a mean time of 4.9 years (range, 0.1-6.8 years). RESULTS: MIC-1 serum levels independently predicted poor cancer-specific survival with an almost 3-fold higher cancer death rate in patients with serum levels in the highest quartile compared with men with serum levels in the lowest quartile (adjusted hazard ratio, 2.98; 95% confidence interval, 1.82-4.68). Pretreatment MIC-1 levels revealed an even stronger association with disease outcome with an 8-fold higher death rate in the highest compared with the lowest category (adjusted hazard ratio, 7.98; 95% confidence interval, 1.73-36.86). Among patients considered to have localized disease, MIC-1 significantly increased the discriminative capacity between indolent and lethal prostate cancer compared with the established prognostic markers clinical stage, pathologic grade, and prostate-specific antigen level (P = 0.016). A sequence variant in the MIC-1 gene was associated with decreased MIC-1 serum levels (P = 0.002) and decreased prostate cancer mortality (P = 0.003), suggesting a causative role of MIC-1 in prostate cancer prognosis. CONCLUSIONS: Serum MIC-1 concentration is a novel biomarker capable of predicting prostate cancer prognosis.

  • 325.
    Brynolfsson, Patrik
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Applications of statistical methods in quantitative magnetic resonance imaging2017Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Magnetic resonance imaging, MRI, offers a vast range of imaging methods that can be employed in the characterization of tumors. MRI is generally used in a qualitative way, where radiologists interpret the images for e.g. diagnosis, follow ups, or assessment of treatment response. In the past decade, there has been an increasing interest for quantitative imaging, which give repeatable measurements of the anatomy. Quantitative imaging allows for objective analysis of the images, which are grounded in physical properties of the underlying tissues. The aim of this thesis was to improve quantitative measurements of Dynamic contrast enhanced MRI (DCE-MRI), and the texture analysis of diffusion weighted MRI (DW-MRI).

    DCE-MRI measures perfusion, which is the delivery of blood, oxygen and nutrients to the tissues. The exam involves continuously imaging the region of interest, e.g. a tumor, while injecting a contrast agent (CA) in the blood stream. By analyzing how fast and how much CA leaks out into the tissues, the cell density and the permeability of the capillaries can be estimated. Tumors often have an irregular and broken vasculature, and DCE-MRI can aid in tumor grading or treatment assessment. One step is crucial when performing DCE-MRI analysis, the quantification of CA in the tissue. The CA concentration is difficult to measure accurately due to uncertainties in the imaging, properties of the CA, and physiology of the patient. Paper I, the possibility of using two aspects of the MRI data, phase and magnitude, for improved CA quantification, is explored. We found that the combination of phase and magnitude information improved the CA quantification in regions with high CA concentration, and was more advantageous for high field strength scanners.

    DW-MRI measures the diffusion of water in and between cells, which reflects the cell density and structure of the tissue. The structure of a tumor can give insights into the prognosis of the disease. Tumors are heterogeneous, both genetically and in the distribution of cells, and tumors with high intratumoral heterogeneity have poorer prognosis. This heterogeneity can be measured using texture analysis. In 1973, Haralick et al. presented a texture analysis method using a gray level co-occurrence matrix, GLCM, to gauge the spatial distribution of gray levels in the image. This method of assessing texture in images has been successfully applied in many areas of research, from satellite images to medical applications. Texture analysis in treatment outcome assessment is studied in Paper II, where we showed that texture can distinguish between groups of patients with different survival times, in images acquired prior to treatment start.

    However, this type of texture analysis is not inherently quantitative in the way it is calculated today. This was studied in Paper III, where we investigated how texture features were affected by five parameters related to image acquisition and pre-processing. We found that the texture feature values were dependent on the choice of these imaging and preprocessing parameters. In Paper IV, a novel method for calculating Haralick texture features was presented, which makes the texture features asymptotically invariant to the size of the GLCM. This method allows for comparison of textures between images that have been analyzed in different ways.

    In conclusion, the work in this thesis has been aimed at improving quantitative analysis of tumors using MRI and texture analysis.

  • 326.
    Brynolfsson, Patrik
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Using radial k-space sampling and temporal filters in MRI to improve temporal resolution2010Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    In this master thesis methods for increasing temporal resolution when reconstructing radially sampled MRI data have been developed and evaluated. This has been done in two steps; first the order in which data is sampled in k-space has been optimized, and second; temporal filters have been developed in order to utilize the high sampling density in central regions of k-space as a result of the polar sampling geometry to increase temporal resolution while maintaining image quality.By properly designing the temporal filters the temporal resolution is increased by a factor 3–20 depending on other variables such as imageresolution and the size of the time varying areas in the image. The results are obtained from simulated raw data and subsequent reconstruction. The next step should be to acquire and reconstruct raw data to confirm the results.

  • 327.
    Brynolfsson, Patrik
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Axelsson, Jan
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Holmberg, August
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Jonsson, Joakim
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Goldhaber, David
    Jian, Yiqiang
    Illerstam, Fredrik
    Engström, Mathias
    Zackrisson, Björn
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Nyholm, Tufve
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Technical note: adapting a GE SIGNA PET/MR scanner for radiotherapy2018Inngår i: Medical physics (Lancaster), ISSN 0094-2405, Vol. 45, nr 8, s. 3546-3550Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Purpose: Simultaneous collection of PET and MR data for radiotherapy purposes are useful for, for example, target definition and dose escalations. However, a prerequisite for using PET/MR in the radiotherapy workflow is the ability to image the patient in treatment position. The aim of this work was to adapt a GE SIGNA PET/MR scanner to image patients for radiotherapy treatment planning and evaluate the impact on signal-to-noise (SNR) of the MR images, and the accuracy of the PET attenuation correction. Method: A flat tabletop and a coil holder were developed to image patients in the treatment position, avoid patient contour deformation, and facilitate attenuation correction of flex coils. Attenuation corrections for the developed hardware and an anterior array flex coil were also measured and implemented to the PET/MR system to minimize PET quantitation errors. The reduction of SNR in the MR images due to the added distance between the coils and the patient was evaluated using a large homogenous saline-doped water phantom, and the activity quantitation errors in PET imaging were evaluated with and without the developed attenuation corrections. Result: We showed that the activity quantitation errors in PET imaging were within ±5% when correcting for attenuation of the flat tabletop, coil holder, and flex coil. The SNR of the MRI images were reduced to 74% using the tabletop, and 66% using the tabletop and coil holders. Conclusion: We present a tabletop and coil holder for an anterior array coil to be used with a GE SIGNA PET/MR scanner, for scanning patients in the radiotherapy work flow. Implementing attenuation correction of the added hardware from the radiotherapy setup leads to acceptable PET image quantitation. The drop in SNR in MR images may require adjustment of the imaging protocols.

  • 328.
    Brynolfsson, Patrik
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Löfstedt, Tommy
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Asklund, Thomas
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Nyholm, Tufve
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Garpebring, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Gray-level invariant Haralick texture features2018Inngår i: Radiotherapy and Oncology, ISSN 0167-8140, E-ISSN 1879-0887, Vol. 127, s. S279-S280Artikkel i tidsskrift (Annet vitenskapelig)
  • 329.
    Brynolfsson, Patrik
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Nilsson, David
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Henriksson, Roger
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Hauksson, Jon
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Karlsson, Mikael
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Garpebring, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Birgander, Richard
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Trygg, Johan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Nyholm, Tufve
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Asklund, Thomas
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    ADC texture-An imaging biomarker for high-grade glioma?2014Inngår i: Medical physics (Lancaster), ISSN 0094-2405, Vol. 41, nr 10, s. 101903-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Purpose:

    Survival for high-grade gliomas is poor, at least partly explained by intratumoral heterogeneity contributing to treatment resistance. Radiological evaluation of treatment response is in most cases limited to assessment of tumor size months after the initiation of therapy. Diffusion-weighted magnetic resonance imaging (MRI) and its estimate of the apparent diffusion coefficient (ADC) has been widely investigated, as it reflects tumor cellularity and proliferation. The aim of this study was to investigate texture analysis of ADC images in conjunction with multivariate image analysis as a means for identification of pretreatment imaging biomarkers.

    Methods:

    Twenty-three consecutive high-grade glioma patients were treated with radiotherapy (2 Gy/60 Gy) with concomitant and adjuvant temozolomide. ADC maps and T1-weighted anatomical images with and without contrast enhancement were collected prior to treatment, and (residual) tumor contrast enhancement was delineated. A gray-level co-occurrence matrix analysis was performed on the ADC maps in a cuboid encapsulating the tumor in coronal, sagittal, and transversal planes, giving a total of 60 textural descriptors for each tumor. In addition, similar examinations and analyses were performed at day 1, week 2, and week 6 into treatment. Principal component analysis (PCA) was applied to reduce dimensionality of the data, and the five largest components (scores) were used in subsequent analyses. MRI assessment three months after completion of radiochemotherapy was used for classifying tumor progression or regression.

    Results:

    The score scatter plots revealed that the first, third, and fifth components of the pretreatment examinations exhibited a pattern that strongly correlated to survival. Two groups could be identified: one with a median survival after diagnosis of 1099 days and one with 345 days, p = 0.0001.

    Conclusions:

    By combining PCA and texture analysis, ADC texture characteristics were identified, which seems to hold pretreatment prognostic information, independent of known prognostic factors such as age, stage, and surgical procedure. These findings encourage further studies with a larger patient cohort. (C) 2014 Author(s).

  • 330.
    Brynolfsson, Patrik
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Nilsson, David
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Torheim, Turid
    Asklund, Thomas
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Thellenberg Karlsson, Camilla
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Trygg, Johan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Nyholm, Tufve
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Garpebring, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Haralick texture features from apparent diffusion coefficient (ADC) MRI images depend on imaging and pre-processing parameters2017Inngår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, artikkel-id 4041Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In recent years, texture analysis of medical images has become increasingly popular in studies investigating diagnosis, classification and treatment response assessment of cancerous disease. Despite numerous applications in oncology and medical imaging in general, there is no consensus regarding texture analysis workflow, or reporting of parameter settings crucial for replication of results. The aim of this study was to assess how sensitive Haralick texture features of apparent diffusion coefficient (ADC) MR images are to changes in five parameters related to image acquisition and pre-processing: noise, resolution, how the ADC map is constructed, the choice of quantization method, and the number of gray levels in the quantized image. We found that noise, resolution, choice of quantization method and the number of gray levels in the quantized images had a significant influence on most texture features, and that the effect size varied between different features. Different methods for constructing the ADC maps did not have an impact on any texture feature. Based on our results, we recommend using images with similar resolutions and noise levels, using one quantization method, and the same number of gray levels in all quantized images, to make meaningful comparisons of texture feature results between different subjects.

  • 331.
    Brynolfsson, Patrik
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Yu, Jun
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för matematik och matematisk statistik.
    Wirestam, Ronnie
    Lund University.
    Karlsson, Mikael
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Garpebring, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper. CJ Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, Netherlands.
    Combining phase and magnitude information for contrast agent quantification in dynamic contrast-enhanced MRI using statistical modeling2015Inngår i: Magnetic Resonance in Medicine, ISSN 0740-3194, E-ISSN 1522-2594, Vol. 74, nr 4, s. 1156-1164Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Purpose: The purpose of this study was to investigate, using simulations, a method for improved contrast agent (CA) quantification in DCE-MRI.

    Methods: We developed a maximum likelihood estimator that combines the phase signal in the DCE-MRI image series with an additional CA estimate, e.g. the estimate obtained from magnitude data. A number of simulations were performed to investigate the ability of the estimator to reduce bias and noise in CA estimates. Noise levels ranging from that of a body coil to that of a dedicated head coil were investigated at both 1.5T and 3T.

    Results: Using the proposed method, the root mean squared error in the bolus peak was reduced from 2.24 to 0.11 mM in the vessels and 0.16 to 0.08 mM in the tumor rim for a noise level equivalent of a 12-channel head coil at 3T. No improvements were seen for tissues with small CA uptake, such as white matter.

    Conclusion: Phase information reduces errors in the estimated CA concentrations. A larger phase response from higher field strengths or higher CA concentrations yielded better results. Issues such as background phase drift need to be addressed before this method can be applied in vivo.

  • 332.
    Brändström, Helge
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Anestesiologi och intensivvård.
    Grip, Helena
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Hallberg, Per
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper. Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Centrum för medicinsk teknik och fysik (CMTF).
    Grönlund, Christer
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Ängquist, Karl-Axel
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Kirurgi.
    Giesbrecht, Gordon G
    Hand cold recovery responses before and after 15 months of military training in a cold climate2008Inngår i: Aviation, Space and Environmental Medicine, ISSN 0095-6562, E-ISSN 1943-4448, Vol. 79, nr 9, s. 904-908Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    INTRODUCTION: The ability of fingers to rapidly rewarm following cold exposure is a possible indicator of cold injury protection. We categorized the post-cooling hand-rewarming responses of men before and after participation in 15 mo of military training in a cold environment in northern Sweden to determine: 1) if the initial rewarming category was related to the occurrence of local cold injury during training; and 2) if cold training affected subsequent hand-rewarming responses. METHODS: Immersion of the dominant hand in 10 degrees C water for 10 min was performed pre-training on 77 men. Of those, 45 were available for successful post-training retests. Infrared thermography monitored the dorsal hand during 30 min of recovery. Rewarming was categorized as normal, moderate, or slow based on mean fingertip temperature at the end of 30 min of recovery (TFinger,30) and the percentage of time that fingertips were vasodilated (%VD). RESULTS: Cold injury occurrence during training was disproportionately higher in the slow rewarmers (four of the five injuries). Post-training, baseline fingertip temperatures and cold recovery variables increased significantly in moderate and slow rewarmers: TFinger30 increased from 21.9 +/- 4 to 30.4 +/- 6 degrees C (Moderate), and from 17.4 +/- 0 to 22.3 +/- 7 degrees C (Slow); %VD increased from 27.5 +/- 16 to 65.9 +/- 34% (Moderate), and from 0.7 +/- 2 to 31.7 +/- 44% (Slow). CONCLUSIONS: Results of the cold recovery test were related to the occurrence of local cold injury during long-term cold-weather training. Cold training itself improved baseline and cold recovery in moderate and slow rewarmers.

  • 333.
    Brändström, Helge
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Anestesiologi och intensivvård.
    Sundelin, Anna
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Anestesiologi och intensivvård.
    Hoseason, Daniela
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Anestesiologi och intensivvård.
    Sundström, Nina
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Birgander, Richard
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Diagnostisk radiologi.
    Johansson, Göran
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Anestesiologi och intensivvård.
    Winsö, Ola
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Anestesiologi och intensivvård.
    Koskinen, Lars-Owe
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Klinisk neurovetenskap.
    Haney, Michael
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Anestesiologi och intensivvård.
    Risk for intracranial pressure increase related to enclosed air in post-craniotomy patients during air ambulance transport: a retrospective cohort study with simulation2017Inngår i: Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine, ISSN 1757-7241, E-ISSN 1757-7241, Vol. 25, artikkel-id 50Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    BACKGROUND: Post-craniotomy intracranial air can be present in patients scheduled for air ambulance transport to their home hospital. We aimed to assess risk for in-flight intracranial pressure (ICP) increases related to observed intracranial air volumes, hypothetical sea level pre-transport ICP, and different potential flight levels and cabin pressures. METHODS: A cohort of consecutive subdural hematoma evacuation patients from one University Medical Centre was assessed with post-operative intracranial air volume measurements by computed tomography. Intracranial pressure changes related to estimated intracranial air volume effects of changing atmospheric pressure (simulating flight and cabin pressure changes up to 8000 ft) were simulated using an established model for intracranial pressure and volume relations. RESULTS: Approximately one third of the cohort had post-operative intracranial air. Of these, approximately one third had intracranial air volumes less than 11 ml. The simulation estimated that the expected changes in intracranial pressure during 'flight' would not result in intracranial hypertension. For intracranial air volumes above 11 ml, the simulation suggested that it was possible that intracranial hypertension could develop 'inflight' related to cabin pressure drop. Depending on the pre-flight intracranial pressure and air volume, this could occur quite early during the assent phase in the flight profile. DISCUSSION: These findings support the idea that there should be radiographic verification of the presence or absence of intracranial air after craniotomy for patients planned for long distance air transport. CONCLUSIONS: Very small amounts of air are clinically inconsequential. Otherwise, air transport with maintained ground-level cabin pressure should be a priority for these patients.

  • 334.
    Brändström, Helge
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Anestesiologi och intensivvård.
    Wiklund, Urban
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Karlsson, Marcus
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Ängquist, Karl-Axel
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Kirurgi.
    Grip, Helena
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Haney, Michael
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Anestesiologi och intensivvård.
    Autonomic nerve system responses for normal and slow rewarmers after hand cold provocation: effects of long-term cold climate training2013Inngår i: International Archives of Occupational and Environmental Health, ISSN 0340-0131, E-ISSN 1432-1246, Vol. 86, nr 3, s. 357-365Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    PURPOSE: Differences among individuals concerning susceptibility to local cold injury following acute cold exposure may be related to function of the autonomic nervous system. We hypothesized that there are differences in heart rate variability (HRV) between individuals with normal or more pronounced vasoconstriction following cold exposure and that there is an adaptation related to prolonged cold exposure in autonomic nervous system response to cold stimuli.

    METHODS: Seventy-seven young men performed a cold provocation test, where HRV was recorded during cold hand immersion and recovery. Forty-three subjects were re-examined 15 months later, with many months of cold weather training between the tests. Subjects were analyzed as 'slow' and 'normal' rewarmers according to their thermographic rewarming pattern.

    RESULTS: For the 'pre-training' test, before cold climate exposure, normal rewarmers had higher power for low-frequency (P(LF)) and high-frequency (P(HF)) HRV components during the cold provocation test (ANOVA for groups: p = 0.04 and p = 0.005, respectively). There was an approximately 25 % higher P(HF) at the start in normal rewarmers, in the logarithmic scale. Low frequency-to-high frequency ratio (P(LF)/P(HF)) showed lower levels for normal rewarmers (ANOVA for groups: p = 0.04). During the 'post-training' cold provocation test, both groups lacked the marked increase in heart rate that occurred during cold exposure at the 'pre-training' setting. After cold acclimatization (post-training), normal rewarmers showed lower resting power values for the low-frequency and high-frequency HRV components. After winter training, the slow rewarmers showed reduced low-frequency power for some of the cold provocation measurements but not all (average total P(LF), ANOVA p = 0.05), which was not present before winter training.

    CONCLUSIONS: These HRV results support the conclusion that cold adaptation occurred in both groups. We conclude that further prospective study is needed to determine whether cold adaptation provides protection to subjects at higher risk for cold injury, that is, slow rewarmers.

  • 335. Budäus, Lars
    et al.
    Bolla, Michel
    Bossi, Alberto
    Cozzarini, Cesare
    Crook, Juanita
    Widmark, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Wiegel, Thomas
    Functional Outcomes and Complications Following Radiation Therapy for Prostate Cancer: A Critical Analysis of the Literature2012Inngår i: European Urology, ISSN 0302-2838, E-ISSN 1873-7560, Vol. 61, nr 1, s. 112-127Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    CONTEXT: Prostate cancer (PCa) patients have many options within the realms of surgery or radiation therapy (RT). Technical advancements in RT planning and delivery have yielded different approaches, such as external beam, brachytherapy, and newer approaches such as image-guided tomotherapy or volumetric-modulated arc therapy. The selection of the optimal RT treatment for the individual is still a point of discussion, and the debate centres on two important outcomes-namely, cancer control and reduction of side-effects.

    OBJECTIVE: To critically review and summarise the available literature on functional outcomes and rectal sequelae following RT for PCa treatment.

    EVIDENCE ACQUISITION: A review of the literature published between 1999 and 2010 was performed using Medline and Scopus search. Relevant reports were identified using the terms prostate cancer, radiotherapy, functional outcomes, external beam radiation, brachytherapy, IMRT, quality of life, and tomotherapy and were critically reviewed and summarised.

    EVIDENCE SYNTHESIS: Related to nonuniform definition of their assessed functional end points and uneven standards of reporting, only a minority of series retrieved could be selected for analyses. Moreover, patterns of patient selection for different types of RT, inherent differences in the RT modalities, and the presence or absence of hormonal treatment also limit the ability to synthesise results from different publications or perform meta-analyses across the different treatment types. Nonetheless, several studies agree that recent technical improvements in the field of RT planning and delivery enable the administration of higher doses with equal or less toxicity. Regardless of the type of RT, the most frequently considered functional end points in the published analyses are gastrointestinal (GI) complications and rectal bleeding. Established risk factors for acute or late toxicities after RT include advanced age, larger rectal volume, a history of prior abdominal surgery, the concomitant use of androgen deprivation, preexisting diabetes mellitus, haemorrhoids, and inflammatory bowel disease (IBD). Similarly, mild acute irritative urinary symptoms are reported in several studies, whereas total urinary incontinence and other severe urinary symptoms are rare. Pretreatment genitourinary complaints, prior transurethral resection of the prostate (TURP), and the presence of acute genitourinary toxicity are suggested as contributing to long-term urinary morbidity. Erectile dysfunction (ED) is not an immediate side-effect of RT, and the occurrence of spontaneous erections before treatment is the best predictor for preserving erections sufficient for intercourse. In addition, the use of magnetic resonance imaging (MRI) permits a reduction in the dose delivered to vascular structures critical for erectile function.

    CONCLUSIONS: In the future, further improvement in RT planning and delivery will decrease side-effects and permit administration of higher doses. Related to the anatomy of the prostate, these higher doses may favour rectal sparing while not readily sparing the urethra and bladder neck. As a consequence, there may be a future shift from dose-limiting long-term rectal morbidity towards long-term urinary morbidity. In the absence of prospective randomised trials comparing different types of surgical and RT-based treatments in PCa, the introduction of validated tools for reporting functional and clinical outcomes is crucial for evaluating and identifying each individual's best treatment choice.

  • 336. Bujila, R
    et al.
    Kull, L
    Nowik, P
    Poludniowski, G
    Andersson, Jonas
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Characterization of Beam Shaping Filters and Photon Spectra From HVL Profiles in CT2016Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Purpose: Advanced dosimetry in CT (e.g., the Monte Carlo method) requires an accurate characterization of the shaped filter and radiation quality used during a scan. The purpose of this work was to develop a method where half value layer (HVL) profiles along shaped filters could be made. From the HVL profiles, the beam shaping properties and effective photon spectrum for a particular scan can be inferred.

    Methods: A measurement rig was developed to allow determinations of the HVL under a scatter-free narrow-beam geometry and constant focal spot to ionization chamber distance, for different fan angles. For each fan angle, the HVL is obtained by fitting the transmission of radiation through different thicknesses of an Al absorber (type 1100) using an appropriate model. The effective Al thickness of shaped filters and effective photon spectra are estimated using a model of photon emission from a Tungsten anode. This method is used to obtain the effective photon spectra and effective Al thickness of shaped filters for a CT scanner recently introduced to the market.

    Results: This study resulted in a set of effective photon spectra (central ray) for each kVp along with effective Al thicknesses of the different shaped filters. The effective photon spectra and effective Al thicknesses of shaped filters were used to obtain numerically approximated HVL profiles and compared to measured HVL profiles (mean absolute percentage error = 0.02). The central axis HVL found in the vendor’s technical documentation were compared to approximated HVL values (mean absolute percentage error = 0.03).

    Conclusion: This work has resulted in a unique method of measuring HVL profiles along shaped filters in CT. Further, the effective photon spectra and the effective Al thicknesses of shaped filters that were obtained can be incorporated into Monte Carlo simulations.

  • 337. Bujila, Robert
    et al.
    Kull, Love
    Danielsson, Mats
    Andersson, Jonas
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Applying three different methods of measuring CTDIfree air to the extended CTDI formalism for wide-beam scanners (IEC 60601-2-44): a comparative study2018Inngår i: Journal of Applied Clinical Medical Physics, ISSN 1526-9914, E-ISSN 1526-9914, Vol. 19, nr 4, s. 281-289Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Purpose: The weighted CT dose index (CTDIw) has been extended for a nominal total collimation width (nT) greater than 40 mm and relies on measurements of CTDfree air. The purpose of this work was to compare three methods of measuring CTDIfree air and subsequent calculations of CTDIw to investigate their clinical appropriateness.

    Methods: The CTDIfree air, for multiple nTs up to 160 mm, was calculated from (1) high-resolution air kerma profiles from a step-and-shoot translation of a liquid ionization chamber (LIC) (considered to be a dosimetric reference), (2) pencil ionization chamber (PIC) measurements at multiple contiguous positions, and (3) air kerma profiles obtained through the continuous translation of a solid-state detector. The resulting CTDIfree air was used to calculate the CTDIw, per the extended formalism, and compared.

    Results: The LIC indicated that a 40 mm nT should not be excluded from the extension of the CTDIw formalism. The solid-state detector differed by as much as 8% compared to the LIC. The PIC was the most straightforward method and gave equivalent results to the LIC.

    Conclusions: The CTDIw calculated with the latest CTDI formalism will differ most for 160 mm nTs (e.g., whole-organ perfusion or coronary CT angiography) compared to the previous CTDI formalism. Inaccuracies in the measurement of CTDIfree air will subsequently manifest themselves as erroneous calculations of the CTDIw, for nTs greater than 40 mm, with the latest CTDI formalism. The PIC was found to be the most clinically feasible method and was validated against the LIC.

  • 338. Burman, Joachim
    et al.
    Iacobaeus, Ellen
    Svenningsson, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Klinisk neurovetenskap.
    Lycke, Jan
    Gunnarsson, Martin
    Nilsson, Petra
    Vrethem, Magnus
    Fredrikson, Sten
    Martin, Claes
    Sandstedt, Anna
    Uggla, Bertil
    Lenhoff, Stig
    Johansson, Jan-Erik
    Isaksson, Cecilia
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Hägglund, Hans
    Carlson, Kristina
    Fagius, Jan
    Autologous haematopoietic stem cell transplantation for aggressive multiple sclerosis: the Swedish experience2014Inngår i: Journal of Neurology, Neurosurgery and Psychiatry, ISSN 0022-3050, E-ISSN 1468-330X, Vol. 85, nr 10, s. 1116-1121Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    BACKGROUND: Autologous haematopoietic stem cell transplantation (HSCT) is a viable option for treatment of aggressive multiple sclerosis (MS). No randomised controlled trial has been performed, and thus, experiences from systematic and sustained follow-up of treated patients constitute important information about safety and efficacy. In this observational study, we describe the characteristics and outcome of the Swedish patients treated with HSCT for MS. METHODS: Neurologists from the major hospitals in Sweden filled out a follow-up form with prospectively collected data. Fifty-two patients were identified in total; 48 were included in the study and evaluated for safety and side effects; 41 patients had at least 1 year of follow-up and were further analysed for clinical and radiological outcome. In this cohort, 34 patients (83%) had relapsing-remitting MS, and mean follow-up time was 47 months. RESULTS: At 5 years, relapse-free survival was 87%; MRI event-free survival 85%; expanded disability status scale (EDSS) score progression-free survival 77%; and disease-free survival (no relapses, no new MRI lesions and no EDSS progression) 68%. Presence of gadolinium-enhancing lesions prior to HSCT was associated with a favourable outcome (disease-free survival 79% vs 46%, p=0.028). There was no mortality. The most common long-term side effects were herpes zoster reactivation (15%) and thyroid disease (8.4%). CONCLUSIONS: HSCT is a very effective treatment of inflammatory active MS and can be performed with a high degree of safety at experienced centres.

  • 339.
    Burström, Lage
    et al.
    Umeå universitet, Medicinsk fakultet, Folkhälsa och klinisk medicin, Yrkes- och miljömedicin.
    Hagberg, Mats
    Lundström, Ronnie
    Umeå universitet, Medicinsk fakultet, Folkhälsa och klinisk medicin, Yrkes- och miljömedicin. Umeå universitet, Medicinsk fakultet, Strålningsvetenskaper.
    Nilsson, Tohr
    Umeå universitet, Medicinsk fakultet, Folkhälsa och klinisk medicin, Yrkes- och miljömedicin.
    Relationship between hand-arm vibration exposure and onset time for symptoms in a heavy engineering production workshop.2006Inngår i: Scandinavian journal of work, environment & health, ISSN 0355-3140, Vol. 32, nr 3, s. 198-203Artikkel i tidsskrift (Fagfellevurdert)
  • 340.
    Burström, Lage
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Yrkes- och miljömedicin.
    Jonsson, Håkan
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Björ, Bodil
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Yrkes- och miljömedicin.
    Hjalmarsson, Ulla
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Yrkes- och miljömedicin.
    Nilsson, Tohr
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Yrkes- och miljömedicin.
    Reuterwall, Christina
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Yrkes- och miljömedicin.
    Wahlström, Jens
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Yrkes- och miljömedicin.
    Daily text messages used as a method for assessing low back pain among workers2016Inngår i: Journal of Clinical Epidemiology, ISSN 0895-4356, E-ISSN 1878-5921, nr 70, s. 45-51Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    OBJECTIVES: To evaluate a method for collecting data concerning low back pain (LBP) using daily text messages and to characterize the reported LBP in terms of intensity, variability, and episodes.

    STUDY DESIGN AND SETTING: We conducted a cohort study of LBP among workers used by a mining company. The participants were asked to answer the question "How much pain have you had in your lower back in the last 24 hours on a scale from 0 to 10, where 0 = no pain and 10 = the worst pain imaginable" once a day for 5 weeks, with this process being repeated 6 months later.

    RESULTS: A total of 121 workers participated in the first period of data collection, and 108 participated in the second period. The daily response rate was 93% for both periods, and cluster analysis was shown to be a feasible statistical method for clustering LBP into subgroups of low, medium, and high pain. The daily text messages method also worked well for assessing the episodic nature of LBP.

    CONCLUSION: We have demonstrated a method for repeatedly measuring of LBP using daily text messages. The data permitted clustering into subgroups and could be used to define episodes of LBP.

  • 341.
    Burzynska, A Z
    et al.
    Max Planck Institute for Human Development, Berlin.
    Preuschhof, C
    Max Planck Institute for Human Development, Berlin.
    Bäckman, L
    Max Planck Institute for Human Development, Berlin, Karolinska Institute.
    Nyberg, Lars
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Fysiologi. Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Diagnostisk radiologi.
    Li, S-C
    Max Planck Institute for Human Development, Berlin.
    Lindenberger, U
    Max Planck Institute for Human Development, Berlin, .
    Heekeren, H R
    Max Planck Institute for Human Development, Berlin, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig.
    Age-related differences in white matter microstructure: region-specific patterns of diffusivity.2010Inngår i: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 49, nr 3, s. 2104-2112Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We collected MRI diffusion tensor imaging data from 80 younger (20-32 years) and 63 older (60-71 years) healthy adults. Tract-based spatial statistics (TBSS) analysis revealed that white matter integrity, as indicated by decreased fractional anisotropy (FA), was disrupted in numerous structures in older compared to younger adults. These regions displayed five distinct region-specific patterns of age-related differences in other diffusivity properties: (1) increases in both radial and mean diffusivity; (2) increases in radial diffusivity; (3) no differences in parameters other than FA; (4) a decrease in axial and an increase in radial diffusivity; and (5) a decrease in axial and mean diffusivity. These patterns suggest different biological underpinnings of age-related decline in FA, such as demyelination, Wallerian degeneration, gliosis, and severe fiber loss, and may represent stages in a cascade of age-related degeneration in white matter microstructure. This first simultaneous description of age-related differences in FA, mean, axial, and radial diffusivity requires histological and functional validation as well as analyses of intermediate age groups and longitudinal samples.

  • 342.
    Bylund, Annika
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för samhällsmedicin och rehabilitering, Geriatrik.
    Saarinen, Niina
    Zhang, Jie-Xian
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Näringsforskning.
    Bergh, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Widmark, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Johansson, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Parodontologi.
    Lundin, Eva
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Adlercreutz, Herman
    Hallmans, Göran
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Näringsforskning.
    Stattin, Pär
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Urologi och andrologi.
    Mäkelä, Sari
    Anticancer effects of a plant lignan 7-hydroxymatairesinol on a prostate cancer model in vivo.2005Inngår i: Experimental biology and medicine (Maywood, N.J.: Print), ISSN 1535-3702, E-ISSN 1535-3699, Vol. 230, nr 3, s. 217-223Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Clinical intervention studies and experimental studies with lignan-rich diets suggest that lignans may have inhibitory effects on prostate cancer, but no clinical or experimental studies with purified lignans have been published. The purpose of this study was to investigate the effect of a plant lignan 7-hydroxymatairesinol (HMR) on LNCaP human prostate cancer xenografts in athymic mice. Athymic nude male mice were injected subcutaneously with LNCaP cells. Starting 3 days after tumor cell injections, a control diet or a control diet supplemented with 0.15% or 0.30% of HMR was administered to mice and the tumor take rate and growth was observed for 9 weeks. HMR diet inhibited the growth of LNCaP tumors. Mice treated with HMR had smaller tumor volume, lower tumor take rate, increased proportion of nongrowing tumors, and higher tumor cell apoptotic index compared with controls. Furthermore, the cell proliferation index was reduced in mice receiving the 0.30% HMR diet compared with mice receiving the control diet. Our results suggest that dietary HMR started at the early phase of the tumor development inhibits the growth of the LNCaP human prostate cancer xenografts in athymic male mice.

  • 343.
    Bylund, Mikael
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Jonsson, Joakim
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Lundman, Josef
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Brynolfsson, Patrik
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Garpebring, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Nyholm, Tufve
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Löfstedt, Tommy
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Using deep learning to generate synthetic CTs for radiotherapy treatment planning2018Inngår i: Radiotherapy and Oncology, ISSN 0167-8140, E-ISSN 1879-0887, Vol. 127, s. S283-S283Artikkel i tidsskrift (Annet vitenskapelig)
  • 344. Bystrom, Sanna
    et al.
    Fredolini, Claudia
    Edqvist, Per-Henrik
    Nyaiesh, Etienne-Nicholas
    Drobin, Kimi
    Uhlen, Mathias
    Bergqvist, Michael
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper. Centre for Research and Development, Uppsala University, 751 85 Uppsala, Sweden; Region Gävleborg, Gävle sjukhus, 801 88 Gävle, Sweden.
    Ponten, Fredrik
    Schwenk, Jochen M.
    Affinity Proteomics Exploration of Melanoma Identifies Proteins in Serum with Associations to T-Stage and Recurrence2017Inngår i: Translational Oncology, ISSN 1944-7124, E-ISSN 1936-5233, Vol. 10, nr 3, s. 385-395Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    BACKGROUND: Blood-based proteomic profiling may aid and expand our understanding of diseases and their different phenotypes. The aim of the presented study was to profile serum samples from patients with malignant melanoma using affinity proteomic assays to describe proteins in the blood stream that are associated to stage or recurrence of melanoma.

    MATERIAL AND METHODS: Multiplexed protein analysis was conducted using antibody suspension bead arrays. A total of 232 antibodies against 132 proteins were selected from (i) a screening with 4595 antibodies and 32 serum samples from melanoma patients and controls, (ii) antibodies used for immunohistochemistry, (iii) protein targets previously related with melanoma. The analysis was performed with 149 serum samples from patients with malignant melanoma. Antibody selectivity was then assessed by Western blot, immunocapture mass spectrometry, and epitope mapping. Lastly, indicative antibodies were applied for IHC analysis of melanoma tissues.

    RESULTS: Serum levels of regucalcin (RGN) and syntaxin 7 (STX7) were found to be lower in patients with both recurring tumors and a high Breslow's thickness (T-stage 3/4) compared to low thickness (T-stage 1/2) without disease recurrence. Serum levels of methylenetetrahydrofolate dehydrogenase 1-like (MTHFD1L) were instead elevated in sera of T3/4 patients with recurrence. The analysis of tissue sections with S100A6 and MTHFD1L showed positive staining in a majority of patients with melanoma, and S100A6 was significantly associated to T-stage.

    CONCLUSIONS: Our findings provide a starting point to further study RGN, STX7, MTHFD1L and S100A6 in serum to elucidate their involvement in melanoma progression and to assess a possible contribution to support clinical indications.

  • 345. Bäcklund, J
    et al.
    Clewett Dahl, E
    Skorpil, Mikael
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Is CT indicated in diagnosing sacroiliac joint degeneration?2017Inngår i: Clinical Radiology, ISSN 0009-9260, E-ISSN 1365-229X, Vol. 72, artikkel-id S0009-9260(17)30107-1Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    AIM: To assess the value of computed tomography (CT) in the diagnosis of symptomatic sacroiliac (SI) joint degeneration.

    MATERIALS AND METHODS: CT images from 123 patients with clinically diagnosed SI joint pain were compared to age- and gender-matched controls without chronic back pain or previous back surgery. Degeneration was graded assessing joint space narrowing, osteophytes, subchondral sclerosis, cysts, and vacuum phenomena.

    RESULTS: The mean total score for the patients was 9.6 and for the controls 9.7 (p=0.77). A subgroup analysis of the mean score for the SI joints that were subjected to surgery was 4.3, compared to 4.8 in the conservatively treated SI joints in the patient group (p=0.23) and 4.8 for all SI joints in the control group (p=0.25). For patients with unilateral left-sided pain (n=40), the mean score for the left side was 5.2 and for the right side 4.9 (p=0.49). For patients with right-sided pain (n=41), the mean score for the right side was 4.8 and the left side 4.7 (p=0.55).

    CONCLUSION: The prevalence of SI joint degeneration on CT is equal in symptomatic and non-symptomatic individuals. This study indicates that the value of CT is limited, but further studies are needed to establish if CT has a place in diagnosing SI joint degeneration.

  • 346.
    Bäcklund, Tomas
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Frankel, Jennifer
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Israelsson, Hanna
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Klinisk neurovetenskap. Vrinnevi Hospital, Norrköping, Sweden.
    Malm, Jan
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Klinisk neurovetenskap.
    Sundström, Nina
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Trunk sway in idiopathic normal pressure hydrocephalus: quantitative assessment in clinical practice2017Inngår i: Gait & Posture, ISSN 0966-6362, E-ISSN 1879-2219, s. 62-70, artikkel-id 54Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background: In diagnosis and treatment of patients with idiopathic normal pressure hydrocephalus (iNPH), there is need for clinically applicable, quantitative assessment of balance and gait. Using a body worn gyroscopic system, the aim of this study was to assess postural stability of iNPH patients in standing, walking and during sensory deprivation before and after cerebrospinal fluid (CSF) drainage and surgery. A comparison was performed between healthy elderly (HE) and patients with various types of hydrocephalus (ventriculomegaly (VM)).

    Methods: Trunk sway was measured in 31 iNPH patients, 22 VM patients and 58 HE. Measurements were performed at baseline in all subjects, after CSF drainage in both patient groups and after shunt surgery in the iNPH group.

    Results: Preoperatively, the iNPH patients had significantly higher trunk sway compared to HE, specifically for the standing tasks (p < 0.001). Compared to VM, iNPH patients had significantly lower sway velocity during gait in three of four cases on firm support (p < 0.05). Sway velocity improved after CSF drainage and in forward-backward direction after surgery (p < 0.01). Compared to HE both patient groups demonstrated less reliance on visual input to maintain stable posture.

    Conclusions: INPH patients had reduced postural stability compared to HE, particularly during standing, and for differentiation between iNPH and VM patients sway velocity during gait is a promising parameter. A reversible reduction of visual incorporation during standing was also seen. Thus, the gyroscopic system quantitatively assessed postural deficits in iNPH, making it a potentially useful tool for aiding in future diagnoses, choices of treatment and clinical follow-up. 

  • 347.
    Bäckman, Lars
    et al.
    Aging Research Center, Karolinska Institutet, Gävlegatan 16, SE-113 30 Stockholm, Sweden.
    Karlsson, Sari
    Aging Research Center, Karolinska Institutet, Gävlegatan 16, SE-113 30 Stockholm, Sweden.
    Fischer, Håkan
    Aging Research Center, Karolinska Institutet, Gävlegatan 16, SE-113 30 Stockholm, Sweden.
    Karlsson, Per
    Department of Clinical Neuroscience, Psychiatry Section, Karolinska Institutet, Stockholm, Sweden.
    Brehmer, Yvonne
    Aging Research Center, Karolinska Institutet, Gävlegatan 16, SE-113 30 Stockholm, Sweden.
    Rieckmann, Anna
    Aging Research Center, Karolinska Institutet, Gävlegatan 16, SE-113 30 Stockholm, Sweden.
    Macdonald, Stuart WS
    Aging Research Center, Karolinska Institutet, Gävlegatan 16, SE-113 30 Stockholm, Sweden; Department of Psychology, University of Victoria, Canada .
    Farde, Lars
    Department of Clinical Neuroscience, Psychiatry Section, Karolinska Institutet, Stockholm, Sweden.
    Nyberg, Lars
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper. Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB).
    Dopamine D(1) receptors and age differences in brain activation during working memory2011Inngår i: Neurobiology of Aging, ISSN 0197-4580, E-ISSN 1558-1497, Vol. 32, nr 10, s. 1849-1856Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In an fMRI study, 20 younger and 20 healthy older adults were scanned while performing a spatial working-memory task under two levels of load. On a separate occasion, the same subjects underwent PET measurements using the radioligand [(11)C] SCH23390 to determine dopamine D(1) receptor binding potential (BP) in caudate nucleus and dorsolateral prefrontal cortex (DLPFC). The fMRI study revealed a significant load modulation of brain activity (higher load>lower load) in frontal and parietal regions for younger, but not older, adults. The PET measurements showed marked age-related reductions of D(1) BP in caudate and DLPFC. Statistical control of caudate and DLPFC D(1) binding eliminated the age-related reduction in load-dependent BOLD signal in left frontal cortex, and attenuated greatly the reduction in right frontal and left parietal cortex. These findings suggest that age-related alterations in dopaminergic neurotransmission may contribute to underrecruitment of task-relevant brain regions during working-memory performance in old age.

  • 348. Bäckman, Lars
    et al.
    Lindenberger, Ulman
    Li, Shu-Chen
    Nyberg, Lars
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Fysiologi. Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Linking cognitive aging to alterations in dopamine neurotransmitter functioning: Recent data and future avenues2010Inngår i: Neuroscience and Biobehavioral Reviews, ISSN 0149-7634, E-ISSN 1873-7528, Vol. 34, nr 5, s. 670-677Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    Molecular-imaging studies of dopaminergic neurotransmission measure biomarkers of dopamine (DA), such as the DA transporter and D(1) and D(2) receptor densities in the living brain. These studies indicate that individual differences in DA functions are linked to cognitive performance irrespective of age, and serve as powerful mediators of age-related decline in executive functioning, episodic memory, and perceptual speed. This focused review targets several recent findings pertaining to these relationships. Specifically, we discuss novel evidence concerning (a) the role of DA in within-person cognitive variability; (b) age-related differences in DA release during cognitive processing; (c) DA release following cognitive training in younger and older adults; and (d) the relationship between DA and task-induced functional brain activity. Based on these lines of empirical inquiry, we outline a series of avenues for future research on aging, DA, and cognition.

  • 349.
    Bäckman, Lars
    et al.
    Aging Research Center, Karolinska Institute, Stockholm, Sweden.
    Nyberg, Lars
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Diagnostisk radiologi. Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB).
    Soveri, Anna
    Department of Psychology and Logopedics, Åbo Akademi University, Turku, Finland.
    Johansson, Jarkko
    Turku PET Center, University of Turku, Turku, Finland.
    Andersson, Micael
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB).
    Dahlin, Erika
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB).
    Neely, Anna S
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi.
    Virta, Jere
    Turku PET Center, University of Turku, Turku, Finland.
    Laine, Matti
    Department of Psychology and Logopedics, Åbo Akademi University, Turku, Finland.
    Rinne, Juha O
    Turku PET Center, University of Turku, Turku, Finland.
    Effects of working-memory training on striatal dopamine release2011Inngår i: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 333, nr 6043, s. 718-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Updating of working memory has been associated with striato-frontal brain regions and phasic dopaminergic neurotransmission. We assessed raclopride binding to striatal dopamine (DA) D2 receptors during a letter-updating task and a control condition before and after 5 weeks of updating training. Results showed that updating affected DA activity before training and that training further increased striatal DA release during updating. These findings highlight the pivotal role of transient neural processes associated with D2 receptor activity in working memory.

  • 350. Bäckman, Lars
    et al.
    Waris, Otto
    Johansson, Jarkko
    Andersson, Micael
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB).
    Rinne, Juha O.
    Alakurtti, Kati
    Soveri, Anna
    Laine, Matti
    Nyberg, Lars
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper. Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB).
    Increased dopamine release after working-memory updating training: Neurochemical correlates of transfer2017Inngår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, artikkel-id 7160Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Previous work demonstrates that working-memory (WM) updating training results in improved performance on a letter-memory criterion task, transfers to an untrained n-back task, and increases striatal dopamine (DA) activity during the criterion task. Here, we sought to replicate and extend these findings by also examining neurochemical correlates of transfer. Four positron emission tomography (PET) scans using the radioligand raclopride were performed. Two of these assessed DAD2 binding (letter memory; n-back) before 5 weeks of updating training, and the same two scans were performed post training. Key findings were (a) pronounced training-related behavioral gains in the lettermemory criterion task, (b) altered striatal DAD2 binding potential after training during letter-memory performance, suggesting training-induced increases in DA release, and (c) increased striatal DA activity also during the n-back transfer task after the intervention, but no concomitant behavioral transfer. The fact that the training-related DA alterations during the transfer task were not accompanied by behavioral transfer suggests that increased DA release may be a necessary, but not sufficient, condition for behavioral transfer to occur.

45678910 301 - 350 of 2664
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf