| 1. |
- de Frias, Cindy M., et al.
(författare)
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Cholesterol and triglycerides moderate the effect of apolipoprotein E on memory functioning in older adults.
- 2007
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Ingår i: Journal of Gerontology: Psychological Sciences. - Washington : The gerontological society of America. - 1079-5014 .- 1758-5368. ; 62B:2, s. P112-P118
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Tidskriftsartikel (refereegranskat)abstract
- We used data from the Betula Study to examine associations between total cholesterol, triglycerides, and apolipoprotein E on 10-year changes in cognitive performance. Tests assessing episodic memory (recall and recognition), semantic memory (knowledge and fluency), and visuospatial ability (block design) were administered to 524 nondemented adults (initial age of 55-80 years); multilevel modeling was applied to the data. Higher triglyceride levels were associated with a decline in verbal knowledge. Lipid levels moderated the influence of apolipoprotein E on episodic memory, such that among epsilon 4 allele carriers, decline in recognition was noted for individuals with higher cholesterol levels. Cholesterol and triglyceride levels are pharmacologically modifiable risk factors that account for variation In normal cognitive aging.
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| 2. |
- Janek, Sara, 1977-, et al.
(författare)
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Development of dose delivery verification by PET imaging of photonuclear reactions following high energy photon therapy
- 2006
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Ingår i: Physics in Medicine and Biology. - : IOP Publishing. - 0031-9155 .- 1361-6560. ; 51:22, s. 5769-
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Tidskriftsartikel (refereegranskat)abstract
- A method for dose delivery monitoring after high energy photon therapy has been investigated based on positron emission tomography (PET). The technique is based on the activation of body tissues by high energy bremsstrahlung beams, preferably with energies well above 20 MeV, resulting primarily in 11C and 15O but also 13N, all positron-emitting radionuclides produced by photoneutron reactions in the nuclei of 12C, 16O and 14N. A PMMA phantom and animal tissue, a frozen hind leg of a pig, were irradiated to 10 Gy and the induced positron activity distributions were measured off-line in a PET camera a couple of minutes after irradiation. The accelerator used was a Racetrack Microtron at the Karolinska University Hospital using 50 MV scanned photon beams. From photonuclear cross-section data integrated over the 50 MV photon fluence spectrum the predicted PET signal was calculated and compared with experimental measurements. Since measured PET images change with time post irradiation, as a result of the different decay times of the radionuclides, the signals from activated 12C, 16O and 14N within the irradiated volume could be separated from each other. Most information is obtained from the carbon and oxygen radionuclides which are the most abundant elements in soft tissue. The predicted and measured overall positron activities are almost equal (−3%) while the predicted activity originating from nitrogen is overestimated by almost a factor of two, possibly due to experimental noise. Based on the results obtained in this first feasibility study the great value of a combined radiotherapy–PET–CT unit is indicated in order to fully exploit the high activity signal from oxygen immediately after treatment and to avoid patient repositioning. With an RT–PET–CT unit a high signal could be collected even at a dose level of 2 Gy and the acquisition time for the PET could be reduced considerably. Real patient dose delivery verification by means of PET imaging seems to be applicable provided that biological transport processes such as capillary blood flow containing mobile 15O and 11C in the activated tissue volume can be accounted for.
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| 3. |
- Lövdén, Martin, et al.
(författare)
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Studying Individual Aging in an Interindividual Context : Typical Paths of Age-Related, Dementia-Related, and Mortality-Related Cognitive Development in Old Age
- 2005
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Ingår i: Psychology and Aging. - Washington : American Psychological Association (APA). - 0882-7974 .- 1939-1498. ; 20:2, s. 303-316
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Tidskriftsartikel (refereegranskat)abstract
- This study has 2 objectives: (a) to explore typical paths of cognitive development associated with aging, terminal decline, and dementia and (b) to promote and illustrate an individual-oriented approach to the study of cognitive aging based on longitudinal panel data from a population-based sample (N = 500; age range-sub(T1)= 60-80, where T refers to time) tested at 3 occasions 5 years apart. Results document interindividual differences in multivariate patterns of change. Although cognitive changes generally covary, the present study indicates that subgroups of individuals develop along different paths characterized by selective changes in subsets of cognitive functions. Typical progression of dementia followed a developmental cascade from low declarative memory, via low functioning across all observed cognitive measures, to dementia diagnosis, and finally, death.
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| 4. |
- Aaro Jonsson, Catherine, 1963-, et al.
(författare)
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Long-term cognitive outcome after neurosurgically treated childhood traumatic brain injury
- 2009
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Ingår i: Brain Injury. - : Taylor & Francis. - 0269-9052 .- 1362-301X. ; 23:13-14, s. 1008-1016
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To explore the cognitive long term outcome of two cohorts of patients neurosurgically treated for childhood traumatic brain injury (CTBI), either in 1987-1991 according to an older concept, or 1997-2001 with a stronger emphasis on volume targeted interventions. Research design and methods: Participants in the two cohorts were subject to an extensive neuropsychological assessment, 13.2 and 6.1 years post injury, respectively. In a between group design, assessment results of the two cohorts, n 18 and n 23, were compared to each other and to controls. Data were analyzed with multivariate analyses of variance. Results: Long-term cognitive deficits for both groups of similar magnitude and character were observed in both groups. Abilities were especially low regarding executive and memory function and verbal IQ. The cognitive results are discussed in terms of vulnerability of verbal functions and decreased executive control over memory-functions. Conclusions: There is a definite need for long term follow up of cognitive deficits after neurosurgically treated CTBI, also with the newer neurosurgical concept. Verbal learning and the executive control over memory functions should be addressed with interventions aimed at restoration, coping and compensation.
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| 5. |
- Bill-Axelson, Anna, et al.
(författare)
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Radical prostatectomy versus watchful waiting in localized prostate cancer : the Scandinavian prostate cancer group-4 randomized trial
- 2008
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Ingår i: Journal of the National Cancer Institute. - : Oxford University Press. - 0027-8874 .- 1460-2105. ; 100:16, s. 1144-1154
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The benefit of radical prostatectomy in patients with early prostate cancer has been assessed in only one randomized trial. In 2005, we reported that radical prostatectomy improved prostate cancer survival compared with watchful waiting after a median of 8.2 years of follow-up. We now report results after 3 more years of follow-up.METHODS: From October 1, 1989, through February 28, 1999, 695 men with clinically localized prostate cancer were randomly assigned to radical prostatectomy (n = 347) or watchful waiting (n = 348). Follow-up was complete through December 31, 2006, with histopathologic review and blinded evaluation of causes of death. Relative risks (RRs) were estimated using the Cox proportional hazards model. Statistical tests were two-sided.RESULTS: During a median of 10.8 years of follow-up (range = 3 weeks to 17.2 years), 137 men in the surgery group and 156 in the watchful waiting group died (P = .09). For 47 of the 347 men (13.5%) who were randomly assigned to surgery and 68 of the 348 men (19.5%) who were not, death was due to prostate cancer. The difference in cumulative incidence of death due to prostate cancer remained stable after about 10 years of follow-up. At 12 years, 12.5% of the surgery group and 17.9% of the watchful waiting group had died of prostate cancer (difference = 5.4%, 95% confidence interval [CI] = 0.2 to 11.1%), for a relative risk of 0.65 (95% CI = 0.45 to 0.94; P = .03). The difference in cumulative incidence of distant metastases did not increase beyond 10 years of follow-up. At 12 years, 19.3% of men in the surgery group and 26% of men in the watchful waiting group had been diagnosed with distant metastases (difference = 6.7%, 95% CI = 0.2 to 13.2%), for a relative risk of 0.65 (95% CI = 0.47 to 0.88; P = .006). Among men who underwent radical prostatectomy, those with extracapsular tumor growth had 14 times the risk of prostate cancer death as those without it (RR = 14.2, 95% CI = 3.3 to 61.8; P < .001).CONCLUSION: Radical prostatectomy reduces prostate cancer mortality and risk of metastases with little or no further increase in benefit 10 or more years after surgery.
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| 6. |
- Costa Ferreira, Brigida, et al.
(författare)
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The impact of different dose-response parameters on biologically optimized IMRT in breast cancer.
- 2008
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Ingår i: Physics in Medicine and Biology. - : IOP Publishing. - 0031-9155 .- 1361-6560. ; 53:10, s. 2733-52
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Tidskriftsartikel (refereegranskat)abstract
- The full potential of biologically optimized radiation therapy can only be maximized with the prediction of individual patient radiosensitivity prior to treatment. Unfortunately, the available biological parameters, derived from clinical trials, reflect an average radiosensitivity of the examined populations. In the present study, a breast cancer patient of stage I-II with positive lymph nodes was chosen in order to analyse the effect of the variation of individual radiosensitivity on the optimal dose distribution. Thus, deviations from the average biological parameters, describing tumour, heart and lung response, were introduced covering the range of patient radiosensitivity reported in the literature. Two treatment configurations of three and seven biologically optimized intensity-modulated beams were employed. The different dose distributions were analysed using biological and physical parameters such as the complication-free tumour control probability (P(+)), the biologically effective uniform dose (D), dose volume histograms, mean doses, standard deviations, maximum and minimum doses. In the three-beam plan, the difference in P(+) between the optimal dose distribution (when the individual patient radiosensitivity is known) and the reference dose distribution, which is optimal for the average patient biology, ranges up to 13.9% when varying the radiosensitivity of the target volume, up to 0.9% when varying the radiosensitivity of the heart and up to 1.3% when varying the radiosensitivity of the lung. Similarly, in the seven-beam plan, the differences in P(+) are up to 13.1% for the target, up to 1.6% for the heart and up to 0.9% for the left lung. When the radiosensitivity of the most important tissues in breast cancer radiation therapy was simultaneously changed, the maximum gain in outcome was as high as 7.7%. The impact of the dose-response uncertainties on the treatment outcome was clinically insignificant for the majority of the simulated patients. However, the jump from generalized to individualized radiation therapy may significantly increase the therapeutic window for patients with extreme radio sensitivity or radioresistance, provided that these are identified. Even for radiosensitive patients a simple treatment technique is sufficient to maximize the outcome, since no significant benefits were obtained with a more complex technique using seven intensity-modulated beams portals.
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| 7. |
- Dasu, Alexandru, et al.
(författare)
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Vascular oxygen content and the tissue oxygenation--a theoretical analysis.
- 2008
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Ingår i: Med Phys. - : American Association of Physicists in Medicine (AAPM). - 0094-2405. ; 35:2, s. 539-45
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Several methods exist for evaluating tumor oxygenation as hypoxia is an important prognostic factor for cancer patients. They use different measuring principles that highlight various aspects of oxygenation. The results could be empirically correlated, but it has been suspected that there could be discordances in some cases. This study describes an analysis of the relationship between vascular and tissue oxygenations. Theoretical simulation has been employed to characterize tissue oxygenations for a broad range of distributions of intervessel distances and vascular oxygenations. The results were evaluated with respect to the implications for practical measurements of tissue oxygenations. The findings showed that although the tissue oxygenation is deterministically related to vascular oxygenation, the relationship between them is not unequivocal. Variability also exists between the fractions of values below the sensitivity thresholds of various measurement methods which in turn could be reflected in the power of correlations between results from different methods or in the selection of patients for prognostic studies. The study has also identified potential difficulties that may be encountered at the quantitative evaluation of the results from oxygenation measurements. These could improve the understanding of oxygenation measurements and the interpretation of comparisons between results from various measurement methods.
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| 8. |
- Dasu, Alexandru, et al.
(författare)
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What is the Clinically Relevant Relative Biologic Effectiveness? A Warning for Fractionated Treatments With High Linear Energy Transfer Radiation
- 2008
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Ingår i: International Journal of Radiation Oncology, Biology, Physics. - : Elsevier. - 0360-3016 .- 1879-355X. ; 70:3, s. 867-874
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To study the clinically relevant relative biologic effectiveness (RBE) of fractionated treatments with high linear energy transfer (LET) radiation and to identify the important factors that might influence the transfer of tolerance and curative levels from low LET radiation. These are important questions in the light of the growing interest for the therapeutic use of radiation with higher LET than electrons or photons.METHODS AND MATERIALS: The RBE of various fractionated schedules was analyzed with theoretical models for radiation effect, and the resulting predictions were compared with the published clinical and experimental data regarding fractionated irradiation with high LET radiation.RESULTS: The clinically relevant RBE increased for greater doses per fraction, in contrast to the predictions from single-dose experiments. Furthermore, the RBE for late-reacting tissues appeared to modify more quickly than that for early-reacting tissues. These aspects have quite important clinical implications, because the increased biologic effectiveness reported for this type of radiation would otherwise support the use of hypofractionation. Thus, the differential between acute and late-reacting tissues could put the late-reacting normal tissues at more risk from high LET irradiation; however, at the same time, it could increase the therapeutic window for slow-growing tumors.CONCLUSIONS: The modification of the RBE with the dose per fraction must be carefully taken into consideration when devising fractionated treatments with high LET radiation. Neglecting to do so might result in an avalanche of complications that could obscure the potential advantages of the therapeutic use of this type of radiation.
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| 9. |
- Franzén, Karin, 1958-, et al.
(författare)
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Urinary incontinence in women is not exclusively a medical problem : a population-based study on urinary incontinence and general living conditions
- 2009
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Ingår i: Scandinavian Journal of Urology and Nephrology. - London : Taylor & Francis. - 0036-5599 .- 1651-2065. ; 43:3, s. 226-232
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: The aim of the study was to analyse differences in general health and general living conditions between women with and without urinary incontinence (UI).MATERIAL AND METHODS: This cross-sectional population-based study was conducted in Orebro County, Sweden. A public health questionnaire, "Life and Health", was sent to a randomly selected sample of the population. The questionnaire consisted of 87 questions on broad aspects of general and psychiatric health. An additional questionnaire was enclosed for those respondents who reported experiencing UI. The data were analysed using binary logistic regression. The final study population constituted 4609 women, 1332 of whom had completed both questionnaires. The remaining 3277 had completed only the Life and Health questionnaire. Effect measures were odds ratios (ORs) with corresponding 95% confidence intervals (CIs).RESULTS: Statistically significant associations were found between UI and the occurrence of musculoskeletal pain (OR 1.45, 95% CI 1.20-1.76), fatigue and sleeping disorders (OR 1.59, 95% CI 1.30-1.95), feelings of humiliation (OR 1.29, 95% CI 1.12-1.50), financial problems (OR 1.36, 95% CI 1.11-1.66), and reluctance to seek medical care (OR 1.43, 95% CI 1.21-1.68).CONCLUSION: UI among women is commonly associated with a number of different psychosocial problems as well as an expressed feeling of vulnerability.
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| 10. |
- Qatarneh, Sharif M., et al.
(författare)
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Evaluation of a segmentation procedure to delineate organs for use in construction of a radiation therapy planning atlas
- 2003
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Ingår i: International Journal of Medical Informatics. - 1386-5056 .- 1872-8243. ; 69, s. 39-55
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: This paper evaluates a semi-automatic segmentation procedure to enhance utilizing atlas based treatment plans. For this application, it is crucial to provide a collection of 'reference' organs, restorable from the atlas so that they closely match those of the current patient. To enable assembling representative organs, we developed a semiautomatic procedure using an active contour method. Method: The 3D organ volume was identified by defining contours on individual slices. The initial organ contours were matched to patient volume data sets and then superimposed on them. These starting contours were then adjusted and refined to rapidly find the organ outline of the given patient. Performance was evaluated by contouring organs of different size, shape complexity, and proximity to surrounding structures. We used representative organs defined on CT volumes obtained from 12 patients and compared the resulting outlines to those drawn by a radiologist. Results: A strong correlation was found between the area measures of the delineated liver (r = 0.992), lung (r = 0.996) and spinal cord (r = 0.81), obtained by both segmentation techniques. A paired Student's t-test showed no statistical difference between the two techniques regarding the liver and spinal cord (p > 0.05). Conclusion: This method could be used to form 'standard' organs, which would form part of a whole body atlas (WBA) database for radiation treatment plans as well as to match atlas organs to new patient data.
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