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- Dasu, Alexandru, et al.
(author)
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Treatment modelling : the influence of micro-environmental conditions.
- 2008
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In: Acta Oncol. - : Informa Healthcare. - 1651-226X .- 0284-186X. ; 47:5, s. 896-905
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Journal article (other academic/artistic)abstract
- The interest in theoretical modelling of radiation response has grown steadily from a fast method to estimate the gain of new treatment strategies to an individualisation tool that may be used as part of the treatment planning algorithms. While the advantages of biological optimisation of plans are obvious, accurate theoretical models and realistic information about the micro-environmental conditions in tissues are needed. This paper aimed to investigate the clinical implications of taking into consideration the details of the tumour microenvironmental conditions. The focus was on the availability of oxygen and other nutrients to tumour cells and the relationship between cellular energy reserves and DNA repair ability as this is thought to influence the response of the various hypoxic cells. The choice of the theoretical models for predicting the response (the linear quadratic model or the inducible repair model) was also addressed. The modelling performed in this project has shown that the postulated radiobiological differences between acute and chronic hypoxia have some important clinical implications which may help to understand the mechanism behind the current success rates of radiotherapy. The results also suggested that it is important to distinguish between the two types of hypoxia in predictive assays and other treatment simulations.
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| 2. |
- Dasu, Alexandru, et al.
(author)
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Vascular oxygen content and the tissue oxygenation--a theoretical analysis.
- 2008
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In: Med Phys. - : American Association of Physicists in Medicine (AAPM). - 0094-2405. ; 35:2, s. 539-45
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Journal article (other academic/artistic)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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| 4. |
- Idborg, Helena, et al.
(author)
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STRATIFICATION OF SLE PATIENTS FOR IMPROVED DIAGNOSIS AND TREATMENT
- 2013
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In: Annals of the Rheumatic Diseases. - : BMJ. - 0003-4967 .- 1468-2060. ; 72, s. A80-A80
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Journal article (other academic/artistic)abstract
- Background. Systemic autoimmune diseases (SAIDs) affect about 2% of the population in Western countries. Sufficient diagnostic criteria are lacking due to the heterogeneity within diagnostic categories and apparent overlap regarding symptoms and patterns of autoantibodies between different diagnoses. Systemic lupus erythematosus (SLE) is regarded as a prototype for SAIDs and we hypothesise that subgroups of patients with SLE may have different pathogenesis and should consequently be subject to different treatment strategies.Objectives. Our goal is to find new biomarkers to be used for the identification of more homogenous patient populations for clinical trials and to identify sub-groups of patients with high risk of for example cardiovascular events.Methods. In this study we have utilised 320 SLE patients from the Karolinska lupus cohort and 320 age and gender matched controls. The SLE cohort was characterised based on clinical, genetic and serological data and combined by multivariate data analysis in a systems biology approach to study possible subgroups. A pilot study was designed to verify and investigate suggested subgroups of SLE. Two main subgroups were defined: One group was defined as having SSA and SSB antibodies and a negative lupus anticoagulant test (LAC), i.e., a “Sjögren-like” group. The other group was defined as being negative for SSA and SSB antibodies but positive in the LAC test.i.e. an “APS-like” group. EDTA-plasma from selected patients in these two groups and controls were analysed using a mass spectrometry (MS) based proteomic and metabolomic approach. Pathway analysis was then performed on the obtained data.Results. Our pilot study showed that differences in levels of proteins and metabolites could separate disease groups from population controls. The profile/pattern of involved factors in the complement system supported a division of SLE in two major subgroups, although each individual factor was not significantly different between subgroups. Complement factor 2 (C2) and membrane attack complex (MAC) were analysed in the entire cohort with complementary methods and C2 verifies our results while the levels of MAC did not differ between SLE subgroups. The generated metabolomics data clearly separated SLE patients from controls in both gas chromatography (GC)-MS and liquid chromatography (LC)-MS data. We found for example that tryptophan was lower in the SLE patients compared to controls.Conclusions. Our systems biology approach may lead to a better understanding of the disease and its pathogenesis, and assigning patients into subgroups will result in improved diagnosis and better outcome measures of SLE.
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| 5. |
- Rinnström, Daniel, 1982-, et al.
(author)
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Poor blood pressure control in adults with repaired coarctation of the aorta and hypertension : a register-based study of associated factors
- 2017
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In: Cardiology in the Young. - : Cambridge University Press. - 1047-9511 .- 1467-1107. ; 27:9, s. 1708-1715
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Journal article (other academic/artistic)abstract
- Arterial hypertension is common in adults with repaired coarctation of the aorta, and is associated with several severe complications.This study aimed to investigate the prevalence of poorly controlled (⩾140/90 mmHg) blood pressure among patients with diagnosed hypertension and to identify associated factors.In the national register for CHD, adults with repaired coarctation of the aorta and diagnosed hypertension – defined as a registry diagnosis and/or use of anti-hypertensive prescription medication – were identified. Logistic regression analysis was used to identify variables associated with poorly controlled blood pressure.Of the 243 included patients, 27.2% were female, the mean age was 45.4±15.3 years, and 52.3% had poorly controlled blood pressure at the last registration. In a multivariable model, age (years) (OR 1.03, CI 1.01–1.06, p=0.008) was independently associated with poorly controlled blood pressure and so was systolic arm–leg blood pressure gradient in the ranges [10, 20] mmHg (OR 4.92, CI 1.76–13.79, p=0.002) to >20 mmHg (OR 9.93, CI 2.99–33.02, p<0.001), in comparison with the reference interval [0, 10] mmHg. Patients with poorly controlled blood pressure had, on average, more types of anti-hypertensive medication classes prescribed (1.9 versus 1.5, p=0.003).Poorly controlled blood pressure is common among patients with repaired coarctation of the aorta and diagnosed hypertension, despite what seems to be more intensive treatment. A systolic arm–leg blood pressure gradient is associated with poorly controlled blood pressure, even at low levels usually not considered for intervention, and may be an indicator of hypertension that is difficult to treat.
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| 9. |
- Lahermo, P, et al.
(author)
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A quality assessment survey of SNP genotyping laboratories
- 2006
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In: Human Mutation. - : Hindawi Limited. - 1059-7794 .- 1098-1004. ; 27:7, s. 711-714
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Journal article (other academic/artistic)abstract
- To survey the quality of SNP genotyping, a joint Nordic quality assessment (QA) round was organized between 11 laboratories in the Nordic and Baltic countries. The QA round involved blinded genotyping of 47 DNA samples for 18 or six randomly selected SNPs. The methods used by the participating laboratories included all major platforms for small- to medium-size SNP genotyping. The laboratories used their standard procedures for SNP assay design, genotyping, and quality control. Based on the joint results from all laboratories, a consensus genotype for each DNA sample and SNP was determined by the coordinator of the survey, and the results from each laboratory were compared to this genotype. The overall genotyping accuracy achieved in the survey was excellent. Six laboratories delivered genotype data that were in full agreement with the consensus genotype. The average accuracy per SNP varied from 99.1 to 100% between the laboratories, and it was frequently 100% for the majority of the assays for which SNP genotypes were reported. Lessons from the survey are that special attention should be given to the quality of the DNA samples prior to genotyping, and that a conservative approach for calling the genotypes should be used to achieve a high accuracy.
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