University of Aberdeen

About: University of Aberdeen is a education organization based out in Aberdeen, United Kingdom. It is known for research contribution in the topics: Population & Health care. The organization has 21174 authors who have published 49962 publications receiving 2105479 citations. The organization is also known as: Aberdeen University.

Anticoagulants for acute ischaemic stroke

Abstract: Background Most ischaemic strokes are caused by blood clots blocking an artery in the brain. Clot prevention with anticoagulants might improve outcome if bleeding risks were low. This is an update of a Cochrane review first published in 1995, and previously updated in 2004. Objectives To assess the effect of anticoagulant therapy versus control in the early treatment (less than 14 days) of patients with acute ischaemic stroke. Search methods We searched the Cochrane Stroke Group Trials Register (last searched 2 October 2007), and two Internet clinical trials registries for relevant ongoing studies (last searched October 2007). Selection criteria Randomised trials comparing early anticoagulant therapy (started within two weeks of stroke onset) with control in patients with acute presumed or confirmed ischaemic stroke. Data collection and analysis Two review authors independently selected trials for inclusion, assessed trial quality, and extracted the data. Main results Twenty-four trials involving 23,748 participants were included. The quality of the trials varied considerably. The anticoagulants tested were standard unfractionated heparin, low-molecular-weight heparins, heparinoids, oral anticoagulants, and thrombin inhibitors. Based on 11 trials (22,776 participants) there was no evidence that anticoagulant therapy reduced the odds of death from all causes (odds ratio (OR) 1.05; 95% confidence interval (CI) 0.98 to 1.12) at the end of follow up. Similarly, based on eight trials (22,125 participants), there was no evidence that anticoagulants reduced the odds of being dead or dependent at the end of follow up (OR 0.99; 95% CI 0.93 to 1.04). Although anticoagulant therapy was associated with fewer recurrent ischaemic strokes (OR 0.76; 95% CI 0.65 to 0.88), it was also associated with an increase in symptomatic intracranial haemorrhages (OR 2.55; 95% CI 1.95 to 3.33). Similarly, anticoagulants reduced the frequency of pulmonary emboli (OR 0.60; 95% CI 0.44 to 0.81), but this benefit was offset by an increase in extracranial haemorrhages (OR 2.99; 95% CI 2.24 to 3.99). Authors' conclusions Since the last version of the review, neither of the two new relevant studies have provided additional information to change the conclusions. In patients with acute ischaemic stroke, immediate anticoagulant therapy is not associated with net short or long-term benefit. Treatment with anticoagulants reduced recurrent stroke, deep vein thrombosis and pulmonary embolism, but increased bleeding risk. The data do not support the routine use of any the currently available anticoagulants in acute ischaemic stroke.

Programmed Death-Ligand 1 Immunohistochemistry Testing: A Review of Analytical Assays and Clinical Implementation in Non-Small-Cell Lung Cancer.

Abstract: Purpose Three programmed death-1/programmed death-ligand 1 (PD-L1) inhibitors are currently approved for treatment of non-small-cell lung cancer (NSCLC). Treatment with pembrolizumab in NSCLC requires PD-L1 immunohistochemistry (IHC) testing. Nivolumab and atezolizumab are approved without PD-L1 testing, though US Food and Drug Administration-cleared complementary PD-L1 tests are available for both. PD-L1 IHC assays used to assess PD-L1 expression in patients treated with programmed death-1/PD-L1 inhibitors in clinical trials include PD-L1 IHC 28-8 pharmDx (28-8), PD-L1 IHC 22C3 pharmDx (22C3), Ventana PD-L1 SP142 (SP142), and Ventana PD-L1 SP263 (SP263). Differences in antibodies and IHC platforms have raised questions about comparability among these assays and their diagnostic use. This review provides practical information to help physicians and pathologists understand analytical features and comparability of various PD-L1 IHC assays and their diagnostic use. Methods We reviewed and summarized published or otherwise reported studies (January 2016 to January 2017) on clinical trial and laboratory-developed PD-L1 IHC assays (LDAs). Studies assessing the effect of diagnostic methods on PD-L1 expression levels were analyzed to address practical issues related to tissue samples used for testing. Results High concordance and interobserver reproducibility were observed with the 28-8, 22C3, and SP263 clinical trial assays for PD-L1 expression on tumor cell membranes, whereas lower PD-L1 expression was detected with SP142. Immune-cell PD-L1 expression was variable and interobserver concordance was poor. Inter- and intratumoral heterogeneity had variable effects on PD-L1 expression. Concordance among LDAs was variable. Conclusion High concordance among 28-8, 22C3, and SP263 when assessing PD-L1 expression on tumor cell membranes suggests possible interchangeability of their clinical use for NSCLC but not for assessment of PD-L1 expression on immune cells. Development of LDAs requires stringent standardization before their recommendation for routine clinical use.

Cohort study examining tamoxifen adherence and its relationship to mortality in women with breast cancer.

Abstract: Increasing duration of tamoxifen therapy improves survival in women with breast cancer but the impact of adherence to tamoxifen on mortality is unclear. This study investigated whether women prescribed tamoxifen after surgery for breast cancer adhered to their prescription and whether adherence influenced survival. A retrospective cohort study of all women with incident breast cancer in the Tayside region of Scotland between 1993 and 2002 was linked to encashed prescription records to calculate adherence to tamoxifen. Survival analysis was used to determine the effect of adherence on all-cause mortality. In all 2080 patients formed the study cohort with 1633 (79%) prescribed tamoxifen. The median duration of use was 2.42 years (IQR=1.04–4.89 years). Longer duration was associated with better survival but this varied over time. The hazard ratio for mortality in relation to duration at 2.4 years was 0.85, 95% CI=0.83–0.87. Median adherence to tamoxifen was 93% (interquartile range=84–100%). Adherence <80% was associated with poorer survival, hazard ratio 1.10, 95% CI=1.001–1.21. Persistence with tamoxifen was modest with only 49% continuing therapy for 5 years of those followed up for 5 years or more. Increased duration of tamoxifen reduces the risk of death, although one in two women do not complete the recommended 5-year course of treatment. A significant proportion of women have low adherence to tamoxifen and are at increased risk of death.

Refining the accuracy of validated target identification through coding variant fine-mapping in type 2 diabetes

Abstract: We aggregated coding variant data for 81,412 type 2 diabetes cases and 370,832 controls of diverse ancestry, identifying 40 coding variant association signals (P < 2.2 × 10−7); of these, 16 map outside known risk-associated loci. We make two important observations. First, only five of these signals are driven by low-frequency variants: even for these, effect sizes are modest (odds ratio ≤1.29). Second, when we used large-scale genome-wide association data to fine-map the associated variants in their regional context, accounting for the global enrichment of complex trait associations in coding sequence, compelling evidence for coding variant causality was obtained for only 16 signals. At 13 others, the associated coding variants clearly represent ‘false leads’ with potential to generate erroneous mechanistic inference. Coding variant associations offer a direct route to biological insight for complex diseases and identification of validated therapeutic targets; however, appropriate mechanistic inference requires careful specification of their causal contribution to disease predisposition.

Inhibition of Escherichia coli growth by acetic acid: a problem with methionine biosynthesis and homocysteine toxicity.

Abstract: The mechanism by which methionine relieves the growth inhibition of Escherichia coli K-12 that is caused by organic weak acid food preservatives was investigated. In the presence of 8 mM acetate the specific growth rate of E. coli Frag1 (in MacIlvaine's minimal medium pH 6.0) is reduced by 50%. Addition of methionine restores growth to 80% of that observed in untreated controls. Similar relief was seen with cultures treated with either benzoate or propionate. Mutants with an elevated intracellular methionine pool were almost completely resistant to the inhibitory effects of acetate, suggesting that the methionine pool becomes limiting for growth in acetate-treated cells. Measurement of the intracellular concentrations of pathway intermediates revealed that the homocysteine pool is increased dramatically in acetate-treated cells, suggesting that acetate inhibits a biosynthetic step downstream from this intermediate. Supplementation of the medium with homocysteine inhibits the growth of E. coli cells. Acetate inhibition of growth arises from the depletion of the intracellular methionine pool with the concomitant accumulation of the toxic intermediate homocysteine and this augments the effect of lowering cytoplasmic pH.