2,719 research outputs found

    2-Methoxyoestradiol-3,17-O,O-bis-sulphamate and 2-deoxy-D-glucose in combination: a potential treatment for breast and prostate cancer

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    Drug combination therapy is a key strategy to improve treatment efficacy and survival of cancer patients. In this study the effects of combining 2-methoxyoestradiol-3,17-O,O-bis-sulphamate (STX140), a microtubule disruptor, with 2-deoxy-D-glucose (2DG) were assessed in MCF-7 (breast) and LNCaP (prostate) xenograft models in vivo. In mice bearing MCF-7 xenografts, daily p.o. administration of STX140 (5 mg kg−1) resulted in a 46% (P<0.05) reduction of tumour volume. However, the combination of STX140 (5 mg kg−1 p.o.) and 2DG (2 g kg−1 i.p.) reduced tumour volume by 76% (P<0.001). 2-Methoxyoestradiol-3,17-O,O-bis-sulphamate also reduced tumour vessel density. 2-Deoxy-D-glucose alone had no significant effect on tumour volume or vessel density. A similar benefit of the combination treatment was observed in the LNCaP prostate xenograft model. In vitro the degree of inhibition of cell proliferation by STX140 was unaffected by oxygen concentrations. In contrast, the inhibition of proliferation by 2DG was enhanced under hypoxia by 20 and 25% in MCF-7 and LNCaP cells, respectively. The combination of STX140 and 2DG in LNCaP cells under normoxia or hypoxia inhibited proliferation to a greater extent than either compound alone. These results suggest that the antiangiogenic and microtubule disruption activities of STX140 may make tumours more susceptible to inhibition of glycolysis by 2DG. This is the first study to show the benefit of combining a microtubule disruptor with 2DG in the two most common solid tumours

    Characterization of complex networks: A survey of measurements

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    Each complex network (or class of networks) presents specific topological features which characterize its connectivity and highly influence the dynamics of processes executed on the network. The analysis, discrimination, and synthesis of complex networks therefore rely on the use of measurements capable of expressing the most relevant topological features. This article presents a survey of such measurements. It includes general considerations about complex network characterization, a brief review of the principal models, and the presentation of the main existing measurements. Important related issues covered in this work comprise the representation of the evolution of complex networks in terms of trajectories in several measurement spaces, the analysis of the correlations between some of the most traditional measurements, perturbation analysis, as well as the use of multivariate statistics for feature selection and network classification. Depending on the network and the analysis task one has in mind, a specific set of features may be chosen. It is hoped that the present survey will help the proper application and interpretation of measurements.Comment: A working manuscript with 78 pages, 32 figures. Suggestions of measurements for inclusion are welcomed by the author

    Increasing diterpene yield with a modular metabolic engineering system in E. coli: comparison of MEV and MEP isoprenoid precursor pathway engineering

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    Engineering biosynthetic pathways in heterologous microbial host organisms offers an elegant approach to pathway elucidation via the incorporation of putative biosynthetic enzymes and characterization of resulting novel metabolites. Our previous work in Escherichia coli demonstrated the feasibility of a facile modular approach to engineering the production of labdane-related diterpene (20 carbon) natural products. However, yield was limited (<0.1 mg/L), presumably due to reliance on endogenous production of the isoprenoid precursors dimethylallyl diphosphate and isopentenyl diphosphate. Here, we report incorporation of either a heterologous mevalonate pathway (MEV) or enhancement of the endogenous methyl erythritol phosphate pathway (MEP) with our modular metabolic engineering system. With MEP pathway enhancement, it was found that pyruvate supplementation of rich media and simultaneous overexpression of three genes (idi, dxs, and dxr) resulted in the greatest increase in diterpene yield, indicating distributed metabolic control within this pathway. Incorporation of a heterologous MEV pathway in bioreactor grown cultures resulted in significantly higher yields than MEP pathway enhancement. We have established suitable growth conditions for diterpene production levels ranging from 10 to >100 mg/L of E. coli culture. These amounts are sufficient for nuclear magnetic resonance analyses, enabling characterization of enzymatic products and hence, pathway elucidation. Furthermore, these results represent an up to >1,000-fold improvement in diterpene production from our facile, modular platform, with MEP pathway enhancement offering a cost effective alternative with reasonable yield. Finally, we reiterate here that this modular approach is expandable and should be easily adaptable to the production of any terpenoid natural product

    30% land conservation and climate action reduces tropical extinction risk by more than 50%

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    Limiting climate change to less than 2°C is the focus of international policy under the climate convention (UNFCCC), and is essential to preventing extinctions, a focus of the Convention on Biological Diversity (CBD). The post‐2020 biodiversity framework drafted by the CBD proposes conserving 30% of both land and oceans by 2030. However, the combined impact on extinction risk of species from limiting climate change and increasing the extent of protected and conserved areas has not been assessed. Here we create conservation spatial plans to minimize extinction risk in the tropics using data on 289 219 species and modeling two future greenhouse gas concentration pathways (RCP2.6 and 8.5) while varying the extent of terrestrial protected land and conserved areas from <17% to 50%. We find that limiting climate change to 2°C and conserving 30% of terrestrial area could more than halve aggregate extinction risk compared with uncontrolled climate change and no increase in conserved area

    Gambling disorder and suicide: An overview of the associated co-morbidity and clinical characteristics

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    Context: A high prevalence of suicide and attempted suicide in relation to gambling disorder is in increasing evidence in current scientific data. The objective of this review was to explore if there was a primary correlation between psychiatric co-morbidities and gambling and/or a secondary correlation with suicide acts. Evidence Acquisition: We performed a critical analysis of the most recent papers in the scientific literature in this regard and report on the most significant findings. Results: A direct relationship between gambling and suicidality was highlighted in a number of European, American, and Asian countries. However, it was not clear whether or not gambling increased the risk of suicidal behavior. Twogeneral trends were noted. The first was that gamblers with extreme gambling behavior incurred economic losses and debts to such an extent that suicidal acts appeared to be the only solution. The second was that suicidal acts by gamblers were precipitated by interpersonal and/or working challenges, in conjunction with personality traits of impulsivity and psychiatric co-morbidities. Conclusions: A combination of impulsivity, certain psychiatric disorders, and social factors may explain the frequent occurrence of suicidal behavior in gamblers

    Characteristic Evolution and Matching

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    I review the development of numerical evolution codes for general relativity based upon the characteristic initial value problem. Progress in characteristic evolution is traced from the early stage of 1D feasibility studies to 2D axisymmetric codes that accurately simulate the oscillations and gravitational collapse of relativistic stars and to current 3D codes that provide pieces of a binary black hole spacetime. Cauchy codes have now been successful at simulating all aspects of the binary black hole problem inside an artificially constructed outer boundary. A prime application of characteristic evolution is to extend such simulations to null infinity where the waveform from the binary inspiral and merger can be unambiguously computed. This has now been accomplished by Cauchy-characteristic extraction, where data for the characteristic evolution is supplied by Cauchy data on an extraction worldtube inside the artificial outer boundary. The ultimate application of characteristic evolution is to eliminate the role of this outer boundary by constructing a global solution via Cauchy-characteristic matching. Progress in this direction is discussed.Comment: New version to appear in Living Reviews 2012. arXiv admin note: updated version of arXiv:gr-qc/050809

    Mortality in Peripheral Arterial Disease: A Comparison of Patients Managed by Vascular Specialists and General Practitioners

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    BACKGROUND: Peripheral arterial disease (PAD) is undertreated by general practitioners (GPs). However, the impact of the suboptimal clinical management is unknown. OBJECTIVE: To assess the mortality rate of PAD patients in relation to the type of physician who provides their care (GP or vascular specialist). DESIGN: Prospective study. SETTING: Primary care practice and academic vascular laboratory. PARTICIPANTS: GP patients (n = 60) were those of the Peripheral Arteriopathy and Cardiovascular Events study (PACE). Patients managed by specialists (n = 82) were consecutive subjects with established PAD who were referred to our vascular laboratory during the enrolment period of the PACE study. MEASUREMENTS: All-cause and cardiovascular mortality. RESULTS: After 32 months of follow-up, specialist management was associated with a lower rate of all-cause mortality (RR = 0.04; 95% CI 0.01–0.34; p = .003) and cardiovascular mortality (RR = 0.07; 95% CI 0.01–0.65; p = .020), after adjustment for patients’ characteristics. Specialists were more likely to use antiplatelet agents (93% vs 73%, p < .001), statins (62% vs 25%, p < .001) and beta blockers (28% vs 3%, p < .001). Survival differences between specialists and GPs disappeared once the use of pharmacotherapies was added to the proportional hazard model. The fully adjusted model showed that the use of statins was significantly associated with a reduced risk of all-cause mortality (RR = 0.02; 95% CI 0.01–0.73, p = .034) and cardiovascular mortality (RR = 0.02; 95% CI 0.01–0.71, p = .033). CONCLUSIONS: Specialist management of patients with symptomatic PAD resulted in better survival than generalist management. This effect appears to be mainly caused by the more frequent use of effective medicines by specialists

    Statin use, hyperlipidaemia, and the risk of breast cancer

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    Hydroxymethyl glutaryl coenzyme A inhibitors (‘statins’) are carcinogenic in rodents and an increased incidence of breast cancer was reported among pravastatin users in one randomised trial. We conducted a case–control study in the General Practice Research Database to evaluate the risk of breast cancer among 50- to 79-year old women treated with statins for hyperlipidaemia. Case and control women were matched by age, general practice, duration of prescription history in the General Practice Research Database, and index date. Adjusting for history of benign breast disease, body mass index, and use of hormone replacement therapy, women currently treated with statins had an estimated relative risk for breast cancer of 1.0 (95% confidence interval 0.6–1.6) compared to women without hyperlipidaemia. Untreated hyperlipidaemia was associated with an increased risk of breast cancer (estimated relative risk 1.6; 95% confidence interval 1.1–2.5). The estimated relative risk among women currently receiving only non-statin lipid-lowering drugs was similar to that of women with untreated hyperlipidaemia (1.8; 95% confidence interval 0.9–3.4). We found no evidence for an increasing trend in breast cancer risk with increasing duration of statin use (median duration 1.8 years, maximum 8.6 years)
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