75 research outputs found

    Toward a Multi-Scale Computational Model of Arterial Adaptation in Hypertension: Verification of a Multi-Cell Agent Based Model

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    Agent-based models (ABMs) represent a novel approach to study and simulate complex mechano chemo-biological responses at the cellular level. Such models have been used to simulate a variety of emergent responses in the vasculature, including angiogenesis and vasculogenesis. Although not used previously to study large vessel adaptations, we submit that ABMs will prove equally useful in such studies when combined with well-established continuum models to form multi-scale models of tissue-level phenomena. In order to couple agent-based and continuum models, however, there is a need to ensure that each model faithfully represents the best data available at the relevant scale and that there is consistency between models under baseline conditions. Toward this end, we describe the development and verification of an ABM of endothelial and smooth muscle cell responses to mechanical stimuli in a large artery. A refined rule-set is proposed based on a broad literature search, a new scoring system for assigning confidence in the rules, and a parameter sensitivity study. To illustrate the utility of these new methods for rule selection, as well as the consistency achieved with continuum-level models, we simulate the behavior of a mouse aorta during homeostasis and in response to both transient and sustained increases in pressure. The simulated responses depend on the altered cellular production of seven key mitogenic, synthetic, and proteolytic biomolecules, which in turn control the turnover of intramural cells and extracellular matrix. These events are responsible for gross changes in vessel wall morphology. This new ABM is shown to be appropriately stable under homeostatic conditions, insensitive to transient elevations in blood pressure, and responsive to increased intramural wall stress in hypertension

    Impacts of the COVID-19 pandemic on access to HIV and reproductive health care among women living with HIV (WLHIV) in Western Kenya: A mixed methods analysis

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    Results: We analyzed 1,402 surveys and 15 in-depth interviews. Many (32%) CL participants reported greater difficulty refilling medications and a minority (14%) reported greater difficulty accessing HIV care during the pandemic. Most (99%) Opt4Mamas participants reported no difficulty refilling medications or accessing HIV/pregnancy care. Among the CL participants, older women were less likely (aOR = 0.95, 95% CI: 0.92–0.98) and women with more children were more likely (aOR = 1.13, 95% CI: 1.00–1.28) to report difficulty refilling medications. Only 2% of CL participants reported greater difficulty managing FP and most (95%) reported no change in likelihood of using FP or desire to get pregnant. Qualitative analysis revealed three major themes: (1) adverse organizational/economic implications of the pandemic, (2) increased importance of pregnancy prevention during the pandemic, and (3) fear of contracting COVID-19

    AD51B in Familial Breast Cancer

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    Common variation on 14q24.1, close to RAD51B, has been associated with breast cancer: rs999737 and rs2588809 with the risk of female breast cancer and rs1314913 with the risk of male breast cancer. The aim of this study was to investigate the role of RAD51B variants in breast cancer predisposition, particularly in the context of familial breast cancer in Finland. We sequenced the coding region of RAD51B in 168 Finnish breast cancer patients from the Helsinki region for identification of possible recurrent founder mutations. In addition, we studied the known rs999737, rs2588809, and rs1314913 SNPs and RAD51B haplotypes in 44,791 breast cancer cases and 43,583 controls from 40 studies participating in the Breast Cancer Association Consortium (BCAC) that were genotyped on a custom chip (iCOGS). We identified one putatively pathogenic missense mutation c.541C>T among the Finnish cancer patients and subsequently genotyped the mutation in additional breast cancer cases (n = 5259) and population controls (n = 3586) from Finland and Belarus. No significant association with breast cancer risk was seen in the meta-analysis of the Finnish datasets or in the large BCAC dataset. The association with previously identified risk variants rs999737, rs2588809, and rs1314913 was replicated among all breast cancer cases and also among familial cases in the BCAC dataset. The most significant association was observed for the haplotype carrying the risk-alleles of all the three SNPs both among all cases (odds ratio (OR): 1.15, 95% confidence interval (CI): 1.11–1.19, P = 8.88 x 10−16) and among familial cases (OR: 1.24, 95% CI: 1.16–1.32, P = 6.19 x 10−11), compared to the haplotype with the respective protective alleles. Our results suggest that loss-of-function mutations in RAD51B are rare, but common variation at the RAD51B region is significantly associated with familial breast cancer risk

    Contribution of Maternal Antiretroviral Therapy and Breastfeeding to 24-Month Survival in Human Immunodeficiency Virus-Exposed Uninfected Children: An Individual Pooled Analysis of African and Asian Studies

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    Background: Increasing numbers of HIV-infected pregnant women receive antiretroviral therapy (ART) to prevent mother-to-child transmission (PMTCT). Studies suggested that HIV-exposed uninfected (HEU) children face higher mortality than HIV-unexposed children, but evidence mostly relates to the pre-ART era, breastfeeding of limited duration and considerable maternal mortality. Maternal ART and prolonged breastfeeding under cover of ART may improve survival, although this has not been reliably quantified. Methods: Individual data on 19,219 HEU children from 21 PMTCT trials/cohorts undertaken 1995-2015 in Africa and Asia were pooled and the association between 24-month mortality and maternal/infant factors quantified using random-effects Cox proportional hazards models accounting for between-study heterogeneity. Adjusted attributable fractions of risks computed using the predict function in the R package "frailtypack" estimate the relative contribution of risk factors to overall mortality in HEU children. Results: Cumulative incidence of death was 5.5% (95%CI: 5.1-5.9) by age 24 months. Low birth weight (LBW<2500g, adjusted Hazard Ratio (aHR: 2.9), no breastfeeding (aHR: 2.5) and maternal death (aHR: 11.1) were significantly associated with increased mortality. Maternal ART (aHR: 0.5) was significantly associated with lower mortality. At population level, LBW accounted for 16.2% of child deaths by 24 months, never breastfeeding for 10.8%, mother not receiving ART for 45.6%, and maternal death for 4.3%; these factors combined explained 63.6% of deaths by age 24 months. Conclusion: Survival of HEU children could be substantially improved if public health strategies provided all mothers living with HIV with ART and supported optimal infant feeding and care for LBW neonates

    Effects of Anacetrapib in Patients with Atherosclerotic Vascular Disease

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    BACKGROUND: Patients with atherosclerotic vascular disease remain at high risk for cardiovascular events despite effective statin-based treatment of low-density lipoprotein (LDL) cholesterol levels. The inhibition of cholesteryl ester transfer protein (CETP) by anacetrapib reduces LDL cholesterol levels and increases high-density lipoprotein (HDL) cholesterol levels. However, trials of other CETP inhibitors have shown neutral or adverse effects on cardiovascular outcomes. METHODS: We conducted a randomized, double-blind, placebo-controlled trial involving 30,449 adults with atherosclerotic vascular disease who were receiving intensive atorvastatin therapy and who had a mean LDL cholesterol level of 61 mg per deciliter (1.58 mmol per liter), a mean non-HDL cholesterol level of 92 mg per deciliter (2.38 mmol per liter), and a mean HDL cholesterol level of 40 mg per deciliter (1.03 mmol per liter). The patients were assigned to receive either 100 mg of anacetrapib once daily (15,225 patients) or matching placebo (15,224 patients). The primary outcome was the first major coronary event, a composite of coronary death, myocardial infarction, or coronary revascularization. RESULTS: During the median follow-up period of 4.1 years, the primary outcome occurred in significantly fewer patients in the anacetrapib group than in the placebo group (1640 of 15,225 patients [10.8%] vs. 1803 of 15,224 patients [11.8%]; rate ratio, 0.91; 95% confidence interval, 0.85 to 0.97; P=0.004). The relative difference in risk was similar across multiple prespecified subgroups. At the trial midpoint, the mean level of HDL cholesterol was higher by 43 mg per deciliter (1.12 mmol per liter) in the anacetrapib group than in the placebo group (a relative difference of 104%), and the mean level of non-HDL cholesterol was lower by 17 mg per deciliter (0.44 mmol per liter), a relative difference of -18%. There were no significant between-group differences in the risk of death, cancer, or other serious adverse events. CONCLUSIONS: Among patients with atherosclerotic vascular disease who were receiving intensive statin therapy, the use of anacetrapib resulted in a lower incidence of major coronary events than the use of placebo. (Funded by Merck and others; Current Controlled Trials number, ISRCTN48678192 ; ClinicalTrials.gov number, NCT01252953 ; and EudraCT number, 2010-023467-18 .)

    Our Practice Newsletter : By Pharmacists For Pharmacists, issue 3

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    In the feature article this issue of Our Practice, we dive into the flow of a typical pharmacist consultation, from establishing patient priorities, gathering information, identifying and prioritizing drug therapy problems (DTPs), scheduling follow-up appointments, and finally, communicating with other healthcare providers such as physicians and nurse practitioners the patient’s circle of care. The case study this issue explores the efficacy and safety profile of SGLT2 inhibitors in the treatment of diabetes.Pharmaceutical Sciences, Faculty ofUnreviewedOthe

    Tridisma: An EU program for utilizing acoustics for measuring suspended sediment processes [abstract of paper presented at Joint 140th Meeting ASA/NOISE-CON 2000]

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    In this paper the application of high-frequency acoustic remote sensing is discussed with respect to the development of an instrument capable of resolving the dynamics of the benthic boundary layer, in response to the interaction of waves and currents, using sound backscattered by the sediments entrained by the flow. Within the TRIDISMA project an acoustic instrument has been developed which combines three distinct approaches to the analysis of backscattered signals in order to extract information on flow structure and the response of the sediment bed to the overlying flow. The TRIDISMA instrument combines pulse coherent Doppler and acoustic cross-correlation techniques to the problem of extracting profiles of velocity, while the amplitude of the backscattered signal measured at three frequencies is used to investigate the response of the suspension field in terms of both size and concentration profiles. In the present paper we describe the hardware and software architecture of the prototype instrument and demonstrate the systems capabilities with results obtained from flume studies of waves, currents, and combined flows. <br/
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