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25,321 result(s) for "Rodriguez, Luis A."
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Antihypertensive drugs and risk of incident gout among patients with hypertension: population based case-control study
Objective To determine the independent associations of antihypertensive drugs with the risk of incident gout among people with hypertension.Design Nested case-control study.Setting UK general practice database, 2000-7.Participants All incident cases of gout (n=24 768) among adults aged 20-79 and a random sample of 50 000 matched controls.Main outcome measure Relative risk of incident gout associated with use of antihypertensive drugs.Results After adjusting for age, sex, body mass index, visits to the general practitioner, alcohol intake, and pertinent drugs and comorbidities, the multivariate relative risks of incident gout associated with current use of antihypertensive drugs among those with hypertension (n=29 138) were 0.87 (95% confidence interval 0.82 to 0.93) for calcium channel blockers, 0.81 (0.70 to 0.94) for losartan, 2.36 (2.21 to 2.52) for diuretics, 1.48 (1.40 to 1.57) for β blockers, 1.24 (1.17 to 1.32) for angiotensin converting enzyme inhibitors, and 1.29 (1.16 to 1.43) for non-losartan angiotensin II receptor blockers. Similar results were obtained among those without hypertension. The multivariate relative risks for the duration of use of calcium channel blockers among those with hypertension were 1.02 for less than one year, 0.88 for 1-1.9 years, and 0.75 for two or more years and for use of losartan they were 0.98, 0.87, and 0.71, respectively (both P<0.05 for trend).Conclusions Compatible with their urate lowering properties, calcium channel blockers and losartan are associated with a lower risk of incident gout among people with hypertension. By contrast, diuretics, β blockers, angiotensin converting enzyme inhibitors, and non-losartan angiotensin II receptor blockers are associated with an increased risk of gout.
Low-Dose Aspirin for the Prevention of Atherothrombosis
This review considers the role of low-dose aspirin for the prevention of atherothrombosis, discussing the molecular mechanism of action of aspirin as well as clinical and epidemiologic studies of aspirin as an antiplatelet agent, with special emphasis on the benefits and risks in different patient populations. This review considers the role of low-dose aspirin for the prevention of atherothrombosis, discussing the molecular mechanism of action of aspirin as well as clinical and epidemiologic studies of aspirin as an antiplatelet agent. Atherosclerosis, the major cause of ischemic coronary artery disease and cerebrovascular disease, is a chronic inflammatory disorder in which immune mechanisms interact with metabolic risk factors to initiate, propagate, and activate vascular lesions. 1 Arterial thrombosis, an acute complication that develops on the surface of a ruptured atheromatous plaque or as a consequence of endothelial erosion, 1 may cause myocardial infarction or ischemic stroke. Platelets are key cellular components of arterial occlusive thrombi and may participate in the development and progression of atheromatous plaques. 2 Platelets are also vital components of hemostasis, the physiologic process that arrests hemorrhage after tissue trauma and vascular . . .
Short-term physiological hypoxia potentiates the therapeutic function of mesenchymal stem cells
Background In the bone marrow, MSCs reside in a hypoxic milieu (1–5% O 2 ) that is thought to preserve their multipotent state. Typically, in vitro expansion of MSCs is performed under normoxia (~ 21% O 2 ), a process that has been shown to impair their function. Here, we evaluated the characteristics and function of MSCs cultured under hypoxia and hypothesized that, when compared to normoxia, dedicated hypoxia will augment the functional characteristics of MSCs. Methods Human and porcine bone marrow MSCs were obtained from fresh mononuclear cells. The first study evaluated MSC function following both long-term (10 days) and short-term (48 h) hypoxia (1% O 2 ) culture. In our second study, we evaluated the functional characteristics of MSC cultured under short-term 2% and 5% hypoxia. MSCs were evaluated for their metabolic activity, proliferation, viability, clonogenicity, gene expression, and secretory capacity. Results In long-term culture, common MSC surface marker expression (CD44 and CD105) dropped under hypoxia. Additionally, in long-term culture, MSCs proliferated significantly slower and provided lower yields under hypoxia. Conversely, in short-term culture, MSCs proliferated significantly faster under hypoxia. In both long-term and short-term cultures, MSC metabolic activity was significantly higher under hypoxia. Furthermore, MSCs cultured under hypoxia had upregulated expression of VEGF with concomitant downregulation of HMGB1 and the apoptotic genes BCL-2 and CASP3. Finally, in both hypoxia cultures, the pro-inflammatory cytokine, IL-8, was suppressed, while levels of the anti-inflammatories, IL-1ra and GM-CSF, were elevated in short-term hypoxia only. Conclusions In this study, we demonstrate that hypoxia augments the therapeutic characteristics of both porcine and human MSCs. Yet, short-term 2% hypoxia offers the greatest benefit overall, exemplified by the increase in proliferation, self-renewing capacity, and modulation of key genes and the inflammatory milieu as compared to normoxia. These data are important for generating robust MSCs with augmented function for clinical applications.
Wide Bandwidth Vibration Energy Harvester with Embedded Transverse Movable Mass
One of the biggest challenges associated with vibration energy harvesters is their limited bandwidth, which reduces their effectiveness when utilized for Internet of Things applications. This paper presents a novel method of increasing the bandwidth of a cantilever beam by using an embedded transverse out-of-plane movable mass, which continuously changes the resonant frequency due to mass change and non-linear dynamic impact forces. The concept was investigated through experimentation of a movable mass, in the form of a solid sphere, that was embedded within a stationary proof mass with hollow cylindrical chambers. As the cantilever oscillated, it caused the movable mass to move out-of-plane, thus effectively altering the overall effective mass of the system during operation. This concept combined high bandwidth non-linear dynamics from the movable mass with the high power linear dynamics from the stationary proof mass. This paper experimentally investigated the frequency and power effects of acceleration, the amount of movable mass, the density of the mass, and the size of the movable mass. The results demonstrated that the bandwidth can be significantly increased from 1.5 Hz to >40 Hz with a transverse movable mass, while maintaining high power output. Dense movable masses are better for high acceleration, low frequency applications, whereas lower density masses are better for low acceleration applications.
Cryopreserved mesenchymal stem cells regain functional potency following a 24-h acclimation period
Background Mesenchymal stem cells (MSCs) are attractive cell-therapy candidates. Despite their popularity and promise, there is no uniform method of preparation of MSCs. Typically, cells are cryopreserved in liquid nitrogen, thawed, and subsequently administered to a patient with little to no information on their function post-thaw. We hypothesized that a short acclimation period post-thaw will facilitate the recovery of MSC’s functional potency. Methods Human bone-marrow-derived MSCs were divided into 3 groups: FC (fresh cells; from existing culture); TT (thawed + time; acclimated for 24 h post-thaw); and FT (freshly thawed; thawed and immediately used). The 3 groups were analyzed for their cellular and functional potency. Results Phenotypic analysis demonstrated a decrease in CD44 and CD105 surface markers in FT MSCs, with no change in the other two groups. All MSCs were able to differentiate down the osteogenic and chondrogenic lineages. In FT cells, metabolic activity and apoptosis was significantly increased with concomitant decrease in cell proliferation; clonogenic capacity; and key regenerative genes. Following 24-h acclimation, apoptosis was significantly reduced in TT cells with a concomitant upregulation in angiogenic and anti-inflammatory genes. While all MSCs significantly arrested T-cell proliferation, the TT MSCs were significantly more potent. Similarly, although all MSCs maintained their anti-inflammatory properties, IFN-γ secretion was significantly diminished in FT cells. Conclusions These data demonstrate that FT MSCs maintain their multipotent differentiation capacity, immunomodulatory function, and anti-inflammatory properties; yet, various aspects of cell characteristics and function are deleteriously affected by cryopreservation. Importantly, a 24-h acclimation period ‘reactivates’ thawed cells to recover their diminished stem-cell function.
Targeting FGFR4 Inhibits Hepatocellular Carcinoma in Preclinical Mouse Models
The fibroblast growth factor (FGF)-FGF receptor (FGFR) signaling system plays critical roles in a variety of normal developmental and physiological processes. It is also well documented that dysregulation of FGF-FGFR signaling may have important roles in tumor development and progression. The FGFR4-FGF19 signaling axis has been implicated in the development of hepatocellular carcinomas (HCCs) in mice, and potentially in humans. In this study, we demonstrate that FGFR4 is required for hepatocarcinogenesis; the progeny of FGF19 transgenic mice, which have previously been shown to develop HCCs, bred with FGFR4 knockout mice fail to develop liver tumors. To further test the importance of FGFR4 in HCC, we developed a blocking anti-FGFR4 monoclonal antibody (LD1). LD1 inhibited: 1) FGF1 and FGF19 binding to FGFR4, 2) FGFR4-mediated signaling, colony formation, and proliferation in vitro, and 3) tumor growth in a preclinical model of liver cancer in vivo. Finally, we show that FGFR4 expression is elevated in several types of cancer, including liver cancer, as compared to normal tissues. These findings suggest a modulatory role for FGFR4 in the development and progression of hepatocellular carcinoma and that FGFR4 may be an important and novel therapeutic target in treating this disease.
Statins and Risk of Diabetes: An analysis of electronic medical records to evaluate possible bias due to differential survival
Two meta-analyses of randomized trials of statins found increased risk of type 2 diabetes. One possible explanation is bias due to differential survival when patients who are at higher risk of diabetes survive longer under statin treatment. We used electronic medical records from 500 general practices in the U.K. and included data from 285,864 men and women aged 50-84 years from January 2000 to December 2010. We emulated the design and analysis of a hypothetical randomized trial of statins, estimated the observational analog of the intention-to-treat effect, and adjusted for differential survival bias using inverse-probability weighting. During 1.2 million person-years of follow-up, there were 13,455 cases of type 2 diabetes and 8,932 deaths. Statin initiation was associated with increased risk of type 2 diabetes. The hazard ratio (95% CI) of diabetes was 1.45 (1.39-1.50) before adjusting for potential confounders and 1.14 (1.10-1.19) after adjustment. Adjusting for differential survival did not change the estimates. Initiating atorvastatin and simvastatin was associated with increased risk of type 2 diabetes. In this sample of the general population, statin therapy was associated with 14% increased risk of type 2 diabetes. Differential survival did not explain this increased risk.
The Dimensions of School Discipline: Toward a Comprehensive Framework for Measuring Discipline Patterns and Outcomes in Schools
The school discipline literature has expanded rapidly in recent decades, yet the conceptualization and measurement of school discipline patterns remains overlooked. In this paper, we present a comprehensive analytic framework to examine school discipline patterns that encompasses school-level metrics that capture the prevalence and disparity in exclusionary discipline and regression-based approaches that examine the likelihood that students experience exclusionary discipline. We apply the framework to New York City and, based on school-level metrics, find that Black students have the highest prevalence and the highest disproportionality. Results from regression models affirm that Black students are most likely to receive office discipline referrals and suspensions and experience differential processing of suspensions for similar categories of infractions. The findings illustrate the nuances of the disciplinary process in schools and inform the consideration of a range of available analytic tools that educational stakeholders may employ to better measure and understand exclusionary discipline.
New use of low-dose aspirin and risk of colorectal cancer by stage at diagnosis: a nested case–control study in UK general practice
Background Evidence from clinical trial populations suggests low-dose aspirin reduces the risk of colorectal cancer (CRC). Part of this reduction in risk might be due to protection against metastatic disease. Methods We investigated the risk of CRC among new-users of low-dose aspirin (75–300 mg), including risk by stage at diagnosis. Using The Health Improvement Network, we conducted a cohort study with nested case–control analysis. Two cohorts ( N  = 170,336 each) aged 40–89 years from 2000 to 2009 and free of cancer were identified: i) new-users of low-dose aspirin, ii) non-users of low-dose aspirin, at start of follow-up, matched by age, sex and previous primary care practitioner visits. Patients were followed for up to 12 years to identify incident CRC. 10,000 frequency-matched controls were selected by incidence density sampling where the odds ratio is an unbiased estimator of the incidence rate ratio (RR). RRs with 95% confidence intervals were calculated. Low-dose aspirin use was classified ‘as-treated’ independent from baseline exposure status to account for changes in exposure during follow-up. Results Current users of low-dose aspirin (use on the index date or in the previous 90 days) had a significantly reduced risk of CRC, RR 0.66 (95% CI 0.60–0.74). The reduction in risk was apparent across all age groups, and was unrelated to dose, indication, gender, CRC location or case-fatality status. Reduced risks occurred throughout treatment duration and with all low-dose aspirin doses. RRs by aspirin indication were 0.71 (0·63–0·79) and 0.60 (0.53–0.68) for primary and secondary cardiovascular protection, respectively. Among cases with staging information ( n  = 1421), RRs for current use of low-dose aspirin were 0.94 (0.66–1.33) for Dukes Stage A CRC, 0.54 (0.42–0.68) for Dukes B, 0.71 (0.56–0.91) for Dukes C, and 0.60 (0.48–0.74) for Dukes D. After 5 years’ therapy, the RR for Dukes Stage A CRC was 0.53 (0.24–1.19). Conclusions Patients starting low-dose aspirin therapy have a reduced risk of Stages B–D CRC, suggesting a role for low-dose aspirin in the progression of established CRC; a substantial reduction in the risk of Dukes A CRC may occur after 5 years’ therapy.
Effect of Antisecretory Drugs and Nitrates on the Risk of Ulcer Bleeding Associated With Nonsteroidal Anti-Inflammatory Drugs, Antiplatelet Agents, and Anticoagulants
After the withdrawal of some cyclooxygenase-2 (COX-2) selective inhibitors, traditional nonsteroidal anti-inflammatory drug (NSAID) use has increased, but without additional prevention strategies against upper gastrointestinal (GI) complications in many cases. Here, we report the effect of antisecretory drugs and nitrates on the risk of upper GI peptic ulcer bleeding (UGIB) associated with nonselective NSAIDs, aspirin, antiplatelet agents, and anticoagulants. This case-control study matched 2,777 consecutive patients with UGIB (confirmed by endoscopy) with 5,532 controls (2:1). Adjusted relative risks (RR) of UGIB are reported. Proton pump inhibitors (PPIs) (RR 0.33, 95% confidence interval [CI] 0.27-0.39), H2-receptor antagonists (H2-RAs) (RR 0.65, 95% CI 0.50-0.85), and nitrates (RR 0.52, 95% CI 0.38-0.70) reduced UGIB risk. PPI use was associated with greater reductions among both traditional NSAID (RR 0.13, 95% CI 0.09-0.19 vs RR 0.30, 95% CI 0.17-0.53 with H2-RAs; RR 0.48, 95% CI 0.19-1.24 with nitrates) and low-dose aspirin users (RR 0.32, 95% CI 0.22-0.51 vs RR 0.40, 95% CI 0.19-0.73 with H2-RA; RR 0.69, 95% CI 0.36-1.04 with nitrates), and among patients taking clopidogrel (RR 0.19, 95% CI 0.07-0.49). For patients taking anticoagulants, use of nitrates, H2-RA, or PPIs was not associated with a significant effect on UGIB risk. Antisecretory agent or nitrate treatment is associated with reduced UGIB RR in patients taking NSAID or aspirin. Only PPI therapy was associated with a marked, consistent risk reduction among patients receiving all types of agents (including nonaspirin antiplatelet agents). Protection was not apparent in patients taking anticoagulants.