283 research outputs found
Aldosterone Antagonists in Monotherapy Are Protective against Streptozotocin-Induced Diabetic Nephropathy in Rats
Angiotensin converting enzyme inhibitors (ACEi) and angiotensin II receptor blockers (ARB) are the standard clinical therapy of diabetic nephropathy (DN), while aldosterone antagonists are only used as adjuncts. Previously in experimental DN we showed that Na/K ATPase (NKA) is mislocated and angiotensin II leads to superimposed renal progression. Here we investigated the monotherapeutic effect of aldosterone blockers on the progression of DN and renal NKA alteration in comparison to ACEi and ARBs. Streptozotocin-diabetic rats developing DN were treated with aldosterone antagonists; ACEi and ARB. Renal function, morphology, protein level and tubular localization of NKA were analyzed. To evaluate the effect of high glucose per se; HK-2 proximal tubular cells were cultured in normal or high concentration of glucose and treated with the same agents. Aldosterone antagonists were the most effective in ameliorating functional and structural kidney damage and they normalized diabetes induced bradycardia and weight loss. Aldosterone blockers also prevented hyperglycemia and diabetes induced increase in NKA protein level and enzyme mislocation. A monotherapy with aldosterone antagonists might be as, or more effective than ACEi or ARBs in the prevention of STZ-induced DN. Furthermore the alteration of the NKA could represent a novel pathophysiological feature of DN and might serve as an additional target of aldosterone blockers
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Competing Risks of Cardiovascular Versus Noncardiovascular Death During Long‐Term Follow‐Up After Acute Coronary Syndromes
Background: Understanding the relative risk of cardiovascular versus noncardiovascular death is important for designing clinical trials. These risks may differ depending on patient age, sex, and type of acute coronary syndrome (ACS). Methods and Results: IMPROVE‐IT (Improved Reduction of Outcomes: Vytorin Efficacy International Trial) was a randomized controlled trial of simvastatin plus either ezetimibe or placebo following stabilized ACS. Cause of death was adjudicated by an independent committee. We compared the cumulative incidence of cardiovascular and noncardiovascular death for patients with unstable angina/non‐ST‐segment elevation myocardial infarction (UA/NSTEMI) and ST‐segment elevation myocardial infarction (STEMI), in those <65 and ≥65 years old, and males and females, over 7 years of follow‐up. Of 18 131 patients, the presenting event was STEMI for 5190 (29%) and UA/NSTEMI for 12 941 (71%); 10 173 (56%) patients were <65 years old and 7971 (44%) were ≥65 years old at presentation. UA/NSTEMI patients were older than STEMI patients, with more cardiovascular and noncardiovascular risk factors. In STEMI patients, the cumulative incidence of cardiovascular death was higher for ∼4 years following the index event, after which noncardiovascular death predominated. In UA/NSTEMI patients, the cumulative incidence of cardiovascular death remained higher than noncardiovascular death over the full follow‐up period. Patients ≥65 years old and <65 years old had a higher incidence of cardiovascular death than noncardiovascular death over the entirety of follow‐up. Female patients had a higher incidence of cardiovascular death than noncardiovascular death for ∼6 years following the index event; male patients had a higher incidence of cardiovascular death than noncardiovascular death over the entirety of follow‐up. Conclusions: Among post‐ACS patients enrolled in a long‐term clinical trial, the relative incidence of cardiovascular and noncardiovascular death differed based on type of ACS presentation and sex, but not age. These findings further delineate long‐term prognosis after ACS and should inform the design of future cardiovascular outcomes trials
Effectiveness of measles vaccination and vitamin A treatment
Background The current strategy utilized by WHO/United Nations Children's Fund (UNICEF) to reach the Global Immunization Vision and Strategy 2010 measles reduction goal includes increasing coverage of measles vaccine, vitamin A treatment and supplementation in addition to offering two doses of vaccine to all children
Congenital rubella syndrome and autism spectrum disorder prevented by rubella vaccination - United States, 2001-2010
<p>Abstract</p> <p>Background</p> <p>Congenital rubella syndrome (CRS) is associated with several negative outcomes, including autism spectrum disorders (ASDs). The objective of this study was to estimate the numbers of CRS and ASD cases prevented by rubella vaccination in the United States from 2001 through 2010.</p> <p>Methods</p> <p>Prevention estimates were calculated through simple mathematical modeling, with values of model parameters determined from published literature. Model parameters included pre-vaccine era CRS incidence, vaccine era CRS incidence, the number of live births per year, and the percentage of CRS cases presenting with an ASD.</p> <p>Results</p> <p>Based on our estimates, 16,600 CRS cases (range: 8300-62,250) were prevented by rubella vaccination from 2001 through 2010 in the United States. An estimated 1228 ASD cases were prevented by rubella vaccination in the United States during this time period. Simulating a slight expansion in ASD diagnostic criteria in recent decades, we estimate that a minimum of 830 ASD cases and a maximum of 6225 ASD cases were prevented.</p> <p>Conclusions</p> <p>We estimate that rubella vaccination prevented substantial numbers of CRS and ASD cases in the United States from 2001 through 2010. These findings provide additional incentive to maintain high measles-mumps-rubella (MMR) vaccination coverage.</p
ACE2-Mediated Reduction of Oxidative Stress in the Central Nervous System Is Associated with Improvement of Autonomic Function
Oxidative stress in the central nervous system mediates the increase in sympathetic tone that precedes the development of hypertension. We hypothesized that by transforming Angiotensin-II (AngII) into Ang-(1–7), ACE2 might reduce AngII-mediated oxidative stress in the brain and prevent autonomic dysfunction. To test this hypothesis, a relationship between ACE2 and oxidative stress was first confirmed in a mouse neuroblastoma cell line (Neuro2A cells) treated with AngII and infected with Ad-hACE2. ACE2 overexpression resulted in a reduction of reactive oxygen species (ROS) formation. In vivo, ACE2 knockout (ACE2−/y) mice and non-transgenic (NT) littermates were infused with AngII (10 days) and infected with Ad-hACE2 in the paraventricular nucleus (PVN). Baseline blood pressure (BP), AngII and brain ROS levels were not different between young mice (12 weeks). However, cardiac sympathetic tone, brain NADPH oxidase and SOD activities were significantly increased in ACE2−/y. Post infusion, plasma and brain AngII levels were also significantly higher in ACE2−/y, although BP was similarly increased in both genotypes. ROS formation in the PVN and RVLM was significantly higher in ACE2−/y mice following AngII infusion. Similar phenotypes, i.e. increased oxidative stress, exacerbated dysautonomia and hypertension, were also observed on baseline in mature ACE2−/y mice (48 weeks). ACE2 gene therapy to the PVN reduced AngII-mediated increase in NADPH oxidase activity and normalized cardiac dysautonomia in ACE2−/y mice. Altogether, these data indicate that ACE2 gene deletion promotes age-dependent oxidative stress, autonomic dysfunction and hypertension, while PVN-targeted ACE2 gene therapy decreases ROS formation via NADPH oxidase inhibition and improves autonomic function. Accordingly, ACE2 could represent a new target for the treatment of hypertension-associated dysautonomia and oxidative stress
ATP release via anion channels
ATP serves not only as an energy source for all cell types but as an ‘extracellular messenger-for autocrine and paracrine signalling. It is released from the cell via several different purinergic signal efflux pathways. ATP and its Mg2+ and/or H+ salts exist in anionic forms at physiological pH and may exit cells via some anion channel if the pore physically permits this. In this review we survey experimental data providing evidence for and against the release of ATP through anion channels. CFTR has long been considered a probable pathway for ATP release in airway epithelium and other types of cells expressing this protein, although non-CFTR ATP currents have also been observed. Volume-sensitive outwardly rectifying (VSOR) chloride channels are found in virtually all cell types and can physically accommodate or even permeate ATP4- in certain experimental conditions. However, pharmacological studies are controversial and argue against the actual involvement of the VSOR channel in significant release of ATP. A large-conductance anion channel whose open probability exhibits a bell-shaped voltage dependence is also ubiquitously expressed and represents a putative pathway for ATP release. This channel, called a maxi-anion channel, has a wide nanoscopic pore suitable for nucleotide transport and possesses an ATP-binding site in the middle of the pore lumen to facilitate the passage of the nucleotide. The maxi-anion channel conducts ATP and displays a pharmacological profile similar to that of ATP release in response to osmotic, ischemic, hypoxic and salt stresses. The relation of some other channels and transporters to the regulated release of ATP is also discussed
Virtual Patients and Sensitivity Analysis of the Guyton Model of Blood Pressure Regulation: Towards Individualized Models of Whole-Body Physiology
Mathematical models that integrate multi-scale physiological data can offer insight into physiological and pathophysiological function, and may eventually assist in individualized predictive medicine. We present a methodology for performing systematic analyses of multi-parameter interactions in such complex, multi-scale models. Human physiology models are often based on or inspired by Arthur Guyton's whole-body circulatory regulation model. Despite the significance of this model, it has not been the subject of a systematic and comprehensive sensitivity study. Therefore, we use this model as a case study for our methodology. Our analysis of the Guyton model reveals how the multitude of model parameters combine to affect the model dynamics, and how interesting combinations of parameters may be identified. It also includes a “virtual population” from which “virtual individuals” can be chosen, on the basis of exhibiting conditions similar to those of a real-world patient. This lays the groundwork for using the Guyton model for in silico exploration of pathophysiological states and treatment strategies. The results presented here illustrate several potential uses for the entire dataset of sensitivity results and the “virtual individuals” that we have generated, which are included in the supplementary material. More generally, the presented methodology is applicable to modern, more complex multi-scale physiological models
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