Androgen receptor independent cardiovascular action of the antiandrogen flutamide

We have previously shown that flutamide (specific antagonist of the androgen receptor) has antihypertensive effects. In the present study we examined the mechanisms of flutamide action in the vasculature. The vascular effects of flutamide were assayed in aortae isolated from male or female Sprague-Dawley rats and from rats or mice lacking a functional androgen receptor ( tfm, testicular feminization mutation). The effect of flutamide on coronary flow was tested in isolated hearts. In addition, male hypertensive rats with tfm mutation were treated with flutamide, and blood pressure was monitored. Flutamide induced a relaxation of rat aortae from all the strains used (maximum relaxation at 10 microM: 51.3+/-5.2% of phenylephrine contraction) and increased the coronary flow. The aortic relaxation to flutamide was abolished by endothelium removal, or by inhibition of nitric oxide synthase, guanylyl cyclase, and tyrosine kinase but not by calmodulin inhibition. Flutamide treatment attenuated the development of hypertension in mouse renin transgenic rats with the tfm mutation. Flutamide produces direct vasodilation by inducing release of NO from the endothelium and causes subsequent activation of soluble guanylyl cyclase in an active androgen receptor independent manner. This response may contribute to the observed antihypertensive actions of flutamide.     

Functional characterization of the human atrial essential myosin light chain (hALC-1) in a transgenic rat model

Most patients with hypertrophic cardiomyopathy and congenital heart diseases express the atrial essential myosin light chains (ALC-1) in their ventricles, partially replacing the ventricular essential light chains (VLC-1). This VLC-1/ALC-1 isoform shift is correlated with an increase in cross-bridge cycling kinetics as measured using skinned fibers from the hypertrophied ventricles of human hearts.To study the functional importance of hALC-1 in the intact perfused heart, we generated a transgenic rat model (TGR) overexpressing hALC-1 in the heart. Twelve-week-old TGR rats expressed 17±4 g hALC-1 per mg of whole SDS-soluble protein. Their perfused heart contractility parameters were evaluated using the Langendorff preparation. Expression of hALC-1 was accompanied by statistically significant improvements (P<0.001) in the contractile parameters of the hearts of the TGR compared to the age matched control (WKY) animals, represented by increases from 20.8±2.3 to 45.1±3.6 mmHg/g heart weight in the developed left ventricular pressure, 1,035.7±89.8 to 2,181±135.4 mmHg/s in the contraction rate, and 713±60.2 to 1,364±137.4 mmHg/s in the relaxation rate in the WKY and the TGR groups respectively. Characterizing the functional effects of hALC-1 at the whole organ level represents a step towards gene therapy of heart failure.     

What does TnCDANZ fluorescence reveal about the thin filament state?

Fluorescence of skinned psoas fibres reconstituted with the troponin C subunit labelled with the fluorescent probe dansylaziridine (TnC_DANZ) increases upon activation with Ca²⁺. This fluorescence enhancement is due to Ca²⁺ binding to the Ca²⁺-specific binding sites of TnC_DANZ and attachment of cross-bridges to the actin filament. We found that approximately 20% of the enhanced fluorescence signal derived from Ca²⁺ binding to TnC_DANZ and 80% from cross-bridge attachment during maximal activation. Furthermore we studied the effects of different cross-bridge states on TnC_DANZ fluorescence. Weakly bound, non-force-generating cross-bridge states (pCa 8, low ionic strength) and rigor cross-bridges revealed similar effects on the TnC_DANZ fluorescence. Strongly attached, force-generating states, however, increased fluorescence to the greatest extent. These results suggests a complex system of reciprocal couplings between TnC and different attached cross-bridge states. Cooling or increase of inorganic phosphate decreased isometric force but hardly decreased fluorescence, suggesting the accumulation of attached cross-bridge states with low tension output.     

Impact of a community pharmacy transitions-of-care program on 30-day readmission

Objectives

The primary objective of this study was to evaluate the impact of a transitions-of-care (TOC) program on both all-cause and related 30-day hospital readmission. The secondary objective was to evaluate which patient-specific factors, if any, are predictive of 30-day hospital readmissions.

Phosphorylation and thiophosphorylation by myosin light chain kinase: different effects on mechanical properties of chemically skinned ventricular fibers from the pig

The influence of myosin light chain phosphorylation (treatment with myosin light chain kinase = MLCK, calmodulin and ATP) and thiophosphorylation (incubation with MLCK, calmodulin and ATP gamma S) on the maximal shortening velocity (Vmax) and Ca2+ sensitivity of chemically-skinned ventricular fibers from the pig has been studied. Vmax was determined by the slack-test method and by extrapolation of the force-velocity relation by the isotonic quick release method. Vmax was 1.53 muscle length/s (L/s) and 1.94 L/s using the force-velocity relation and the slack-test, respectively. Phosphorylation increased the Ca2+ sensitivity for isometric force development of skinned fibers but had no influence on Vmax. Thiophosphorylation decreased Vmax but had no influence on Ca2+ sensitivity. Phosphorylation pattern of the myosin light chains of the skinned fibers was studied using [gamma-32P]ATP or [gamma-P35S]ATP (250 muCi each) and autoradiography. Incubation of skinned fibers with labeled ATP led to a phosphate incorporation into the 18-kDa myosin light chain (MPLC or regulatory light chain) while incubation with labeled ATP gamma S led to an incorporation of thiophosphate into the 28-kDa myosin light chain (alkali light chain) and tropomyosin. We suggest that the difference in mechanical behavior between phosphorylated and thiophosphorylated skinned fibers are due to differences in the phosphorylation profiles of myofibrillar regulatory proteins.     

Comparison of High Ribavirin Induction Versus Standard Ribavirin Dosing, Plus Peginterferon-α for the Treatment of Chronic Hepatitis C in HIV-Infected Patients: The PERICO Trial

Background.?Ribavirin (RBV) exposure seems to be critical to maximize treatment response in human immunodeficiency virus (HIV)-positive patients with chronic hepatitis C virus (HCV) infection. Methods.?HIV/HCV-coinfected individuals naive to interferon were prospectively randomized to receive peginterferon-α-2a (180?μg/d) plus either RBV standard dosing (1000 or 1200?mg/d if <75 or ≥75?kg, respectively) or RBV induction (2000?mg/d) along with subcutaneous erythropoietin β (450?IU/kg/wk), both during the first 4 weeks, followed by standard RBV dosing until completion of therapy. Early stopping rules at weeks 12 and 24 were applied in patients with suboptimal virological response. Results.?A total of 357 patients received ≥1 dose of the study medication. No differences in main baseline characteristics were found when comparing treatment arms. Sustained virological response (SVR) was attained by 160 (45%) patients, with no significant differences between RBV induction and standard treatment arms (SVR in 72 of 169 patients [43%] vs 88 of 188 [47%], respectively). At week 4, undetectable HCV RNA (29% vs 25%) and mean RBV trough concentration (2.48 vs 2.14?μg/mL) were comparable in both arms, whereas mean hemoglobin decay was less pronounced in the RBV induction plus erythropoietin arm than in the RBV standard dosing arm (-1.7 vs -2.3?mg/dL; P?相似文献   

TGF alpha has low protein expression in nonsyndromic clefts

Genetic studies have demonstrated that nonsyndromic cleft is composed of two separate entities: the cleft palate only and cleft of the lip, alveolus with or without cleft palate; both have a heterogeneous genetic background and environmental factors contribute to the onset of these malformations. The role of transforming growth factor alpha (TGF-A) was considered possible, but conflicting results have been reported. To detect if TGF-A is involved in the onset of cleft diseases, a series of patients with nonsyndromic clefts and control subjects were analyzed with regard to protein expression. Forty-three patients with nonsyndromic clefts and 21 unaffected subjects were enrolled in this study. Paraffin-embedded specimens were matched with TGF-A antibody and then scanned with a computerized image analyzer. TGF-A was scored as absent, moderately (from 10% to 30%), and highly expressed in epithelium, gland, and muscle. Data were statistically analyzed with a Kruskal-Wallis test. Comparison between control subjects and patients with clefts showed that only gland and epithelium reached a significant P value. A subsequent comparison between cleft of the lip, alveolus with or without cleft palate and cleft palate only groups demonstrated a statistically significant difference only for gland. TGF-A was decreasingly expressed in unaffected, cleft of the lip, alveolus with or without cleft palate, and patient with cleft palate only and thus further strength has been given to its role in the onset of the disease.