Pulmonary vasorelaxant activity of atrial natriuretic peptide and brain natriuretic peptide in humans.

BACKGROUND--Atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) exhibit in vitro pulmonary vasodilator activity, but little information is available regarding their effects in the human pulmonary vasculature. Their effects in the human pulmonary circulation and their ability to modulate the pulmonary pressor effects of angiotensin II have therefore been evaluated. METHODS--Eight healthy volunteers were studied on three separate occasions. Infusions of either ANP, BNP, or placebo were given for 60 minutes with a concomitant infusion of angiotensin II given for the final 30 minutes. Pulmonary haemodynamics were measured by pulsed wave Doppler echocardiography at baseline (T0), before commencing angiotensin II (T30), and at the end of the infusion period (T60). RESULTS--Mean pulmonary artery pressure (MPAP) showed a fall with ANP and BNP infusion at T30 compared with placebo. Although angiotensin II infusion had significant pulmonary pressor effects on all three study days, MPAP at T60 was lower when ANP (18.3 (2.0) mm Hg) and BNP (16.1 (1.5) mm Hg) were given concomitantly compared with placebo (21.8 (1.6) mm Hg). CONCLUSIONS--These findings indicate that both ANP and BNP exhibit pulmonary vasorelaxant activity in humans in terms of antagonism of the pulmonary pressor effects of angiotensin II. This would support the hypothesis that ANP and BNP act as circulating counter-regulatory hormones in states of pathological pulmonary vasoconstriction.     

Inequalities in full immunization coverage: trends in low- and middle-income countries

ObjectiveTo investigate disparities in full immunization coverage across and within 86 low- and middle-income countries.MethodsIn May 2015, using data from the most recent Demographic and Health Surveys and Multiple Indicator Cluster Surveys, we investigated inequalities in full immunization coverage – i.e. one dose of bacille Calmette-Guérin vaccine, one dose of measles vaccine, three doses of vaccine against diphtheria, pertussis and tetanus and three doses of polio vaccine – in 86 low- or middle-income countries. We then investigated temporal trends in the level and inequality of such coverage in eight of the countries.FindingsIn each of the World Health Organization’s regions, it appeared that about 56–69% of eligible children in the low- and middle-income countries had received full immunization. However, within each region, the mean recorded level of such coverage varied greatly. In the African Region, for example, it varied from 11.4% in Chad to 90.3% in Rwanda. We detected pro-rich inequality in such coverage in 45 of the 83 countries for which the relevant data were available and pro-urban inequality in 35 of the 86 study countries. Among the countries in which we investigated coverage trends, Madagascar and Mozambique appeared to have made the greatest progress in improving levels of full immunization coverage over the last two decades, particularly among the poorest quintiles of their populations.ConclusionMost low- and middle-income countries are affected by pro-rich and pro-urban inequalities in full immunization coverage that are not apparent when only national mean values of such coverage are reported.     

Chronic hepatitis C in Latinos: natural history, treatment eligibility, acceptance, and outcomes

OBJECTIVES: The natural history of chronic hepatitis C and treatment response are different between blacks and Caucasians, but little comparable data is available about Latinos. METHODS: A cross-sectional secondary analysis to investigate differences between 421 anti-HCV-positive, treatment-na?ve, HCV-viremic Latinos and 2,510 Caucasians in 24 VA medical centers enrolled in a prospective study. RESULTS: Latinos were infected at a younger age and were less likely to have blood contact during combat, surgery, and needle stick injury, but were more frequently HIV coinfected (20.4%vs 3.9%, p < 0.0001) and prior HAV infection (39.9%vs 26.4%, p= 0.0001). Latinos were more likely to be treatment candidates, but less likely to actually initiate treatment. Liver histology (123 Latinos, 743 Caucasians) showed no difference in fibrosis or fibrosis rate, but steatosis (54.7%vs 43.2%, p= 0.038) was more common in Latinos. Eighty-eight Latinos and 481 Caucasians were subsequently treated with interferon-ribavirin: body mass index (BMI), duration of infection, baseline tests, liver histology and genotype distribution were similar. Compared with Caucasians, Latinos discontinued treatment prematurely more often (39.8%vs 28.9%, p= 0.043) and tended to have lower sustained virological response (SVR) rates (14.8%vs 22.5%, p= 0.10). Multivariate analysis found Latino race and history of recent alcohol use to be associated with early treatment discontinuation, whereas genotype and viral load but not ethnicity to be associated with SVR. CONCLUSIONS: Latinos were infected younger, more frequently HIV coinfected, more likely to meet criteria for antiviral therapy yet less likely to initiate treatment and had a trend toward lower SVR rates than Caucasians, but not in severity of liver disease. Latino ethnicity was associated with early discontinuation but not as an independent predictor of SVR.     

Does the presence of hibernating myocardium in patients with impaired left ventricular contraction affect QT dispersion?

BACKGROUND: Hibernating myocardium is associated with increased cardiovascular events. Increased QT dispersion on the surface electrocardiogram is a marker for serious ventricular arrhythmias. In this study, we determine whether hibernating myocardium is associated with increased QT dispersion in patients with coronary artery disease and impaired left ventricular contraction. METHODS: Positron emission tomography with (13)N-ammonia and (18)F-fluorodeoxyglucose determined the presence of metabolic-perfusion mismatch defect. QT dispersion was measured by means of a digitizing tablet with validated software. QT intervals were measured on two separate occasions by two investigators blinded to the result of the positron emission tomography scans. RESULTS: Forty-two patients with impaired left ventricular contraction were studied. They were divided into two groups: group A was made up of patients with mismatch defects (n = 26) and group B was made up of patients with no mismatch defects (n = 16). The mean (SD) QT dispersion measurements were 61.7 +/- 29.8 ms and 70 +/- 24.6 ms for groups A and B, respectively (not significant). When the patients were divided according to the dominant viability status of the impaired myocardial segment, a similar result was found. The patients whose impaired myocardium was dominantly hibernating (n = 19) had a mean QT dispersion of 66.4 +/- 31.9 ms compared with 63.6 +/- 24.8 ms in the patients whose impaired myocardium was mainly scarred (not significant). CONCLUSIONS: QT dispersion is not affected by the presence of hibernating myocardium and is therefore not clinically useful in identifying patients with this phenomenon. This is in contrast with recent reports by other groups and calls for further investigation of this dichotomy.