Oxidative stress and kidney dysfunction due to ischemia/reperfusion in rat: attenuation by dehydroepiandrosterone

BACKGROUND: The pathogenesis of ischemia/reperfusion (I/R) involves generation of reactive oxygen and nitrogen species. This in vivo study investigates the effect of dehydroepiandrosterone (DHEA), a physiologic steroid with antioxidant properties, on oxidative balance and renal dysfunctions induced by monolateral I/R. METHODS: Normal and DHEA-treated rats (4 mg/day x 21 days, orally) were subjected to monolateral renal I/R (30 minutes/6 hours). The oxidative state was determined by measuring hydrogen peroxide level and activities of glutathione-peroxidase, catalase, and superoxide dismutase. Tumor necrosis factor-alpha (TNF-alpha) and nitric oxide production and inducible nitric oxide synthase (iNOS) levels were also measured. Hydroxynonenal content was used to probe lipid peroxidation. Functional parameters determined were creatinine levels and Na/K-ATPase activity. Immunohistochemical and morphologic studies were also performed. RESULTS: A markedly pro-oxidant state was evident in the kidney of rats subjected to I/R. Both hydrogen peroxide and reactive nitrogen species (nitric oxide and iNOS) increased, whereas antioxidants decreased. Oxidant species induce TNF-alpha increase, which, in turn, produces lipoperoxidative processes, as documented by the increased hydroxynonenal (HNE) level. As final result, impaired renal functionality, hydropic degeneration, and vacuolization of proximal convolute tubules were observed in kidneys of I/R rats. DHEA pretreatment improved the parameters considered. CONCLUSION: I/R induces oxidative stress and consequently damages the proximal convolute renal tubules. Rats supplemented with DHEA and subjected to I/R had reduced pro-oxidant state, oxidative damage, and improved renal functionality, indicating an attenuation of oxidative injury and dysfunctions mediated by I/R.     

Four-Year persistence patterns among patients initiating therapy with the angiotensin II receptor antagonist losartan versus other artihypertensive drug classes

BACKGROUND: It has been reported that a statistically greater percentage of patients initially treated with losartan, an angiotensin II receptor antagonist (AIIA), stayed on therapy at 1 year compared with patients treated with antihypertensive drugs from other classes. OBJECTIVE: The purpose of this study was to determine whether the stay-on-therapy (persistence) patterns observed in the previous analysis were maintained over a 4-year period. METHODS: We investigated a subgroup of 15,175 hypertensive patients from an earlier studied cohort who were continuously eligible for benefits over a 4-year follow-up period. A linear regression model was developed to test the statistical significance of differences in the percentage of patients staying on therapy from 12 months to 48 months for the different antihypertensive classes. RESULTS: From 12 to 48 months, there was a slow continuous decline in persistence that was similar across all classes of antihypertensive medications. A greater percentage of patients treated with an AIIA (losartan) stayed on therapy from 12 to 48 months compared with patients treated with angiotensin-converting enzyme inhibitors (67.4% vs 60.7% at 12 months, P < 0.01; 50.9% vs 46.5% at 48 months, P = 0.095), calcium antagonists (67.4% vs 54.1% at 12 months, P < 0.01; 50.9% vs 40.7% at 48 months, P < 0.03), beta-blockers (67.4% vs 45.6% at 12 months, P < 0.01; 50.9% vs 34.7% at 48 months, P < 0.03), or thiazide diuretics (67.4% vs 20.8% at 12 months, P < 0.01; 50.9% vs 16.4% at 48 months, P < 0.03). The percentage of patients staying on AIIA therapy from 12 months to 48 months was statistically greater (P < 0.001) than the percentage of patients staying on therapy with other antihypertensive drug classes. CONCLUSIONS: This analysis supports the observation that initiation of antihylertensive therapy with an AIIA such as losartan results in a greater persistence rate over a 4-year period than does therapy with any other antihypertensive class. These findings may have important implications for blood pressure control, reduction of cardiovascular risks, and health care resource utilization.     

葛根素对高血压患者血浆内皮素和一氧化氮的影响

目的：检测正常人与高血压病（ＥＨ）患者血浆内皮素、一气体氮的变化及葛根素对其的干预效应。方法：ＥＨ对照组口服苯磺酸氨氯地平５ｍｇ／ｄ,或合和盐酸苯那普利１０ｍｇ／ｄ,每日一次,１５ｄ为一疗程。ＥＨ伍用治疗组同时合用５％ＧＮＳ２５０ｍｌ＋葛根素注射液４００ｍｇ静滴,两组治疗前后检测血浆ＥＴ、ＮＯ水平变化。结果：ＥＨ各组血浆ＥＴ较正常人组均显著增高（Ｐ〈０．０１）,血浆ＮＯ水平及ＮＯ／ＥＴ比值除轻度Ｅ     

Household income losses associated with ischaemic heart disease for US employees

OBJECTIVE: To estimate the cost of lost work days due to ischaemic heart disease (IHD), and the cost of this reduced productivity using reduction in household income. DESIGN AND SETTING: Using 2 years of nationally representative observational data, this study examined the effect on household income of IHD. This effect was estimated after accounting for unemployment, days lost to illness and other effects of illness on the income of workers aged 18 to 64 years. MAIN OUTCOME MEASURES AND RESULTS: Previous measures of indirect costs of disease have typically not included the loss in productivity due to suboptimal work performance. Among workers in this age group, IHD was associated with a reduction of $US3013 in annual household income; this reduction was independent of occupational class, age, size of household and educational level. Such a reduction may be because of reduced on-the-job performance, employer perception of this, or unrelated lifestyle choices. It represents an estimated $US6.05 billion annual loss in productivity in 1992 dollars (or $US6.45 billion in 1996 dollars). CONCLUSIONS: Estimates of the indirect costs of chronic disease that do not account fully for the lost income of employees may significantly underestimate the benefits to employers and society of treatment and prevention.     

Excretory urography with iohexol: evaluation in children

A multicenter clinical study was conducted using iohexol, a second-generation nonionic contrast medium, for excretory urography performed in 130 children. Doses of iohexol (300 mg iodine/ml) ranged between 150 and 660 mgI/kg (0.5 and 2.2 ml/kg). Iohexol was tolerated well, and no significant adverse reactions occurred. Sixty-five iohexol urograms were evaluated to determine the minimum dose for adequate visualization of the kidneys and collecting systems. A dose greater than 300 mgI/kg (1.0 ml/kg) always resulted in a urogram of diagnostic quality, while visualization was insufficient for diagnosis in 10% of studies done with doses of 150-300 mgI/kg (0.5-1.0 ml/kg). Another 65 iohexol urograms were compared in a blinded manner with a similar number of studies performed using iothalamate meglumine at comparable iodine concentration and dose. Visualization of calyces and pelvoinfundibular structures achieved with iohexol was rated better with statistical significance, but there was no difference in visualization of the renal parenchyma or ureters. Use of iohexol in excretory urography may be advantageous in children who are at greatest risk for an adverse reaction to contrast media or in those most likely to benefit from use of a low osmolality contrast agent.     

Scales for the measurement of attitudes toward blood donation

Attitudes toward blood donation are frequently assumed to vary along a single dimension from unfavorable to favorable. In contrast, theories of attitude structure specify three distinct attitude components: affect, cognition, and behavior. This article describes the development of three new scales for the measurement of affective, cognitive, and behavioral components of attitudes toward blood donation. The scales were developed using the method of equal-appearing intervals and were administered to both donors of blood and nondonors. Correlations among the scales were relatively small and supported the three-component distinction. Affect was more strongly correlated with the number of prior donations than was cognition, which suggested an important role for emotional factors in blood donation. Scores on all three scales showed the attitudes of blood donors to be more favorable than those of nondonors.