Search PubMed⌕ Search

Biomedical subjects

R S Cooper

Publications and source records attributed to R S Cooper.

179 records · Page 10Linked to original sources
PubMedDate not supplied

Effectiveness of prostaglandin E1 in relieving obstruction in coarctation of the aorta without opening the ductus arteriosus.

The two main theories regarding the pathogenesis of coarctation of the aorta are the Skodaic hypothesis of ductal tissue constricting the aorta at the level of the insertion of the ductus arteriosus and the flow theory of decreased ascending aortic blood flow in the fetus, which results in associated isthmic narrowing and a localized shelf. To document that ectopic ductal tissue constriction can cause coarctation of the aorta in the absence of a patent ductus arteriosus, we report three cases of infants presenting with critical coarctation who responded to prostaglandin E1 infusion without opening the ductus arteriosus.

Alprostadil↗
PubMedDate not supplied

Fluorescence line narrowing-nonphotochemical hole burning spectrometry: femtomole detection and high selectivity for intact DNA-PAH adducts.

A new fluorescence line narrowing (FLN) apparatus is described and evaluated through experiments on intact DNA-PAH (polycyclic aromatic hydrocarbon) and globin-PAH adducts, as well as polar PAH metabolites. A detection limit of approximately 3 modified bases in 10(8) for a DNA adduct formed with a diol-epoxide of benzo[a]pyrene (BPDE-DNA) is reported for 20 micrograms of DNA at a spectral resolution of approximately 8 cm-1. The methodology employed avoids or minimizes spectral degradation and loss of sensitivity due to photooxidation and nonphotochemical hole burning (NPHB). A new double selection technique that employs both FLN and NPHB is described and found to lead to a significant improvement in selectivity over that obtained with conventional FLN.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗
PubMedDate not supplied

Fluorescence line narrowing spectrometric analysis of benzo[a]pyrene-DNA adducts formed by one-electron oxidation.

Fluorescence line narrowing (FLN) was demonstrated for five benzo[a]pyrene (BP)-nucleoside adducts synthesized by one-electron oxidation of BP in the presence of guanosine, deoxyguanosine, and deoxyadenosine. The standard FLN spectra were used to prove that a major depurination adduct from the binding of BP to DNA in rat liver nuclei is 7-(benzo[a]pyren-6-yl)guanine (N7Gua). The structural characterization was performed with only 20 pg of the adduct. Metabolic activation of BP by one-electron oxidation in the horseradish peroxidase catalyzed reaction of BP with DNA (in vitro) was also investigated. The major adduct identified was 8-(benzo[a]pyren-6-yl)guanine (C8Gua).

Animals↗
PubMedDate not supplied

Relationship between premature mortality and socioeconomic factors in black and white populations of US metropolitan areas.

OBJECTIVE: examined the association of mortality with selected socioeconomic indicators of inequality and segregation among blacks and whites younger than age 65 in 267 US metropolitan areas. The primary aim of the analysis was to operationalize the concept of institutional racism in public health. METHODS: Socioeconomic indicators were drawn from Census and vital statistics data for 1989-1991 and included median household income; two measures of income inequality; percentage of the population that was black; and a measure of residential segregation. RESULTS: Age-adjusted premature mortality was 81% higher in blacks than in whites, and median household income was 40% lower. Income inequality, as measured by the Gini coefficient, was greater within the black population (0.45) than within the white population (0.40; p < 0.001). To confirm that the proxy socioeconomic variables were relevant markers of population health status, regression analysis was performed initially on data for the total population. These variables were all independently and significantly related to premature mortality (p < or = 0.01; R(2) = 0.74). Income inequality for the total population was significantly correlated with premature mortality (r = 0.33). Black (r = 0.26) and white (r = 0.20) population-specific correlations between income inequality and premature mortality, while still significant, were smaller. Residential segregation was significantly related to premature mortality and income inequality for blacks (r = 0.38 for both); among whites, however, segregation was modestly correlated with premature mortality (r = 0.19) and uncorrelated with income inequality. Regional analyses demonstrated that the association of segregation with premature mortality was much more pronounced in the South and in areas with larger black populations. CONCLUSION: Social factors such as income inequality and segregation strongly influence premature mortality in the US. Ecologic studies of the relationships among social factors and population health can measure attributes of the social context that may be relevant for population health, providing the basis for imputing macro-level relationships.

Adolescent↗
PubMedDate not supplied

Cardiac MR imaging in Pompe disease.

The magnetic resonance (MR) imaging findings in a 5-month-old infant with glycogen storage disease of the heart revealed hypertrophy of the right and left ventricles and the interventricular septum with an irregular inhomogeneous appearance of the myocardium. The descriptive features of the MR study are correlated with cardiac angiography and echocardiography in Pompe disease.

Angiocardiography↗
PubMedDate not supplied

Can overnight urine replace 24-hour urine collection to asses salt intake?

Are overnight urine specimens adequate for characterizing the daily salt intake of individuals, i.e., can the overnight specimen replace the 24-hour specimen? Data from 142 male participants of an ongoing trial on the primary prevention of hypertension were used to examine this question with correlation analysis and quantile classification. Estimated correlation between the true mean 24-hour and the true mean overnight sodium excretion was 0.72. Furthermore, 67% of the individuals in the upper third of the distribution of true mean overnight urine sodium were also in the upper third of the distribution of true mean 24-hour sodium. Thus, these data are promising in regard to the use of overnight urine specimens for characterizing the salt intake of individuals. The number of overnight urine collections required to estimate accurately the correlation between an individual's true mean overnight urine sodium and a variable of interest (e.g., blood pressure) was calculated. Given the observed intra- and inter-individual variation, the data indicate that 14 measurements are needed to limit the diminution of the correlation coefficient to 10%.

Adult↗
PubMedDate not supplied

Prevalence of diabetes and impaired glucose tolerance in Nigerians, Jamaicans and US blacks.

The prevalence of type 2 diabetes, impaired glucose tolerance and associated risk factors were compared in sample surveys in Africa and the Caribbean with the Third National Health and Nutrition Survey (NHANES-III) from the United States. A total of 856 Nigerians, 1286 Jamaicans, and 1827 US blacks were included in the study. Body mass index (BMI) increased in a stepwise fashion across the three populations groups, ie, 23 kg/m2 in Nigerians, 26 kg/m2 in Jamaicans, and 28 kg/m2 in US blacks. The corresponding age-adjusted prevalences of type 2 diabetes among persons aged 25-74, were 1%, 12%, 13%. Jamaican women were found to have the same prevalence of type 2 diabetes as US women (14 vs 13%, respectively); mean BMI was likewise very similar (28 kg/m2 in Jamaican and 29 kg/m2 in US women). BMI and waist-to-hip ratio were both associated with type 2 diabetes prevalence. Findings of this study confirm the marked gradient in type 2 diabetes risk among these genetically related populations and suggest that the blacks in the island nations of the Caribbean and the United States are at particularly high risk. Nigerians exhibited remarkably well-preserved glucose tolerance. Understanding the factors that limit the risk of type 2 diabetes in West Africa, beyond relative absence of obesity, would have considerable public health significance.

Adult↗
PubMedDate not supplied

The relation of central adiposity to components of the insulin resistance syndrome in a biracial US population sample.

The higher rates of type 2 diabetes mellitus, hypertension, and many others factors of the insulin resistant syndrome (IRS) often seen in African Americans compared to whites do not seem to be explained by differences in central obesity. Reasons for this may be due, in part, to the validity of the commonly used anthropometric surrogate of central adiposity. Recent findings have shown that waist circumference is a better surrogate of total body and visceral adipose tissue and is better correlated with CVD than the traditionally used anthropometric indexes of the body mass index or waist/hip ratios. In this study, waist circumference was employed to determine the association between central adiposity and components of the insulin resistance syndrome in blacks (N=1963) and whites (N=4894) from the US national population-based samples. Sex-specific correlation coefficients were used to estimate the association between waist circumference and factors of the IRS. Multiple linear regression analyses were used to determine racial differences in waist circumference and the independent association of waist circumference to some known factors of IRS adjusting for age, BMI, alcohol use, and smoking. Waist circumference was positively correlated with plasma glucose, DBP, SBP, LDL cholesterol, fasting insulin, serum triglyceride, total cholesterol and total cholesterol/HDL ratio in black and white men and women (P<0.01). In both biracial groups, waist circumference was significantly associated with increases in glucose, DBP, LDL cholesterol, total cholesterol, triglyceride and fasting insulin levels controlling for age, BMI, and behavioral risk factors, such as alcohol use and smoking (P<0.05). Our data shows that central adiposity assessed with waist girth did not wholly explain the higher prevalence of IRS components often seen among blacks. The results of this study reinforce the need to encourage the use of waist measure as a public health tool in screening for CVD risks.

Abdomen↗
PubMedDate not supplied

Oversizing of donor hearts: beneficial or detrimental?

To determine the effects of donor/recipient weight mismatch on allograft function and survival after orthotopic heart transplantation, we retrospectively compared the clinical and the hemodynamic characteristics of recipients weighing more than their donor ("undersized") with those of recipients weighing less than their donor ("oversized"). The median follow-up period was 24 months (range, 0 to 67 months). In 88 patients (59%) donor weight was 1% to 46% less than recipient weight (13.5 +/- 8.9 means +/- SD). In 61 patients (41%) donor weight exceeded recipient weight by 0% to 139% (20% +/- 23%). When recipient ideal body weight was used in the analysis, 75 patients (51%) were undersized by 1% to 59% (13% +/- 10%), and 72 patients (49%) were oversized by 0% to 67% (19% +/- 18%). Preoperative transpulmonary gradient, ventricular function, and exercise tolerance were similar in the two groups. The number and severity of episodes of rejection and infection after transplantation were also similar in the two groups 1, 6, and 12 months after transplantation. When recipient ideal weight was used in the analysis, right ventricular (RV) and left ventricular (LV) ejection fractions (EFs) were within normal limits (RVEF greater than 40%; LVEF greater than or equal to 45%) and similar in the two groups. When recipient actual weight was used in the analysis, the LVEF measured at 12 months after heart transplantation was higher in the oversized than in the undersized group (52 +/- 11 vs 46 +/- 10; p less than 0.05). Postoperative hemodynamic values and exercise tolerance were similar in the two groups regardless of whether recipient weight or ideal body weight were used in the analysis. Forty-six recipients died 0 to 46 months (median, 7 months) after orthotopic heart transplantation. In a Cox regression model, recipients with donor weight greater than recipient ideal weight had a significantly greater risk of death within the follow-up period than did recipients with donor weight less than recipient ideal weight (relative risk = 2.19; p less than 0.05). When percent donor weight/recipient ideal weight mismatch was used as a continuous variable, donor heart oversizing was negatively related to survival, independent of preoperative transpulmonary gradient values (p less than 0.05). In contrast to common belief, oversizing of donor hearts does not improve the outcome of orthotopic heart transplant recipients who have reversible preoperative pulmonary hypertension. Acceptance of undersized donor hearts is not detrimental to allograft function and recipient survival. Use of undersized donor hearts may maximize the use of critically scarce donor organs.

Adult↗
PubMedDate not supplied

Continued adverse trends in coronary heart disease mortality among blacks, 1980-91.

An abrupt downturn in mortality rates from coronary heart disease occurred in the United States in the mid-1960s, and for the next decade all four major sex-race groups experienced virtually identical rates of decline. Beginning around the mid-1970s, however, trends for blacks and whites began to diverge, with a deceleration in the annual fall in rates for blacks. The recent release of mortality data extending through 1991, with correction of the denominator estimates in the 1980s using the 1990 census, demonstrate a striking linearity of this trend over the entire decade. In 1989, for the first time since the category of coronary heart disease has been recorded in vital statistics, the age-adjusted death rate for it among black men exceeded that of whites. As a result of the divergent trends among men, an excess of 4,000 deaths of blacks were recorded in 1991 alone. Among women, coronary heart disease mortality was higher among blacks at the beginning of this period, and the average annual percent decline was only two-thirds that of whites. As a result, the absolute mortality gap between blacks and whites steadily increased from 19 to 33 percent (1980 to 1991). This study indicates that the factors that have led to the decline in coronary heart disease have not influenced all demographic groups equally over the last decade.

Adult↗
PubMedDate not supplied

The relative effects of left ventricular hypertrophy, coronary artery disease, and ventricular dysfunction on survival among black adults.

OBJECTIVE: To evaluate the effect of echocardiographically determined left ventricular hypertrophy (LVH) on survival in comparison with number of stenosed vessels and left ventricular systolic dysfunction. DESIGN: Cohort study based on a consecutive sample from a hospital registry, with a mean follow-up of 5 years. SETTING: An inner-city public hospital in Chicago, Ill. PATIENTS: The study included 1089 consecutive black patients who underwent both coronary angiography and M-mode echocardiography as part of a diagnostic evaluation. RESULTS: Nonstenosed coronary arteries, single-vessel disease, and multivessel disease were found in 48%, 16%, and 36% of patients, respectively; LVH (left ventricular mass index > 131 g/m2 in men and > 100 g/m2 in women) was detected in 50% of patients. Hypertrophy without coexistent obstructive coronary disease was associated with a lower survival rate than that observed for single-vessel disease and was similar to multivessel disease. When LVH, number of diseases vessels, and left ventricular dysfunction were subjected to multivariate analysis, hypertrophy conferred a relative risk (RR) of 2.4 (95% confidence interval [CI], 1.7 to 3.2). By comparison, the presence of a single stenosed vessel did not increase the risk of death. Multivessel disease and ejection fraction less than 45% were associated with an RR of 1.6 (95% CI, 1.1 to 2.2) and 2.0 (95% CI, 1.4 to 2.7), respectively. Calculation of the attributable risk fraction demonstrated that for every 100 deaths in this cohort, LVH independently accounted for 37. The corresponding attributable risk fractions were 1%, 22%, and 9% for single-vessel disease, multivessel disease, and ventricular dysfunction, respectively. CONCLUSIONS: Left ventricular hypertrophy was associated with a greater RR and attributable risk than the traditional measures of coronary disease severity. The high prevalence and powerful risk of LVH make an important contribution to the adverse survival rates among black patients with heart disease and may account for much of the black-white differential.

Aged↗
PubMedDate not supplied

A case study in the use of race and ethnicity in public health surveillance.

Increased attention has been focused on the use of racial and ethnic categories in public health research and surveillance in recent years. This attention, however, has done more to increase the collective awareness of the difficulties inherent in these classification schemes than to resolve either the theoretical or practical problems. It has been recognized for many years that health outcomes for a particular ethnic population must be seen as an interaction between genetically determined factors and socially mediated exposures. The operational meaning of these concepts remains poorly defined, however. Although the general biologic construct of race and ethnicity appears straightforward, appearance is deceiving and the technical requirements that allow formulation of a rigorous and objective working definition have never been fully developed. The social factors that influence ethnic health differentials are perhaps better understood in practical terms; measurement of many of the relevant variables remains difficult, however. In this article an attempt is made to outline the implications of the new developments in molecular biology for the concept of race, and to provide an illustrative example of the continued evolution of the social determinants of ethnicity.

Data Collection↗
PubMedDate not supplied

In search of the hypothesis.

Epidemiologic studies of racial differences sorely lack sound and explicit hypotheses. Race is a social convention, not a biological concept. Its careless use in epidemiology demonstrates a failure to generate appropriate hypotheses to study its role in health. Studies of hypertension in blacks illustrate the point. Two underlying pitfalls plague hypothesis generation: directionality involving the null and alternative hypotheses and circularity, where efforts to understand social factors have the effect of emphasizing racial differences. The proper prescription is to identify explicitly the hypotheses of interest, including their origins and implication.

Black People↗