Plasma epinephrine levels in hypertension and across gender and ethnicity.

Epinephrine (E) infusions raise blood pressure and there is an excess incidence of hypertension among males and blacks. However, reports of E levels by ethnicity, gender, and blood pressure status are inconsistent. Insensitive assays, variability in plasma E levels within individuals, and the small size of most studies have contributed to these conflicting reports. We measured plasma E levels in a large diverse sample of subjects, using a highly sensitive assay. A total of 361 individuals participated in the study: 61% were men and 39% women, 74% were normotensive and 26% hypertensive, 59% were white and 41% were black. Except for difference in blood pressure and body mass index between the normotensives and hypertensives, subjects had similar baseline characteristics and took no antihypertensive medications for at least five days prior to sampling. All blood samples were collected after resting for a least 30 minutes following the insertion of an indwelling i.v. catheter. Catecholamine levels were determined using a radioenzymatic assay (assay sensitivities for E and norepinephrine were 6 pg/ml and 10 pg/ml, respectively). An ethnicity by gender interaction was found (F(1,315) = 5.126, p = .024). Subsequent analysis revealed that white women had significantly lower basal plasma E levels than white men (p <0.001) and black women (p = 0.036). There were no significant differences in E levels between black men and women or between white men and black men. Uncorrected E levels were lower in normotensive than hypertensive subjects (p = .009) but this difference was not significant when corrected for body mass index (BMI). Uncorrected norepinephrine levels were higher in women than men (p = .03) but the difference was no longer significant when corrected for BMI. Plasma E levels were significantly lower among white women than men or black women. In contrast to prior studies, E levels were lower in hypertensives, but this may reflect obesity among hypertensives.

Prevalence of hepatitis C virus infection at three hemodialysis units in the western region of Puerto Rico.

OBJECTIVE: In the United States hepatitis C virus infection (HCV) affects approximately 20 percent of hemodialysis patients but its prevalence in Puerto Rico has not been established. We have sought to determine the prevalence of HCV infection in a homogeneous sample of patients on hemodialysis in the western region of Puerto Rico and to identify its risks factors. METHODS: All patients in the hemodialysis units of Aguadilla, Mayagüez and San Germán, during December 1997 to March 1998, completed a written questionnaire in which they were asked about transfusions, multiple sexual partners, i.v. drugs use, tattooing, occupation, imprisonment, organ transplantation and years on hemodialysis. Serum samples were analysed for HCV antibodies by an enzyme-linked immunoadsorbent assay (ELISA). Sera with positive results for HCV were subjected to a confirmatory test by the polymerase chain reaction (PCR). RESULTS: Thirteen of the 376 (3%) subjects had a positive ELISA (one patient died prior the confirmatory test with PCR). Six out of the twelve patients had a positive PCR. Two had been transfused. Three were illicit i.v. drug users and one had received a renal transplant. The liver biopsies in all patients showed chronic hepatitis and in two there was cirrhosis. CONCLUSIONS: Our prevalence was two percent. As reported elsewhere blood transfusion, organ transplantation and illicit i.v. drug abuse were the major risk factors for HCV infection in our patients. Nosocomial factors were irrelevant in the results.