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Biomedical subjects

R Washington

Publications and source records attributed to R Washington.

23 records · Page 2Linked to original sources
PubMed1975

Urinary iron in patients with sickle cell anamia.

Urinary iron excretion was measured in patients with sickle cell anemia and relateddiseases. Iron concentration in urine was determined by atomic absorption spectrophotometry and daily total iron excretion was calculated from this and total daily urine volume. Normal subjects excreted a mean of 88 pg Fe per day (95 per cent confidence limitsof 0 to 120 pg). Nine persons with sickle cell trait had normal Fe excretion rates.However, abnormally high iron excretion was present in the first urine sample obtainedfrom 27/31 patients with SS, 3/7 with SC, 1/2 with CC, and 1 with S-thalassemia. Iron excretion varied very significantly from day-to-day in individual patients. The results of studies attemting to relate this to increase excretion during activityas compared to rest were negative. No clear relationship of iron excretion to painfulcrisis could be shown, but remarkable rises in urine iron occurred in two patients who developed a hyperhemolytic crisis. These studies suggest that urinary iron reflects intravascular hemolysis primarily. No correlation was evident between urine iron and the patients' age, transfusion history, or serum iron values suggesting increased urinary iron excretion cannot be attributed to iron overload in sickle cell anemia.

Adolescent↗
PubMedDate not supplied

Pulmonary vascular extraction of circulating norepinephrine in infants with bronchopulmonary dysplasia.

Although the pulmonary circulation in infants with advanced bronchopulmonary dysplasia (BPD) is characterized by abnormal structure and vasoreactivity, metabolic lung functions have not been studied in these infants. To test the hypothesis that patients with severe BPD may have abnormal metabolic lung function, we assessed the pulmonary vascular extraction of circulating norepinephrine in six children with BPD during cardiac catheterization. Plasma norepinephrine levels were measured from simultaneously drawn mixed venous (main pulmonary artery) and left atrium or femoral artery samples. In comparison with four infants with mild heart disease without pulmonary hypertension, we found that infants with BPD extract proportionately less norepinephrine than non-BPD infants [-7 +/- 50% (BPD) versus +27 +/- 6% (non-BPD); P less than 0.001, t test]. Three infants with BPD had higher arterial than mixed venous concentrations of plasma norepinephrine, suggesting net production across the lung. Plasma catecholamine levels and percent extraction correlated poorly with cardiac index and systemic and pulmonary vascular resistance indices. However, this study group was characterized by a high incidence of pulmonary (6/6) and systemic (4/6) hypertension, left ventricular hypertrophy (4/6), and subsequent death (3/6). We conclude that infants with severe BPD and pulmonary hypertension have decreased pulmonary vascular clearance or net production of circulating norepinephrine, but links between altered pulmonary catecholamine metabolism and pulmonary hypertension, or other cardiovascular abnormalities associated with BPD, remain speculative.

Bronchopulmonary Dysplasia↗
PubMedDate not supplied

The Africentric Transtheoretical model in a school-based pregnancy prevention program.

This article describes the use of a socio-culturally specific framework for a pregnancy prevention program for low income 10 to 12 year old African American middle school girls. The framework expands earlier (Johnson, 1995) conceptualizations by combining African and African American frames of reference with behavior change processes to influence sexual decision-making among young adolescents.

Adolescent↗