Biomedical subjects

B Houston

Publications and source records attributed to B Houston.

39 records · Page 3Linked to original sources

PubMedDate not supplied

A kinetic analysis of the 5 alpha-reductases from human prostate and liver.

A kinetic analysis of the 5 alpha-reductases from human liver and prostate is presented. Human prostatic 5 alpha-reductase follows an ordered sequential mechanism in which NADPH binds first followed by testosterone. The order of release of products is DHT followed by NADP+. The apparent Km of prostatic 5 alpha-reductase for testosterone is 0.0339 +/- 0.006 microM, while the apparent Km for NADPH is 2.52 +/- 0.65 microM. Human liver 5 alpha-reductase also follows a sequential mechanism. The apparent Km of the liver enzyme is 0.110 +/- 0.08 microM; the apparent Km for NADPH is 6.2 +/- 0.6 microM. The fact that both the liver and prostatic 5 alpha-reductases have a sequential kinetic mechanism rules out the possibility that the reduction of testosterone to dihydrotestosterone involves an electron transport system as previously proposed.

Cholestenone 5 alpha-Reductase↗

PubMedDate not supplied

No significant effects of sodium aurothiomalate on haem metabolism and mixed function oxygenase activity in patients with rheumatoid arthritis.

OBJECTIVE: Animal studies suggest that gold compounds impair haem synthesis and increase haem degradation and, as a result, reduce activity of the hepatic haemoproteins cytochromes P-450. The aim of this study was to investigate whether intramuscular gold exerts similar effects in patients with rheumatoid arthritis (RA). METHODS: Urinary porphyrin and precursor excretion, erythrocyte protoporphyrin, and antipyrine clearance, were measured in 6 patients with RA before and 10 weeks after commencement of intramuscular gold. RESULTS: Parameters of haem metabolism were unaffected by gold. While antipyrine clearance was not statistically changed after gold treatment, in 3 of the patients there was an average decrease in antipyrine clearance of 23%. CONCLUSION: Further studies examining RA patients at different time points are required to investigate further the possibility of reduced hepatic drug metabolising activity during prolonged treatment with gold.

Adult↗

PubMedDate not supplied

Lead testing of children and homes: results of a national telephone survey.

OBJECTIVES: This study was designed to estimate the percentage of young children in the United States who have been tested for lead and the percentage of dwellings in the United States in which the paint has been tested for lead. METHODS: A national random digit dial telephone survey of 5238 households was conducted in 1994. Weighted national estimates and 95% confidence intervals for outcomes of interest were calculated. RESULTS: About 24% of U.S. children ages 0 to 6 years were estimated to have been tested for lead. Higher rates of testing were reported for children living in homes constructed prior to 1960, those living in homes with low household income, those living in rental units, and those living in the Northeast. Lead paint testing was performed for only an estimated 9% of U.S. housing units. Older homes were not more likely to have been tested than newer ones. CONCLUSION: A high proportion of pre-school children have apparently not been screened for lead exposure, even among subgroups at increased risk. Most dwellings of pre-school children have not been tested for lead paint. These data suggest that most at-risk children are not being reached by current approaches to lead poisoning prevention.

Child↗