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Biomedical subjects

C S Clark

Publications and source records attributed to C S Clark.

43 records · Page 3Linked to original sources
PubMed1980

Fecal lead excretion in young children as related to sources of lead in their environments.

Fecal lead excretion (PbF) was studied in young children with elevated lead exposure. PbB was generally 40-70 microgram/dl. The children's home environments were classified as to lead-base paint hazard and traffic density. There was a significant correlation between paint hazard classification and PbF but not between traffic density and PbF. There also was a correlation of PbB with paint hazard classification. Long-term fecal collections were instituted using 10 children who lived in high hazard homes and three children with low PbB's, whose PbF's were considered normal. Among the children living in high hazard homes, median fecal lead excretion generally was only moderately elevated. Grossly elevated amounts of led were found only occasionally and only in a few of the children. Movement of two children from a high hazard home to a low hazard home resulted in prompt and substantial reduction in PbF. By contrast, PbB fell only very slowly.

Child↗
PubMedDate not supplied

An environmental health survey of drinking water contamination by leachate from a pesticide waste dump in Hardeman County, Tennessee.

Ground water that was used as a source of potable water by residents of a small community became contaminated by leachate from a 300,000 barrel pesticide waste dump. An environmental health survey of the residents and an apparent control group was conducted to determine if any adverse health effects resulting from exposure to the toxic compounds, many of which were hepatotoxins, could be detected. The survey utilized a health questionnaire, a clinical examination, and a biochemical screening. The latter included analysis of serum for liver and kidney function parameters, determination of hepatitis A and B serology, and bile acid determinations on fasting and postprandial serum and urine specimens. Air and water from representative homes and urine from study participants were analyzed for selected organic compounds. The biochemical screening was conducted on two occasions 2 months apart. The initial hepatic profile testing revealed elevated concentrations of the serum enzymes, alkaline phosphatase and serum glutamic oxaloacetic transaminase, in residents who had used the contaminated water. During follow-up testing of these same persons 2 months later, these values were significantly reduced, as were postprandial serum concentrations of the bile acid of cholyglycine. Six individuals in the exposed group had slight hepatomegaly compared to one individual in the intermediate exposure group and none in the controls. Concentrations of carbon tetrachloride were as high as 18,700 microgram/L in the well water samples. The biochemical and clinical observations are suggestive of a transitory liver injury probably related to exposure to the contaminated drinking water.

Adolescent↗
PubMedDate not supplied

Gastroesophageal reflux induced by exercise in healthy volunteers.

The effects of different types of exercise on gastroesophageal reflux were evaluated during fasting and postprandially in 12 asymptomatic volunteers (7 men and 5 women; mean age, 28 years) using an ambulatory intraesophageal pH monitor. The 1-hour exercise period included stationary bicycling (aerobic exercise with little agitation of the body), running (aerobic exercise with a high degree of agitation of the body), and a weight routine (nonaerobic exercise). Each exercise was performed for 15 minutes with 5 minutes of rest between exercises. The weight routine consisted of five different exercises (sit-ups, bench press, sitting arm press, prone leg curls, and sitting leg press) chosen to compare upper-body vs lower-body exercise and supine vs upright position. Each exercise hour was preceded by a 1-hour baseline period on 2 days (fasting and postprandial). The results indicate that vigorous exercise can induce gastroesophageal reflux in normal subjects. Running induced the most reflux, and aerobic exercises with less bodily agitation (bicycle) produced less reflux and may offer an alternate form of exercise for patients with reflux. The weight routine induced gastroesophageal reflux in some subjects, although no particular exercise was associated with more reflux. Postprandial exercise showed a similar pattern of induced gastroesophageal reflux, although of greater amount.

Adult↗