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Biomedical subjects

R W Handy

Publications and source records attributed to R W Handy.

10 recordsLinked to original sources
PubMed2001

Isolation of symlandine from the roots of common comfrey (Symphytum officinale) using countercurrent chromatography.

Three pyrrolizidine alkaloids, symlandine, symphytine, and echimidine (1-3), were isolated from the roots of Symphytum officinale using a one-step countercurrent chromatography procedure. The structures of 1-3 were confirmed by several spectroscopic techniques including 2D NMR methods. This is the first description of the separation of symlandine (1) from its stereoisomer, symphytine (2).

Countercurrent Distribution↗
PubMedDate not supplied

Heavy metal exposure in populations living around zinc and copper smelters.

Arsenic, cadmium, and lead levels were determined simultaneously in multiple environmental media and human tissues in two zinc smelter (Bartlesville, Oklahoma and Palmerton, Pennsylvania) and two copper smelter (Ajo, Arizona and Anaconda, Montana) communities. Environmental media sampled included air, soil, household dust, and tap water; human samples included hair, blood, and urine. Between 200 and 300 residents from various age groups (1-5, 6-18, 20-40, and 60 + yr) were sampled in 1978 and 1979 and completed questionnaires in each of the four communities. Samples for all media were selected under a probability sampling framework at various distances from the smelters. Results of this investigation indicated that increased environmental levels and body burdens were exhibited at distances closest to the smelters. Of the three tissues sampled, hair was the most useful in determining relationships between environmental metal levels, distance, and body burden. Furthermore, while there was evidence that all ages had hair metal levels that were related to environmental levels and distance from the smelter, these relationships were much more pronounced for the 1- to 5-yr-old age group. The 1 to 5 yr olds also had the highest tissue metal levels across age groups. Higher hair metal levels were also found for males; smokers; children who ate paint, dirt, or clay; and for individuals who spent more time out of doors.

Adolescent↗
PubMedDate not supplied

The metabolism and toxicity of halogenated carbanilides. Biliary metabolites of 3,4,4'-trichlorocarbanilide and 3-trifluoromethyl-4,4'-dichlorocarbanilide in the rat.

In separate experiments, after repeated oral administration of 3,4,4'-trichlorocarbanilide (TCC) and 3-trifluoromethyl-4,4'-dichlorocarbanilide (TFC) to rats, the biliary metabolites of each were isolated and identified. The major TCC biliary metabolite was found to be 2'-hydroxy-TCC. This compound was isolated mainly from the nonconjugated and the glucuronide fractions. Other metabolites present in substantial quantities were 6-hydroxy-TCC and 2',6-dihydroxy-TCC mainly as glucuronides and 3'-hydroxy TCC mainly as the sulfate conjugate. Small amounts of 3',6-dihydroxy-TCC were isolated from each of the fractions. No unchanged TCC was found in the bile. Only traces of other metabolites were found, and no N-hydroxylated products were observed. The major TFC biliary metabolite was the glucuronide conjugate of 2'-hydroxy-TFC. The only other metabolite of TFC was 3'-hydroxy-TFC, which was the predominant metabolite in the sulfate-conjugated fraction.

Animals↗
PubMedDate not supplied

Biotransformation products of 3,4,4'-trichlorocarbanilide in rat, monkey, and man.

3,4,4'-Trichlorocarbanilide (TCC), uniformly labeled with 14C in the monochloro ring, was administered to rats, rhesus monkeys, and humans. Radioactive materials in the plasma and urine of all three species and in the bile of rats and monkeys were separated by high performance liquid chromatography. The chromatography showed great similarity between the monkey and the human. Principal metabolites common to all species were the sulfate and glucuronide conjugates of 2'-, 3'-, and 6-hydroxy-TCC. The rat also produced the glucuronide and sulfate conjugates of 2',6-dihydroxy-TCC. The major urinary excretion products found in humans and monkeys were the N- and N'-TCC glucuronides.

Animals↗
PubMedDate not supplied

Testing duplicate diet sample collection methods for measuring personal dietary exposures to chemical contaminants.

Dietary ingestion may be a significant pathway of human exposure to many potentially toxic chemicals. The U.S. Environmental Protection Agency-National Human Exposure Laboratory has made the development of methods for measuring personal dietary exposures a high priority for its dietary exposure research program. Of particular interest was the testing of methods that could be applied in the general population as one component of multipathway exposure measurement studies. This paper describes a controlled pilot study that was conducted to evaluate procedures for collecting and processing duplicate diet samples. Nine adult and three child participants volunteered to provide dietary information for 28 days, and duplicate portions of all foods consumed daily for seven consecutive days. Sample collection procedures were evaluated for participant collection and segregation of solid and liquid foods, and for identification and separation of high-fat and low-fat foods. Methods for compositing and homogenizing mixed diet samples were tested. Food records and questionnaires were tested to document the collected food and to evaluate procedures for assessing dietary changes and collection bias. Participant time and monetary needs were evaluated along with the approach for training and providing support to study participants. Participants were able to collect 96% of the meals they consumed, even with 33% of the meals consumed away from home. Food consumed in social settings was the most difficult to collect, and participants were unable or unwilling to collect foods in some social settings. Noncollection of meals and food items increased after the third day of collection. Mixed diet samples were successfully homogenized, with 1%-11% mean relative standard deviations for moisture, fat, protein, and ash analysis in replicate sample aliquots. The laboratory-measured caloric content of collected foods was an average of 12% (range: -24% to 36%) lower than estimates of energy intake using a food diary and 16% lower than estimated energy expenditure values.

Adolescent↗