Search PubMed⌕ Search

Biomedical subjects

D E Ryan

Publications and source records attributed to D E Ryan.

130 records · Page 8Linked to original sources
PubMedDate not supplied

Blood lead levels in Sri Lankan families recovering gold and silver from jewellers' waste.

Blood lead levels were determined in controls and Sri Lankan families engaged in recovery of gold and silver from jewellers' waste using a molten lead procedure. Individuals with lead levels exceeding 40 micrograms/dL were found in families engaged in gold and silver recovery. The mean lead levels of such families (33 micrograms/dL) were always at least twice as high as those of their neighbors who were used as controls (12 micrograms/dL). High lead levels in these families were not restricted to individuals directly engaged in recovery work. In some cases, young children had up to 56 micrograms/dL of lead in their blood. It is concluded that gold and silver recovery represents a significant occupational health hazard in Third-World countries where the work is essentially a cottage industry. Such operations should be monitored by the appropriate health authorities and the individuals concerned should be informed of the potential health hazards.

Child↗
PubMedDate not supplied

Effects of three recombinant human leukocyte interferons on drug metabolism in mice.

Three recombinant human leukocyte interferons (IFLrA, IFLrD, and a hybrid IFLrA/D) that differ markedly in their antiviral activity in murine L cells were examined for their effects on hepatic microsomal drug metabolism in adult female CD-1 mice. When administered for 1 or 3 consecutive days, IFLrA/D, which exhibited the highest antiviral activity in murine L cells, caused a dose-dependent decrease in cytochrome P-450 content and in the rate of metabolism in vitro of benzo[a]pyrene, hexobarbital, 7-ethoxycoumarin, benzphetamine, and zoxazolamine. The concentration of cytochrome b and the activity of NADPH-cytochrome c reductase were also depressed when IFLrA/D was administered for 3 days. Similar but somewhat smaller changes were observed following treatment of mice with IFLrD, which possessed approximately 1% of the antiviral activity of IFLrA/D in murine L cells. In contrast, IFLrA, which was essentially devoid of antiviral activity in the mouse cell line, failed to depress cytochrome P-450 levels and in vitro drug metabolism activity in a consistent or dose-dependent manner. Cytochrome P-450 content and the in vitro rate of metabolism of benzphetamine and zoxazolamine were maximally depressed 8-24 hr after a single intraperitoneal injection of 1.5 micrograms of interferon per mouse; at this time the interferons were no longer detectable in serum. Near-normal levels of cytochrome P-450 and in vitro drug metabolism activity were restored by 48 hr after a single injection of interferon. Treatment of mice with 1.5 micrograms of IFLrA/D once daily for 3 days prolonged hexobarbital sleeping time but not zoxazolamine paralysis time, whereas neither of these was influenced by treatment with IFLrA or D. The results indicate that an interferon-dependent process reduces the level of microsomal cytochrome P-450 in liver and potentiates the pharmacological actions of certain drugs in mice.

Animals↗