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Biomedical subjects

J Duffy

Publications and source records attributed to J Duffy.

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

Comparison of two dosage schedules of gold salts in the treatment of rheumatoid arthritis. Relationship of serum gold levels to therapeutic response.

Two doses of gold sodium thiomalate were compared for their effect on rheumatoid arthritis. Thirty-seven patients with active disease for longer than 6 months were treated with 25 mg of gold sodium thiomalate for an average of 29.6 weeks, then at biweekly or monthly intervals to complete 2 years of treatment. Thirty-eight patients were given more than twice as much gold salt at the same intervals on a flexible dose schedule that produced serum gold levels which averaged 332 microgram/dl during the weekly injection phase. No differences were observed in the therapeutic responses of the two groups. Therefore the minimal dose of gold sodium thiomalate required to induce a response in rheumatoid arthritis is 25 mg or less per week. Serum gold levels in the steady state varied between 95 and 386 microgram/dl and were not related to response. Serum half-life for gold was calculated for patients who had an excellent response and for those who were treatment failures. The rate at which gold disappeared from serum was not related to therapeutic responses.

Adolescent↗
PubMedDate not supplied

Cytogenetic studies on commercial hexane solvent.

Commercial hexane is a solvent mixture of six-carbon isomers, consisting principally of n-hexane, 3-methylpentane, methylcyclopentane and 2-methylpentane. The potential of commercial hexane to produce chromosome aberrations was evaluated in both an in vitro assay using Chinese hamster ovary (CHO) cells and an in vivo cytogenetics assay using Sprague-Dawley rats. The CHO cells were exposed to media containing commercial hexane at concentrations of 0.014-0.42 microliters ml-1 in the presence and absence of an S-9 activation mixture. Cellular toxicity was observed at the higher dose levels, but no increase in chromosome aberrations was observed in either the non-activated or S-9-activated systems. For the in vivo cytogenetics assay, rats were exposed nose-only for 6 h per day for 5 consecutive days to commercial hexane vapor at target concentrations of 900, 3000 and 9000 ppm. Bone marrow cells were collected at 6 and 24 h after the midpoint of the last exposure. Metaphase cells were examined microscopically for chromosome aberrations. No statistically significant increases in aberrant cells were observed in the commercial hexane-exposed animals of any dose group at either of the bone marrow harvest times. In conclusion, commercial hexane did not produce chromosomal mutations under the conditions of these studies.

Animals↗
PubMedDate not supplied

Two-generation reproduction study on commercial hexane solvent.

The reproductive effects of inhalation exposure to commercial hexane vapors were evaluated in Sprague-Dawley rats. Males and females were exposed to commercial hexane vapor at target concentrations of 0, 900, 3000 or 9000 ppm for 6 h a day, 5 or 7 days a week, over two generations. In addition to pre-breed exposures of 10 weeks' duration, exposures continued through mating, gestation and lactation. At both the F0 breed to produce F1 litters and the F1 breed to produce F2 litters, reproductive parameters were unaffected by commercial hexane exposure. The mating, fertility and gestational indices, as well as litter size and postnatal survival, were not significantly different between exposure groups. However, reductions in body weight and body weight gain were observed in both F1 and F2 litters exposed to 9000 ppm. Effects on body weight were not observed in offspring exposed to the two lower concentrations of commercial hexane. Histopathological examination of selected tissues revealed hyaline droplet nephropathy in adult F0 and F1 males exposed to 9000 ppm. This finding was anticipated and is not believed to be relevant for the assessment of human health effects. No other treatment-related histopathological lesions were observed. Thus, exposure of rats to commercial hexane for two generations resulted in reduced body weight gains at 9000 ppm but no adverse effects on reproduction. These findings suggest that occupational exposure to commercial hexane vapors at currently recommended threshold limit value concentrations (i.e. TLV for n-hexane is 50 ppm and TLV for other hexane isomers is 500 ppm) should not pose a reproductive hazard.

Administration, Inhalation↗
PubMedDate not supplied

Balancing the books.

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Coronary Disease↗
PubMedDate not supplied

Quantitative evaluation of the stability and delivery of interleukin-1B by infusion.

The stability and delivery of IL-1 beta has been characterized in a polypropylene based syringe pump infusion system and in polyvinyl chloride based infusion bags, at concentrations ranging from 100 ng/mL to 1 microgram/mL. At higher concentrations (1 microgram/mL), minimal drug loss was observed in both systems. At low doses (100 ng/mL) in the syringe-pump system, the addition of 1% human serum albumin was necessary to prevent significant drug absorption to the polypropylene drug reservoir.

Adsorption↗