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Biomedical subjects

D J Tinston

Publications and source records attributed to D J Tinston.

9 recordsLinked to original sources
PubMed1988

Olfactory and hepatic changes following inhalation of 3-trifluoromethyl pyridine in rats.

Rats exposed by inhalation to 3-trifluoromethylpyridine (3-FMP) for 10, 30 or 90 days showed an unusual response in the nasal passages. Focal histological change including reduction in the number of cell layers, disorganisation, vacuolation and minimal necrosis was confined to the olfactory epithelium. Axon bundles and the olfactory bulb were unaffected but there was loss of PAS staining affinity in Bowman's glands. The onset of the lesion showed a very steep dose-relationship approximating a quantal response; no effects were seen after 90 days exposure to 0.1 ppm but the changes were fully developed after 30 days exposure to 0.5 ppm. There was no marked progression with either increased exposure concentrations (up to 329 ppm) or with increased duration of exposure (10-90 days). The respiratory epithelium was generally unaffected apart from a mild irritant response seen only after 90 days. Exposures also resulted in a response in the liver. Centrilobular and midzonal vacuolation was observed at 10 and 30 days following exposures at or above 5 ppm 3-FMP and the severity increased with concentration. The lesion regressed with time even when exposure continued and only minimal changes were evident after 90 days, probably indicating an adaptive response. This work demonstrates the high organ specificity of 3-FMP, particularly for the olfactory epithelium.

Administration, Inhalation↗
PubMed1988

Assessment of the reproductive toxicology of bromochlorodifluoromethane (BCF, halon 1211) in the rat.

The effect of bromochlorodifluoromethane (BCF) on reproduction in the rat has been investigated in two studies. Pregnant female rats were exposed by inhalation to 1000, 10,000, or 50,000 ppm BCF for six hours a day on days six to 15 of gestation (day of mating = day 0). Exposure to 50,000 ppm BCF caused a reduction in maternal weight gain over the exposure period but there was no evidence of either teratogenicity or embryo/fetotoxicity at any concentration. In a study designed to assess the potential effect of BCF during a complete reproductive cycle male and female rats were exposed to 5000 ppm or 25,000 ppm BCF for six hours a day for five days a week for 10 weeks (males) or three weeks (females) before mating. Exposure to BCF continued during mating and up to day 20 of gestation for half the females which were subsequently allowed to litter and the development of their offspring monitored. The remaining females were removed from exposure to BCF after mating and killed on day 20 of gestation for examination of their uterine contents. There were no effects on adult fertility, pup numbers, survival, or pup development. It was concluded that BCF had no reproductive toxicity potential in the rat.

Abnormalities, Drug-Induced↗
PubMed1984

The effects on the rat testis of single inhalation exposures to ethylene glycol monoalkyl ethers, in particular ethylene glycol monomethyl ether.

The effects of a single inhalation exposure to the rat of the saturated vapours derived from four ethylene glycol monoalkyl ethers have been investigated. No effects on the testis were observed following exposure to ethylene glycol isopropyl ether (EG ISOPE) and ethylene glycol butyl ether (EGBE), but there were marked reductions in testicular weight 14 days after exposure to ethylene glycol monomethyl ether (EGME) and ethylene glycol monoethyl ether (EGEE). Further studies were designed to establish the effect of a single exposure to EGME. Mature male albino rats were exposed to various levels of EGME vapour for a single 4-h period and killed 14 days later. Following this single exposure a dose-related decrease in testis weight was observed in rats exposed to 5,000, 2,500 or 1,250 ppm EGME. Histopathological examination revealed disordered spermatogenesis and tubular atrophy in these animals. Minimal degenerative changes were seen in the testis of rats exposed to 625 ppm EGME. When rats were examined at various time intervals after exposure to EGME vapour for 4 h, testis weight was reduced in rats examined 2 days after exposure to 2,500 and 1,000 ppm EGME and remained depressed when compared with control values for up to 19 days following exposure. Histopathological examination of the testis revealed disordered spermatogenesis in exposed animals evident at 1 day following exposure to either 2,500 or 1,00 ppm EGME.

Animals↗
PubMed1983

Comparative aspects of the reproductive toxicology by inhalation in rats of ethylene glycol monomethyl ether and propylene glycol monomethyl ether.

This study was designed to provide a rapid assessment of the effect of two glycol ethers on some aspects of reproduction in the rat. Exposure was by inhalation at 100 and 300 ppm (EGME) and 200 and 600 ppm (PGME) for 6 hr/day. The study was in two parts: (a) Pregnant females were exposed on Days 6 to 17 of gestation. Body weight gain was reduced in both EGME groups. No litters were delivered in the 300-ppm EGME group and only 9/20 rats in the 100-ppm EGME group produced litters where the number, weight, and viability of the pups were reduced, but the pups appeared normal externally. Exposure at 200 and 600 ppm PGME had no effect. (b) Male rats were exposed for 10 days. There was a reduction in testicular weight accompanied by semeniferous tubular atrophy in the 300-ppm EGME group. There were no effects at 100 ppm EGME or 200 and 600 ppm PGME. 300 ppm EGME caused significant reductions in white blood cell count, red blood cell count, hemoglobin concentration, hematocrit, and mean cell hemoglobin. The study design proved capable of demonstrating the effects of EGME on the testes and on fetal development and highlighted PGMEs lack of activity at the doses tested.

Animals↗
PubMed1982

Acute inhalation toxicity of some halogenated and non-halogenated hydrocarbons.

1 The relative potency of effect of a wide range of halogenated and unsubstituted hydrocarbons on the central nervous system (CNS) and the heart of experimental animals have been determined. 2 The chemicals used caused either stimulation or depression of the rat CNS after 10 minutes' inhalation of concentrations ranging from 0.24% to greater than 80% (v/v), and cardiac sensitization in dogs after 5 minutes' inhalation of 0.12% to approximately 80% (v/v). 3 The toxicity could not be correlated with chemical structure, molecular weight, the presence or absence of various halogen atoms or the degree of saturation, but it was inversely related to the saturated vapour pressure. When the results were expressed on a thermodynamic scale the chemicals had similar potencies at relative saturations of 0.004 to 0.04 4 It is suggested that the effects of these chemicals on the CNS and the heart are probably structurally non-specific, and the chemicals may be regarded as physical toxicants whose effects are predictable from their physico-chemical properties.

Animals↗
PubMed1973

Correlation of the cardiac sensitizing potential of halogenated hydrocarbons with their physicochemical properties.

The cardiac sensitizing potencies of a range of 14 halogenated hydrocarbons were assessed in conscious dogs by comparing the partial pressures (Pcs) needed to sensitize the heart to adrenaline. These were found to be directly related to their saturated vapour pressures (Ps) and the ratio Pcs/Ps was approximately constant although the values of partial pressures differed nearly 700-fold. It is suggested that cardiac sensitization is probably a structurally non-specific action and may be regarded as another example of physical toxicity.

Anesthetics↗