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Biomedical subjects

F A Smith

Publications and source records attributed to F A Smith.

At least 55 records · Page 3Linked to original sources
PubMed1981

One-year survey of enteroviruses, adenoviruses, and reoviruses isolated from effluent at an activated-sludge purification plant.

Samples of raw sewage, primary effluent, and secondary effluent from a large activated-sludge purification plant near Melbourne (Victoria, Australia) were collected every second week for 1 year. Viruses were detected in all secondary effluent samples and in six of seven samples obtained after final chlorination. Adenoviruses (85% reduction) and reoviruses (28% reduction) were removed less efficiently by this treatment process than were enteroviruses (93% reduction). In addition, 57 of 171 samples of effluent tested were positive for either adenoviruses or reoviruses, or both, when enteroviruses were not isolated. This clearly shows that the use of enteroviruses as sole indicators of viruses in water may miss up to one-third of instances of viral contamination. Enteroviruses and adenoviruses were isolated most frequently in HeLa-R cell cultures, whereas reoviruses were most often isolated in primary monkey kidney cells.

Adenoviridae↗
PubMed1981

Vinyl chloride: inhalation teratology study in mice, rats and rabbits.

These studies evaluated the effects of inhaled vinyl chloride monomer (VCM) on mouse, rat and rabbit embryonal and fetal development. Groups of pregnant CF-1 mice, Sprague-Dawley rats and New Zealand white rabbits were exposed to 500 ppm VCM for 7 hr daily during the period of major organogenesis. Subsequently, other groups of mice were similarly exposed to 50 ppm VCM, and rats and rabbits were exposed to 2500 ppm. While maternal toxicity was observed, exposure to VCM did not cause significant embryonal or fetal toxicity and was not teratogenic in any of the three species at the concentrations tested. Simultaneous exposure of some of the pregnant animals to VCM by inhalation plus 15% ethanol in the drinking water resulted in toxic effects greater than those associated with exposure to VCM alone in the three species. The fetal effects observed were similar to those reported for these three species following administration of ethanol without VCM exposure.

Abnormalities, Drug-Induced↗
PubMed1981

A multiaperture collimator for use at 511 keV.

Positron-emitting radionuclides are being used more and more in nuclear medicine. This paper describes a high energy collimator suitable for imaging at 511 keV, the energy emitted by these radionuclides, for use with the Baird Corporation's System 77.

Gamma Rays↗
PubMed1981

Styrene epoxide intermediate as a possible stimulant of lymphocytic function.

Mice treated with styrene showed an increased lymphocyte transformation in splenic cell cultures. The effects were observed both on spontaneous transformation and phytomitogen induced blast formation. Addition of styrene oxide directly to splenic cultures, but not of styrene, increased blast formation at low concentrations but was cytotoxic at high concentrations. In this test system styrene exhibited a generalized immunostimulation. In vitro data suggest that this effect of styrene is mediated possibly through its conversion to styrene oxide, its transient metabolic intermediate.

Animals↗
PubMed1980

Estimation of the postmortem interval by chemical means.

The literature is reviewed regarding estimation of the postmortem interval (PMI) by chemical analysis of cadaver fluids. The most useful measurements on blood and CSF are amino nitrogen, nonprotein nitrogen, ammonia, creatine, and inorganic phosphate; these have some value in the early PMI. Probably the single most accurate determination is the potassium content of the vitreous humor, which shows a linear rise with time in the interval 12-100 hours postmortem. The rate of vitreous potassium rise is fairly independent of environmental influence. Other determinations that may prove valuable include the potassium content of the aqueous humor and the ammonia and magnesium content of the vitreous. Although no single measurement gives a completely reliable estimate of the PMI, combinations of chemical determinations can be useful adjuncts in cases of unwitnessed death.

Ammonia↗
PubMed1979

Teratogenic potential of inhaled carbon monoxide in mice and rabbits.

Pregnant CF-1 mice and New Zealand rabbits were exposed to carbon monoxide at a concentration of 250 ppm for 7 or 24 hours daily during the period of major organogenesis, days 6 through 15 of gestation in mice and 6 through 18 of gestation in rabbits. Carboxyhemoglobin levels in the range of 10--15% were observed in both species (control animals had 0.7% or less). Carbon monoxide was not found to be teratogenic in either species. In mice, a significant increase in the incidence of some minor skeletal variants was observed. One litter in each of the carbon monoxide-exposed groups of mice was completely resorbed; none of the litters of control mice or of control or exposed rabbits were completely resorbed. The fetuses of mice exposed to carbon monoxide for seven hours daily were heavier than control fetuses, and those exposed for 24 hours daily were lighter than control fetuses. The reason for this result is not known.

Abnormalities, Drug-Induced↗
PubMed1979

Effects of fluoroacetate on the testis of the rat.

Rats recieving 20, 6.6 or 2.2 p.p.m. sodium fluoroacetate in the drinking water were killed daily during the 7 days of treatment and at more widely spaced intervals in the succeeding 21 days. Testicular weight and ATP concentrations decreased in rats receiving 20 or 6 p.p.m. fluoroacetate, while citrate concentrations were elevated and morphological damage was seen in the testes of all the treated rats. Initial cellular changes common to the three treatment groups included altered appearance and decreased numbers of spermatids, and formation of spermatid and spermatocyte giant cells. At the two higher concentrations damage progressed to marked seminiferous tubule atrophy. Regeneration of the seminiferous tubules was complete by 7 days after treatment, in the rats given 2 p.p.m. but regeneration was not complete by Day 21 after treatment in those receiving the higher doses. Spermatogenesis was abnormal in some instances during the regneration period in these groups. The findings are consistent with impaired energy production via blockage of the Krebs cycle, and subsequent impairment of carbohydrate metabolism through the Embden-Meyerhof pathway.

Adenosine Triphosphate↗