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Biomedical subjects

A Leonard

Publications and source records attributed to A Leonard.

25 records · Page 2Linked to original sources
PubMed1976

The radiosensitivities of lymphocytes from pig, sheep, goat and cow.

Dose-effect curves for X-irradiation in vitro were determined on cultured blood lymphocytes of four mammalian species-cow, goat, sheep and pig-having approximately the same number of chromosome arms, the same nuclear volume and the same DNA content. The data from cow, but not those from the other species, exhibited significant inhomogeneity between the experiments. On inspection the numerical yields appear not to differ greatly in the lower dose range. Evaluation of the parameters according to the quadratic law and the power law, however, demonstrate significant differences. Pig differs from the other species regardless of which presentation is chosen. For the power law a significant difference is also found between goat and sheep.

Animals↗
PubMed1976

Action of lead on early divisions of the mouse embryo.

The number of cells in mouse embryos 48 h after mating was studied in normal and lead-treated females (0.125, 0.25, 0.5, 1% of lead in the diet). The percentage of embryos in the 4-cell stage compared to those in the 8-cell stage increased after 0.125, 0.25 and 0.5% of dietary lead. After the highest dose an increase in nondivided eggs was also seen which occurred at the expense of 4-cell embryos. The different possibilities, delay of all divisions, delay of only the first division and action of lead on only a part of the embryonic population, are discussed.

Animals↗
PubMed1976

[Chromosome modifications induced in mouse spermatogonia through exposure to high-energy neutrons].

The incidence of reciprocal translocations induced in mouse spermatogonia has been studied in CBA mice given X-ray or neutron exposure. Analysis of dividing spermatocytes at diakinesis-first metaphase stage of meiosis shows that in X-irradiated mice there is a linear dose-response relationship. After exposure to fast neutrons the yield of translocations follows a humped curve with a maximum of chromosome exchanges after exposure to 100 rad.

Animals↗
PubMed1976

[Study of chromosome characteristics of artificially-induced ascite tumors].

Some ascite tumours have been induced in rat by intraperitoneal injection of RadLV and in mouse by intraperitoneal injection of RadLV, or of protozoa such as Trypanosoma brucei and Toxoplasma gondii. Cytological examination of the resulting ascite tumours has shown that chromosome aberrations were associated with the presence of C and A viral particles.

Animals↗
PubMed1975

Subdural hematoma in regularly hemodialyzed patients.

Thirteen of 394 (3.3%) regularly dialyzed patients of the Regional Kidney Disease Program developed subdural hematoma. The following factors contributed to formation of subdural hematoma: head trauma, ultrafiltration to control excessive accumulation of fluid and hypertension, anticoagulants, and frequent vascular access infection and clotting. Neurologic symptoms and signs, which may be similar to dialysis disequilibrium, aid only in signifying the presence, not the ultimate localization, of subdural hematoma. Our experience underscores the frequency of bilateral disease, irrespective of neurologic findings. Skull films, lumbar puncture, and electroencephalography were of little diagnostic help. Although valuable and safe, brain scanning was not as useful as desired due to occurrences of false-negative studies and failure to identify bilaterality of lesions. Cerebral angiography was always diagnostic. Surgical intervention yielded disappointing results, and only 2 patients (15%) survived. A review of 9 other patient reports is included.

Adult↗