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Biomedical subjects

R C King

Publications and source records attributed to R C King.

At least 73 records · Page 4Linked to original sources

Giant polytene chromosomes from the ovaries of a Drosophila mutant.

The chromosomes of the ovarian nurse cells of Drosophila melanogaster fall apart during their cycles of endoreduplication. However, chromosomal synapsis occurs in the pseudonurse cells produced in certain mutant females. The resulting polytene chromosomes undergo developmental changes that are strikingly different from those recorded for the giant chromosomes of the larval salivary gland cells.

Animals↗

Drug therapy review as part of a medical audit process.

A method of chart review that focuses on the role of drugs as both therapeutic and iatrogenic agents in the sum of health care given to a patient is presented. A team of 11 to 16 health care professionals evaluated ambulatory health care systems funded by HEW. All clinician evaluators participated in the medical audit segment of the evaluation. Drug therapy review was based on an assessment of the relationship between patient, drug and other factors. Discussed also are the nine assessment options open to the evaluator and the mechanisms used to incorporate findings into the larger system review process. A by-product of the use of this process was increased prescribed-pharmacist cooperation and contribution in performance of the medical audit.

Ambulatory Care↗

Evidence for dosage compensation in parthenogenetic Hymenoptera.

Amounts of DNA-Feulgen staining in individual somatic nuclei and mature sperm of the parthenogenetic wasps, Habrobracon juglandis, H. serinopae, and Mormoniella vitripennis, were determined with a scanning microdensitometer. The haploid genome for both species of Habrobracon was estimated to be 0.15-0.16 X 10-(12) gDNA, corresponding to a molecular weight of roughly 10 X10(10) daltons. The haploid genome of M. vitripennis is approximately twice this value, 0.33-0.34 X 10-(12) g, or about 20X10(10) daltons. Measurements made on dividing nuclei from syncytial preblastoderm embryos of H. juglandis and M. viripennis showed that the chromosomes of impaternate males were present in the haploid number and contained the C amount of DNA; whereas nuclei from female preblastoderm embryos contained the diploid number of chromosomes and the 2C amount of DNA. However, hemocyte and brain cell nuclei from either male or female adult wasps contained 2C and 4C amounts of DNA. Both sexes also showed equivalent levels of polyploidy (8C, 16C, or 32C) in Malpighian tubule nuclei. Therefore, in these parthenogenetic species,, a mechanism must exist the compensates during later development for the initial two-fold difference in the chromatin content of somatic nuclei in haploid male and diploid female embryos. Hemocytes from impaternate Mormoniella diploid males and triploid females contain the 2C and 3C amounts of DNA, respectively Therefore dosage compensation involves an additional cycle of DNA replication only in hapoid cells, and it insures that a certain minimum quantity of DNA is received by each somatic cell.

Animals↗

Oogenesis in the female sterile (1)42 mutant of Drosophila melanogaster.

The sex-linked mutation fs(1)42 was induced by ethyl methane sulfonate. It has no effect on either the external morphology or longevity of adult hemizygotes or homozygotes. Heterozygotes and hemizygotes are fertile, but homozygotes are sterile. Egg chamber development proceeds through stages 8, and thereafter chambers degenerate. Dying follicle cells are seen in chambers at all positions in the ovarioles. Profollicle cells also die within germaria, and clusters of sister cystocytes take longer than normal to receive their coverings of follicle cells. Egg chambers in the vitellarium contain only about 60% the normal number of follicle cells, these generally have greater lateral dimensions, and their nuclei and nucleoli are also larger than normal. The follicular envelope of mutant chambers often contains gaps through which cystocytes send cytoplasmic projections. Abnormalities seen in development of the fs(1)42 oocyte are likely to be due to its envelope of defective follicle cells.

Animals↗

A new automated procedure for serum inorganic phosphorus.

1. The method of Parekh and Jung for determination of inorganic phosphorous in serum has been adapted for automation. One of the assets of the method is its unusually stable reagents. The automated procedure is highly accurate, sensitive, rapid and economic. Its other advantages are discussed in light of the literature.

Autoanalysis↗

The penetration of dapsone, rifampicin, isoniazid and pyrazinamide into peripheral nerves.

1 Dapsone, rifampicin, isoniazid and pyrazinamide were shown to penetrate readily into the sciatic nerves of the dog and sheep. 2 These findings suggest that the continued persistence of viable drug-sensitive leprosy bacilli in the peripheral nerves of patients treated for long periods with either dapsone or rifampicin is not due to inadequate intraneural drug penetration.

Animals↗

Bacteremia after tooth extractions studied with the aid of prereduced anaerobically sterilized culture media.

Both prereduced molten agar and broth and aerobic molten agar and broth were inoculated with blood samples collected from patients with periodontitis, but in otherwise good health, both before and after extraction of two or more teeth. Postoperative blood samples from 23 of 25 patients sampled yielded anaerobic and facultative species. Colony counts from nine samples yielded from less than 1 to over 100 colonies per ml of blood. Organisms detected were species belonging to the genera Bacteroides, Fusobacterium, Peptostreptococcus, Leptotrichia, Propionibacterium, Peptococcus, Veillonella, plus Streptococcus mitis, S. salivarius, vibrio forms, and strains resembling S. mutans. The data indicate that prereduced anaerobically sterilized culture medium with polyanethol sulfonate is effective for detecting anaerobic species in bacteremia and that anaerobic species can be prevalent in bacteremias immediately after tooth extraction in patients with periodontitis.

Aerobiosis↗