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Biomedical subjects

B Richardson

Publications and source records attributed to B Richardson.

At least 145 records · Page 8Linked to original sources
PubMed1978

Hepatitis in undertakers.

Six of 106 undertakers (5.6%) gave a past history of hepatitis during their professional careers; this was no different from the frequency in a control group of 3,162 accountants (5.1%) who had no direct contact with blood. None of the undertakers or 210 blood donors matched for age, sex, and ethnic background had serum positive for hepatitis B surface antigen. Five undertakers (4.7%) had blood that was positive for antibody to hepatitis B surface antigen, compared with six of 210 (2.9%) in the control group; this difference was not statistically significant (P greater than .25). Thus, undertakers appear to be in a low-risk occupation with reference to acquisition of hepatitis B. Although the numbers are too small for statistical analysis, there appeared to be an increased exposure to hepatitis B in undertakers who take no preventive precautions. We recommend that the minimal precautions for undertakers be the wearing of gloves.

Adult↗
PubMed1977

Complementary idiotypy in the regulation of the immune response.

A new concept is presented for the interactions of two complementary antibodies in the immune response. These antibodies bind to each other by means of their variable sequence determinants and therefore are designated as complementary idiotypes. Under certain conditions, both complementary idiotypes are produced by the same animal at the same time. An idiotype can drastically affect the expression of the complementary idiotype in the animal, inducing a peripheral quench effect of antibody-binding activity and a central effect on the immunocompetent cell, which produces the complementary idiotype. It is proposed that complementary idiotypes might be induced during every immune response, thus playing an essential role in the regulation of the immune response.

Animals↗
PubMed1976

The role of prolactin in the development of chronic progressive nephropathy in the rat.

Prolactin as a factor in the etiology of chronic progressive nephropathy in rats has been studied by exogenous administration and by endogenous inhibition with bromocriptin. Exogenous prolactin caused a significant increase in frequency and severity of the lesions, with accompanying sodium retention. Conversely endogenous inhibition significantly decreased the frequency and severity of the lesions and increased urine volume, pH and sodium excretion. Thus prolactin is important in the etiology of this renal disease in rats.

Aging↗
PubMed1976

Studies on human malaria in Aotus monkey. VII. Comparative infectivity of two strains of Plasmodium vivax to to Anopheles freeborni, A. maculatus, and for strains of A. albimanus.

A strain of Plasmodium vivax from El Salvador was shown to be more infectious to the Apastepeque strain of Anopheles albimanus from El Salvador than was a strain of P. vivax from Colombia, S. A. The Apastepeque mosquito strain was also more susceptible to the Savadoran strain of P. vivax than were 2 other strains of this mosquito from El Salvador. A strain of A. albimanus from Panama was more susceptible to both of the parasite than were any of the Salvadoran strains of A. albimanus.

Animals↗
PubMed1975

Localization of prolactin in rat kidney tissue using a double-antibody technique.

A fluorescein-labelled double-antibody technique was used for the microscopical localization of ovine prolactin in kidney tissue of rats previously injected intravenously with 50 i.u. of the hormone at varying intervals before death. Thirty seconds after the injection, the hormone could already be visualized in teh lumina of the proximal tubules. After 2 min, discrete praticulate fluorescence appeared on the brush border of the epithelium of the proximal tubules. Three minutes later prolactin was clearly localized in the apical portion of the cytoplasm of these cells as well as on the brush border. Ten minutes after the injection, the hormone appeared exclusively within the cell, highest concentrations being observed in the perinuclear region. After 20 min, however, the hormone appeared evenly distributed throughout the cytoplasm. The distributtion of prolactin was in all cases confined to the proximal tubular region of the nephron. The findings support the suggestion that the site of action of prolactin in the kidney is the epithelium of the proximal tubule. As prolactin was first visualized in the lumen of this portion of the nephron, it appers that the hormone gains access to these cells via the glomerular filtrate.

Animals↗
PubMed1975

Prevention of decompression sickness during a simulated space docking mission.

This study has shown that repetitive exchanges between the American Apollo space vehicle atmosphere of 100% oxygen at 5 psia (258 torr) and the Russian Soyuz spacecraft atmosphere of 30% oxygen-70% nitrogen at 10 psia (523 torr), as simulated in altitude chambers, will not likely result in any form of decompression sickness. This conclusion is based upon the absence of any form of bends in seven crewmen who participated in 11 tests distributed over three 24-h periods. During each period, three transfers from the 5 to the 10 psia environments were performed by simulating passage through a docking module which served as an airlock where astronauts and cosmonauts first adapted to each other's cabin gases and pressures before transfer. Biochemical tests, subjective fatigue scores, and the complete absence of any form of pain were also indicative that decompression sickness should not be expected if this spacecraft transfer schedule is followed.

17-Hydroxycorticosteroids↗
PubMed1969

Growth of Chlorella sorokiniana at hyperbaric oxygen pressures.

The growth rate of Chlorella sorokiniana decreased in a linear fashion as the partial pressure of oxygen was increased from 711 to 1,478 mm of Hg. Under two atmospheres of oxygen pressure, growth ceased after 10 to 12 hr. This cessation of growth was not due to any permanent injury, as growth resumed when oxygen partial pressure was reduced to ambient levels. The inhibition occurred under both autotrophic and heterotrophic growth conditions and was not accompanied by an increase in cell size. The results indicated that the tolerance of Chlorella cells to elevated oxygen pressures was not an absolute immunity, and that inhibition of growth at very high oxygen pressures cannot be accounted for by an inhibition of photosynthesis alone.

Eukaryota↗
PubMed1969

Effects of nitrogen limitation on the growth and composition of unicellular algae in continuous culture.

Since fat accumulation takes place in many algae as a response to exhaustion of the nitrogen supply, it has been suggested that this may provide a means of enhancing the potential food value of algae. To test this possibility, chemostatic continuous cultures of Chlorella sorokiniana and Oocystis polymorpha were subjected to successive reductions in influent nitrogen. As cellular nitrogen content decreased from about 10 to 4%, oxygen evolution, carbon dioxide uptake, chlorophyll content, and tissue production were drastically reduced, but total lipid content was essentially unchanged. Caloric values and C, H, and N analyses suggested a moderate increase in carbohydrate content, but gas chromatographic analyses revealed no significant qualitative or quantitative changes in the fatty acid fraction. In batch-cultured cells, nitrogen could be reduced to 3% of dry weight, causing a concomitant increase in total fatty acids and pronounced changes in the composition of the fatty acid fraction. These results suggest that cellular nitrogen must fall to approximately 3% of dry weight before appreciable increases in lipid synthesis can occur. Cell nitrogen is then apparently completely bound in essential cell constituents, and carbon subsequently fixed is converted into lipid products. The findings indicate that nitrogen limitation may be useful in increasing the food quality of batch-cultured cells, but the technique has little value for continuous culture systems per se.

Journal Article↗