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Biomedical subjects

R D Smith

Publications and source records attributed to R D Smith.

At least 451 records · Page 25Linked to original sources
PubMed1979

Evaluation of an improved rapid coagglutination method for the serological grouping of beta-hemolytic streptococci.

Grouping of beta-hemolytic streptococci was performed with the Phadebact Streptococcus Test, a coagglutination method, and the results compared with serological grouping by the standard Lancefield precipitin method. Of 171 clinical specimens examined, 169 (98.8%) were grouped correctly by the Phadebact Test after 24 h of continuous growth in Todd-Hewitt broth. In a parallel study, 96.9% of specimens that grew after only 4 h of incubation in broth were grouped correctly by the coagglutination method. In both studies, the accuracy of the coagglutination test was increased significantly by elimination of multiple-agglutination reactions through centrifugation of cultures and utilization of the supernatant fluid in the Phadebact Test.

Agglutination Tests↗
PubMed1979

Prolactin binding to dissociated cells from rat mammary tumors and mammary gland.

Prolactin binding activity was studied in suspensions of cells which had been enzymatically dissociated from R3230AC mammary tumors, 7,12-dimethylbenz(a)anthracene (DMBA)-induced mammary tumors and lactating rat mammary glands. Prolactin bound specifically with high affinity (apparent binding affinity = 4.0 X 10(9) M-1) to R3230AC tumor cells. Hormone binding at room temperature was proportional to cell number and increased with time of incubation up to 120-180 min. Prolactin binding to R3230AC tumor cells from diabetic animals was reduced by about 50%. Specific prolactin binding activity was also demonstrated in preparations of cells from DMBA-induced tumors and lactating mammary gland. The levels of hormone binding in both dissociated cells and subcellular particles prepared from these tissues varied as follows: DMBA-induced tumors > lactating mammary gland > R3230AC mammary adenocarcinoma.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1979

Schedule shifts, life quality and quantity--modeled by murine blood pressure elevation and arthropod life span.

During the span from 50 to 100 days and beyond, the male stroke-prone Okamoto rat develops systolic blood pressure measures in excess of 200 mm Hg. In the course of developing such a marked elevation in systolic blood pressure mean, this intermittently handled male Okamoto rat exhibits a statistically significant circadian rhythm with large amplitude. This amplitude may represent, at least in part, a response to intermittent handling; it is several times larger than the amplitude for spontaneously mesor-hypertensive (but not stroke-prone) female animals of the same age.

Aging↗
PubMed1978

The use of developmental screening tests by primary-care pediatricians.

Two-hundred-twenty-two pediatricians were surveyed to determine the use of developmental screening tests in primary-care pediatrics. Sixty-three percent of the 121 primary care pediatricians responding to this survey reported that they use developmental screening tests, but only 15 to 20% screen more than 10% of their patients with these tests. Factors associated with the use of developmental screening tests included the year of graduation from medical school, level of postinternship training, duration of current practice, training in the use of tests as a house officer or fellow or at postgraduate seminars, and belief that the use of developmental screening is a necessary part of routine health maintenance. Pediatricians use developmental screening tests infrequently and, probably, only after evidence of developmental delay has been established by other criteria.

Attitude of Health Personnel↗
PubMed1978

Growth of Babesia bovis in bovine erythrocyte cultures.

Babesia bovis was cultured in a suspension of bovine erythrocytes incubated at 37 degrees C in Medium 199 with 50% bovine serum. The cells in culture were kept in suspension by slow stirring in spinner flasks and the medium was replaced at 24-hour intervals. Persistent multiplication of the parasite in a short series of subcultures suggests the feasibility of this approach for continuous culture.

Animals↗
PubMed1978

Rest therapy for rheumatoid arthritis.

Rest therapy in rheumatoid arthritis has long been controversial. Available evidence indicates that exercise increases joint inflammation and destruction and rest reduces inflammation. Hospitalization may produce improvement in inflammation, which is sometimes marked. Fatigue, a frequent and often prominent symptom of rheumatoid arthritis, is a guide to therapy. Sufficient rest to prevent fatigue combined with appropriate physical therapy would be expected to improve the treatment of rheumatoid arthritis.

Arthritis, Rheumatoid↗
PubMed1978

Bovine babesiosis: severity and reproducibility of Babesia bovis infections induced by Boophilus microplus under laboratory conditions.

A total of 61 intact Holstein-Friesian calves were exposed to Babesia bovis (= B argentina) by the injection of infected blood or the application of infected Boophilus microplus larvae. Tick-induced infections were uniformly severe, even when induced by relatively small numbers of infected ticks. In contrast, calves infected with carrier blood experienced mild, subclinical reactions despite detectable parasitaemia. The greater severity of tick-induced reactions appeared to be due to the large number of infective doses injected by each infected tick rather than greater virulence of tick versus blood-origin babesiae. The severity of tick-induced babesiosis was related to the age of the experimental calves, with more severe reactions and high mortality occurring among older animals. The mean daily temperature rise increased with age and was highest in 15 animals dying of babesiosis. No relationship could be found between peripheral blood parasitaemia, packed cell volume reduction and mortality in tick-induced infections. One thousand larvae from infected colonies induced babesiosis in all of 29 animals exposed. Although larval transmission of B bovis is difficult to quantitate, there would seem to be no objection to using a controlled tick-borne challenge in the laboratory for assessment of susceptibility.

Animals↗
PubMed1977

Prolactin binding to R3230AC mammary carcinoma and liver in hormone-treated and diabetic rats.

Specific 125I-labeled prolactin binding was measured in membrane particles prepared from R3230AC mammary carcinoma and liver of tumor-bearing Fischer rats after either prolactin, estrogen, or lergotrile mesylate treatment, or after the induction of diabetes by streptozotocin. Hormone binding to tumors was decreased by treatment with prolactin (0.5 or 1 mg/day) or estradiol valerate (7.5 mg/kg/week). In contrast, prolactin treatment did not affect prolactin binding to liver membrane particles, but estradiol valerate treatment resulted in a four-fold increase in prolactin binding to this tissue. Lergotrile mesylate, which lowers plasma prolactin levels, did not affect tumor growth or prolactin binding to either tumor or liver. Prolactin binding to both tumor and liver was significantly reduced in diabetic rats, suggesting that insulin may play an important role in controlling tissue sensitivity to prolactin. Specific binding of 125I-labeled prolactin to enzymatically dissociated cells from R3230AC tumors was demonstrated in vitro. The binding capacity of the cells was found to be of the same order of magnitude as the binding capacity in membrane preparations when appropriate corrections were applied for yields of cells and membranes. R3230AC tumor, which is responsive to prolactin appears therefore to be a useful model system for further study aimed at elucidation of growth and metabolic response to the hormone prolactin in breast cancer.

Acetonitriles↗
PubMed1977

Prolactin binding to 7,12-dimethylbenz(a)anthracene-induced mammary tumors and liver in diabetic rats.

Growth rates of 7,12-dimethylbenz(a)anthracene-induced mammary tumors and the specific 125I-labeled prolactin binding to membrane fractions prepared from livers and tumors were studied in rats made diabetic by streptozotocin injection. Growth was inhibited in a majority of tumors and prolactin binding was reduced in both tumors and livers from diabetic animals. Prolactin binding to individual tumors varied over a wide range in both intact and diabetic animals. Scatchard analysis of binding data revealed that the apparent affinity of prolactin binding to liver and tumor membranes was similar (Ka approximately 3.0 X 10(9) M-1) and was not affected by diabetes. We suggest that the reduction in prolactin binding to tumors may render these tissues less responsive to prolactin and thereby explain, at least in part, the observed inhibition of tumor growth in diabetic rats. However, some tumors in diabetic animals regressed despite relatively high levels of prolactin binding activity. Therefore, additional factors most certainly play important roles in the mechanism(s) by which the growth of 7,12-dimethylbenz(a)anthracene-induced tumors is impaired in the diabetic rat.

9,10-Dimethyl-1,2-benzanthracene↗