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Biomedical subjects

M Davidson

Publications and source records attributed to M Davidson.

At least 361 records · Page 20Linked to original sources
PubMed1982

A title VI view of child welfare issues.

The passage of the Civil Rights Act of 1964 was intended primarily to prohibit segregation in publicly funded schools. Its provisions, however, have an impact far beyond educational institutions, since Title VI of this act prohibits discrimination in all programs receiving federal financial assistance. Compliance reviews are being conducted, and the authors examine several long-standing concerns of child welfare professionals from the perspective of Title VI.

Adoption↗
PubMed1981

Immunogenic effect of inactivated hepatitis B vaccine: comparison of 20 microgram and 40 microgram doses.

The immunogenic effect of inactivated hepatitis B vaccine (Merck Heptavax B) was evaluated in 202 seronegative healthy medical personnel. Three inoculations of vaccine were given at 1-month intervals. Of 116 vaccinees who received a 40-microgram dose, 39% had an anti-HBs response 1 month after the first dose, 88% 1 month after the second dose, and 99% 1 month after the third dose. Of 86 vaccinees who received a 20 microgram dose, 40% had an anti-HBs response 1 month after the first dose, 79% after the second dose, and 95% after the third dose. These results confirm the high immunogenic effect of a 20-microgram dose of vaccine.

Adult↗
PubMed1981

Accidental hypothermia: a community hospital perspective.

Hypothermia, especially in an urban environment, is often an unsuspected and therefore underdiagnosed clinical entity. Of 60 cases recorded over a two-year period in a typical community hospital in Philadelphia, 26 (43%) involved patients under 60 years of age; ambient air temperatures at admission exceeded 50 F (10 C) in 28 (47%) of the 60 cases. Hypothermia thus cannot necessarily be attributed to advanced age or cold climates or seasons. The severity of hypothermia did not correlate with either the season of the year or the ambient air temperature. Diabetes and alcohol abuse appear to be risk factors for hypothermia, being present in 18 (30%) and 14 (23%) of our patients, respectively. Every emergency department should have a protocol for identification and management of the hypothermia victim to allow timely institution of appropriate rewarming techniques.

Accidents↗
PubMed1981

Repair of strand breaks in superhelical DNA of ataxia telangiectasia lymphoblastoid cells.

A number of different assay methods have been used to study repair of strand breaks in DNA after exposure of cells to ionizing radiation. Use of these methods indicates that fibroblasts from patients with ataxia telangiectasia (AT), a multiform genetic disease exhibiting high sensitivity to ionizing radiation, have a normal ability to repair strand breaks in DNA. All of these methods determine the extent of breakage of DNA and the resealing of these breaks but do not provide information on restoration of DNA configuration in the nucleus. In this report we have used a sensitive technique to investigate restoration of the 3-dimensional structure of DNA in AT lymphoblastoid cells after exposure to ionizing radiation. This technique provides a means of lysing cells using a high concentration of salt and a non-ionic detergent, giving rise to structures called nucleoids which contain nuclear RNA and DNA, are depleted in protein, and sediment in a manner characteristic of supercoiled DNA. We have shown that the degree of supercoiling is the same in control and AT lymphoblastoid cells using sedimentation in the presence of ethidium bromide. The extent of breakage after exposure of cells to gamma-radiation, and the rate of repair of these breaks are similar in both cell types. Rate of repair of strand breaks is dose dependent and the restructured rapidly sedimenting complex behaves similarly, on sucrose gradients containing ethidium bromide, to that extracted from unirradiated cells.

Ataxia Telangiectasia↗
PubMed1980

Renal osteodystrophy: an underdiagnosed condition.

With the availability of 1-alpha-hydroxycholecalciferol it is even more relevant to detect the earliest stages of renal osteodystrophy. Sixty-two patients, either on haemodialysis or recent recipients of a renal transplant and 10 controls underwent hand radiography by a standard technique and by a direct magnification technique employing a 0.1 mm focal spot. A comparison of intracortical striations, subperiosteal resorption and soft tissue calcification was made in the two groups and hand score calculated on the non-magnification radiographs. The results were assessed independently by two radiologists. In subperiosteal resorption, the non-magnification technique gave a 6% positive result compared to 47% with magnification (P less than 0.01). For intracortical striations, the non-magnification technique gave an 11% positive results, whereas magnification resulted in a 45% positive result (P less than 0.01). Soft tissue calcification was found in one patient only, and reduction in hand score was a rare occurrence. The use of a standard technique only, without magnification, for radiographing hands in patients with renal disease, will result in evidence of renal osteodystrophy being missed in a significant proportion of patients.

Adolescent↗
PubMed1980

Needle aspiration of the lung in complex pneumonias.

In 39 patients with treated unresponsive pneumonia complicated by life-threatening underlying disease, direct needle aspiration of the lung was performed to establish a cause. An infectious agent was detected in 18 patients (46 percent), a nonbacterial cause was found in one, and cure of a recent infection was substantiated in six patients. An incorrect diagnosis was made in seven patients (one false-positive and six false-negative), and an indeterminant answer was obtained by needle aspiration in seven. Serious complications occurred in 11 patients, most commonly in those who had hypoxia or thrombocytopenia, but no morbidity occurred in 22 patients. The diagnostic yield allowed effective rational therapy to be selected for multiple potential pathogens in 12 patients and detected pathogens not suspected in six instances. The technique compares favorably to other invasive techniques for establishing definitive information in this group of seriously ill patients.

Adult↗
PubMed1980

Bile acid excretion and patterns of fatty acid absorption in formula-fed premature infants.

Balance studies of individual fatty acid (FA) absorption and bile acid (BA) excretion were performed in 23 healthy premature infants fed proprietary formulas, utilizing gas-liquid chromatography. There was a direct correlation between the amount of BA excreted and absorption. This correlation was valid for total fat and for unsaturated dietary FA. Malabsorption of saturated FAs was in proportion to their hydrocarbon chain length and is best explained by their aqueous solubility, independent of BA. Assays of total FA absorption by gas-liquid chromatography and by the method of van de Kamer appear to be interchangeable.

Animals↗
PubMed1979

Fertility of dairy heifers given a commercial diet free of beta-carotene.

1. Dairy heifers given concentrates including vitamin A and wheat straw from 7 to 17 months of age had an average plasma beta-carotene concentration of 20--60 micrograms/l. Control heifers given the same diet but supplemented with beta-carotene had a beta-carotene plasma concentration of 630--2190 micrograms/l. 2. In contrast to previous findings no differences in duration of standing oestrus, length of oestrous cycle, plasma progesterone and luteinizing hormone (LH) concentrations and interval between LH peak and ovulation were observed between the groups. All the heifers conceived after one or two inseminations; conception rate being 69% for heifers given a diet free of beta-carotene and 78% for the controls. 3. Average rate of growth of heifers not supplemented with beta-carotene was 0.75+/-0.02 kg/d v. 0.81+/-0.02 kg/d for the controls (P less than or equal to 0.02). 4. The possible reasons for the discrepancy between present and previous findings are discussed.

Animals↗
PubMed1978

A clinical trial of mebendazole in the treatment of alveolar hydatid disease.

In July 1974, mebendazole was reported to be effective against the larval stage of Echinococcus granulosus in experimentally infected mice. A clinical trial of mebendazole was initiated in December 1974 in 4 patients with far advanced, nonresectable lesions caused by Echinococcus multilocularis. A daily dose of 40 mg of the drug per kg of body weight was administered to the 4 patients for more than 3 years. No evidence of toxicity or adverse reactions has been observed. Detectable plasma mebendazole concentrations were achieved with high-dose mebendazole therapy. Serum concentrations of IgE increased and decreased early in therapy. There was no evidence that the larval cestode was killed. The metastatic lesions appeared to be stabilized or diminished, and over-all clinical results were encouraging. Progressively enlarging thoracic metastases in 2 patients regressed during therapy, and symptomatic improvement was observed in all 4 patients. Mebendazole, a highly effective antihelmintic in enteric infections, is poorly absorbed by the gastrointestinal tract. Resulting low serum concentrations limit treatment of the massive, scirrhous lesions characteristic of E. multilocularis infections. Nevertheless, encouraging clinical responses observed with mebendazole therapy suggest that a more soluble form of this or a related drug might prove highly effective in the medical management of hydatid disease in humans.

Administration, Oral↗