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Biomedical subjects

M L Williams

Publications and source records attributed to M L Williams.

At least 253 records · Page 14Linked to original sources
PubMed1976

The influence of vitamin A on the susceptibility of the rat lung to 3-methylcholanthrene.

The susceptibility of rats to pulmonary carcinogens is increased in the absence of vitamin A intake even when considerable amounts (0.4 nmole/mg) of vitamin A are stored in the liver and deficiency symptoms are absent. This was demonstrated in studies on the induction of metaplastic lung nodules by intratracheally administered 3-methylcholanthrene. Only moderate amounts of all-trans-retinyl acetate in the diet (7.6 nmole/g of diet) were required to prevent the development of this state of enhanced susceptibility. A further increase in intake of retinoids (by intragastric administration of either all-trans-retinyl acetate or 13-cis-retinoic acid) provided no additional protection against the effects of carcinogen.

Animals↗
PubMed1976

The role of exchange transfusions in the management of low-birth-weight infants with and without severe respiratory distress syndrome. II. Further observations and studies of mechanisms of action.

Exchange transfusion, as a form of therapy, was contrasted with the use of fresh frozen plasma or conventional supportive care alone in the management of 19 infants with birth weights of less than 1,000 gm, without severe respiratory distress, and in the management of 82 infants, birth weights less than 2,000 gm, with severe respiratory distress whose disease manifested itself within the first 24 hours of life. Survival for more than five days was similar, regardless of therapy, in infants weighing less than 1,000 gm without severe RDS. In contrast, the use of exchange transfusion significantly decreased the case fatality rate of infants with severe RDS. In the groups receiving exchange transfusion, the mortality rate was 41%, whereas the groups receiving either plasma or supportive care alone the mortality was 80%. Study of coagulation factors and red cell concentrations of fetal hemoglobin and of 2,3-DPG failed to demonstrate any relationship between either improvement in coagulation or oxygen unloading and the improved survival of infants receiving exchange transfusion. Following exchange transfusion there was a significant decrease in the ratio of FIO2 to PaO2, suggesting that pulmonary perfusion and/or ventilation was improved by the procedure.

Acidosis, Respiratory↗
PubMed1975

Role of dietary iron and fat on vitamin E deficiency anemia of infancy.

Thirty-five infants weighing less than 1500 g at birth were fed four commercial formulas (A-D) varying in polyunsaturated fatty acid composition (32 per cent linoleic acid in A and B and 12 per cent linoleic acid in C and D) and in iron content (smaller than 1.0 in A and B; 12 to 12 mg per liter in B and D). Infants receiving formula B showed significantly lower hemoglobins (p smaller than 0.01) and higher reticulocyte counts (p smaller than 0.005) than infants fed the other three formulas. Infants receiving the two formulas with higher concentrations of unsaturated fatty acids (A and B) showed significantly greater hydrogen-peroxide-induced hemolysis (p smaller than 0.001) than those given diets containing lower amounts. Infants in groups A and B also had lower serum tocopherol concentrations. Infant red-cell membranes are altered by the increased amounts of polyunsaturated fatty acids and iron in the diet. It appears that the development of vitamin E deficiency anemia occurs in infants receiving iron supplementation.

Anemia, Hemolytic↗
PubMed1975

The effects of 5-fluorouracil and 5-fluorodeoxyuridine used alone and in combination with normal nucleic acid precursors on development of mice in lines selected for low and high expression of Strong's luxoid gene.

Pregnant female mice selected for plus- and minus-modifying genes of the limb-skeleton effects of Strong's luxoid gene (1st) were injected ip on day 10 of gestation with 10 or 20 mg/kg 5-fluorouracil (5-FU) or 5-fluorodeoxyuridine (5-FUdR). The incidence and degree of expression of the effects (polydactyly, ectrodactyly, radial hemimelia, tibial hemimelia, pelvic girdle shifts, deformed caudal vertebrae) varied according to the teratogen and dose level. The addition of an equimolecular amount of thymidine, thymine, or uracil greatly potentiated the effects of 20 mg/kg 5-FU, usually resulting in death of the embryos. The addition of an equimolecular amount of thymidine but not of the embryos. The addition of an equimolecular amount of thymidine but not of thymine or uracil partly protected against the effects of 5-FUdR. Both teratogens increased the expression of ist on the limb skeleton. The interactions of the teratogens with the major gene were inhibited by minus- and promoted by plus-modifying genes of 1st. The effects of the teratogenic treatments may be mediated by cell death.

Abnormalities, Drug-Induced↗
PubMed1975

Prophylaxis against hypocalcemia in low-birth-weight infants requiring bicarbonate infusion.

Forty-eight low-birth-weight infants with varying degrees of respiratory distress were studied with respect to serum calcium concentration and urinary calcium excretion. Serum calcium decreased over the 24-hour study period in infants who did not receive calcium infusion. The decrease was greater in those receiving bicarbonate therapy for acidosis. Continuous calcium infusion at 1 mg/kg/hr sustained relatively normal serum calcium concentration, even in those infants who required bicarbonate. Since the changes in estimated extracellular calcium could not be accounted for by urinary excretion, a shift of calcium into bone was postulated.

Bicarbonates↗