Search PubMed⌕ Search

Biomedical subjects

D F Smith

Publications and source records attributed to D F Smith.

At least 397 records · Page 22Linked to original sources
PubMed1975

Renal lithium, sodium, potassium and water excretion and plasma renin activity in rats in the cold.

A rise in urine volume and in the urinary excretion of lithium and sodium but not of potassium was observed in rats exposed to a cold environmental temperature (4 degrees C) for 3 hours. The level of plasma renin activity after the clerance test was correlated to the urine volume, but not to the electrolyte composition in the urine. The observed changes in the renal elimination of electrolytes and water corresponded to the effect that a cold environmental temperature has on kidney function in man. The results suggest that renal lithium clearance might be elevated in humans during exposure to cold.

Animals↗
PubMed1975

Detection of mild factor VIII Deficiency by thrombokinetics.

The maximal rate of change in optical density (Vmax-deltaOD)of plasma clots forming in the activated partial thromboplastin time test (APTT) may be significantly influenced by reductions in factor VIII activity insufficient to also cause a distinctly abnormal timed clotting endpoint. Analysis of relationships between Vmax-deltaOD of clotting plasma in the APTT, prothrombin time, and thrombin time tests provides a basis for increasing the screening value of the APTT in suggesting intrinsic system abnormalities. Three illustrative case reports support the added benefit of thrombokinetics in the detection of mild factor VIII deficiency in hemophilia A and in von Willebrand's disease.

Adult↗
PubMed1975

Growth and carcass evaluation of Holstein steers fed liquid acid whey.

Thirty Holstein steer calves, 96.5 kg, were assigned to three groups. Two groups received liquid acid whey, and one was the water control. Grain was fed either restricted or ad libitum to the whey groups and ad libitum to the water control group over three 14-wk growth periods. Hay, up to .4% body weight, reduced symptoms of bloat. Period 1: Calves started on a 20% crude protein dry ration for 7 wk and then changed to a 16% crude protein dry ration for 7 wk gained faster and were heavier than calves statred on a 30% crude protein dry ration for 7 wk and then changed to a 20% crude protein dry ration for 7 wk. Period 2: Body weights among groups were not different by the end of the period. Intakes of whey were 33.6 kg daily with grain ad libitum and 49.7 kg daily with restricted grain feeding. Water intake was 22.2 kg daily. The steers obtained 28% of their total dry matter intake from acid whey under ad libitum feeding, and 48% from acid whey under restricted feeding. Period 3: Final body weights were decreased by restricted feeding, but acid whey intake increased to 55.6 kg daily. These steers obtained 57% of their total dry matter intake from acid whey. Acid whey treatment resulted in lower carcass dressing percent, rib fat cover, and loin eye area. Grades averaged Standard for acid whey, restricted grain feeding and Low Good for acid whey, ad libitum grain feeding. Lower panel scores were given for aroma and quantity of juice for restricted grain feeding. Acid whey treatment did not change tenderness, shear values, or overall carcass desirability.

Adipose Tissue↗
PubMed1975

Erythrocyte delta-aminolevulinic acid dehydrase changes in the preruminant calf.

Sixteen preruminant, male Holstein calves were tested for erythrocyte delta-aminolevulinic acid dehydrase activity, hemoglobin and erythrocyte count in blood samples taken weekly during the first 13 wk of life. delta-Aminolevulinic acid dehydrase showed a continual increase in activity beginning at wk 3 to a maximal activity at wk 9. Hemoglobin content was decreased by wk 5 and erythrocyte count was reduced by wk 6. delta-Aminolevulinic acid dehydrase enzyme activities increased with age corresponding to changes in hemoglobin and erythrocyte count during early postnatal development of the preruminant calf.

Age Factors↗
PubMed1974

Culture medium for enterobacteria.

A new minimal medium for enterobacteria has been developed. It supports growth of Escherichia coli and Salmonella typhimurium at rates comparable to those of any of the traditional media that have high phosphate concentrations, but each of the macronutrients (phosphate, sulfate, and nitrogen) is present at a sufficiently low level to permit isotopic labeling. Buffering capacity is provided by an organic dipolar ion, morpholinopropane sulfonate, which has a desirable pK (7.2) and no apparent inhibitory effect on growth. The medium has been developed with the objectives of (i) providing reproducibility of chemical composition, (ii) meeting the experimentally determined nutritional needs of the cell, (iii) avoiding an unnecessary excess of the major ionic species, (iv) facilitating the adjustment of the levels of individual ionic species, both for isotopic labeling and for nutritional studies, (v) supplying a complete array of micronutrients, (vi) setting a particular ion as the crop-limiting factor when the carbon and energy source is in excess, and (vii) providing maximal convenience in the manufacture and storage of the medium.

Ammonia↗