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Biomedical subjects

B D Stacy

Publications and source records attributed to B D Stacy.

34 records · Page 2Linked to original sources
PubMed1970

Acidosis and hypercalciuria: renal mechanisms affecting calcium, magnesium and sodium excretion in the sheep.

1. Observations were made on the excretion of calcium and magnesium by the sheep's kidney following manipulation of the acid-base status.2. Intravascular administration of a synthetic solution resembling saliva abolished the naturally occurring acidosis in sheep during feeding, and it also prevented the normal onset of post-prandial hypercalciuria and hypermagnesiuria.3. Non-respiratory acidosis (induced by infusion of hydrochloric acid) and respiratory acidosis arising from inhalation of 6% (v/v) CO(2) in air both caused an acute increase in calcium excretion.4. Measurement of filtered loads showed that feeding exerted an effect on the functional characteristics of the sheep's kidney. The renal clearances of calcium and magnesium increased, whereas sodium clearance decreased.5. Experimental conditions were arranged so that variations in acid-base status could be imposed at a time when the filtered load of calcium was declining.6. With hydrochloric acid-acidosis the renal excretion of calcium increased, despite a steady fall in the filtered load. With sodium bicarbonate alkalosis, the filtered load and the renal excretion of calcium decreased in unison.7. These variations in calcium excretion were not accompanied by corresponding changes in the excretion of sodium.8. It is concluded that the renal tubules in the sheep are sensitive to acid-base status and that they respond to a lowering of the blood pH by decreasing the tubular reabsorption of filtered calcium.

Acid-Base Equilibrium↗
PubMed1968

The function of antidiuretic hormone in the sheep.

1. With the aim of producing diabetes insipidus in sheep, electrolytic lesions were placed in the ventral medial hypothalamus immediately posterior to the optic chiasm.2. After formation of lesions, the pattern of urine excretion showed a triphasic response consisting of (i) an immediate diuresis reaching a maximum within 4 days, (ii) an interphase of about 12 days wherein rates of urine flow were normal, and (iii) a final phase of permanent polyuria. With the four sheep used in this work, the time between placement of the lesions and onset of permanent hyposthenuria was 19-22 days.3. In the final polyuric phase, the sheep were unable to concentrate their urine in response to dehydration or to feeding.4. Infusions of arginine vasopressin restored the ability of these animals to excrete urine that was hypertonic to plasma.5. The evidence showed that the hypothalamic lesions were effective in producing permanent diabetes insipidus. It was concluded that anti-diuretic hormone (ADH) has essentially the same function in sheep as it has in other mammalian species; that is, the hormone facilitates the elaboration of hypertonic urine. There was no evidence to suggest that ADH had a special effect on potassium excretion in the sheep.

Animals↗
PubMed1966

Chromium-51 ethylenediaminetetraacetate for estimation of globerular filtration rate.

Renal clearances of inulin and chromium-51 ethylenediaminetetraacetate were compared in sheep. In 41 clearance periods from five animals the mean clearance ratio of the chelate to inulin was 0.95 +/- 0.03 (S.D.). Part of the difference between the two sets of results may have been due to binding of the metal chelate by plasma protein since 1.5 to 2 percent of chromium-51 ethylenediaminetetraacetate in plasma could not be removed by dialysis.

Animals↗