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S Hurwitz

Publications and source records attributed to S Hurwitz.

At least 235 records · Page 13Linked to original sources
PubMed1976

Site of bile acid absorption in the rat.

Bile acid absorption was measured in the small intestine of the rat using 91Y as a nonabsorbed reference substance. Some 50% of the secreted bile acids were absorbed in the proximal half of the small intestine. In situ incubations of ligated intestinal segments into which tauro(14C-carbonyl)cholic acid was introduced confirmed the considerable uptake of bile acids in the jejunum. The situ experiments indicated that serosal transport is the limiting stage of bile acid absorption in the jejunum but not in the ileum. Increasing bile acid concentrations in the in situ experiments did not affect the percentage disappearance of dose from the jejunum but reduced the percentage mucosal uptake in the ileum. It is concluded that, in the rat, the proximal small intestine is as important in the absorption of bile acids as the distal small intestine.

Animals↗
PubMed1976

Regulation of intestinal calcium absorption in the laying quail: independent of kidney vitamin D hydroxylation.

Two experiments were carried out with laying quail (Coturnix coturnix japonica) fed either cholecalciferol (40 mug/kg) or 1 alpha-hydroxycholecalciferol (8 mug/kg). Recovery following vitamin D depletion, as indicated by egg production and shell deposition, was faster in quail fed 1 alpha-hydroxycholecalciferol than in those fed cholecalciferol. Overall intestinal calcium absorption was higher in the 1 alpha-hydroxycholecalciferol-fed quail due to a higher absorption in the middle parts of the small intestine. This was associated with corresponding differences in the concentration of calcium binding protein. Intestinal calcium absorption was markedly higher during periods of shell formation than during periods of uterine inactivity in quail fed either cholecalciferol or 1 alpha-hydroxycholecalciferol. It is suggested, therefore, that the mechanism responsible for this difference is independent of vitamin D hydroxylation in the kidney.

Animals↗
PubMed1976

Preparation of viable isolated bovine parathyroid cells.

A method is described for the preparation of isolated bovine parathyroid cells. Fresh, minced bovine parathyroid tissue is incubated with 2 mg/ml collagenase and 50 mug/ml DNAse for 1 h at 37 C with periodic pipetting. Parthyroid cells are separated from contaminating fat cells and red cells by low speed centrifugation. The resulting cell preparation is indistinguishable from parathyroid cells in intact bovine glands by light and electron microscopy. Hormone release is linear for at least 3 h at both high (2.0 mM) and low (0.5 mM) calcium concentrations and is inversely proportional to divalent cation concentration between 0.3 mM and 1.0 mM calcium as been observed previously both in vivo and in vitro. As in previous studies, hormone release is also stimulated up to 2-fold by 10(6) M (-)isoproterenol, an effect blocked by 10(-6)M (-)propranolol, suggesting a beta-adrenergic effect. Such a cell preparation should be useful for studying hormone binding and effects on cyclic nudleotides and cellular transport phenomena in both normal amd abnormal tissue.

Animals↗
PubMed1976

Calcium-binding protein and calcium absorption in the laying quail (Coturnix coturnix japonica).

A vitamin D3-dependent calcium-binding protein (CaBP) has been found in the intestinal mucosa of Japanese quail (Coturnix coturnix japonica). This protein is similar, if not identical to that of the chick (Gallus domesticus). A similar protein fraction appears also in uterine mucosa of laying quail. Both intestinal and uterine CaBP levels are higher in laying than in non-laying quails. Uterine CaBP was higher during egg shell formation than during uterine inactivity. The slight corresponding difference in the intestinal CaBP was not significant. Intestinal calcium absorption measured with 91Y as a reference substance was higher in birds during formation of egg shell than in those with inactive uteri. The possible role of CaBP in calcium translocation is discussed.

Animals↗
PubMed1976

Acne vulgaris.

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Acne Vulgaris↗
PubMed1975

Response of renal calcium-binding protein. Independence of kidney vitamin D hydroxylation.

Dietary calcium and dietary phosphorus restriction were studied in chicks fed either cholecalciferol or 1alpha-hydroxycholecalciferol. Intestinal calcium absorption and calcium-binding protein of 1alpha-hydroxycholecalciferol-treated chicks remained unchanged under dietary calcium restriction, but increased under dietary phosphorus restriction. Kidney calcium-binding protein was not altered by dietary caclium restriction in chidks treated with either cholecalciferol or 1alpha-hydroxycholecalciferol, but increased under dietary phosphorus restriction independent of the vitamin D source. In contrast to the intestine, calcium-binding activity of the kidney was found to be poorly related to the calcium-binding protein concentration. It is suggested that kidney calcium-binding protein is regulated by a mechanism different from that of intestinal calcium-binding protein, and that its concentration in renal tissue is related to renal caclium excretion or plasma calcium level.

Animals↗
PubMed1975

The functional metabolism of vitamin D in chicks fed low-calcium and low-phosphorus diets.

Radioactively labelled cholecalciferol was administered continuously to chicks that were fed normal, low-calcium and low-phosphorus diets. It has been possible to show that under such steady state conditions with regard to cholecalciferol, and mineral restriction, the animal reacts by increased accumulation of 1, 25-dihydroxycholecalciferol in the intestinal and the kidney cell, which was associated in the intestine with an increased calcium-binding activity. A similar accumulation of 1, 25-dihydroxycholecalciferol in bone was not noticed. It is proposed that the intestine and the kidney, but not bone, are the main target organs for cholecalciferol in the maintenance of calcium homeostasis, and that both calcium and phosphorus play a role in the regulation of the formation and subsequent function of 1, 25-dihydroxycholecalciferol.

Animals↗
PubMed1975

51Cr-EDTA, 91Y and 141Ce as nonabsorbed reference substances in the gastrointestinal tract of the chicken.

The use of 91Y, 51Cr-EDTA, and 141Cr as nonabosrbed reference substances in the gastrointestinal tract of the chick was examined. In single oral dose experiments, more than 95% of the isotopes administered was recovered from the gastrointestinal tract 3 hours after dosing. 51Cr was higher in blood than the other isotopes tested. When the isotopes were fed continuously, the ratio of 91Y to 141Cr changed little throughout the gastrointestinal tract. However, the ratio of 91Y to 51Cr was higher in the crop and gizzard and lower in the duodenum than in the feed. Thus, passage time was shorter for 51Cr in the crop and gizzard and longer in the duodenum than that of 91Y. On the basis of distribution between solid and liquid phases in the intestinal contents, 91Y or 141Ce appears to be a suitable reference substance for studying the absorption of nitrogen and fatty acids, wheras 51Cr-EDTA would be preferable for bile acid absorption studies.

Animals↗
PubMed1975

Immunologic studies in patients with recurrent bronchopulmonary infections.

In view of the known association of several different immune deficiency disorders with infections of the respiratory tract, a number of immunologic parameters were investigated in 15 patients with recurrent brochopulmonary infections. The patients' neutrophils all demonstrated normal intracellular killing of Staphylococcus aureus, and responded normally to chemotactic stimuli. Although assays of complement 3c were normal in all patients' sera, defective total hemolytic complement activity was consistently shown in 1 patinets manifested elevated serum immunoglobulin concentrations. Severe alpha1 -antitrypsin deficiency (Pi ZZ phenotype) was discovered in 1 patient. Three patients displayed cutaneous anergy to a battery of skin-test antigens, but lymphocytes from all patients studied responded normally to in vitro phytohemagglutinin stimulation. A "blocking" factor found in the serum of 3 patients suppressed the in bitro transformation of normal Candida-responsive lymphocytes by Candida albicans antigen. "Cold" lymphocytotoxins were detected in the sera of 10 patients, but in only 3 of 19 control sera. Although the significance of these findings is unknown, they may possibly have pathogenetic relevance in a small number of the patients studied.

Adolescent↗
PubMed1975

Some responses of laying hens to induced arrest of egg production.

Arrest of egg production was induced by forced-molt (artificial light deprivation and feed deprivation for 10 days followed by 20 days of grain only) and by low-calcium regime in one experiment, and by Nicarbazin in another. Post-arrest production and shell quality significantly surpassed the control in the force-molt but not in the low-Ca treatment. At the onset of production, following the pause, egg weight and shell weight per unit of surface area rapidly increased up to the 9-10th egg. In the second trial, feed intake declined in about one week after the arrest in egg production to a non-layer level. During this week, body weight increased. However, despite the increase in feed intake after the onset of production, pre-arrest levels were not obtained even after 11 days, resulting in a loss of body weight. The separation of flock production into its components, rate of production of the layers, and the proportion of layers in the flock, is proposed.

Animal Feed↗
PubMed1975

Changes in oxygen delivery during hemodialysis.

The effect of hemodialysis on oxygen delivery has been assessed in nine patients. During hemodialysis the arterial PO2 decreased from 76.89 mm Hg to 69.03 mm Hg. There was also an increase in pH from 7.39 to 7.49 which resulted in an increase in the affinity of the blood for oxygen. In the absence of compensatory changes this could result in a 17.9% decrease in oxygen delivery. This could be hazardous in patients who are already anemic particularly in the presence of cardiac or respiratory insufficiency.

Adult↗