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Biomedical subjects

W Straus

Publications and source records attributed to W Straus.

34 records · Page 2Linked to original sources
PubMed1977

Altered renal cortical reabsorption of protein and urinary excretion of sodium in relation to vascular leakage induced by horseradish peroxidase.

The intravenous injection of horseradish peroxidase (HRP) into rats of the Sprague-Dawley strain caused vascular leakage as detectable by a 20-40% increase in the hematocrit and a 15-20% decrease in plasma protein concentration. These changes did not occur when the same amounts of HRP were injected into rats pretreated with antagonists to histamine and serotonin. After pretreatment with the antagonists, the reabsorption of HRP by the proximal tubule cells (the concentration of HRP in the total particulate fractions) showed a 77% decrease and the urinary excretion of sodium showed more than an 80% increase as compared to the values from rats treated with HRP alone. In addition, the blood clearance rate of HRP was decreased and the urinary excretion of HRP was increased after treatment with the antagonists to histamine and serotonin. Cytochemical observations of formaldehyde vapor-fixed tissue also showed the effects of vascular leakage. After the injection of HRP in physiologic or hypertonic saline, the basal infoldings of the proximal tubule cells were strongly peroxidase-positive. When the same amounts of HRP were injected after pretreatment with antagonists to histamine and serotonin, or with mannitol, the basal infoldings were not stained or were stained faintly. Rats of the Wistar/Furth strain did not show the effects of vascular leakage observed with rats of the Sprague-Dawley strains. The questions are discussed as to whether the marked depression of renal cortical HRP absorption by mannitol and hypertonic saline (J Histochem Cytochem 23:707, 1975) is related to the prevention of vascular leakage, and whether the reabsorption of both sodium and protein is increased during the leakage of serum proteins into the interstitial tissue.

Animals↗
PubMed1975

Altered reabsorption of protein by the renal cortex in rats treated with hypertonic saline or mannitol.

The reabsorption of horseradish peroxidase (HRP) by the proximal tubule cells of rat kidneys was investigated by measuring the concentration of HRP in total particulate fractions of the cortex 1/4 and 1 hr after intravenous injection, and by correlated cytochemical observations. When compared to the corresponding values of the control animals, the concentration of HRP 1 hr after injection was decreased approximately 10-fold in the renal cortex of rats which had received an intravenous injection of hypertonic saline or two subcutaneous injections of mannitol. The plasma clearance and the urinary excretion of HRP were not altered significantly after injection of hypertonic saline, but the plasma clearance was decreased and the urinary excretion increased after injection of mannitol. When the dose of injected HRP was varied, the reabsorption of HRP by the renal cortex was proportional to the dose in the experimental and the control animals. Cytochemical staining for peroxidase activity also showed that the phagosomes and phagolysosomes of the proximal tubule cells contained much less peroxidase in the experimental rats than in the control rats. After injection of mannitol, large vacuoles appeared in the proximal tubule cells. The vacuoles often contained peroxidase-positive granules (phagosomes) which varied in diameter from the limit of microscopic visibility up to several microns. Most of the vacuoles did not react for acid phosphatase activity, but lysosomes were often aggregated around the vacuoles and seemed to release acid phosphatase into the cytoplasm. Certain analogies between the reabsorption of protein and that of water by the proximal tubule cells are discussed.

Animals↗
PubMed1971

Comparative analysis of the concentration of injected horseradish peroxidase in cytoplasmic granules of the kidney cortex, in the blood, urine, and liver.

The concentration of horseradish peroxidase in total particulate fractions from the kidney cortex did not change much during the first few hours after injection, as long as most of the injected protein was not yet cleared from the blood. It decreased at a rate of 6-8% per hr afterwards. The concentration of peroxidase in total particulate fractions increased in proportion to the load (dose) over a wide range, suggesting that a constant fraction of the protein was reabsorbed by micropinocytic vesicles into the tubule cells from the glomerular filtrate. The amount of peroxidase excreted in the urine also increased in proportion to the injected dose. The proportion of peroxidase taken up by the liver, however, decreased several times when the dose was increased. A marked decrease of protein uptake into the kidney cortex and an increase of urinary excretion were observed when rats received a second, equal dose of peroxidase 4 hr after the first injection, and the rate of clearance of peroxidase from the blood was decreased after the second injection. The liver, on the other hand, took up almost twice as much peroxidase after two injections as after one. The uptake of peroxidase by the kidney cortex increased with age. Cytochemical observations on the preferential absorption of peroxidase by certain cell types and segments of the renal tubules in relation to dose are reported.

Absorption↗