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N S Radin

Publications and source records attributed to N S Radin.

At least 73 records · Page 4Linked to original sources
PubMed1985

Quantitation of thin-layer chromatograms with an Apple II computer-based videodensitometer.

An inexpensive, high-speed densitometer made from an Apple II computer, a black-and-white video camera, and an image digitizing board is described. By supplementing the computer with a very fast coprocessor, one can obtain a measurement of a typical thin-layer spot in 30-40 s. Only minimal electronic expertise is required for assembling the system from the commercially available components. Coefficients of variation for multiple readings of a single 500-ng spot of charred lipid were about 0.5%. For lipid spots weighing 250 to 2000 ng, a second-order relationship between weight and density reading was obtained with a correlation coefficient of 0.998.

Chromatography, Thin Layer↗
PubMed1985

Formation of free fatty acid and ceramide during brain handling: lability of sphingomyelin.

Intact brain and brain homogenates readily form free fatty acids and ceramides, even in the cold during subcellular isolation procedures. The fatty acid formation is slightly stimulated by chelators and might be due to phospholipid hydrolysis by lysosomal phospholipases. The ceramide formation is accompanied by loss of sphingomyelin and is apparently due to the action of neutral, metal ion-activated sphingomyelinase. The latter reaction is inhibited by EDTA whereas both degradative processes are inhibited by mercuriphenylsulfonate, the thiol-reacting inhibitor. Cerebroside does not seem to be a source of accumulated ceramide.

4-Chloromercuribenzenesulfonate↗
PubMed1984

Determination of the glucosidase-stimulating proteins by competitive enzyme-linked immunoassay.

A procedure for the immunoassay of cohydrolase sphingolipid-I in mouse tissue is described. This cohydrolase (actually a mixture of at least four related proteins) stimulates or activates the beta-glucosidase which hydrolyzes ceramide glucoside, a widely occurring glycosphingolipid. The method involves extraction of cohydrolase from tissue homogenate with a salt-buffer solution, removal of proteins by adjustment to pH 6, further removal of proteins by heating, and removal of interfering materials with a small size exclusion column. Antibodies were raised to bovine cohydrolase in rabbits and purified with an affinity column made from cohydrolase. The immunoassay involves binding of antibody by the cohydrolase sample (20-200 pg) in competition with cohydrolase that has been chemically linked to horseradish peroxidase. The mixture is treated with particle-linked second antibody and centrifuged; the pellet is then assayed fluorometrically for peroxidase content. Initial application of the method showed that cohydrolase was present in all mouse tissues studied and that its concentration paralleled that of glucocerebrosidase relatively closely. Changes with age (14 and 92 days) occurred in a similar fashion for the two substances.

Aging↗
PubMed1984

Effect of intravenous eicosapentaenoic acid on cerebral blood flow, edema and brain prostaglandins in ischemic gerbils.

Eicosapentaenoic acid is converted by cyclo-oxygenase to the prostacyclin, PGI3. Consequently eicosapentaenoic acid might protect the brain from the impairment in cerebral blood flow that follows temporary cerebral arterial occlusion. We studied the effect of 90% pure eicosapentaenoic acid, given intravenously, on cerebral blood flow, brain water and prostaglandins after ischemia in gerbils. Ischemia was produced by bilateral carotid occlusion for 15 min followed by reperfusion for 2 h. In experimental gerbils, 0.833 mg or 0.167 mg of eicosapentaenoic acid (Na salt) was given intravenously followed by a continuous infusion of 1 mg h-1. Control gerbils were given 0.167 mg of linoleic acid (Na salt) intravenously followed by a continuous infusion of 1 mg h-1 or a saline infusion. Regional cerebral blood flow was measured by the hydrogen clearance method and brain water by the specific gravity technique. Brain diene prostaglandins were measured by radioimmunoassay. In control gerbils cerebral blood flow decreased significantly during reperfusion and remained depressed after 2 h of reperfusion. In eicosapentaenoic acid treated gerbils blood flow decreased initially but after 2 h of reperfusion blood flow was significantly higher than in control gerbils. Brain edema and brain diene prostaglandins were not significantly different between control and experimental groups. Our study indicates that eicosapentaenoic acid, given intravenously, improves cerebral blood flow after ischemia and reperfusion. We speculate that this effect may be due to the formation of the prostacyclin, PGI3.

Animals↗
PubMed1984

Sodium 5-(3'-pyridinylmethyl)benzofuran-2-carboxylate (U-63557A) potentiates protective effect of intravenous eicosapentaenoic acid on impaired CBF in ischemic gerbils.

Eicosapentaenoic acid (EPA) has been reported to improve postischemic cerebral blood flow (CBF). The present study was designed to determine whether sodium 5-(3'-pyridinylmethyl)benzofuran-2-carboxylate (U-63557A), a selective thromboxane synthetase inhibitor, could potentiate the effects of EPA on CBF in ischemic gerbils. Ischemia was produced by bilateral carotid artery occlusion for 15 minutes followed by reperfusion for 2 hours. Immediately after ischemia, gerbils were given either an intravenous bolus of 0.167 mg of EPA followed by a continuous infusion of EPA at 1 mg/hr, or U-63557A (10 mg/kg intraperitoneally), or U-63557A and EPA, or a saline infusion. Regional CBF was measured by the hydrogen clearance method, and brain water by the specific gravity technique. Brain prostaglandins were measured by radioimmunoassay. Preischemic CBF's ranged from 27.4 to 29.5 ml/100 gm/min for the four animal groups. After ischemia and 2 hours of reperfusion, CBF in the saline-infused gerbils was significantly decreased to 19.2 ml/100 gm/min. Gerbils treated with either EPA or U-63557A alone had a CBF of 23.7 and 21.6 ml/100 gm/min, respectively. Postischemic CBF in animals treated with both U-63557A and EPA was 30.0 ml/100 gm/min, significantly higher than in saline-infused gerbils. Brain levels of 6-keto prostaglandin (PG)F1 alpha (the metabolite of PGI2) were significantly higher in gerbils treated with U-63557A and EPA compared to gerbils given EPA alone. This study indicates that U-63557A potentiates the effects of EPA on postischemic CBF. This is probably due to the ability of U-63557A to increase prostacyclin formation in the vessel wall.

Animals↗
PubMed1984

Improved version of the Kean partition assay for cerebroside sulfate.

In the Kean method for the colorimetric determination of sulfatide (1968. J. Lipid Res. 9: 319-327), the lipid is partitioned together with a blue cationic compound between two phases formed from chloroform, methanol, and water. The blue cation enters the chloroform-rich phase only as an ion pair with the lipid. This method has been improved by the use of a new mixture of solvents in which the desired layer floats above the excess dye. The lower volatility of the new solvent system improves the reproducibility of the technique.

Brain Chemistry↗
PubMed1983

The cohydrolases in human spleen that stimulate glucosyl ceramide beta-glucosidase.

A family of beta-glucosidase-stimulating proteins (called cohydrolase SPH-I here) was isolated from bovine, Gaucher human and control human spleens. All preparations exhibited a similar pattern of four major electrophoretic bands in polyacrylamide when stained with the cationic dye, Stains-All. The bovine bands migrated more rapidly, while the two types of human cohydrolase migrated very similarly. The two human preparations differed in several respects: the concentration was much higher in Gaucher spleen; the Gaucher factors eluted a little earlier from gel permeation and decyl agarose columns; much more of the cohydrolase was bound by a concanavalin A column; the control bands stained less intensely in gels than the Gaucher bands. Antibodies raised in rabbits to bovine cohydrolase reacted with all three preparations. All four bands from Gaucher cohydrolase showed similar ability to stimulate glucosidase and to bind the antibodies. It is evident that the cohydrolases from control and Gaucher spleens are similar in many respects, yet differ in some secondary fashion, possibly in carbohydrate content. It is suggested that Gaucher cohydrolase is formed from normal cohydrolase by the nonenzymatic action of cellular glucose over a period of many years, due to slowed catabolism of the cofactor.

Animals↗
PubMed1983

Free fatty acids in an animal model of Reye's syndrome.

Recent studies have indicated that viral infections, aspirin treatment and hyperammonemia are associated with Reye's syndrome. It has also been reported that free fatty acids in serum and total lipids in the liver of Reye's syndrome patients are elevated during illness. The role of the lipid changes in the development of the disorder cannot be optimally studied in human patients, because infection and aspirin ingestion occur prior to the earliest symptoms of Reye's syndrome. Effects of influenza B infection, aspirin treatment and hyperammonemia on the level of free fatty acids, total lipids and triacylglycerols in serum and liver of an animal model of Reye's syndrome are reported here. Hyperammonemia was produced in young, male ferrets either by feeding them small amounts of an arginine-deficient diet after overnight fasting or by an intraperitoneal injection of jackbean urease. The ferret model resembled Reye's syndrome in developing increased levels of individual and total serum free fatty acids, liver triacylglycerol and total lipids. The results also indicate that influenza infection or aspirin treatment, or both, while increasing the severity of encephalopathy in the deficient ferrets, did not cause a significant change in the level of serum free fatty acids. Other results suggest that elevation of serum ammonia, serum free fatty acid or liver lipids, either singly or in various combinations, does not provide conditions that can explain the rapidly developing encephalopathy in the arginine-deficient ferrets.

Ammonia↗
PubMed1983

An inexpensive, microcomputer-based, video densitometer for quantitating thin-layer chromatographic spots.

An inexpensive video densitometer based on an Apple II microcomputer using commercially available components was developed. The device was used to quantitate charred lipid and colored spots on thin-layer chromatography plates. The method is useful for lipid samples weighing 0.1 to 4 micrograms on high-performance plates and 1 to 20 micrograms on ordinary plates. The software automatically corrects for baseline drift due to dirt or nonuniformity in the plate.

Ceramides↗
PubMed1982

Determination of glucocerebroside, sphingomyelin, free fatty acid and total lipid by thin-layer chromatography and charring-scintillation quenching.

A previously described method has been extended to various specific lipids of liver and brain. The basic method involves thin-layer chromatography followed by charring to reveal the bands. The intensity of each band is determined by suspending the silica gel in a radioactive scintillation gel and measuring the optically quenched activities. The lipids are extracted with hexane/isopropanol and, in the case of total lipid determinations, the extract is simply applied to a silica gel plate and charred without use of a development step. For brain cerebroside, the extract is applied to the plate and developed in the usual way. For liver cerebroside, the dried lipid extract is fractionated with a silica gel column to purify the glycolipid, which is then purified further by development with a plate. For sphingomyelin the ester type lipids in the extract are cleaved by alkali for 1 min and the resultant lipids are applied directly to the thin-layer plate. Free fatty acids are chromatographed and measured after a preliminary solvent partitioning to remove most lipids. The method is useful for samples of 5-40 micrograms. Methods for quantitative application of samples to plates are described. A modification of the Camag sample streaker is described which yields precise 1-cm streaks.

Animals↗
PubMed1982

Brain glucocerebrosidase in Gaucher's disease.

Using glucocerebroside labeled with carbon 14 as the substrate, we determined that homogenates of brain tissue from both neuropathic and nonneuropathic cases of Gaucher's disease were profoundly deficient (more than 85%) in glucocerebrosidase activity. The beta-glucosidase activity, as measured with 4-methylumbelliferyl-beta-D-glucopyranoside as the substrate, in the homogenates of brain from four cases of Gaucher's disease was less sensitive to inhibition by conduritol B epoxide (CBE) when compared with normal brain beta-glucosidase. However, when homogenates were assayed with radiolabeled glucocerebroside as the substrate, no differential sensitivity toward CBE was indicated, suggesting the presence of an additional, CBE-insensitive, beta-glucosidase in brain tissue. Residual glucocerebrosidase activity partially purified from the brain of an adult with type 1 Gaucher's disease was activated threefold by gluconoyl hydrazine, whereas the same enzyme from control brain was unaffected, and eight times less sensitive to gluconolactone inhibition.

Adult↗