Alterations in the activities of intestinal enzymes in vitamin-C-deficient guinea pigs

The effect of vitamin C deficiency on various enzymes of the intestinal epithelium has been studied in guinea pigs. Brush border sucrase and alkaline phosphatase activities were considerably enhanced (p less than 0.001), but leucine aminopeptidase levels were reduced in scorbutic animals compared to the control group. There was essentially no change in the activity of maltase under these conditions. Kinetic studies with sucrase and alkaline phosphatase in control and scorbutic animals revealed that augmentation of the enzyme activities in scurvy is due to enhanced enzyme contents. Lactate dehydrogenase, succinate dehydrogenase, glucose-6-phosphatase and Mg+2 ATPase also exhibited reduced activities in the intestine of vitamin-C-deficient animals. Observed alterations in the activities of intestinal enzymes in scurvy were restored to control levels upon feeding of vitamin C to scorbutic guinea pigs.

Effect of vitamin C deficiency in guinea pigs on intestinal functions and chemical composition of brush border membrane

The effect of vitamin C deficiency on the digestive and absorptive functions of the gut has been investigated in guinea pigs. The absorption of D-glucose was significantly elevated, but that of L-leucine, L-alanine and L-lysine considerably depressed in the intestine of scorbutic guinea pigs compared to controls. The intestinal transport of vitamin B12 was also diminished. Activities of sucrase and alkaline phosphatase on the brush border were enhanced, but that of leucine aminopeptidase markedly reduced in scorbutic animals compared to controls. Maltase activity was unaffected in vitamin C deficient animals. Chemical analysis of the brush borders isolated from scorbutic animals revealed a considerable decrease in membrane protein, total lipids, phospholipids, and free cholesterol contents compared to control animals. In vivo 2-(14)C-acetate incorporation into membrane lipids suggested that the observed decrease in lipid components of the scorbutic membranes is due to reduced synthesis. Administration of ascorbic acid to scorbutic animals ameliorated the intestinal aberrations observed in scurvy.

Fusion of human erythrocytes induced by uranyl acetate and rare earth metals

Incubation of human erythrocytes with either uranyl ions (UO22+) or rare earth metals (La3+, Nd3+, Sm3+, Eu3+, Tb3+, Dy3+ and Yb3+) at 37 degrees C for 30-45 min resulted in the fusion of erythrocytes. Redistribution of membrane-associated particles was observed using colloidal-iron charge labelling and freeze-fracture electron microscopy. The fusion of erythrocytes induced by these agents, unlike Ca2+, did not exhibit the absolute requirement for phosphate. Moreover, agglutination and fusion by these agents was observed in neuraminidase-treated erythrocytes in contrast to Ca2+- and phosphate-induced fusion. Inhibitors of intrinsic transglutaminase activity partially inhibited (35-45%) the fusion induced by UO22+ suggesting that cross-linking of membrane proteins results in protein-free areas of lipid where fusion may be initiated.

Sea-blue histiocytes in idiopathic thrombocytopenic purpura. The first report from the Indian subcontinent

Sea-blue histiocytes are described in the bone marrow of a 15-year-old male patient suffering from idiopathic thrombocytopenic purpura. Cytochemically the storage material in these cells appeared to be glycophospholipid. Lipid analysis of blood leucocytes and nucleated cells of bone marrow showed a significant increase in the phospholipids, triglycerides and cholesterol as compared to age-matched controls. Serum lipid analysis showed a mild increase of phospholipids as compared to age-matched controls.

Effect of phenylhydrazine on the plasma lipids of albino rat

The effect of phenylhydrazine hydrochloride on the lipid composition of plasma of albino rats have been investigated. The data revealed significant increase in the percentages of lysophosphatidyl choline and decrease in that of phosphatidyl choline. There was increase in the cholesterol ester content in the plasma. The assay of plasma lecithin-cholesterol acyltransferase (LCAT) activity showed a significant increase in its activity parallel to the above changes.

An unusual intranuclear structure (? viral nucleocapsid) in the brain in subacute sclerosing panencephalitis

A brain biopsy was examined from a 7 year old boy with subacute sclerosing panencephalitis. Intranuclear deposits of measles antigens were demonstrated in parenchymal cells by immunofluorescence. Electron microscopy showed viral nucleocapsids in nucleoliform inclusions and unusual rod-like intranuclear structures which resemble structures previously described only in tissue cultures infected with measles virus.