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Biomedical subjects

S Majumdar

Publications and source records attributed to S Majumdar.

At least 361 records · Page 20Linked to original sources
PubMed1982

Pregnancy specific proteins: suppression of in vitro blastogenic response to mitogen by these proteins.

Immunosuppressive properties of human chorionic gonadotropin (HCG), pregnancy specific B1-glycoprotein (SP-1), human alpha foetoprotein (AFP), and human placental lactogen (HPL) in mitogen-stimulated lymphocyte transformation were studied. A pregnancy serum containing high serum levels of these specific proteins was prepared from a number of pregnancy sera. The inhibitory effect of pregnancy sera on lymphocyte response to mitogen was examined after sequential removal of each of the proteins from the pregnancy serum by affinity chromatography. Greatest decrease in the suppression was observed when human chorionic gonadotropin (HCG) alone or human chorionic gonadotropin in combination with all other three specific proteins was removed from the pregnancy serum. Pregnancy specific B1-glycoprotein (SP-1) also significantly decreased the inhibitory effect of pregnancy serum. But the other two specific proteins (AFP and HPL) had minimal effect on the decrease an immunosuppression by pregnancy serum. However, even after removal of all the four pregnancy specific proteins from the pregnancy serum, complete return to normal values for lymphocyte transformation by mitogen was not observed, which indicates the presence of some other suppressive factor(s) in the pregnancy serum.

Animals↗
PubMed1982

Altered lipid profile, postheparin lipolytic activity, and xanthoma of choroid plexus in vasectomized rabbits fed an atherogenic diet.

Plasma and erthrocyte lipid profile and lipoprotein lipase activity in postheparin plasma on vasectomized rabbits were studied and also the incidence of atherosclerosis in different arterial beds. Four groups of animals were studied, sham-vasectomized and vasectomized animals fed stock diet (groups A1, A2) and sham-vasectomized and vasectomized animals fed atherogenic diet (groups B1, B2). Elevated levels of neutral lipids and phospholipids in plasma and in erythrocytes of the vasectomized rabbits were observed. This elevation of blood lipids was the result of an increase in all fractions, however, phosphatidylcholine increased more than other phospholipid fractions in plasma. In erythrocytes the increase of phosphatidylethanolamine was greater than that of phosphatidylcholine. The accumulation of triglyceride-rich plasma lipids in all the vasectomized rabbits may be the result of a relatively decreased stimulation of postheparin lipolytic activity. The vasectomized animals given atherogenic diet revealed a significantly greater aortic sudanophilia and extensive occluding coronary atherosclerosis as compared to lesions seen in sham-vasectomized rabbits fed the same diet. Two rabbits of group B2 had xanthomatous lesions in choroid plexus of brain.

Animals↗
PubMed1982

Effect of seminal plasma and its fractions on in vitro blastogenic response to mitogen.

Five fractions of human seminal plasma were isolated on Sephadex G-100 column. The in vitro effect of whole human seminal plasma and its fractions on the lymphocyte transformation induced by phytomitogen was studied. A significant inhibition of lymphocyte response to mitogen was observed with whole seminal plasma fractions I and III at a concentration of 100-200 micrograms/ml. However fraction II stimulates the in vitro human lymphocyte transformation induced by phytomitogen at a concentration of 200 micrograms/ml. Maximum amount of inhibition by whole seminal plasma and its fractions I and III was achieved by preexposure of lymphocytes to these antigens. Pre-exposure of lymphocytes to these antigens, followed by washing, does not result in suppression of lymphocyte response to mitogen. These observations suggest that the antigens of the whole seminal plasma or of fractions I, III, and II act by simple competition with mitogen for the receptor sites on the lymphocyte membrane. Therefore, the human seminal plasma may play an immunoregulatory role against the auto- or isosensitization towards spermatozoal antigens.

Cells, Cultured↗
PubMed1981

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.

Animals↗
PubMed1980

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.

Calcium↗
PubMed1980

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.

Adolescent↗
PubMed1977

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.

Animals↗