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Biomedical subjects

A Sharif

Publications and source records attributed to A Sharif.

At least 19 recordsLinked to original sources
PubMed1994

Involvement of M2 and non-M2 muscarinic receptors in hippocampal theta rhythm induced by carbachol infusion into the septum of the rat.

Binding and autoradiographic studies have shown the presence of a rather high density of M2 muscarinic subtype receptors and the apparent absence or low density of the M1 subtype in the septum. We tested the hypothesis that, in the urethane-anesthetized rat, septal M2 receptors are involved in the generation of the hippocampal theta (theta) rhythm induced by intraseptal administration of carbachol, a potent cholinomimetic agent. Carbachol-induced theta was blocked by local infusion of the unspecific muscarinic antagonist agent, atropine (20 micrograms (29.55 nM)), given 10 min prior to carbachol. The intraseptal administration of low to high doses of gallamine (range: 20-180 micrograms (22.43-201.90 nM)), a specific M2 antagonist which displays high affinity for the septal region, resulted in significant changes in the electrophysiological characteristics of carbachol-induced theta but failed to abolish this rhythm. It is suggested that the latter may have resulted from a combined activation of both M2 and non-M2 receptors at septal level.

Animals↗
PubMed1994

Ribosomal protein S2/Sa kinase purified from HeLa cells infected with vaccinia virus corresponds to the B1R protein kinase and phosphorylates in vitro the viral ssDNA-binding protein.

A ribosomal protein S2 kinase was purified 6000-fold from cytoplasmic extracts of HeLa cells infected with vaccinia virus, using 80S ribosomes or 40S ribosomal subunits as a substrate. Although the preparation was not homogeneous, a 34K component was identified, the chromatographic behaviour of which correlated with enzyme activity. During its purification the ribosomal protein S2 kinase was resolved from a less abundant ribosomal protein S13 kinase, demonstrating the two to be different entities. A second protein kinase activity against a 43K ribosomal protein comigrated with the ribosomal protein S2 kinase activity during all five chromatographic procedures employed, and we conclude that the two activities are properties of a single species. Two-dimensional gel electrophoresis demonstrated that this second substrate was the acidic ribosomal protein Sa, of isoelectric point approximately 5.2, previously shown to be phosphorylated during infection with vaccinia virus. Another substrate for the ribosomal protein S2/Sa kinase in vitro was the 36K viral ssDNA-binding protein, of isoelectric point approximately 5.0, which is also known to be phosphorylated in vivo. The 34K protein correlating with the catalytic activity in the most purified preparations of the ribosomal protein S2/Sa kinase was recognized by an antibody specific for a protein expressed in Escherichia coli from vaccinia virus gene B1R. This and other evidence suggest strongly that the ribosomal protein S2/Sa kinase is the product of this gene.

DNA, Single-Stranded↗
PubMed1993

Identification of the leprosy bacillus and related mycobacteria by analysis of mycocerosate profiles.

Members of the phthiocerol dimycocerosate family of waxes were extracted from Mycobacterium bovis BCG, Mycobacterium tuberculosis, Mycobacterium kansasii, Mycobacterium marinum, Mycobacterium ulcerans and a skin biopsy from a leprosy patient. The waxes were degraded by alkaline hydrolysis and the mycocerosic acids converted to pentafluorobenzyl ester. Profiles of the esters, recorded using electron-capture gas-chromatography, gave characteristic profiles for the mycocerosates from M. leprae but those from M. bovis, M. tuberculosis and M. kansasii were superficially similar. The mycocerosate profiles from M. marinum and M. ulcerans were similar, but distinct from the others. Selected ion monitoring negative ion-chemical ionisation gas chromatography-mass spectrometry of of the pentafluorobenzyl esters allowed the analysis of mycocerosate isomers not revealed on gas chromatography alone. M. bovis and M. tuberculosis had similar profiles of C29, C30 and C32 mycocerosates; and additional C33 component was also present in M. kansasii. The mycocerosates from M. marinum and M. ulcerans were C27, C29 and C30 and those from M. leprae were distinct in having C29, C30, C32, C33 and C34 components. These methods have excellent potential for use in the detection of mycobacterial disease by direct analysis of infected tissue without prior cultivation of the causative agent.

Chromatography, Gas↗
PubMed1991

[Listeria monocytogenes contamination of raw milk from different regions of Anatolia and pasteurized milk sold in Ankara].

In this study 77 raw milk samples from different regions of Anatolia and 22 pasteurized milk samples sold in Ankara were investigated for isolation of L. monocytogenes. For the isolation of Listeria, each sample was plated directly onto McBride's Listeria Agar (MLA) and on the other hand four processing methods (2 long cold enrichment and 2 shortened warm enrichment procedures, followed by plating) were used. Listeria colonies on MLA medium were examined by the Henry Method of oblique lighting. Suspected colonies from MLA were subjected to biochemical tests to confirm identity. 14 samples (18.2%) of all examined samples raw milk were determined to be positive for Listeria monocytogenes. We found that Tryptose Phosphate Broth enrichment procedure gave significantly better results than others and allows L. monocytogenes isolation from milk most frequently. All of tested pasteurized milk samples were negative for L. monocytogenes.

Animals↗
PubMed1990

Characteristic new members of the phthiocerol and phenolphthiocerol families from Mycobacterium ulcerans.

Diacyl phthiodiolone A and phenolphthiodiolone A lipids were isolated from two strains of Mycobacterium ulcerans. The diol units of the phthiodiolone A and phenolphthiodiolone A components were shown to have erythro stereochemistry by infrared spectroscopy and proton nuclear magnetic resonance of an acetal derivative. This stereochemistry is shared only by related diols from M. marinum, the diols from M. bovis, M. kansasii, M. leprae and M. tuberculosis having threo stereochemistry.

Fatty Alcohols↗
PubMed1990

Screening for brucellosis in pregnant women.

During a period of 6 months, 537 pregnant women from a rural area in Saudi Arabia were tested serologically for brucellosis. Of the 513 women who were tested routinely, 18 were found to have a positive titre (3.5%). Of 24 patients in whom the test was carried out because of symptoms suggestive of brucellosis, all were positive. Thirty of the 42 positive cases had titres exceeding 1:160. The incidence of abortion among pregnant women with Brucella titres less than 1:160 was 7.7% contrasting with 17.6% among those with titres above 1:160 (P less than 0.04). This observation calls for further study of the incidence of brucellosis in pregnant women in infected areas, and the connection between elevated Brucella titre and abortion.

Abortion, Spontaneous↗
PubMed1988

In vitro study of the modification by bleomycin of thymidine phosphorylation activity in lectin-stimulated normal human lymphocytes.

We have investigated the effect of bleomycin (BLM) on thymidine phosphorylation in lectin-stimulated normal human lymphocytes. BLM reduces thymidine phosphorylation by decreasing the activity of thymidine kinase (TK). Accordingly, polyacrylamide gel electrophoresis (PAGE) of extracts of cells incubated for 48, 72 and 96 h showed here that this activity dropped 48, 65 and 67% respectively. The electrophoretic profiles of TK activity were similar but different in amplitude. These effects of the BLM were confirmed firstly by direct measurement of TK activity, secondly by amount of 3H-thymidine incorporation in the cultures before cell lysis. Both the measurement of TK activity and 3H-thymidine incorporation were correlated.

Bleomycin↗
PubMed1987

Calmodulin in lymphocyte mitogenic stimulation and in lymphoid cell line growth.

Calmodulin levels are elevated three- to fourfold in the dividing cells, resulting from the lectin-induced stimulation of fresh human lymphocytes. This increase in calmodulin appears to be related mainly to progression into S phase and supports the hypothesis that calmodulin might be crucial in regulating the progression of lymphoblasts through their division cycle. Calmodulin levels are higher in a lymphoid cell line derived from human acute lymphoblastic leukemia blood cells than in a lymphoid cell line derived from normal human blood cells, suggesting that calmodulin could be an important mediator of the leukemogenetic process.

Calmodulin↗
PubMed1985

In vitro study of the comparative behaviour of a human acute lymphoblastic leukemia cell line and a reference normal cell line towards the effects of a mitogenic lectin.

An in vitro study of the behaviour of a human acute lymphoblastoid leukemia cell line (REH) towards the action of a mitogenic lectin of Robinia pseudoacacia was carried out. The results were compared with those a reference cell line (LHN13) established from normal human lymphocytes. In both cell lines, the lectin induces agglutination (measured by counting the number of aggregates as well as the number of cells in each aggregate) and decrease of growth (measured by counting the number of cells and the incorporation of tritiated thymidine into TCA-precipitable material per 10(6) cells). The agglutination and the decrease of growth are produced at the doses of 0.5 and 1 microgram/ml of culture medium and after 4 h of exposure of cells to the lectin, respectively. These effects increase progressively with higher doses of lectin and continues throughout the culture. However, the REH line is less sensitive than the LHN13 line to the effects of lectin. Both agglutination and growth decrease of REH as well as LHN13 cell lines by the lectin are reversible; this is confirmed by the fact that the monospecific anti-Robinia lectin serum suppresses these effects.

Agglutination↗
PubMed1983

A microquantitative method for investigating the interaction between labeled lectins and the surface membranes of human lymphocytes using a semi-automatic harvesting machine.

We describe a simple, rapid and economical method for the study of the interaction of labeled lectins and the surface membranes of human lymphocytes using a semi-automatic harvesting machine (Titertek Multiple Cell Harvester). The procedure requires both small numbers of cells and small amounts of lectin, moreover it reduces the number of experimental steps required.

Cell Membrane↗
PubMed1983

Decrease in human lymphocyte surface glycoconjugates in leukemia as demonstrated by lectin binding.

Qualitative variations in the glycoconjugates which make up the lectin receptor sites on the membranes of leukemic lymphocytes, compared with those of normal cells, have been studied by the use of three tritiated lectins: Robinia pseudoacacia lectin, Concanavalin A and Ricinus communis (var. Sanquineus) agglutinin (RCA 120). The binding specificity of these lectins has been demonstrated using specific determinants: alpha-methylmannoside and galactose for Concanavalin A and Ricinus communis agglutinin respectively. For the Robinia lectin this specificity was determined by saturation of the receptor sites with the unlabeled Robinia lectin before the addition of isotopically labeled Robinia lectin. The results show a decrease in the number of receptor sites on the leukemia cells, especially in chronic lymphoid leukemia, relative to that on normal cells. The apparent affinity constants of leukemic cells in all cases remain higher than those of normal cells.

Cell Membrane↗
PubMed1978

The pericranium flap operation. A new operation for the treatment of progressive infantile hydrocephalus. A preliminary report of 20 cases.

A new operation is described for the treatment of progressive infantile hydrocephalus. A pericranial flap with intact blood supply is introduced into the right lateral ventricle and fixed in place by suture to the dura or the skull. Twenty cases were subjected to the new operation with four deaths. The operation was successful in causing the arrest of the hydrocephalus and changing the mental state of early and mild cases.

Humans↗
PubMed1978

Modifications of lectin binding on human leukemic cells after neuraminidase treatment.

Cell surface modifications after vibrio cholerae neuraminidase treatment were investigated using three different tritiated lectins: Concanavalin A, Ricinus sanguineus agglutinin (R.S.A.) and Robinia pseudoacacia lectin. Lectin binding measurements were performed on untreated and enzyme treated cells. The cells used were from chronic and acute leukemic donors. After neuraminidase treatment, a significant increase in the number of receptor sites, from 1 to 3 times, was found in all cases tested and for all three lectins utilized with only one exception. The affinity constant was generally decreased after neuraminidase treatment. The increase in number lectin binding sites, indicating extensive modification of the cell surface, is completely consistant with the known importance of sialic acid in determining immunogenicity.

Binding Sites↗
PubMed1978

Activation of human B lymphocytes induced by Robinia pseudoacacia lectin in the presence of T cells.

Robinia pseudoacacia seed lectin is a potent human lymphocyte activator which is capable of activating pure T cells but not pure B lymphocytes. However, when B and T cells were cultured together, the thymidine incorporation was found to be higher than that expected from B- or T-cell cultures alone. Killing of T cells by anti-human-T-lymphocyte antigen (HTLA) serum and complement at the time of thymidine incorporation was found to be unable to suppress completely the thymidine uptake whereas treatment by anti-human-B-lymphocyte and monocyte antigen (HBLMA) serum reduced the response to some extent. Moreover, stimulated lymphoblasts were shown to bear B-cell markers (surface Ig and complement receptors) in about the same proportion as B lymphocytes present in the cultures. These results show that B cells proliferate in the presence of T cells and Robinia lectin. Finally, activation of B cells by Robinia lectin in the presence of T cells led to their maturation to plasma cells in the same way as PWM.

Antilymphocyte Serum↗