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Biomedical subjects

J Basu

Publications and source records attributed to J Basu.

At least 19 recordsLinked to original sources
PubMed1992

Fatty acylation of a 55 kDa membrane protein of human erythrocytes.

The major palmitoylated human erythrocyte membrane protein has an M(r) of 55,000. It is distinct from the glucose transporter and is not derived from band 3 or ankyrin. It resists salt extraction suggesting a high affinity for the membrane. Pulse chase experiments demonstrate that palmitoylation is a dynamic process, and it may therefore have regulatory significance in membrane protein-protein or protein-lipid interaction. Slower dynamics of palmitoylation in erythrocytes from patients suffering from chronic myelogenous leukemia, which are less stable than normal erythrocytes, strengthen this view.

Acylation↗
PubMed1992

Purification of a phosphatidylinositol/phosphatidylcholine transfer protein from Neurospora crassa.

This paper reports, for the first time, the purification of a phospholipid transfer protein (PLTP) from a fungus, Neurospora crassa. The protein was purified from the post-microsomal supernatant of N. crassa by successive chromatography on DEAE-cellulose, Sephadex-G75 and PBE 94 (pH 4-7). The purified protein (M(r) 38,000) was found to transfer phosphatidylinositol preferentially over phosphatidylcholine, like the PLTP from the yeast, Saccharomyces cerevisiae. PC transfer was completely inhibited by inactivation of free amino groups or tryptophan residues. Surprisingly, the protein did not cross-react with antibodies against the bovine brain PITP. The cellular content of the protein was maximal during the logarithmic phase of growth. However, no direct correlation between the content of the protein and PC transfer activity could be demonstrated.

Androgen-Binding Protein↗
PubMed1992

Beta-carotene levels in exfoliated cervicovaginal epithelial cells in cervical intraepithelial neoplasia and cervical cancer.

OBJECTIVE: The purpose of this study was to measure beta-carotene levels in exfoliated epithelial cervicovaginal cells collected by a lavage technique in normal women and patients with histopathologically diagnosed cervical intraepithelial neoplasia and cervical cancer. STUDY DESIGN: In a cross-sectional sampling of women (n = 105), cervicovaginal cells and plasma beta-carotene levels were assayed with high-pressure liquid chromatography. In addition, beta-carotene levels were measured in exfoliated epithelial samples of cervicovaginal cells obtained from women (n = 24) enrolled in an ongoing oral beta-carotene supplementation clinical trial. RESULTS: Cervicovaginal cells and plasma beta-carotene levels were found to be significantly decreased in women with cervical intraepithelial neoplasia and cervical cancer as compared with controls (p < 0.0001, analysis of variance). Retinol levels in cervicovaginal cells were undetectable. The beta-carotene levels in cervicovaginal cells were markedly increased in the majority of patients (79%) after oral supplementation as compared with baseline levels in women enrolled in the beta-carotene clinical trial. CONCLUSION: The study demonstrates that changes of in situ cellular beta-carotene concentrations are measurable in samples of exfoliated epithelial cells obtained by a noninvasive saline lavage harvesting technique. The current findings further support our previous hypothesis that beta-carotene deficiency may have an etiologic role in the pathogenesis of cervical intraepithelial neoplasia and/or cervical cancer.

Adolescent↗
PubMed1992

Factors influencing the exfoliation of cervicovaginal epithelial cells.

OBJECTIVE: Our objective was to investigate the association of smoking and exfoliation of cervicovaginal epithelial cells while controlling for other factors that may potentially influence cell exfoliation (e.g., presence of cervical intraepithelial neoplasia or koilocytes, the use of oral contraceptives, age, and the phase of the menstrual cycle). STUDY DESIGN: Cervicovaginal lavage specimens and epidemiologic questionnaires were obtained with informed consent from 190 women. The cervicovaginal lavage samples were processed to separate other contaminants. The number of squamous epithelial cells counted was expressed as cells per milliliter of lavage. RESULTS: Multiple linear regression analysis revealed that the number of exfoliated epithelial cells was significantly higher in smokers (p < 0.01) and also in women with cervical intraepithelial neoplasia (p < 0.05). The other studied variables had no detectable effect. CONCLUSION: The findings suggest that smoking or the presence of cervical intraepithelial neoplasia may induce an acceleration in the exfoliation of cervicovaginal epithelial cells. This may alter cell maturation and may be a factor in the oncogenic process.

Adolescent↗
PubMed1992

Purification and partial characterization of a penicillin-binding protein from Mycobacterium smegmatis.

Penicillin-binding proteins (PBPs), although characterized from several organisms, have so far not been studied in mycobacteria. The present study is the first characterization of a PBP from Mycobacterium smegmatis. The PBP was purified by solubilization of the membranes with Triton X-100 and successive chromatography of the solubilized proteins on ampicillin-linked CH Sepharose 4B and DE-52. The purified PBP (M(r), 49,500) catalyzed a model transpeptidase reaction with the tripeptide acetyl2-L-Lys-D-Ala-D-Ala as the substrate and Gly-Gly as the acceptor. The transpeptidase activity was inhibited by 50% at a benzylpenicillin concentration of 1.8 x 10(-7) M, which was similar to the concentration (1.1 x 10(-7) M) of benzylpenicillin required to saturate to 50% this PBP. Of several antibiotics tested, the concentration of antibiotic required to inhibit [35S]penicillin binding by 90% was found to be the lowest for cefoxitin and Sch 34343.

Amino Acid Sequence↗
PubMed1992

Endogenous estradiol and progesterone concentrations in smokers on oral contraceptives.

The simultaneous effects of cigarette smoking and oral contraceptives on serum estradiol and progesterone levels were investigated in 114 premenopausal women. Serum 17 beta-estradiol and progesterone levels were measured by radioimmunoassay. In smokers, estradiol and progesterone levels were significantly lower (p less than 0.025). In smokers using oral contraceptives, estradiol and progesterone levels were the lowest (p less than 0.001 and p less than 0.01, respectively). The findings suggest that smoking and oral contraceptives independently lower serum estradiol and progesterone concentrations in premenopausal women and that the effects may be additive.

Adolescent↗
PubMed1991

Altered erythrocyte protein kinase C activity and membrane protein phosphorylation in chronic myelogenous leukemia.

The membrane protein kinase C (PKC) content was found to be higher in erythrocytes form patients suffering from chronic myelogenous leukemia (CML) compared to normal erythrocytes. PKC activity was also higher in the cytosol and after translocation to the membrane, as assessed by histone phosphorylation. The increased PKC activity in CML erythrocytes was associated with abnormal phosphorylation of protein 4.1. Since phosphorylation-dephosphorylation mechanisms are likely candidates for controlling membrane protein associations, the altered PKC activity may be one of the factors responsible for altered thermal sensitivity and mechanical stability of CML erythrocytes.

Cytoskeletal Proteins↗
PubMed1991

Plasma levels of antioxidant beta-carotene and alpha-tocopherol in uterine cervix dysplasias and cancer.

Chronic human health problems, namely arteriosclerosis, myocardial ischemia, and cancer, may be caused by highly active oxygen species and may be preventable by antioxidant vitamins. In humans, the sources of two major antioxidants, beta-carotene and alpha-tocopherol, are dietary. In this study, we measured the plasma concentrations of beta-carotene and alpha-tocopherol by reverse-phase high-pressure liquid chromatography in a cross-sectional sampling of 116 women. Significantly reduced plasma levels of beta-carotene and alpha-tocopherol were observed in women with histopathologically diagnosed cervical dysplasias or cancer (p less than 0.0001 and p less than 0.005, respectively). There was an inverse association between the plasma levels of both beta-carotene and alpha-tocopherol and increasingly severe graded cervical histopathology. In groups with advanced dysplasias, the percentage of smokers was markedly increased and the women were comparatively older (p less than 0.0001). A strong association was noted between smoking status and plasma beta-carotene levels, independent of cervical pathology. However, this was not evident with respect to alpha-tocopherol. The findings suggest that the antioxidants beta-carotene and alpha-tocopherol have biologic functions that are interdependent in the pathogenesis of cervical intraepithelial lesions and cervical cancer.

Adolescent↗
PubMed1991

Defective mycolic acid biosynthesis in a mutant of Mycobacterium smegmatis.

A mutant of Mycobacterium smegmatis defective in mycolic acid biosynthesis was isolated following chemical mutagenesis. Fatty acids were extracted from the mutant and subjected to structural analysis by thin-layer chromatography and high-performance liquid chromatography (HPLC) of both methyl and p-bromophenacyl ester derivatives. Thin-layer chromatography did not show the presence of any fatty acid of RF comparable to that of standard methyl mycolate. The HPLC profile revealed a broad peak in the standard mycolic acid ester region. No characteristic peaks of mycolic acid esters comparable to the wild-type could be resolved. Mass spectral analysis of the HPLC-purified peak demonstrated the presence of shorter-chain fatty acids in the mutant. These data support the idea that the mutant accumulates precursors of mycolic acids and is incapable of carrying out the final conversion to mycolic acids of 60-90 carbon atoms.

Chromatography, High Pressure Liquid↗
PubMed1991

Plasma ascorbic acid and beta-carotene levels in women evaluated for HPV infection, smoking, and cervix dysplasia.

The association of the plasma levels of the essential micronutrients, ascorbic acid and beta-carotene, with smoking and human papillomaviruses (HPV) infection has been studied in 75 women referred to a colposcopy clinic for an abnormal Pap smear. Each patient had a repeat Pap smear and a colposcopically directed biopsy of a visually perceived cervix abnormality. Cervicovaginal lavage specimen and peripheral venous blood sample were obtained for HPV DNA hybridization studies and nutrient analyses, respectively. Samples were obtained and analyzed without knowledge of each woman's clinical status. A group of 45 subjects had histopathologically diagnosed dysplasias of varying grades of severity. Among women with dysplasias, 53.3% were smokers. Of subjects with and of subjects without dysplasias, 66 and 34%, respectively, were positive for HPV infection. The mean plasma reduced ascorbic acid, retinol, and beta-carotene levels between the dysplastic groups were comparable. A strong association with smoking history and plasma reduced ascorbic acid level was note independent of cervical dysplasias or HPV status. The findings underscore the importance of smoking, ascorbic acid, and beta-carotene as nutritional variables, and HPV infection in the pathogenesis of cervical dysplasias.

Adult↗
PubMed1991

An unusual presentation of neuroleptic malignant syndrome.

The neuroleptic malignant syndrome is an exceedingly rare but potentially fatal condition characterized by parkinsonian type rigidity, rise of temperature and altered consciousness. This idiosyncratic side-effect of almost all psychotic drugs though rare may occur even when neuroleptics are used for a short period. Here a very rare presentation of a case, of neuroleptic malignant syndrome appearing 2 days following 2nd dose of injection fluphenazine decanoate (0.5 ml) IM in whom 1st dose having 30 days prior to the 2nd one did not show any adverse effect, is being reported.

Adult↗
PubMed1990

Smoking and the antioxidant ascorbic acid: plasma, leukocyte, and cervicovaginal cell concentrations in normal healthy women.

The influence of cigarette smoking on the plasma, leukocyte, and cervicovaginal cell ascorbic acid levels in 46 healthy smokers and healthy nonsmokers was investigated. Coded peripheral venous blood and cervicovaginal lavage specimens obtained after informed consent were analyzed simultaneously for their ascorbic acid content. The findings suggest that smoking affects the levels and distribution of ascorbic acid. In smokers (n = 16), the number of exfoliated cervicovaginal epithelial cells and leukocyte ascorbic acid levels was significantly higher (p less than 0.01, p less than 0.05, respectively) compared with nonsmokers (n = 30). In addition, cervicovaginal cell ascorbic acid, plasma reduced and total ascorbic acid levels were significantly lower (p less than 0.001, p less than 0.01, p less than 0.01, respectively). The exfoliated epithelial cell ascorbic acid levels in nonsmokers was fourfold greater than that of leukocytes. The implications of these findings within the context of free radical-induced cellular pertubations in smokers are discussed.

Adult↗
PubMed1990

Changes in membrane lipids and amino acid transport in a nystatin-resistant Aspergillus niger.

A nystatin-resistant mutant of Aspergillus niger is described that has quantitative changes in phospholipid composition compared with the wild type. The proportion of linoleic acid in total phospholipids was elevated in the mutant from 38 to 56% and the proportion of oleic acid was lowered from 28 to 12%. Amino acid transport is also altered, the Vmax values for the uptake of leucine, lysine, and glutamic acid being generally higher in the mutant; for glutamic acid the increase was from 15 to 35 nmol.mg-1.min-1.

Amino Acids↗
PubMed1990

Measurements of ascorbic acid and glutathione in exfoliated cervicovaginal epithelial cells of smokers and women with cervical dysplasias.

This report emphasizes the ability to quantify ascorbic acid (AA) and reduced glutathione (GSH) levels in exfoliated cervicovaginal epithelial cells obtained by a lavage technique. Sixty-two women with abnormal Papanicolaou smears underwent colposcopic examinations. Colposcopic lesions were biopsied and histopathologically graded. Marked variations in the number of cells and in the levels of AA and GSH were observed. In cigarette smokers, the number of exfoliated cells retrieved was significantly higher (p less than 0.05, by Student's t test). The simultaneous investigation of biochemical and virologic parameters in exfoliated cervicovaginal epithelial cells, in conjunction with the known cytopathologic and epidemiologic risk variables, provides a novel approach to elucidate factor(s) that may inhibit or promote cervical carcinogenesis in designed prospective studies.

Adult↗