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Biomedical subjects

U Singh

Publications and source records attributed to U Singh.

At least 91 records · Page 5Linked to original sources
PubMed1990

Formation of UDP-2-acetamido-2-deoxy-L-galactose and UDP-2-acetamido-2-deoxy-L-galacturonic acid by Pseudomonas aeruginosa.

The O-specific polysaccharide from the lipopolysaccharide of Pseudomonas aeruginosa NCTC 8505 (IATS serotype O:3) consists of a tetrasaccharide repeating unit comprising L-rhamnose, N-acetyl-D-glucosamine (GlcNAc), bacillosamine, and N-acetyl-L-galactosaminuronic acid (L-GalNAcA) (Y. Tahara and S. G. Wilkinson, Eur. J. Biochem. 134:299-304, 1983). Incubation of GlcN or UDP-GlcNAc with cell extracts or EDTA-treated cells of P. aeruginosa NCTC 8505 yielded a mixture of UDP-ManNAc, UDP-GalNAc, UDP-GlcNAcA, UDP-ManNAcA, UDP-L-GalNAc, and UDP-L-GalNAcA. The last two compounds, here identified for the first time, may be intermediates in the synthesis of the L-GalNAcA moiety of the O-specific portion of the lipopolysaccharide of P. aeruginosa.

Glucosamine↗
PubMed1990

Implantation of fetal thymus and sympathetic ganglion within the anterior eye chamber in mice, to study neuro-immune interaction in thymic development.

In this study 13- to 14-day fetal thymic lobes were implanted within the anterior eye chambers in mice either with or without a syngeneic newborn sympathetic ganglion. It was observed after 6 weeks of implantation that the thymic lobes that grew with the ganglia had fewer lymphoid cells than their counterparts which were grown without the ganglia. The cells that developed within the thymic lobes were Thy-1- and peanut agglutinin-positive. The thymic lobes that grew with sympathetic ganglia also showed the presence of adrenergic nerves, perhaps due to reinnervation of the thymic grafts from the ganglia.

Animals↗
PubMed1990

Patterns of erythropoiesis and anaemia in malaria.

Of 138 patients with malaria, 90 were found to be having Plasmodium falciparum in their peripheral blood smears. Megaloblastosis alone or in combination with the other patterns of erythropoiesis was observed in 82.1 percent cases of chronic P. falciparum malaria as compared to 36.3 and 26.5 per cent cases of acute P. falciparum and P. vivax malaria respectively. Iron deficiency was observed in 15.5 percent cases of chronic P. falciparum, 18.2 per cent cases of acute P. falciparum and 13.3 per cent patients of P. vivax infection. Of patients with chronic falciparum malaria, 33.3 percent revealed features of both megaloblastosis and defective iron utilization and transient hypoplasia of marrow was observed in 8.9 per cent of these cases.

Adolescent↗
PubMed1990

Comparative evaluation of marginal leakage of different types of silver amalgam alloys in vitro--a microfluoroscopic study.

A study was carried out in vitro to evaluate the amount of microleakage using seven different Silver amalgam alloy using Fluorescein dye. Among the high copper alloy used in this study, the admixed alloy showed least marginal leakage followed by the high copper lathecut alloy and the high copper spherical alloy. It was also observed that the marginal penetration of the conventional alloy are much more than the high copper alloy.

Adult↗
PubMed1990

Circulating iso and auto antibodies to human spermatozoa in infertility.

Blood samples from 50 couples of unexplained primary infertility and 25 healthy fertile couples were tested for antispermatozoa antibodies (ASA) by gelatin agglutination test and sperm immobilising complement dependent cytotoxicity test. The incidence of sperm agglutinating and sperm immobilising antibodies was found to be 14 per cent and 10 per cent respectively in infertile couples. Agglutinating antibodies were detected in 18 per cent males and 16 per cent of females while cytotoxic antibodies were found in 14 per cent males and 10 per cent of females. Only 4 per cent of the normal fertile couples taken as a control group showed positive ASA, hence the difference in incidence of positive ASA between the infertile and fertile couples was found to be statistically significant. Also, the agglutination test was observed to be more sensitive than the cytotoxicity test.

Agglutination Tests↗
PubMed1989

Inhibition of rat liver microsomal estrogen 2-hydroxylase by 2-methoxyestrogens.

The inhibition of estrogen 2-hydroxylase by 2-methoxyestrogens was demonstrated in screening assays and has been further investigated under initial velocity conditions. The ability of 2-methoxyestradiol and 2-methoxyestrone to block the conversion of estradiol to 2-hydroxyestradiol by male rat liver microsomal preparations was determined by measuring the release of 3H2O from [2-3H]estradiol. The apparent Kis were found to be 34.86 microM for 2-methoxyestradiol and 18.65 microM for the methoxyestrone, with the apparent Km for the substrate estradiol in these essays of 3.21 microM. Mixed inhibition studies with the methoxyestrogens and 2,4-dibromoestradiol, an effective estrogen 2-hydroxylase inhibitor, in male rat liver microsomes resulted in Dixon plots consisting of a series of parallel lines. Thus, methoxyestrogens and 2,4-dibromoestradiol are mutually exclusive inhibitors, i.e., the binding of one compound to the enzyme interferes with the binding of the other. These results indicate that the compounds are interacting at the same enzymatic site. Finally, a method utilized to measure estrogen 2-hydroxylase activity in vitro is a radioenzymatic assay involving addition of catechol o-methyltransferase (COMT) and radiolabeled S-adenosylmethionine, and the amount of catechol estrogens formed is determined by the amount of radiolabeled methoxyestrogens isolated. The results described here demonstrate inhibition of estrogen 2-hydroxylase by methoxyestrogens; however, under enzymatic conditions of low product formation, the estrogen 2-hydroxylase inhibitory effect of catechol estrogen products from the radioenzymatic assay would be insignificant. Thus, these interactions of methoxyestrogens suggest that the steroid hormonal environment be considered in the examination of estrogen 2-hydroxylase and the catechol estrogen products. off

2-Methoxyestradiol↗
PubMed1989

Effects of dilazep in evolving myocardial infarction in dogs: a biochemical study.

Mongrel dogs of either sex with ligation of their left anterior descending coronary artery were employed for the present study to investigate the biochemical basis of the cardioprotective action of dilazep. Dilazep (0.2 mg/kg intravenous) was administered 20 minutes after coronary arterial occlusion. Ligation of the artery for 40 minutes increased the tissue lactate concentration and decreased the adenosine triphosphate molecules within the occluded bed. Dilazep decreased the lactate concentration and improved the adenosine triphosphate content of this bed significantly. Dilazep also lowered the tissue cyclic adenosine monophosphate concentration and free fatty acid extraction of the ischemic myocardium as studied 40 minutes after coronary arterial ligation. It can be inferred that less free fatty acid extraction and calcium antagonistic action of dilazep helps in restoring mitochondrial function. Furthermore, decreased tissue lactate concentration resulted after better perfusion of the occluded bed and helped in greater generation of adenosine triphosphate molecules. These favorable biochemical and metabolic changes contribute to the cardioprotective action of dilazep.

Adenosine Triphosphate↗
PubMed1989

Bacteroides gingivalis vesicles mediate attachment of streptococci to serum-coated hydroxyapatite.

Outer membrane vesicles purified from Bacteroides gingivalis culture supernatant bound to serum coated hydroxyapatite (SeHA). The immobilized vesicles served as receptors for a number of species of oral streptococci. The binding of Streptococcus sanguis 12 to SeHA was increased 10 times by the vesicles. Vesicle-associated binding increased proportionally with an increase in the number of bound vesicles. Arginine and lactose both partially reduced binding of S. sanguis. Heating the vesicles destroyed their binding ability whereas heating S. sanguis reduced but did not eliminate vesicle-mediated binding.

Bacterial Adhesion↗
PubMed1989

An extension of a model for first birth interval and some social factors.

"A model for the time of first birth is presented under certain assumptions, which involve biological and socio-cultural factors." The model is illustrated using data from Rural Development and Population Growth--A Sample Survey, 1978, conducted in Varanasi, India, and involving some 3,514 households.

Asia↗
PubMed1989

Bacillaemia and bone marrow involvement in leprosy.

Fifty patients (24 new and 26 receiving specific treatment) of leprosy were investigated to study the concentration and morphological index (MI) of the lepra bacilli in skin, peripheral blood and bone marrow. The organisms were detected in 28 cases on skin slit smear examination, in 38 cases on bone marrow examination and in 38 cases on examination of smears made from buffy coat of peripheral blood. Out of 22 cases negative for the bacilli on skin slit smears, 15 had the organisms either in buffy coat or bone marrow or both. Acid fast bacilli in peripheral blood and bone marrow with skin smear negativity were mainly observed in patients with paucibacillary type of the disease and in those who were receiving treatment. Examination of buffy coat and bone marrow for presence of lepra bacilli is suggested to establish the diagnosis in doubtful cases.

Bone Marrow↗
PubMed1989

Serum glycoproteins in pulmonary tuberculosis.

Serum glycoprotein levels were studied in 50 patients of pulmonary tuberculosis and 25 healthy controls. Ten of the tuberculosis patients had stage I disease, 24 stage II, 9 stage III and 7 had pulmonary tuberculosis with effusion. The serum levels of protein bound hexose, protein bound hexosamine, protein bound fucose and protein bound sialic acid were significantly higher (P less than 0.001) in patients with pulmonary tuberculosis as compared to controls; the mean values being 195.6, 189.1, 16.3 and 120.8 mg/dl respectively in patients and 117.0, 84.1, 7.7 and 67.2 mg/dl respectively in controls. The levels were not influenced by age and sex of the subjects in both groups. The levels were found to increase in all the stages of pulmonary tuberculosis with a marginal difference. Treatment with antituberculosis drugs resulted in a decrease in ESR and the various fractions of serum glycoproteins at subsequent follow up, however, the mean levels did not reach those of control subjects and were not influenced by the type of therapy.

Adolescent↗
PubMed1988

Antinutritional factors of chickpea and pigeonpea and their removal by processing.

Protease inhibitors, amylase inhibitors, phytolectins, polyphenols, and oligosaccarides are important antinutritional factors of chickpea and pigeonpea. Research on these factors is reviewed and compared to those in other grain legumes. Both chickpea and pigeonpea are consumed in various forms as processed food. The effects of such processing practices as cooking, germination, and fermentation to reduce the levels of these antinutritional factors are also discussed.

Amylases↗
PubMed1988

Comparison between serum isonicotinic acid hydrazide (INH) levels and urinary sulfadimidine (sulfamethazine) acetylation as predictors of INH acetylator status.

The acetylator status of 40 children with pulmonary tuberculosis was investigated by (1) sulfadimidine (SDM; sulfamethazine) acetylation test in urine and (2) estimation of isonicotinic acid hydrazide (INH) levels. The antimode was at 70% based on the frequency distribution of SDM acetylation. Children acetylating less than 70% of administered SDM were taken as slow acetylators while those with more than 70% as rapid acetylators. The serum INH antimode was at 0.85 micrograms/ml. Thus serum values less than 0.85 micrograms/ml categorised a child as rapid and those with more than 0.85 micrograms/ml as slow acetylators. The sensitivity of these two methods was similar with a correlation coefficient r = 0.64. Thus the determination of the type of acetylator by SDM acetylation test is equally reliable and technically simpler and is recommended instead of INH serum concentration.

Acetylation↗