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Biomedical subjects

M Singh

Publications and source records attributed to M Singh.

At least 865 records · Page 48Linked to original sources
PubMed1989

Drug resistance and colicin production among various serotypes of Escherichia coli of animal origin.

One hundred and twenty two strains of E. coli isolated from clinical conditions of animals were studied for the production of colicins and their sensitivity behaviour towards 16 antibiotics and trimethoprim-sulphamethoxazole. Out of 122 strains, 27 (22.1%) were found colicinogenic and 25 (93%) of these colicinogenic strains were found resistant to one or more of drugs in various combinations. All the 27 colicinogenic strains could be typed into 15 serogroups. Serogroup 084 was found predominant. Transfer of R-plasmids and Col-plasmids were observed in 5 (18.5%) strains individually. In one strain both drug resistance and colicin production determinants were transferred enblock. Such transconjugants will be more invasive and virulent and will create serious chemotherapeutic problems.

Animals↗
PubMed1989

Systemic oxygen uptake during hypothermic cardiopulmonary bypass. Effects of flow rate, flow character, and arterial pH.

A factorial experiment was undertaken to study the effects on systemic oxygen uptake of alteration in flow rate between 1.5 and 2.0 L.min-1.m-2, flow character between nonpulsatile or pulsatile perfusion, and acid-base management between attempted pH and alpha stat control during hypothermic cardiopulmonary bypass. Twenty-four patients undergoing elective coronary bypass were studied. After 10-minute periods of stability at moderate hypothermia (28 degrees +/- 1 degrees C), blood samples were aspirated from the arterial and venous lines. Samples were analyzed for oxygen content, saturation, and tension, pH, base excess, and lactate. Systemic oxygen uptake was significantly greater at 2.0 than 1.5 L.min-1 m-2 by 18 (7, 30) ml.min-1.m-2, whereas it was not significantly affected by change in flow character (-4[-16, 7] ml.min-1.min-2) or arterial pH (-2 [-12, 8] ml.min-1.m-2 per 0.1 pH unit). Venous oxygen tension, saturation, and content were significantly increased at the higher compared with the lower flow rate (p less than 0.05), whereas arterial oxygen tension and oxygen extraction were not. Increases in arterial oxygen content and saturation from low to high flow rates were marginally nonsignificant (F = 4.08, critical value = 4.17; F = 3.99 critical value = 4.21). Base excess was significantly affected by alteration in arterial pH but not flow rate, flow character, or stage (p less than 0.05). Lactate concentrations were unaffected by flow rate, flow character, or arterial pH, but there was a small but significant overall decrease during the course of cardiopulmonary bypass (p less than 0.05). Reasons why systemic oxygen uptake was affected by flow rate but not by flow character or arterial pH are discussed. A flow rate of 1.5 L.min-1.m-2 during cardiopulmonary bypass with moderate hypothermia results in a less than maximal systemic oxygen uptake.

Acid-Base Equilibrium↗
PubMed1989

A comparison of the ELISA with other serological tests in the serodiagnosis of amoebiasis.

The sera of 78 patients with invasive amoebiasis were tested for antiamoebic antibodies by the techniques of enzyme-linked immunosorbent assay (ELISA), indirect haemagglutination (IHA), indirect fluorescent antibody (IFA) and counterimmunoelectrophoresis (CIEP). Results showed that the ELISA compared favourably with IHA and IFA tests in terms of sensitivity and specificity. ELISA, IHA and IFA detected 97.4%, 96.2% and 98.7% of the patients respectively. CIEP was the least sensitive of the 4 serological methods with a sensitivity of 88.5%. The advantages and disadvantages of the 4 serodiagnostic procedures are discussed.

Amebiasis↗
PubMed1989

Alterations in testicular functions in patients of scrotal hydrocele.

Forty three randomly selected patients of scrotal hydrocele were investigated for alterations in functions of the testes. FSH and LH levels were raised in 50 and 75 per cent of patients respectively whereas testosterone level was found subnormal in 14 of the 28 patients in whom hormone profile was studied. LH and FSH levels also showed some relation with duration and size of the hydrocele. Similarly, sperm concentration and their motility was found affected by the duration of the disease.

Adult↗
PubMed1989

The determination of anti-Toxoplasma gondii antibodies in different IgG subclasses of human sera by the enzyme-linked immunosorbent assay (ELISA).

The level of activity of the 4 IgG subclasses in toxoplasmosis were determined in an ELISA employing commercially available monoclonal antibodies to the 4 subclasses. Forty-four sera positive by IgG-ELISA and 73 negative sera were tested for IgG subclass activity. IgG1 was found to be the predominant subclass while IgG3 and IgG4 were probably produced at low but significant levels in sera which were positive for IgG antibodies. The significance of the results were discussed.

Adult↗
PubMed1989

Ankle and wrist weights: their effect on physiologic responses during treadmill running.

This study examined the effects of ankle and wrist weights on acute physiologic responses during treadmill running. Eight physically active young men completed eight running tests at their predetermined "most comfortable" speeds with zero, 1.6, 3.2, and 4.8 kg of additional weight equally distributed on the ankles or wrists. Energy expenditure and heart rate increased as a linear function of the additional weight placed at both anatomic locations. The magnitudes of these responses were significantly higher with the weights at the ankles than at the wrists, and were independent of the strength and endurance of the pertinent muscle groups involved in overcoming the additional weight. Blood lactate concentrations tended to increase during the loaded runs. However, the values were not significantly different from those observed during control (zero load) runs. Perceived exertion increased significantly over the control value when the heaviest weights were placed at the ankles and wrists. Since ankle and wrist weights increase training intensity and energy expenditure during treadmill running, they may result in greater increases in cardiovascular fitness and greater weight loss than would be realized by training without their use.

Adult↗
PubMed1988

Hydrocephalus in asphyxiating thoracic dystrophy.

We document four patients, including two sibs, with asphyxiating thoracic dystrophy and mild congenital hydrocephalus. All infants were males; three had postaxial polydactyly. The CT scan of brain showed moderate dilatation of the lateral ventricles in all cases. This appears to be the first documentation of apparent hydrocephalus in this condition.

Asphyxia↗
PubMed1988

Antibody directed targeting of methotrexate-containing small unilamellar vesicles.

The potential of antibody-linked SUVs containing MTX in anticancer therapy was investigated. The SUVs, mean diameter 50 +/- 20 nm, were prepared by probe sonication of MTX-containing MLVs and were covalently linked either to a RAMG or NRG. After incubation with M21 melanoma cells for 2 h, RAMG-linked SUVs showed 2 and 4 times more binding than NRG-linked MTX-containing SUVs or MTX-containing SUVs unlinked to any Ig. Furthermore, on incubating M21 melanoma cells with RAMG-linked 3H MTX-containing SUVs for 2, 4, and 8 h at 4 degrees C or 37 degrees C, a higher radioactivity was associated with cells at 37 degrees C than at 4 degrees C. Membrane immunofluorescence revealed aggregation of and cap formation by RAMG-linked SUVs after 2 h (37 degrees C) and endocytosis at 4 and 8 h at 37 degrees C. Electron microscopic and autoradiographic studies confirmed aggregation of 3H MTX-containing SUVs around and on the surface of M21 cells. Electron microscopy also revealed these SUVs inside invaginations of and under the plasma membrane of melanoma cells. A colony inhibition assay showed that RAMG-linked, MTX-containing SUVs were 60 times, 8 times, and 4.5 times more growth inhibitory than free MTX, NRG-linked MTX-containing SUV, and MTX-containing SUVs unlinked to any Ig, but not toxic to a human kidney cancer line (that did not react with RAMG).

Antibodies, Neoplasm↗
PubMed1988

Localization and physical mapping of a plasmid-borne 23-kb nif gene cluster from Enterobacter agglomerans showing homology to the entire nif gene cluster of Klebsiella pneumoniae M5a1.

A physical and genetical map of the plasmid pEA3 indigenous to Enterobacter agglomerans is presented. pEA3 is a 111-kb large plasmid containing a 23-kb large cluster of nif genes which shows extensive homology (Southern hybridization and heteroduplex analysis) to the entire nif gene cluster of Klebsiella pneumoniae (Kp) M5a1. All the nif genes on pEA3 are organized in the same manner as in K. pneumoniae, except nifJ, which is located on the left end of pEA3 nif gene cluster (near nifQB). A BamHI restriction map of pEA3 and a detailed restriction map of the 23-kb nif region on pEA3 is also presented. The nif genes of pEA3 showed a low level of acetylene reduction in Escherichia coli, demonstrating that these genes are functional and contain the whole genetic information required to fix nitrogen. The origin of vegetative replication (OriV) of pEA3 was localized about 5.5 kb from the right end of the nif gene cluster. In addition to pEA3, large plasmids from four other strains of E. agglomerans showed homology to all the Kp nif genes tested, indicating that in diazotrophic strains of E. agglomerans nif genes are usually located on plasmids. In contrast, in most of the free-living, nitrogen-fixing bacteria the nif genes are on chromosome.

DNA Restriction Enzymes↗
PubMed1988

Simple tricoloured measuring tapes for identification of low birthweight babies by community health workers.

A total of 446 singleton neonates were subjected to measurements of birthweight, chest circumference (CC) and mid-arm circumference (MAC). A high degree of correlation between birthweight and CC as well as MAC was observed. Chest circumference correlated better with birthweight than MAC. Further analysis of data showed that CC measurements of less than or equal to 30.0 cm and less than or equal to 27.5 cm reliably identify neonates less than 2500 g and less than 2000 g, respectively, with a high degree of specificity and predictive value. The corresponding values for MAC were less than or equal to 9.0 cm and less than or equal to 8.5 cm, respectively. Using these inferences, two tricoloured measuring tapes, one each for CC and MAC, are proposed as simple screening tools for use by primary health workers for identifying low-birthweight neonates in the community without resorting to weighing scales.

Anthropometry↗
PubMed1988

In vitro assay of pancreatic acinar-cell function of rats made chronically riboflavin deficient.

To determine the effect of riboflavin deficiency on the rat pancreas, one-third of a group of rats was fed a purified riboflavin-sufficient diet ad libitum and two-thirds were fed isocaloric amounts of riboflavin-deficient diet for 13 wk; one-half of the latter group was replenished with daily intraperitoneal injections of riboflavin for the last 3 wk. Body weight, pancreas weight, DNA, protein, amylase, chymotrypsinogen, and trypsinogen decreased in riboflavin-deficient animals. In vitro basal secretion of chymotrypsinogen decreased and basal and bethanechol-stimulated secretions of trypsinogen increased in riboflavin-deficient rats. These changes were considered to be caused by relative inanition resulting from decreased food consumption. On replenishment of riboflavin, amylase content reverted to that of animals fed ad libitum whereas increases in body weight, pancreas weight, DNA, protein, chymotrypsinogen, and trypsinogen were not statistically significant. Both basal- and bethanechol-stimulated secretions of chymotrypsinogen increased. These data indicate that riboflavin deficiency, which commonly accompanies chronic alcoholism, may contribute to the pancreatic injury in chronic alcoholism.

Amylases↗
PubMed1988

NADPH generation in Aspergillus nidulans: is the mannitol cycle involved?

A cyclic pathway of NADPH generation involving interconversion of mannitol and fructose has been proposed to occur in fungi. In Aspergillus nidulans three enzymes of this proposed mannitol cycle (hexokinase, NADP-mannitol dehydrogenase and mannitol-l-phosphate phosphatase) were shown to be localized exclusively in the cytosol. Two isoenzymes of the fourth enzyme (mannitol-l-phosphate dehydrogenase) were detected and shown to be localized respectively in the mitochondrion and the cytosol. The mitochondrial isoenzyme appeared to be present on the outer face of the inner mitochondrial membrane. No evidence was found for a coordinated change in the maximal activities of the enzymes of the proposed mannitol cycle in extracts prepared from mycelia grown on six different carbon, and three different nitrogen sources nor for any increase in these activities induced by growth on NO3-. Studies of this type in which other NADP-linked dehydrogenases were measured showed that for most carbon sources tested growth on NO3- increased the maximal activity of NADP-isocitrate dehydrogenase as well as that of glucose-6-phosphate and 6-phosphogluconate dehydrogenases but had little effect on the maximal activity of NADP-malate dehydrogenase (decarboxylating). Our studies provide no support for the operation of the mannitol cycle, or for the proposed role of this cycle in NADPH generation in A. nidulans.

Adenylate Kinase↗
PubMed1988

Biotransformation of Dehydroabietic, Abietic, and Isopimaric Acids by Mortierella isabellina Immobilized in Polyurethane Foam.

Polyurethane foam supports immobilization of Mortierella isabellina ATCC 38063, a zygomycete that hydroxylates and thereby detoxifies resin acids found in certain pulp mill effluents. The fungus becomes entrapped as it threads growing mycelia through the open foam matrix. The tenacity of binding and the amount of biomass bound depend on initial spore numbers and nutrient concentration. Optimal dehydroabietic acid transformation occurs with early-stationary-phase foam-bound mycelia suspended in buffer at pH 6.5 to 8.5 with aeration >0.1 liter liter min and near a temperature maximum of 33 degrees C. Neither a greater number of similarly loaded foam cubes nor a greater surface area for similar amounts of biomass increased transformation rates. Compared to free mycelial cultures, foam presence retards growth and decreases the rate of precursor transformation but does not alter the nature of the metabolites formed from dehydroabietic acid, abietic acid, or isopimaric acid. Diffusional barriers or binding of substrates in an inaccessible manner may cause the observed inhibitions. Overall, foam immobilization stabilizes enzymic activity and is a facile laboratory process with scaleup potential.

Journal Article↗
PubMed1988

Surgery of aphakic retinal detachment.

In a prospective study 84 patients with aphakic retinal detachment were treated either by local scleral buckling alone or combined with an encirclement. The rate of surgical reattachment of the retina was found to be similar with either technique over a minimum follow-up period of one year. Simplicity and a low incidence of serious complications of the local procedure merit its application as the initial method of repairing aphakic detachments.

Adult↗