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Biomedical subjects

N M Rao

Publications and source records attributed to N M Rao.

At least 37 records · Page 2Linked to original sources
PubMed1992

Differential susceptibility of phosphatidylcholine small unilamellar vesicles to phospholipases A2, C and D in the presence of membrane active peptides.

Activities of phospholipases C and D along with A2 were followed on egg phosphatidylcholine small unilamellar vesicles in the presence of membrane active peptides melittin, gramicidin S and alamethicin. Decrease in the activity of phospholipase C and D and enhancement of phospholipases A2 activity suggest that these enzymes are sensitive to alterations in the lipid packing in the membranes in the presence of these peptides. Phospholipase C and D, which have not been used to study peptide--membrane interactions, have potential use in studying membrane perturbations, since their activities are very sensitive to lipid packing.

Alamethicin↗
PubMed1992

Pulmonary function studies in 15 to 18 years age workers exposed to dust in industry.

Pulmonary function tests (VC, FEV1% and FEF25-75%) were evaluated in 15 to 18 years age workers employed in slate pencil industry exposed to silica dust, in wool carpet industry exposed to wool dust and in diamond cutting and polishing exposed to carbon dust. These values were compared with the values obtained in clinically healthy non-smokers of the same age group. The results revealed significant impairment of VC in diamond workers, and FEF25-75% in slate pencil workers. When the values were observed according to smoking habits in diamond workers, VC, FEV1 and FEF25-75% were all significantly reduced in smokers whereas in non-smokers only VC was lowered significantly. Among slate pencil workers FEF25-75% was significantly reduced in both smokers and non-smokers. Wool dust exposed workers showed reduced values than normal subjects. The detailed results including the prevalence of various pulmonary impairments were presented.

Adolescent↗
PubMed1992

Pulmonary function status of shopkeepers of Ahmedabad exposed to autoexhaust pollutants.

The study deals with evaluation of pulmonary function status (VC, FEV1% and FEF25-75%) in Ahmedabad shopkeepers stationed near different traffic junctions and relating them with the levels of oxides of nitrogen (NOx) near these junctions categorised as Heavy, Medium and Low polluted area junctions. The pulmonary function test (PFT) values of heavy polluted and medium polluted area shopkeepers is compared with low polluted area shopkeepers. The influence of smoking habits and duration of exposure over PFT values was seen. The prevalence of airway obstruction in shopkeepers was compared with USA population. The results indicated significant impairment in FEV1% and FEF25-75% value in high polluted area shopkeepers where NOx level is much higher than TLV value. In medium polluted area, where NOx level is slightly higher than TLV value, shopkeepers demonstrated significant impairment in FEF25-75%. Smoking is found to have an additive effect. A linear increase in the prevalence of pulmonary impairment with increasing duration of exposure was evidenced. Shopkeepers exhibited higher prevalence of impairment in both smokers and non-smokers than USA population attributing it to the effect of autoexhaust pollutants. This study also denoted that FEF25-75% is an early indicator of obstruction in smaller airways which is the primary site of deposition of inhaled pollutants.

Air Pollutants↗
PubMed1992

Membrane instability in respiring mitochondria: role of phosphate.

Metabolically-induced (spontaneous) high amplitude swelling of mitochondria has been shown to be due to a serial disruption of the mitochondrial membranes [D. Sambasivarao & V. Sitaramam (1985), Biochim Biophys Acta, 806, 195-209]. Phosphate- and arsenate-induced swelling was investigated in mitochondria to evaluate the role of phosphate transport in the instability created in the mitochondrial membranes. Phosphate-induced swelling in respiring mitochondria was similar to spontaneous swelling. Both represent essentially colloidal swelling due to the variable porosity induced in the inner membrane to polyols by respiration. Swelling of non-respiring mitochondria at high ammonium phosphate concentrations was, on the other hand, primarily due to high permeability to phosphate. This membrane instability created by phosphate transport in the surrounding lipid involves neither the endogenous nor the exogenous Ca2+.

Animals↗
PubMed1992

Pulmonary function studies in Gujarati subjects.

In this study a multiple regression equation for prediction of ventilatory pulmonary function tests (FVC, FEV1%, FEF25-75% and PEFR) is developed in average healthy non-smoker male and female Gujarati subjects. The average adult female values showed a reduction varying from 21.0 to 29.0% compared to adult male subjects. There is a deviation of the present study values from other studies in Indian subjects and values from European studies are higher than the present values. This study demonstrated that the present regression equation is the most ideal and appropriate for prediction of pulmonary function values in Gujarati subjects either for assessing physical fitness in normal subjects or for determining the pattern of ventilatory impairment in respiratory disease patients. The pulmonary function values assessed by substituting the average age, height and weight of females in male regression equation revealed lower values in females ranging from 14.0 to 19.0% attributable only due to difference in sex.

Adolescent↗
PubMed1991

Anomalous stimulation of Escherichia coli alkaline phosphatase activity in guanidinium chloride. Modulation of the rate-limiting step and negative cooperativity.

Guanidinium chloride stimulates the activity of alkaline phosphatase from Escherichia coli, by 3-4-fold. Structural parameters of the enzyme, monitored by fluorescence and circular dichroism, indicate progressive denaturation. This unusual stimulation is shown to be independent of the nature of the substrate and source of the enzyme. Profiles of pH dependence and transphosphorylation reaction indicate that the dephosphorylation step of the catalysis is enhanced in the presence of guanidinium chloride. We demonstrate, by fast-flow kinetics and inhibitor titrations, that guanidinium chloride enhances activity by abolishing negative cooperativity and by accelerating the dissociation of rate-limiting enzyme and substrate (E.P) complex.

Alkaline Phosphatase↗
PubMed1991

Protease inhibitors from ripened and unripened bananas.

The proteolysis of casein by trypsin, chymotrypsin and papain was inhibited by ripened and unripened bontha, poovan, nendran, cavendish and rasthali bananas. The inhibition of trypsin, chymotrypsin and papain by different ripened banana cultivars was much more than that of unripened banana cultivars. The trypsin and chymotrypsin inhibitory activity of ripened poovan was heat stable, resistant to pronase and partly stable to trypsin but the trypsin and chymotrypsin inhibitory activity of unripened poovan was stable to heat and resistant to pronase only. The partial stability of trypsin inhibitory activity and instability of papain inhibitory activity of ripened poovan to alkaline pH suggests that the inhibitory factors of trypsin and papain were dissimilar. The probable role of unripened banana papain inhibitors in curing stomach ulcers and antinutritional role of ripened banana trypsin inhibitors is discussed.

Fruit↗
PubMed1990

Acute and chronic changes in pulmonary functions among Indian textile workers.

An epidemiological study was carried out in three textile mills of Ahmedabad. A total of 214 cotton dust exposed and 184 control subjects were examined for pulmonary function tests. Pulmonary function tests included forced vital capacity and forced expiratory volume in one second. The pulmonary function tests were carried out before starting the shift and after 7 hours of exposure on a vitalograph spirometer. The study shows that among the cotton dust exposed workers byssinotics behave distinctly and show the maximum acute and chronic changes in pulmonary functions. It seems that the effect of cotton dust exposure on the byssinotic subjects is more predominant than the effect of smoking.

Adult↗
PubMed1989

A recycling assay for alkaline phosphatase applied to studies on its transport in E. coli K12.

A recycling assay for alkaline phosphatase, based on its ability to hydrolyse NADP to NAD+, is presented. The product NAD+ is recycled in a coupled assay consisting of NADH regeneration and reduction of a nitroblue tetrazolium salt. This assay is 10-12 times more sensitive than the conventional assay. We demonstrate the role of energy poisons in transport of this protein into the periplasm by combining the improved detection with phase separation of the periplasmic and cytoplasmic alkaline phosphatase pools.

Alkaline Phosphatase↗
PubMed1988

ATP hydrolysis induces variable porosity to mannitol in the mitochondrial inner membrane.

Osmotic titration of ATPase activity in rat liver mitochondria was consistent with enhanced porosity of the mitochondrial inner membrane to mannitol due to ATP hydrolysis even when endogenous respiration was inhibited by rotenone. The occluded ATPase activity, which exhibits osmotic activation with an optimum near isotonicity, depends both on the ATPase activity per se and on the activity of the ADP/ATP carrier. Purified ADP/ATP carrier incorporated into small, unilamellar liposomes was critically shown to exhibit dependence of its activity on the osmotic pressure differences across the membrane, with maximal activity corresponding to isotonicity, regardless of the actual internal tonicity.

Adenosine Triphosphate↗
PubMed1986

Anomalous permeability and stability characteristics of erythrocytes in non-electrolyte media.

The permeability characteristics of the erythrocyte membrane were critically evaluated in electrolyte and non-electrolyte (sucrose) media by ion-selective electrodes and radioactive polyol fluxes as well as by the novel technique of osmometry. K+ efflux demonstrated a linear osmotic susceptibility distinct from Na+ influx upon incubation in NaCl media of various tonicities. In non-electrolyte media, acidification of the medium, large fluxes of K+, sucrose and even haemoglobin (as manifest by hypertonic disruption) were consistent with enhanced porosity of the bilayer due to the field created by surface charge density leading to density fluctuations in the bilayer.

Animals↗