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Biomedical subjects

B L Gupta

Publications and source records attributed to B L Gupta.

At least 19 recordsLinked to original sources
PubMed1992

Effect of insulin and thyroxine on catalase, glutathione-s-transferase, GSH and GSSG in alloxan diabetic rat red cells.

The levels of catalase (CAT), glutathione-s-transferase (GST), reduced glutathione (GSH) and oxidised glutathione (GSSG) were measured in red blood cells from control (C) and diabetic rats (D). Diabetes was induced by alloxan administration and diabetic rats were treated with insulin (D+I) and thyroxine (D+T4). On the third day of insulin withdrawal the CAT activity increased significantly. The GST activity showed an increase in D and D+I for one week, thyroxine treatment to D rats resulted in maintaining the GST activity at control levels. The levels of GSH and GSSG increased in D red cells after one week of insulin withdrawal but later, the GSH level was below the control level while the GSSG was at its control level. Insulin treatment to D rats did not reverse GSH level to control initially but controlled it at a later stage. Thyroxine, though, reversed GSH levels but enhanced GSSG in D rat red cells.

Animals↗
PubMed1991

Ted Hall and the science of biological microprobe X-ray analysis: a historical perspective of methodology and biological dividends.

This review surveys the emergence of electron probe X-ray microanalysis as a quantitative method for measuring the chemical elements in situ. The extension of the method to the biological sciences under the influence of Ted Hall is reviewed. Some classical experiments by Hall and his colleagues in Cambridge, UK, previously unpublished, are described; as are some of the earliest quantitative results from the cryo-sections obtained in Cambridge and elsewhere. The progress of the methodology is critically evaluated from the earliest starts to the present state of the art. Particular attention has been focused on the application of the method in providing fresh insights into the role of ions in cell and tissue physiology and pathology. A comprehensive list of references is included for a further pursuit of the topics by the interested reader.

Animals↗
PubMed1990

Effect of hyperthyroidism and hypothyroidism on rat red blood cell insulin receptors and catecholamines: relationship with cellular ageing.

Insulin receptor activity and its relationship with catecholamines in rat young, middle aged and old red blood cells were investigated in experimental hypothyroidism and hyperthyroidism. In control animals, a loss of insulin receptor activity was found with cellular ageing and increased levels of norepinephrine, epinephrine and glycosylated hemoglobin. There was down regulation of insulin receptors together with alterations in membrane bound catecholamines in thyroid hormones imbalances. These results suggest that loss of insulin receptor in cellular ageing is probably part of a more generalised alteration and rat serves as an excellent model in defining the role of thyroid hormones in carbohydrate tolerance.

Animals↗
PubMed1990

Rat brain insulin degrading enzyme in insulin and thyroid hormones imbalances.

Rat brain insulin degrading enzyme activity and its relationship with insulin receptor were investigated in experimental hyperglycemia, hyperinsulinemia, hypothyroidism and hyperthyroidism. Insulin degrading enzyme activity was assessed in synaptosomes and high speed cytosol using [125I]insulin. Levels of insulin degrading enzyme were changed in high speed cytosol in insulin and thyroid hormone imbalances. These results suggest that insulin degrading enzyme in brain is predominantly active in cytosol and is subject to regulation by insulin and thyroid hormones. Probably it plays some role in long term effects of insulin in brain.

Animals↗
PubMed1990

Changes in erythrocyte glutathione peroxidase and glutathione reductase in alloxan diabetes.

Glutathione peroxidase and glutathione reductase activities were measured in erythrocytes from control, diabetic and insulin-treated diabetic rats. A significant decrease in the activity of glutathione peroxidase and an increase in the glutathione reductase activity were found with increase in the time of diabetes which may result in the alteration in the activity of the pentose phosphate pathway by the modulation of the levels of NADPH. Insulin administration reverses the change in the activity of glutathione peroxidase but does not reverse the glutathione reductase activity during diabetes. The overall changes may be due to changes in the levels of insulin, triiodothyronine and thyroxine.

Animals↗
PubMed1989

Susceptibility of clinical isolates to cephalexin, cefazolin and cefotaxime.

Three hundred and seventeen recent clinical isolates were tested for in vitro susceptibility to the three cephalosporins available in India--cephalexin, cefazolin and cefotaxime by the Kirby--Bauer disc diffusion method. Cefazolin was the most effective cephalosporin against Gram positive cocci (71.8% sensitive) followed by cefotaxime (62.7%) and cephalexin (52.7%). Cefotaxime was very effective against commonly isolated Gram negative bacilli with only 10 (8.8%) isolates being resistant to it while 44 (39%) and 65 (57.5%) were resistant to cefazolin and cephalexin, respectively. All isolates of Pseudomonas aeruginosa were resistant to cephalexin and cefazolin and only 29 (32.6%) were sensitive to cefotaxime.

Cefazolin↗
PubMed1989

The relationship of mucoid substances and ion and water transport, with new data on intestinal goblet cells and a model for gastric secretion.

It is known from the physical chemistry that mucoid substances (glycosaminoglycans, proteoglycans, glycoproteins) constitute polyanionic gels with anomalous colligative behaviour and differential preference for binding some cations such as H+, K+, Ca2+. The mucus secreting membranes in animals also constitute ion and water transporting epithelia with morphologically characterised pericellular compartments. These pericellular compartments are not free-fluid spaces as is assumed in conventional physiological thought, but contain polyanionic mucoid matrices with a prevalence of sulphated varieties such as heparan sulphates. Measurements with electron probe X-ray microanalysis of cryosections (EPXMA) show that at the various pericellular sites the local dry mass of these matrices can vary from less than 5% to greater than 30% of the wet mass. EPXMA measurements in several epithelia from insects and from vertebrates (gastro-intestinal tract) also show that the total concentrations of the major chemical elements (P, S, Na, K, Mg, Cl) at these pericellular sites is distinct both from their concentrations in the cytoplasm and in the bulk mucosal and serosal compartments. In all the examples a particular role of pericellular polyanions in sequestering K+ and Ca2+, and excluding Cl- is indicated. It is proposed that the general K-sequestering ability of these pericellular mucoids conserves the K+ ions leaking out of the cells and thus reduces the energy load for active transport in the cells through a K-recycling mechanism. In the midgut caeca of the desert locust, Schistocerca gregaria a dense mucoid matrix (30% dry mass) in the luminal crypts (cristae) helps to maintain a high K+ activity at the mucosal surface of the absorptive cells, apparently necessary for a K-linked absorption of nutrients and water. In the electrically isolated apical cavities of the midgut 'goblet' cells of Manduca sexta larvae, a similar matrix provides fixed counter anions for the electrogenically secreted K+, thus enabling the gut to sustain, in vivo, a transepithelial potential (TEPD) of some 150 mV (lumen + ve). This TEPD is used for maintaining a high pH of 11-12 in the midgut lumen. A similar mechanism of maintaining a high TEPD for sensory perception is suggested in insect sensilla and in vertebrate cochlea. A much lower concentration (10% dry mass) of the matrix in the apical invaginations (canaliculi) of Calliphora salivary glands facilitates a fluid secretion of isotonic KCl at high rates.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1985

Electron probe X-ray microanalysis of the effects of Bacillus thuringiensis var kurstaki crystal protein insecticide on ions in an electrogenic K+-transporting epithelium of the larval midgut in the lepidopteran, Manduca sexta, in vitro.

An alkaline hydrolysate of Bacillus thuringiensis var kurstaki HD1 (Btk) parasporal crystals was administered at 25 micrograms ml-1 (f.c.) to isolated, short-circuited, midguts of tobacco hornworm (Manduca sexta) larvae. The short-circuit current (s.c.c.), a precise measure of K+ active transport, was inhibited by 78% in 10 min in Btk-treated midguts as compared to controls. The elemental concentrations of K, together with Na, Mg, P, S, Cl and Ca, as well as the water content, were determined by electron probe X-ray microanalysis (EPXMA) in the muscle cells, columnar cells and goblet cells, as well as in the extracellular goblet cavity and the bathing media. The average K concentration in the goblet cell cavity was 129 mmol/kg wet wt in control midguts but only 37 mmol/kg wet wt in Btk-treated midguts. The elemental concentrations, including that of K, in other cell compartments were much less affected by Btk, but a rise in total cell calcium is suggested. It has been previously suggested that in vitro Btk acts specifically on limited regions of the apical membrane of the midgut epithelial cells. The simplest interpretation of the EPXMA results would be that initially Btk interacts specifically with the goblet cell apical membrane, which bounds the goblet cavity and contains the K+ pump responsible for the s.c.c. and high transepithelial potential difference (p.d.). Such interaction results in a rapid disruption of K+ transport across the goblet cell apical membrane, leading to dissipation of the K+ gradient and loss of p.d. The histopathological changes previously reported by other workers would then be a consequence of K+ pump inhibition causing changes in the intracellular pH, Ca2+ etc. Some possible molecular bases for these specific interactions between Btk and cell membrane are discussed.

Animals↗
PubMed1979

The quantitative measurement of electrolyte elements in nuclei of maturing erythrocytes of chick embryo using electron-probe X-ray microanalysis.

Na, K and Cl measurements have been made on frozen sections of chick red blood cells throughout embryonic development, using electron-probe microanalysis. There is an apparent fluctuation in the levels of these elements during maturation, although the Na/K ratio remains fairly constant. The nuclear Na concentration resembles that of the cytoplasm, rather than that of the medium, at all stages. Inhibitor studies indicate that when cytoplasmic Na, K and Cl levels are altered, their corresponding nuclear levels are similarly affected. Additionally, the measurements in nuclei isolated in anhydrous media from lyophilized cells have shown artefactual accumulation of high Na, K, Ca and Mg.

Animals↗
PubMed1979

Quantitative electron probe X-ray microanalysis of electrolyte elements within epithelial tissue compartments.

The electron probe X-ray microanalysis of 1-micron thick frozen-hydrated sections provides a method to measure local concentrations of electrolyte elements (and H2O) in and around the cells in situ with an analytical spatial resolution of better than 0.2 micron and a sensitivity limit better than 10 mM with a standard error of less than 10%. Our microprobe studies on several epithelia transporting isotonic fluids have provided strong evidence that the electrolyte concentration in the interspaces suspected to be the sites of solute-solvent coupling may, on average, be as much as 35% more than in the bathing fluid. There also appear to be distinct concentration gradients in interspaces, the profiles of which differ according to the tissue geometry but particularly according to the location of the leaky cell junctions, suggesting that the osmotic equilibration of the transported fluid may require substantial mass flow through the junctions. In addition, there is evidence a) that the major electrolytes in the cytoplasm of the epithelial cells are not uniformly distributed but may have distinct axial and radial concentration gradients that depend on active solute transport (e.g., that abolished by ouabain); b) that in some epithelia (e.g., rabbit ileum) there is a peripheral cytoplasmic zone that may support fast convective flow for transcellular fluxes; c) that the extracellular structures like the glycocalyx and basement membrane preferentially sequester potassium (and calcium) and could have a non-zero reflection coefficient; and d) that in normal cells, nuclei have ionic composition similar to that of the circumnuclear cytoplasm.

Animals↗