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Biomedical subjects

S Chandra

Publications and source records attributed to S Chandra.

At least 19 recordsLinked to original sources
PubMed1992

The in vivo inhibition of transport enzyme activities by chloroquine in different organs of rat is reversible.

The antimalarial drug chloroquine is found to inhibit Na+, K(+)-ATPase, Ca2+, Mg(2+)-ATPase, Ca(2+)-ATPase, pNPPase and acetylcholinesterase activities in different organs of rat in vivo when injected for a certain periods of time. The inhibition seems to be due to the changes in the level of phospholipid, cholesterol and the fatty acid of the lipid and the alteration of the fluidity of the microsomal membranes. However, the enzyme activities return to the normal level in about 2-3 weeks after the discontinuation of the drug suggesting that the drug effect is reversible.

4-Nitrophenylphosphatase↗
PubMed1992

Nail-patella syndrome in a spontaneously aborted 18-week fetus: ultrastructural and immunofluorescent study of the kidneys.

Nail-patella syndrome (NPS), hereditary onycho-osteodysplasia, is an autosomal dominant disorder of nail dystrophy, patellar absence or hypoplasia, incomplete elbow extension, conical posterior iliac horns, and nephropathy. We studied the kidneys of an 18-week spontaneously aborted fetus of a mother with the NPS. Ultrastructural examination of the kidney showed thickening of the capillary walls of the glomeruli and mesangium. There was irregular thickening of basement membranes with subendothelial fibrillar electron-dense deposits. Immunofluorescence showed fibrinogen deposition in glomerular basement membranes. Fibrinogen deposition in utero may ultimately lead to glomerular fibrosis and intrabasement membrane collagen deposition as seen in the adult renal lesion of this syndrome. This is the first report of the NPS in which the renal abnormalities have been studied in a fetus. These findings provide support for possible prenatal diagnosis of NPS by intra-uterine kidney biopsy.

Abortion, Spontaneous↗
PubMed1992

Purification and characterization of wheat and pine small basic protein substrates for plant calcium-dependent protein kinase.

A wheat basic protein (WBP) was purified to homogeneity from wheat germ by a protocol involving extraction, centrifugation, batchwise elution from carboxymethylcellulose (CM-52), acidification with trifluoroacetic acid, neutralization and HPLC on a SP5PW cation exchange column. WBP is a 10 kDa protein and is phosphorylated on serine residues by wheat germ Ca(2+)-dependent protein kinase (CDPK). [32P]phosphoWBP exactly comigrates with WBP on SDS-PAGE. WBP does not inhibit either wheat germ CDPK or calmodulin-dependent myosin light chain kinase. Apart from histone H1, WBP is the best endogenous substrate yet found for wheat embryo CDPK. A 12 kDa pine basic protein (PBP) was purified to homogeneity from seeds of stone pine (Pinus pinea L.) by a simple procedure involving batchwise elution from carboxymethylcellulose and cation exchange HPLC. PBP is also a good substrate for CDPK and is phosphorylated on Ser residues. N-terminal sequencing of WBP and PBP revealed that these proteins are homologous to a family of small basic plant proteins having a phospholipid transfer function.

Amino Acid Sequence↗
PubMed1992

Host resistance assays as predictive models in styrene immunomodulation.

Three infection models namely an oncogenic virus Encephalomyocarditis (EMCV), a rodent strain of malaria, Plasmodium berghei, and a rodent hookworm parasite, Nippostrongylus brasiliensis, were used to confirm the in vivo immunotoxic potential of styrene reported in our previous communication. The altered host resistance to these challenge infections was evaluated in rodents pre-treated with 0, 0.02, 0.03 or 0.05 x LD50 dose of styrene (5 days/week) for 4 weeks. Significantly increased mortality in mice was observed at the various tested dose levels of styrene when challenged with EMCV. Similarly the results obtained in the malaria infection model indicated increased blood parasitaemia as well as significantly enhanced mortality in styrene-treated animals. Also the rejection of N. brasiliensis was also found to be significantly impaired in animals treated with a higher dose of styrene. These results indicate that the exposure of rodents to styrene can markedly impair host resistance which may have biological significance.

Adjuvants, Immunologic↗
PubMed1992

Sample preparation of animal tissues and cell cultures for secondary ion mass spectrometry (SIMS) microscopy.

Sample preparation is a critical step in the elemental analysis of animal tissues and cell cultures with ion microscopy. Since live cells cannot be analyzed with ion microscopy, a careful sample fixation is necessary which preserves the native structural and chemical integrity of a specimen. The evaluation of morphological and chemical integrity of a fixed specimen is necessary before any physiological explanation of ion fluxes is interpreted based on ion microscopy. For diffusible ion localization studies, strict cryogenic procedures are recommended. Examples are shown for diffusible ion microanalysis in frozen-freeze-dried tissues and cell cultures. Ion microscopy studies of tightly bound elements/molecules may be conducted in chemically fixed and/or plastic embedded specimens. Since it is not generally known which elements/molecules are tightly bound to the tissue matrix, a confirmation of elemental distribution with cryogenic procedures is desirable. A recent approach of combining laser scanning confocal fluorescence microscopy and ion microscopy on the same frozen freeze-dried cell is also discussed for recognizing smaller cytoplasmic structures in ion microscopy images.

Animals↗
PubMed1992

Subcellular imaging of calcium exchange in cultured cells with ion microscopy.

Calcium to calcium exchange between intracellular and extracellular pools has been imaged directly in individual cells using stable 44Ca (98.78% enrichment) in the nutrient medium and an isotopic imaging technique, ion microscopy. Observations were made by imaging mass 40 to determine the native intracellular calcium (40Ca), and mass 44 to localize the 44Ca from the extracellular medium that exchanged with cellular calcium. LLC-PK1 porcine kidney epithelial cells were exposed to the nutrient medium with 1.87 mM stable 44Ca for 0, 1, 2, 5, 8, 20, 60 and 90 min, and cryogenically prepared prior to ion microscopic analysis. The cell nucleus, the Golgi region and the remaining cell cytoplasm could be spatially resolved to within about 0.5 microns using the ion microscope. On the basis of the kinetics of 40Ca to 44Ca exchange it was observed that all three compartments had a rapidly exchanging pool of calcium, which took about 2 min to exchange. A moderately rapidly exchanging pool of calcium was identified between 2 and 20 min of calcium exchange. The cells had exchanged about 50% of their total internal calcium with the external calcium in less than 20 min. The remaining 50% of the cellular calcium could be classified as a slowly exchanging pool. Isotopic images of 39K and 23Na were recorded along with 40Ca and 44Ca images to assess the health status of the cell. Isotopic imaging has the unique ability to distinguish intracellular calcium from the extracellular calcium that enters cells and has enormous potential for studies of calcium transport under physiological and pathological conditions.

Animals↗
PubMed1992

Therapeutic and diagnostic role of bronchoscopy in pediatric age group.

Two hundred and seventy five cases were evaluated bronchoscopically for various respiratory conditions. In 140 cases, a foreign body and in 30 cases mucus plug was removed. In 47 cases there was inflammation of the tracheobronchial tree. Forty patients with empyema thoracis were evaluated bronchoscopically because of persistence of bronchopleural fistula or continued pus discharge from intercostal tubes not responding to the routine treatment. The purpose of the article is to stress the therapeutic as well as diagnostic aspect of bronchoscopy for various respiratory conditions in pediatric age group.

Bronchoscopy↗
PubMed1991

Imaging acetylcholine-receptor-induced influx of inorganic ions at single-cell resolution with ion microscopy.

Ion microscopy was used to image neurotransmitter-induced tracer ion flux at single-cell resolution. A mammalian muscle cell line (BC3H1) expressing the nicotinic acetylcholine receptor was exposed to 2 mM CsCl, with and without the acetylcholine analog carbamylcholine. 133Cs+, 12C+, 40Ca+, 39K+, and 23Na+ secondary ion images revealing intracellular distribution of these elements were recorded with a CAMECA IMS-3f ion microscope from freeze-fractured freeze-dried BC3H1 cells. The ion images were digitized directly from the microchannel plate/fluorescent screen detector assembly of the ion microscope using a charge-coupled device imager. Submillimolar concentrations of cesium were easily imaged. Cesium images were normalized to carbon images for a direct comparison of carbamylcholine-exposed and control cells. Carbamylcholine-exposed cells showed significantly higher cesium influx than controls. Within the carbamylcholine-exposed cells, cell-to-cell heterogeneity for cesium influx was observed. Injured cells were identified by their potassium, sodium, and calcium signals and omitted from the quantitative analysis of the ion image data. This method should be useful for identifying cells from various regions of the nervous system containing receptors that control the translocation of monovalent cations, including Cs+. Among these neuronal receptors in the central nervous system are those activated by acetylcholine, glutamate, aspartate, or N-methyl-D-aspartate.

Carbon↗
PubMed1991

Congenital esophageal obstruction by intraluminal mucosal diaphragm.

Congenital intraluminal esophageal diaphragm causing complete obstruction is a rare anomaly. By esophagoscopy, a complete membranous diaphragm was demonstrated, perforated, and excised. In the English language literature, this case represents the first report of an isolated membranous atresia at the lower end of the esophagus. A brief review of the world literature and the classification of membranous atresia of the esophagus is discussed.

Bronchopneumonia↗
PubMed1991

Hazards of mattresses, beds and bedding in deaths of infants.

Of 52 infants who had died suddenly and were referred to autopsy, nine had lain on adult water beds for the first time; five had died as a result of accidents; two had died on water beds; two were in beds with widely spaced slats; and one had died as a result of strangulation. Three deaths were due to overlying. Three other infants had been placed on sheepskin rugs for the first time and were found dead shortly thereafter. These infants ranged in age from 2 to 9 months, except for a severely mentally retarded nine-year-old with spastic paraplegia. We believe that a general warning should be issued concerning water beds and that soft bedding should not be used for infants. Infants should not be placed unattended or left to sleep on water beds; only beds recommended for infants should be used. Overlying of a young infant is most likely to occur on a water bed, or if the parent is obese or has consumed alcohol.

Accidents↗
PubMed1991

Cytotoxicity of eugenol in sealer containing zinc-oxide.

In this study two zinc-oxide-based root canal sealers were compared for their tissue toxic response. The sealers tested were zinc-oxide eugenol and zinc-oxide glycerine. Fifteen albino rats were used for the study and were injected subcutaneously in the preset state. The tissue response was assessed by counting the polymorphonuclear cells at Day 1, Day 7 and Day 15 of the study period. The inflammatory response was graded according to the mean polymorphonuclear counts in the five rats for each period. The results showed that the toxicity was greater for the eugenol-containing sealer and increased during the three time intervals. For the non-eugenol sealer the response was milder and reached a peak by 7 days after which it decreased.

Animals↗
PubMed1991

Calcium sequestration in the Golgi apparatus of cultured mammalian cells revealed by laser scanning confocal microscopy and ion microscopy.

Co-localization of the elements calcium, potassium, sodium and magnesium with sequestering organelles has been achieved by application of two microscopy techniques on the same cell. Organelles were first localized by laser scanning confocal microscopy (LSCFM) using fluorescent organelle stains. The same cells were then analyzed for elemental distribution with ion microscopy. This approach has identified a perinuclear region of prominent total calcium concentration with the Golgi apparatus. Live cells were fluorescently stained with C6-NBD-ceramide for labeling the Golgi apparatus prior to cryogenic preparation and freeze-drying, and imaged with LSCFM for Golgi localization; identical cells were then analyzed with ion microscopy to image subcellular distributions of total calcium, potassium, sodium and magnesium. In three cell lines, LLC-PK1 porcine kidney epithelial cells, Swiss 3T3 mouse fibroblast cells and L5 rat myoblast cells, the Golgi regions contained significantly higher total calcium concentrations than any other region of the cell (as measured at the spatial resolution of ion microscopy of about 0.5 micron). Intracellular potassium, sodium and magnesium were homogeneously distributed throughout the cell and did not show this pattern. Measurements of depletion of calcium by exposure to calcium-free medium showed that the Golgi apparatus was substantially more resistant to calcium depletion than all other regions of these cells, but sequestered Ca2+ could be released from the Golgi by exposing the cells to calcium ionophore A23187. The Golgi apparatus appears to sequester about 5% of the total cell calcium in LLC-PK1 cells, about 2.5% in 3T3 cells and L5 cells.

4-Chloro-7-nitrobenzofurazan↗
PubMed1991

The in vivo inhibition of transport enzyme activities in different organs of rat by chlorpromazine is reversible.

Chlorpromazine, an antipsychotic drug is found to inhibit Na+K(+)-ATPase, Ca(2+)-ATPase and acetylcholinesterase activities in the microsomal membranes of rat in vivo, when the drug is injected for certain periods of time. The inhibition seems to be due to the changes in fatty acid composition of lipid and microviscosity of the membranes. However, once the drug has been withdrawn, the enzyme activities are found to return to the normal level in three to five weeks, suggesting that the drug effect is reversible.

Acetylcholinesterase↗