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Biomedical subjects

S Das Gupta

Publications and source records attributed to S Das Gupta.

At least 37 records · Page 2Linked to original sources

Combined exposure to lead and ethanol on tissue concentration of essential metals and some biochemical indices in rat.

The effect of daily oral administration of ethanol (2.5, 5, or 10% in drinking water for 8 wk), lead (10 mg/kg, po, once daily for 8 wk), or their combination on tissue trace-metal concentration and hematopoietic and hepatic biochemical indices was investigated in male rats. Ethanol (10%) ingestion enhanced the hepatic lipid peroxidation and decreased the calcium and magnesium content of blood and liver. Coexposure to lead and ethanol (5 and 10%) produced a more pronounced elevation of blood zinc protoporphyrin (ZPP) and hepatic lipid peroxidation. Combined lead-ethanol exposure also lowered the concentration of blood and hepatic magnesium and calcium and increased the amount of lead in the blood, liver, and brain compared to a group treated with lead alone. The results suggest that chronic alcohol ingestion results in calcium and magnesium loss. However, coexposure to lead and ethanol could result in more serious depletion of calcium and magnesium, and this could be the cause of suspected synergism between alcohol consumption and lead poisoning.

5-Aminolevulinate Synthetase↗

A cloned kinetoplast DNA mini-circle fragment from a Leishmania spp. specific for post-kala-azar dermal leishmaniasis strains.

DNA-DNA hybridization techniques have been found to be very useful in the classification and identification of Leishmania parasites. We report here the cloning of a mini-circle from Leishmania strain UR6 in a plasmid and subcloning of the mini-circle fragments in M13 mp9. Clone MLURk32, containing a 560 bp fragment of mini-circle, has been found to have unique specificity. Application of this specific probe in identifying different Leishmania isolates reveals that the probe reacted only with strains of post-kala-azar dermal leishmaniasis but not with strains or isolates of visceral leishmaniasis.

Animals↗

Interaction of zinc, methionine or their combination with lead at gastrointestinal or post-absorptive level in rats.

The ability of zinc, methionine or their combination given by gavage to prevent or treat experimental oral lead intoxication in rats was investigated. Simultaneous oral supplementation with zinc plus methionine was found to be most effective in reducing lead induced inhibition of delta-aminolevulinic acid dehydratase (ALAD) activity in blood, elevation of urinary delta-aminolevulinic acid (ALA) excretion and in enhancing the hepatic glutathione (GSH) contents. The combination was also most effective in reducing the accumulation of lead in blood, liver and kidney compared to zinc or methionine alone. Prevention was more effective than treatment after lead exposure which may be caused by a decrease in the absorption of lead in the gastrointestinal tract in the presence of zinc and/or methionine.

Animals↗

Actions and interactions of cholinolytics and cholinesterase reactivators in the treatment of acute organophosphorus toxicity.

Different drug combinations consisting of cholinolytic and a cholinesterase (ChE) reactivator provide greater therapeutic efficacy in acute organophosphorus (OP) poisoning in mice than when used alone. Maximum protection, as determined by a shift of the LD50 for the two OP agents, was observed with the cholinolytic benactyzine. A protection index (P.I.) of 42 was obtained when benactyzine was given along with obidoxime in diisopropylphosphorofluoridate (DFP) intoxication. With the more toxic OP agent soman (o-pinacolylmethylphosphonofluoridate), the same cholinolytic only offered a maximum P.I. of 3.2 when administered with HS-6, another bispyridinium ChE reactivator. This beneficial effect of benactyzine is possibly due to its greater antimuscarinic effect in the central nervous system than atropine or dexetimide.

Acute Disease↗

Interaction of reversible and irreversible cholinesterase inhibitors on the monosynaptic reflex in neonatal rats.

The ability of physostigmine (PHY) and pyridostigmine (PYR) to protect against the segmental synaptic depression caused by sarin was examined in isolated spinal cords from neonatal rats. The monosynaptic reflex was unaffected at concentrations up to 0.1 microM PHY or 0.3 microM PYR but raising the concentrations of either drug produced a concentration-dependent depression of the monosynaptic reflex which could be completely antagonized by atropine. The monosynaptic reflex was depressed by 50% at 0.45 microM PHY and 2 microM PYR with maximal depression occurring at 1 microM PHY (to about 10% of control) and 10 microM PYR (to about 35% of control). Pretreating the cords with 0.1 microM PHY and PYR for 30 min failed to protect against the depressant effects of sarin even though they inhibited total cholinesterase (ChE) by 27 and 21%, respectively. Both PHY and PYR depressed total ChE activity of the spinal cord in a concentration-dependent manner with 50% inhibition of ChE occurring at 0.8 microM. These results suggest that the carbamates affect segmental transmission by activation of a muscarinic receptor, that protective carbamylation of ChE is ineffective against organophosphorus-induced segmental depression, and that inhibition of ChE is unrelated to both carbamate- and organophosphorus-induced depression of the monosynaptic reflex.

Animals↗

Organization and size class homogeneity of ribosomal RNA genes of catfish Heteropneustes fossilis.

The ribosomal RNA genes of catfish Heteropneustes fossilis Bloch were examined by Southern blot analysis of genomic DNA digested with restriction enzymes and probed with labelled catfish ribosomal RNA. The major repeat length is 12 kb and about 300 copies per haploid genome are tandemly arranged. The repeat lengths are homogeneous in size in different tissues and individuals. A restriction site polymorphism exists in some of the repeats.

Animals↗

Segmental synaptic depression caused by diisopropylphosphorofluoridate and sarin is reversed by thyrotropin-releasing hormone in the neonatal rat spinal cord.

The organophosphorus compounds diisopropylphosphorofluoridate (DFP) and isopropylmethylphosphonofluoridate (sarin) depressed the monosynaptic reflex (MSR) in spinal cords from 7- to 9-day-old male rats. The concentrations of DFP and sarin which depressed the MSR by nearly 50% were 100 microM and 100 nM, respectively. Simultaneous superfusion of the cords with thyrotropin-releasing hormone (TRH) with either DFP or sarin resulted in a reversal of the depression. The depression caused by DFP was reversed to 95% of control by 100 nM TRH whereas similar reversal of sarin-induced depression required a 10-fold greater concentration of TRH. The potentiating effect of TRH was not affected by atropine even at a high concentration (1 microM) although atropine easily reversed organophosphorus-induced depression of the MSR. It appears that reversal of organophosphorus-induced depression by TRH might occur through a noncholinergic, TRH-sensitive receptor mechanism and may be unrelated to acetylcholinesterase activity. This action represents a possible utility of TRH as an adjunct in organophosphorus toxicity.

Animals↗

Pharmacokinetics of pralidoxime chloride and its correlation to therapeutic efficacy against diisopropyl fluorophosphate intoxication in rats.

A two compartment system is used to study the therapeutic efficacy of pralidoxime chloride (1) along with a suitable pretreatment against diisopropyl fluorophosphate (2) intoxication in rats. The data were analyzed by standard techniques. Though thiamine hydrochloride pretreatment prolonged the biological half-life of 1 but it failed to increase the protective efficacy of 1, on the other hand sodium hydrogen carbonate pretreatment augmented the protective action of 1 without altering its biological half-life appreciably, through increased distribution of 1 into tissue compartment.

Animals↗

Studies on the efficacy of diethyxime as an antidote against organophosphorus intoxication in rats.

Diethyxime, a non-quaternary cholinesterase reactivator was evaluated for its antidotal efficacy against organophosphorus intoxication in rats using the protection index, cholinesterase reactivation and neuromuscular function as the experimental protocol. Diethyxime along with atropine produced a marked antidotal effect against dimethyl dichlorovinyl phosphate (DDVP) poisoning on all the parameters studied. The action of diethyxime was mainly peripheral. The protective efficacy against diisopropyl fluorophosphate (DFP) poisoning was not observed with this reactivator.

Animals↗

[Etiology, prognosis and therapy of frostbite].

Frostbite is a serious illness with potentially disastrous consequences. The authors present a review of its pathophysiology, classification, prognosis and treatment under the special aspect of armed forces operating in subzero regions.

Animals↗