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Biomedical subjects

B Shukla

Publications and source records attributed to B Shukla.

At least 19 recordsLinked to original sources
PubMed2005

Mechanisms underlying the cardioprotective effect of L-cysteine.

In many tissues the availability of L-cysteine is a rate-limiting factor in glutathione production, though this has yet to be fully tested in heart. This study aimed to test the hypothesis that supplying hearts with 0.5 mM L-cysteine would preserve glutathione levels leading to an increased resistance to ischaemia reperfusion. Left ventricular function was measured in isolated perfused rat hearts before, during and after exposure to 45 min global normothermic ischaemia. Control hearts received Krebs throughout, whilst in treated hearts 0.5 mM L-cysteine was added to the perfusate 10 min before ischaemia, and was then present throughout ischaemia and for the first 10 min of reperfusion. Reperfusion injury was assessed from the appearance of lactate dehydrogenase (LDH) in the effluent. In two separate groups of control and treated hearts, ATP and glutathione (GSH) contents were measured at the beginning and end of ischaemia. Hearts treated with 0.5 mM L-cysteine showed a significantly higher recovery of rate pressure product (16,256+/- 1288 mmHg bpm vs. 10,324+/- 2102 mmHg bpm, p < 0.05) and a significantly lower release of LDH (0.54+/- 0.16 IU/g wet weight vs. 1.44+/- 0.31 IU/g wet weight, p < 0.05) compared to controls. Also, the L-cysteine treated group showed significantly better preservation of ATP and GSH during ischaemia in comparison to control. These results suggest that the mechanisms underlying the cardioprotective effects of 0.5 mM L-cysteine may include: increased anaerobic energy production either directly or through reduced degradation of adenine nucleotides; direct scavenging of free radicals; and/or improved antioxidant capacity through glutathione preservation.

Adenosine Triphosphate↗
PubMed2000

Analogue-resistant mutants of Azotobacter chroococcum derepressed for nitrogenase activity and early ammonia excretion having potential as inoculants for cereal crops.

Spontaneous mutants resistant to methionine sulfoximine (Msx), methyl alanine (Mal) and methyl ammonium chloride (Mac) were derived from A. chroococcum strain A103. Msx and Mal-resistant mutants expressed 1.73 to 10.98% of the fully derepressed nitrogenase activity when grown in Burk's medium containing ammonium acetate. Mac-resistant mutants did not express nitrogenase activity in ammonium acetate supplemented medium. The mutants excreted ammonia even after 2 days of growth and some mutants excreted more ammonia as compared to the parent. Selected mutants were inoculated on wheat (Triticum aestivum) and barley (Hordeum vulgare) under field conditions. Majority of the derepressed mutants increased grain yield of wheat and barley varying from 1.2 to 33.3%. However, host-dependent effects on grain yield were observed with different mutants. Two mutants, Mal 27 and Mac 19 showed significant increase in grain yields of both the crops. The results suggest that metabolic analogue-resistant mutants of Azotobacter have potential for use as a biofertilizer for cereal crops.

Alanine↗
PubMed1996

Diarrhoea associated with Candida spp.: incidence and seasonal variation.

To study the incidence and seasonal variation of diarrhoea associated with Candida, 978 diarrhoeal stool specimens from patients of all age groups were examined by microscopy and culture. Candida spp. was the sole pathogen (unassociated with other diarrhoeagenic bacteria, protozoa, or helminths) in 15.3% of the total cases. Candida albicans (94.9%) was the predominant species isolated. The incidence was highest among the infants aged 0-12 months (37.1%), followed by a decline in the rest of the children aged less than 5 years with a second peak in the people aged over 5 years, including adults. The paediatric age group had a significantly higher incidence in the summer season compared to the rainy (p < 0.05) or winter (p < 0.01) months. Thus, there was a definite age and seasonal variation in the incidence of diarrhoea caused by the overgrowth of Candida in the Varanasi region of the Indian subcontinent.

Adolescent↗
PubMed1993

Andrographolide protects rat hepatocytes against paracetamol-induced damage.

Andrographolide, the active constituent isolated from the plant Andrographis paniculata, showed a significant dose dependent (0.75-12 mg/kg p.o. x 7) protective activity against paracetamol-induced toxicity on ex vivo preparation of isolated rat hepatocytes. It significantly increased the percent viability of the hepatocytes as tested by trypan blue exclusion and oxygen uptake tests. It completely antagonized the toxic effects of paracetamol on certain enzymes (GOT, GPT and alkaline phosphatase) in serum as well as in isolated hepatic cells. Andrographolide was found to be more potent than silymarin, a standard hepatoprotective agent.

Acetaminophen↗
PubMed1993

Prevention of galactosamine-induced hepatic damage by picroliv: study on bile flow and isolated hepatocytes (ex vivo).

Picroliv, a standardized extract from the plant Picrorhiza kurrooa containing active constituents, showed a significant dose dependent (3-12 mg/kg p.o. x 7) protective activity against galactosamine-induced hepatic damage in rat as evaluated on the isolated hepatocytes (ex vivo) preparation. It markedly increased the percentage of viability of hepatocytes. It also restored the galactosamine-induced changes in the levels of enzymes (GOT, GPT and alkaline phosphatase) both in isolated hepatic cells as well as in serum. In addition, picroliv possessed a marked anticholestatic effect. Picroliv was found to be more potent than silymarin, a standard hepatoprotective agent.

Animals↗
PubMed1992

Choleretic effect of andrographolide in rats and guinea pigs.

Andrographolide from the herb Andrographis paniculata (whole plant) per se produces a significant dose (1.5-12 mg/kg) dependent choleretic effect (4.8-73%) as evidenced by increase in bile flow, bile salt, and bile acids in conscious rats and anaesthetized guinea pigs. The paracetamol induced decrease in volume and contents of bile was prevented significantly by andrographolide pretreatment. It was found to be more potent than silymarin, a clinically used hepatoprotective agent.

Animals↗
PubMed1991

Choleretic effect of picroliv, the hepatoprotective principle of Picrorhiza kurroa.

Picroliv, the hepatoprotective principle of the plant Picrorhiza kurroa, showed a dose-dependent (1.5-12 mg/kg x 7) choleretic effect in conscious rats and anaesthetised guinea pigs. It also possessed a marked anticholestatic effect against paracetamol- and ethynylestradiol-induced cholestasis. It antagonised the changes in bile volume as well as the contents (bile salts and bile acids). Silymarin, a known hepatoprotective agent, was tested simultaneously for comparison. Picroliv was found to be a more potent choleretic and anticholestatic agent than silymarin.

Acetaminophen↗