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Biomedical subjects

R K Goel

Publications and source records attributed to R K Goel.

At least 55 records · Page 3Linked to original sources

Neuropharmacological studies on Fusarium toxins--II: Total toxin extract from F. oxysporum.

The neuropharmacological activity profile of total fungal extract of F. oxysporum (FO) was investigated. FO enhanced spontaneous locomotor activity, exploratory behaviour and reduced pentobarbitone hypnosis. It had per se anticonvulsant action against maximal electroshock seizure (MES) and potentiated phenobarbitone and phenytoin in MES and also potentiated pentylenetetrazol (PTZ) convulsion. It antagonised morphine, tetrabenazine and haloperidol catalepsy. FO did not show per se analgesia or potentiation of morphine antinociception in mice, while both effects were present in rats. The effect of FO on body temperature was complex. It produced per se reduction in rectal temperature and potentiated the hypothermic responses of reserpine, apomorphine, PEA and I-dopa, and also the hyperthermic response of 5-HTP. The hyperthermic response of haloperidol was reversed by FO. It potentiated amphetamine and morphine lethality, amphetamine, PEA and apomorphine stereotypy, 5-HTP headtwitch response and post-swim grooming response. On swim-stress immobility, while the time of onset of immobility was reduced, FO did not modify the duration of immobility. On foot-shock induced aggression in paired rats, FO produced a decrease in the latency to onset of fighting behaviour and increased the total contact period and the cumulative aggressive score. FO potentiated clonidine automutilation. It has, thus, facilitated aggressive behaviour. The effects are likely to be due to the presence of fusaric acid in FO, which inhibits dopamine beta-hydroxylase and is known to have dopaminergic effects. This investigation has practical implications. since F. oxysporum is a common food contaminant.

Analgesics↗

Pharmacological actions of Pongamia pinnata seeds--a preliminary study.

Direct ethanolic and sequential petroleum ether, chloroform, acetone and ethanolic extracts (50-100 mg/kg, i.p.) of P. pinnata seeds given 30-60 min before revealed anti-inflammatory, analgesic and anti-ulcerogenic activities in rats. The activities were present maximum in petroleum ether and chloroform extracts. However, the extracts also showed shortening of pentobarbitone induced 'sleep time' in rats.

Analgesia↗

Concurrent evaluation of immunization programme by Lot Quality Assurance Sampling.

The current EPI methodology for identifying immunization coverage is simple and easy to carry out under field conditions and gives a good idea about immunization coverage. However, it is not useful for local managers. It does not identify small health units with poor performance. Information on performance at the local level is vital to enhance overall immunization coverage. Estimation of coverage on a small area basis can be made by Lot Quality Assurance Sampling (LQAS). LQAS was used in nine sub-centres of district Saharanpur. The methodology was found to be feasible and identified seven sub-centres with poor current performance. Although LQAS may not be a good substitute for current EPI methodology to evaluate immunization coverage in a large administrative area, it is suggested that LQAS is a useful additional method for routine monitoring and evaluation of health programmes on a small area basis, especially as the overall coverage increases.

Communicable Disease Control↗

Effect of lignocaine on eicosanoid synthesis by pieces of human gastric mucosa.

Lignocaine can affect prostaglandin synthesis in various tissues, and it has anti-inflammatory activity. No studies have been made previously on human isolated gut tissues. When concentrations of 5, 50 and 250 micrograms mL-1 lignocaine were incubated with human gastric mucosa/submucosa at 37 degrees C for 30 min, only the highest concentration reduced the levels of prostaglandin E, thromboxane B2 and 6-keto-PGF1 alpha in the incubates, and leukotriene C4/D4 was unaffected. Therapeutically relevant amounts of lignocaine given parenterally would therefore seem unlikely to alter gastric mucosal prostanoids, but high doses can be given orally because of extensive first-pass metabolism in the liver.

6-Ketoprostaglandin F1 alpha↗

Effect of Tamrabhasma, an Indian indigenous preparation of copper, on rat gastric mucosal resistance.

Tamrabhasma (TMB), an Indian indigenous preparation of copper, was studied for its effects on factors related to rat gastric mucosal resistance. Rats of either sex treated with TMB (2.5 mg/kg po, twice daily for 3 days) showed (i) increased mucosal sialomucin and fucose contents; (ii) decreased gastric juice DNA and protein; and (iii) no change in DNA and the incorporation of [3H]-thymidine in to mucosal cell DNA. aspirin treatment decreased both the sialomucin and fucose contents, and increased DNA and incorporation of [3H]-thymidine in to mucosal cell DNA. However, aspirin increased gastric juice DNA and protein contents. Since gastric juice DNA and the incorporation of [3H]-thymidine into mucosal cell DNA indicate the rate of mucosal shedding and cell proliferation, the results indicate ways in which TMB may increase gastric mucosal resistance to damage.

Animals↗

Effects of cupric chloride and tamrabhasma, a traditional Indian preparation of copper, on eicosanoid production by human gastric and colonic mucosa.

Tamrabhasma is a traditional copper oxide-containing Indian preparation which has anti-ulcer activity. We have studied the effect of tamrabhasma and CuCl2.2H2O on prostaglandin formation by human gastric and colonic mucosa and submucosa, as prostaglandins have mucosal protective activity, and their release may contribute to the anti-ulcer effect. With the gastric mucosa, tamrabhasma 10 micrograms mL-1, but not 0.1 or 1 microgram mL-1, increased prostaglandin E (PGE) concentration by 38% (P < 0.05), with little or no effect on 6-keto-PGF1 alpha, thromboxane B2 or the leukotriene (LT) LTC4/LTD4. CuCl2.2H2O (10 micrograms mL-1) increased 6-keto-PGF1 alpha by 46% (P < 0.05), but 0.1, 1, 50 and 250 micrograms mL-1 did not significantly affect any of the prostanoids, and only the highest concentration reduced the amount of LTC4/LTD4. In the colon mucosa, tamrabhasma (0.1-10 micrograms mL-1) or CuCl2.2H2O (10-50 micrograms mL-1) increased all the prostanoids and this effect was greater than in the gastric mucosa but there was no significant change in LTC4/LTD4. CuCl2.2H2O showed a bell-shaped concentration-effect curve, with no significant effect at lower and higher amounts. Indomethacin (0.1-10 micrograms mL-1) caused a concentration-dependent reduction in the prostanoid amounts. The effect of tamrabhasma was probably not only due to the presence of Cu2+, as tamrabhasma was more effective than CuCl2.2H2O alone; in addition the solubility of CuO is very low. Increased prostanoid levels might explain, at least partly, the gastric mucosal protection by tamrabhasma. The results in the colon, however, raise the possibility that tamrabhasma should be examined for the treatment of inflammatory bowel disease.

Anti-Ulcer Agents↗

Potentiation of gastric toxicity of ibuprofen by paracetamol in the rat.

A fixed dose combination of ibuprofen (400 mg) and paracetamol (325 mg) is by far the most extensively prescribed medicament for a variety of musculoskeletal disorders in India. Following clinical observations that this drug combination induces significant adverse effects, its gastric toxicity was investigated in rats. Ibuprofen (25 mg kg-1 p.o., twice daily x 5 days), paracetamol (20 mg kg-1 p.o, twice daily x 5 days), and a combination of the two, had no significant effect on free and total gastric acidity in pylorus-ligated rats. Ibuprofen induced visible gastric ulceration whereas paracetamol did not. However, the combination of these two drugs had an additive effect inducing severe gastric erosions, ulcerations and bleeding. The augmented toxicity of this drug combination appeared to be a consequence of attenuated gastric mucin activity and reduction in the gastric muco-protective barrier. This investigation indicates the likely hazard of an irrational fixed dose drug combination.

Acetaminophen↗

Antiulcerogenic and anti-inflammatory effects of emodin, isolated from Rhamnus triquerta wall.

Emodin, an anthraquinone derivative, isolated from the whole plant of R. triquerta, in 15 mg/kg dose (ip) exhibited anti-inflammatory activity against carrageenin-induced pedal inflammation in rats. In the same dosage it also showed antiulcer activity against 4 hr pylorus-ligated, aspirin and immobilization stress-induced gastric ulcers in rats. It decreased acid and pepsin output and augmented mucus secretion in terms of total carbohydrate: protein ratio in the gastric juice of aspirin treated pylorus-ligated rats, indicating that the antiulcerogenic effect of emodin may be due to its effect on gastric secretion.

Animals↗

Antiulcerogenic and antiinflammatory studies with shilajit.

In folk medicine, shilajit has been used to treat diverse clinical conditions ranging from peptic ulcer to bone healing. The present study was conducted to evaluate the possible antiulcerogenic and antiinflammatory activities of shilajit obtained from the rocky mountains of Zarlek, Badekshan, Afghanistan. Shilajit increased the carbohydrate/protein ratio and decreased gastric ulcer index, indicating an increased mucus barrier. Shilajit was found to have significant antiinflammatory effect in carrageenan-induced acute pedal oedema, granuloma pouch and adjuvant-induced arthritis in rats. The results of the present study thus substantiate the use of shilajit in peptic ulcer and inflammation.

Animals↗

Effect of ethanol on eicosanoid synthesis by human gastric and colonic mucosal pieces.

1. Human gastric and colonic mucosa obtained at operation was cut into small pieces and incubated with different concentrations of ethanol. 2. Ethanol (5-40%) caused a concentration-dependent increase in the amounts of prostaglandin E (PGE), thromboxane B2 (TXB2), 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) and (up to 20% ethanol) leukotriene C4/D4 (LTC4/D4) in incubates of mucosal pieces from either region. 3. Higher concentrations of ethanol usually caused small increases or reductions of eicosanoid levels; gastric mucosal PGE and 6-keto-PGF1 alpha were still increased by 100% ethanol, whereas TXB2 was unaltered, and LTC4/D4 was reduced. With the colonic mucosa, 100% ethanol increased PGE but reduced the other eicosanoids. 4. Gastric mucosal pieces incubated in water or phosphate buffer yielded generally similar amounts of eicosanoids. However, colonic mucosa yielded more when incubated in water, possibly indicating a greater sensitivity to osmotic damage. This difference between the two regions is consistent with the ability of the gastric mucosa to resist damage by water on its epithelial surface.

6-Ketoprostaglandin F1 alpha↗

Effect of piracetam, a nootropic agent, on experimental gastric ulcers in rat.

Piracetam, used clinically for cognitive disorders, was found to have significant anti-ulcerogenic activity against immobilization stress- and aspirin-induced gastric ulcers in rats. The anti-ulcer effect of piracetam was exerted by augmentation of mucosal resistance. This was indicated by the significant attenuation of the decrease in total carbohydrate: protein ratio induced by aspirin. It also reversed the marked increase in gastric juice protein and DNA induced by aspirin, indicating that piracetam attenuated the augmented mucosal cell exfoliation induced by the ulcerogen. The drug also increased gastric mucosal serotonin concentrations. Piracetam, thus appears to have a profile of activity associated with cytoprotective agents.

Animals↗

Stimulation of gastric and colonic mucosal eicosanoid synthesis by plantain banana.

Extracts of plantain banana (Musa sapientum Linn var. paradisiaca) were studied on the accumulation of eicosanoids in incubates of human gastric and colonic mucosa. The ethanolic extract caused a concentration-dependent increase in the eicosanoid accumulation but the water extract was ineffective. Since all the eicosanoids studied tended to increase, banana may act by increasing the availability of arachidonate. In control tissues the accumulation of PGE and TXB2 in the incubates decreased with time while that of 6-keto-PGF1 alpha increased (colon only, studied).

Eicosanoids↗

Effect of lapachol, a naphthaquinone isolated from Tectona grandis, on experimental peptic ulcer and gastric secretion.

Lapachol, a naphthaquinone isolated from the roots of Tectona grandis given at a dose of 5 mg kg-1 p.o. twice daily for 3 days was found to have an anti-ulcerogenic effect on subsequently induced experimental gastric and duodenal ulcers in rats and guinea-pigs. Its action appears to be associated with an effect on the protein content of gastric juice, and it reversed aspirin-induced changes in peptic activity, protein and sialic acid.

Animals↗