Biomedical subjects

P L Sharma

Publications and source records attributed to P L Sharma.

At least 19 recordsLinked to original sources

PubMed1995

Evaluation of antimuscarinic activity in human volunteers: a teaching aid in clinical pharmacology.

The antimuscarinic activity of oxyphenonium bromide, diphenhydramine hydrochloride and astemizole were evaluated in six volunteers. The parameters used were salivary secretion, heart rate and pupillary size. The results indicated that the changes in heart rate and pupillary size and measurements were not convenient parameters for class room demonstration. However, salivary secretion and dryness of mouth were found to be reliable parameters for measurement. It was concluded that simple procedures like evaluation of antimuscarinic activity could be introduced as teaching aids in clinical pharmacology for undergraduate students.

Adult↗

PubMed1994

Possible mechanism of endosulfan-induced enhancement of memory acquisition and retention in mice.

The effects of pre-training and post-training administration of endosulfan on retention of a step-down passive avoidance task was studied in mice. Endosulfan at doses of 1.0 mg/kg(ip) and 2.0 mg/kg(ip) enhanced memory acquisition and retention. This effect of endosulfan was possibly mediated by interaction with cholinergic neurotransmission, as scopolamine (0.5 mg/kg, ip) significantly antagonized the memory enhancing effects of endosulfan. Clonidine (0.05 mg/kg, ip) did not have any effect on enhancement of memory produced by endosulfan, thus indicating possibly no role of noradrenergic system.

Animals↗

PubMed1993

Clinical evaluation of the effect of omeprazole, cimetidine, famotidine and ranitidine on histamine induced cutaneous wheal and flare response.

The effect of H2 receptor antagonists on immediate cutaneous response to allergens remain controversial. In the present study, the effect of 7-day administration of omeprazole, cimetidine, famotidine and ranitidine on histamine induced wheal and flare reaction was evaluated. A single blind randomized parallel group study with within patient comparison of responses was planned in non-ulcer dyspepsia patients eligible to receive H2 antagonists or omeprazole. None of the drugs produced any changes in the area of the wheal in comparison to respective baseline values. The area of flare was decreased by all the drugs and the percentage decrease in this parameter caused by omeprazole, cimetidine, famotidine and ranitidine was 2.4, 12.3, 20.2 and 13.2, respectively. Only famotidine caused a significant decrease in flare area (p < 0.05).

Adult↗

PubMed1992

Effect of peripheral administration of cinnarizine and verapamil on the abstinence syndrome in diazepam-dependent rats.

The effects of two calcium channel blockers (verapamil and cinnarizine) were evaluated on diazepam withdrawal symptoms. Rats were made diazepam dependent by chronic treatment with daily injections of the drug, 20 mg/kg IP for 3 weeks. On abrupt termination of the drug, animals showed withdrawal hyperactivity that was assessed by autonomic, behavioural and motor signs. The peak effect was seen 3 days after the withdrawal of diazepam. On IP administration, verapamil and cinnarizine (10, 20 and 40 mg/kg) given on eight occasions at an interval of 12 h reversed the withdrawal-induced increase in spontaneous motor activity. Cinnarizine in higher doses (20 and 40 mg/kg) was found to be effective in suppressing the behavioural signs but verapamil did not show any protective effect against startle response and irritability. These results suggest that modulation of the calcium influx in the CNS might influence withdrawal.

Animals↗

PubMed1992

Development of antiviral treatment strategies in murine models.

Murine models with type C murine leukemia viruses have been used to develop major new prophylactic and therapeutic strategies in vaccination, drug therapy of acute virus exposure and chronic viremia, combination therapy, prevention of maternal transmission, and therapy targeted to the central nervous system. Transgenic mice expressing either the whole human immunodeficiency virus type 1 (HIV-1) provirus or subgenomic sequences allow the in vivo analysis of selected HIV-1 functions. The full replicative cycle of HIV-1 can be studied in human/mouse chimerae which were created by transplanting human hematolymphoid cells into SCID mice. The chimeric SCID mouse models have been used successfully to evaluate anti-HIV-1 drugs. The role of the various murine retrovirus systems in the development of anti-HIV-1 and anti-AIDS therapies is summarized.

Animals↗

PubMed1992

MK-801 antagonizes the lethal action of centrally and peripherally administered cypermethrin in mice and rats.

The present study investigated the effect of MK-801, an N-methyl-D-aspartate antagonist, on the convulsant lethal action of cypermethrin administered centrally or peripherally. Cypermethrin produced severe convulsions and death in a dose-dependent manner. MK-801 (0.5, 1 and 2 mg kg-1, intraperitoneally) significantly increased the onset time of convulsions and decreased the mortality in the peripherally treated cypermethrin group. MK-801 (1.0 and 2.0 mg kg-1) attenuated the convulsant action of cypermethrin (50 micrograms, intracerebroventricularly) significantly. Survival rate was also increased significantly. However, MK-801 (0.5 mg kg-1) did not produce any significant protective effect against centrally administered cypermethrin. These results suggest excitatory amino acids to be a target for pyrethroid-induced neurotoxicity.

Animals↗

PubMed1992

Drug interaction between rifampicin, isoniazid and cotrimoxazole in rabbits.

1 The results of cotrimoxazole (CTZ) co-administration (15 mg kg-1 trimethoprim + 40 mg kg-1 sulphamethoxazole) on plasma concentration and various pharmacokinetic parameters of rifampicin (RIF, 24 mg kg-1) and isoniazid (INH, 14 mg kg-1) were studied. 2 In the test group (n = 6), CTZ was administered on the 24th day of antitubercular treatment (ATT) and given for 7 d. 3 At the end of concurrent treatment with CTZ, RIF half-life (t1/2) and plasma concentration were both increased. However, there was no effect on INH half-life and plasma concentration.

Animals↗

PubMed1992

A preliminary study on the interaction between ethanol and propranolol in normal human subjects.

Ethanol significantly increased the steady-state peak concentration of propranolol while propranolol significantly reduced the total body clearance of ethanol in healthy human volunteers. Ethanol per se caused tachycardia and rise in systolic blood pressure while propranolol administration resulted in bradycardia. In combinations, ethanol and propranolol caused significant fall in diastolic blood pressure without any significant changes in the heart rate and systolic blood pressure compared to the control readings of four healthy male volunteers. The kinetic and haemodynamic interactions observed between ethanol and propranolol in the preliminary study are of clinical relevance and need further exploration.

Adult↗

PubMed1991

Memory enhancing effects of granisetron (BRL 43694) in a passive avoidance task.

Recent evidence suggests that serotonin plays an important role in learning and memory processes in animals. The present study examined the effect of the 5-HT3 receptor antagonist, granisetron (BRL 43694), on acquisition, retention and retrieval of a passive avoidance response in mice. Granisetron (1 and 10 micrograms/kg) administered 30 min before presentation of footshock increased the step-down latency when tested 24 h after footshock. The acquisition process was not affected by a dose of 100 micrograms/kg. Granisetron (10 and 100 micrograms/kg) produced a significant increase in latency to step out of the safety zone, when administered immediately after or 23.5 h after footshock. However, at 1 microgram/kg, granisetron had no effect. These results confirm the important role played by 5-HT in the process of learning and memory, and also suggest that memory enhancement may be possible with non-cholinergic treatments.

Animals↗

PubMed1991

Diazepam-atenolol combination antagonizes aminophylline-induced convulsions and lethality in mice.

The present study was undertaken to identify protective drugs against aminophylline (240 mg/kg i.p.)-induced convulsions and lethality in mice. Diazepam (10 mg/kg) and valproic acid significantly prevented the convulsions, but were not effective in preventing mortality. Phenytoin, atropine, carbamazepine and atenolol were ineffective in protecting against convulsions and death. Ketamine gave partial protection against convulsions, but was not effective in preventing mortality. Diazepam (10 mg/kg) and atenolol (5 mg/kg) administered together gave total protection against convulsions and death. These results show that aminophylline-induced convulsions are relatively resistant to antiepileptic drugs, and that a combination of diazepam and a beta-blocker (atenolol) has potential as an anti-aminophylline agent.

Aminophylline↗

PubMed1991

Post-coital antifertility action of Ruta graveolens in female rats and hamsters.

Different preparations of Ruta graveolens were administered orally to female rats (Days 1-10 post coition) and female hamsters (Days 1-6 post coition). The powdered root (CDR), aerial parts (CDA) and the aerial parts aqueous extract (AEA) all showed potential anticonceptive activity in rats. Limited administration on selected days of CDA showed uniformly lesser activity than with 10-day treatment. Sequentially prepared petroleum ether and methanol extracts of CDA were as active as CDA itself. The benzene and chloroform extracts were toxic and inactive. Rutin, a known chemical constituent of the plant, was found to be inactive. None of the above preparations showed activity in hamsters.

Animals↗

PubMed1991

Effects of morphine on memory: interactions with naloxone, propranolol and haloperidol.

The effects of morphine on memory have been shown to be dependent on the strain of animal used and on the experimental parameters. Memory was assessed in a passive avoidance task using Swiss albino (ICRC) mice. Morphine at doses of 1, 3 and 10 mg kg-1 was administered immediately after foot shock (memory retention) or 23.5 h after foot shock (memory retrieval). Retest step-down latencies measured 24 h later showed that morphine did not affect memory retention but dose-dependently impaired retrieval of memory. Administration of naloxone 0.1 mg kg-1 antagonised the effects of morphine and impaired memory retention. Propranolol 0.3 mg kg-1 along with morphine 3 mg kg-1 impaired memory retention only while haloperidol 0.1 mg kg-1 improved the impairment of memory retrieval caused by morphine 3 mg kg-1. Glucose did not alter the effects of morphine on memory. There was no per se effect of morphine, naloxone, propranolol, glucose and haloperidol on memory at the doses used. The effect of morphine on memory retention is mediated by opioid mechanisms; however, adrenergic and dopaminergic mechanisms possibly modulate retention and retrieval of memory, respectively.

Animals↗

PubMed1991

Controlled clinical trial of nifedipine alone and in combination with dilazep in patients with angina pectoris.

The present study was performed to see if the combined treatment with nifedipine and dilazep offers any advantage over monotherapy with nifedipine alone in angina of effort. Thirty-three patients out of 40 with classical stable angina of effort completed this double-blind, randomized, parallel design comparative clinical trial. Both nifedipine alone (15-60 mg) and in combination with dilazep (50 mg) three times a day produced a significant reduction in angina attacks, consumption of nitroglycerin tablets and increased exercise tolerance. There was, however, no difference in the reduction in these parameters between the two groups. There was no significant reduction in blood pressure both systolic as well as diastolic and rate pressure product both when nifedipine was given alone and when it was given in combination with dilazep. Laboratory data did not reveal any dysfunction of liver, kidney and hemopoietic system. The results obtained show that there was no beneficial effect of adding dilazep to nifedipine therapy in the treatment of angina pectoris.

Angina Pectoris↗

PubMed1991

Effect of fatty diet on pharmacokinetics and pharmacodynamics of a liquid theophylline preparation in volunteers.

The effect of a standard breakfast and a fatty breakfast on the pharmacokinetics and pharmacodynamics of a theophylline liquid preparation (160 mg-single dose) was examined in 6 healthy, non-smoking male volunteers. The plasma theophylline concentrations after both standard and fatty diet were found to be comparable at each point of time and pharmacokinetic parameters like Cmax, Tmax, T1/2a, T1/2 beta and AUC0-alpha, were also comparable. However, the time taken to attain the therapeutic plasma concentration was earlier and sustained along with the standard breakfast in comparison to that with fatty breakfast. Peak change in PEFR and pulse rate was also observed earlier with the standard diet than with fatty diet. The plasma theophylline concentrations produced after both diets were insufficient to produce any detectable change in subjective symptoms like tremor palpitation, heart burn, nausea, restlessness and tenseness. However, theophylline after fatty breakfast was better tolerated than that after a standard breakfast.

Adult↗

PubMed1991

Patients' attitude towards health care at a teaching hospital in India.

Using a questionnaire, 362 patients attending the outpatients services of Internal Medicine of Nehru Hospital attached to our institution were randomly interviewed. Seventy per cent of the patients were in the 21-50 years age range; 50% came from rural and 50% from urban areas. Forty per cent travelled more than 30 Km; 72% used a public transport to reach hospital. Most patients had an income less than Rs. 1000/-. Ninety per cent had already consulted another medical practitioner earlier. The largest number of complaints related to the gastrointestinal, cardiovascular and respiratory systems. On an average 1-2 drugs were prescribed per patient; only 13% of these were available at the hospital dispensary. Most patients were willing to purchase the prescribed drugs from the market.

Adult↗

PubMed1991

Antimicrobial drug use in urology.

Antimicrobial drug utilization patterns were studied on patients in the Urology Ward of Nehru Hospital attached to the Postgraduate Institute of Medical Education and Research, Chandigarh. The study was done over a six-month period in which antimicrobial prescription for all patients admitted under urology services were monitored and followed. There were 57 cases of benign hypertrophy of the prostate, 40 of urinary calculi and 20 each of congenital malformation, malignancies, strictures and other conditions. Gentamycin and cotrimoxazole were the most frequently used antimicrobials, as calculated by the DDD/100 bed days.

Adult↗

PubMed1991

Determination of the optimal analgesia-potentiating dose of caffeine and a study of its effect on the pharmacokinetics of aspirin in mice.

The addition of caffeine 10 mg/kg to analgin, paracetamol and aspirin increased the potency of the combination compared to that of the analgesic used alone, giving a potency ratio of 1.58, 2.5 and 3.23, respectively as assayed by the writhing method in mice. Increasing the dose of caffeine further reduced the potency of the combination so that with 100 mg/kg caffeine the potency ratio for the combination against the analgesic alone was analgin 1.25, paracetamol 0.94 and aspirin 0.88. The Cmax, Tmax, t1/2 and AUC of plasma salicylate was not significantly different when aspirin 65 mg/kg was given alone or in combination with caffeine 10 mg/kg p.o. in mice. Therefore, caffeine is maximally effective in potentiating the effect of analgesics at a dose of 10 mg/kg and this potentiation is not due to a pharmacokinetic interaction with the analgesic, and also not due to phosphodiesterase (PDE) inhibition.

Acetaminophen↗

PubMed1991

Topical corticosteroids usage in dermatology.

Prescribing of topical corticosteroids was studied in 200 patients attending the dermatology outpatients, randomly auditing the written prescriptions. Data with regard to potency, quantity, frequency, duration and site of application was collected and analyzed. Potent topical steroids were commonly used in 86 (43%) patients. The quantity of topical steroid was mentioned in only 4% patients whereas the frequency was specified in 77%, the site in 69% and the duration in 55% patients, respectively. The importance of these parameters is discussed, guidelines regarding use of topical steroids suggested.

Administration, Topical↗