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Biomedical subjects

J B Patel

Publications and source records attributed to J B Patel.

34 records · Page 2Linked to original sources
PubMed1984

Neurochemical characteristics of rats distinguished as benzodiazepine responders and non-responders in a new conflict test.

Using a new rat conflict test it was found that 30% of the subjects failed to respond to benzodiazepines and other anxiolytic agents. This value is similar to that reported using more classical procedures such as the Geller-Seifter and Vogel conflict tests. Biochemical analysis of various brain regions from responder (R) and non-responder (NR) subjects revealed no significant differences in 5-HT1, 5-HT2, GABA receptor binding or GABA-activated benzodiazepine binding. However, a small, but significant, increase in basal benzodiazepine binding was noted in the hippocampus of NR rats. These findings suggest that the insensitivity of these animals to anxiolytics is probably unrelated to an alteration in serotonin, GABA or benzodiazepine binding sites in brain.

Animals↗
PubMed1983

Novel non-benzodiazepine anxiolytics.

Several new non-benzodiazepine anxiolytics are reported. These include tracazolate, zopiclone, CL218,872, CGS9896, buspirone, MK-801 and fenobam. A comparison of anticonflict effects and propensity to cause sedation and potentiate the actions of ethanol is given as well as their effects upon the binding of [3H]flunitrazepam in vitro. Their anxiolytic properties after treatment with the benzodiazepine antagonist, RO15-1788, are reported also. Tracazolate shows a wide separation between anxiolytic activity and ability to cause sedation and to potentiate alcohol. It enhanced binding of [3H]-flunitrazepam in contrast to benzodiazepines which displace it. Buspirone was without anticonflict activity and had no effect on benzodiazepine binding while fenobam and MK-801, also without effect on binding, showed large and small differences on causing sedation and potentiating alcohol respectively. Among the displacers of [3H]flunitrazepam zopiclone showed diminished sedation liability, compared to diazepam, as did CL218,872 and CGS9896. Zopiclone caused potentiation of ethanol however, at doses close to anxiolytic doses, while CL218,872 and CGS9896 showed a wider safety margin for potentiation of ethanol compared to anxiolytic doses. The drug RO15-1788 antagonised the anticonflict effects of benzodiazepine displacers and had no effects upon the other agents studied.

Animals↗
PubMed1982

Differential antagonism of the anticonflict effects of typical and atypical anxiolytics.

Selected benzodiazepine and non-benzodiazepine agents were studied alone or in the presence of benzodiazepine antagonists in the shock-induced suppression of drinking (SSD) procedure in rats. The disinhibitory activity of chlordiazepoxide, CL218,872, zopiclone and CGS 9896 was antagonized by two benzodiazepine antagonists, RO-15-1788 and CGS 8216. In contrast, the disinhibitory activity of fenobam, meprobamate, phenobarbital and tracazolate was not antagonized by either RO 15-1788 and CGS 8216. From these data it is apparent that the anticonflict activity of agents that bind to benzodiazepine receptors is blocked by benzodiazepine antagonists. In contrast, the activity of anxiolytics that are not displacers are unaffected even at higher doses.

Animals↗
PubMed1982

Pharmacological properties of tracazolate: a new non-benzodiazepine anxiolytic agent.

Tracazolate (ICI 136,753, 4-butylamino-1-ethyl-6-methyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylic acid ethyl ester) demonstrated dose-related anticonflict activity in rats and mice. The potency of tracazolate appears to be one-quarter to one-half that of chlordiazepoxide. No tolerance to the anticonflict activity of either tracazolate or chlordiazepoxide was evident following 12 consecutive days of treatment. Tracazolate exhibits a much greater separation between sedative and therapeutic doses than does chlordiazepoxide. Furthermore, based on rodent studies, tracazolate should be much less likely than the benzodiazepines to potentiate the actions of barbiturates and ethanol in man. Tracazolate potentiated both the anticonvulsant and anxiolytic effects of chlordiazepoxide in rodents. Unlike benzodiazepines, tracazolate enhances the binding of benzodiazepines to its receptor site. These results suggest that tracazolate is a novel agent with potential clinical utility as an anxiolytic drug.

Animals↗
PubMed1982

A sensitive and selective monkey conflict test.

A conflict model is described in which clinically effective antianxiety agents exhibit pronounced anticonflict activity. Male squirrel monkeys were trained to depress a bar for 5 sec to obtain food reinforcement. The 6 hr test session was comprised of an initial 3 hr period in which each 5 sec response was punished and then a 3 hr unpunished period. Trained monkeys would rarely be shocked and would make most of their responses during the non-punished period. Both benzodiazepine (chlordiazepoxide and diazepam) and non-benzodiazepine (meprobamate and phenobarbital) anxiolytics produced pronounced and unequivocal increases in punished responding. Other psychoactive agents (damphetamine, chlorpromazine, ethanol, morphine, amitriptyline and imipramine) did not produce an increase in punished responding. Sensitivity (i.e., large magnitude effects), selectivity, stable baseline performance and fully automated features make this test useful in identifying potential anxiolytic agents in primates.

Animals↗
PubMed1980

Effects of isoproterenol and chlordiazepoxide on drinking and conflict behaviors in rats.

Isoproterenol, a beta-adrenergic agents, induced drinking in water-satiated rats. Isopropeternol exhibited significant anti-conflict activity on water-deprived rats in the Shock-induced Suppression of Drinking (SSD) procedure. Chlordiazepoxide (CDP), at the highest dose tested, also increased drinking in non-deprived naive rats. As expected, CDP demonstrated highly significant anti-conflict activity in thirsty rats (SSD test). These results suggest that in conflict procedures, where food or water is used as a reward, agents that affect the consumatory drive mechanisms could show up as "false positives." Moreover, agents that affect primary drives (e.g., CDP), in addition to their anti-anxiety activity, could show additive activity in such conflict procedures.

Animals↗
PubMed1979

Benzodiazepine blockade of passive-avoidance task in mice: a state-dependent phenomenon.

Four benzodiazepines (diazepam, chlordiazepoxide, halazepam, lorazepam) were tested for their effects on the acquisition of a passive-avoidance task in mice. This was done to determine whether amnesic effects, as reported in humans after diazepam and lorazepam, could be demonstrated by blockade of passive-avoidance responding in mice and, if so, to investigate the possible causes of the blockade by studying the relationships between the blockade and times of drug administration. Each of these benzodiazepines, at doses that did not alter overt behavior, blocked acquisition of the passive-avoidance response when they were administered to mice prior to the training session, but not when they were administered after the training session or prior to testing 24 h later. The block of avoidance responding was reversed, however, when the drugs were administered prior to both training and test sessions. These results suggest that state-dependent learning occurred; i.e., apparent amnesia occurred in the test session with untreated mice that had undergone passive-avoidance learning 24 h earlier under the influence of drug.

Animals↗
PubMed1977

Flunixin meglumine: a non-narcotic analgesic.

The N-methyl-d-glucamine salt of flunixin (flunixin meglumine) is a potent non-narcotic analgesic agent after parenteral administration in mice, rats and monkeys. It is significantly more potent than pentazocine, meperidine and codeine in the rat yeast paw test after subcutaneous administration in saline. Activity on intramuscular administration is comparable to that after subcutaneous administration and is enhanced when dissolved in buffered saline as compared to nonbuffered saline. In addition, flunixin meglumine also had oral activity and differs from indomethacin in having more analgesic activity per unit of anti-inflammatory activity. In mice, flunixin meglumine is equipotent to pentazocine and more potent than meperidine and codeine in the abdominal constriction test. In primates, flunixin meglumine at 10 mg/kg i.m., produced a degree of analgesic efficacy comparable to that of a clinically effective dose of morphine (0.3 mg/kg). In contrast to codeine, tolerance to the analgesic action of flunixin meglumine was not observed. Furthermore, flunixin meglumine retained its activity in rats made tolerant to codeine. Unlike narcotics, the analgesic effect of flunixin meglumine is not antagonized by naloxone after acute administration in rats. These results indicate that flunixin meglumine is a parenterally and orally effective analgesic in animals and is unlikely to have narcotic or drug dependence liability.

Analgesics↗
PubMedDate not supplied

Early congenital syphilis: clinico-radiologic features in 202 patients.

Venereal syphilis is highly prevalent among women of child-bearing age in Zambia. It is estimated to contribute 25-30% of the perinatal mortality rate of 50 per 1,000 births at the University Teaching Hospital in Lusaka. Because of multisystem involvement, early congenital syphilis, the offshoot of maternal syphilis, has varied criteria for its diagnosis. Therefore, in an attempt to draw guidelines for an easier and more reliable diagnosis, the authors analyzed the clinico-radiologic features of congenital syphilis in 202 patients. Although all infants were under the age of six months, there were several significant differences in the manifestations of the disease among neonates and the postneonates. The younger infants had a higher incidence of jaundice and mortality, whereas joint swellings, skin rash, snuffles, anemia, and periosteal reaction visible in x-rays of long bones were typical findings among the older group. The radiologic changes were seen in greater than 95% of patients in both groups. About 84% of mothers had attended prenatal clinics, but less than 20% of the women had been tested for syphilis. Since early congenital syphilis is common in many parts of the world and since all serologic tests have limitations, awareness of appropriate diagnostic criteria is recommended for all medical personnel.

Age Factors↗
PubMedDate not supplied

Evaluation of serum alkaline DNase activity in treatment monitoring of head and neck cancer patients.

Our previously published data on breast cancer suggest that serum alkaline DNase, a known circulating tumour marker, can be used for treatment monitoring of cancer patients. Serum alkaline DNase activities were analyzed in 215 untreated head and neck cancer patients. The enzyme activity ranged from 0.17 to 97.97 IKU/l in untreated cancer patients. Responders (n = 314) showed significantly elevated activity of alkaline DNase as compared to untreated cancer patients (p < 0.001). While non-responders (n = 168) showed comparable activity with untreated cancer patients. Serum alkaline DNase activities were significantly elevated in responders as compared to non-responders (p < 0.001). Our clinical studies during follow-up of patients indicated that the variations in serum alkaline DNase activities in individual patients correlate closely with response to therapy. Serum alkaline DNase also appeared to be useful in predicting treatment response in the long-term follow-up of patients. Serum alkaline DNase was systematically examined as a possible indicator for recurrence in patients under complete remission. In conclusion, serum alkaline DNase may be useful as a treatment monitoring in patients with head and neck malignancies.

Adolescent↗
PubMedDate not supplied

Simultaneous determination of losartan and hydrochlorothiazide in combined dosage forms by first-derivative spectroscopy and high-performance thin-layer chromatography.

Losartan (LST) is the first orally active nonpeptide angiotensin-II receptor antagonist with an improved safety and tolerability profile. It is prescribed alone or in combination with hydrochlorothiazide (HCTZ) for the treatment of moderate-to-severe hypertension. This paper describes the development of 2 methods that use different techniques, first-derivative spectroscopy and high-performance thin-layer chromatography (HPTLC), to determine LST and HCTZ in the presence of each other. LST and HCTZ in combined preparations were quantitated by using the first-derivative responses at 271.6 nm for LST and 335.0 nm for HCTZ in spectra of their solutions in water. The linearity ranges are 30-70 microg/mL for LST and 7.5-17.5 microg/mL for HCTZ with correlation coefficients of 0.9998 and 0.9997, respectively. In the HPTLC method, a mobile phase of chloroform-methanol-acetone-formic acid (7.5 + 1.5 + 0.5 + 0.03, v/v) and a prewashed Silica Gel G60 F254 TLC plate as the stationary phase were used to resolve LST and HCTZ in a mixture. Two well-separated and sharp peaks for LST and HCTZ were obtained at Rf values of 0.61+/-0.02 and 0.41+/-0.02, respectively. LST and HCTZ were quantitated at 254.0 nm. The linearity ranges obtained for the HPTLC method are 400-1200 and 100-300 ng/spot with corresponding correlation coefficients of 0.9944 and 0.9979, for LST and HCTZ, respectively. Both methods were validated, and the results were compared statistically. They were found to be accurate, specific, and reproducible. The methods were successfully applied to the estimation of LST and HCTZ in combined tablet formulations.

Angiotensin Receptor Antagonists↗
PubMedDate not supplied

Alterations in plasma lipid profile patterns in head and neck cancer and oral precancerous conditions.

BACKGROUND: The changes in lipid profile have long been associated with cancer because lipids play a key role in maintenance of cell integrity. AIMS: The present study evaluated alterations in plasma lipid profile in untreated head and neck cancer patients as well as patients with oral precancerous conditions (OPC) and its association with habit of tobacco consumption. MATERIAL AND METHODS: This hospital-based case control study included 184 head and neck cancer patients, 153 patients with OPC and 52 controls. Plasma lipids including: (i) Total cholesterol, (ii) LDL cholesterol (LDLC), (iii) HDL cholesterol (HDLC) (iv) VLDL cholesterol (VLDLC) and (v) triglycerides were analysed by spectrophotometric kits. STATISTICAL ANALYSIS USED: Student's t-test was performed to compare mean values of the parameters. RESULTS: A significant decrease in plasma total cholesterol and HDLC was observed in cancer patients (P=0.008 and P=0.000 respectively) as well as in patients with OPC (P=0.014 and P=0.000, respectively) as compared to the controls. The plasma VLDL and triglycerides levels were significantly lower in cancer patients as compared to the patients with OPC (P=0.04) and controls (P=0.059). The tobacco habituates showed lower plasma lipid levels than the non-habituates. Our data strengthen the evidence of an inverse relationship between plasma lipid levels and head and neck malignancies as well as OPC. CONCLUSION: The lower levels of plasma cholesterol and other lipid constituents in patients might be due to their increased utilization by neoplastic cells for new membrane biogenesis. The findings strongly warrant an in-depth study of alterations in plasma lipid profile in head neck cancer patients.

Adult↗