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Biomedical subjects

S K Bansal

Publications and source records attributed to S K Bansal.

At least 19 recordsLinked to original sources
PubMed2005

Bioanalytical method development and validation for a large peptide HIV fusion inhibitor (Enfuvirtide, T-20) and its metabolite in human plasma using LC-MS/MS.

A method for measuring a human immunodeficiency virus (HIV) cell membrane fusion inhibitor (T-20/Ro 29-9800) and its metabolite (M-20/Ro 50-6343) in human plasma by liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed. The relatively large peptide analytes and their corresponding deuterated (d(10)) peptides used as internal standard were isolated from plasma by protein precipitation with two volumes of acetonitrile to plasma. A large pore size reversed-phase C(18) column was employed to elute the peptides. A triple quadrupole mass spectrometer with electrospray interface operating in positive ion and multiple reaction monitoring modes with transitions m/z 1124-->1343 for both T-20 and M-20 was utilized for peak detection. The advantages of the method were a simple sample preparation, specific and sensitive MS/MS detection, and a wide dynamic range of 10-2000 ng/ml for T-20. The method was validated and used for analyzing samples from clinical studies to provide pharmacokinetic profiles of the HIV fusion inhibitor peptide drug and its metabolite.

Adsorption↗
PubMed2005

Selective beta(1)-adrenoreceptor blocking activity of newly synthesized acyl amino-substituted aryloxypropanolamine derivatives, DPJ 955 and DPJ 890, in rats.

The in-vivo beta-adrenoreceptor antagonistic activity of test compounds DPJ 955 and DPJ 890 was assessed against beta-adrenoreceptor agonist (isoprenaline) induced tachycardia in anaesthetized rats. The selectivity to block isoprenaline responses on different &beta-adrenoreceptor subtypes (beta(1), beta(2) and beta(3)) of the test compounds was carried out on isolated rat right atria, isolated rat uterus and isolated rat colon preparations, respectively. Intravenous injection of isoprenaline alone in anaesthetized rats caused hypotension and tachycardia. DPJ 955 or DPJ 890 alone produced a fall in mean arterial pressure and bradycardia in a dose-dependent manner. Administration of isoprenaline to anaesthetized rats pre-treated with test compounds significantly blocked both the tachycardial and hypotensive responses induced by isoprenaline. The test compounds shifted the concentration response curves of isoprenaline towards the right for isolated rat right atrial preparations, rat uterus and rat colon, indicating beta(1), beta(2) and beta(3) adrenoreceptor blockade, respectively. The selectivity ratio for beta(1)/beta-adrenoreceptors to DPJ 955 and DPJ 890 was 64.6 and 83.2, respectively. DPJ 890 was more potent in blocking beta(1)-adrenoreceptors and was more selective towards beta(1) receptors than to other beta-adrenoreceptor subtypes. In conclusion, DPJ 955 and DPJ890 have beta-adrenoreceptor blocking activity with high selectivity for the beta(1)-adrenoreceptor subtype.

Acetamides↗
PubMed2004

Study of beta-adrenoreceptor antagonistic activity of DPJ 904 in rats.

beta-Adrenoreceptor antagonistic activity of a newly synthesized compound was evaluated in vivo by measuring the mean arterial blood pressure and heart rate of urethane-anesthetized rats treated with isoprenaline. In vitro beta(1)-, beta(2)- and beta(3)-antagonism was studied using isolated rat right atria, isolated rat uterus and isolated rat colon preparations, respectively, in comparison to isoprenaline response. DPJ 904 (1, 3 and 10 mg/kg, i.v.) produced dose-dependent hypotensive and bradycardia response in anesthetized rat. DPJ 904 (1, 3 and 10 mg/kg, i.v.) significantly inhibited both the tachycardial effects and hypotensive response induced by isoprenaline. DPJ 904-antagonized isoprenaline induced positive chronotropic effects of isolated rat right atria and a uterine relaxant effect indicating beta(1)- and beta(2)-blockade. The parallel shift to the right of the concentration-response curve of isoprenaline in the presence of DPJ 904 in KCl (30 mmol/l) induced contraction of the rat colon suggesting that DPJ 904 also possessed beta(3)-adrenoreceptor antagonistic activity. The selectivity to beta(1)-adrenoreceptor was nearly 20.5 times greater than to beta(2)-adrenoreceptor. The present study indicates that DPJ 904 possesses beta-adrenoreceptor antagonistic activity with slightly more affinity to the beta(1)-adrenoreceptor subtype.

Adrenergic beta-Agonists↗
PubMed2004

Efficacy of different organophosphate and synthetic pyrethroid insecticides to the larvae of malaria vector Anopheles stephensi, Liston.

Evaluation of the potency of four organophosphate (OP) (Malathion, Fenthion, Fenitrothion and Temephos) and two synthetic pyrethroid (SP) compounds (cypermethrin and deltamethrin) was carried out against larvae of Anopheles stephensi, the major malaria vector in district Bikaner (Rajasthan). Different concentrations supplied by WHO were used for determining the percent mortalities. LC50 values as calculated by probit analysis were 1.2740, 0.0600, 0.0405, 0.0046, 0.0019 and 0.0016 mg/l respectively for the above six insecticides. Both SP compounds were found more toxic followed by temephos among the OP compounds. Malathion was found the least toxic while fenthion and fenitrothion were in between these two extremes.

Animals↗
PubMed2003

Insecticide susceptibility status of Aedes aegypti to DDT and dieldrin in desert and non-desert parts of Rajasthan.

Seasonal prevalence and insecticide susceptibility tests were carried out on the adults of Aedes aegypti, the vector of dengue and dengue hemorrhagic fever(DF/DHF), in three desert (Bikaner, Jaisalmer and Jodhpur) and three non-desert (Alwar, Ajmer and Jaipur) districts of Rajasthan. Among the three species viz. Ae. aegypti, Ae. vittatus and Ae. w-albus encountered during the survey the former was the most prevalent species. Studies were carried out both in rural and urban areas against different concentrations of two organochlorines (DDT and Dieldrin). In rural areas resistance has been observed with DDT and dieldrin both in desert and non-desert parts while an intermediate resistance has been observed in the urban areas with both the insecticides which required further verification. Resistance was more pronounced in rural areas as compared to urban areas. LC50 along with regression equation and Chi-square values have been determined for both the insecticides.

Adaptation, Physiological↗
PubMed2001

Multiple isoforms of protein kinase C in lymphocytes and airway smooth muscle of guinea pig.

The isoenzyme pattern of protein kinase C (PKC) in lymphocytes and airway smooth muscles (ASM) was examined by Western blot using commercially available monoclonal antibodies. The results showed the presence of PKC alpha, beta, gamma, epsilon, eta, mu and zeta in lymphocytes and PKC alpha, gamma, epsilon, eta and zeta in ASM. The unexpected feature was the presence of PKCgamma in both lymphocytes and ASM of guinea pigs. Expression of this PKC isoform is usually restricted to tissues in the central nervous system or spinal cord. Expression of PKC delta, theta, lambda and tau was not detected in either lymphocytes or ASM.

Animals↗
PubMed2000

Effect of feeding protein deficient diet on phospholipid turnover and protein kinase C mediated protein phosphorylation in rat brain.

Feeding of protein deficient diet is known to alter the transmembrane signalling in brain of rat by reducing total protein kinase C (PKC) activity. Phospholipid metabolism regulates the activation of PKC through generation of second messengers and the extent of PKC activation accordingly influences the magnitude of phosphorylation of its endogenous substrate proteins. Thus it was speculated that ingestion of protein deficient diet may modify the turnover rate of membrane phospholipids and magnitude of phosphorylation of endogenous substrate proteins of PKC. The experiments were conducted on rats fed on three different types of laboratory prepared diets viz. casein (20% casein), deficient (4% protein, rice flour as source of protein) and supplemented (deficient diet supplemented with L-lysine and DL-threonine) for 28 days. The metabolism of phosphoinositides (PIs) and phosphatidyl choline (PC) was studied by equilibrium labeling with [3H] myo inositol and [14C methyl] choline chloride respectively. The phosphorylation of endogenous substrate proteins of PKC was studied by using 32P-gamma-ATP followed by SDS-PAGE and autoradiography. The results suggest that in deficient group, there is an increased incorporation of [3H] myo inositol in PIs and inositol phosphate pool in comparison to the casein group. The phosphatidyl inositol (PI) turnover reduced, although there was a marginal increase in the phosphatidyl inositol monophosphate (PIP) and phosphatidyl inositol bis phosphate (PIP2). Supplementation of diet showed a reversal of the pattern towards control to a considerable extent. In the deficient group, PC metabolism showed an increased incorporation of [14C methyl] choline in choline phospholipids but decreased incorporation in phosphoryl choline in comparison with the casein group. The increase in total PC contents was significant but marginal in residue contents. The turnover rate of PC increased only marginally and that of residue declined. Supplementation of diet reduced the total contents of PC and residue, but the turnover rate of PC and residue remained still higher. Phosphorylation of endogenous proteins showed four different proteins of 78, 46, 33 and 16 kDa to be the substrates of PKC in casein group. In deficient group, phosphorylation of these proteins increased markedly while supplementation of diet had a reversing effect rendering the values to be intermediate between casein and the supplemented group. The changes in phospholipid metabolism and in phosphorylation of endogenous substrate proteins of PKC suggest that dietary protein deficiency causes alterations in transmembrane signalling mechanism in rat brain. These effects are partially reversed by improving the quality of proteins in the diet.

Animals↗
PubMed1999

Predictors of asthma severity in the elderly: results of a community survey in Northeast England.

A number of risk factors for the development and severity of asthma in childhood are known. Particularly, there is information on allergens, excessive use of beta2- agonists, and indoor environmental pollutants. Similar information on elderly patients is lacking. We examined the risk factors for current asthma and for the severity of asthma in 95 elderly subjects (>65 years old) compared to 274 elderly subjects with obstructive spirometry who did not have asthma as defined by the following criteria: symptoms of episodic wheeze, cough, or chest tightness and forced expiratory volume in 1 sec/vital capacity (FEV1/VC) <70% with >15% or 200 mL reversibility in FEV1 to 200 microg salbutamol given from a metered-dose inhaler. The severity of airflow limitation was graded on the basis of the FEV1/VC ratio as mild (60%-70%), moderate (40%-60%), and severe (<40%). Asthma history was collected using the Medical Research Council respiratory questionnaire and a follow-up postal questionnaire. Data were analyzed using multiple logistic regression and the overall goodness-of-fit of the model was checked using the Hosmer-Lemeshow (HL) statistic. History of allergy (to one or more of the following allergens: cat, house dust, or grass or tree pollen) (odds ratio [OR] 25; 95% confidence interval [CI] 13-51; p = 0.0001) and history of childhood wheeze (OR 8; 95% CI 4-9; p = 0.004) were strong predictors of current asthma. Duration of wheezing, smoking history, indoor heating, history of working in coal mines, and sex were not predictors (HL 6.75, degrees of freedom [df] = 8, p = 0.56). Use of >4 puffs of salbutamol/ day (OR 5.3; 95% CI 2-14; p = 0.005), more than 10 years of asthma symptoms (OR 4.2; 95% CI 4.1-36.2; p = 0.0001), and >500 mL reversibility in FEV1 (OR 4.2; 95% CI 1.2-14.3; p = 0.05) were independent predictors of moderate to severe asthma. History of atopy was the strongest predictor of asthma in the elderly population studied. Indoor heating, presence of pets at home, sex, smoking history, and history of working in coal mines were not predictors of asthma. The severity of asthma as assessed by measurement of airflow limitation was related to the frequency of use of beta2-agonists, duration of symptoms of asthma, and increased reversibility of FEV1 to beta2-agonist.

Aged↗
PubMed1999

Effect of fiberoptic bronchoscopy on arterial blood gases and cardiac rhythm at a moderate altitude of 2250 meters.

OBJECTIVES: To study the effects of fiberoptic bronchoscopy (FOB) at an altitude of 2250 m on arterial blood gases (ABG) and cardiac rhythm abnormality. METHODS: Fifty consecutive patients undergoing fiberoptic bronchoscopy were evaluated for the arterial blood gases and cardiac rhythm changes at Shimla (a moderate altitude of 2250 m), where there is a state of ambient hypoxia. RESULTS: The changes were noted in five stages ranging from the levels before the procedure till 15 minutes after the completion of the procedure. The mean fall in PaO2 levels in this study was 8 +/- 2.45 mm Hg and the fall was maximum at the end of procedure. Both smokers and nonsmokers showed a significant fall but the fall was more severe in smokers. The mean fall in SaO2 in this study was 3%. The increase in heart rate and blood pressure during FOB was significant as compared to baseline levels. There was no significant change in PH, PaCO2, HCO3. The commonest rhythm abnormality noted was sinus tachycardia which was well tolerated. No major cardiac arrhythmia was noted. It was further seen that the duration of the procedure and type of special procedure undertaken did not effect the levels significantly. Cyanosis was the commonest complication encountered (36%) and was seen more frequently in smokers and those with age more than 40 years. It was observed during the induction of bronchoscope and also during the further negotiation of the bronchoscope into the smaller branches of bronchial tree. CONCLUSION: The changes in ABG and cardiac rhythm are comparable to the studies at sea level except the increased incidence of cyanosis.

Adolescent↗
PubMed1998

Asthma in the elderly: underperceived, underdiagnosed and undertreated; a community survey.

Bronchial asthma is now increasingly recognized in the elderly and is associated with significant morbidity and mortality. The aims of this study were two-fold: first, to assess the prevalence and, second, to evaluate diagnostic awareness, therapeutic management and patient perception of bronchial asthma among elderly patients in the community. From the age-sex register of an urban general practice in NE England, 2004 patients aged > 65 years were eligible for inclusion. Response to an initial screening questionnaire on respiratory symptomatology was 68% (n = 1362). Of these, 869 patients had respiratory symptoms: 390 voluntarily agreed to be evaluated further including assessment of airway physiology. In this group 369/390 had obstructive spirometry and, of these, 95 patients fulfilled clinical and physiological criteria of bronchial asthma. Prevalence of asthma within this age cohort was minimally and rather crudely assigned at 4.5% (95/2004). Among the 95 patients so-defined patients with asthma [age 70 +/- 8 years (mean +/- SD), FEV1 = 0.96 +/- 0.41, 33 male, 75 life-long non-smokers], subjective awareness, perception and attribution of pulmonary symptoms were poor. Further, despite tangible evidence of reversible and significant airflow limitation, only 21 were receiving inhaled glucocorticoid therapy (median daily dose 400 micrograms). Asthma in the elderly remains poorly perceived, poorly recognized and suboptimally treated. These findings are particularly apposite in the light of current epidemiological trends in asthma mortality and morbidity in elderly age cohorts.

Aged↗
PubMed1997

Increased levels of protein kinase C in lymphocytes in asthma: possible mechanism of regulation.

Asthma is an inflammatory disease of the airways. Activation of lymphocytes leads to elaboration of inflammatory mediators which are likely to initiate and perpetuate the asthmatic response. During activation of lymphocytes, the role of protein kinase C (PKC) has been emphasized. Therefore, changes in PKC activity in peripheral blood lymphocytes in bronchial asthma can be expected, which may be due to alterations in the regulatory mechanisms of the enzyme molecule. To understand the mechanism of regulation of PKC activity the effects of drugs, such as carbachol, histamine, sphingosine and disodium cromoglycate (DSCG), on the lymphocytes of healthy subjects were studied. The study included 27 asthmatic patients and 14 healthy volunteers. Disease was classified as mild, moderate-to-severe, and cases in remission. PKC activity was determined in peripheral blood lymphocytes by [3H] phorbol 12,13-dibutyrate ([3H]PDBu)-binding assay. A highly significant (p < 0.001) increase was observed in total, cytosolic and membrane PKC activity in all of the asthmatic patients as compared to the healthy group. There was an increased translocation of PKC from cytosol to membrane in all of the groups, and the extent of translocation of the enzyme indicates physiological activation of the cells. A highly significant (p < 0.001) reciprocal relationship (r = -0.47) existed between forced expiratory volume in one second (FEV1) as percentage predicted and total PKC activity in bronchial asthma. Carbachol and histamine significantly (p < 0.001) increased PKC activity in lymphocytes, the increase being dose-dependent for histamine. Sphingosine or disodium cromoglycate (DSCG) brought about complete inhibition of PKC activity at 100 nM. We conclude that protein kinase C activity is increased in lymphocytes in bronchial asthma. Our findings suggest that the mediators (carbachol and histamine), and drugs (sphingosine and disodium cromoglycate) possibly exert their action on protein kinase C by influencing the regulatory domain of the enzyme.

Adolescent↗
PubMed1997

Dietary protein deficiency induced changes in protein kinase C activity and phospholipid metabolism in rat hepatocytes.

Dietary protein deficiency is known to alter the protein kinase C activity in various tissues of rats. Protein kinase C activity is influenced by the metabolism of membrane phosphoinositides and phosphatidyl choline (PC). For metabolic studies, hepatocytes have been the cells of choice of various workers. Therefore, studies on protein kinase C and these phospholipids were conducted in hepatocytes of rats maintained on three different diets viz. casein (20% protein) deficient (4% protein, rice flour as source of protein) and supplemented (deficient diet supplemented with L-lysine and DL-threonine) diet for 28 days. The protein deficiency in diet led to a decline in protein kinase C activity (P < 0.01) without effecting its translocation, an increase in phosphatidyl inositol 4,5-bisphosphate (P < 0.001) and a decrease in phosphatidyl inositol 4-monophosphate and phosphatidyl inositol (P < 0.01) but did not alter the PC contents, as compared to the casein group. Supplementation of deficient diet with L-lysine and DL-threonine could considerably reverse the effect of deficiency of protein in diet. The results suggest that quality of dietary protein is mainly relevant for maintaining phospholipid metabolism and physiology of hepatocytes and thus the signalling mechanism in these cells.

Animals↗
PubMed1996

Insecticide susceptibility status of some anophelines in district Bikaner, Rajasthan.

Insecticide susceptibility tests were conducted on the adults of four anopheline species namely. Anopheles annularis, An. culicifacies, An. stephensi and An. subpictus against the diagnostic doses of six insecticides, viz. DDT (4.0%), dieldrin (0.4%), malathion (5.0%). fenitrothion (1.0%), propoxur (0.1%) and permethrin (0.25%) in District Bikaner (Rajasthan). A time dependent effect has been observed with each insecticide. All the four species were found resistant to DDT and dieldrin and susceptible to fenitrothion and permethrin. An culicifacies and An. subpictus showed susceptibility to malathion, while further verification for the other two species was required. However, with propoxur An. annularis showed resistance, whereas for other three species further studies are required. DDT and dieldrin, the two organochlorines, were found least effective as compared to organophosphates and carbamates.

Animals↗
PubMed1996

Current status of Anopheles stephensi response to various insecticides in some areas of the Thar desert.

Investigations on the current response of A. stephensi. to six insecticides viz. DDT, dieldrin, malathion, fenitrothion, propoxur and permethrin, were carried out in 3 districts i.e. Barmer, Jodhpur and Pali, of the Thar desert. The species was found resistant to DDT and dieldrin, partially resistant to malathion and susceptible to fenitrothion, propoxur and permethrin. Dieldrin and malathion resistance has been detected for the first time in the Thar desert. Lethal concentrations (LC50 & LC95) of DDT and dieldrin and lethal exposure times (LT50 & LT95) of malathion, fenitrothion, propoxur and permethrin have been determined. In some areas, the differences in LC50 and LT50 values of tested insecticides, except fenitrothion, were found statistically significant. Chi-square and regression tests have revealed the homogeniety and linear trend respectively in the response of A. stephensi to insecticides. The findings of the study indicate that organochlorine compounds can be used alternately in the spray operations.

Animals↗
PubMed1996

Insecticide susceptibility of Phlebotomus papatasi to organochlorine, organophosphate & carbamate compounds in some arid areas of western Rajasthan.

Insecticide susceptibility status of P. papatasi to organochlorine, organophosphate and carbamate compounds has been estimated in Pali and Barmer districts of Rajasthan. Tests revealed that this species was resistant to DDT but susceptible to dieldrin, malathion, fenitrothion and propoxur. Efficacies to these compounds at 50 and 95 per cent levels have been estimated by probit-analysis. The LC50 values for both DDT and dieldrin, were found much lower than those reported from other parts of the country. Heterogeneity of the response was found highly significant [X2 = 43.8(3)] in case of propoxur only.

Animals↗
PubMed1996

Differential activity of protein kinase C in alveolar and peritoneal macrophages.

The characteristics of protein kinase C activity present in guinea pig alveolar and peritoneal macrophages have been compared and examined. The activity is predominantly cytosolic with preference for phosphatidyl serine as cofactor over other phospholipids. K(m) of protein kinase C for ATP is 30.30 and 54.05 microM in alveolar and peritoneal macrophages respectively. Scatchard plot analysis shows heterogenous binding sites for [3H]PDBu in alveolar macrophages in contrast to peritoneal macrophages showing homogeneous type of binding sites. PMA activates protein kinase C in a dose-dependent manner and shows downregulation at higher concentration in both alveolar and peritoneal macrophages. Endogenous proteins of molecular masses 77, 47, 37 and 16.5 kDa in alveolar macrophages and 77, 47, 38 and 15.5 kDa in pertioneal macrophages are phosphorylated by PKC. These findings suggest that alveolar and peritoneal macrophages possess two different types of protein kinase C activities but phosphorylate similar proteins and exhibit functional similarities in these cells.

Animals↗
PubMed1996

Susceptibility status of Phlebotomus papatasi and Sergentomyia punjabaensis (Diptera:Psychodidae) to some insecticides in district Bikaner (Rajasthan).

Susceptibility tests were carried out on the females of two species of sandflies viz. Phlebotomus papatasi and Sergentomyia punjabaensis against six insecticides viz. DDT, dieldrin (organochlorines); malathion, fenitrothion (organophosphates); propoxur (carbamate) and permethrin (synthetic pyrethroid) in district Bikaner, Rajasthan. A concentration and time dependent effect was observed with insecticides for both the species. P. papatasi was found resistant to DDT, dieldrin and propoxur while susceptible to malathion, fenitrothion and permethrin. However, S. punjabensis was found susceptible to all the insecticides tested. LC50 and LT50 value estimated for DDT and dieldrin for P. papatasi and S. punjabaensis were found to be 2.2 and 0.3% x 1 hr and 1.45 and 0.032% x 15 min. respectively.

Animals↗