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Biomedical subjects

M K Das

Publications and source records attributed to M K Das.

At least 37 records · Page 2Linked to original sources
PubMed2002

Paediatric immunisation: special emphasis on measles and MMR vaccinations.

The dictum, 'prevention is better than cure', is applicable to all ailments but it can be most easily followed for infectious diseases, increasing numbers of which are being contained by specific vaccinations since the first discovery of smallpox vaccine by Edward Jenner in 1796. Advances in immunology and laboratory techniques including cell culture, genetic engineering and animal experiments have contributed significantly to the production of more and more vaccines, used successfully in preventive programmes. Infectious diseases are widely prevalent in the developing countries. The child population is specially vulnerable to many of them. These infections contribute to high morbidity and mortality and immunisation programmes have been undertaken as preventive measures against them at the national level. Paediatricians and experts are actively engaged in formulating and improving these programmes as problems are faced in their implementation. Much new information is continuously being available in the literature, mostly in specialised journals. The general practitioners, particularly those serving in the remote and vast rural areas, are not likely to have access to these recent developments which they need for self-motivation in initiating the parents with confident advice to have their children properly immunised and also for tackling effectively any problem arising out of immunisation. This paper attempts to discuss the subject of paediatric immunisation with special emphasis being laid on measles and MMR vaccinations.

Adolescent↗
PubMed2001

Prognostic value of exercise echocardiography in 2,632 patients > or = 65 years of age.

OBJECTIVES: We sought to determine the prognostic value of exercise echocardiography in the elderly. BACKGROUND: Limited data exist regarding the prognostic value of exercise testing in the elderly, a population which may be less able to exercise and is at increased risk of cardiac death. METHODS: Follow-up (2.9 +/- 1.7 years) was obtained in 2,632 patients > or = 65 years who underwent exercise echocardiography. RESULTS: There were 1,488 (56%) men and 1,144 (44%) women (age 72 +/- 5 years). The rest ejection fraction was 56 +/- 9%. Rest wall motion abnormalities were present in 935 patients (36%). The mean work load was 7.7 +/- 2.3 metabolic equivalents (METs) for men and 6.5 +/- 1.9 METs for women. New or worsening wall motion abnormalities developed with stress in 1,082 patients (41%). Cardiac events included cardiac death in 68 patients and nonfatal myocardial infarction in 80 patients. The addition of the exercise electrocardiogram to the clinical and rest echocardiographic model provided incremental information in predicting both cardiac events (chi-square = 77 to chi-square = 86, p = 0.003) and cardiac death (chi-square = 71 to chi-square = 86, p < 0.0001). The addition of exercise echocardiographic variables, especially the change in left ventricular end-systolic volume with exercise and the exercise ejection fraction, further improved the model in terms of predicting cardiac events (chi-square = 86 to chi-square = 108, p < 0.0001) and cardiac death (chi-square = 86 to chi-square = 99, p = 0.004). CONCLUSIONS: Exercise echocardiography provides incremental prognostic information in patients > or = 65 years of age. The best model included clinical, exercise testing and exercise echocardiographic variables.

Age Factors↗
PubMed2001

Stabilisation of [131I]meta-iodobenzylguanidine at room temperature as organic extract in ethyl acetate/chloroform.

A method of purification of [131I]mIBG (diagnostic dose) by solvent extraction and possibility of its stabilisation by storage in ethyl acetate and chloroform at up to 40 degrees C for not less than 14 days is described. In order to further enhance the utility of this finding, the organic extract was dispensed into vials and dried. Vials containing such dried residue of [131I]mIBG stored at up to 40 degrees C was also found to be stable for at least 10 days. The final product reconstituted as aqueous solution resulted in 90% recovery with 99% radiochemical purity as assessed by previously reported methods, as well as a relatively more rapid paper chromatography method standardised by us. These interesting findings promise simpler and economic packaging besides transport of diagnostic doses of [131I]mIBG.

3-Iodobenzylguanidine↗
PubMed2001

Purification and stabilization of 99mTc-d,l-HMPAO: role of organic extractants.

99mTc-d,l-HMPAO, an important SPECT agent for imaging cerebral perfusion, suffers from the disadvantage of an inherent instability and its shelf life has been reported to be 30 min. The latter is a harsh constraint and not compatible with Centralized Radiopharmacy procedures. During the attempts to improve upon the stability of 99mTc-d,l-HMPAO, preservation of product as an organic extract into suitable solvents like diethylether, ethylacetate, methylethylketone, chloroform was tried out. Chloroform extraction (yield: >90%) resulted in a product having stability not less than 5 hours. Gentle drying of the chloroform extract and reconstitution in normal saline resulted in quantitative recovery of 99mTc-d,l-HMPAO with acceptable radiochemical purity (>90%). This finding is thus of much significance, especially in the context of centralized large hospital radiopharmacy setting, by rendering convenience and flexibility in scheduling patients.

Drug Stability↗
PubMed2001

Prolonged QRS duration (QRS >/=170 ms) and left axis deviation in the presence of left bundle branch block: A marker of poor left ventricular systolic function?

BACKGROUND: Left bundle branch block (LBBB) is commonly associated with structural heart disease and left ventricular dysfunction. We propose that the QRS duration and degree of left-axis deviation (LAD) identify significant left ventricular systolic dysfunction in patients with LBBB. METHODS: In this prospective study the ejection fraction (EF) of 300 consecutive patients with LBBB was evaluated by echocardiography. The relationship between QRS duration and LAD (axis between -30 degrees and -90 degrees ) and EF were derived. RESULTS: There was no significant difference in age, sex, presence of ischemic or nonischemic cardiomyopathy and valvular heart disease, and EF among the patients with or without LAD. The EF of patients with QRS >/=170 milliseconds with LAD (n = 20) and without LAD (n = 18) was 25% +/- 16% and 23% +/- 13%, respectively (P =.71). The mean EF (24% +/- 10%) of the patients with a QRS duration of >/=170 milliseconds (n = 38) was significantly lower than the mean EF (36% +/- 16%) of the patients with a QRS duration of <170 milliseconds (n = 262, P <.015). The QRS duration also had a significant (P <.001) inverse correlation with EF (R = 0.37, adjusted R (2) = 0.13, SE of estimate = 16.21). However, the QRS axis was not significantly correlated with EF and did not have added predictive value. CONCLUSIONS: The QRS duration has a significant inverse relationship with EF and prolongation of QRS duration (>/=170 milliseconds) in the presence of LBBB is a marker of significant left ventricular systolic dysfunction. The presence of LAD in LBBB does not signify a further decrease in EF.

Bundle-Branch Block↗
PubMed2000

Assessment of cardiac risk before nonvascular surgery: dobutamine stress echocardiography in 530 patients.

OBJECTIVE: This study evaluated the incremental value of dobutamine stress echocardiography (DSE) for assessment of cardiac risk before nonvascular surgery. BACKGROUND: Limited information exists regarding the preoperative assessment of cardiac risk in patients with known or suspected coronary artery disease who are to undergo nonvascular surgery. METHODS: All patients (303 men, 227 women) who underwent DSE before nonvascular surgery and did not sustain an intervening event (coronary revascularization or cardiac event) were studied. Clinical, electrocardiographic and rest and stress echocardiographic variables were evaluated to identify predictors of postoperative cardiac events. RESULTS: Events occurred in 6% of patients: 1 cardiac death and 31 nonfatal myocardial infarctions. All of these patients had inducible ischemia on DSE (sensitivity 100%, specificity 63%). Multivariate predictors of postoperative events in patients with ischemia were history of congestive heart failure (p = 0.006; odds ratio = 4.66; confidence interval 1.55 to 14.02) and ischemic threshold less than 60% of age-predicted maximal heart rate (p = 0.0001; odds ratio 7.002; confidence interval 2.79 to 17.61). Clinical variables of Eagle's index identified 21% of patients as low, 68% as intermediate and 11% as high risk preoperatively; the postoperative event rates were 3%, 6%, and 14%, respectively. Dobutamine stress echocardiography identified 60% of patients as low (no ischemia), 32% as intermediate (ischemic threshold 60% or more) and 8% as high risk (ischemic threshold < 60%); postoperative event rates were 0%, 9% and 43%, respectively. CONCLUSIONS: In this population of patients with known or suspected coronary artery disease evaluated before nonvascular surgery, DSE had incremental value over clinical, electrocardiographic and rest echocardiographic variables for identifying patients at low, intermediate and high risk for postoperative cardiac events. Ischemia occurring at less than 60% of age-predicted maximal heart rate identified patients at highest risk.

Adult↗
PubMed2000

Molecular genetic diversity in 5 populations of Madhya Pradesh, India.

This paper presents data on the distribution of 3 amplified fragment length polymorphisms (D1S80, APOB, and YNZ22) in 5 populations of Central India. Using the polymerase chain reaction technique, 3 caste (Brahmin, Khatri, and Dhimer) and 2 tribal (Gond and Baiga) populations were studied for the 3 loci. The allelic variations observed in the caste populations are compatible with those of many Caucasian populations, but the caste populations showed significant overall and interpopulation variability within the region. D1S80 allele *24 varied from 32% (Dhimers) to 42% (Brahmins). Allele *18 was not observed in Baiga tribal populations, but in caste populations it varied from 11% (Dhimers) to 24% (Brahmins). Both tribal populations showed higher frequencies of allele *31 (17%-18%). For APOB, caste populations again showed bimodal distribution of alleles *35 and *37, but in tribal populations higher allele numbers (*47, *49) were also frequent. For YNZ22, extensive variation was observed for all populations studied. Allele *4 was the most common in caste populations, while alleles *2, *7, and *10 were prominent in tribal populations. The level of gene differentiation is not very high for the 3 systems studied in the 5 populations. Overall, allele frequency distribution, heterozygosity, and genetic diversity analysis show that the genetic diversity observed is socially and geographically structured.

Alleles↗
PubMed2000

A four year follow up study of filaria specific IgE response in individuals with hydrocele.

BACKGROUND & OBJECTIVES: Hydrocele is the most common clinical manifestation in males infected with Wuchereria bancrofti. IgE response to a filarial allergen Sd30 was evaluated in hydrocele patients living in a W. bancrofti endemic region of Orissa, India. METHODS: IgE levels to Sd30, an antigenic fraction isolated from Setaria digitata, were determined by ELISA in sera from patients of filariasis (n = 93). IgG and IgM levels were also determined. RESULTS: It was observed that microfilaraemic patients with hydrocele (n = 16) exhibited considerably reduced (P < 0.01) IgE levels in comparison to hydrocele patients without microfilariae (n = 27) and to other filarial groups (elephantiasis, asymptomatic microfilaraemics). The reduced IgE response in microfilariae positive patients with hydrocele persisted even after a gap of four years in the majority of patients. INTERPRETATION & CONCLUSIONS: The results show low IgE levels in microfilaraemic patients with hydrocele in comparison to other groups in filaria endemic regions. The exact mechanism of this reduction in IgE is not known but these patients make a distinct group in filaria endemic regions and should be considered separately for immunological evaluation.

Adult↗
PubMed1999

Antibody response to a filarial antigen fraction in individuals exposed to Wuchereria bancrofti infection in India.

An antigen fraction (DssdI) was isolated from the aqueous-insoluble components of adult Setaria digitata. Rabbit antiserum to DssdI labeled the sheaths of Wuchereria and Setaria microfilariae suggesting DssdI to be surface associated. Antibody responses to DssdI were determined in Wuchereria bancrofti exposed individuals. IgM titre was highest in endemic normals (EN; asymptomatic amicrofilaraemic) followed by chronic filarial patients (CP) and asymptomatic microfilaraemics (AS). IgG titer was high in both chronic filariasis and endemic normals. The microfilaraemic group had the lowest titer. The seropositivity rate in AS was 28% for IgG and 10% for IgM, in CP 100% for IgG and 33% for IgM, and in EN 86% for both antibodies. An age-dependency of IgM but not of IgG antibodies was observed in endemic normals, with IgM prevalence reaching a plateau by 12 years of age. The subclass composition of the antibody response to DssdI appeared to be primarily IgG3 in endemic normals, IgG1 in chronic filariasis and IgG4 in asymptomatic microfilaraemics. Diethylcarbamazine (DEC) treatment led to a significant increase in IgG and IgM levels in microfilaraemic individuals. Of interest, the expression of IgG subclasses altered. There was an increased IgG3 and IgG1 response associated with a reciprocal decrease in IgG4 following DEC therapy.

Adolescent↗
PubMed1999

A paper chromatographic technique for quantitative evaluation of hydrolysed and ionic components in 201Tl radiopharmaceuticals.

A reported paper chromatographic technique has been extended to delineate the hydrolysed components in 201Tl radiopharmaceuticals for the determination of radiochemical purity. Detailed radiochemical purity analysis of 201TlCl has been demonstrated using mini paper chromatographic systems. The technique is also useful in evaluation of the radiochemical purity of 67Ga and 111In radiopharmaceuticals.

Chromatography, Paper↗
PubMed1999

Antigenicity of a filarial protease from Setaria digitata in Wuchereria bancrofti infection.

A protease isolated from adult Setaria digitata revealed a single, 110-kDa band in a gelatin-impregnated, substrate gel. Analysis with specific inhibitors indicated it to be a metallo-protease. IgG from chronic filarial patients living in an area of Orissa, India, endemic for Wuchereria bancrofti was able to neutralize the proteolytic activity of this enzyme completely. IgG from asymptomatic microfilaraemics and endemic normals (asymptomatic amicrofilaraemics) only caused partial inhibition and IgG from non-endemic normals was ineffective. The generation of inhibitory antibodies appears to depend on the severity of filariasis. Evaluation of IgG-subclass response to the protease indicated the dominance of IgG4 antibodies in asymptomatic carriers and of IgG1 in those with chronic filariasis. The IgG3 response was minimal and the IgG2 responses were similar for each of the filarial groups. When IgG4-subclass serology using the protease antigen was assessed, 47 of 50 microfilaraemics, 20 of 50 endemic normals and 23 of 50 chronic patients but none of 20 non-endemic normals were found seropositive. Appreciable levels of specific IgE, which correlated with those of IgG4, were detected in all filarial groups. IgG4 was detected in 35 out of 70 children (aged < 12 years) who appeared amicrofilariaemic and 38 of 40 microfilaraemic children.

Animals↗
PubMed1999

Acute nonspecific carditis in adolescents presenting with Stokes-Adams attacks.

Three patients, aged between 12 and 17 years presented with Stokes-Adams attacks as a result of atrioventricular block, atrioventricular silence and ventricular arrhythmias, complicating acute myocarditis. All the patients required temporary pacing for a few days. One patient required hemodialysis for anuria. All the patients made complete recovery.

Adams-Stokes Syndrome↗
PubMed1998

Evaluation of the binding of the radiolabeled antidepressant drug, 18F-fluoxetine in the rodent brain: an in vitro and in vivo study.

We have developed 18F-fluoxetine as a radiotracer analog of the antidepressant drug fluoxetine (Prozac). In vitro saturation experiments of 18F-fluoxetine were carried out on rat midbrain tissue and citalopram was used for measuring nonspecific binding. A saturation curve for the binding of 18F-fluoxetine was not obtained. Even when fluoxetine (10 microM) was used for measurements of nonspecific binding, a saturation curve was difficult to obtain. Other compounds, such as deprenyl, clorgyline, amphetamine, and reserpine were also not able to reduce the binding of 18F-fluoxetine. Ex vivo autoradiographic experiments with 18F-fluoxetine did not reveal any specific uptake in various brain regions. In vivo administration of 18F-fluoxetine in rats showed similar uptake in all the brain regions with little regional selectivity. A subcellular analysis of rat brain tissue after intravenous (IV) administration of 18F-fluoxetine indicated significant amounts of binding in mitochondria and synaptosomes. In summary, in vitro experiments with 18F-fluoxetine indicate little specific binding. Binding to the serotonin transporter was not identifiable. High nonspecific binding of the tracer resulting from its subcellular nature in the brain masks the ability to detect binding to the serotonin uptake sites in vivo. These findings indicate that a large portion of the binding of 18F-fluoxetine in rat brains is subcellular and clears slowly out of the cells. Other sites, such as monoamine oxidase, may also play a significant role in the action of fluoxetine.

Animals↗
PubMed1998

Mosquito fauna and breeding habitats of anophelines in Car Nicobar Island, India.

A total of 31 species of mosquitoes belonging to 10 genera, i.e. Anopheles, Aedes, Armigeres, Culex, Harpagomyia, Hodgesia, Mansonia, Orthopodomyia, Toxorhynchites and Uranotaenia were collected from Car Nicobar Island. Four Anopheles species, An. barbumbrosus, An. insulaeflorum, An. kochi and An. roperi were recorded for the first time from this Island. An. sundaicus was the most predominant species encountered. The results of the study on anophelines with emphasis on species-specific breeding preference in various aquatic habitats have been recorded.

Animals↗