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Biomedical subjects

K Das

Publications and source records attributed to K Das.

At least 199 records · Page 11Linked to original sources
PubMed1979

Effect of short-term cold stress on the respiratory metabolism of brain tissue homogenates of male garden lizards of two different age-groups.

The endogenous oxygen uptake and the uptake with added substrate of whole-brain and mid-brain homogenates were significantly lower in older lizards as compared to younger. Both whole brain and mid-brain showed responses to cold stress for different lengths of time but the decline in oxygen uptake was more pronounced in the younger age-group. Respiratory rate and response to cold stress were more marked in the mid-brain than in the whole brain. Basing on earlier reports on mammals and on the present findings, it is suggested that the decline in physiological adaptation in older animals may be a general feature in vertebrates.

Adaptation, Physiological↗
PubMed1975

Affinity chromatography of enzyme cofactors: the separation of NAD on immobilised dehydrogenase colums.

1. Alcohol dehydrogenase (EC 1.1.1.1.) has been immobilised to aminoethyl-cellulose by glutaraldehyde, to DEAE-cellulose by an s-triazine derivative and to agarose using CNBr. Lactate dehydrogenase has been immobilised to the latter two supports. 2. Their use for affinity chromatography of NAD was compared and alcohol dehydrogenase immobilised to CNBr-activated agarose chosen for detailed study due to the efficient coupling of applied enzyme and the specific nature of binding. 3. The efficiency of coupling of alcohol dehydrogenase dropped from 94.5 to 72.2% when the applied load was increased from 18 to 54 mg/g activated agarose. Activity relative to free enzyme fell from 21 to 11%. The binding of NAD was maximal between pH 5.5 and 6. With the lowest loading of enzyme, NAD binding fell from 450 to 320 mug/g support when the linear flow rate was increased from 0.84 to 3.95 cm/min. 4. NAD was completely separated from a mixture with ATP, ADP and AMP. Separation from NMN and hydrolysed RNA and DNA was evidently possible. Immobilised alcohol dehydrogenase used for 34 binding experiments over a period of weeks maintained 60% of its original enzyme activity. 5. The method was applied to yeast NAD following mechanical disruption of yeast, clarification and either ultrafiltration or hollow-fibre dialysis to permit separate purification of macromolecules and nucleotides.

Alcohol Oxidoreductases↗
PubMedDate not supplied

Genetic variation at three VNTR loci in three tribal populations of Orissa, India.

BACKGROUND: The variable number of tandem repeats (VNTR) loci are robust, simple and rapid tools for genetic characterization of both individuals and populations. This paper presents data on the distribution of three VNTRs (APOB, YNZ22 and D1S80) in three tribal populations (Gadaba, Kuvi-Khond and Paroja) of the Koraput district of Orissa, India with a view to enlarge our understanding of molecular genetic diversity among these tribes and the usage of these VNTRs in anthropogenetic studies. SUBJECTS AND METHODS: Three tribal populations were genotyped for APOB, YNZ22 and D1S80 loci using the polymerase chain reaction (PCR) technique. Gadaba are an Austro-Asiatic tribe while Kuvi-Khond and Paroja are Dravidian tribes. All samples were collected, with consent, from unrelated individuals. RESULTS: The observed allelic variation in these tribes is comparable with many Indian populations, but they showed significant overall and inter-population variability within the region. Allele *24 was the most common allele at the D1S80 locus in all populations, with Gadabas having the highest frequency (50%) followed by Paroja (32%) and Kuvi-Khond (23%). Gadabas also showed a higher frequency of allele *19 (13%) and *31 (9%) compared to other Indian and European populations. In the Apo B system, allele *37 was the most common in all three populations, with Gadabas having the highest frequency (39%) followed by Paroja (24%) and Kuvi-Khond (21%). This allele is present in high frequencies in other Indian (except Gonds) and European populations. Alleles *33 (17%), *35 (20%) and *45 (12%) were also common in the Gadabas, but Kuvi-Khond showed higher frequencies of *31(10%), *35(13%) and the larger allele *49(16%). Paroja, on the other hand, had higher frequencies of *31 (14%), *33 (17%) and *45 (13%). Allele *49 was also present in Paroja (10%) but was absent in the Gadaba. For the YNZ22 system, allele *4 was the most common in Kuvi-Khond (25%) and Paroja (21.4%), and allele *2 was the predominant allele in the Gadaba (33%). However allele *4 still occurs at relatively high frequency in Gadaba (27%). Allele *2 also occurs at relatively high frequency in Kuvi-Khond (20%) and intermediate frequency in Paroja (11%). Average heterozygosity was relatively low for Gadaba (0.7597 +/- 0.0191) and high for Kuvi-Khond (0.8618 +/- 0.0149) and Paroja (0.8512 +/- 0.0190), perhaps a reflection of effective population size and limitations to mating. The level of gene differentiation is, however, low (3-4%) for the three systems studied in these tribal populations and in data compiled from previous studies from the region. CONCLUSIONS: The VNTRs are polymorphic in the tribal populations studied and there is extensive allelic variation. Gadabas are isolated but Kuvi-Khond and Paroja show clear affinities with the Gonds, a major tribal group of Central India. Overall, allele frequency distribution, heterozygosity and genetic diversity analysis show that genetic diversity observed is socially, linguistically and geographically structured in this region.

Alleles↗
PubMedDate not supplied

Assessment of nonallelic genetic heterogeneity of chronic (type II and III) spinal muscular atrophy.

We have previously reported the mapping of the chronic (type II/intermediate and type III/mild/Kugelberg-Welander) form of the childhood-onset spinal muscular atrophies (SMA) to chromosome 5q11.2-13.3, with evidence for nonallelic genetic heterogeneity within a small sample of seven families [Brzustowicz et al., Nature 1990;344:540-541]. We now report the results of linkage analysis and heterogeneity testing on a set of 38 families with chronic SMA. Significant evidence for nonallelic heterogeneity was detected among these families, with the predominant locus for chronic SMA mapping to a 0.51-cM region on 5q, between the loci D5S6 and MAP1B. The estimated proportion of linked families, alpha, was 0.91, with a 2.3-unit support interval of 0.75 to 0.98. The indication that some families diagnosed with chronic SMA are not linked to chromosome 5q must be considered in strategies to map the SMA locus. The relevance of these findings to acute SMA (SMA type I, severe, Werdnig-Hoffmann disease) is still unknown.

Adolescent↗
PubMedDate not supplied

Immunogenicity and reactogenicity of an inactivated hepatitis A vaccine in Indian adults.

BACKGROUND: In India, a possible decrease in the prevalence of anti-HAV (hepatitis A virus) antibodies in adults has increased their susceptibility to HAV infection. We evaluated the immunogenicity and reactogenicity of an inactivated hepatitis A vaccine administered in a 3-injection protocol. METHODS: Thirty-five healthy adult volunteers, seronegative for anti-HAV IgG, were administered 720 ELISA units/ml of the inactivated hepatitis A vaccine intramuscularly at days 0, 30 and 180. Anti-HAV IgG was determined at days 30, 60, 90 and 180 to assess the efficacy of the vaccine and adverse reactions were noted to evaluate its reactogenicity. RESULTS: The mean (SD) age of the volunteers was 33.1 (12.3) years and the man:woman ratio was 19:16. An overall seroprotection of 37.2% (13/35) was obtained at day 30, 57.1% (20/35) at day 60 and 85.7% (30/35) at day 90. By day 180, all the vaccinees (35/35; 100%) achieved protective seroconversion. The vaccine in general was well tolerated and no serious side-effects were observed. Only 8.6% (3/35) of subjects developed minor self-resolving adverse reactions such as local pain, erythema and/or low-grade fever. CONCLUSIONS: The inactivated hepatitis A vaccine in a three-injection protocol (0, 30 and 120 days) is safe, well tolerated and highly immunogenic in adult Indian subjects.

Adolescent↗
PubMedDate not supplied

Management of hydrocephalus.

The present study is an analysis of 747 patients with hydrocephalus, treated and followed up in the Hydrocephalus Clinic run by the department of Paediatric Surgery at the All India Institute of Medical Sciences, New Delhi. The distribution of patients was: congenital-46%, post-meningomyelocoele excision-28%, post-meningitic-21% and others-5% (including post haemorrhagic and post encephalocoele excision hydrocephalus. The average age was 7 months in the shunted group and 10 months in the medical group with overall male to female ratio of 2.3:1. The data were analysed to study the effect of treatment on ventriculomegaly and mental development with special reference to the type of treatment (shunt versus medical) and age at starting treatment. The probability of shunt failure was also studied. A comparison of ventricular size in US/CAT scans between the time of starting treatment and last follow-up revealed improvement in ventriculomegaly in 60% of the shunted patients but only 30% of the medically treated patients. A significant difference was particularly noted in patients with severe hydrocephalus, 72% and 22%, respectively. Comparison of the mean Mental Performance Quotient (MPQ) scores in the shunted & medically treated patients also revealed significantly better MPQ scores in the shunted group (p = < 0.001). Probability of shunt survival, as depicted by the Kaplan-Meier survival curve, revealed that there is a high rate of shunt failure in the first 12 months, followed by a dramatic slowing down. Our observations support the contention that CSF shunt surgery offers better outcome than medical management even when ventriculomegaly is severe at the time of presentation.

Cerebral Ventricles↗
PubMedDate not supplied

Non specific jejunoileitis--a report of 8 cases.

Nonspecific jejuno-ileitis is a nonocclusive, necrotizing inflammation of the small intestine. We treated 8 patients of jejuno-ileitis in a short span of 8 months. Their mean age was 8.6 years. All had acute pain in abdomen and most had hematochezia. Radiology was helpful only in diagnosis of complications of the disease. Four patients responded to conservative management; the other 4 required surgery--laparotomy and lavage in 2, and multiple laparotomies with resections in 2. One patient died due to chronic malnutrition and metabolic complications. Bowel histology was suggestive of resolving vasculitis in one patient and chronic inflammation in another patient.

Adolescent↗