Biomedical subjects
Publications and source records attributed to S Kumar.
A case of leiomyosarcoma of gallbladder, a rare tumor in hepatobiliary region, is reported. The present case differs from previously reported cases in its presentation with empyema of gallbladder and multiple intrahepatic cholangiolytic abscesses. Curative surgery could not be undertaken on account of poor condition of patient, and invasion of tumor into liver and adjacent organs.
Two protease populations have been identified in the somatic products of adult Necator americanus. One population (158, 138, 34 and 31 kDa) loses, whereas the other population (107, 74, 51 and 20 kDa) retains, its proteolytic activity after elution from substrate gels. The present study warns that hookworm proteases may oligomerise and/or lose their activity under the conditions necessary for their purification. We suggest that following assessment of protease activity on substrate gels, the protease of interest should be eluted from plain gels; their isolation from substrate gels may lead to a reduced or no yield.
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We have presented the case of a 34 year old male patient who was admitted with severe metabolic alkalosis (MA). Peak serum HCO3 was 96 mg/dl and compensatory PCO2 was 95 which, to our knowledge, has never been reported before in a patient with MA. MA was probably generated by consumption of high amount of NaHCO3 and renal impairment and maintained by impaired renal function due to volume depletion hypokalemia and hyochloremia. The patient was successfully treated with IV administration of saline and KCL.
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The v-Rel oncoprotein and its cellular homolog c-Rel belong to the Rel/kappa B family of transcription factors. Members of this family share extensive sequence similarity in their N-terminal halves, a region referred to as the Rel Homology Region (RHR), bind to NF-kappa B DNA motifs and form heterodimers with one another. Whereas c-Rel activates transcription of kappa B-linked genes, v-Rel behaves as a dominant-interfering mutant of c-Rel- and kappa B-mediated transcription activation. Here we describe two novel activities of the Rel oncoproteins. One induces kappa B-site dependent stimulation of polyomavirus (Py) DNA replication and maps to the N-terminus of the RHR, a region where no transcription activation function was detected. This activity is common to v-Rel, c-Rel, p52 (p49/lyt10), RelA (p65) and the p50 subunit of NF-kappa B. The second promotes transcriptional activation in undifferentiated F9 cells and maps 3' to the RHR, a region essential for the transforming activity of v-Rel.
Sterically stabilized neutral liposomes (multilamellar vesicles) were prepared by sonicating phosphatidylcholine and cholesterol (molar ratio 4:1) film in phosphate buffered saline (50 mM, pH 7.4) containing 4% Tween 20. Tc-99m-GHA was incorporated in these liposomes by treating 0.5 ml of the suspension with lyophilized GHA kit (5 mg GHA and 250 micrograms SnCl2 x 2 H2O) followed by addition of 1 ml 99mTcO4- (1-3 mCi). The labelling yield was 60-70%. Tween 20 has provided significant stability of the radiolabel as compared to that without its addition, when radiolabelled liposomes were incubated in serum up to 24 h. With respect to Tc-99m-GHA alone, radiolabelled liposomes exhibited 4- to 6-fold greater radioactivity in the blood of rabbits (15 min-24 h). Comparison of biodistribution data of radiolabelled liposomes and Tc-99m-GHA in mice demonstrated a 10- to 12-fold greater hepatic accumulation of radiolabelled liposomes with respect to that of Tc-99m-GHA throughout the period of study (15 min-24 h), though their concentration in the kidneys was comparable.
P3 component of event related cerebral evoked potentials has been applied as an index of information processing in a wide variety of normal and cognition impaired subjects. The present study was undertaken to examine possible changes in central nervous system processing and subjective appraisal, indexed by cerebral evoked potentials (N200 & P300), in 20 pain free controls and 20 subjects suffering from chronic pain (cervical spondylosis and low backache, sciatica). Standard auditory 'Odd ball' paradigm involving simple discrimination task of concentrating on infrequent (target) stimulus and ignoring the frequent stimulus (non-target) was employed. Evoked response trial of discriminating 32 target stimuli out of 160 total presented (20% target and 80% non target, randomly) were replicated and analysed by computer. There was significant increase in P3 latency in patients suffering from pain as compared to age and sex matched controls, suggesting change in cognitive functions.
Propranolol, a nonselective beta-adrenergic blocking agent, although prescribed frequently, has not been monitored for its adverse reactions in Indian population. A collaborative ADR monitoring study was planned in 2661 hypertensive patients. Exclusion criteria were associated circulatory insufficiency, heart block, left ventricular failure, diabetic mellitus and airway obstruction. The incidence of ADR was 2.1%, which is lower than reported incidence of 8.7 to 43.7 percent in other studies. This could be attributed to improper selection of patients, differences in methodology of monitoring, or to racial variation. In the present study ADR of fatigue (1.1%), dizziness (0.4%) and headache (0.2%) constituted the bulk. Additional reaction of pain in chest (0.2%), heart block (0.1%), hypoglycemia (0.1%), loss of libido (0.1%) and shock (0.03%), were also observed.
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The serum hyaluronan (HA) level of 238 women with breast cancer was measured by means of a specific radiometric assay. The results show no significant increase in serum HA when compared to levels in 120 control sera. A number of prognostic factors were evaluated including stage of disease, lymph-node involvement, tumour size, histology and presence of oestrogen and progesterone receptors in the tumour. No correlation was found with serum HA concentration and we conclude that serum HA level is of no prognostic significance in breast cancer.
Using a subtraction cloning approach we had previously isolated a series of murine cDNA clones representing the genes predominantly expressed in the embryonic brain and down-regulated during development. We now report that one of these cDNA clones encodes a novel type of GTP-binding protein. The predicted protein of 40.5 kD, named DRG, contains five structural motifs characteristic of the GTP-binding proteins. Consistently, bacterially expressed and cellular DRG proteins are capable of binding GTP in vitro. Sequences closely related to the DRG protein are found in other species including Drosophila and Halobacterium. Based on these observations, we propose that DRG represents an evolutionarily conserved novel class of GTP-binding protein which may play an important role in cell physiology.
We had previously characterised a cDNA which encodes a novel GTP-binding protein DRG. The expression of drg gene is down-regulated during the embryonic development of murine central nervous system. Further analysis of drg mRNA and protein in adult mouse tissues and various cell lines of different origins indicated that it is expressed widely, albeit at low and variable levels. In situ hybridisation analysis of mRNA expression in sections of mouse embryos indicated that drg is expressed strongly in various embryonic tissues. The expression of drg mRNA is greatly reduced in newborn animals. At cellular level, DRG protein can be detected in the cytoplasm. These observations suggest that DRG may play multiple roles in development and normal cell metabolism.
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A full length cDNA whose corresponding mRNA is down-regulated during the mouse embryonic brain development was isolated. The cDNA contains a single long open reading frame which could encode a protein with relative molecular mass of 41 kDa. The predicted gene product contains long stretches of prolines towards the NH2-terminus, followed by a leucine/proline rich region. The cDNA probe detected a number of mRNA species in Northern blot analysis. The reverse transcriptase-polymerase chain reaction analysis of mRNA from adult mouse tissues indicated that heart and testis expressed this gene (named NDPP-1) at relatively high levels, while lower levels of mRNA were detected in a number of other tissues. Expression of NDPP-1 was also detected in embryonic carcinoma and pheochromocytoma cell lines, but not in fibroblasts. The cDNA hybridized to genomic DNA from several vertebrates species in Southern blot analysis indicating interspecies conservation of this gene. The interesting pattern of expression of the NDPP-1 gene during mouse brain development and the structure of its putative protein product indicate that this gene may play an important biological role in the development of mouse central nervous system.
The type-II DNA-(cytosine-5)-methyltransferase M.HhaI was overexpressed in Escherichia coli and purified to apparent homogeneity. The purification scheme exploits a unique high salt back-extraction step to solubilize M.HhaI selectively, followed by FPLC chromatography. The yield of purified protein was 0.75-1.0 mg per gram of bacterial paste. M.HhaI could be isolated in two forms: bound with its cofactor S-adenosylmethionine (AdoMet) or devoid of the cofactor. The AdoMet-bound form was capable of methylating DNA in vitro in the absence of exogenous AdoMet. From kinetic studies of the purified enzyme, values for KmAdoMet (60 nM), KiAdoHye (0.4 nM), and Kcat (0.22 s-1) were determined. The purified enzyme bound with its cofactor was crystallized by the hanging drop vapor diffusion technique. Crystals were of monoclinic space group P2(1) and had unit-cell dimensions of a = 55.3 A, b = 72.7 A, c = 91.0 A, and beta = 102.5 degrees, with two molecules of M.HhaI in each of the two asymmetric units. The crystals diffract beyond 2.5 A and are suitable for structure determination.