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Biomedical subjects

S Kumar

Publications and source records attributed to S Kumar.

At least 73 records · Page 4Linked to original sources
PubMed1992

Rat brain creatine kinase messenger RNA levels are high in primary cultures of brain astrocytes and oligodendrocytes and low in neurons.

Rat brain creatine kinase (CKB) gene expression is highest in the brain but is also detectable at lower levels in some other tissues. In the brain, the CKB enzyme is thought to be involved in the regeneration of ATP necessary for transport of ions and neurotransmitters. To understand the molecular events that lead to high CKB expression in the brain, we have determined the steady-state levels of CKB mRNA in homogeneous cultures of primary rat brain astrocytes, oligodendrocytes, and neurons. Northern blot analysis showed that whereas the 1.4-kb CKB mRNA was detectable in neurons, the level was about 17-fold higher in oligodendrocytes and 15-fold higher in astrocytes. The blots were hybridized with a CKB-specific 32P-antisense RNA probe, complementary to the 3' untranslated sequence of CKB, which hybridizes to CKB mRNA but not CKM mRNA. Also, the 5' and 3' ends of CKB mRNA from the glial cells were mapped, using exon-specific antisense probes in the RNase-protection assay, and were found to be the same in astrocytes and oligodendrocytes. This indicated that (a) the site of in vivo transcription initiation in astrocytes and oligodendrocytes was directed exclusively by the downstream, nonconcensus TTAA sequence at -25 bp in the CKB promoter that is also utilized by all other cell types that express CKB and (b) the 3' end of mature CKB mRNA was the same in astrocytes and oligodendrocytes. In addition, there was no detectable alternate splicing in exon 1, 2, or 8 of CKB mRNA in rat astrocytes and oligodendrocytes.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

The RxxRxRxxC motif conserved in all Rel/kappa B proteins is essential for the DNA-binding activity and redox regulation of the v-Rel oncoprotein.

The v- and c-Rel oncoproteins bind to oligonucleotides containing kappa B motifs, form heterodimers with other members of the Rel family, and modulate expression of genes linked to kappa B motifs. Here, we report that the RxxRxRxxC motif conserved in all Rel/kappa B family proteins is absolutely required for v-Rel protein-DNA contact and its resulting transforming activity. We also demonstrate that serine substitution of the cysteine residue conserved within this motif enables v-Rel to escape redox control, thereby promoting overall DNA binding. These mutant proteins retained the ability to competitively inhibit kappa B-mediated transcriptional activation of the human immunodeficiency virus long terminal repeat but failed to efficiently transform chicken lymphoid cells both in vitro and in vivo. Our data indicate that reduction of the conserved cysteine residue in the RxxRxRxxC motif may be required for optimal DNA-protein interactions. These results provide direct biochemical evidence that the DNA-binding activity of v-Rel is subject to redox control and that the conserved cysteine residue in the RxxRxRxxC motif is critical for this regulation. These studies suggest that the DNA-binding, transcriptional, and biological activities of Rel family proteins may also be subject to redox control in vivo.

Base Sequence↗
PubMed1992

Immunohistochemical localisation of transforming growth factor-beta in first and third trimester human placenta.

Recently it has been demonstrated that human placental tissue is a source of transforming growth factor-beta (TGF-beta) and that it expresses high TGF-beta mRNA activity. For a better understanding of its in vivo function, it was necessary to determine the site of TGF-beta synthesis in placenta. We have demonstrated that TGF-beta immunoreactivity is present in the cytoplasm of syncytiotrophoblast cells in both early and term placenta. The most intense staining was, however, observed in the first trimester trophoblast syncytial sprouts known to be an early stage in the development of placental villi. These results suggest the involvement of TGF-beta in the paracrine regulation of trophoblast-endometrial interaction.

Chorionic Villi↗
PubMed1992

Management of malignant germ cell tumours of ovary.

Ten patients of the advanced malignant germ cell tumours of the ovary were treated by cisplatin based combination chemotherapy after initial conservation surgery. Eight patients completed course containing cisplatinum, vinblastine and bleomycin. Five patients (62.5%) achieved CR while 2 (25%) attained PR. One patient died due to tumour lysis and respiratory infection. Rest two patients did not turn up in follow up. Long term follow up indicates above regimen to be highly effective. However poor performance status, advanced stage of disease and post operative gross residual disease were poor prognostic factors in our patients.

Adolescent↗
PubMed1992

Acceptability trials with ready to eat foods in a rural area.

Acceptability trials with three types of recipes was carried out on 184 young preschoolers (6 months to 35 months) residing in four nearby villages around Hyderabad. Results of this study indicated that among the 3 types of supplementary foods (Sweet Ready Mix, Sweet Ready Mix with Amylase and Therapeutic food tested here, the Therapeutic food was more acceptable (taste, smell and bulk) to the children. The criteria for acceptability of the food was defined as the ability of 75% of the children to consume 75% or more of the food supplement at one sitting for 70% of the days of the trial. The Therapeutic food, a calorie dense supplement, met the above criteria. The acceptability was poor for the Sweet Ready Mix and Sweet Ready Mix with Amylase (< 4%) mainly due to quantity rather than taste and smell as revealed by the mothers. The mothers of the children also liked the taste and smell of the therapeutic food better. Consumption of the therapeutic food caused minimal side effects like diarrhea and vomiting when compared to side effects after eating Sweet Ready Mix and Sweet Ready Mix with Amylase in children.

Child, Preschool↗
PubMed1992

Quantitative estimation of urinary protein excretion by refractometry.

Quantitative estimation of proteinuria done by the refractometric method was compared with that done by the sulphosalycilic acid method and biuret method in 102 urine samples. The analysis of results by students' t test showed no statistically significant difference between the three methods. It is concluded that quantitative estimation of urinary protein excretion by refractometric method is a simple cheap and reliable method and can be performed easily in the outpatient clinic. The instrument is quite handy and can be carried in the pocket.

Benzenesulfonates↗
PubMed1992

Clinical and epidemiological features of acute gastroenteritis caused by human rotavirus subgroups.

Rotavirus was detected in 44 (15.28%) of 288 hospitalised children suffering from gastroenteritis in Delhi over a period of one year. Of these 44 children, subgroup I and II rotaviruses were detected in 13 (29.55%) and 25 (56.82%) children respectively. Samples from 5 (11.36%) children did not react with either subgroup I or II monoclonal antibodies, indicating the presence of a third subgroup. Both subgroups I and II were detected in one (2.27%) case. The median ages of the children infected by subgroup I and II rotavirus were 7 and 12 months respectively. Rotavirus was more prevalent in boys than in girls. The peak of rotavirus infection was seen in the early winter months. The difference of maximum and minimum monthly temperatures correlated significantly (p less than 0.05) with the incidence of rotavirus infection. Subgroup II was the predominant group throughout the period of study and caused a significantly higher incidence of severe diarrhoea than did subgroup I.

Acute Disease↗
PubMed1992

Incidence of mycoses in bronchopulmonary disorders.

A total of 274 samples were collected--180 sputum samples, 82 bronchial secretions and 12 pleural aspirates. Main fungus was Candida albicans from sputum (45.5 percent), from bronchial secretions (14.6 percent). Rest were Aspergillus, Alternaria and Helminthosporium. All the pleural aspirates were negative for fungus.

Adult↗
PubMed1992

Inhibition of cellular glutathione biosynthesis by rifampicin in Mycobacterium smegmatis.

This study was carried out to investigate the mechanism of Rifampicin (RIF) induced glutathione (GSH) depletion in M. smegmatis. RIF at various concentrations decreased the activities of gamma glutamyl cysteine synthetase (GGCS) and GSH synthetase. Maximum decrease in the activities of biosynthetic enzymes of GSH was observed when 15 micrograms RIF ml-1 medium was incorporated in the growth medium before performing inoculations. The activity of GGCS was also decreased when three day grown M. smegmatis was exposed to 60 micrograms RIF ml-1 medium for a period of 6 h and 9 h. RIF did not alter the activity of gamma glutamyl transferase. The results of the present study demonstrate that the depletion caused by RIF in cellular GSH is due to its decreased biosynthesis whereas its degradation is not affected in M. smegmatis.

Glutamate-Cysteine Ligase↗
PubMed1992

Secretion of metalloproteases by living infective larvae of Necator americanus.

Fresh living third-stage larvae of Necator americanus released a significant amount of label within 2 hr of their incubation on 125I-labeled gelatin-coated polystyrene plastic plates. This protease activity was primarily susceptible to o-phenanthroline, which identifies the activity as predominantly metalloprotease.

Animals↗