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Biomedical subjects

P Dasgupta

Publications and source records attributed to P Dasgupta.

At least 91 records · Page 5Linked to original sources
PubMed1989

Identification of alternatively spliced transcripts for human c-myb: molecular cloning and sequence analysis of human c-myb exon 9A sequences.

The murine c-myb gene has been recently shown to code for two protein products of 75kd and 89kd. The 89kd protein appears to be generated from an alternatively spliced mRNA which contains an additional stretch of 363 bases between exons 9 and 10. In this communication, we have examined whether similar alternatively spliced mRNAs of c-myb occur in human cells. Human c-myb exon 9A has been identified and sequenced in a cDNA clone (ML5) generated from the acute myeloid leukemic cell line ML-2. This alternatively spliced exon of c-myb has been found to contain the same number of nucleotides (363bp) as the corresponding mouse exon. Between murine and human exon 9A sequences, 81% sequence homology was found at the DNA level, while the homology at the predicted amino acid level was found to be 73%. A stretch of 14 amino acid residues at the junction of exons 9A and 10 have been found to be conserved between Drosophila and human sequences indicating that this region might perform an essential biological function which was deemed necessary through evolution.

Amino Acid Sequence↗
PubMed1988

Comparison of bevantolol and atenolol in chronic stable angina.

A randomized, double-blind, parallel-group study design was used to compare the antianginal efficacy of bevantolol (200 to 400 mg) and atenolol (50 to 100 mg) each administrated once daily for 8 weeks in 39 patients with chronic stable angina. Assessments were made using 24-hour ambulatory monitoring and treadmill exercise testing performed 22 to 24 hours after the last dose of medication. Both groups were comparable at the end of the placebo phase. In the bevantolol group, exercise time increased from 7.9 +/- 0.7 minutes with placebo to 9.3 +/- 0.7 minutes with bevantolol (mean +/- standard error of the mean) (p less than 0.05). Time to 1 mm ST depression was unaltered. Rest and exercise heart rate decreased (p less than 0.0001 and less than 0.0005, respectively) as did exercise double product (p less than 0.0001). In the atenolol group exercise time increased from 7.1 +/- 0.7 minutes with placebo to 8.2 +/- 0.8 minutes with atenolol (p less than 0.02). Time to 1 mm ST depression increased (p less than 0.005) and rest and exercise heart rate and double product decreased (p less than 0.0001 and less than 0.05, respectively). When within-group differences between placebo and active drug were compared for bevantolol and atenolol, no significant differences were detected. Both drugs were well tolerated and reduced ambulatory heart rate throughout the 24 hours. This study confirms that both bevantolol and atenolol are effective antianginal agents. Bevantolol compares well with atenolol in the treatment of patients with chronic angina, and there was a similar response to exercise testing with the 2 drugs.

Adrenergic beta-Antagonists↗
PubMed1988

Growth in height, weight and skinfold thickness of Bengali boys of Calcutta, India.

This is the first comprehensive growth study of male children of Bengali parentage. The cross-sectional survey was undertaken in an urban high school situated in the north of the Metropolitan City of Calcutta during 1982 and 1983. The sample consisted of 815 healthy Bengali boys aged 7-16 years. In this paper, data on height, weight, and skinfold thicknesses are presented including patterns of change in these physical traits with increasing age. Mean values of height or weight of the boys--not representative for all school-going boys of Calcutta--are distinctly above the national standards given by the Indian Council of Medical Research. They are, however, shorter and lighter than the well-off boys of India but have a similar magnitude of subcutaneous fat on arm. Peak annual incremental growth in height and weight occurs in Bengali boys at 12-13 years and 14-15 years, respectively. This is about one year earlier than in the well-off Indian, British, or American boys.

Adolescent↗
PubMed1987

Molecular cloning and sequencing of a cDNA for olfactory marker protein.

cDNA clones corresponding to mRNA for rat olfactory marker protein (OMP) were isolated from a cDNA library. The library was constructed from olfactory mucosa poly(A)+ RNA enriched for OMP mRNA and cloned into a pBR322-derived plasmid, pMG5. OMP cDNA clones were detected by using a 17-base oligonucleotide probe that contained all 16 possible sequences coding for a known partial amino acid sequence of rat OMP. The identity of these clones was confirmed by hybrid-selected translation and nucleotide sequencing. The sequence of one clone was determined and contained the complete OMP coding region of 486 nucleotides followed by 1630 nucleotides of the 3' untranslated region. The 3' untranslated region included the polyadenylylation signal 16 nucleotides upstream of the poly(A) tail. No other ATG-initiated open reading frame larger than 20 codons was present in register. RNA blot analysis of olfactory mucosa poly(A)+ RNA using this clone as a probe indicated that the level of OMP mRNA, but not its size, declined significantly within a few days following olfactory bulbectomy. OMP mRNA was not detected in 14 nonolfactory rat tissues. Surprisingly, a small amount of OMP mRNA was observed in olfactory bulb. The presence of OMP mRNA in olfactory bulb was confirmed by in vitro translation and immunoprecipitation. These results suggest either that a previously undescribed population of neurons in the olfactory bulb synthesize OMP or that OMP mRNA is transported to the bulb by axonal transport.

Amino Acid Sequence↗
PubMed1987

Alteration in the histochemical profile of steroid dehydrogenases in the uropygial gland of male domestic pigeons following androgen deprivation and testosterone supplement.

Activities of delta 5-3 beta-hydroxysteroid dehydrogenase (3 beta-HSDH) and 17 beta-hydroxysteroid dehydrogenase (17 beta-HSDH)) were histochemically demonstrated in the alveoli of the uropygial glands of male domestic pigeons (Columba livia Gmelin). The level of 3 beta-HSDH (Substrates: pregnenolone and dehydroepiandrosterone) was very low. On the other hand, an intense activity of 17 beta-HSDH was observed in the glandular alveoli of both sexually immature and adult pigeons when testosterone was used as the substrate. In the adult specimens, bilateral castration resulted in a moderate increase of the level of 17 beta-HSDH indicating a faster rate of conversion of testosterone into the weaker androgen, namely, delta 4-androstene-3,17-dione. On the other hand, administration of testosterone propionate (TP), 500 micrograms/bird/day for 15 days in the intact prepubertal and castrated adult pigeons caused a perceptible depletion of 17 beta-HSDH, which may be correlated with the increase in the local concentration of testosterone. Low dose of TP (100 micrograms/day) had no effect. When estradiol-17 beta was used as the substrate for 17 beta-HSDH, there was only a feeble response within the alveoli.

17-Hydroxysteroid Dehydrogenases↗
PubMed1985

Receptor-mediated uptake of asialoganglioside liposomes: sub-cellular distribution of the liposomal marker in isolated liver cell types.

The use of asialo GM1-containing small unilamellar liposome preparations in vivo caused a 2.8-fold increase in the uptake by the liver as compared with the control (neutral) preparations (without asialo GM1). The uptake of negatively charged dicetylphosphate and dipalmitoyl phosphatidic acid-containing small unilamellar liposomes was found to be 1.6-and 1.8-fold respectively higher than that of the neutral preparations. In studies with isolated liver cell types, inhibition of the galactosylated liposome uptake by asialofetuin indicated a possible involvement of hepatic galactose receptors in the recognition of asialo GM1 liposomes by the hepatic parenchymal cells, which in turn were found to be mainly responsible for the enhanced incorporation of these liposomes in the liver. Sub-cellular distribution studies with isolated liver cell types indicated lysosomal localization of the liposomes both in parenchymal and nonparenchymal cells, and it has been proposed that the asialo GM1 liposomes are cointernalized with asialofetuin through a common lysosomal route of ligand internalization.

Animals↗
PubMed1982

Action of oxotremorine on the sub-cellular distribution of glycine in the rat spinal cord.

Intraperitoneal (i.p.) injection of 250 micrograms/kg of oxotremorine (OT) caused a 50% decrease in the glycine content of the synaptosomal-mitochondrial fraction of spinal cord homogenates prepared from rats killed 15 min after treatment. The glycine content of the supernatant fraction was correspondingly raised. In synaptosomes isolated from the spinal cord of OT-treated rats, the decrease in glycine content was 30%. Prior administration of atropine, but not of methylatropine, abolished this effect of OT on synaptosomal glycine content. Eserine exerted a potentiating effect on the action of OT in lowering the glycine content of spinal synaptosomes. Prior administration of L-DOPA, apomorphine, haloperidol, muscarine or mecamylamine had no significant effect on the action of OT on synaptosomal glycine content. OT alone or in combination with eserine, and acetylcholine (ACh) in combination with eserine, did not alter the rate of release of glycine from spinal synaptosomes of untreated rats incubated under appropriate conditions. OT was also without effect on the rate of release of glycine from normal spinal synaptosomes subjected to electrical stimulation, as well as on the eventual glycine content of the synaptosomes. On the basis of the present findings it has been suggested that (i) glycine may be released from Renshaw cells at their synapses with motoneurones in response to the muscarinic action of OT; (ii) dopaminergic modulation may not be involved in the OT-induced glycine release from Renshaw cells; and (iii) excessive release of glycine onto motoneurones may be the causative factor of the akinesia observed in OT-induced experimental Parkinsonism.

Animals↗
PubMed1982

Serine transhydroxymethylase activity in vertebrate retina.

The presence of serine transhydroxymethylase (STHM; EC 2.1.2.1) in crude homogenates of rat, guinea pig and goat retina has been demonstrated. There was a variation in the levels of retinal STHM activity in the three species. Substantial STHM activity was found in all the three retinal preparations in the absence of pyridoxal-5-phosphate in the incubation medium. There was direct correlation (r = 0.995; p less than 0.001) between the STHM activity and the glycine content in rat telencephalon, midbrain, medulla-pons, spinal cord and retina. These findings suggest that STHM is probably an important enzyme for the synthesis of neural glycine in the vertebrate retina.

Animals↗
PubMed1981

Glyoxylate aminotransferase activity in vertebrate retina.

Glyoxylate aminotransferase activity with L-glutamate, L-glutamine and L-alanine as substrates, has been estimated in rat, guinea pig and goat retinae. Enhanced enzyme activity was found in the presence of Triton X-100. The presence of significant aminotransferase activity raises a possibility of glyoxylate as a precursor of glycine in vertebrate retina.

Animals↗