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Biomedical subjects

S Chakraborty

Publications and source records attributed to S Chakraborty.

At least 127 records · Page 7Linked to original sources
PubMed1993

Twinning rate in the Muslim population of West Bengal.

Total birth records for the Bengalee Muslim population (BMP) and the Bengalee Hindu caste population (BHCP) for the period 1980-1988 were 17,720 and 119,107 respectively. Of these, the number of twin pairs were 363 BMP and 1,229 BHCP. These data were obtained from the registers of the following hospitals: Islamia Hospital, NRS Medical College and Hospitals and RG Kar Medical College and Hospitals, Calcutta and Medinipore Sadar Hospital, West Bengal, India. The twinning rates found were 20.48 and 10.57 per thousand deliveries in the BMP and BHCP respectively. The proportion of twins, 0.02048, in the BMP was significantly higher (Z = 12.38, p < or = 0.01) than that in the BHCP, 0.01057. This finding of a higher twinning rate in the BMP is corroborated by the fact that available data on the Muslim population of Srinagar in Kammu and Kashmir, and Lucknow and Kanpur in Uttar Pradesh show higher twinning rates than the other populations of India. This increased twinning rate may be due to the greater amount of inbreeding in the BMP.

Asian People↗
PubMed1993

Randomized clinical trial of furazolidone for typhoid fever in children.

The efficacy of furazolidone and chloramphenicol was compared in a randomized trial involving 133 children with bacteriologically confirmed typhoid fever. Sixty-five children were randomized to receive furazolidone, 7.5 mg/kg/day, and 68 children to receive chloramphenicol, 75 mg/kg/day. Both drugs were administered orally. The clinical characteristics of the two treatment groups were comparable on admission. All the strains of Salmonella typhi isolated from the furazolidone group were susceptible to furazolidone. However, of the 68 strains of S. typhi isolated from the chloramphenicol group, 10 were susceptible and 58 were resistant to chloramphenicol. Clinical and bacteriologic cure was observed in 56 (86.2%) children treated with furazolidone and in 35 (51.5%) children given chloramphenicol who were infected with S. typhi strains, irrespective of susceptibility pattern (P = 0.00003). Cure was achieved in 86.2% of furazolidone recipients and 90.0% of chloramphenicol recipients who were infected with strains of S. typhi susceptible to both drugs (P = 0.6). The difference in cure rate was statistically significant (P = 0.000003) when the two treatment groups infected with furazolidone-susceptible but chloramphenicol-resistant strains of S. typhi were compared. There was no relapse or carriers in either of the groups. Furazolidone appears to be a satisfactory alternative to chloramphenicol in the treatment of typhoid fever caused by chloramphenicol-resistant strains of S. typhi.

Carrier State↗
PubMed1993

Demonstration of acid-fast bacilli in tissues and evaluation of atypical tuberculous lesions.

A study was conducted with tissue sections of 60 different suspected tuberculous lesions, obtained by biopsy from 60 patients of different age groups. The tissue sections were fixed with formol saline and stained with haematoxylin and eosin and Ziehl-Neelsen stain. Histological picture of tuberculosis and presence of acid-fast bacilli were studied. Out of 60, 39 sections showed typical tuberculous lesions. Remaining 21 sections presented atypical lesions. Of those 39 typical lesions 17(43%) showed presence of acid-fast bacilli. Among atypical lesions 10(47%) showed presence of acid-fast bacilli. Thus it may be stated that diagnosis of tuberculosis is not confirmed unless acid-fast bacilli is demonstrated in the lesions. Tuberculosis in substantial number of cases produces non-granulomatous atypical lesions, so non-specific inflammation and granulation tissue in histology need Ziehl-Neelsen staining and careful search for acid-fast bacilli should be made to exclude tuberculosis where the disease is common.

Adolescent↗
PubMed1993

Effect of vasodilator therapy on mortality in chronic congestive heart failure.

We compared the effects of Hydralazine and Isosorbide dinitrate (ISDN) with those of an angiotensin-converting-enzyme inhibitor, captopril on mortality in patients with chronic congestive heart failure (NYHA class III and IV). Patients receiving conventional treatment with digoxin and diuretics were randomly assigned to receive either placebo (n = 51), hydralazine-ISDN. (n = 50) or captopril (n = 52) in a double blind trial. At the end of 6 months there were 14 deaths in the placebo group (27.4%) as compared with 11 deaths in the hydralazine-ISDN group (22%)--a mortality reduction of 20% (P > 0.05) and 10 deaths in the captopril group (19.2%)--a mortality reduction of 30% (p > 0.05). At the end of one year, mortality was 50%, 42% and 30% in the placebo, hydralazine-ISDN and captopril groups respectively with a mortality reduction of 16% in the hydralazine-ISDN group (p > 0.05) and 40% in the captopril group (p < 0.05) compared to the placebo group. The mortality reduction was mainly due to reduction in deaths attributed to progressive heart failure. The data suggests that the addition of captopril to conventional treatment significantly reduces mortality in patients with severe congestive heart failure. Hydralazine-isorobide dinitrate also reduced mortality but statistically this was not significant.

Adult↗
PubMed1991

Base- and sequence-dependent binding of aristololactam beta-D-glucoside to deoxyribonucleic acid.

The dependence on base-pair composition and sequence specificity of the (aristololactam beta-D-glucoside)-DNA interaction was examined by spectrophotometric, spectrofluorometric, spectropolarimetric, thermal melting, thermodynamic, and viscometric studies. Binding of this alkaloid to various natural and synthetic DNAs was dependent upon the base composition and sequences of DNA. The binding parameters obtained from spectrophotometric analysis, according to an excluded-site model, indicated a relatively high affinity of the alkaloid binding to GC-rich DNA and alternating GC polymer. This affinity was further evidenced by the quenching of fluorescence intensity, decrease in quantum yield, and perturbations in circular dichroic spectrum. The alkaloid stabilized all DNAs against thermal denaturation. The temperature dependence of the binding constants was used to estimate the thermodynamic parameters involved in the complex formation of the alkaloid with various DNAs. The negative enthalpy and entropy change increased with increasing GC content of DNA and also compensated one another to produce a relatively small Gibbs free energy change. Viscometric studies showed that in the strong binding region the increase of contour length of DNA depended strongly on its base composition and sequence of bases, being larger for GC-rich DNA and alternating GC polymer. On the basis of these observations, it is concluded that the alkaloid binds to DNA by a mechanism of intercalation and exhibits considerable specificity toward alternating GC polymer.

Alkaloids↗
PubMed1991

Antifertility effect of chronically administered Malviscus conzattii flower extract on fertility of male rats.

Quantitative evaluation of different varieties of germ cells at stage VII of the cycle, namely type A spermatogonia, pre-leptotene spermatocytes, mid-pachytene spermatocytes, step 7 and step 19 spermatids, along with radio-immunoassay of serum gonadotrophins (LH and FSH), testosterone and testicular testosterone were performed in rats of Wistar strain following treatment with methanolic extract of flowers of Malvaviscus conzattii (MVC) at a dose level of 800 mg/kg b.w. for 30 consecutive days. The treatment period just exceeds two cycles of the seminiferous epithelium of the Wistar strain rats (one cycle is 13.2 days). Reduction of step 7 and 19 spermatids at stage VII were observed. Significant reduction in serum concentration of LH and testosterone were observed three and four weeks after treatment. Testicular testosterone was also reduced. No distinct change in serum FSH concentration was recorded. The results indicate that the extract may have an inhibitory influence on gonadotrophin release which may be held responsible for the decline in testosterone production, leading to change in spermatogenesis caused by the MVC extract. Replacement with hCG along with MVC prevented degeneration of step 7 and step 19 spermatids, and enhanced testosterone production support the same idea.

Animals↗
PubMed1991

A method for using low-temperature embedding media for electron microscopy of cells grown on microporous supports.

Attempts were made to embed Madin-Darby canine kidney (MDCK) cells grown on nitrocellulose microporous supports in Lowicryl, a medium designed for the retention of antigenicity for electron microscopic immunocytochemical studies. It was found that the membrane fragmented during the prescribed embedding procedure leading to loss of the cell sample. This necessitated the formulation of a new combination of fixative and dehydration agents which would allow: (i) preservation of membrane and cellular integrity; (ii) infiltration and embedding in Lowicryl; and (iii) detection of a specific antigen in thin sections. The cellular monolayer and organelle profiles were best preserved with glutaraldehyde fixation at room temperature followed by ethanol dehydration. Since the latter was carried out at temperatures attainable with an ice-salt bath, there was no need for a special ultralow-temperature apparatus. This procedure was applied to a MDCK cell clone that consisted of stable secretors of human growth hormone (hGH), as a result of being transfected with a plasmid containing the hGH gene. Thus, it was demonstrated that hGH could be detected by immunogold labeling of thin sections and localized to specific cellular structures. The procedure developed in this report is applicable to cells grown on two other supports and may be extended further.

Animals↗
PubMed1991

Short term effect of diltiazem on portal hypertension in patients with non-cirrhotic portal fibrosis.

Fourteen patients of non-cirrhotic portal fibrosis (NCPF) with portal hypertension were put on oral diltiazem hydrochloride (90 mg/day) or placebo on a prospective, randomised, single blind basis for 15 days. Predrug hemodynamic and biochemical status were similar in both groups. Diltiazem produced significant reduction (p less than 0.001) in mean intrasplenic pressure: from 41.88 (SD +/- 6.18) to 21.5 (+/- 7.91) cm of normal saline as against 45.56 (+/- 9.45) to 43.33 (+/- 8.27) in the placebo group. Mean arterial pressure (MAP), heart rate and cardiac output (CO) did not change in either group. Thus, the calcium channel blocker diltiazem reduces portal pressure in patients with NCPF, independent of reduction in MAP and CO; this is advantageous in situations where compromised cardiac hemodynamics may prove deleterious.

Adult↗
PubMed1990

Thermodynamics of the interaction of aristololactam-beta-D-glucoside with DNA. Ionic strength dependence of enthalpy and entropy.

The interaction of aristololactam-beta-D-glucoside with calf thymus DNA has been studied by measuring the changes in the absorbance of the alkaloid over a wide range of temperatures and sodium chloride concentrations. The binding parameters obtained are best fit by the neighbour exclusion model. The salt and temperature dependence of the binding constants are used to estimate the thermodynamic parameters involved in the interaction of the alkaloid with DNA. It is observed that aristololactam-beta-D-glucoside binding to DNA is an exothermic process over the entire range of salt and temperature, and the estimated values of enthalpy and entropy change are strongly dependent on the ionic strength of the solution. The enthalpy and entropy changes compensate one another to produce a relatively small Gibbs' free energy change. The possibility that aristololactam-beta-D-glucoside exists as a monovalent cation at neutral pH and the possible molecular contribution to the enthalpy and entropy changes of the aristololactam-beta-D-glucoside-DNA complex are discussed.

Alkaloids↗
PubMed1990

19F NMR studies on 8-fluoroflavins and 8-fluoro flavoproteins.

The 19F NMR spectra of the oxidized and reduced forms of 8-fluororiboflavin, 8-fluoro-FAD, and the 8-fluoroflavin-reconstituted flavoproteins flavodoxin, riboflavin binding protein, D-amino acid oxidase, p-hydroxybenzoate hydroxylase, Old Yellow Enzyme, anthranilate hydroxylase, general acyl-CoA dehydrogenase, glucose oxidase, and L-lactate oxidase were measured. For the proteins studied the oxidized resonances appeared over a 10.1-ppm range, while the reduced resonances were spread over 10.3 ppm. Reduction caused an upfield shift of about 27 ppm for the free 8-fluoroflavins and most of the 8-fluoro flavoproteins. The notable exception was 8-fluoro-FMN flavodoxin, which was shifted 37.6 ppm, indicating an unusually high electron density in the benzene ring. Ligand binding to the oxidized 8-fluoro flavoproteins caused either upfield or downfield shifts of 1.5-5 ppm, depending on the protein/ligand combination. The 8-fluoro-FAD anthranilate hydroxylase resonance was shifted downfield and split into two peaks in the presence of anthranilate. The 8-fluoro-FMN Old Yellow Enzyme resonance was shifted upfield upon complexation with charge-transfer-forming, para-substituted phenolates. The upfield shift increased from less than 1 to 5 ppm as the electron-donating capacity of the phenolate increased. Complexation of native Old Yellow Enzyme with 2,4-difluorophenol caused the fluorine resonances of the ligand to shift and split into two pairs of signals. Each pair of signals was associated with a different isozyme of Old Yellow Enzyme.

Acyl-CoA Dehydrogenases↗
PubMed1990

Glucose oxidase from Aspergillus niger. Cloning, gene sequence, secretion from Saccharomyces cerevisiae and kinetic analysis of a yeast-derived enzyme.

The gene for Aspergillus niger glucose oxidase (EC 1.1.3.4) has been cloned from both cDNA and genomic libraries using oligonucleotide probes derived from the amino acid sequences of peptide fragments of the enzyme. The mature enzyme consists of 583 amino acids and is preceded by a 22-amino acid presequence. No intervening sequences are found within the coding region. The enzyme contains 3 cysteine residues and 8 potential sites for N-linked glycosylation. The protein shows 26% identity with alcohol oxidase of Hansenuela polymorpha, and the N terminus has a sequence homologous with the AMP-binding region of other flavoenzymes such as p-hydroxybenzoate hydroxylase and glutathione reductase. Recombinant yeast expression plasmids have been constructed containing a hybrid yeast alcohol dehydrogenase II-glyceraldehyde-3-phosphate dehydrogenase promoter, either the yeast alpha-factor pheromone leader or the glucose oxidase presequence, and the mature glucose oxidase coding sequence. When transformed into yeast, these plasmids direct the synthesis and secretion of between 75 and 400 micrograms/ml of active glucose oxidase. Analysis of the yeast-derived enzymes shows that they are of comparable specific activity and have more extensive N-linked glycosylation than the A. niger protein.

Amino Acid Sequence↗
PubMed1990

Krabbe disease locus mapped to chromosome 14 by genetic linkage.

Using genetic linkage we have localized the gene coding for galactocerebrosidase (GALC) to human chromosome 14. Patients with Krabbe disease and their family members were assayed for GALC activity in leukocytes or fibroblasts and were classified as affected, carrier, noncarrier, or unknown. Polymorphic DNA markers from chromosome 14 demonstrated a multipoint LOD score of 3.40 with GALC located 13 cM centromere distal to CRI-C70 (D14S24). This finding is consistent with the location of the mouse twitcher mutation (a model of human GALC deficiency) on chromosome 12, which has substantial homology to human chromosome 14. Our data do not support a previous report's localization of GALC to chromosome 17.

Chromosomes, Human, Pair 14↗
PubMed1990

Clinical features & prognostic indicators of Japanese encephalitis in children in Lucknow (India).

This communication reports the clinical features of 92 children with Japanese encephalitis diagnosed on the basis of viral isolation from brain or cerebrospinal fluid and/or a 4-fold or higher rise in antibody titre in paired sera by haemagglutination inhibition (HI) test, followed by detection of specific IgM HI antibody. More than a third of the patients (38%) were from urban areas. A high incidence of fever (94.5%), coma (100%) and convulsions (84.7%) was seen. Focal neurological deficit was found in 29.3 per cent of patients and pleocytosis in the cerebrospinal fluid in 32.3 per cent. An extrapyramidal syndrome developed in 21.3 per cent patients during the convalescent stage. Thirty four (36.9%) patients died while in hospital. Mortality was significantly related to a short prodromal stage, deep coma, abnormalities in tone and breathing and decerebrate posturing. Japanese encephalitis represents a severe disease in children with a high early mortality.

Child↗
PubMed1989

Aristololactam-beta-D-glucoside. A new DNA binding monofunctional intercalating alkaloid.

The binding of aristololactam-beta-D-glucoside to DNA is characterized by hypochromism and bathochromism in the absorption band, quenching of the fluorescence intensity, increase in the positive and negative ellipticity of DNA, enhancement of thermal transition temperature, sign and magnitude of thermodynamic parameters, increase of the contour length of sonicated rod-like DNA and induction of the unwinding-rewinding process of covalently closed superhelical DNA. Binding parameters determined from absorbance and fluorescence titration by Scatchard analysis, according to an excluded-site model, indicate a very high affinity towards DNA. The binding of the alkaloid is an exothermic process with Gibbs free energy of -7.4 kcal/mol, van't Hoff enthalpy of -13.8 kcal/mol and entropy of -21.5 cal/degree/mol at 25 degrees. On the basis of these observations it is concluded that aristololactam-beta-D-glucoside binds to DNA by a mechanism of intercalation.

Alkaloids↗
PubMed1989

Change in the ploidy state of rat liver cells during chemical hepatocarcinogenesis and its relationship to the increased expression of alpha-fetoprotein.

The DNA content and ploidy state of cells isolated from the livers of rats exposed to the carcinogen 3'-methyl-4-dimethylaminoazobenzene for 10 and 20 weeks, as determined by flow cytometry, were correlated with the development of oval cells in the livers of treated animals and with serum levels of the oncoprotein alpha-fetoprotein (AFP). The study revealed that there was initially a steady rise in the AFP levels found in the carcinogen treated rats. Associated with this increase was a change in the ploidy pattern of the liver from an approximately equal mixture of tetraploid and diploid cells to a predominantly diploid state. Histologically, there was an increase in the number of oval cells during carcinogen treatment, and when stained immunohistochemically for AFP, these cells were positive. We conclude that the changing state of the diploid and tetraploid cell populations is due to the proliferation of oval cells and that these cells are responsible for the initial increase of serum AFP. The maintenance of the diploid population of cells at later periods of the study is a reflection of the persistence of a new cell type, possibly derived from oval cells. The effect of 3'-methyl-4-dimethylaminoazobenzene was not reversed if the animals were withdrawn from the diet at 10 weeks. In addition, in the cases of hepatocellular carcinoma that were found, a population of cells was detected by flow cytometry that contained altered DNA.

Animals↗