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Biomedical subjects

S K Bhattacharya

Publications and source records attributed to S K Bhattacharya.

At least 109 records · Page 6Linked to original sources
PubMed2002

Effect of poly herbal formulation, EuMil, on neurochemical perturbations induced by chronic stress.

EuMil, a polyherbal formulation consisting of standardised extracts of Withania somnifera (L) Dunal, Ocimum sanctum L, Asparagus racemosus Wilid and Emblica officinalis Gaertn., is used as an anti-stress agent to attenuate the various aspects of stress related disorders. In the present study, the neurochemical mechanisms underlying the anti-stress activity of EuMil were evaluated by measuring the rat brain monoamine neurotransmitter levels and tribulin activity. Chronic electroshock stress (14 days) significantly decreased the nor-adrenaline (NA) and dopamine (DA) levels in frontal Cortex, pons-medulla, hypothalamus, hippocampus and striatal, hypothalamal region, respectively, and increased the 5-hydroxytryptamine (5HT) level in frontal cortex, pons medulla, hypothalamus and hippocampus. Chronic stress, also increased the rat brain tribulin activity. EuMil (100 mg/kg, p.o., 14 days) treatment normalized the perturbed regional NA, DA, 5HT concentrations, induced by chronic stress. EuMil also significantly attenuated the stress-induced increase in the rat brain tribulin activity. The amelioration of chronic stress-induced neurochemical perturbations by EuMil explains the neurochemical mechanisms underlying the observed putative anti-stress activity of the product.

Animals↗
PubMed2002

Bacteriological profile of cholera in Tamil Nadu (1980-2001).

BACKGROUND & OBJECTIVE: In addition to Vibrio cholerae O1, a recently emerged non-O1 serotype, V. cholerae O139 has also been found to be responsible for epidemics of cholera. In the context of the changing etiology of cholera, the occurrence of different serotypes, biotypes and phage types of V. cholerae in Tamil Nadu is presented. METHODS: Between 1980 and 2001, 26,502 stool/rectal swabs from patients suspected to have cholera were processed for the presence of V. cholerae at the King Institute of Preventive Medicine, Chennai (Madras), Tamil Nadu. Serotypes, biotypes and phage types (Basu & Mukerjee and new phage typing method) of the isolates were determined. Antimicrobial susceptibility determination was included from 1997 onwards. RESULTS: Of the 26,502 stool/rectal swabs tested, 6035 (22.8%) specimens yielded V. cholerae. 4,046 (67%) of them were O1 serotype; followed by 1529 (25.3%) O139 serotype and 448 (7.4%) non-O1 serotypes other than O139 were encountered. Twelve specimens yielded rough strains of V. cholerae. All V. cholerae O1 were the biotype ElTor and the predominant serotype was Ogawa (95.9%). After the initial explosive epidemic by O139 serotype in late 1992 and early 1993 occurrence of this serotype had declined. Resurgence of this new serotype was observed in 1997. O1 domination was observed during 1995 and 1996. The new phage typing scheme for V. cholerae O1 was able to differentiate the isolates into 22 types, type 27 (68.2%) being the predominant one followed by type 26 (12.3%). In Basu & Mukerjee scheme, the isolates were clustered between two types--type 2 (34%) and type 4 (61%). Further, about 5 per cent of them were untypeable. All but a few of the isolates irrespective of serotype, were susceptible to chloramphenicol, tetracycline, gentamicin and ciprofloxacin. 97 per cent of the O1 strains and 48.9 per cent of the O139 strains were resistant to cotrimoxazole. INTERPRETATION & CONCLUSION: V. cholerae O139 might have the ability to survive during interepidemic periods. Both V. cholerae O1 and O139--the two serotypes with epidemic potential seem to be firmly established in this region. This situation warrants constant surveillance.

Animals↗
PubMed2001

Correlations between osteocalcin content, degree of mineralization, and mechanical properties of C. carpio rib bone.

Osteocalcin is one of the most abundant noncollagenous proteins in bone. It is strongly associated with the mineral phase of bone, and has long been associated as a marker of bone turnover. However, its relationship to bone composition, strength, and structure is unclear. Carp rib bone is an excellent model for the study, because osteocalcin represents almost 60% of the total extractable noncollagenous proteins found in it. Because of the abundance of osteocalcin relative to other extractable proteins, any changes in the properties of carp rib bone would be more likely influenced by the osteocalcin concentration. To test the hypotheses that the concentration of osteocalcin is reflected in other properties of bone, the correlations between the osteocalcin concentration and the mineral content, microstructural properties, and physical characteristics of the bone mineral crystals were determined utilizing radioimmunoassay (RIA), spectrophotometry, nanoindentation, and small-angle X-ray scattering (SAXS) techniques, respectively. Osteocalcin concentration was found to be correlated to the molar Ca/P ratio and inversely correlated to the elastic modulus and hardness in the longitudinal plane. This study provides evidence for a putative relationship between the concentration of osteocalcin and the microstructural mechanical properties of bone. Correlations were also found between the mechanical properties in the longitudinal plane and both the phosphate content and the molar Ca/P ratio. However, no relationships could be identified between osteocalcin concentration and several parameters of bone crystals, as determined by SAXS.

Animals↗
PubMed2001

The evolution of human group B rotaviruses.

The largest reported rotavirus epidemic affected well over a million people in China during 1982-83 and was caused by the adult diarrhoea rotavirus (ADRV), a serogroup B rotavirus. However, ADRV has not been reported outside China since the last recorded small outbreak there in 1987. Here we present evidence that offers an explanation for the sudden appearance and disappearance of the epidemic ADRV strain.

China↗
PubMed2001

Sequence analysis of genes encoding structural and nonstructural proteins of a human group B rotavirus detected in Calcutta, India.

Nucleotide sequences of RNA segments encoding structural proteins(VP4, VP6, and VP7) and nonstructural proteins(NSP1 and NSP3) of a human group B rotavirus CAL-1, which was detected in Calcutta, India, were determined and their relatedness with cognate genes of other group B rotaviruses was analyzed. The CAL-1 genes showed generally high sequence identities (more than 90%) to those of human group B rotavirus, adult diarrheal rotavirus (ADRV) in China, while identities with bovine, murine, and ovine viruses were considerably lower (58-73%). Among RNA segments analyzed, sequence identity of the VP6 gene was relatively high compared with other gene segments. In the CAL-1 VP7 sequence, many characteristics were shared by ADRV, but not by other animal group B rotaviruses. In contrast, VP4 and NSP3 of CAL-1 were single amino acid and 23 amino acids longer than those of ADRV strain, respectively, due to differences of a few nucleotides. These findings suggested that human group B rotaviruses CAL-1 and ADRV might have originated from a common ancestral virus distinct from animal group B rotaviruses reported so far, while some notable sequence differences indicated the distinct nature of these viruses.

3' Untranslated Regions↗
PubMed2001

Molecular characterization of the VP7 gene of Rotavirus isolated from a clinical sample of Calcutta, India.

The gene coding for outer capsid protein, VP7 of rotaviruses detected among the children suffering from watery diarrhea in the eastern part of India was studied. The full length gene, coding for VP7 was synthesized from a local strain, WD33, by combined reverse transcriptase-polymerase chain reaction. A total of 42 fecal RNA out of 93 rotavirus-positive samples hybridized with this DNA, indicating the prevalence of this strain in the community. Comparison of the nucleotide and deduced amino acid sequence with the VP7 gene of other serotypes revealed that the local strain,WD33, resembled closely with G1 serotype, the homology being 94 and 97%, respectively. Multiplex PCR using the specific oligonucleotide primers also amplified the G1 specific DNA fragment. The overall change of 16 amino acids was noticed when compared with G1 specific prototype Wa strain of which nine amino acids are within the neutralization domain. However, the phylogenetic tree constructed by comparing the G1 strains from different countries demonstrated that this strain WD33 clustered as a distinct sub-lineage of lineage IV and not with Wa strain, that clustered with lineage III.

Amino Acid Sequence↗
PubMed2001

Anti-oxidant effect of Withania somnifera glycowithanolides in chronic footshock stress-induced perturbations of oxidative free radical scavenging enzymes and lipid peroxidation in rat frontal cortex and striatum.

The antioxidant activity of Withania somnifera (WS) glycowithanolides was assessed in chronic footshock stress induced changes in rat brain frontal cortex and striatum. The stress procedure, given once daily for 21 days, induced an increase in superoxide dismutase (SOD) and lipid peroxidation (LPO) activity, with concomitant decrease in catalase (CAT) and glutathione peroxidase (GPX) activities in both the brain regions. WS glycowithanolides (WSG), administered orally 1 h prior to the stress procedure for 21 days, in the doses of 10, 20 and 50 mg/kg, induced a dose-related reversal of the stress effects. Thus, WSG tended to normalise the augmented SOD and LPO activities and enhanced the activities of CAT and GPX. The results indicate that, at least part of chronic stress-induced pathology may be due to oxidative stress, which is mitigated by WSG, lending support to the clinical use of the plant as an antistress adaptogen.

Administration, Oral↗
PubMed2001

The distribution of osteocalcin, degree of mineralization, and mechanical properties along the length of Cyprinus carpio rib bone.

This study examined the spatial distribution of selected biochemical and mechanical properties along the length of carp rib bone. Carp rib bone was chosen because of its unusually high osteocalcin content relative to other extractable proteins. The amount of osteocalcin was significantly lower (p<0.01) at the most distal section, relative to all other sections. The amount of phosphate (p<0.05) and the elastic modulus in the longitudinal plane (p<0.0001) were found to be significantly higher in the most distal section, relative to the most proximal section. There was no significant difference in the calcium distribution, molar Ca/P ratio, or elastic modulus in the transverse plane. It was speculated that the distal section contains less mature bone. The methods illustrate the potential usefulness of nanoindentation to characterize the mechanical properties of bone, relative to its biochemical composition.

Journal Article↗
PubMed2001

Sensitivity and performance characteristics of a direct PCR with stool samples in comparison to conventional techniques for diagnosis of Shigella and enteroinvasive Escherichia coli infection in children with acute diarrhoea in Calcutta, India.

As the sensitivity of the conventional techniques for identifying Shigella spp. and enteroinvasive Escherichia coli (EIEC) causing dysentery cases is low, a PCR assay was evaluated in this study. Analytical sensitivity (2 x 10(2) cfu) of the PCR technique was obtained by artificially spiking negative stool samples with a standard strain of S. flexneri type 2, then determining the detection limit. Specificity (100%) of the method was determined by testing a number of known Shigella and EIEC strains and organisms other than Shigella spp. A total of 300 stool samples collected from children with acute diarrhoea was plated on to two selective agar media after enrichment in Luria broth. Shigella spp. were isolated from 7.7% (23 of 300) and EIEC from 1% (3 of 300) patients. All enriched stool samples were subjected to PCR to amplify the target sequence of invasive plasmid antigen (ipa)H locus, a multicopy element found on the chromosome and invasion plasmid. The stool PCR was positive in 24 of the 26 culture-positive and in 22 culture-negative stools, thus detecting the presence of Shigella spp. or EIEC in 15.3% (46 of 300) of diarrhoea cases. When an ial probe was used for colony hybridistion with enriched stool cultures blotted on to membranes, 9.6% (29 of 300) of dysentery cases were identified as being caused by Shigella spp. or EIEC. Thus the sensitivity of enriched stool culture, colony hybridisation and enriched stool PCR was found to be 54%, 60% and 96%, respectively, when each of the methods was compared to the total microbiologically confirmed cases of dysentery. It was also observed that only 38% (48 of 126) of acute bloody dysentery cases actually had shigella or EIEC infection, as confirmed by laboratory methods. Moreover, this PCR assay could identify a number of untypable Shigella strains (Sh OUT), which would have remained undiagnosed had this assay not been used.

Acute Disease↗
PubMed2001

Immunomodulatory role of interleukin-10 in visceral leishmaniasis: defective activation of protein kinase C-mediated signal transduction events.

Leishmania donovani, an intracellular protozoan parasite, challenges host defense mechanisms by impairing the signal transduction of macrophages. In this study we investigated whether interleukin-10 (IL-10)-mediated alteration of signaling events in a murine model of visceral leishmaniasis is associated with macrophage deactivation. Primary in vitro cultures of macrophages infected with leishmanial parasites markedly elevated the endogenous release of IL-10. Treatment with either L. donovani or recombinant IL-10 (rIL-10) inhibited both the activity and expression of the Ca2+-dependent protein kinase C (PKC) isoform. However, preincubation with neutralizing anti-IL-10 monoclonal antibody (MAb) restored the PKC activity in the parasitized macrophage. Furthermore, we observed that coincubation of macrophages with rIL-10 and L. donovani increased the intracellular parasite burden, which was abrogated by anti-IL-10 MAb. Consistent with these observations, generation of superoxide (O2-) and nitric oxide and the release of murine tumor necrosis factor-alpha were attenuated in response to L. donovani or rIL-10 treatment. On the other hand, preincubation of the infected macrophages with neutralizing anti-IL-10 MAb significantly blocked the inhibition of nitric oxide and murine tumor necrosis factor-alpha release by the infected macrophages. These findings imply that infection with L. donovani induces endogenous secretion of murine IL-10, which in turn facilitates the intracellular survival of the protozoan and orchestrates several immunomodulatory roles via selective impairment of PKC-mediated signal transduction.

Adjuvants, Immunologic↗
PubMed2001

Concomitant infection of enterotoxigenic Escherichia coli in an outbreak of cholera caused by Vibrio cholerae O1 and O139 in Ahmedabad, India.

In Ahmedabad, a major city in the state of Gujarat, India, an outbreak of acute secretory diarrhea caused by Vibrio cholerae O1 Ogawa El Tor, V. cholerae O139, and multiple serotypes of enterotoxigenic Escherichia coli (ETEC) occurred in January 2000. All of the representative V. cholerae O1 and O139 isolates examined harbored the ctxA gene (encoding the A subunit of cholera toxin) and the El Tor variant of the tcpA gene (encoding toxin-coregulated pilus). ETEC isolates of different serotypes were positive for the elt gene, encoding heat-labile enterotoxin. To further understand the molecular characteristics of the pathogens, representative isolates were examined by ribotyping and pulsed-field gel electrophoresis (PFGE). Ribotyping showed that the isolates of V. cholerae O1 Ogawa exhibited a pattern identical to that of the prevailing clone of O1 in areas where cholera is endemic in India, and all of the O139 isolates were identical to the BII clone of V. cholerae O139. PFGE of the representative O1 Ogawa isolates exhibited an identical pattern, comparable to the H pattern of the new clone of O1 reported in Calcutta, India. PFGE analysis of the V. cholerae O139 isolates showed identical patterns, but these differed from the PFGE patterns of O139 isolates reported during 1992 to 1997 in Calcutta. ETEC isolates showed genetic heterogeneity among isolates belonging to the same serotype, although the identical PFGE pattern was also observed among ETEC isolates of different serotypes. Antibiograms of the isolates were unusual, because all of the O139 isolates were resistant to nalidixic acid. Likewise, all of the E. coli isolates showed resistance to ciprofloxacin, norfloxacin, and nalidixic acid. This is a unique outbreak, and we believe that it is the first in which V. cholerae and ETEC were concomitantly involved.

Anti-Bacterial Agents↗
PubMed2001

Double blind, randomised controlled clinical trial of hypo-osmolar oral rehydration salt solution in dehydrating acute diarrhoea in severely malnourished (marasmic) children.

AIMS: To compare the clinical efficacy of hypo-osmolar oral rehydration salt (ORS) solution (224 mmol/l) and standard ORS solution (311 mmol/l) in severely malnourished (marasmic) children having less than 60% Harvard standard weight for age with dehydrating acute watery diarrhoea. METHODS: In a double blind, randomised, controlled trial, 64 children aged 6-48 months were randomly assigned standard (n = 32) or hypo-osmolar ORS (n = 32). RESULTS: Stool output (52.3 v 96.6 g/kg/day), duration of diarrhoea (41.5 v 66.4 hours), intake of ORS (111.5 v 168.9 ml/kg/day), and fluid intake (214.6 v 278.3 ml/kg/day) were significantly less in the hypo-osmolar group than in the standard ORS group. Percentage of weight gain on recovery in the hypo-osmolar group was also significantly less (4.3 v 5.4% of admission weight) than in the standard ORS group. A total of 29 (91%) children in the standard ORS group and 32 (100%) children in the hypo-osmolar group recovered within five days of initiation of therapy. Mean serum sodium and potassium concentrations on recovery were within the normal range in both groups. CONCLUSION: Our findings suggest that hypo-osmolar ORS has beneficial effects on the clinical course of dehydrating acute watery diarrhoea in severely malnourished (marasmic) children. Furthermore, children did not become hyponatraemic after receiving hypo-osmolar ORS.

Child, Preschool↗
PubMed2001

Rise in free intracellular calcium in HeLa cells infected with aggregative Klebsiella pneumoniae strains isolated from cases of diarrhoea.

BACKGROUND & OBJECTIVES: Klebsiella pneumoniae strains occasionally cause diarrhoea in humans. This study was done to determine the involvement of calcium in the pathogenesis of aggregative K. pneumoniae strains. METHODS: A total of nine strains of K. pneumoniae were tested for adherence assay in HeLa cell line. A representative strain CO-1215 was used for [Ca2+]i study using Fura-2 fluorescence. RESULTS: Infection of cultured HeLa cells with aggregative K. pneumoniae strain resulted in five-fold elevation of intracellular level of free calcium ([Ca2+]i) with maximum Ca2+ influx at 3 h after bacterial infection. Chelation of extracellular Ca2+ with [ethylenebis(oxyethylenenitrile)] tetraacetic acid and suspension of cells in Ca2+ free buffer suggested that the rise of Ca2+ in aggregative K. pneumoniae infected HeLa cells was due to influx of Ca2+ from extracellular medium. INTERPRETATION & CONCLUSIONS: This study showed aggregative adherence in HeLa cells and this adherence leads to influx of extracellular Ca2+. The unrestricted passage of calcium ions across cell membranes could cause phosphorylation of proteins involved in ion transport across the membrane, which could result in secretory diarrhoea. Further work is in progress to study the enterotoxicity of these strains in an in vitro rabbit intestinal model.

Calcium↗
PubMed2001

Neurochemical studies on Indian Hypericum perforatum L.

The effect of acute administration of 50% standardised ethanolic extract of Indian Hypericum perforatum (IHp) was studied on the rat brain concentrations of monoamines and their metabolites in five different brain regions, viz. hypothalamus, hippocampus, striatum, pons-medulla and frontal cortex by a HPLC technique. IHp extract was administered at the doses of 50 and 200 mg/kg, p.o. and the brain monoamines were assayed after 30 min of the treatment. IHp treatment significantly decreased the levels of serotonin (5-HT) and its metabolite 5-hydroxy indole acetic acid (5-HIAA) and 5-HT turnover in all the brain regions assayed. On the other hand, IHp treatment significantly augmented the levels of norepinephrine (NE) and its metabolite methylhydroxy phenyl glycol (MHPG) and NE turnover in all the brain regions studied. Similarly, the levels of dopamine (DA) were also significantly augmented in the hypothalamus, striatum and frontal cortex. Likewise, the levels of dihydroxyphenyl acetic acid (DOPAC), the major metabolite of DA, were also increased in these brain areas. Pharmacological studies with IHp extract have shown two major behavioural actions, namely, anxiolytic and antidepressant effects. The present findings tend to rationalise these observations, reduced 5-HT activity being consonant with anxiolytic and increased NA and DA activity being consonant with antidepressant action.

Animals↗
PubMed2001

Anti-inflammatory and analgesic activity of Indian Hypericum perforatum L.

A standardised 50% aqueous ethanolic extract of the Indian variety of Hypericum perforatum (IHp) was examined for its putative anti-inflammatory and analgesic activity at the doses of 100 and 200 mg/kg, po. The experimental paradigms used were carrageenan induced pedal edema and cotton pellet induced granuloma for anti-inflammatory activity, whereas the tail flick, hot plate and acetic acid induced writhing methods were used to asses analgesic activity. Indomethacin (20 mg/kg, ip) was used as the standard anti-inflammatory drug. Pentazocine (10 mg/kg, ip) and aspirin (25 mg/kg, ip), both clinically used analgesics, were used as standard analgesics for comparison. IHp extract showed significant anti-inflammatory and analgesic activity at both dose levels, in all the paradigms used. Additionally, IHp potentiated the anti-inflammatory activity of indomethacin and analgesic activities of pentazocine and aspirin.

Analgesics↗
PubMed2001

Anti-stress activity of Indian Hypericum perforatum L.

Indian Hypericum perforatum (IHp) was investigated on a 14-day mild, unpredictable and inescapable foot shock stress (FSS) induced perturbations in behaviour (depression), suppressed male sexual behaviour and cognitive dysfunction in albino rats. Gastric ulceration, and adrenal gland and spleen weights, were also used as the stress indices. Panax ginseng (PG) was used as the standard adaptogenic agent for comparison. FSS induced marked gastric ulceration, significant increase in adrenal gland weight with concomitant decrease in spleen weight. Chronic stress also suppressed male sexual behaviour, induced behavioural depression (Porsolt's swim despair test and learned helplessness test) and cognitive dysfunction (attenuated retention of learning in active and passive avoidance tests). All these FSS induced perturbations were attenuated dose dependently by IHp (100 and 200 mg/kg, po) and PG (100 mg/kg, po). The results indicate that IHp has significant anti-stress activity, qualitatively comparable to PG, against a variety of behavioural and physiological perturbations induced by chronic stress, which has been proposed to be a better indicator of clinical stress than acute stress, and may indicate adaptogenic activity.

Animals↗