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Biomedical subjects

P Dutta

Publications and source records attributed to P Dutta.

At least 55 records · Page 3Linked to original sources
PubMed2001

Thermodynamics of interaction of water vapour with 20 different poly-L-amino acids.

The uptake of water vapour by 20 different polyaminoacids have been evaluated by an isopiestic vapour pressure technique in absence of solute at three different temperatures (22 degrees C, 30 degrees C and 37 degrees C). The water vapour adsorption isotherm for different polyaminoacids in the range of water activity varying between zero and unity apparently agreed with that expected from a type III BET isotherm. From the linear BET plots, obeyed in the lower range of water activity, the BET constants n(m) and Qm for different polyamines have been evaluated. The amount of water vapour adsorbed (n1) was calculated in moles/kg of polyaminoacids as well as in moles/mole of amino acid residue. Its value at unit water activity (deltan(o)1) has been evaluated by an extrapolation method and the results support that the multilayer adsorption of water vapour at the interface of polyaminoacids takes place. Values of deltan(o)1 are strictly comparable in terms of moles per kg rather than mole per mole unit. In case of beta lactoglobulin (betalg), lysozyme and BSA, theoretically obtained deltan(o)1 values were observed to be considerably larger than experimental values of deltan(o)1. This indicated that amino acid residues in the polypeptide release a large amount of water due to the formation of a globular structure. Using the Bull equation in the integrated form, standard free energies, deltaGo(w) for water-polyamino acid binding interaction at two different temperatures have been evaluated. Based on the Clausius-Clapeyron equation in an integrated form, the integral enthalpy for water-polyamino acid interaction has also been evaluated.

Amino Acids↗
PubMed2001

Structure of interfacial liquids: X-ray scattering studies.

We have used synchrotron x rays to study three different liquids near solid-liquid interfaces. For either ultrathin (45-90 A) or thick ( approximately 5000 A) liquid films on silicon substrates, we find (on the basis of diffraction peaks or specular reflectivity data) that the molecules form 3-6 layers at the interface, with plane spacings close to the molecular dimensions. Rough surfaces and/or impurities reduce the density oscillation amplitudes. Making the liquid film very thin does not observably enhance the effect, which implies that layering is present even at an isolated interface (i.e., in a semi-infinite liquid). On the other hand, predeposited impurities diffuse away from the interface more easily if the liquid films are thick. The liquids studied are nonconducting, nonpolar, and nonreactive; the molecules are roughly spherical; and our substrate surface has no lateral structure. Thus our observations should apply to any liquid near a hard wall.

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

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

Emergence of rotavirus G4P8 strain among children suffering from watery diarrhea in Calcutta, India.

Rotavirus RNAs from the fecal samples were hybridized with cDNAs specific for G1 and G2 genotypes. 59 out of 138 samples (42.7%) did not hybridize with either probe. The cDNAs coding for VP7 and VP4 from one such sample, SC134, were synthesized by combined reverse transcriptase/polymerase chain reaction (PCR) using specific oligonucleotide primers and were used as probes to screen those local isolates which did not hybridize with either G1 or G2. 26/59 (44%) of fecal RNA hybridized with these cDNAs indicating a possible emergence of this strain in this part of India. The VP7 and VP4 genotype specificity of SC134 was found to be G4P8 by multiplex PCR. The VP7 gene of SC134 was cloned and characterized in detail by restriction enzyme digestion and DNA sequence analysis. Comparison of nucleotide and predicted amino acid sequence of the VP7 gene of SC134 with other serotypes revealed that the VP7 gene of SC134 was closely related to G4. However, amio acids within the VP7 sequence differed in seven positions with that of both the subtype 'A' and 'B' of the G4 serotype. To establish the relation of this emerging strain with the other reported G4 strains, a phylogenetic tree was constructed and SC134 was found to be more closely related to the ST3 strain isolated in England and included in the tetravalent vaccine formulation along with two Japanese strains, although all four were distinct and did not form any cluster as was evident by the horizontal distance separating them. The VP7 gene sequence of SC134 was submitted to EMBL and was assigned the accession number AJ278217.

Antigens, Viral↗
PubMed2001

The influence of phosphodiesterase inhibitor, rolipram, on hemodynamics in lipopolysaccharide-treated rats.

Administration of bacterial endotoxin (lipopolysaccharide, LPS) intravenously has been noted to produce a shock state, which is characterized by hypotension and multi-organ system failure. The aim of the present investigation was to (a) examine the influence of rolipram on hemodynamics, plasma levels of tumor necrosis factor-alpha (TNF-alpha) levels, and production of inducible nitric oxide synthase (iNOS) in the lungs, ex vivo, in LPS-treated rats, and (b) determine the cardiovascular effects of a selective alpha1-adrenoceptor agonist, methoxamine, in the absence or presence of rolipram in rats treated with LPS. Blood pressure, cardiac index, heart rate and arterial resistance were assessed in Long-Evans rats anesthetized with thiobutabarbital. Administration of LPS to animals resulted in a significant reduction in cardiac index over time. The administration of LPS to rats resulted in a substantial rise in the plasma levels of TNF-alpha. Furthermore, the injection of LPS resulted in a significant increase in the iNOS activity in the lungs. Pre-treatment with rolipram prevented the decline in cardiac index in animals that received LPS. Infusion of methoxamine into animals injected with rolipram and pre-treated with LPS did not result in significant changes in cardiac index. Pre-treatment with rolipram or dexamethasone in animals injected with LPS significantly prevented the rise in TNF-alpha when compared to the respective values in vehicle-treated animals. Our present observations support the view that the cardiac index can be maintained in animals treated with LPS independent of iNOS inhibition.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed2001

Ceftriaxone therapy in ciprofloxacin treatment failure typhoid fever in children.

BACKGROUND & OBJECTIVES: The rapid spread of multidrug resistant (MDR) typhoid fever has posed a great challenge for the treatment of these cases the world over. After the emergence of chloramphenicol resistant Salmonella typhi strains, ciprofloxacin has become the drug of choice for the treatment of typhoid fever even in the paediatric age group. This study evaluated the role of ceftriaxone therapy in bacteriologically confirmed MDR typhoid cases who did not respond to 12-14 days of ciprofloxacin therapy. Attempts have also been made to investigate the in vitro susceptibility of isolated S. typhi strains to chloramphenicol, ciprofloxacin and ceftriaxone. METHODS: A total of 140 children, aged 3-10 yr, clinically diagnosed as having typhoid fever, without any clinical response after 12-14 days of ciprofloxacin therapy were screened for S. typhi by blood culture. In the bacteriologically positive children the treatment was changed to intravenous ceftriaxone for 14 days. The isolated strains of S. typhi were tested for in vitro antimicrobial susceptibility. RESULTS: Clinical and bacteriological cure was observed with intravenous ceftriaxone therapy in all the 32 bacteriologically positive patients. All isolated S. typhi strains were uniformly (100%) susceptible to ciprofloxacin and ceftriaxone but 50 per cent of the strains were resistant to chloramphenicol. The MIC values of chloramphenicol, ciprofloxacin and ceftriaxone ranged between 125-500, 0.0625-0.5 and < 0.0625 microgram/ml respectively. INTERPRETATION & CONCLUSION: The study indicates that although the S. typhi strains were susceptible to ciprofloxacin in vitro, the patients did not respond clinically and bacteriologically to ciprofloxacin therapy. Hence, ciprofloxacin may not represent a reliable and useful option for treating MDR typhoid fever; ceftriaxone may be an effective alternative for the treatment of such cases.

Anti-Infective Agents↗
PubMed2001

Isolation of Salmonella enterica serotypes from children with diarrhoea in Calcutta, India.

The prevalence of Salmonella enterica serotypes, antimicrobial susceptibility, and phage typing of serovers were studied. Clinical presentations of the infected cases were also examined. The study was carried out during August 1993-September 1996 in and around Calcutta, India. In total, 1,025 faecal samples from hospitalized diarrhoeal children were screened for enteropathogens. Four S. enterica serotypes were identified in 157 (15.3%) cases as a single pathogen. S. enterica serotype Typhimurium was detected in 110 (70%) cases. S. Seftenberg, S. Infantis, and S. Virchow were detected in 28 (17.8%), 14 (8.9%), and 5 (3.2%) cases respectively. S. Typhimurium was isolated from 11 (3.2%) non-diarrhoeal control children. All of these children had acute watery diarrhoea, and 5% of them had severe dehydration, 40% had some dehydration, and 55% had no dehydration. Vomiting, fever, and diffused pain in abdomen were the associated presentations of these children. Most (95%) of them recovered with oral rehydration therapy only and without any antibiotics. In-vitro susceptibility testing showed that 120 of the 121 S. Typhimurium strains isolated from cases and controls were resistant to the commonly-used drugs. Thirteen of the 121 strains were phage-typeable and belonged to the phage type 193. However, no clinical or epidemiological significance could be established with these typeable strains. The findings of the study indicate that diarrhoeagenic Salmonella is one of the major pathogens causing diarrhoeal diseases in eastern India.

Anti-Bacterial Agents↗
PubMed2001

Transmission of bancroftian filariasis in tea agro-ecosystem of Assam, India.

Tea industry is a labor intensive agro-industry and filariasis is mostly localized among the tea garden workers in Assam. The workers live inside the gardens in colonies. Studies conducted in two cosecutive years revealed that among the host seeking Culex quinquefasciatus average infection rate was 4.6% and with 2.1 larvae per mosquito. The overall prevalence of infective mosquitos was 0.8% with average L3 load of 2.0 per mosquito. The probability of infected mosquitos surviving to have complete development of filarial larvae (13 days) was 0.17. The expectation of infective life was 1.416 days for man biting Cx. quinquefasciatus and the estimated adult survival rate of was 87.6%. It has been estimated that a total of 22,569 mosquito bites were received/man/year in tea garden environment out of which 182 bites/man/year were infective (0.806%). The monthly biting rate varied from 310-4,758.5 bites per man (mean 1,846 +/- 1,389.7 SD). Monthly transmission index of W. bancrofti filaria showed two periods of transmission. In both the year no infection was detected during February and March and infection rate remained low up to May (average infection in April 0.72% and in May 0.48%).

Agricultural Workers' Diseases↗
PubMed2000

Development of a simple sperm cryopreservation model using a chemically defined medium and goat cauda epididymal spermatozoa.

This investigation was carried out to develop a simple sperm cryopreservation model using a chemically defined synthetic medium (modified Ringer's solution) and mature goat cauda epididymal sperm as the model system. Rates of cooling, freezing, and maximum freezing temperature were manipulated with the help of a computer-controlled programmable biofreezer. Highly motile goat cauda sperm dispersed in a modified Ringer's solution was subjected to the freezing protocol: cooling 0.25 degrees C min(-1) to 5 degrees C, 5 degrees C min (-1) to -20 degrees C, 20 degrees C min(-1) to -100 degrees C, prior to plunging into liquid nitrogen. In the absence of any cryoprotective agent, all of the spermatozoa lost their motility. Addition of glycerol (0.22 to 0.87 M) caused a dose-dependent increase of sperm motility recovery. The highest recovery of forward and total motility was (32 and 35%, respectively) at 0.87 M. Further increase of the glycerol concentration caused a marked decrease in motility. Changes in the cooling rate particularly before and during freezing had a notable effect on the sperm motility recovery. There was no or low recovery (0-18%) of sperm motility when the cells were transferred directly to liquid nitrogen from the initial two cooling stages. The data demonstrate the importance of all of the cooling stages in the cryopreservation of the cells. Like glycerol, dimethyl sulfoxide (Me(2)SO) and ethylene glycol also showed a dose-dependent increase in motility recovery as well as a biphasic curve of cryoprotection. At optimal concentrations, dimethyl sulfoxide (1.00 M) and ethylene glycol (1.29 M) were effective in recovering sperm motility to the extent of 20 and 13%, respectively. Thus these reagents have markedly lower cryoprotection potential than glycerol.

Animals↗
PubMed2000

Hypo-osmolar oral rehydration salts solution in dehydrating persistent diarrhoea in children: double-blind, randomized, controlled clinical trial.

UNLABELLED: A double-blind, randomized, controlled trial was conducted to compare the clinical efficacy of hypo-osmolar oral rehydration salts (ORS) solution (224 mmol/L) and standard ORS solution (311 mmol/L) in children with persistent diarrhoea who were prone to develop dehydration. Initially, 95 children aged between 3 and 24 mo were included in the study for overnight observation. Of these, 70 children who passed stool more than 2 g/kg/h were finally enrolled in the study and were randomly assigned either standard ORS or hypo-osmolar ORS. After decoding the identity of ORS, it was observed that 37 children were in the standard ORS group and 33 in the hypo-osmolar ORS group. Clinical parameters and microbiological findings of stool samples were comparable in the two groups at the time of enrolment. Total stool output (2.5+/-1.1 vs 3.2+/-1.6 kg; p = 0.04), duration of diarrhoea (114.8+/-38.3 vs 145.4+/-40.0 h; p = 0.002), total intake of ORS (5.4+/-1.6 vs 7.8+/-1.8 l; p = 0.002) and total fluid intake (7.9+/-2.6 vs 10.0+/-4.1 l, p = 0.01) were significantly less in the hypo-osmolar ORS group compared to the standard ORS group. However, the percentage of weight gain on recovery in the hypo-osmolar group was less compared to that of the standard ORS group, though the difference was statistically insignificant. Thirty-five (95%) children in the standard ORS and 33 (100%) children in the hypo-osmolar group recovered within 10 d of initiation of therapy and modified dietary management. CONCLUSION: Our findings suggest that hypo-osmolar ORS has beneficial effects on the clinical course of dehydrating persistent diarrhoea.

Body Weight↗
PubMed2000

Soy sterol esters and beta-sitostanol ester as inhibitors of cholesterol absorption in human small bowel.

BACKGROUND: Plant sterols are natural dietary components with serum cholesterol-lowering properties. The lowering of serum cholesterol by plant sterols is believed to be the result of an inhibition of cholesterol absorption in the small bowel, although increased bile acid excretion has also been suggested. The difference in effect of saturated and unsaturated plant sterols on cholesterol absorption needs to be elucidated further. OBJECTIVE: The primary aim of this study was to measure small-bowel cholesterol absorption and sterol excretion in addition to hepatic cholesterol synthesis after intake of soy sterol esters and beta-sitostanol ester corresponding to 1.5 g plant sterols/d. DESIGN: Seven ileostomy subjects were studied during a control period and 2 intervention periods when either soy sterol esters or beta-sitostanol ester was added to a basal diet. Ileostomy bags were collected every other hour and frozen immediately for analysis of nutrients and sterols. RESULTS: Cholesterol absorption was 56% (43-65%) in the control period and decreased to 38% (32-46%) in the soy sterol ester period (P = 0.00) and to 39% (30-48%) in the beta-sitostanol ester period (P = 0.00). CONCLUSION: Esterified soy sterols and beta-sitostanol inhibited cholesterol absorption equally, despite the different structures of the plant sterols.

Adult↗
PubMed2000

Impact of zinc supplementation in malnourished children with acute watery diarrhoea.

A double-blind, randomized, controlled clinical trial was conducted on 80 malnourished children with acute dehydrating diarrhoea to evaluate the efficacy of oral supplementation of zinc as an adjunct therapy to oral rehydration solution (ORS). After decoding it was observed that 44 children received zinc sulphate (177 mg/kg/day in three divided doses equivalent to 40 mg elemental zinc) in a syrup form and 36 children received only syrup placebo. Clinical parameters and microbiological findings of stool samples were comparable in the two groups at the time of enrollment. All the children (100 per cent) in the zinc supplemented group and 32 (89 per cent) children in the placebo group recovered within 5 days of hospitalization (p = 0.04). The zinc supplemented group had a significantly shorter duration of diarrhoea (70.4 +/- 10.0 vs. 103.4 +/- 17.1 h; p = 0.0001), passed less liquid stool (1.5 +/- 0.7 vs. 2.4 +/- 0.7kg; p=0.0001), consumed less oral rehydration solution (2.5 +/- 1.0 vs. 3.6 +/- 0.8 litre; p = 0.0001) and other liquids (867.0 +/- 466.1 vs. 1354.7 +/- 675.6 ml; p = 0.0001) as compared to the placebo group. Our findings suggest that zinc supplementation as an adjunct therapy to ORS has beneficial effects on the clinical course of dehydrating acute diarrhoea.

Acute Disease↗
PubMed2000

In situ and interrupted-growth studies of the self-assembly of octadecyltrichlorosilane monolayers

We have examined the self-assembly process of octadecyltrichlorosilane on silicon using x-ray reflectivity. By comparing the commonly used "interrupted-growth" characterization technique with results obtained in situ, we have determined that quenching the growth and then rinsing and drying the sample introduces free area into the film, presumably by removal of non-cross-linked (physisorbed) molecules. Reintroduction of a quenched and rinsed film to solvent does not restore the thickness of the film to its previous value. We have also performed in situ growth studies over a range of concentrations. For all concentrations, we observe growth of islands of vertical molecules. The growth follows Langmuir kinetics, except at short times for low concentration solutions.

Journal Article↗
PubMed2000

Enteroaggregative Klebsiella pneumoniae in association with childhood diarrhoea.

A total of 19 strains of Klebsiella pneumoniae isolated as sole pathogen from children with diarrhoea were used to study their virulence mechanism using different assays. Eith strains of K. pneumoniae exhibited aggregative adherence that was distinct from the stacked brick enteroaggregative pattern shown by Escherichia coli. The study suggests the presence of a new virulence mechanism in the pathogenesis of Klebsiella-associated diarrhoea.

Child, Preschool↗