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Biomedical subjects

B Sengupta

Publications and source records attributed to B Sengupta.

At least 19 recordsLinked to original sources
PubMed2004

Source apportionment of ambient VOCs in Delhi City.

Source apportionment using chemical mass balance (CMB) model was carried using a data set of 360 four hourly samples collected at 15 locations of five categories namely residential, commercial, industrial, traffic intersections and petrol pumps during August 2001-July 2002 in Delhi. The results indicate that emissions from diesel internal combustion engines dominate in Delhi. Vehicular exhaust and evaporative emissions also contribute significantly to VOCs in ambient air. Emission of VOCs associated with sewage sludge was also found to contribute to VOCs in Delhi's air. This points to the fact that open defecation and leaking sewage manholes are a problem in all categories of locations.

Air Pollutants↗
PubMed2003

Single megadose vitamin A supplementation of Indian mothers and morbidity in breastfed young infants.

BACKGROUND AND OBJECTIVE: In developing countries low maternal vitamin A stores combined with increased demands of pregnancy and lactation may lead to its deficiency in breastfed infants. This study evaluates the effects of maternal supplementation with a high dose of vitamin A on the serum retinol levels of exclusively breastfed infants, and their morbidity in the first six months of life. SETTING: Hospital based. STUDY DESIGN: Randomised controlled trial. SUBJECTS AND METHODS: Mothers of the test group (n=150) were orally supplemented with a single dose of retinol (209 micro mol) soon after delivery and were advised exclusive breastfeeding for six months. Before supplementation retinol levels were estimated in the mothers' and newborns' blood, and in colostrum. On follow up, breastmilk and infants' serum retinol contents were assessed monthly for six months. Retinol level <0.7 micro mol/l indicated vitamin A deficiency. Morbidity patterns like vitamin A deficiency, diarrhoea, febrile illnesses, acute respiratory infection, measles, and ear infection were also studied and compared between the two groups. RESULTS: Presupplement mean maternal serum retinol levels were 0.98 and 0.92 micro mol/l and mean breastmilk levels were 3.85 and 3.92 micro mol/l in the test and control groups respectively (p>0.05). Mean cord blood retinol levels were also comparable (0.68 v 0.64 micro mol/l). After supplementation, the test group showed a rise in mean breastmilk retinol content (12.08 v 2.96 micro mol/l) which remained significantly higher for four months. The infants' mean serum retinol level, initially 322.06% of the baseline value, was significantly higher for five months. In the control group, significant numbers of mothers and infants showed deficient breastmilk and serum retinol throughout the follow up (p<0.01). Decreased incidence and duration of various diseases were also found in the test group suggesting lesser morbidity. CONCLUSION: Maternal supplementation with single megadose vitamin A is an effective strategy for vitamin A prophylaxis of exclusively breastfed infants of 0-6 months.

Administration, Oral↗
PubMed2001

Protein-flavonol interaction: fluorescence spectroscopic study.

Recent studies have shown that various synthetic as well as therapeutically active naturally occurring flavonols possess novel luminescence properties that can potentially serve as highly sensitive monitors of their microenvironments in biologically relevant systems. We report a study on the interactions of bovine serum albumin (BSA) with the model flavonol 3-hydroxyflavone (3HF), using the excited-state proton-transfer (ESPT) luminescence of 3HF as a probe. Upon addition of BSA to the flavonoid solutions, we observe remarkable changes in the absorption, ESPT fluorescence emission and excitation profiles as well as anisotropy (r) values. Complexation of 3HF with protein results in a pronounced shift (20 nm) of the ESPT emission maximum of the probe (from lambda(max)(em) = 513 nm to lambda(max)(em) = 533 nm) accompanied by a significant increase in fluorescence intensity. The spectral data also suggest that, in addition to ESPT, the protein environment induces proton abstraction from 3HF leading to formation of anionic species in the ground state. Fairly high values of anisotropy are observed in the presence of BSA for the tautomer (r = 0.25) as well as anion (r = 0.35) species of 3HF, implying that both the species are located in motion-restricted environments of BSA molecules. Analysis of relevant spectroscopic data leads to the conclusions that two binding sites are involved in BSA-3HF interaction, and the interaction is slightly positively cooperative in nature with a similar binding constant of 1.1 - 1.3 x 10(5) M(-1) for both these sites. Proteins 2001;43:75-81.

Anisotropy↗
PubMed2000

Influence of reverse micellar environments on the fluorescence emission properties of tryptophan octyl ester.

A number of recent studies have presented perspectives on the hydrophobic fluorescence probe tryptophan octyl ester (TOE). This molecule has attracted notable attention as a suitable model for the natural fluorophore tryptophan, in case of membrane proteins. We report here, for the first time, the fluorescence emission behaviour of TOE in reverse micelles of aerosol-OT (AOT) in n-heptane, containing different amounts of water. Relevant studies in representative homogeneous solvent media are also included for comparison. The fluorescence emission parameters (especially emission maximum, relative intensity, and anisotropy) of TOE are found to exhibit significant variation upon changes in the water/surfactant molar ratio (w(0)) of the reverse micelles. Fluorescence decay studies on TOE which we have also performed, indicate biexponential decay kinetics in reverse micelles as well as in homogeneous solvent media. The implications of these findings are examined in relation to the potentialities of TOE as a novel fluorescence probe for membrane proteins present in water restricted environments prevailing at the interfaces of biomembranes (for which reverse micelles serve as ideal model systems).

Acetates↗
PubMed2000

Characterization of the fluorescence emission properties of prodan in different reverse micellar environments.

We have examined the steady state and time resolved fluorescence emission properties of the hydrophobic fluorescence probe, prodan, in three representative reverse micellar systems formed by the surfactants poly(oxyethylene) (tetramethylbutyl) phenylether (Triton X-100, neutral), cetyl trimethylammonium bromide (CTAB, cationic) and sodium bis-(2-ethylhexyl) sulfosuccinate (AOT, anionic) in organic solvent media containing different concentrations of water. The results obtained from the experiments indicate conspicuous dependence of the emission behaviour of prodan on the type of surfactant used and the water/surfactant molar ratio (w0). The nature of the emission profiles, along with relevant parameters namely emission maximum (lambda(em)max), anisotropy (r) and lifetime (tau) data are used to infer the distribution and microenvironments of the prodan molecules in the reverse micelles at different w0 values. Furthermore, quantitative estimates have been obtained for the polarities (in terms of the empirical polarity parameter E(T)(30)) of the sites of solubilization of the fluorophore in different reverse micellar systems.

2-Naphthylamine↗
PubMed2000

Luminescence behaviour of 5-hydroxyindole in different environments.

Steady state fluorescence emission spectroscopic studies along with some lifetime measurements have been performed for 5-hydroxyindole (5HI) in different environments. 5HI merits particular attention, since it is the chromophoric moiety of the non-natural amino acid 5-hydroxytryptophan (5HT), which has come into significant, recent prominence as a novel intrinsic optical probe for protein structure, function and dynamics. Studies in representative homogeneous solvents and solvent-mixtures indicate that unlike other fluorophores of related interest like indole (I) and 7-azaindole (7AI), the fluorescence emission maximum (lambda(em)max) of 5HI is relatively insensitive to solvent polarity. This behaviour suggests the lack of appreciable solvent dipolar relaxation in 5HI, which is consistent with our low temperature (77 K) emission data. Notwithstanding such limitation, fluorescence anisotropy (r) and quenching studies are shown to be effective for exploring changes in the micro-environments of 5HI in sodium bis-(2-ethylhexyl)sulfosuccinate (AOT) reverse micellar assemblies (which serve as a biomembrane mimetic model system) with variation in water/surfactant molar ratio (w0).

Fluorescence Polarization↗
PubMed1998

Perception and practice regarding pulse polio immunisation in an urban community of Calcutta.

A survey was conducted at an Integrated Child Development Services (ICDS) Scheme project in North Calcutta among 656 mothers having children less than 3 years of age to assess their perception and practice regarding pulse polio immunisation (PPI). It was revealed that 91.8% of under 3-year children received PPI on 9-12-1995 and 94.4% on 20-1-1996. Major reasons for not accepting the services on those two days included 'mothers unaware' (22%), 'child too small' (30.5%), etc. Major source of first information was television (TV)/radio (57.2%) followed by anganwadi workers (AWWs) (33.8%). However, majority of the mothers were finally motivated for PPI by AWWs (58.8%) followed by the role of TV/radio (34.1%). Although 70.7% mothers knew the name of the vaccine correctly, only 3.5% mothers could tell the exact purpose of its administration. Most mothers (73%) opined that 2 drops of oral polio vaccine (OPV) was administered to their children and only 14.6% hoped that such programmes will be conducted by the Government in future. The average waiting time of mothers at immunisation centres was found to be 7.2 minutes.

Age Factors↗
PubMed1998

Experience in running a Diarrhoeal Training cum Treatment Unit (DTTU) in a state teaching hospital in Calcutta.

The performance of the Diarrhoeal Training cum Treatment Unit (DTTU) of NRS Medical College and Hospital, Calcutta, in a 2-year period was evaluated by record analysis. The study revealed that 73.6% cases out of a total 4349 could be successfully managed at the oral rehydration therapy (ORT) area and only 16.5% cases required indoor admission. Rest of the cases (9.9%) with "no dehydration" were sent home with advice. There were 84.7% cases out 3919 dehydration cases who could be successfully treated by ORT and only 15.3% required intravenous (i.v.) therapy. A definite decline was also evident in the proportion of diarrhoea cases requiring antibiotic therapy (13.5% in 1991 to 6.8% in 1992). The case fatality rate due to diarrhoea was 1.7% in 1992. Had all cases of diarrhoea with dehydration being admitted and treated with i.v. fluids and antibiotics, the estimated cost would have been Rs 14.2 lakhs, which with ORT, actually cost Rs 2.4 lakhs. Thus estimated total cost reduction was to the extent of Rs 11.8 lakhs in a 2-year period.

Anti-Bacterial Agents↗
PubMed1994

Human immunodeficiency virus infection related to blood transfusion service.

The prevalence of transmissible viruses, human immunodeficiency (HIV) and hepatitis B (HBV) in blood donors, recipients and blood bank staff in a Calcutta (eastern India) based blood bank and transfusion centre has been studied from 1987-93. HIV seropositivity of blood donors was of recent emergence and was low. Recipients of blood and blood components frequently i.e., haemophilics showed a progressive increase in HIV seropositivity since 1988 whereas in thalassaemics the emergence of HIV seropositivity was noted only in 1992. Blood bank staff were seronegative. HBV which has a similar portal of entry as HIV, had a higher prevalence in blood donors, recipients of blood/components and blood bank staff.

Blood Banks↗
PubMed1993

Immunosurveillance of transfusion dependent thalassaemia and hepatitis B vaccination.

The study evaluates the probable alteration of the immune system in multitransfused thalassaemics and the modification of their immune response following administration of hepatitis B virus (HBV) vaccine. B-thalassaemics (n = 50) and EB-thalassaemics (n = 30) who received multiple blood transfusion for the chronic anaemic status had significant iron overload. They had high prevalence for hepatitis B carrier state and almost all were exposed to hepatitis B virus during the course of transfusion as shown by the positivity of hepatitis B virus markers. Thalassaemics in presence of iron overload have altered immune status in terms of depressed T-lymphocytes and raised immunoglobulins G and M. However, they showed 100 per cent seroconversion with production of antibody to hepatitis B surface antigen following Hepatitis B vaccination.

Adolescent↗
PubMed1993

Hepatitis B vaccination and the rate of seroconversion in high risk contacts.

Twenty-seven employees of a blood transfusion centre, Calcutta were vaccinated with hepatitis B vaccine (recombinant DNA technology), 20 micrograms/1 ml intramuscularly on 0, 8, 32 weeks interval. The seroconversion rate at 8, 32, 40 weeks were 29.6%, 55.5% and 100% respectively. The recombinant hepatitis B vaccine is acceptable and safe. The seroconversion rate is comparable to plasma derived hepatitis B vaccine.

Blood Banks↗
PubMed1992

Sero-surveillance of transmissible hepatitis B & C viruses in asymptomatic HIV infection in haemophilics.

In a group of 37 haemophilics, 9 (24.3%) were seropositive for human immunodeficiency virus (HIV), while 9 (24.3%) and 10 (27%) were positive for hepatitis B virus (HBV) and hepatitis C virus (HCV) respectively. Haemophilics who were HIV seropositive had higher prevalence of HBV and HCV. Seropositivity for HIV was more in patients with severe haemophilia A who required frequent factor VIII replacement. The need for long term surveillance of voluntary blood donors for transfusion associated viruses like HIV, HBV and HCV, is emphasized.

Adolescent↗