Biomedical subjects

D Bhattacharyya

Publications and source records attributed to D Bhattacharyya.

At least 19 recordsLinked to original sources

PubMed2006

Modified Fenton reaction for trichlorophenol dechlorination by enzymatically generated H2O2 and gluconic acid chelate.

Glucose oxidase is a well-known enzyme that catalyzes the oxidation of beta-D-glucose to produce gluconic acid and hydrogen peroxide. Fenton reaction is a powerful oxidation technology used for the oxidation of groundwater pollutants. For the application of Fenton reaction in groundwater remediation, successful operation of Fenton reaction near neutral pH, and on-site generation of both H2O2 and chelate will be beneficial. The focus of this experimental study was to couple the glucose oxidation reaction with chelate-based Fenton reaction. The idea was to use the hydrogen peroxide and chelate gluconic acid generated during glucose oxidation for the dechlorination of 2,4,6-trichlorophenol (TCP) by Fenton reaction. The oxidation of glucose was achieved using the enzyme in free and immobilized forms. The rate of production of hydrogen peroxide was determined for each system, and was used to estimate the time required for complete consumption of glucose during the process, thus avoiding any traces of glucose in the Fenton reaction. In the case of free enzyme reaction, separation of the enzyme was achieved using an ultrafiltration membrane before initiating the Fenton reaction. The oxidation of TCP by Fenton reaction was performed at varying ratios of gluconic acid/Fe, and its effect on the decomposition of TCP and H2O2 was studied. TCP degradation was studied both in terms of parent compound degradation and free chloride generation.

Chelating Agents↗

PubMed2006

Layer-by-layer-assembled microfiltration membranes for biomolecule immobilization and enzymatic catalysis.

Multilayer assemblies of polyelectrolytes, for protein immobilization, have been created within the membrane pore domain. This approach was taken for two reasons: (1) the high internal membrane area can potentially increase the amount of immobilized protein, and (2) the use of convective flow allows uniform assembly of layers and eliminates diffusional limitations after immobilization. To build a stable assembly, the first polyelectrolyte layer was covalently attached to the membrane surface and inside the pore walls. Either poly(L-glutamic acid) (PLGA) or poly(L-lysine) (PLL) was used in this step. Subsequent deposition occurs by multiple electrostatic interactions between the adsorbing polyelectrolyte [poly(allylamine) hydrochloride (PAH) or poly(styrenesulfonate) (PSS)] and the oppositely charged layer. Three-layer membranes were created: PLL-PSS-PAH or PLGA-PAH-PSS, for an overall positive or negative charge, respectively. The overall charge on both the protein and membrane plays a substantial role in immobilization. When the protein and the membrane are oppositely charged, the amount immobilized and the stability within the polyelectrolyte assembly are significantly higher than for the case when both have similar charges. After protein incorporation in the multilayer assembly, the active site accessibility was comparable to that obtained in the homogeneous phase. This was tested by affinity interaction (avidin-biotin) and by carrying out two reactions (catalyzed by glucose oxidase and alkaline phosphatase). Besides simplicity and versatility, the ease of enzyme regeneration constitutes an additional benefit of this approach.

Adsorption↗

PubMed2006

Estimation of strength in different extra Watson-Crick hydrogen bonds in DNA double helices through quantum chemical studies.

It was shown earlier, from database analysis, model building studies, and molecular dynamics simulations that formation of cross-strand bifurcated or Extra Watson-Crick hydrogen (EWC) bonds between successive base pairs may lead to extra rigidity to DNA double helices of certain sequences. The strengths of these hydrogen bonds are debatable, however, as they do not have standard linear geometry criterion. We have therefore carried out detailed ab initio quantum chemical studies using RHF/6-31G(2d,2p) and B3LYP/6-31G(2p,2d) basis sets to determine strengths of several bent hydrogen bonds with different donor and acceptors. Interaction energy calculations, corrected for the basis set superposition errors, suggest that N-H...O type bent EWC hydrogen bonds are possible along same strands or across the strands between successive base pairs, leading to significant stability (ca. 4-9 kcal/mol). The N-H...N and C-H...O type interactions, however, are not so stabilizing. Hence, consideration of EWC N-H...O H-bonds can lead to a better understanding of DNA sequence directed structural features.

Base Pairing↗

PubMed2006

Ethoxylated nonionic surfactants in hydrophobic solvent: interaction with aqueous and membrane-immobilized poly(acrylic acid).

Interaction between ethoxylated nonionic surfactants and poly(acrylic acid) (PAA) in aqueous solutions is well-documented in the literature. In the present study, pure ethoxylated surfactant solution in a hydrophobic solvent was permeated through a partially cross-linked PAA composite membrane to quantify the surfactant-PAA interaction in the heterogeneous system. Partitioning of the mixture of the surfactants (15-S-5) between the hydrophobic solvent and aqueous solution of PAA was also studied. The role of ethylene oxide group variation in the surfactant-PAA interaction for the heterogeneous system was established by performing experiments with pure surfactants having the same alkyl chain length but varying ethoxylate chain lengths. It was observed that the surfactants with a higher number of ethylene oxide groups per molecule exhibit stronger interaction with PAA. The literature data for adsorption of pure ethoxylated surfactants (C12E(n)) on a hydrophobic solid-water interface was correlated and compared with the data obtained in our study. It was calculated that resistance in terms of transfer of surfactant molecules from a hydrophobic solvent domain to PAA domain lowers the extent of PAA-surfactant interaction by an order of magnitude. Only 40% of available carboxyl groups were accessible for interaction with the ethoxylated nonionic surfactants due to diffusion limitations. Finally the pH sensitivity of the PAA-surfactant complex was verified by successful regeneration of the membrane on permeation of slightly alkaline water. The regeneration and reuse of membrane is especially attractive in terms of process development for nonionic surfactant separation from hydrophobic solvents.

Journal Article↗

PubMed2006

Dietary comparison of conjugated linolenic acid (9 cis, 11 trans, 13 trans) and alpha-tocopherol effects on blood lipids and lipid peroxidation in alloxan-induced diabetes mellitus in rats.

The present study investigated the dietary effect of conjugated linolenic acid (CLnA) on lipid profiles and lipid peroxidations in alloxan-induced diabetes mellitus in rats. Diabetic rats were fed with 20% sunflower oil (diabetic control), sunflower oil supplemented with 0.5% CLnA, sunflower oil supplemented with 0.15% alpha-tocopherol, and sunflower oil containing 0.25% CLnA + 0.15% alpha-tocopherol. The results demonstrated that 0.5% CLnA, 0.15% alpha-tocopherol, and 0.25% CLnA + 0.15% alpha-tocopherol each on supplementation significantly lowered total cholesterol and non-HDL-cholesterol in comparison with the diabetic control group. The TAG level was significantly lowered in both the 0.15% alpha-tocopherol and 0.25% CLnA + 0.15% alpha-tocopherol groups. LDL-lipid peroxidation and erythrocyte membrane lipid peroxidation were reduced significantly in each of the experimental groups vs. the control group. The CLnA + alpha-tocopherol diet induced a greater reduction in membrane lipid and liver lipid peroxidation than the alpha-tocopherol diet alone. In conclusion, dietary CLnA exerts antioxidant activity as evidenced by reduced lipid peroxidation in chemically induced diabetes mellitus.

Alloxan↗

PubMed2006

Neuropharmacological effects of deltamethrin in rats.

This study examined the effect of deltamethrin on some of the neuropharmacological paradigms in a rat brain such as the motor co-ordination test using a rotarod, the pentobarbitone-induced sleeping time and pentylenetetrazole (PTZ)-induced convulsion as well as the gamma aminobutyric acid (GABA) level. Albino Wistar rats were used as the experimental animals. Different neuropharmacological paradigms such as the motor co-ordination by the rotarod, pentobarbitone-induced sleeping time and the PTZinduced convulsion were examined after administering deltamethrin orally at two doses, 150 mg/kg (LD50) and 15 mg/kg (1/10 LD50). The GABA level in the rat brain was estimated by HPLC after a single oral dose of 150 mg/kg deltamethrin. Deltamethrin significantly reduced the motor coordination, decreased the onset time and increased the sleeping time duration induced by pentobarbitone. In addition, it also decreased the onset time and increased the duration of convulsions induced by PTZ at 150 mg/kg (LD50) and 15 mg/kg (1/10 LD50), respectively. Further deltamethrin administration decreased the GABA levels in the cerebellum as well as in the whole brain (except the cerebellum) significantly at the LD50 dose level. There was some correlation between the effect of deltamethrin on the central GABA levels and its neuropharmacological effects.

Animals↗

PubMed2005

Prevention of HIV-1 infection by platinum triazines.

To identify and explore the activity of compounds which may act as anti-HIV virucidal agents, we have investigated platinum compounds, especially those containing N-donor aromatic ligands. After screening over 70 related agents, including N-donor aromatic ligands and metal precursors, we have identified a novel class of platinum(II) complexes with 2-pyridyl-1,2,4-triazine derivatives and Pt(II) formulations with these derivatives (ptt compounds) as having the highest anti-HIV activity. The maximum activity was observed when the agents were added immediately post-infection. The ptt agents did not block cell fusion activity of HIV-1 Env proteins in cells bearing CD4X4 or CD4R5 receptors, indicating a lack of interaction with the Env protein. The ptt compounds exhibit low toxicity for human epithelial cells, and are thus promising candidates for use as microbicides or antiviral agents against HIV.

Animals↗

PubMed2005

Isolation, phage typing and antibiogram of Salmonella from man and animals in northeastern India.

BACKGROUND AND OBJECTIVE: Salmonella is an important zoonotic pathogen and its prevalence in the animals acts as a continuous threat to man. The present study was carried out to report the isolation along with the serotypes, phage types and antibiogram pattern of Salmonella among man, livestock and poultry in the northeastern India. METHODS: A total of 654 samples from diarrhoeic livestock and humans were processed for the isolation of Salmonella. All the isolates were subjected to antibiogram studies against 15 antimicrobials. Representative isolates of S. Typhimurium and S. Enteritidis were phage typed. RESULTS: Ninety five isolates of Salmonella enterica belonging to 5 serotypes- S. Typhimurium, S. Enteritidis, S. Gallinarum, S. Paratyphi B and S. Bareilly were obtained with an overall prevalence rate of 14.40 per cent. S. Typhimurium isolates were distributed among four phages- DT003, DT004, DT096 and DT193 and all the S. Enteritidis isolates belonged to a single phage type, PT13a/7. Interspecies sharing of the phages was observed. Norfloxacin, enrofloxacin, gentamycin and ciprofloxacin were most effective, whereas, doxycycline, ampicillin, amoxycillin and tetracycline were relatively less effective. INTERPRETATION AND CONCLUSION: Our findings showed that three of the five serovars as well as some of the phage types of these serovars were shared by animals and humans indicating the zoonotic potential of the organism. Thus, it is imperative that salmonellosis control measures adopted for humans should give adequate importance to its control in the animals particularly their products.

Animals↗

PubMed2004

Pore assembled multilayers of charged polypeptides in microporous membranes for ion separation.

In this study, highly permeable ion-selective membranes are prepared via immobilization of polyelectrolyte multilayer networks within the inner pore structure of a microporous (pore size = 0.2 microm) support. Electrostatic layer-by-layer assembly is achieved through alternate adsorption of cationic and anionic polyelectrolytes under convective flow conditions. To initiate pore assembly, the first layer consists of covalently bound charged polypeptides (poly(L-glutamic acid) (PLGA) or poly(L-lysine) (PLL)) establishing a charged support for subsequent adsorption. Nonstoichiometric immobilization of charged multilayers within a confined pore geometry leads to an enhanced volume density of ionizable groups in the membrane phase. This overall increase in the effective charge density allows for Donnan exclusion of ionic species (especially divalent co-ions) using microporous materials characterized by permeability values that exceed conventional membrane processes. Multilayer assemblies are fabricated using both PLGA/PLL and synthetic polyelectrolytes (poly(styrenesulfonate)/poly(allylamine)) in an attempt to compare the level of adsorption and separation properties of the resulting materials. The role of salt concentration in the carrier solvent on overall polyelectrolyte adsorption was examined to determine its effect on both solute (Cl-, SO4(2-), As(V)) and water transport. Constriction of the pore size induced by multilayer propagation was monitored through permeability measurements and dextran rejection studies at each stage of the deposition process.

Adsorption↗

PubMed2004

Comparative study of different surface decontaminants on chicken quality.

(1) A comparative study on the effect of different surface decontaminants: hot water at 70 degrees C for one minute; 2% lactic acid for 30 s; 1200 p.p.m. acidified sodium chlorite (ASC) solution for 5 s and 50 p.p.m. chlorine solution for 5 min in the form of dips and sprays on the surface of dressed broilers for 0, 24 and 48 h of storage was conducted. (2) The variables studied were, total plate count (TPC), presumptive coliform count (PCC), pH and extract release volume (ERV). All treatments reduced TPC and PCC. (3) Lactic acid dip and hot water dip were the most effective for reducing TPC (1.36 and 1.28 log/cm2, respectively) with no significant difference between them. (4) ASC and hot water in dip could diminish PCC (1.37 and 1.34 log/cm2, respectively) and did not vary significantly. (5) No treatment affected muscle pH, water holding capacity (WHC), ERV, appearance, smell, tenderness and overall acceptability of treated broilers significantly. (6) Hot water treatment is the cheapest, most convenient and simplest decontamination technique for hygienic and wholesome poultry production.

Animals↗

PubMed2004

Repeated dose toxicity of alfa-cypermethrin in rats.

The present study was performed to investigate the subacute effect of alpha-cypermethrin (alpha-CP) in rats. Alfacypermethrin a synthetic pyrethroid insecticide, dissolved in dimethyl sulfoxide (DMSO) and oral LD50 was investigated after administering orally different doses in rats and was determined as 145 mg/kg. Other groups of rats were given repeated daily oral dose (1/10 LD50) of alpha-CP for 30 days. The animals were sacrificed on 31st day. Activities of various enzymes, cytochrome P450 and b5 contents in liver, hepatic antioxidant status, tissue residue concentration, haemogram and pathological changes were studied. It increased the serum aminotransaminases (AST, ALT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH) activities and blood glucose level significantly. alpha-CP decreased RBC count, PCV and Hb level significantly. It significantly decreased cytochrome P450 in liver. Residues were present in different tissues. It increased malondialdehyde (MDA) level, while decreased the activities of catalase (CAT), superoxide dismutase (SOD) and glycogen level in liver significantly. Mild to moderate histological alterations were observed in lungs, liver, stomach, kidneys, testes and cerebellum. So repeated daily oral doses of alpha-CP at 1/10LD50 altered the biochemical parameters, decreased cytochrome P450 content, antioxidant status, which correlated with histopathological changes of tissues.

Alanine Transaminase↗

PubMed2003

Stage-dependent hatching responses of rohu (Labeo rohita) embryos to different concentrations of cryoprotectants and temperatures.

Hatching performances of three embryonic stages of postfertilization rohu (Labeo rohita) (9-, 12-, and 15-h) were examined after treatment with various concentrations (0.5-4.5M) of two cryoprotectants (methanol and propylene glycol) supplemented with 0.1M trehalose. Different lengths of storage (1-48 h) and temperature (-4 degrees C to ambient) were studied. Of the three stages of embryonic development, the 12-h stage proved to be the most suitable stage for low temperature storage, showing the highest percentage of hatch out (72+/-2%) with 2.0M methanol and 0.1M trehalose. Methanol was more useful for storage at higher temperatures and propylene glycol at subzero temperatures. The maximum possible duration of effective storage of 12-h embryos was 31h in 2.0M methanol at 0 degrees C. No hatch out was found beyond 31h of storage with all concentrations of methanol at 0 degrees C. The results of interactions was that the optimal concentration of methanol was 3.0M at 4 degrees C, 2.0M at 0 degrees C, and 1.5M at 4 degrees C. Among three embryonic stages 12-h stage showed better results in trehalose treatment than sucrose. Among all concentrations of trehalose tested 0.1M gave the maximal survival rate of the rohu embryos.

Animals↗

PubMed2003

Hatching of common carp (Cyprinus carpio L.) embryos stored at 4 and -2 degrees C in different concentrations of methanol and sucrose.

The hatching performance of common carp (Cyprinus carpio L.) embryos was examined after 12-72-h storage at 4 and -2 degrees C using different concentrations of sucrose (0.1, 0.25, 0.5 and 1.0 M or 3.42, 8.55, 17.10 and 34.2%), methanol (MeOH) (0.5, 1.0, 1.5, 2.0, 2.5, 3.0 and 3.5 M or 1.6, 3.2, 4.8, 6.4, 8.0, 9.6 and 11.2%), or varying concentrations of methanol in 0.5 M (17.10%) sucrose. For sucrose, 0.5 M (17.10%) showed the maximum survival (41+/-1% (12 h) to 11+/-1.5% (72 h)) at 4 degrees C. No survival was observed at -2 degrees C with any concentration of sucrose. At both temperatures employed, hatching was higher with mixed combination of methanol (1.5 M or 4.8%) and 0.5 M (17.10%) sucrose (4 degrees C: 41+/-1.5% (12 h), 38+/-1.2% (72 h); -2 degrees C: 33+/-1.7% (12 h), 28+/-1.2% (72 h)) compared to methanol alone (4 degrees C: 38+/-1.5% (12 h), 35+/-2.5% (72 h); -2 degrees C: 31+/-2.5% (12 h), 25+/-2% (72 h)). The combination of 1.5 M (4.8%) methanol and 0.5 M (17.10%) sucrose produced the best results among all the concentrations tested at both temperatures.

Animals↗

PubMed2003

Prenatal exposure to high galactose adversely affects initial gonadal pool of germ cells in rats.

BACKGROUND: In rats, prenatal exposure to high concentrations of galactose may contribute to a condition that is equivalent to the premature ovarian failure (POF) component of human galactosaemia. We investigated if development of POF under experimental galactosaemia-like conditions was attributed to impaired germ cell migration. METHODS: Pregnant rats were fed pellets supplemented with, or without, 35% galactose from day 3 of conception continuing through parturition. Between days 12-15, embryos from one uterine horn were dissected out. Primordial germ cells (PGC) were histochemically localized and counted on the basis of binding of Dolichos biflorus agglutinin, a lectin specific for terminal N-acetylgalactosamine (GalNAc), to the surface glycoconjugate of the germ cells. The embryos from the other uterine horn were maintained until parturition. Liver activity of uridine diphosphate galactose 4-epimerase, the enzyme involved at multiple steps in the process of synthesis of GalNAc, was assayed in 1-2 day old female pups. RESULTS: The numbers of PGC at the day-specific sites on all days of examination were significantly lower (P </= 0.0003), and liver epimerase activity was significantly (P = 0.000001) reduced in the galactose-exposed group. CONCLUSION: Impaired germ cell migration leading to the development of gonads with deficient initial pools of germ cells may form the causal link between galactosaemia and POF.

Animals↗

PubMed2003

Advances in solvent-resistant nanofiltration membranes: experimental observations and applications.

Nanofiltration (NF) and reverse osmosis (RO) are well-established membrane technologies for applications involving aqueous streams. The principles of NF transport (diffusion, convection, and Donnan exclusion) are effectively used to develop novel membrane materials and applications in aqueous medium. Use of NF in a non-aqueous medium holds strong potential for the food, refining, and pharmaceutical industries because of the low energy costs involved with such membrane processes. Further understanding and development of solvent-resistant NF membranes provides opportunities for various hybrid processing ranging from reactor-membrane to distillation-membrane combinations. This paper provides a comprehensive overview of literature results and our own work in the area of non-aqueous systems. For solvent-based systems, potential membrane swelling and solvent-solute coupling needs to be considered for membrane design and transport theories. A simplified transport theory for pure solvents has been developed using solvent (molar volume, viscosity) and membrane properties (membrane surface energy). This model and has been verified with literature data for both hydrophilic and hydrophobic membranes. Membrane characterization and preconditioning aspects need to be given serious consideration for evaluating membrane performance. In addition to permeability and separation results, some novel applications of NF in non-aqueous solvents are included in this paper.

Biotechnology↗

PubMed2003

Hepatoprotective effect of Himoliv, a polyherbal formulation in rats.

The effect of Himoliv (HV) was evaluated in carbon tetrachloride or paracetamol induced hepatotoxicity in rats. Liver necrosis was produced by administering single dose of either carbon tetrachloride (CCl4, 1 ml/kg, 50% v/v with olive oil, s.c.) or paracetamol (PC, 1 g/kg, p.o.). The liver damage was evidenced by elevated levels of serum glutamate oxaloacetate transaminase (SGOT), serum glutamate pyruvate transaminase (SGPT) and serum alkaline phosphatase (ALP) and hepatic thiobarbituric acid reacting substances (TBARS) and superoxide dismutase (SOD). HV pretreatment (0.5 and 1.0 ml/kg, p.o.) significantly (P < 0.001) reduced CCl4 or PC-induced elevations of the levels of SGOT, SGPT, ALP and TBARS, while the reduced concentration of SOD due to CCl4 or PC was reversed. Silymarin (25 mg/ kg, p.o.), a known hepatoprotective drug showed similar results.

Acetaminophen↗

PubMed2002

Membrane-based hybrid processes for high water recovery and selective inorganic pollutant separation.

The removal of heavy metals (e.g. Pb(II), Cd(II), Cu(II), etc.) and oxyanions (e.g. nitrate, As(III, V), Cr(VI), etc.) is of immense interest for treatment of groundwater and other dilute aqueous systems. However, the presence of non-toxic components, such as hardness (Ca, Mg) and sulfate, can interfere with the separation of toxic species. For example, pressure-driven membrane processes, such as reverse osmosis (RO), have been limited for water treatment due to problems that these extraneous components cause with water recovery and ionic strength (osmotic pressure) of the retentate. In addition, nitrate rejection by RO is considerably lower than NaCl rejection, resulting in permeate concentrations that may be too high for groundwater recharging. Other separation systems that rely solely on sorption of toxic species (e.g. ion exchange resins) may not have sufficient selectivity for efficient use in the presence of competing ions. Hence, implementation of pressure-driven membrane separations and high capacity sorbents in hybrid processes shows much promise for remedying these difficulties. For example, selective separation of nitrate may be achieved by combining nanofiltration (NF) for sulfate removal, followed by RO or ion exchange for nitrate removal (see example 1). When small concentrations of toxic metals are present, the large retentate volumes of RO processes may be reduced by selective removal of toxic species with a high capacity sorbent, thus permitting disposal of a lower volume, non-toxic stream (see example 2). The use of microfiltration membrane-based sorbents containing multiple polymeric functional groups is a novel technique to achieve high metal sorption capacity under convective flow conditions. These sorbents are formed by the attachment of various polyamino acids (MW: 2500-10,000), such as polyaspartic acid (cation sorption), polyarginine (oxyanion sorption), and polycysteine (chelation exchange), directly on the membrane pore surfaces. Since these sorbents have also been found to have high selectivity over non-toxic metals, such as calcium, they are ideal candidates for hybrid processing with RO/NF.

Adsorption↗

PubMed2002

The hatching of common carp (Cyprinus carpio L.) embryos in response to exposure to different concentrations of cryoprotectant at low temperatures.

The hatching performance of embryos of the common carp (Cyprinus carpio L.) was examined after 1, 7, 14, 21, or 28 days of storage at -8, -6, -4, -2, 0, 2, or 4 degrees C with different concentrations of methanol (0.5-7.0 M in 0.5 M steps) or varying concentrations of methanol in 0.1 M sucrose or trehalose. Preserved embryos failed to hatch after storage at -8 and -6 degrees C, regardless of the duration of storage or the concentrations tested. Likewise, there was no hatching out above 5.0 M concentration of methanol, even with the addition of sucrose or trehalose. After storage at 2 or 4 degrees C, the hatching rate was higher with mixtures of methanol (1.5 M) and trehalose (0.1 M) than with methanol plus sucrose or methanol alone. At 4 degrees C, the solution containing 1.5 M methanol supplemented with trehalose gave the highest hatching response of embryos stored for 14 days. Comparison of hatching after 24h of storage at the effective temperatures (-4, -2, 0, 2, and 4 degrees C) revealed that low concentrations of methanol were effective at high temperatures and high concentrations at sub-zero temperatures. The combination of 0.1 M trehalose with 1.5 M methanol gave the highest percentage hatching out both at 4 and 2 degrees C. At 0 degrees C, the highest percentage hatching occurred with 0.1 M trehalose plus 2.5 M methanol and at -2 and 4 degrees C, the best results were with 0.1 M trehalose plus 3.0 M methanol.

Animals↗