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Biomedical subjects

P Chattopadhyay

Publications and source records attributed to P Chattopadhyay.

At least 19 recordsLinked to original sources
PubMed2006

Drug encapsulation using supercritical fluid extraction of emulsions.

The current work was aimed at evaluating a new method, supercritical fluid extraction of emulsions (SFEE), for the production of composite (e.g., polymer-drug) micro- and nanoparticles, intended for application in sustained-release drug delivery formulations. Using the proposed method, composite particles were obtained, both in a continuous or batch manner by supercritical carbon dioxide extraction of oil-in-water (o/w) emulsions. Model drugs indomethacin and ketoprofen and biodegradable polymers poly(lactic/glycolic) acid and Eudragit RS were used in order to demonstrate the effectiveness of the SFEE process for producing these particles. Stable aqueous suspensions of composite micro and nanoparticles, having sizes ranging between 0.1 and 2 microm were consistently obtained. Emulsion droplet diameter was found to be the major size control parameter. Other parameters investigated included polymer and drug concentrations in solvent and emulsion solvent fraction. The residual solvent content in the particle suspension obtained was consistently below 50 ppm. Standard dissolution tests were used to observe the sustained release phenomenon of the composite particles. The dissolution profile was characterized in terms of the intrinsic dissolution kinetic coefficients taking into account the specific surface area and solubility of the particles. It was observed that the kinetic coefficient parameter for encapsulated drugs was reduced by 2-4 orders of magnitude when compared to the unprocessed drug particles.

Acetates↗
PubMed2005

RAPD & FINS (mitochondrial 16s rRNA gene sequence) in analysis of food contamination: detection of food poisoning by Lizard.

In poisoning, detection of the nature of causative agent is important for management of trauma and forensic investigation. Most of the methods in clinical toxicology are developed for detection of toxins and poisons. A random amplified polymorphic DNA (RAPD)-based method has been described for detection of species of animal from its morphologically unrecognizable fragments, recovered from food substances, consumption of which caused even death. Pre-mixed RAPD reaction beads and six RAPD primers were used in polymerase chain reaction analysis. Among six RAPD primers used, any one of them was sufficient in resolving this practical forensic situation. To enhance the probability values for matching in the present study of fixing identity of an animal, six set of market available RAPD primers were used. This is the first report of a forensic application of RAPD DNA typing in identification of charred skeleton remnants of Lizard species in food material. Furthermore unique amplicons were generated for different reptilian species, which can be used as species specific markers for species identification in forensic situation, however, no variations among individuals of same species were observed.

Animals↗
PubMed2004

Anti-inflammatory activity of tea (Camellia sinensis) root extract.

Pharmacological studies were carried out with methanol-water (1:1) extract of dried tea (Camellia sinensis) root extract (TRE). TRE was found to possess anti-inflammatory, analgesic and antipyretic activities at 1/10th of its LD50 dose of 100 mg/kg i.p. It was found that TRE inhibited the arachidonic acid-induced paw oedema in rats which indicated that TRE produced the anti-inflammatory activity by inhibiting both the cyclooxygenase and lypooxygenase pathways of arachidonic acid metabolism. TRE also enhanced peritoneal cell count and the number of macrophages in normal mice. It is plausible that the saponins present in TRE may be responsible for these activities of TRE.

Animals↗
PubMed2003

RAPD markers system as a useful tool for rapid identification of the origin of lizard contaminants in food.

In food poisoning, detection of the nature of causative agent is important for management of trauma and forensic investigation. Most of the methods in clinical toxicology are developed for detection of toxins and poisons. A RAPD-based method has been described for detection of species of animal from its morphologically unrecognizable fragments, recovered from food substances, consumption of which caused even death. Pre-mixed RAPD reaction beads and six RAPD primers were used in PCR analysis. Among six RAPD primers used, any one of them was sufficient in resolving this practical forensic situation. But to enhance the probability values for matching in the present study of fixing identity of an animal, six set of market available RAPD primers were used. This is the first report of a forensic application of RAPD DNA typing in identification of charred skeleton remnants of Lizard sp. in food material. Furthermore unique amplicons were generated for different reptilian species, which can be used as species specific markers for species identification in forensic situation, however no variations among individuals of same species were observed.

Animals↗
PubMed2002

Genetic polymorphism at nine microsatellite loci in four high altitude Himalayan desert human populations.

Allele frequencies for the nine STR loci of Profiler Plus STR markers were analyzed in 307 healthy unrelated individuals belonging to four predominant highly important endogamous population groups of Ladakh. The studied loci are found highly informative in human identification and understanding history of peopling of India. This is the first report on DNA Markers on any high altitude desert human population group.

Alleles↗
PubMed2002

A new improved method for extraction of DNA from teeth for the analysis of hypervariable loci.

A new method for better recovery of DNA suitable for amplification of hypervariable loci from fragments of teeth, consisting of two steps-scraping and aspiration, and extensive decalcification-is reported. Higher yields of high molecular weight DNA were obtained from the root, pulp, and crown of all kinds of 120 teeth, irrespective of gender, age, and source of teeth. HLA DQA1, 5 poly markers (LDLR, GYPA, HBGG, D7S8, and Gc), and other 12 short tandem repeat loci (HPRTB, F13B, LPL, D13S317, D7S820, D5S818, D21S11, D18S51, FGA, D8S1179, D3S1358, and vWA) could be successfully amplified and typed from recovered DNA.

Adolescent↗
PubMed2002

Patterns of genetic diversity at the nine forensically approved STR loci in the Indian populations.

Genetic diversity at the nine short tandem repeat (STR) loci, which are universally approved and widely used for forensic investigations, has been studied among nine Indian populations with diverse ethnic, linguistic, and geographic backgrounds. The nine STR loci were profiled on 902 individuals using fluorescent detection methods on an ABI377 System, with the aid of an Amp-F1 Profiler Plus Kit. The studied populations include two upper castes, Brahmin and Kayastha; a tribe, Garo, from West Bengal; a Hindu caste, Meitei, with historical links to Bengal Brahmins; a migrant group of Muslims; three tribal groups, Naga, Kuki and Hmar, from Manipur in northeast India; and a middle-ranking caste, Golla, who are seminomadic herders from Andhra Pradesh. Gene diversity analysis suggests that the average heterozygosity is uniformly high (>0.8) in the studied populations, with the coefficient of gene differentiation at 0.050 +/- 0.0054. Both neighbor-joining (NJ) and unweighted pair group method with arithmetic mean (UPGMA) trees based on DA distances bring out distinct clusters that are consistent with ethnic, linguistic, and/or geographic backgrounds of the populations. The fit of the Harpending and Ward model of regression of average heterozygosity on the gene frequency centroid is found to be good, and the observed outliers are consistent with the population structure and history of the studied populations. Our study suggests that the nine STR loci, used so far mostly for forensic investigations, can be used fruitfully for microevolutionary studies as well, and for reconstructing the phylogenetic history of human populations, at least at the local level.

Alleles↗
PubMed2001

Production of griseofulvin nanoparticles using supercritical CO(2) antisolvent with enhanced mass transfer.

Griseofulvin (GF) is a poor water soluble, antifungal agent. The bioavailability of the drug and its absorption from the gastrointestinal tract can be greatly improved by particle size reduction. In this work, supercritical antisolvent precipitation with enhanced mass transfer (SAS-EM) has been proposed for the production of GF nanoparticles. SAS-EM is a modification of the currently existing supercritical antisolvent (SAS) precipitation technique and also utilizes supercritical CO(2) as the antisolvent. In SAS-EM however, the solution jet is deflected by a surface vibrating at an ultrasonic frequency that atomizes the jet into small micro droplets. Further, the ultrasound field generated by the vibrating surface inside the supercritical media enhances mass transfer and prevents agglomeration due to increased mixing. GF nanoparticles of different sizes and morphologies have been obtained by varying the vibration intensity of the deflecting surface, which in turn is adjusted by changing the power supply to the attached ultrasound transducer. GF nanoparticles as low as 130 nm in size have been obtained corresponding to a power supply of 180 W. The effect of using different solvents on the size and morphology of the particles has also been studied.

Algorithms↗
PubMed2001

Distribution of alleles of three tetrameric STR loci HUMHPRTB, HUMF13B, HUMLPL and other six PCR based loci HLA DQA1, LDLR, GYPA, HBGG, D7S8, Gc in eight predominant populations of India.

Allele frequencies for the six PCR based loci HLA DQA1, LDLR, GYPA, HBGG, D&S8, Gc, and three STR loci HUMHPRTB, HUMF13B & HUMLPL were analyzed in 624 healthy unrelated individuals belonging to eight important population groups of two major ethnic populations: Indo-Caucasian and Indo-Mongoloid.

Alleles↗
PubMed2001

Effect of a rigid nonpolar solute on the splay, bend elastic constants, and on rotational viscosity coefficient of 4,4'-n-octyl-cyanobiphenyl.

The effect of a rigid nonpolar nonmesogenic solute "biphenyl," that is, C6H5-C6H5 on the splay and bend elastic constants and on the rotational viscosity coefficient of 4,4'-n-octyl-cyanobiphenyl is reported. The experiments involve the measurement of the voltage dependence of the capacitance of a cell filled with the mixture. Anomalous behavior of both K11 and Deltaepsilon near the N-S(A) transition have been observed.

Journal Article↗
PubMed2001

Analysis of sintered products of iron ore fines by flame atomic absorption spectrometry using a matrix modifier.

A very precise and accurate method for chemical analysis of sintered products (from iron ore fines in "pot grate furnace") is discussed. A matrix modifier/buffer (a mixture of KCl, tartaric acid, HCl and H2SO4) is used to prevent interference of iron in the determination of calcium and magnesium by flame atomic absorption spectrometry. Also, an EDTA titration method is recommended for calcium and magnesium after separating iron in the form of mixed oxides by ammonia-ammonium chloride buffer. Statistical data for a series of experiments are presented and precision values are found to be comparable with those of conventional methods used for complex metallurgical products. For the majority of cases, the agreement between the two methods is extremely good. A slight deviation has been noted in a few samples which may be overcome by a more thorough sampling prior to analysis.

Journal Article↗
PubMed2001

Genetic heterogeneity and alterations in chromosome 9 loci in a localized region of a functional pituitary adenoma.

The molecular alterations reported in pituitary adenomas include mutations at the G(s)alpha in somatotrophinomas, and hypermethylation of the p16 tumor suppressor gene. There are, however, no reports of genomic instability or intratumor genetic heterogeneity in pituitary adenomas. We have studied the microsatellite loci on the short arm of chromosome 9 (9p) and the DNA fingerprinting pattern, of adjacent compartments, about 2 mm across, in a functional chromophobe pituitary adenoma secreting growth hormone and prolactin. The microsatellite loci were studied by PCR amplification using locus specific primers, while the DNA fingerprinting pattern was studied by randomly amplified polymorphic DNA (RAPD) analysis. Normal leukocyte DNA was taken as control. Only one compartment (Ta) showed alterations in several of the microsatellite loci and in the RAPD pattern vis a vis corresponding normal DNA and also the other two compartments of the tumor. This provides evidence for the localized nature of genomic instability in this tumor.

Adenoma↗
PubMed2001

Examining the effects of work externalization through the lens of social identity theory.

This study examines whether dissimilarity among employees that is based on their work status (i.e., whether they are temporary or internal workers) influences their organization-based self-esteem, their trust in and attraction toward their peers, and their altruism. A model that is based on social identity theory posits that work-status dissimilarity negatively influences each outcome variable and that the strength of this relationship varies depending on whether employees have temporary or internal status and the composition of their work groups. Results that are based on a survey of 326 employees (189 internal and 137 temporary) from 34 work groups, belonging to 2 organizations, indicate that work-status dissimilarity has a systematic negative effect only on outcomes related to internal workers when they work in temporary-worker-dominated groups.

Adult↗
PubMed2000

Synthesis and structural characterization of a Re(V) complex with a 2N1S donor and the radiochemical behavior of its Tc analog.

A rhenium(V) complex with 2-(2-pyridylmethylthio)-aniline has been synthesized and characterized by UV-VIS absorption, IR, MS and X-ray crystallography. The complex contains a ReO3+ moiety and the amine compound, acting as a monobasic tridentate(NSN) ligand. The chemical behavior of its technetium analog has been studied radioanalytically by solvent extraction, TLC, electrophoresis and HPLC using 99mTc tracer.

Crystallography, X-Ray↗