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Biomedical subjects

I Roy

Publications and source records attributed to I Roy.

At least 19 recordsLinked to original sources
PubMed2006

Polyhydroxyalkanoate (PHA) biosynthesis from structurally unrelated carbon sources by a newly characterized Bacillus spp.

A newly acquired polyhydroxyalkanoate (PHA) producing Bacillus spp. was identified to be a strain of Bacillus cereus using a range of microbiological and molecular techniques. This strain, named B. cereus SPV, was found to be capable of using a wide range of carbon sources including glucose, fructose, sucrose, various fatty acids and gluconate for the production of PHAs, an advantage for the commercial production of the polymers. The media used for the polymer production was novel in the context of the genus Bacillus. The PHA, once produced, was found to remain at a constant maximal concentration, without any degradation, a great advantage for the commercial production of the PHAs. This particular strain of Bacillus spp. was able to synthesize various PHAs with 3-hydroxybutyrate (3HB), 3-hydroxyvalerate (3HV) and 4-hydroxybutyrate (4HB)-like monomer units from structurally unrelated carbon sources such as fructose, sucrose and gluconate. This is the first report of the incorporation of a 4HB related monomer containing PHA by the genus Bacillus and from structurally unrelated carbon sources. The PHAs isolated had molecular weights ranging between (0.4 and 0.8) x 10(6) and low polydispersity index values (M(W)/M(N)) ranging from 2.6 to 3.4.

Bacillus cereus↗
PubMed2006

Lack of influence of COMT and NET genes variants on executive functions in schizophrenic and bipolar patients, their first-degree relatives and controls.

Abnormal dopaminergic function in the prefrontal cortex (PFC) may be a key factor in the etiopathogeny of schizophrenia and bipolar disorder. Both schizophrenic and bipolar subjects have executive functions (EF) deficits, thought to reflect abnormal PFC function. The main inactivation pathways for dopamine in the PFC are enzymatic cleavage by the Carboxy-O-Methyl-Transferase (COMT) and reuptake by the nor-epinephrine transporter (NET). Our aim in this study was to replicate previous studies that investigated influence of the COMT genotype on EF in schizophrenic subjects, their relatives and controls and extend their scope by including bipolar patients, and their relatives and by exploring NET gene polymorphisms influence on executive performances. We investigated one functional polymorphism of the COMT gene and two polymorphisms of the NET gene. EF were assessed by means of the Trail Making Test (TMT) and the Wisconsin Card Sorting Test (WCST). We assessed the effect of each of the three genotypes on EF for the whole sample (N = 318) and separately in schizophrenic (N = 66), bipolar (N = 94) and healthy subjects (i.e., relatives and controls N = 158). Separate analyses were performed because of the presence, in patients samples, of potentially confounding factors, especially medication. Genotype had no significant effect on the cognitive measures in any of the analyses (for the two EF measures, the three polymorphisms, and the four groups). In our sample we found no evidence in favor of a major effect of COMT or NET polymorphisms on the two tests of EF.

Adult↗
PubMed2006

Phoenix sylvestris Roxb pollen allergy: a 2-year randomized controlled trial and follow-up study of immunotherapy in patients with seasonal allergy in an agricultural area of West Bengal, India.

BACKGROUND: Although the efficacy of allergen immunotherapy has been demonstrated in seasonal pollen allergy, there is no report of a double-blind placebo-controlled trial with standardized pollen extract in seasonal respiratory allergy from India. In the agricultural area of eastern India, Phoenix sylvestris Roxb or date sugar palm is grown or cultivated and seasonal allergic rhinitis is common during the pollen season. OBJECTIVE: The objective of the present study was to observe the clinical and immunological changes during a 2-year double-blind placebo-controlled trial of immunotherapy with standardized P sylvestris pollen extract in respiratory patients sensitive to pollen from this wild date palm. Thirty-five subjects with typical seasonal allergic rhinitis with or without bronchial asthma were selected. A symptom-medication score (based on a questionnaire and diary) was correlated with pollen counts as recorded in a Burkard sampler. Eighteen subjects were randomized to a specific immunotherapy (SIT) group receiving regular injections containing standardized allergen extract and 17 to a placebo control group. Changes in the level of specific immunoglobulin (Ig) E, IgG1, and IgG4 were recorded at 3-month intervals. Measurement of wheal diameter, total IgE level and forced expiratory volume in 1 second (FEV1) were performed before starting and a month after finishing therapy. RESULTS: The SIT group showed decreases of 33.5% and 57% from the baseline symptom-medication scores during the first and second treatment season, respectively. This group showed significant decreases in skin-reactivity to P sylvestris pollen extract and in specific IgE levels, and significant increases in FEV,, specific IgGI (1.95-3.2 times higher) and IgG4 (21.24-30.83 times higher). There were no significant changes in total IgE levels. The control group showed no significant changes for any parameter except the development of new sensitization in 2 cases (to Saccharum officinarum pollen grain and Alternaria species spores). The rate of local adverse reactions was 0.024%. CONCLUSION: After a 2-year study, allergen immunotherapy with standardized P sylvestris pollen extract was found to be effective in seasonal respiratory allergic subjects susceptible to P sylvestris pollen with a narrow range of sensitization.

Adult↗
PubMed2005

Aerobiological and immunochemical studies on Carica papaya L. pollen: an aeroallergen from India.

BACKGROUND: Carica papaya L. is a fruit yielding tree, wildly grown or cultivated in the tropics and subtropics. Its pollen grain has been reported to be airborne and cause immunoglobulin E (IgE)-mediated hypersensitivity. OBJECTIVE: To conduct long-term aerobiological study on Carica pollen, along with aeroallergenic particles originating from it and to identify vis-a-vis characterize an important IgE-reactive component present in this pollen. METHODS: The seasonal and diurnal periodicities of airborne C. papaya pollen were recorded in a 5-year survey using a Burkard volumetric sampler. The allergenic potential was studied by skin prick tests, IgE-enzyme-linked immunosorbent assay (ELISA) and also by aeroallergen immunoblotting. The total pollen extract was fractionated by Sephacryl S-200 column, and out of the eluted five fractions, the maximum IgE-reactive fraction (as found in ELISA inhibition) was resolved into five major subfractions in reverse-phase high-performance liquid chromatography (RP-HPLC). The subfraction with optimum IgE reactivity was studied by activity gel, native and nonreducing sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). The homogeneity of the isolated protein fraction was checked by crossed immunoelectrophoresis with rabbit antisera and IgE reactivity was confirmed by ELISA inhibition and immunoblotting using individual patient sera. RESULTS: The Carica pollen occurred in the air round the year with peaks during January and September-October. Among a patient population of 1000, skin-test results showed 27.8% +1 level and 5.6% +2/+3 level reactions. In aeroallergen immunoblotting of exposed Burkard tape segments, the detected allergen spots showed a significant correlation with airborne pollen count recorded. The pollen extract elicited loss of IgE reactivity when treated with reducing agent-like beta-mercaptoethanol and heat, but showed six IgE-reactive components in nonreducing IgE-immunoblot. The fraction 1 eluted from Sephacryl S-200 column showed highest IgE reactivity and resolved into five major components in RP-HPLC. Out of these, the fraction showing optimum IgE reactivity in IgE-ELISA inhibition and immunoblotting with patient antisera, elicited esterase activity and found to be a homogenous protein of 100 kDa. CONCLUSION: Carica papaya tree contributes significantly to the aeropollen and aeroallergen load of the suburban outskirts of Calcutta metropolis, India. The pollen extract contains an important IgE-reactive protein component of 100 kDa molecular weight with esterase activity.

Adult↗
PubMed2004

Assessment of allergenicity to Mallotus phillipensis pollen in atopic patients in India: a new allergen.

OBJECTIVE: Pollen grains of the Euphorbiaceae family are well known causative agents of respiratory allergies in India, European countries and USA. Mallotus phillipensis belongs to the same family and may have some common allergenic properties. It has thus been evaluated for the first time in Indian population for its pollinosis causing properties. METHODS: Pollen antigen of Mallotus phillipensis (MP) was extracted and characterized for its protein components by biochemical methods. Pollinosis potency of crude extract of MP pollen was evaluated by skin prick test on population residing in different parts of India. Specific IgE binding characteristics of the extract were determined by ELISA and Immunoblot. RESULTS: Marked skin reactivity in 5.7% atopic population was recorded and subjects constituting 23.8% of the total patients tested showed skin sensitivity to the MP pollen antigen. Significantly raised specific IgE against MP pollen were recorded in 50% of the skin test positive patients. A number of protein bands were detected in a wide Molecular weight range as well as in acidic pI range, by SDS-PAGE and IEF, respectively. A total 11 protein fractions were detected by the specific IgE antibodies on immunoblotting with patient's sera and were considered allergenic. CONCLUSION: Patients from different geographical regions have shown sensitization to MP pollen antigen. Many proteins have similar molecular weights and pI as other allergenic members of the family (Ricinus communis and Putranjiva roxburghii) found in India, which constitutes a good reason for studying cross reactivity among the members of family Euphorbiaceae, in the future.

Allergens↗
PubMed2003

Magnetic alginate microparticles for purification of alpha-amylases.

Spherical magnetic alginate microparticles (25-60 microm in diameter) were prepared using the microemulsion system, with water-saturated 1-pentanol as the organic phase. The limited solubility of 1-pentanol in water enabled simple removal of the organic solvent from the prepared beads with water solution. The prepared alginate microparticles were used as magnetic affinity adsorbents for specific purification of alpha-amylases. Enzyme activity was eluted by 1.0 M maltose. alpha-Amylases from Bacillus amyloliquefaciens and porcine pancreatic acetone powder were purified 9- and 12-fold with 88 and 96% activity recovery, respectively.

Alginates↗
PubMed2003

Immobilization of xylan-degrading enzymes from Melanocarpus albomyces IIS 68 on the smart polymer Eudragit L-100.

Xylanase of Melanocarpus albomyces IIS 68 was immobilized on Eudragit L-100. The latter is a copolymer of methacrylic acid and methyl methacrylate and is a pH-sensitive smart polymer. The immobilization was carried out by gentle adsorption and an immobilization efficiency of 0.82 was obtained. The enzyme did not leach off the polymer even in the presence of 1 M NaCl and 50% ethylene glycol. The K(m) of the enzyme changed from 5.9 mg ml(-1) to 9.1 mg ml(-1) upon immobilization. The V(max) of the immobilized enzyme showed an increase from 90.9 micro mol ml(-1) min(-1) (for the free enzyme) to 111.1 micro mol ml(-1) min(-1). The immobilized enzyme could be reused up to ten times without impairment of the xylanolytic activity. The immobilized enzyme was also evaluated for its application in pre-bleaching of eucalyptus kraft pulp.

Enzymes, Immobilized↗
PubMed2003

A consensus development approach to define national research priorities in bone metastases: proceedings from NCIC CTG workshop.

AIMS: A 1-day workshop was conducted to gather interested Canadian radiation oncologists to identify priority research questions that could be answered through clinical trials under the auspices of the National Cancer Institute of Canada--Clinical Trials Group (NCIC-CTG) Symptom Control committee. MATERIALS AND METHODS: In preparation for the workshop, a survey of Canadian radiation oncologists resulted in four research areas in symptom control, including radiation-induced mucosal reactions, fatigue, radiotherapy for brain metastases and radiotherapy for bone metastases. The first half of the workshop consisted of plenary sessions where the research setting and perspective was defined for each area. This was followed by deliberations by a subgroup of researchers with special interest in the topic area. The bone-metastases subgroup deliberated the clinical context, the scientific merits and the required methodology of research questions related to the role of radiotherapy in early treatment of bone metastases, the role of re-irradiation, the role of systemic radiotherapy and patient selection for different fractionation schedules. A list of prioritised clinical studies was proposed. RESULTS: The question of single vs multi-fraction re-irradiation for symptomatic bone metastases was identified as most pertinent to the Canadian radiation oncologists present. A multi-centre, international intergroup study is undergoing protocol development. Other study concepts, such as an alternative dose-schedule of 17 Gy/2 fractions/1 week for intermediate-prognosis patients, and early referral for radiation oncologist assessment of early or mildly symptomatic bone metastases for good-prognosis patients, require further methodological development before a clinical trial can be proposed. CONCLUSION: An NCIC-CTG workshop provided an update on current evidence-based knowledge in palliative radiotherapy for bone metastases. New trial concepts were discussed among practitioners and clinical investigators to promote dialogue and collaboration. The proposal of an international intergroup randomised trial of single vs multiple fraction re-irradiation for painful bone metastases received the most support among participants.

Bone Neoplasms↗
PubMed2003

pH-responsive polymer-assisted refolding of urea- and organic solvent-denatured alpha-chymotrypsin.

A pH-responsive polymer Eudragit S-100 has been found to assist in correct folding of alpha-chymotrypsin denatured with 8 M urea and 100 mM dithiothreitol at pH 8.2. The complete activity could be regained within 10 min during refolding. Both native and refolded enzymes showed emission of intrinsic fluorescence with lambda(max) of 342 nm. Gel electrophoresis showed that the presence of Eudragit S-100 led to dissociation of multimers followed by the appearance of a band at the monomer position. The unfolding (by 8 M urea) and folding (assisted by the polymer) also led to complete renaturation of alpha-chymotrypsin initially denatured by 90% dioxane. The implications of the data in recovery of enzyme activity from inclusion bodies and the interesting possibility in the in vivo context of reversing protein aggregation in amyloid-based diseases have been discussed.

Chymotrypsin↗
PubMed2001

The impact of skin washing with water and soap during breast irradiation: a randomized study.

BACKGROUND: The effect of washing the irradiated skin during radiotherapy for breast cancer is uncertain. The purpose of this study was to evaluate the impact of washing the breast skin with water and soap during radiotherapy on the intensity of acute skin toxicity. MATERIALS AND METHODS: Ninety-nine patients treated for breast cancer were prospectively randomized prior to receiving radiotherapy to the breast into two groups: (1), no washing was allowed during radiotherapy (49 patients); and (2), washing was allowed with water and soap (50 patients). Acute toxicity was recorded according to the Radiation Therapy Oncology Group (RTOG) acute skin toxicity scale for each patient every week during radiotherapy and 1 month after the end of radiotherapy. Symptoms related to skin toxicity were scored by visual analogue scales at the same time intervals. Other data collected included sociodemographic data, characteristics related to the tumor and previous treatments, radiation technique, necessity for a second simulation due to loss of skin marks and treatment interruptions. RESULTS: In the non-washing group, the following maximum acute toxicity scores were observed: grade 0, 2%; grade 1, 41%; grade 2, 57%; grades 3 and 4, 0%. For the washing group, the scores were: grade 0, 0%; grade 1, 64%; grade 2, 34%; grade 3, 2%; and grade 4, 0%. Moist desquamation was seen in 33% of non-washing patients, but in only 14% of washing patients. The median scores of pain, itching and burning of the treated skin were higher in the non-washing group, although this was not statistically significant. In a multivariate analysis using logistic regression, acute skin toxicity was associated with the patient's weight, concomitant radiochemotherapy and hot spots on dosimetry, and there was a trend toward more acute skin toxicity in the non-washing group. CONCLUSION: Washing the irradiated skin during the course of radiotherapy for breast cancer is not associated with increased skin toxicity and should not be discouraged.

Acute Disease↗
PubMed2001

Ethical considerations in the use of lentiviral vectors for genetic transfer.

This chapter will outline the various concerns which have been raised in scientific, bioethics, and lay communities about the use of lentiviral vectors for purposes of gene therapy. Many of these concerns are ranged around gene therapy itself; others are concerns particular to using this sort of vector for genetic modification of human cells. These concerns are outlined within the chapter, and arguments are given in favor and against various approaches to these concerns. Lastly, it is noted throughout that at this stage of research into gene therapy, the most practical approach to these dilemmas is to maintain awareness of the ethical problems and provide information to those concerned with all aspects of the development of this set of technologies.

Animals↗
PubMed2001

Enhancement of enzyme activity through three-phase partitioning: crystal structure of a modified serine proteinase at 1.5 A resolution.

Three-phase partitioning is fast developing as a novel bioseparation strategy with a wide range of applications including enzyme stability and enhancement of its catalytic activity. Despite all this, the enzyme behaviour in this process still remains unknown. A serine proteinase, proteinase K, was subjected to three-phase partitioning (TPP). A 3 ml volume of proteinase K solution (3 mg/ml in 0.05 M acetate buffer, pH 6.0) was brought to 30% (w/v) ammonium sulphate saturation by addition of saturated ammonium sulphate. tert-Butanol (6 ml) was added to this solution and the mixture was incubated at 25 degrees C for 1 h. The precipitated protein in the mid-layer was dissolved in 3 ml of 0.05 M acetate buffer, pH 6.0. The specific activity of the processed enzyme was estimated and was found to be 210% of the original enzyme activity. In order to understand the basis of this remarkable enhancement of the enzyme activity, the structure of the TPP-treated enzyme was determined by X-ray diffraction at 1.5 A resolution. The overall structure of the TPP-treated enzyme is similar to the original structure in an aqueous environment. The hydrogen bonding system of the catalytic triad is intact. However, the water structure in the substrate binding site has undergone a rearrangement as some of the water molecules are either displaced or completely absent. Two acetate ions were identified in the structure. One is located in the active site and seems to mimic the role of water in the enzyme activity and stability. The other is located at the surface of the molecule and is involved in stabilizing the local structure of the enzyme. The most striking observation in respect of the present structure pertains to a relatively higher overall temperature factor (B = 19.7 A(2)) than the value of 9.3 A(2) in the original enzyme. As a result of a higher B-factor, a number of residues, particularly their side chains, were found to adopt more than one conformation. It appears that the protein exists in an excited state which might be helping the enzyme to function more rapidly than the original enzyme in aqueous media. Summarily, the basis of increased enzymatic activity could be attributed to (i) the presence of an acetate ion at the active site and (ii) its excited state as reflected by an overall higher B-factor.

Crystallography, X-Ray↗
PubMed2001

Ovarian pathology and high incidence of sex cord tumors in follitropin receptor knockout (FORKO) mice.

In this investigation we describe our observations of the status of the aging ovary in mice with disruption of the receptor for FSH. Knockout mice at 3-5 months of age are acyclic and sterile, with very small, underdeveloped ovaries. Thus, they exhibit hypergonadotropic-hypogonadism with high levels of circulating FSH similar to the postmenopausal state in women. By 12 months more than 92% of these animals developed various kinds of ovarian pathology, including neoplasms of sex cord-stromal type as well as cysts. Interestingly, the majority of tumors were located in the right ovary, with the contralateral ovary remaining unaffected but atrophic. The ovary from heterozygotes also showed pathology after 15 months. None of the age-matched wild-type mice that remained fertile developed any sign of ovarian tumors. Circulating LH and FSH levels were increased in follitropin receptor knockout mice and remained severalfold higher in tumor-bearing animals. The histological appearances of ovarian tumors were similar to the pathology observed in some types of sex cord-stromal neoplasms in women. The tumor burden caused weight loss and cachexia in follitropin receptor knockout mice. Based on these characteristics as well as the high incidence of ovarian pathology in the aging mutant, we propose that the loss of the FSH receptor signaling mechanisms predispose the ovary to molecular and structural changes leading to tumor formation. Hence, in the intact and fertile animal, FSH receptor signaling offers a protective mechanism that is lost upon reproductive senescence (menopause in women). Further studies are warranted in this genetic model to explore the molecular changes underlying the development of ovarian neoplasia.

Animals↗
PubMed2001

Accidental germ-line modifications through somatic cell gene therapies: some ethical considerations.

Proposed somatic cell gene-therapies (especially those involving in utero therapies) may involve a small risk of germ-line modifications; this risk has engendered serious concern, and arguments have been made that such therapies ought not be pursued if such risks exists. We argue here that while pursuing deliberate germ-line modifications in humans would be inappropriate given the current state of the art, the risk of accidental germ-line modifications from most currently proposed in utero gene therapy is no different in kind or degree from other risks regularly taken in medical procedures. Given the possible benefits of such therapies, we argue that the risk of accidental germ-line modifications is well worth taking in these cases.

Genetic Engineering↗
PubMed2000

Simultaneous purification and immobilization of Aspergillus niger xylanase on the reversibly soluble polymer Eudragit(TM) L-100.

The non-covalent immobilization of a commercial preparation of xylanase from A. niger was carried out on a reversibly soluble-insoluble enteric polymer Eudragit(TM) L-100. The immobilization of the xylanase activity by adsorption was simultaneously accompanied by removal of cellulase activity since the latter did not bind to the polymer. Thus, the soluble enzyme derivative may be useful for treatment of paper pulp bleaching in paper industry. The immobilized xylanase retained 60% of its activity toward xylan as the substrate. No change was observed in the pH optimum (5.5) of the enzyme upon immobilization. Only marginal increase in the K(m) of the free enzyme (3.6 mg ml(-1) to 5.0 mg ml(-1)) upon immobilization on the soluble polymer reflected that the enzyme-substrate binding continues to be efficient in spite of the macromolecular nature of the substrate. Fluorescence spectroscopy and UV difference spectroscopy were used to probe the change(s) in the enzyme structure upon immobilization. This change in structure was correlated with the "effectiveness factor" of the enzyme activity. CD spectra also showed that the enzyme undergoes drastic changes in the structure.

Journal Article↗
PubMed2000

Exploiting unusual affinity of usual polysaccharides for separation of enzymes on fluidized beds.

Two polysaccharides, alginate and chitosan, showed unusual affinity and bound alpha-amylase (from various sources) and Aspergillus niger cellulase, respectively. The beads prepared from these polymers were successfully used for the purification of the respective enzymes by fluidized bed affinity chromatography. alpha-amylase from wheat germ could be purified by 58-fold with about 90% recovery of activity. Aspergillus niger cellulase, on the other hand, was purified by 30-fold with 80% recovery of enzyme activity. Both purified preparations show single band on SDS-PAGE.

Journal Article↗