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Biomedical subjects

S Sengupta

Publications and source records attributed to S Sengupta.

At least 145 records · Page 8Linked to original sources
PubMed1996

Physical map of the genome of Vibrio cholerae 569B and localization of genetic markers.

A combined physical and genetic map of the genome of the classical O1 hypertoxinogenic strain 569B of Vibrio cholerae has been constructed. The enzymes NotI, SfiI and CeuI generated DNA fragments of suitable size distribution that could be resolved by pulsed-field gel electrophoresis. The digests produced 37, 22, and 7 fragments, respectively. The CeuI maps of the genomes of strains 569B and O395, constructed by partial restriction digestion, were identical, and the data are consistent with the concept of circular chromosomes. The genome size of each of the strains was estimated to be about 3.2 Mb. The NotI and SfiI digestion profiles of the genomic DNAs of strains 569B and O395 exhibited distinct restriction fragment length polymorphism. The linkages between the 37 NotI fragments of the genome of strain 569B were determined by combining three approaches: isolation of linking clones, analysis of partial digestion fragments, and identification of NotI fragments in isolated CeuI and SfiI fragments. To align linked fragments precisely, NotI-digested genomic DNA was end labeled and separated in the same gel with the NotI-digested DNA to be probed with linking clones. This also allowed the identification of smaller restriction fragments that are not visible in ethidium bromide-stained gels. The presence of repetitive DNA sequences in the V. cholerae 569B genome has been demonstrated. Twenty cloned homologous and heterologous genes and seven rrn operons have been positioned on the physical map. The two copies of the Ctx genetic element in the genome of strain 569B are located about 1,000 kb apart.

Base Sequence↗
PubMed1996

Variation of serum potassium and creatinine phosphokinase levels in suxamethonium-induced muscle relaxation.

Popular depolarising muscle relaxant, suxamethonium (succinylcholine chloride), produces fasciculation in group of muscles and 'after pain'. Mode of its action is neuromuscular blockage. It also may be associated with muscle fibre injury and altered membrane permeability. These may cause rise of serum K+ and creatinine phosphokinase (CPK) levels. But use of diazepam either during or as pretreatment may reduce the fasciculation, 'after pain' and rise of K+ and CPK levels. Present study was undertaken to show whether any correlation of the degree of fasciculation and postsuxamethonium myalgia is present or not and whether diazepam has any role in reducing muscle injury and in turn reducing the levels of serum K+ and CPK.

Adult↗
PubMed1996

Variation in menarcheal age of Assamese girls.

The onset of menarche of 571 Assamese girls was investigated and the study sample included individuals from the population of various Assamese castes (brahmin, kalita, kaibarta), the Muslims and from the 2 Mongoloid populations, ie, the ahoms and the sonowals of Assam. Attempt was made to ascertain inter-group differences among themselves. The study revealed that there was insignificant statistical variation among the populations under consideration. Finally, the present findings were compared to that of the mean menarcheal age obtained on the same population by the earlier researchers which revealed good deal of variation among them. Secular trend in the age at menarche among these populations are discussed. Evidence of steady fall of menarcheal age in several populations has been noted in the present study.

Age Factors↗
PubMed1996

Induction of apoptosis by ionizing radiation in Chinese hamster V79 cells and a radioresistant cell strain derived from V79.

DNA fragmentation into nucleosome ladder, a hall mark of apoptosis, could be obtained by as low as 0.58 Gy of gamma irradiation within 6 hr of irradiation which increased appreciably after 48 hr in V79 cells. In the same condition condensation of the nucleus and marginalization of the cytoplasm the characteristic morphology of apoptotic death were observed. Unirradiated controls had approximately 2% apoptotic cells. When cells were irradiated with 0.58 Gy, approximately 10% of the cells had the apoptotic morphology. This number increased to approximately 29% at 3.5 Gy dose. At a higher dose, apoptotic and necrotic cells were visualized. In radio resistant cells higher doses were required to induce morphological changes. The results indicated that gamma irradiation can induce apoptosis in Chinese hamster V79, fibroblast cell line and the radioresistant cell strain derived from V79 cells is also resistant to induction of apoptosis.

Animals↗
PubMed1996

Possible role of glutathione in resistance to heavy metals and hydrogen peroxide in a radioresistant Chinese hamster V79 cell strain.

To understand the cellular and biochemical nature of radioresistance in the strain M5 derived from Chinese hamster V79 cells, the sensitivity of the resistant cells towards CdCl2, Zn(Ac)2, and H2O2 by the colony forming ability has been tested. D0 values for these compounds in Chinese hamster V79 cells were 5.4 microM, 27.8 microM and 4.3 micrograms/ml respectively while for M5 cells these were 8.3 microM, 142.9 microM and 11.9 micrograms/ml respectively. The resistance to heavy metals as well as the oxidative damage could be reversed by the inhibition of glutathione synthesis by the drug buthionine sulfoximine (BSO). These set of data indicate that the cellular antioxidant glutathione plays an important role in the observed oxidant-resistant phenotype as well as heavy metal resistance in M5 cells.

Animals↗
PubMed1996

Localization of platelet-derived growth factor beta receptor expression in the periepithelial stroma of human breast carcinoma.

Platelet-derived growth factor (PDGF) BB is secreted by most human breast carcinoma cells; however, only recently have PDGF beta receptors been demonstrated in malignant breast tissue. In the present study, the tissue localization of PDGF beta receptor expression was studied in human breast carcinoma and nonmalignant breast tissues stained using both immunofluorescence and immunoperoxidase techniques. We examined a total of 29 cases of breast carcinomas, which showed both in situ and invasive components. PDGF beta receptor staining was localized in the periepithelial stroma and was particularly intense in regions immediately adjacent to carcinoma in situ components in all tumors examined. A diffuse low level of PDGF beta receptor staining was seen throughout the stroma of eight nonmalignant breast tissues as well as of nonmalignant regions of tumor tissues. Image analysis was used to assess the coincidence of staining of PDGF beta receptor with epithelial or stromal cells in 13 of the 29 tumor tissues studied. Less than 5% of malignant ductal epithelium or myoepithelium showed PDGF beta receptor staining. Analysis with stromal cell type-specific markers indicated significant localization of PDGF beta receptor primarily within alpha smooth muscle actin-staining cells (32%) and vascular endothelial cells (41%) in the periepithelial stroma. PDGF beta receptor positivity was strongly associated with periepithelial stromal cells adjacent to the basement membrane surrounding regions of carcinoma in situ but was less intense in regions of invasive carcinoma where basement membrane was degraded. The absence of PDGF beta receptors on carcinoma cells and their presence in the surrounding stroma suggest a paracrine stimulation of adjacent stromal tissue by malignant epithelial cells in human breast tumors.

Actins↗
PubMed1995

Interaction of a fluorescent paclitaxel analogue with tubulin.

To study the mechanism of binding of the antitumor agent paclitaxel to microtubules and tubulin, we have synthesized a fluorescent analogue of the drug. A dimethylamino group was introduced onto the 3'-N-benzoyl group of paclitaxel. This compound was synthesized from N-debenzoylpaclitaxel and 3-(dimethylamino)benzoyl chloride in 67% yield. N-Debenzoyl-N-[3-(dimethylamino)benzoyl]-paclitaxel has activity similar to paclitaxel in inducing microtubule assembly and binds to tubulin at the paclitaxel-binding site. Under assembly conditions, binding of this paclitaxel analogue to tubulin occurs in a time-dependent manner and is accompanied by a large increase in fluorescence intensity, as well as a large blue shift in the emission maximum. In addition, evidence is presented to show that this compound also binds to tubulin in the dimeric state, but the binding affinity is much lower (Kd = 49 +/- 8 microM at 25 degrees C) than that reported for polymeric tubulin. The fluorescent paclitaxel analogue, with a high quantum yield, will be a useful tool in studying the mechanism of paclitaxel binding to tubulin and the environment of the paclitaxel-binding site on tubulin.

Animals↗
PubMed1995

Interaction of a fluorescent analog of N-deacetyl-N-methyl-colchicine (colcemid) with liver alcohol dehydrogenase.

The evidence for specific binding of N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)--colcemid (NBD-colcemid), a fluorescent analog of colcemid (N-deacetyl-N-methyl-colchicine), to liver alcohol dehydrogenase is presented. Alcohol dehydrogenase bound NBD-colcemid in a time-dependent manner, enhanced the fluorescence intensity, and caused a large blue shift of the emission maximum of the free drug. The specificity of binding was determined for both the colchicine nucleus and the NBD moiety. The binding was not affected by the presence of alcohol or NAD in the reaction mixture. Preincubation of horse liver alcohol dehydrogenase with colcemid inhibited the binding to a considerable extent. NBD-colcemid inhibited the enzymic activity of alcohol dehydrogenase in a mixed-type noncompetitive mode with a Ki value of 32 microM, whereas colcemid showed noncompetitive inhibition with a Ki of 100 microM. The association rate constant of NBD-colcemid binding with liver alcohol dehydrogenase was 587 M-1 s-1 at 25 degrees C. The stoichiometry and dissociation constant of the binding reaction were 0.62/dimer and 12 microM, respectively. Donor quenching experiments showed that both tryptophans of alcohol dehydrogenase transferred energy to the bound NBD-colcemid. Thus, this study reports the binding of a colchicine analog to a protein other than tubulin with high affinity. It is concluded that NBD-colcemid binding to dehydrogenases is a general phenomenon, but the common structural element(s) that is responsible for the binding activity, and which exists among tubulin and dehydrogenases, has yet to be determined.

Alcohol Dehydrogenase↗
PubMed1995

Heat, hydrogen peroxide, and UV resistance of Bacillus subtilis spores with increased core water content and with or without major DNA-binding proteins.

Spores of a Bacillus subtilis strain with an insertion mutation in the dacB gene, which codes for an enzyme involved in spore cortex biosynthesis, have a higher core water content than wild-type spores. Spores lacking the two major alpha/beta-type small, acid-soluble proteins (SASP) (termed alpha-beta- spores) have the same core water content as do wild-type spores, but alpha-beta- dacB spores had more core water than did dacB spores. The resistance of alpha-beta-, alpha-beta- dacB, dacB, and wild-type spores to dry and moist heat, hydrogen peroxide, and UV radiation has been determined, as has the role of DNA damage in spore killing by moist heat and hydrogen peroxide. These data (i) suggest that core water content has little if any role in spore UV resistance and are consistent with binding of alpha/beta-type SASP to DNA being the major mechanism providing protection to spores from UV radiation; (ii) suggest that binding of alpha/beta-type SASP to DNA is the major mechanism unique to spores providing protection from dry heat; (iii) suggest that spore resistance to moist heat and hydrogen peroxide is affected to a large degree by the core water content, as increased core water resulted in large decreases in spore resistance to these agents; and (iv) indicate that since this decreased resistance (i.e., in dacB spores) is not associated with increased spore killing by DNA damage, spore DNA must normally be extremely well protected against such damage, presumably by the saturation of spore DNA by alpha/beta-type SASP.

Bacillus subtilis↗
PubMed1995

Balanced incomplete block design: description, case study, and implications for practice.

This article discusses the use of balanced incomplete block design for process evaluation and presents a case study of its use. This technique produces a weighted ranking of program elements, showing the relative importance of each element and allowing comparison of process and content elements. The article presents a case study in which the technique was used to evaluate the Chronic Disease Self-Management Program. Participants and lay course leaders were asked to rank 13 course elements for their helpfulness. The most valued element, sharing or unstructured interactions among participants, was not an explicitly planned part of the intervention. Some of the elements least valued (nutrition, use of community resources, and medication use) are elements most emphasized by the health care system and by patient education. We found that balanced incomplete block design was easy to administer and tally. The results could be readily applied to program redesign and to needs assessment.

Activities of Daily Living↗
PubMed1995

Applying a controlled medical terminology to a distributed, production clinical information system.

To maximize the value of computerized medical records systems, an organizing structure is needed. That structure can be provided by a controlled medical terminology (CMT). At Columbia-Presbyterian Medical Center, we have been employing a controlled medical terminology, our Medical Entities Dictionary (MED), to mediate the storage and retrieval of patient data and enable decision support applications. This paper describes how the MED is actually used for data management in our distributed clinical information systems environment. Our system tools which access the MED for production purposes facilitate the mapping of terms from many sources to a uniform representation of concepts and also return information about the relationships between concepts. Applications which access a CMT for production purposes should be optimized for performance in high volume settings, fault tolerant, synchronizable, extensible, portable, and maintainable. We briefly describe our system architecture and then demonstrate how we utilize the MED for translation and semantic information as data is moved into and out of our patient database. We discuss our current tools and present a preview of the next generation of applications which will manage access to the MED for our production systems.

Computer Communication Networks↗
PubMed1995

The role of the information architect at King Faisal Specialist Hospital and Research Centre.

Successful implementation of integrated clinical information system requires modification of the institution's long range strategic plans and its personnel's behavior. The changes warrant a concerted effort on the part of many different individuals; this paper describes the role of the Information Architect whose primary functions are to steer the process to fulfill stated objectives and build consensus where divergent forces are at work. The workings of the Architect is presented in context of a unique Middle-Eastern institution currently undergoing automation of clinical information.

Academic Medical Centers↗
PubMed1995

Role of nitrogen fixing bacteria on the phyllosphere of wheat seedlings.

Two diazotrophic bacteria Azotobacter chroococcum (REN2) and Corynebacterium sp. (Pot N2) isolated from rice and potato phyllosphere, respectively, were tested on wheat seedlings in vitro, for their efficiencies to increase dry weight and total nitrogen content of the plant, to establish their utility as potential biofertilizers. An average increase in dry weight nearly by 35-50% and total nitrogen content by 56-52% was obtained which was near to that available by nitrogenous chemical treatment. A comparatively better result was obtained by REN2 than Pot N2.

Azotobacter↗
PubMed1995

Tear glucose estimation--an alternative to blood glucose estimation.

Dextrostix, being very sensitive to measure glucose level by glucose oxidase method, was chosen to measure tear glucose level to evaluate the relationship of tear glucose to blood glucose level in 94 cases. It was found that in our population the measurement of tear glucose has definite value in interpretation of glucose status of individual. So, it was suggested to use this simple method of detection of tear glucose to interpret hyperglycaemic state of the patients. The present study was undertaken (1) to sort out a definite relationship between tear and plasma glucose concentration and (2) to devise a rapid method for detection of tear glucose level semiquantitatively with glucose oxidase impregnated strips and to evaluate its role as indicator of plasma glucose level.

Blood Glucose↗
PubMed1994

A case-control study of reproductive risk factors associated with cervical cancer.

Using the logistic-regression technique, a hospital-based case-control study of 177 married women with invasive squamous-cell cervical cancer and 149 hospital-visiting controls enabled evaluation of selected reproductive factors as risks. Early age at marriage was found to be the single best predictor of the disease status. However, those who married late but gave birth to a large number of children were generally found to be suffering from cervical cancer. The results support the hypothesis that it is not so much parity per se that enhances the risk, but the rapidity of multiple pregnancies that matters. Logistic analysis also revealed the independent influence of birth interval on the risk of cervical cancer. These findings warrant serious consideration in future studies, given the obvious implications for prevention. Other implications for the prevention of cervical cancer are briefly discussed.

Adult↗