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Biomedical subjects

P Chatterjee

Publications and source records attributed to P Chatterjee.

At least 19 recordsLinked to original sources
PubMed2004

Validity of Queen's College step test for use with young Indian men.

OBJECTIVES: To assess the suitability of the Queen's College step test (QCT) to predict maximum oxygen uptake in Indian men. METHODS: Thirty sedentary male university students from West Bengal, India, with the same socioeconomic background and mean (SD) age, height, and weight of 22.6 (0.2) years, 166.4 (0.5) cm, and 53.8 (0.2) kg, respectively, were randomly sampled from University of Calcutta. VO2max of each participant was determined by direct procedure involving incremental bicycle exercise and also by applying indirect QCT method with a gap of 4 days between the tests. RESULTS: The difference between the mean (SD) VO2max values directly measured (VO2max = 39.8 (1.03) ml/min/kg body mass) and indirectly predicted (PVO2max = 39.3 (1.07) ml/min/kg body mass) was statistically insignificant (p>0.10). PVO2max and VO2max values expressed as ml/min/kg body mass corroborated with previous studies in the same laboratory involving the same population, and also exhibited significant statistical correlation (r = 0.95, p<0.001) between them. CONCLUSION: The results suggest that QCT can be applied in the studied population to produce a good estimation of maximum oxygen uptake, especially in the field where large numbers of participants are to be evaluated without a well equipped laboratory.

Adult↗
PubMed2000

Microbial transformations of the antimelanoma agent betulinic acid.

Microbial transformation studies of the antimelanoma agent betulinic acid (1) were conducted. Screening experiments showed a number of microorganisms capable of biotransforming 1. Three of these cultures, Bacillus megaterium ATCC 14581, Cunninghamella elegans ATCC 9244, and Mucor mucedo UI-4605, were selected for preparative scale transformation. Bioconversion of 1 with resting-cell suspensions of phenobarbital-induced B. megaterium ATCC 14581 resulted in the production of the known betulonic acid (2) and two new metabolites: 3beta,7beta-dihydroxy-lup-20(29)-en-28-oic acid (3) and 3beta,6alpha, 7beta-trihydroxy-lup-20(29)-en-28-oic acid (4). Biotransformation of 1 with growing cultures of C. elegans ATCC 9244 produced one new metabolite characterized as 1beta,3beta, 7beta-trihydroxy-lup-20(29)-en-28-oic acid (5). Incubation of 1 with growing cultures of M. mucedo UI-4605 afforded metabolite 3. Structure elucidation of all metabolites was based on NMR and HRMS analyses. In addition, the antimelanoma activity of metabolites 2-5 was evaluated against two human melanoma cell lines, Mel-1 (lymph node) and Mel-2 (pleural fluid).

Antineoplastic Agents↗
PubMed2000

Biotransformation of the antimelanoma agent betulinic acid by Bacillus megaterium ATCC 13368.

Microbial transformation of the antimelanoma agent betulinic acid was studied. The main objective of this study was to utilize microorganisms as in vitro models to predict and prepare potential mammalian metabolites of this compound. Preparative-scale biotransformation with resting-cell suspensions of Bacillus megaterium ATCC 13368 resulted in the production of four metabolites, which were identified as 3-oxo-lup-20(29)-en-28-oic acid, 3-oxo-11alpha-hydroxy-lup-20(29)-en-28-oic acid, 1beta-hydroxy-3-oxo-lup-20(29)-en-28-oic acid, and 3beta,7beta, 15alpha-trihydroxy-lup-20(29)-en-28-oic acid based on nuclear magnetic resonance and high-resolution mass spectral analyses. In addition, the antimelanoma activities of these metabolites were evaluated with two human melanoma cell lines, Mel-1 (lymph node) and Mel-2 (pleural fluid).

Antineoplastic Agents, Phytogenic↗
PubMed2000

Enhanced H(2)O(2)-induced cytotoxicity in "epithelioid" smooth muscle cells: implications for neointimal regression.

Vascular smooth muscle cells (SMCs) are phenotypically diverse. Although most medial SMCs can be classified as "fusiform," others are of the "epithelioid" phenotype. Proliferation and apoptosis of epithelioid SMCs may contribute importantly to neointimal formation and regression, respectively. Because reactive oxygen species (ROS) are increased in vascular injury and can induce apoptosis of SMCs, we compared the effects of ROS on epithelioid and fusiform SMCs. Epithelioid and fusiform SMC lines were clonally isolated from rat aortic media and studied under similar conditions and passage numbers. H(2)O(2) produced dose- and time-dependent cytotoxicity that was enhanced in epithelioid compared with fusiform cells. After 24-hour exposure to 50 micromol/L H(2)O(2), epithelioid cell numbers were reduced by 34+/-5% versus a 3+/-5% (P<0.05) reduction in fusiform cell numbers. Similar results were obtained whether H(2)O(2) was administered to growth-arrested or growing cells or when epithelioid and fusiform cells were exposed to extracellular O(2)(.-). To investigate whether apoptosis contributed to enhanced ROS-induced cytotoxicity in epithelioid SMCs, terminal deoxyribonucleotidyl transferase (TDT)-mediated dUTP-digoxigenin nick-end labeling (TUNEL) staining was performed. The incidence of TUNEL positivity was 5-fold increased in epithelioid versus fusiform SMCs after treatment with 50 micromol/L H(2)O(2) (19+/-1% epithelioid versus 5+/-1% fusiform, P<0.05). Enhanced H(2)O(2)-induced apoptosis in epithelioid SMCs was confirmed by DNA laddering. Furthermore, when balloon-injured aortas were exposed to H(2)O(2) ex vivo, enhanced apoptosis was observed in neointimal compared with medial SMCs. These results suggest that epithelioid SMCs exhibit enhanced sensitivity to ROS-induced apoptosis, which may play an important role in neointimal regression.

Animals↗
PubMed1999

Overexpression of human catalase inhibits proliferation and promotes apoptosis in vascular smooth muscle cells.

The role of reactive oxygen species, such as superoxide anions (O(2). (-)) and hydrogen peroxide (H(2)O(2)), in modulating vascular smooth muscle cell proliferation and viability is controversial. To investigate the role of endogenously produced H(2)O(2), rat aortic smooth muscle cells were infected with adenoviral vectors containing cDNA for human catalase (AdCat) or a control gene, beta-galactosidase (AdLacZ). Infection with AdCat resulted in dose-dependent increases in intracellular catalase protein, which was predominantly localized to peroxisomes. After infection with 100 multiplicity of infection (MOI) of AdCat, cellular catalase activity was increased by 50- to 100-fold, and intracellular H(2)O(2) concentration was reduced, as compared with control. Infection with AdCat reduced [(3)H]thymidine uptake, an index of DNA synthesis, in cells maintained in medium supplemented with 2% serum (0.37+/-0.09 disintegrations per minute per cell [AdLacZ] versus 0.22+/-0.08 disintegrations per minute per cell [AdCat], P<0.05). Five days after infection with 100 MOI of AdCat, cell numbers were reduced as compared with noninfected or AdLacZ-infected cells (157 780+/-8413 [AdCat], P<0.05 versus 233 700+/-3032 [noninfected] or 222 410+/-5332 [AdLacZ]). Furthermore, the number of apoptotic cells was increased 5-fold after infection with 100 MOI of AdCat as compared with control. Infection with AdCat resulted in induction of cyclooxygenase (COX)-2, and treatment with a COX-2 inhibitor overcame the AdCat-induced reduction in cell numbers. These findings indicate that overexpression of catalase inhibited smooth muscle proliferation while increasing the rate of apoptosis, possibly through a COX-2-dependent mechanism. Our results suggest that endogenously produced H(2)O(2) importantly modulates survival and proliferation of vascular smooth muscle cells.

Animals↗
PubMed1999

Glucosidation of betulinic acid by Cunninghamella species.

Microbial transformation of the antimelanoma agent betulinic acid (1) was studied. Preparative scale biotransformation with resting-cell suspensions of Cunninghamella species NRRL 5695 resulted in the production of a fungal metabolite of 1, which has been characterized as 28-O-beta-D-glucopyranosyl 3beta-hydroxy-lup-20(29)-en-28-oate (2) based on spectral and enzymic data. The in vitro cytotoxicity assay of metabolite 2 revealed no activity against several human melanoma cell lines.

Antineoplastic Agents, Phytogenic↗
PubMed1999

Epoxide hydrolases regulate epoxyeicosatrienoic acid incorporation into coronary endothelial phospholipids.

Cytochrome P-450-derived epoxyeicosatrienoic acids (EETs) are avidly incorporated into and released from endothelial phospholipids, a process that results in potentiation of endothelium-dependent relaxation. EETs are also rapidly converted by epoxide hydrolases to dihydroxyeicosatrienoic acid (DHETs), which are incorporated into phospholipids to a lesser extent than EETs. We hypothesized that epoxide hydrolases functionally regulate EET incorporation into endothelial phospholipids. Porcine coronary artery endothelial cells were treated with an epoxide hydrolase inhibitor, 4-phenylchalcone oxide (4-PCO, 20 micromol/l), before being incubated with (3)H-labeled 14,15-EET (14,15-[(3)H]EET). 4-PCO blocked conversion of 14,15-[(3)H]EET to 14,15-[(3)H]DHET and doubled the amount of radiolabeled products incorporated into cell lipids, with >80% contained in phospholipids. Moreover, pretreatment with 4-PCO before incubation with 14,15-[(3)H]EET enhanced A-23187-induced release of radiolabeled products into the medium. In contrast, 4-PCO did not alter uptake, distribution, or release of [(3)H]arachidonic acid. In porcine coronary arteries, 4-PCO augmented 14,15-EET-induced potentiation of endothelium-dependent relaxation to bradykinin. These data suggest that epoxide hydrolases may play a role in regulating EET incorporation into phospholipids, thereby modulating endothelial function in the coronary vasculature.

8,11,14-Eicosatrienoic Acid↗
PubMed1999

The estimation of the heritability of anthropometric measurements.

The relative contributions of genetic and environmental components in the variability of anthropometric measurements were studied in 54 twin pairs. Thirty pairs of monozygotic (MZ) and 24 pairs of dizygotic (DZ) twins were investigated to estimate the role of genetic, environmental and hereditary factors determining anthropometric measurements comprising body weight, standing height, sitting height, knee height, arm span, chest circumference and biiliac diameter. Within-pair variance for all the measurements were significantly smaller (p < 0.05-0.01) in MZ twins than in DZ twins of both-sex twin group. Within-pair correlations for those measurements were higher (p < 0.01) in both MZ and DZ twins. Correlation values were, apparently, higher more in MZ than in DZ twins. Besides, all the measurements are highly heritable components and heritability estimates ranged 40%-91%. When both MZ and DZ twin pairs of both-sex population were classified, based on age and sex, into different sub-groups interindividual variabilities were altered to a certain degrees. These data state that anthropometric measurements are influenced by genetic factors than environmental factors and besides, age and sex are possibly associated, to some extent, with the genetic influence upon anthropometric measurements.

Adolescent↗
PubMed1998

Expression of abscisic acid-responsive element-binding protein in salt-tolerant indica rice (Oryza sativa L. cv. Pokkali).

As the products of abiotic stress and ABA inducible genes are predicted to play an important role in the mechanism of salt tolerance, the expression of transcription factor that recognizes abscisic acid-responsive element (ABRE) is likely to be regulated when plants are exposed to abiotic stress. Northern analysis of total RNA from control and salt-treated 10-day-old Pokkali (salt tolerant) rice plants was performed to find out the level of transcripts homologous to wheat cDNA (GC19) for EmBP-1 (bZIP class factor), a transcription factor that recognizes ABRE. Salinity stress (72 h)-induced accumulation of two transcripts, of 2.0 kb (r2.0) and 1.5 kb (r1.5), in roots was detected. Both transcripts were detectable even after 6 h of salt or abscisic acid treatment, whereas sheath and lamina showed constitutive levels of r1.5 transcript. When 32P-labeled DNA containing ABRE was used in a gel mobility shift assay, a low level of complex formation by binding factor was detected from the nuclear extract of lamina of control rice plants. Quantitative enhancement of complex formation was found with the nuclear extract prepared from the lamina of plants treated with 200 mM NaCl for 26 h over control nuclear extract, suggesting a step of regulation of expression of ABRE-binding protein in response to salinity stress. South-western blot analysis of equal amounts of nuclear proteins of lamina showed binding of 32P-labeled ABRE-DNA with two polypeptides (22-28 kDa) present at constitutive levels in control or NaCl-treated plants. Preincubation of the laminar nuclear extract of control plants, with spermidine or proline at 5 mM concentration showed quantitative enhancement of ABRE binding activity. Kinetics of spermidine stimulation showed gradual increase of complex formation from 5 mM concentration. Similarly, addition of GTP to the control nuclear extract also showed quantitative enhancement of complex formation and heparin was found to inhibit GTP activated complex formation by about 25%. Results may suggest the presence of ABRE binding protein in presynthesized and inactive form in control plants and GTP mediated activation is probably one of the way to regulate the expression of ABRE-binding factor.

Abscisic Acid↗
PubMed1997

Isolation and characterization of primordial follicles from fresh and cryopreserved human ovarian tissue.

OBJECTIVE: To develop an efficient isolation technique for human primordial follicles. DESIGN: Prospective, experimental study of ovarian biopsies collected from healthy women undergoing elective cesarean section. Ovarian blocks either were fixed for histology and follicle counting or partially disaggregated with type 1A collagenase before or after cryopreservation. After partial disaggregation, follicles were isolated by microdissection. SETTING: Leeds General Infirmary. MAIN OUTCOME MEASURE(S): Follicle viability was assessed with live-dead stains using 5-(and 6-) carboxyfluorescein diacetate, succinimidyl ester and propidium iodide, respectively, and using electron microscopy. The numbers recovered were expressed as a percentage of the numbers of primordial follicles in comparable blocks of tissue and the viability of the whole follicle and oocyte were scored separately. RESULT(S): On average, 18.0 +/- 3.8 and 15.9 +/- 2.2 (mean +/- SEM) follicles per block were recovered from fresh and cryopreserved ovarian tissue, respectively, corresponding to recovery rates of 57.9% +/- 8.8% and 56.2% +/- 16.7%. In the fresh group, the percent viability of whole follicles and oocytes were 71.6% +/- 2.4% and 91.3% +/- 2% compared with 71.5% +/- 4.7% and 95% +/- 4.3% in the frozen-thawed group. Electron microscopy confirmed that the majority of the cells lacked ultrastructural signs of damage after isolation and cryopreservation. CONCLUSION(S): Primordial follicles can be isolated from fresh and cryopreserved human ovarian tissue with similar high efficiency and viability rates.

Adult↗
PubMed1997

Potentiation of endothelium-dependent relaxation by epoxyeicosatrienoic acids.

Epoxyeicosatrienoic acids (EETs) are potent endothelium-derived vasodilators formed from cytochrome P-450 metabolism of arachidonic acid. EETs and their diol products (DHETs) are also avidly taken up by endothelial cells and incorporated into phospholipids that participate in signal transduction. To investigate the possible functional significance of EET and DHET incorporation into cell lipids, we examined the capacity of EETs and DHETs to relax porcine coronary arterial rings and determined responses to bradykinin (which potently activates endothelial phospholipases) before and after incubating the rings with these eicosanoids. 14,15-EET and 11,12-EET (5 mumol/L) produced 75 +/- 9% and 52 +/- 4% relaxation, respectively, of U46619-contracted rings, whereas 8,9-EET and 5,6-EET did not produce significant relaxation. The corresponding DHET regioisomers produced comparable relaxation responses. Preincubation with 14,15-EET, 11,12-EET, 14,15-DHET, and 11,12-DHET augmented the magnitude and duration of bradykinin-induced relaxation, whereas endothelium-independent relaxations to aprikalim and sodium nitroprusside were not potentiated. Pretreatment with 2 mumol/L triacsin C (an inhibitor of acyl coenzyme A synthases) inhibited [3H]14,15-EET incorporation into endothelial phospholipids and blocked 11,12-EET- and 14,15-DHET-induced potentiation of relaxation to bradykinin. Exposure of [3H]14,15-EET-labeled endothelial cells to the Ca2+ ionophore A23187 (2 mumol/L) resulted in a 4-fold increased release of EET and DHET into the medium. We conclude that incorporation of EETs and DHETs into cell lipids results in potentiation of bradykinin-induced relaxation in porcine coronary arteries, providing the first evidence that incorporated EETs and DHETs are capable of modulating vascular function.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1995

Return of fertility following discontinuation of Norplant-II subdermal implants. ICMR Task Force on Hormonal Contraception.

A total of 627 women who had discontinued the use of the Norplant-II implants for various reasons and were exposed to the risk of pregnancy were followed-up for two years for return of fertility. The cumulative conception rates in women who had discontinued due to planning pregnancy were 80.3 per 100 women at one year and 88.3 per 100 women at two years. The majority of women who did conceive (90 percent), had full-term normal live births; about 4 percent of women had spontaneous abortions, the remaining 6 percent decided on elective termination of pregnancy (ETP). The cumulative conception rates in women who discontinued due to bleeding irregularities and 'other reasons' were 64.5 and 55.8 per 100 women at one year and 77.9 and 75.1 per 100 women at two years, respectively. These rates were significantly lower as compared to those observed in women who discontinued due to planning pregnancy. A large proportion, about 40 percent, of women who conceived after discontinuation of the method due to bleeding irregularities and "other reasons," opted for ETP indicating that many women in these two groups did not desire another child and that such women need to be counselled for adopting another method of contraception. The spontaneous abortion rates observed in ex-users of Norplant-II implants (1.7 to 4.4% pregnancies) were comparable to the spontaneous abortion rates prior to Norplant-II implant use (3.6% pregnancies) indicating that ex-users of Norplant-II implants were not at a higher risk of spontaneous abortion.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Nitric oxide production by human proximal tubular cells: a novel immunomodulatory mechanism?

It is believed that human proximal tubular cells may possess immunological function and play an important role in a variety of renal disease states such as interstitial nephritis, allograft rejection and drug induced nephrotoxicity. The role of cytokines and nitric oxide in the human forms of these disease states is not clear. In this study we examined the effect of stimulation with the cytokines IL-1 beta. TNF-alpha and IFN-gamma, individually and in combination, upon primary cultures of human proximal tubular cells. Nitric oxide production increased significantly within 24 hours following cytokine stimulation. This response was inhibited, in a dose dependent manner, by L-NMMA. PCR amplification of mRNA extracted from control and cytokine stimulated human proximal tubular cells revealed a NOS product with a > 97% homology with human hepatocyte inducible nitric oxide synthase. The results of this study clearly show that human proximal tubular cells, in primary culture, are capable of producing nitric oxide in response to an immune challenge secondary to the induction of nitric oxide synthase.

Amino Acid Oxidoreductases↗
PubMed1994

Production of linear polymers of HIV gp120-binding domains.

It has been demonstrated previously that molecular decoys of the acetylcholine receptor have therapeutic efficacy as antitoxins [Gershoni, J. and Aronheim, A. (1988) Proc. Natl Acad. Sci. USA, 85, 4087-4089], but surely a most challenging goal is to apply this approach towards the development of antiviral drugs. As viruses present multiple copies of their envelope proteins, it was proposed that polyvalent decoys could be advantageous. Here we report the design and expression of recombinant linear polymers of the HIV gp120-binding domains which are situated within the T-cell membrane protein CD4. Whereas the production of linear concatemers of CD4 variable domains is feasible, a number of conformational constraints must be considered when designing a polymeric molecule which retains biological function. Most significant is the contribution of domains flanking the binding site that apparently enable correct folding of the latter.

Antiviral Agents↗
PubMed1994

Ephedrine remains the vasopressor of choice for treatment of hypotension during ritodrine infusion and epidural anesthesia.

BACKGROUND: Historically, ephedrine has been the vasopressor of choice for treatment of most cases of hypotension in obstetric patients. However, the choice of vasopressor in the parturient receiving a beta-adrenergic agent for tocolysis has not been evaluated extensively. The current study evaluated whether ephedrine or phenylephrine better restores uterine blood flow and fetal oxygenation during ritodrine infusion and epidural anesthesia-induced hypotension in gravid ewes. METHODS: Fourteen chronically instrumented gravid ewes between 0.8 and 0.9 timed gestational age were used. On separate days, each animal underwent the experimental protocol with one of three agents: ephedrine, phenylephrine, and normal saline-control. The experimental protocol was as follows: (1) at time zero, intravenous infusion of ritodrine was begun; (2) at 120 min, 2% lidocaine was given epidurally to achieve a sensory level of at least T6; and (3) at 135 min, an intravenous bolus of either ephedrine, phenylephrine, or normal saline-control was given, followed by a continuous intravenous infusion of the same agent for 30 min. In the ephedrine and phenylephrine experiments, the rate of infusion was adjusted to maintain maternal mean arterial pressure close to baseline. RESULTS: Ritodrine infusion alone significantly increased maternal heart rate and cardiac output in all three groups. Epidural anesthesia during ritodrine infusion significantly decreased maternal mean arterial pressure, heart rate, cardiac output, uterine blood flow, and fetal arterial oxygen tension for each of the three groups. Both ephedrine and phenylephrine restored maternal mean arterial pressure to baseline, as designed. Ephedrine significantly increased uterine blood flow and fetal arterial oxygen tension when compared with normal saline--control, but phenylephrine did not. Phenylephrine significantly increased uterine vascular resistance when compared with normal saline--control, but ephedrine did not. CONCLUSIONS: Although ephedrine and phenylephrine provided similar restoration of maternal mean arterial pressure, ephedrine was superior to phenylephrine in restoring uterine blood flow during ritodrine infusion and epidural anesthesia-induced hypotension in gravid ewes. Also, ephedrine, but not phenylephrine, significantly improved fetal oxygenation, when compared to normal saline--control.

Acid-Base Equilibrium↗