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Biomedical subjects

P Mukhopadhyay

Publications and source records attributed to P Mukhopadhyay.

At least 19 recordsLinked to original sources
PubMed2006

Molecular fingerprinting of BMP2- and BMP4-treated embryonic maxillary mesenchymal cells.

OBJECTIVE: To determine the differences in gene expression between control-, bone morphogenetic protein (BMP)2- and BMP4-treated murine embryonic maxillary mesenchymal (MEMM) cells. DESIGN: Transcript profiles of BMP2-, BMP4- and vehicle-treated MEMM cells were compared utilizing the murine high-density GeneChip arrays from Affymetrix. The raw chip data (probe intensities) were pre-processed using robust multichip averaging with GC-content background correction and further normalized with GeneSpring v7.2 software. Cluster analysis of the microarray data was performed with the GeneSpring software. Changes in the gene expression were verified by TaqMan quantitative real-time PCR. RESULTS: Expression of approximately 50% of the 45 101 genes and expressed sequence tags examined in this study were detected in BMP2-, BMP4- and vehicle-treated MEMM cells and that of several hundred genes was significantly altered (up or downregulated) in these cells in response to BMP2 and BMP4. Expression profiles of each of the 26 mRNAs tested by TaqMan quantitative real-time PCR were found to be consistent with the microarray data. Genes whose expression was modulated following BMP2 or BMP4 treatment, could be broadly classified based on the functions of the encoded proteins such as the growth factors and signaling molecules, transcription factors, and proteins involved in epithelial-mesenchymal interactions, extracellular matrix synthesis, cell adhesion, proliferation, differentiation, and apoptosis. CONCLUSION: Utilization of the Affymetrix GeneChip microarray technology has enabled us to delineate a detailed transcriptional map of BMP2 and BMP4 responsiveness in embryonic maxillary mesenchymal cells and offers revealing insights into crucial molecular regulatory mechanisms employed by these two growth factors in orchestrating embryonic orofacial cellular responses.

Animals↗
PubMed2004

Trastuzumab and docetaxel for metastatic breast cancer: an experience from a cancer centre in India.

AIMS: To study the toxicity profile and effectiveness of combination of trastuzumab and docetaxel in women with metastatic breast cancer showing HER-2 overexpression (IHC 3+). MATERIALS AND METHODS: Sixteen women with metastatic breast cancer were treated with trastuzumab (2 mg/kg every week) and docetaxel (100 mg/m2) as first-line therapy. A loading dose of 4 mg/kg trastuzumab was given on week 1. We planned to give a minimum of six cycles of docetaxel chemotherapy. RESULTS: A total of 89 cycles of docetaxel chemotherapy was given (median five cycles per patient). Median number of cycles of trastuzumab was 44 with a range of 20-71. Of the 16 patients, seven (44%) had complete response (CR), whereas five patients (31%) had partial response (PR). The overall response rate (CR+PR) was 75%. Two patients died of progressive disease, and the other two died at home, for which the cause of death could not be known. No anaphylaxis, cardio-toxicity or febrile neutropenia was observed in any patient. Overall, the toxicity was within tolerable limits. CONCLUSION: The combination of trastuzumab and docetaxel in women with metastatic breast cancer showing HER-2 overexpression (IHC 3+) is a safe and effective regimen. However, further randomised trials are needed to establish its role in metastatic breast cancer.

Adult↗
PubMed2003

Molecular fingerprinting of TGFbeta-treated embryonic maxillary mesenchymal cells.

The transforming growth factor-beta (TGF(beta)) family represents a class of signaling molecules that plays a central role in normal embryonic development, specifically in development of the craniofacial region. Members of this family are vital to development of the secondary palate where they regulate maxillary and palate mesenchymal cell proliferation and extracellular matrix synthesis. The function of this growth factor family is particularly critical in that perturbation of either process results in a cleft of the palate. While the cellular and phenotypic effects of TGF(beta) on embryonic craniofacial tissue have been extensively cataloged, the specific genes that function as downstream mediators of TGF(beta) in maxillary/palatal development are poorly defined. Gene expression arrays offer the ability to conduct a rapid, simultaneous assessment of hundreds to thousands of differentially expressed genes in a single study. Inasmuch as the downstream sequelae of TGF(beta) action are only partially defined, a complementary DNA (cDNA) expression array technology (Clontech's Atlas Mouse cDNA Expression Arrays), was utilized to delineate a profile of differentially expressed genes from TGF(beta)-treated primary cultures of murine embryonic maxillary mesenchymal cells. Hybridization of a membrane-based cDNA array (1178 genes) was performed with 32P-labeled cDNA probes synthesized from RNA isolated from either TGF(beta)-treated or vehicle-treated embryonic maxillary mesenchymal cells. Resultant phosphorimages were subject to AtlasImage analysis in order to determine differences in gene expression between control and TGF(beta)-treated maxillary mesenchymal cells. Of the 1178 arrayed genes, 552 (47%) demonstrated detectable levels of expression. Steady state levels of 22 genes were up-regulated, while those of 8 other genes were down-regulated, by a factor of twofold or greater in response to TGF(beta). Affected genes could be grouped into three general functional categories: transcription factors and general DNA-binding proteins; growth factors/signaling molecules; and extracellular matrix and related proteins. The extent of hybridization of each gene was evaluated by comparison with the abundant, constitutively expressed mRNAs: ubiquitin, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), ornithine decarboxylase (ODC), cytoplasmic beta-actin and 40S ribosomal protein. No detectable changes were observed in the expression levels of these genes in-response to TGF(beta) treatment. Gene expression profiling results were verified by Real-Time quantitative polymerase chain reaction. Utilization of cDNA microarray technology has enabled us to delineate a preliminary transcriptional map of TGF(beta) responsiveness in embryonic maxillary mesenchymal cells. The profile of differentially expressed genes offers revealing insights into potential molecular regulatory mechanisms employed by TGF(beta) in orchestrating craniofacial ontogeny.

Animals↗
PubMed2003

A comparative study of classical vs. desmoplastic medulloblastomas.

Classical and desmoplastic medulloblastomas (MBs) have been suspected to be biologically different, though comparative studies on markers of biological aggressiveness in these two variants are sparse in the literature. 87 classical and 43 desmoplastic variants of MB were studied with respect to clinical and histological characteristics, MIB-1 labeling index (MIB-1 LI), apoptotic index (AI), ratio of AI to MIB-1 LI, expression of p53 and Bcl-2 protein and 3-year progression-free survival. The only differences documented between the variants were with regard to age distribution and location. Thus, classical histology cases occurred predominantly in children and 80% were midline in location. In contrast, lateral location was seen more frequently with tumors of desmoplastic histology, which occurred in an almost equal distribution between children (56%) and adults (44%). No difference was noted between the variants with regard to proliferation index, apoptotic index, their ratio on or their molecular controls (p53 and Bcl-2). This was reflected in the clinical outcome wherein no significant difference was observed in the 3-year progression-free survival between the variants. It is concluded that the two histological variants of medulloblastoma are not different with regard to biological parameters of aggressiveness. The growth rate and clinical outcome in medulloblastomas have no correlation with the histological variant.

Adolescent↗
PubMed2002

A melanotic desmoplastic medulloblastoma: report of a rare case and review of the literature.

A 28-year-old man had a desmoplastic medulloblastoma in the vermis and left cerebellum. This tumor was composed of nodular, reticulin-free zones (pale islands) surrounded by densely packed, highly proliferative cells that produced a dense intercellular reticulin network. Some of the cells were heavily pigmented, and this pigment proved to be melanin. Adult age, desmoplastic nature, and melanin pigmentation are some of the rare features of this tumor that need documentation. Further, this pigment was in the primitive cells, unlike in the published cases, in which it was present in the tubular or tubulopapillary component. To the best of our knowledge, this is the first published case of desmoplastic pigmented medulloblastoma, and the patient is the oldest reported to have this tumor.

Adult↗
PubMed2002

Lipomedulloblastoma in a child: a controversial entity.

Lipomedulloblastoma is regarded as a distinct entity that occurs exclusively in adults and has a low proliferative potential and a favorable outcome. We describe a rare case of lipomedulloblastoma in a 6-year-old female child showing a high labeling index that needs documentation. The various hypotheses of adiposal change are discussed.

Adipose Tissue↗
PubMed2001

Evolution of induced axial magnetization in a two-component magnetized plasma.

In this paper, the evolution of the induced axial magnetization due to the propagation of an electromagnetic (em) wave along the static background magnetic field in a two-component plasma has been investigated using the Block equation. The evolution process induces a strong magnetic anisotropy in the plasma medium, depending nonlinearly on the incident wave amplitude. This induced magnetic anisotropy can modify the dispersion relation of the incident em wave, which has been obtained in this paper. In the low frequency Alfven wave limit, this dispersion relation shows that the resulting phase velocity of the incident wave depends on the square of the incident wave amplitude and on the static background magnetic field of plasma. The analytical results are in well agreement with the numerically estimated values in solar corona and sunspots.

Journal Article↗
PubMed2001

Structural basis of the redox switch in the OxyR transcription factor.

The Escherichia coli OxyR transcription factor senses H2O2 and is activated through the formation of an intramolecular disulfide bond. Here we present the crystal structures of the regulatory domain of OxyR in its reduced and oxidized forms, determined at 2.7 A and 2.3 A resolutions, respectively. In the reduced form, the two redox-active cysteines are separated by approximately 17 A. Disulfide bond formation in the oxidized form results in a significant structural change in the regulatory domain. The structural remodeling, which leads to different oligomeric associations, accounts for the redox-dependent switch in OxyR and provides a novel example of protein regulation by "fold editing" through a reversible disulfide bond formation within a folded domain.

Bacterial Proteins↗
PubMed2001

Primary spinal epidural extraosseous Ewing's sarcoma: report of five cases and literature review.

Ewing's sarcoma is the most common malignant bone tumour occurring in children and adolescents and exists in two different clinicopathological entities: osseous Ewing's sarcoma (OES) and extraosseous Ewing's sarcoma (EES). Five cases of primary epidural EES are described, which presented with non-specific symptoms leading to a long diagnostic delay. The median age at diagnosis was 22 years (range 13-36 years). The median diagnostic delay was 3 months. All patients had one or more neurological deficits. All underwent surgical exploration with a laminectomy and partial resection followed by adjuvant radiotherapy to a dose of 46-50 Gy and chemotherapy with VAC (vincristine, adriamycin and cyclophosphamide) alternating with ICE (ifosphamide, cisplatin and etoposide) for at least six cycles. The mean follow-up period is 21.2 months (range 11-32 months). Four of the five patients achieved a complete remission and are disease free at the time of writing this report. Two patients have a residual neurological deficit--both having presented with long history of neurological deficit. Primary spinal epidural EES should be suspected whenever young patients present with back pain and/or radicular pain, have abnormal neurology and an extradural mass is demonstrated on MRI. Surgical excision followed by adjuvant radiotherapy (50 Gy) and combination chemotherapy (VAC alternating with ICE) achieved local and systemic control in these patients. A greater number of patients and longer follow up are required to evolve a generally accepted treatment policy for this aggressive but potentially curable malignancy.

Adolescent↗
PubMed2001

Localization of EP(1) and FP receptors in human ocular tissues by in situ hybridization.

PURPOSE: To examine the expression and localization of EP(1) and FP receptor mRNAs in normal human ocular tissues by in situ hybridization. METHODS: Digoxigenin-labeled human EP(1) and FP receptor antisense and sense riboprobes were used for in situ hybridization on paraffin sections of normal human eye tissue. RESULTS: In situ hybridization revealed the presence of high levels of both EP(1) and FP receptor mRNA transcripts in the blood vessels of iris, ciliary body, and choroid. Both the endothelial and smooth muscle cells of blood vessels demonstrated intense hybridization signals corresponding to EP(1) receptor mRNA transcript. EP(1) receptor hybridization signals were present in all the muscle fibers of the ciliary body. In the retina, hybridization signals for EP(1) receptors were observed in photoreceptors and both nuclear layers and in ganglion cells. The hybridization signals corresponding to FP receptor transcript were similar to those of EP(1) receptors in the iris tissues. In the ciliary muscle, FP receptor mRNA transcript was predominantly present in the circular muscle and in the collagenous connective tissues; no hybridization signal for this receptor was observed in the retina. CONCLUSIONS: The wide distribution of EP(1) and FP receptor mRNAs in human ocular tissues appears to be localized in the functional sites of the respective receptor agonists. Selective localization of FP receptor mRNA in the circular muscles and collagenous connective tissues of the ciliary body suggests their involvement in the increased uveoscleral outflow of aqueous humor by PGF(2alpha).

Blotting, Northern↗
PubMed2001

Diabetic care in general practice--a survey.

Prevalence of diabetes mainly type-2 is growing astronomically. Multiple insulin delivery systems are on trial from jet to pump, nasal spray, oral insulin and rectal suppository with success and failures to have insulin pen--which is growing popularly. Two studies have shown that non-insulin dependent diabetes mellitus patients needed insulin for good glycaemic control. To see the knowledge of these developments among general practitioners, a set of questions with possible answers were distributed among 48 doctors selected from different areas. Twelve doctors showed no interest. Majority (65%) answered they see less than 5 new diabetics a week, whereas 35% see more than 5 a week. Most clinicians (58%) rarely use insulin. A sizeable section (46%) has not heard of any other insulin administration advices other than syringe and needle. So in the context of the questionnaire with answers, it can safely be presumed that concept of diabetes care needs a continuous update.

Diabetes Mellitus↗
PubMed1999

Use of recursive partitioning in the sequential screening of G-protein-coupled receptors.

High-throughput screening (HTS) is changing as more compounds and better assay techniques become available. HTS is also generating a large amount of data. There is a need to rationalize the HTS process, because, in some cases, the screening of all available compounds is not economically feasible. In addition to the selection of promising compounds, there is a need to learn from the data that we collect. In this paper, we use a data-mining method, recursive partitioning, to help uncover and understand structure-activity relations and to help biology and chemistry experts make better decisions on which compounds to screen next and better characterize. The sequential-screening process is presented and the results of applying that process to 14 G-protein-coupled receptor assays are reported.

Animals↗
PubMed1999

Bovine iris-sphincter muscle lacks FP receptor binding sites.

PURPOSE: To determine the affinity, density, and specificity of the binding sites of tritium-labeled prostaglandin F2alpha in membrane preparations of bovine iris-sphincter muscle and corpus luteum. METHODS: Membrane preparations were incubated with 0.312-40.0 nM 3H-prostaglandin F2alpha in saturation experiments, or 8 nM 3H-prostaglandin F2alpha in competition studies, in the presence or absence of varying concentrations of unlabeled prostaglandin F2alpha or other prostaglandin receptor agonists. The affinity (Kd) and the density of the binding sites (Bmax) of 3H-prostaglandin F2alpha in the bovine iris-sphincter muscle were determined by Scatchard analysis. Reverse transcription polymerase chain reaction was performed with bovine iris-sphincter muscle and corpus luteum total RNA and the PCR products were hybridized with specific 32P-labeled probe for further confirmation of FP receptor expression. RESULTS: Specific binding sites of 3H-prostaglandin F2alpha in the membranes of bovine iris-sphincter muscle are saturable with an affinity of 9.5 nM and a density of 596 fmoles/mg of protein. Prostaglandin E2, 17-phenyl trinor prostaglandin E2, and GR63799 (EP, EP1, and EP3 receptor agonists, respectively) inhibited 3H-prostaglandin F2alpha binding with an IC50 of 0.0048 microM, 0.0038 microM, and 0.044 microM, respectively. Fluprostenol, a specific FP receptor agonist did not inhibit 3H-prostaglandin F2alpha binding. In contrast, prostaglandin F2alpha and fluprostenol effectively inhibited 3H-prostaglandin F2alpha binding in the bovine corpus luteum with an IC50 of 0.031 microM and 0.037 microM, respectively. CONCLUSIONS: Our results demonstrate that in the bovine iris-sphincter muscle, FP receptors are not expressed and 3H-prostaglandin F2alpha binds to EP1 and EP3 receptor sites. RT-PCR results demonstrated that FP receptor mRNA, which is present in bovine corpus luteum, is probably absent in iris-sphincter muscle.

Animals↗
PubMed1999

Expression of prostaglandin receptors EP4 and FP in human lens epithelial cells.

PURPOSE: To examine the expression of prostaglandin (PG) receptors EP2, EP4, and FP in a human lens epithelial cell line (HLE-B3) at molecular and pharmacologic levels. METHODS: Reverse transcription-polymerase chain reactions (RT-PCR) were performed with total RNA preparations from HLE-B3 cells using sense and antisense primers for each of the three prostaglandin receptors. The PCR products were hybridized with specific 32P-labeled probes and, for further confirmation, digested with appropriate restriction enzymes. At the pharmacologic level, the expression of EP4 receptors was determined by measuring intracellular cyclic adenosine monophosphate (cAMP) formation in response to PGE2 (EP1, EP2, EP3, and EP4 agonist) and the EP4 receptor-selective antagonist AH23848. The expression of FP receptors in HLE-B3 cells was explored by measuring intracellular [Ca2+]i mobilization. RESULTS: RT-PCR generated DNA products of predicted sizes corresponding to the EP2, EP4, and FP receptors. Hybridization of the PCR products with specific 32P-labeled probes and restriction digestion of the PCR products further confirmed that they were generated from the respective EP2, EP4, and FP mRNAs. The EP receptor agonist PGE2 significantly increased the cAMP level in HLE-B3 cells. The formation of cAMP by PGE2 was concentration-dependently inhibited by the EP4 receptor-selective antagonist AH23848. Stimulation of HLE-B3 cells by the FP receptor agonist fluprostenol increased [Ca2+]i in a time-dependent manner. CONCLUSIONS: The results of the molecular biologic and pharmacologic experiments showed conclusively the presence of EP4 and FP receptor messenger RNAs and proteins, respectively, in HLE-B3 cells.

Actins↗
PubMed1998

Protein engineering of BamHI restriction endonuclease: replacement of Cys54 by Ala enhances catalytic activity.

Chemical modification studies of BamHI endonuclease indicated the importance of the cysteine residue in catalysis [Nath, K. (1981) Arch. Biochem. Biophys, 212, 611-617]. Of the three cysteine residues at positions 34, 54 and 64 in the BamHI endonuclease Cys54 and Cys64 are at the DNA-protein interface. The co-crystal structure of the BamHI-DNA complex, however, does not indicate any role of cysteines either in binding or catalysis. In the context of strong biochemical evidence, Cys54 in BamHI was changed to Ala54 to investigate its role in catalysis. The mutation was carried out by PCR overlap extension, the mutant gene was cloned and characterized by sequencing. The mutant BamHI was expressed and purified to homogeneity and the kinetic parameters (K(M) and kcat) of the wild type and the C54A mutant were determined. The mutation results in up to approximately 40% enhancement of kcat and some increase in K(M). These in vitro results were also supported by in vivo SOS induction assays: the C54A mutant gene under the T7 promoter caused complete lysis in JH139 in absence of T7 RNA polymerase whereas the wild-type gene gave deep blue colonies under the same conditions. The results suggest no direct role of Cys54 in catalysis, but it can influence the catalytic activity through Val57 backbone contact seen in the co-crystal structure.

Alanine↗
PubMed1997

Elution Behavior of Chemically Different Probes on the Evaluation of Surface Properties of Cellulose by Inverse Gas Chromatography

The inverse gas chromatography (IGC) technique has been employed to examine adsorption behavior of cellulose surfaces from elution characteristics of chemically different adsorbates. The neutral probes were eluted completely during IGC measurements while acidic, amphoteric, and basic probe molecules were eluted incompletely. In this work, complete elution is defined by the flat postpeak FID signal within the noise limits of the detector. An understanding of incomplete elution is thereby reached by introducing a precisely controlled, very small quantity of individual probes into the column. A strong correlation is found between elution efficiency of vapors and their enthalpies of acid-base interactions. Delayed elution of acid-base vapors is interpreted as being due to nonequilibrium sorption process, and calculations have shown that diffusion into the bulk is unlikely under the measurement conditions. The chromatographic process is simulated and it is found that the contribution of nonequilibrium adsorption to the retention is responsible for observed peak tailing and thereby delayed elution of acid-base probes. Results of the study indicate that characterization of acid-base (electron acceptor-donor) type of stationary phase material surfaces by IGC needs careful attention and is an area for future work. Copyright 1997 Academic Press. Copyright 1997Academic Press

Journal Article↗