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Biomedical subjects

B Ghosh

Publications and source records attributed to B Ghosh.

At least 37 records · Page 2Linked to original sources
PubMed2003

Cerebrospinal fluid and serum carcinoembryonic antigen in brain tumors.

Carcinoembryonic antigen (CEA) has been indicated to be a marker for brain tumors. In this study CEA was measured in serum and cerebrospinal fluid (CSF) of 14 patients with benign brain lesions, 16 with primary brain tumors and 8 with metastatic brain tumors by radioimmuno assay. Tumor cyst fluid CEA of 6 patients having intracranial tumors was also measured. The control group (n=20) had no neurological disease. The mean CEA levels in CSF for the control group, patients with benign tumors, primary tumors and metastatic tumors were 0.22 ng/ml, 0.31 ng/ml, 0.92 ng/ml, and 6.3 ng/ml respectively. Corresponding serum CEA levels were 2.5, 2.7, 3.0 and 5.2 ng/ml. Results showed that CEA level in CSF may play an important role in differential diagnosis of primary and metastatic brain tumors and consequently management of the treatment. To our knowledge this is the first such study on brain tumors from India.

Biomarkers, Tumor↗
PubMed2003

X-linked Charcot-Marie-Tooth disease with myokymia: report of a family.

The clinical and electrophysiologic profiles of two brothers suffering from Charcot-Marie-Tooth disease are presented. Both had widespread muscle twitching in the legs which showed electrophysiologic features of myokymia. Pedigree analysis suggested an x-linked recessive form of inheritance. This appears to be the first report of an Indian family with x-linked Charcot-Marie-Tooth disease.

Adolescent↗
PubMed2001

Curcuma longa activates NF-kappaB and promotes adhesion of neutrophils to human umbilical vein endothelial cells.

Upregulation of expression of cell adhesion molecules, such as ICAM-1, VCAM-1 and E-selectin, is important for immune surveillance. Extravasation and migration of body's effector cells to the site of immune activation is controlled by the expression of cell adhesion molecules on endothelial cells. We demonstrate here that an aqueous extract prepared from Curcuma longa (ClAqE), a dietary component, promotes the adhesion of peripheral neutrophils to human umbilical vein endothelial cells. To delineate the mechanism of increased adhesion, we investigated the possibility that ClAqE induces the expression of ICAM-1 and E-selectin on endothelial cells. ClAqE increases the steady state transcript levels of ICAM-1, VCAM-1, and E-selectin as determined by RT-PCR. We also show that ClAqE activates nuclear transcription factor NF-kappaB, a major transcription factor involved in the transcription of genes encoding ICAM-1, VCAM-1 and E-selectin. These results have implications for the usage of aqueous preparation of C. longa for upregulation of cell adhesion molecule expression and/or NF-kappaB.

Base Sequence↗
PubMed2001

Enhancer aided in vitro permeation of atenolol and prazosin hydrochloride through mice skin.

Effect of penetration enhancers were studied on the permeation of antihypertensive drugs prazosin hydrochloride and atenolol through full thickness skin of swiss albino mice. Atenolol was delivered to skin from saturated alcoholic solution containing 5% of 1-decanol and alcohol alone, while prazosin hydrochloride was saturated in dimethyl formamide(DMF, 5% v/v in water) and dimethyl sulfoxide(DMSO, 5% v/v in water). Atenolol permeation was augmented significantly in decanolic solution and also in pure alcohol. In case of prazosin hydrochloride, significant enhancement of permeation was shown by DMSO but not by DMF.

Administration, Cutaneous↗
PubMed2001

Spinocerebellar ataxia--type 6.

Fifty six years lady presented with pure cerebellar ataxia with positive family history from paternal side presented to our clinic. DNA screening found to be SCA6. This is the first case report of SCA6 from India.

Female↗
PubMed2001

Effect of physicochemical parameters on skin permeability of antihypertensive.

Studies were carried out to establish a correlation of skin permeability with physicochemical parameters using five antihypertensive drugs. In vitro skin permeation was carried out in vertical type diffusion cells. When steady-state fluxes of the drugs were correlated with physicochemical properties, good correlation was obtained with the reciprocal of melting point. Weak correlation was obtained with partition coefficient, molecular weight and solubility. However skin permeability versus solubility profiles revealed an interesting trend. The initial permeation rates of the poorly water soluble drugs, prazosin hydrochloride and reserpine were higher than their steady-state fluxes and moderately water soluble drug atenolol showed more or less similar permeation throughout the entire span of the study. This trend changed gradually and reversed completely in the highly water soluble drug diltiazem hydrochloride. The study suggests that drug derivatives of low melting point and good aqueous solubility could be favorable candidates for transdermal delivery.

Administration, Cutaneous↗
PubMed2000

Glucocorticoid receptor regulation in the rat embryo: a potential site for developmental toxicity?

Glucocorticoids play a key role in controlling numerous cellular processes during embryogenesis and fetal development. Excess glucocorticoids during development have been linked to dysmorphogenesis and/or intrauterine growth impairment in rodents. The actions of glucocorticoids are mediated by interaction with their receptors. Negative feedback regulation of glucocorticoid receptor (GR) is important for limiting cellular sensitivity to the hormones. Hence, acute exposure of the adult rat to the synthetic glucocorticoid dexamethasone (DEX) reduced both GR mRNA and protein in a variety of tissues that include hippocampus and liver, in a dose- and time-dependent fashion. Reduction in GR mRNA and protein were observable when DEX was given repeatedly at doses as low as 0. 05 mg/kg. In the control whole rat embryo, GR mRNA was low but measurable at as early as gestational day (GD) 10, but underwent rapid ontogenetic increase in the ensuring days. In contrast to the adult, neither GR mRNA nor protein in the whole rat embryo was affected by acute or repeated DEX administration to pregnant rats on GD10-13, even at doses as high as 0.8 mg/kg. Similar results were obtained in embryonic palate and liver, tissues known to be glucocorticoid targets. These data suggest that GR autoregulation does not occur during organogenesis in the rat. Accordingly, hormonal elevations from stress or chemical insults can be transduced unrestrictedly, ultimately leading to aberrant cell function and development. The unique mode of GR regulation seen in the embryonic cells may provide a potential common mechanism for developmental perturbation and toxicity for a variety of insults.

Analysis of Variance↗
PubMed2000

Establishment of forskolin yielding transformed cell suspension cultures of Coleus forskohlii as controlled by different factors.

Suspension cultures derived from gall calli which were obtained following infection with Agrobacterium tumefaciens (C58) were established in Coleus forskohlii. Cell line selection following single cell cloning or cell aggregate cloning was carried out to select cell lines capable of fast growth and for producing high level of forskolin. A fast growing cell line (GSO-5/7) thus selected was found to accumulate 0.021% forskolin in 42 days. The effect of cultural conditions on cell growth was studied to identify factors influencing biomass yield. Cell growth in suspension was found to be influenced significantly by carbon source, initial cell density and light or dark condition. Optimal cell growth (20 fold increase in biomass in a 42 day period) was obtained when the cells were grown in dark condition in B5O media containing 3% sucrose as sole carbon source with an initial cell density of 1.5 x 10(5) cells per ml. Forskolin accumulation was maximum (0.021%) in the stationary phase of cell growth. These suspension cultures showed continuous and stable production of forskolin.

Cell Culture Techniques↗
PubMed2000

Characterization of fibroblast cytoplasmic proteins that bind to the 3' UTR of human catalase mRNA.

The excessive expression of catalase protein and its activity in cultured skin fibroblast from Zellweger Syndrome (ZS), a disorder of peroxisomal biogenesis, was found to be regulated at the translational level (J. Neurochem. 67: 2373-2378, 1996). Overall there is a considerable increase in the association of catalase mRNA with polysomes in ZS cell lines as compared to control indicating translational upregulation. To investigate the possibility that RNA-protein interactions are involved in the mediation of this increase in translation, the interaction between 3' untranslated region of human catalase mRNA and human fibroblast cytoplasmic proteins were investigated by RNA gel shift assay technique. Competition experiments demonstrated that all the 600 bases of 3' UTR (of human catalase gene) was required for efficient binding. Catalase RNA- protein interaction was sensitive to the altered redox state in these in vitro assays and this RNA-protein interaction could be enhanced by the addition of beta-mercaptoethanol in cytoplasm from control fibroblast but not in cytoplasm from ZS fibroblast. UV cross linked RNA-protein complexes on SDS polyacrylamide gel electrophoresis revealed the presence of at least four protein bands with approximate molecular masses of 38 kDa, 50 kDa, 66 kDa and 80 kDa. The potential role of these mRNA binding proteins in the regulation of catalase gene expression is discussed.

3' Untranslated Regions↗
PubMed2000

Kidney ischemia-reperfusion: modulation of antioxidant defenses.

Reactive oxygen species (ROS; O2-, H2O2, and OH), normal by-products of cellular metabolic processes, are kept in control by antioxidant enzymes, such as catalase, glutathione peroxidase (GPX) and superoxide dismutases (SODs). To understand the role of antioxidant enzymatic defenses against ROS injury following ischemia-reperfusion, we examined the effect on kidney exposed to varying periods (30, 60 or 90 min) of ischemia followed by different periods of reperfusion. The enzymatic activities and protein levels of catalase, GPX, CuZnSOD and MnSOD were relatively unaffected at 30 min of ischemia followed by 0, 2 or 24 h reperfusion. However, 60 or 90 min of ischemia followed by 0, 2 or 24 h of reperfusion resulted in a decrease in activities and protein levels which paralleled the duration of ischemic injury. MnSOD activity tended to recover towards normal during reperfusion. Examination of the mRNA levels of these antioxidant enzymes demonstrated a severe decrease in mRNA levels of catalase and GPX at a time point of minimal ischemic injury (30 min of ischemia followed by reperfusion) suggesting that loss of mRNA of catalase and GPX may be the first markers of alterations in cellular redox in ischemia-reperfusion injury. Greater loss of mRNA for catalase, GPX and CuZnSOD was observed following longer periods (60 or 90 min) of ischemia. The mRNA for MnSOD was upregulated at all time points of ischemia-reperfusion injury. Actually, the greater decrease in mRNAs for catalase, GPX and CuZnSOD in the acute phase (within 24 h) subsequently showed a further decrease in these enzyme activities in the subacute phase (72 or 120 h after ischemia). These enzyme activities in the 30 min ischemia group, (but not in the 90 min group), already showed tendencies for normalization at 120 h after ischemia. To understand the molecular basis of the loss of mRNA of these antioxidant enzymes during ischemia-reperfusion injury, we examined the rate of transcription by nuclear run-on assays. The similar rates of transcription in control and kidney exposed to ischemia-reperfusion indicates that the loss of mRNA for catalase, GPX and CuZnSOD is possibly due to the increased rate of turnover of their mRNAs. These studies suggest that expression of antioxidant genes during ischemia-reperfusion are not coordinately expressed and that the differential loss of antioxidant enzymes may be the contributing factor(s) towards the heterogeneous renal tissue damage as a result of ischemia-reperfusion induced oxidative stress.

Animals↗
PubMed2000

2'-hydroxychalcone inhibits nuclear factor-kappaB and blocks tumor necrosis factor-alpha- and lipopolysaccharide-induced adhesion of neutrophils to human umbilical vein endothelial cells.

Inhibition of expression of cell adhesion molecules (CAM), including intercellular CAM-1 (ICAM-1), vascular CAM-1 (VCAM-1), and E-selectin, has been shown to be important in controlling various inflammatory diseases. The cell adhesion proteins are induced by various inflammatory cytokines, such as tumor necrosis factor-alpha, interleukin-1, and bacterial lipopolysaccharide. The induction process primarily takes place at the level of transcription, where nuclear factor-kappaB (NF-kappaB) plays a major role. We demonstrate here that 2'-hydroxychalcone inhibits the adhesion of peripheral neutrophils to the endothelial cell monolayers by inhibiting the expression of ICAM-1, VCAM-1, and E-selectin in a concentration-dependent manner. The inhibition by 2'-hydroxychalcone is reversible. 2'-hydroxychalcone inhibits the induction of steady-state transcript levels of ICAM-1, VCAM-1, and E-selectin by tumor necrosis factor-alpha as determined by reverse transcription-polymerase chain reaction, and therefore it may interfere with the transcription of their genes. Because NF-kappaB is a major transcription factor involved in CAM expression, we studied its status in the 2'-hydroxychalcone treated cells. We demonstrate that 2'-hydroxychalcone inhibits the activation of NF-kappaB. These results have implications for using NF-kappaB inhibitors for the treatment of various inflammatory diseases.

Biological Transport↗
PubMed2000

Immunocytochemical characterization of murine Hex, a homeobox-containing protein.

A polyclonal antibody against a glutathione S:-transferase fusion protein containing the 76 COOH-terminal amino acids of Hex, a divergent homeobox gene, was raised in rabbits. Western blot and immunofluorescence reveal that Hex is a 35-37-kD soluble protein present both in the nucleus and cytoplasm of transfected and nontransfected cultured cells as well as in whole mouse embryo. Confocal microscopy of whole mount immunostained mouse embryos at E7. 5 and E8.5 demonstrates that Hex is differentially localized in the cytoplasm and nucleus of definitive endoderm, developing blood islands, and hepatic diverticulum. In particular, in the region of the foregut that gives rise to the liver, Hex expression is nuclear in the endodermal cells of the hepatic diverticulum, whereas expression is primarily cytoplasmic in cells lateral to the liver-forming region. This suggests that nuclear localization of Hex is involved in early hepatic specification and that compartmentalization of Hex protein plays an important role in its function during mouse development.

Animals↗
PubMed2000

Comparison of skin permeability of drugs in mice and human cadaver skin.

In vitro percutaneous absorption of four antihypertensive drugs were carried out across the mice and human cavader skin in order to compare their skin permeability. An interesting trend was noticed in these experiments. Poorly water soluble drug prazosin hydrochloride showed 13 times enhanced flux in the mice skin whereas the steady-state flux of the water soluble drug propranolol hydrochloride was almost same in both human cadaver and mice skin. The permeation rate of prazosin hydrochloride and propranolol hydrochloride through the human cadaver skin fluctuated widely over time, but in mice skin, distinct trends were noticed. The study indicates that the overall permeation rate in mice skin is higher than that in the cadaver skin and the meeting of the target-flux in mice skin does not guarantee its good permeability in human skin.

Administration, Cutaneous↗
PubMed2000

Polyamines and plant alkaloids.

Naturally occurring alkaloids are nitrogenous compounds that constitute the pharmacogenically active basic principles of flowering plants. Alkaloids are classified into several biogenically related groups. Tobacco alkaloids are metabolised from polyamines and diamines putrescine and cadaverine. N-methyl transferase is the first enzyme in alkaloid biosynthetic pathway which drives the flow of nitrogen away from polyamine biosynthesis to alkaloid biosynthesis. Arginine decarboxylase has been suggested to be primarily responsible for providing putrescine for nicotine synthesis. Tryptophan is the precursor of indole alkaloids. However, the biosynthetic pathway of tropane and isoquinoline alkaloids are not clear. Genes for several key biosynthetic enzymes like arginine decarboxylase, ornithine decarboxylase, putrescine N-methyl transferase and spermidine synthase, hyoscyamine 6 beta hydroxylase,tryptophan decarboxylase etc have been cloned from different plant species. These genes are regulated by plant hormones, light, different kinds of stress and elicitors like jasmonates and their strong expression is primarily in the cultured roots. In view of this, the axenic hairy root cultures induced by Agrobacterium rhizogenes have been utilised to synthesise secondary metabolites. The current development in the knowledge of alkaloid biosynthesis, particularly molecular analysis, has been discussed in this review that may help to open up new avenues of investigation for the researchers.

Alkaloids↗
PubMed1999

Production of "authentic" poliovirus RNA-dependent RNA polymerase (3D(pol)) by ubiquitin-protease-mediated cleavage in Escherichia coli.

The first amino acid of "authentic" poliovirus RNA-dependent RNA polymerase, 3D(pol), is a glycine. As a result, production of 3D(pol) in Escherichia coli requires addition of an initiation codon; thus, a formylmethionine is added to the amino terminus. The formylmethionine should be removed by the combined action of a cellular deformylase and methionine aminopeptidase. However, high-level expression of 3D(pol) in E. coli yields enzyme with a heterogeneous amino terminus. To preclude this problem, we developed a new expression system for 3D(pol). This system exploits the observation that proteins fused to the carboxyl terminus of ubiquitin can be processed in E. coli to produce proteins with any amino acid as the first residue when expressed in the presence of a ubiquitin-specific, carboxy-terminal protease. By using this system, authentic 3D(pol) can be obtained in yields of 30-60 mg per liter of culture. While addition of a single glycine, alanine, serine, or valine to the amino terminus of 3D(pol) produced derivatives with a specific activity reduced by at least 25-fold relative to wild-type enzyme, addition of a methionine to the amino terminus resulted in some processing to yield enzyme with a glycine amino terminus. Addition of a hexahistidine tag to the carboxyl terminus of 3D(pol) had no deleterious effect on the activity of the enzyme. The utility of this expression system for production of other viral polymerases and accessory proteins is discussed.

Amino Acid Sequence↗