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Biomedical subjects

P Banerjee

Publications and source records attributed to P Banerjee.

At least 73 records · Page 4Linked to original sources
PubMed1996

Stable expression and heterologous coupling of the kappa opioid receptor in cell lines of neural and nonneural origin.

Signal transduction cascades initiated by the neuronal kappa opioid receptor were studied following transfection of a neuronal (hippocampal) line, HN2, and the non-neural CHOs. Retinoic-acid mediated differentiation resulted in intense staining of the HN2 cells with a neurofilament protein antibody SMI 33 but not with an antibody to GFAP, thus establishing neuronal characteristics of the HN2 cell line. The kappa opioid receptor was stably expressed in the two cell lines by electroporation mediated transfer of a Cytomegalovirus-promoter driven construct, pCMV-kappa, harboring the kappa-opioid receptor cDNA. Positive clones (HN2 kappa 24 and CHO kappa 18) from both lines showed high expression of the kappa opioid receptor, as identified by [3H] U-69,593 binding to membranes prepared from HN2 kappa 24 and CHO kappa 18. Scatchard analysis revealed the presence of high affinity kappa opioid receptors in both engineered cell lines (KD=1.3 nM for HN2 kappa 24 and 2.1 nM for CHO kappa 18). Functional coupling to adenylate cyclase was displayed by 1 microM U-69,593 mediated inhibition (55-63%) of prostaglandin E1-stimulated intracellular cAMP levels. A major difference between the two clones was observed in functional coupling of the expressed kappa opioid receptor to phospholipases C (PL-C) and D (PL-D). U-69,593 (1 microM) treatment stimulated PL-C, but not PL-D, in HN2 kappa 24 cells, whereas PL-D, but not PL-C, was stimulated following such treatment of CHO kappa 18 cells. Our results using the model neuronal system, HN2 kappa 24, demonstrate cell-type specific, positive coupling of the kappa opioid receptor to the major Ca2+ mobilizing system, the PL-C cascade, which regulates neuronal firing.

Adenylyl Cyclases↗
PubMed1996

Significantly different fatty acid profiles in various phospholipid head groups of neuroblastoma cell lines.

We studied lipid profiles of hybrid cells derived from fusion of sympathetic ganglia and neuroblastoma cells (NCB 20, F 11) and also CHO (Chinese hamster ovary) cells. The proportion of saturated to unsaturated fatty acids changed significantly in different phospholipid fractions. We observed 35.4% of total fatty acids as saturated fatty acids in the phosphatidyl ethanolamine (PE) fraction of NCB-20 cell lines while 47.2% of total fatty acids were saturated in the phosphatidyl inositol (PI) fraction. In general, in neuroblastoma cell lines, we observed the lowest proportion of saturated fatty acids in the PE fraction while the other lipid fraction showed a much higher proportion of saturated fatty acids. On the other hand the PE fraction of a non neuronal cell line, CHO, showed 57.4% saturated fatty acids in the PE fraction. This significant difference in saturated to unsaturated fatty acid ratios in different phospholipid head groups may be linked to the different biological functions of those hybrid cells.

Animals↗
PubMed1996

Induction of the serotonin1A receptor in neuronal cells during prolonged stress and degeneration.

Neuronal migration in brain is followed by differentiation of committed neurons and simultaneous apoptosis of uncommitted preneuronal cells due to a limiting supply of trophic factors and nutrients. We have dissected differentiation and apoptosis by designing a simple in vitro model for this nutrient deprivation using engineered neuronal cell lines stably transfected with a promoterless segment (G-21) of the intronless human serotonin1A receptor (5-HT1A-R) gene. Despite the use of widely different heterologous promoters (cytomegalovirus and Rous sarcoma virus) for the stable expression of G-21, a dramatic increase in expression of the 5-HT(1A)-R (five- to 15-fold) and its mRNA was always observed during degeneration and apoptosis of nutrient-deprived neuronal cells. Involvement in this induction of a 170-bp 5'-end untranslated sequence (5'-UT) (tail end of the 500-bp natural promoter) of G-21 was confirmed by stable transfection of neuronal cells with an SV-40 promoter-driven construct harboring the 5'-UT and the reporter chloramphenicol acetyltransferase (CAT) cDNA. Presence of the 5'-UT resulted in a threefold increase in CAT expression during nutrient deprivation in randomly chosen clones. The induction was also observed in the endogenous 5-HT1A-R, expressed by embryonic day 16 mouse hippocampal neurons, subsequent to nutrient deprivation and onset of degeneration. A trophic role of the 5-HT1A-R has been suggested in earlier studies. Considering the example of protective heat shock proteins, which are induced during various types of stress, our results suggest that stressed neuronal cells undergoing degeneration and apoptosis synthesize increased levels of 5-HT1A-R as a final attempt to survive.

Animals↗
PubMed1996

Association of immunological changes with clinical efficacy in atopic eczema patients treated with traditional Chinese herbal therapy (Zemaphyte).

The efficacy of the Chinese herbal therapy (Zemaphyte) has been well established as a treatment for atopic eczema (AE) in clinical trials. The purpose of this study was to probe the immunological changes that occurred when patients were treated with the herbs for a period of 8 weeks. This treatment decreased serum IgE complexes (p less than 0.05) but did not affect total serum IgE or CD23 expression on peripheral blood monocytes. Peripheral blood mononuclear cells from patients before and after treatment were cultured overnight with interleukin 4 and the ability of this cytokine to induce CD23 on monocytes from treated patients was found to be significantly diminished (p less than 0.01). Soluble interleukin 2 receptor and soluble vascular cell adhesion molecule were both raised in the serum of AE patients compared to control individuals. Both these parameters were decreased following treatment (p less than 0.05). All these changes coincided with improvement in erythema and surface damage scores. There was no alteration in soluble intracellular adhesion molecule or soluble CD23. The results of these investigations would suggest that this herbal treatment has the ability to target various immunological parameters which may be involved in the pathogenesis of AE.

Administration, Oral↗
PubMed1996

A lymphatic filarial survey revealing a focus of Brugia malayi in the coastal region of west Bengal.

Random night blood samples were examined from 528 subjects in an endemic zone of lymphatic filariasis, in the coastal region of West Bengal. There were 136 cases out of 528 who were symptomatic, with or without recurrent episodes of fever, lymphangitis and lymphadenitis and with various degrees of lymphoedema. Examination of blood samples revealed microfilaria in 43 cases of which 42 were asymptomatic and only one was symptomatic with lymphoedema. All the microfilariae were of the species Brugia malayi.

Adolescent↗
PubMed1995

Differential solubilization of lipids along with membrane proteins by different classes of detergents.

Membrane proteins are typically extracted by detergent concentrations of 0.5-2.0%, using detergent/protein ratios of 1:1 to 3:1. We have compared the ability of 14 different detergents from seven different structural and ionic classes, at a concentration of 2.0% and a detergent/protein ratio of 2:1, to extract an integral membrane protein (the serotonin 5-HT1A receptor) in active form and have observed profound differences in both lipids and proteins. All extracts were freed from detergents and dialyzed to form vesicles containing 95-100% of the extracted lipids, prior to [3H]8-hydroxy-2-(N,N-di-n-propylamino)tetralin ([3H]8-OH-DPAT) binding. The most efficient detergents in extracting active 5-HT1A receptor protein were the zwitterionic 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS) and 3-[(cholamidopropyl)dimethylammonio]-2-hydroxy-1-propanesulfonate (CHAPSO), followed by the neutral n-dodecyl-beta-D-maltoside. Zwitterionic detergents also produced the highest solubilized lipid/protein ratio (3.0 and 2.5, respectively) and in general the relative amounts of extracted lipids and proteins followed inverse profiles. Thus, hydrophobic detergents such as Tritons (with critical micelle concentrations similar to CHAPS) and Thesit (structurally similar to Lubrol) extracted the most protein, but relatively little lipid (ratios of less than 0.2) and very little active 5-HT receptor. Dramatic differences were also observed in the ratios of individual lipids extracted by the same concentrations of different detergents and resolved by high-performance thin-layer chromatography. For example, galactosylceramide (GalCer) content ranged from 2.7% (CHAPSO) to 13.4% (sodium cholate) of the total lipid extract and cholesterol ranged from 0% (digitonin) to 17.9% (Triton X-100). The detergent-extractability profile for phosphatidylethanolamine (PE) (range 15-40% of total lipid) paralleled that of phosphatidylinositol (PI) (range 4-10%), but was inverse to that for GalCer and cholesterol. Detergent-extractability profiles for phosphatidylcholine (PC) and phosphatidylserine (PS) also followed inverse profiles, with zwitterionic detergents giving high PS/PC and high PE/PC ratios (approximately 2:1), whereas the Tritons and digitonin gave ratios of 1:2. We believe that differential solubilization of lipids, as well as proteins, by detergents is important for the biological activity of the extracted proteins, and lipid extractability should be taken into account when purifying membrane proteins.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1995

Hyperammonemia increases serotonin 1A receptor expression in both rat hippocampus and a transfected hippocampal cell line, HN2-5.

Hyperammonemia is an important cause of cerebral dysfunction in liver failure. We used two well-established models to induce hyperammonemia in rats, injection of urease and injection of methionine sulfoximine (MSO). Urease gave a 10-fold increase in blood ammonia while MSO, a glutamine synthetase inhibitor, gave a 4-fold increase in blood ammonia with no increase in brain glutamine levels. We observed a 2-fold increase in 5-HT1A receptor (5-HT1A-R) expression ([3H] 8-OH-DPAT binding) in hippocampus, and little change elsewhere, including thalamus in both models, thus eliminating a role for increased glutamine in the receptor induction. In contrast, a 4 to 8-fold increase in 5-HT1A-R mRNA was observed both in hippocampus and thalamus, suggesting some post-transcriptional regulation. In the absence of glutamine, ammonium acetate treatment of a hippocampal cell line which had been engineered to stably express the 5-HT1A-R (HN2-5) gave a 1.5-fold increase in [3H] 8-OH-DPAT binding and a 4-fold increase in the mRNA levels for the 5-HT1A-R. We conclude that the cell line HN2-5 is a good model for studying some of the biochemical sequelae of hyperammonemia and that changes in brain function are not only at the metabolic level, as thought earlier, but can also occur at the transcriptional level.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1995

Serum zinc level : a possible index in the pathogenesis of peptic ulcer syndrome.

The present investigation shows a possible correlation between serum zinc level and peptic ulcer disease/syndrome and a plausible mechanism for the finding. Clinicopathological study of patients with peptic ulcer diseases followed by confirmed endoscopic findings shows a significant low serum zinc level, 0.846 +/- 0.15 ug/ ml +/- S.D. (P < 0.001) with an exception of approx. 10% of the patients. To understand the cellular mechanism of low zinc levels in serum, tissue zinc content of gastric mucosa was determined. A significant increased value (P < 0.01) of zinc content in gastric mucosa of patients with peptic ulcer diathesis was noted. Carbonic anhydrase, a major zinc containing enzyme was also determined in erythrocytes. However, no change of erythrocyte carbonic anhydrase content was noted. To assess the nutritional status of the patients in relation to the low serum zinc value, serum albumin level was also determined. The low serum zinc level of the peptic ulcer patients is possibly due to the positive shift for the zinc from serum to the gastric mucosa.

Carbonic Anhydrases↗
PubMed1995

Serosurvey of chikungunya antibody in Calcutta metropolis.

Since its first isolation in Calcutta, in 1963, there have been many reports about epidemis of chikungunya virus infection in different parts of India. Calcutta experienced a concurrent epidemic of dengue and chikungunya between 1963 and 1965. But after that there is no report about any chikungunya infection in Calcutta. During routine investigations it is found that chikungunya antibody is on the wane. The present survey for chikungunya antibody showed only 4.37% (n = 17) seropositivity out of 389 sera tested. The highest (12.5%) seropositivity was observed in the age group of 51-55 years and no chikungunya antibody was detected in young and young adults. The findings suggest that chikungunya virus is disappearing from the Calcutta population.

Adolescent↗
PubMed1995

Propagation of Mycobacterium lepraemurium on supplemented minimal medium and its experimental pathogenesis.

The splenic tissue of a mouse experimentally infected with M. lepraemurium (Hawaiian strain, M-65) and developing 'rat leprosy', yielded a pure culture of an acid - fast bacterium having all the characteristics of M. lepraemurium on mineral salt minimal medium supplemented with simple sources of C and N, e.g., NH4 -salts, liquid paraffin, urea, gelatin etc. This could be maintained, by serial passages in vitro with good growth. Its indefinite propagation with tissue - free washed, small inoculum on complex media including Ogawa medium was difficult, and its serial sub-culture was practically impossible. The in vitro isolate from supplemented minimal medium could produce pathological lesions in mice typical of rat leprosy.

Animals↗
PubMed1994

The stress-activated protein kinase subfamily of c-Jun kinases.

The mitogen-activated protein (MAP) kinases Erk-1 and Erk-2 are proline-directed kinases that are themselves activated through concomitant phosphorylation of tyrosine and threonine residues. The kinase p54 (M(r) 54,000), which was first isolated from cycloheximide-treated rats, is proline-directed like Erks-1/2, and requires both Tyr and Ser/Thr phosphorylation for activity. p54 is, however, distinct from Erks-1/2 in its substrate specificity, being unable to phosphorylate pp90rsk but more active in phosphorylating the c-Jun transactivation domain. Molecular cloning of p54 reveals a unique subfamily of extracellularly regulated kinases. Although they are 40-45% identical in sequence to Erks-1/2, unlike Erks-1/2 the p54s are only poorly activated in most cells by mitogens or phorbol esters. However, p54s are the principal c-Jun N-terminal kinases activated by cellular stress and tumour necrosis factor (TNF)-alpha, hence they are designated stress-activated protein kinases, or SAPKs. SAPKs are also activated by sphingomyelinase, which elicits a subset of cellular responses to TNF-alpha (ref. 9). SAPKs therefore define a new TNF-alpha and stress-activated signalling pathway, possibly initiated by sphingomyelin-based second messengers, which regulates the activity of c-Jun.

3T3 Cells↗
PubMed1994

Mitogen-activated protein kinase/extracellular signal-regulated protein kinase activation by oncogenes, serum, and 12-O-tetradecanoylphorbol-13-acetate requires Raf and is necessary for transformation.

The protein kinase cascade Raf-MAPKK/MEK-MAPK/ERK connects protein tyrosine kinase receptors in the membrane with control of transcription factor activity in the nucleus. We have examined whether Raf is obligatory for activation of this cascade and whether this signaling pathway is relevant to transformation. By use of transient assays with epitope-tagged ERK-1 cDNA and a dominant inhibitory mutant of Raf-1 we found that serum and 12-O-tetradecanoylphorbol-13-acetate as well as representatives of three classes of oncogenes (protein tyrosine kinases abl/src, Ras, and protein serine/threonine kinases mos/cot) were all Raf-dependent for stimulation of MAPK. All of the MAPK stimulating oncogenes were also activators of Raf kinase as judged by shift induction. It thus appears that there is little or no redundancy in pathways used by growth regulators for activation of MAPK/ERK. Furthermore, the ability to stimulate MAPK/ERK appears to be critical for transformation by oncogenic Raf-1 and ERK-1 and -2 synergized with v-raf in a focus induction assay on NIH3T3 cells and kinase dead mutants of ERK-2 were inhibitory. Raf/ERK synergism was also observed in transcriptional transactivation of the oncogene-response element in the polyoma enhancer. We conclude that this Raf signaling pathway, which connects to many upstream activators and downstream effectors, is essential for transformation by most oncogenes.

3T3 Cells↗
PubMed1994

Preferential beta-hexosaminidase (Hex) A (alpha beta) formation in the absence of beta-Hex B (beta beta) due to heterozygous point mutations present in beta-Hex beta-chain alleles of a motor neuron disease patient.

Deficiency of the lysosomal enzyme beta-hexosaminidase B (beta-Hex B) (a homodimer, beta beta), caused by a defect in the HEX B gene encoding the beta-chain, is usually accompanied by an absence of beta-Hex A (a heterodimer, alpha beta), thereby causing Sandhoff disease. However, we have earlier demonstrated the presence of partial beta-Hex A (30-50% of normal) even in the absence of beta-Hex B in an adult with motor neuron disease. The patient is a compound heterozygote with normal beta-chain message and one HEX B point mutation originating from each asymptomatic parent. Since the non-expression of beta-Hex B was post-transcriptional, we transfected COS-7 cells to understand the effect of each mutation on beta-Hex B activity. Transfection of the A1367-->C mutant (maternal allele) construct produced no overexpressed beta-Hex B, indicating that the encoded Tyr456-->Ser beta-chain was non-functional. Chou-Fasman analysis predicted that the Tyr456-->Ser mutation would cause a dramatic change in beta-chain folding (which often inhibits formation of functional dimers). This explains the complete lack of beta-Hex B in the transfectants and a partial deficiency of beta-Hex A and B (50% of normal) in the patient's mother. Since immunoprecipitated beta-Hex A (alpha beta) protein from patient fibroblasts showed the presence of mature beta-chains even though there was no beta-Hex B (beta beta) protein, the mutant beta-chain inherited from the father (who has normal beta-Hex A and B) must undergo preferential association with the normal alpha-chains in the patient, thus producing only beta-Hex A. Transient expression of the A619-->G mutant (paternal allele) construct produced beta-Hex B activity comparable to the wild type (approximately 10-20-fold over mock-transfected) whereas stable expression produced normal message but no beta-Hex B activity (wild type beta-Hex B expression: only 2-fold over mock-transfected). The lack of increased beta-Hex B after stable expression of the Ile207-->Val beta-chains at a lower copy number indicates the absence of self-association at low concentrations of Ile207-->Val beta-chain. In the patient who also has a non-functional Tyr456-->Ser allele, the effective concentration of beta-chains is reduced to 50% of normal and the remaining Ile207-->Val beta-chains fail to self-associate but can still dimerize with the abundant normal alpha-chains thus producing partial beta-Hex A and no beta-Hex B.

Adult↗
PubMed1994

Identification of a locus, distinct from RDS-peripherin, for autosomal recessive retinitis pigmentosa on chromosome 6p.

We performed a genomic search for linkage to autosomal recessive retinitis pigmentosa in a large pedigree obtained from the Dominican Republic using microsatellite markers. Regions of the genome known to contain genes for retinitis pigmentosa were preferentially tested. One of these regions, on chromosome 6p, which contains the gene for peripherin, gave positive lod scores. Use of a mononucleotide repeat polymorphism in the peripherin gene excluded this locus. Two- and multi-point analyses suggest that the most likely location for the disease gene is near D6S291, which is located approximately 20 centimorgans telomeric from peripherin.

Chromosomes, Human, Pair 6↗