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Biomedical subjects

A K Banerjee

Publications and source records attributed to A K Banerjee.

At least 181 records · Page 10Linked to original sources
PubMed1992

Bifrontal oligodendroglioma with bilateral symmetrical posterior communicating artery aneurysms.

A case of bifrontal oligodendroglioma with bilateral posterior communicating artery aneurysms, one symptomatic and the other incidental, is presented. This is the first instance of such a combination. Clipping of the aneurysm, along with partial tumour excision, was performed at the same sitting, successfully. Literature on this association is reviewed and the pathogenesis is discussed.

Brain Neoplasms↗
PubMed1992

Endoscopic transthoracic sympathectomy in the treatment of hyperhidrosis.

A 5-year experience of 50 endoscopic transaxillary dorsal sympathectomies is presented. The procedure was successful in either curing or improving the symptoms of hyperhidrosis in the great majority of patients. The commonest side effects were compensatory sweating (75%) and gustatory sweating (48%); despite this, there was an extremely high level of patient satisfaction. Permanent Horner's syndrome did not occur. The procedure is effective, simple, cheap, and requires only an overnight stay; and is recommended as the method of choice for the surgical treatment of upper limb hyperhidrosis.

Adolescent↗
PubMed1992

Restricted replication of vesicular stomatitis virus in T lymphocytes is coincident with a deficiency in a cellular protein kinase required for viral transcription.

Vesicular stomatitis virus (VSV) fails to replicate in mouse T lymphocytes unless the cells have been mitogenically stimulated with concanavalin A (Con A). We have examined the possibility that the failure of VSV to replicate in unstimulated T lymphocytes can be attributed to a deficiency in a host protein kinase which activates the viral P protein by phosphorylation, thus rendering it transcriptionally competent. Soluble extracts were prepared from purified mouse T lymphocytes, with or without prior treatment with Con A. The ability of these extracts to phosphorylate bacterially synthesized P protein of two VSV serotypes was measured in vitro. Activity of the protein kinase on the P proteins of the Indiana or New Jersey serotypes of VSV increased, on average 2.4- and 2.1-fold respectively, after treatment of the cells with 3 micrograms/ml Con A. Higher concentrations of Con A induced proportional increases (up to 10-fold) in the activity of the host protein kinase. Activities of the kinase phosphorylating the P protein in separate populations of CD4- and CD8-containing murine T lymphocytes increased similarly on mitogenic activation. No biochemical or immunological differences were observed between the T cell protein kinase and the previously characterized protein kinase (casein kinase II) from BHK-21 cells. The activity of the kinase that phosphorylates the P protein did not vary in CV-1 cells on treatment with alpha- or gamma-interferon, both of which inhibited VSV replication. Similarly, casein kinase II activities in Raji and SIRC cells, which do not normally support VSV growth, were the same as in BHK-21 cells. Thus restriction of VSV replication in these cells, in contrast to T lymphocytes, was not associated with a deficiency in the host casein kinase II activity.

Animals↗
PubMed1992

Unilateral subungual hyperkeratosis following a cerebrovascular incident in a patient with psoriasis.

The prevalence of nail abnormalities in psoriasis is reported to be between 50 and 90% of affected adults. These include pitting, nail discoloration, onycholysis and subungual hyperkeratosis. Although nail changes may be associated with neurological disease, there are no previous reports of psoriatic nail changes following cerebrovascular events. We report the first case to our knowledge of unilateral subungual hyperkeratosis in a psoriatic patient which developed following a cerebrovascular event.

Cerebrovascular Disorders↗
PubMed1992

Phosphorylation of specific serine residues within the acidic domain of the phosphoprotein of vesicular stomatitis virus regulates transcription in vitro.

The phosphorylated state of the vesicular stomatitis virus phosphoprotein (P), an essential component of the virion-associated RNA polymerase complex, has been shown to be important for the transcriptional activity of the complex. Recent studies indicate that phosphorylation within the acidic domain of the P protein by cellular casein kinase II is necessary for its activity. In an attempt to identify the exact location of the cell kinase-mediated phosphorylation, we altered specific serine and threonine residues within the acidic domain of the New Jersey serotype of P protein by site-directed mutagenesis. The altered P proteins were then tested to determine what effect these mutations had on the phosphorylated state of the protein in vivo as well as its transcriptional activity in vitro. We report that serine residues 59 and 61 within the acidic domain of the P protein must be phosphorylated for it to be functionally active in a reconstituted transcription assay. These results demonstrate the importance of site-specific phosphorylation in the transcriptional activity of a negative-strand RNA viral phosphoprotein and the crucial role played by a cell protein kinase in this process.

Base Sequence↗
PubMed1992

Sequential phosphorylation of the phosphoprotein of vesicular stomatitis virus by cellular and viral protein kinases is essential for transcription activation.

The phosphoprotein (P) and the large protein (L) constitute the RNA-dependent RNA polymerase of vesicular stomatitis virus (VSV). We show that phosphate-free P protein expressed in bacteria is transcriptionally inactive when reconstituted with L protein and viral N-RNA template free of cellular protein kinase. Phosphorylation of P protein by a cellular kinase(s) was essential for transcription as well as for further phosphorylation by an L-associated kinase, the two kinases acting in a sequential (cascade) manner. Phosphate groups introduced by cell kinase were stable, whereas those due to L kinase underwent a turnover which was coupled to ongoing transcription. We present a model for the phosphorylation pathway of P protein and propose that continued phosphorylation and dephosphorylation of P protein may represent a transcriptional regulatory (on-off) switch of nonsegmented negative-strand RNA viruses.

Animals↗
PubMed1992

Studies of gut mucosal protein synthesis in a non-steroidal anti-inflammatory drug (NSAID) model of inflammatory bowel disease.

The extent to which defects in protein synthesis occurred in an experimental indomethacin induced rat model of nonsteroidal enteropathy has been examined. Male rats (nine) were fed indomethacin (8 mg/kg/day) for three days mixed with a powdered form of chow. The control group of rats (nine) were fed the same diet for three days without indomethacin. After the feeding period, both groups were fed a normal solid diet for four days. At the end of this period, the fractional rates of intestinal protein synthesis was determined by the 'flooding dose' technique. The mucosal protein, RNA and DNA contents in the proximal ileum of animals with enteropathy were not significantly different from controls (p greater than 0.05). Experimental enteropathy induced selective increases in the fractional rates of protein synthesis (26% increase, p less than 0.03) and RNA activities (23% increase, p less than 0.04). There were no significant changes in any of these variables in the duodenum (p greater than 0.05 in all instances). These changes may partly reflect the activity of those processes responsible for the pathogenic changes in NSAID enteropathy.

Animals↗
PubMed1992

Intracranial olfactory neuroblastoma: evidence for olfactory epithelial origin.

AIMS: To determine the possible histogenesis of the intracranial variant of olfactory neuroblastoma. METHODS: Four specimens from three cases of intracranial olfactory neuroblastoma were studied by light microscopy and immuno-histochemistry, and electron microscopy in two cases. RESULTS: Light microscopical examination showed small cell tumour with additional features of epithelioid cells in one case and ganglion cells in another. Olfactory and Homer-Wright rosettes were present. All the specimens showed a uniform positive reaction to neurone specific enolase, S-100, and cytokeratin antibodies. Glial fibrillary acidic protein was absent. The salient electron microscopic features were the presence of cell junctions, cytoplasmic intermediate filaments, basal bodies and cytolasmic processes. Dense cored vesicles were absent. CONCLUSIONS: The results strongly support the view that intracranial olfactory neuroblastomas are of olfactory epithelial origin and differ from conventional neuroblastomas.

Adult↗
PubMed1992

Lack of smooth muscle in the small pulmonary arteries of the native Ladakhi. Is the Himalayan highlander adapted?

Chronic hypobaric hypoxia induces a mild degree of pulmonary arterial hypertension with structural alterations in the peripheral portions of the pulmonary arterial tree of the native Andean highlanders. On the other hand, animals indigenous to high altitude do not show these changes and are adapted to hypobaric hypoxia. The small pulmonary arteries of seven native Himalayan highlanders were examined at autopsy and found to be thin-walled with no medial hypertrophy of the muscular pulmonary arteries or muscularization of the arterioles. These findings suggest that the Himalayan highlanders may be adapted to hypobaric hypoxia.

Adaptation, Physiological↗
PubMed1992

Role of the phosphoprotein (P) in the encapsidation of presynthesized and de novo synthesized vesicular stomatitis virus RNA by the nucleocapsid protein (N) in vitro.

Encapsidation of presynthesized and nascent (synthesized de novo) vesicular stomatitis virus (VSV) leader RNA in vitro by the nucleocapsid protein (N) and the role of the phosphoprotein (P, previously known as NS) in this process were examined. Presynthesized VSV leader RNAs were derived from the SP6 transcription vectors containing both (+) and (-) leader genes while the nascent RNA was derived from transcription of viral ribonucleoprotein (RNP) complex. The N and the P proteins were made by transcription from SP6 vectors containing the genes, followed by translation of the mRNAs in rabbit reticulocyte lysate. Here, we demonstrate that the N protein alone encapsidated presynthesized VSV leader RNA; however, prior formation of N-P complex totally abolished the encapsidation property of N. On the other hand, encapsidation of nascent RNA by the N protein was stimulated by the N-P complex. These results suggest that encapsidation by the N protein of presynthesized and nascent VSV RNA are separate biochemical processes which can be distinguished by the differential role of the phosphoprotein P in the two reactions.

Capsid↗
PubMed1992

Fine needle aspiration biopsy--a critical investigation in thyrotoxicosis.

Four hundred and fifty two patients having clinical features of thyrotoxicosis have been studied for their hormonal (T4, T3 and TSH) content, I131 uptake levels and FNAB at repeated intervals. Four hundred and twenty seven had presented with diffuse enlargement and rest 25 cases with nodular enlargements. Of the primary hyperthyroidism cases 342 (82.4%) were of Grave's disease without exophthalmos and 73 (17.6%) with exophthalmos. T4, T3 and I131 uptake levels have correlated well with the degree of morphological changes as observed on FNAB. Degree of nuclear pleomorphism has correlated well with the duration of disease. Critical evaluation of morphological changes on FNAB has been done in all cases of primary hyperthyroidism being treated with neomercazole and radioactive iodine therapy. Treatment with neomercazole had shown, good correlation between time lag and the retrogressive changes. This was not so in cases treated with radioactive iodine therapy. Various known complications of radioactive treatment e.g. development of hypothyroidism, refractory and recurrent hyperthyroidism, exacerbation of the disease, radiation thyroiditis, and severe degree of dysplastic changes could be demonstrated in some cases on serial aspirations.

Biopsy, Needle↗