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Biomedical subjects

A K Banerjee

Publications and source records attributed to A K Banerjee.

At least 271 records · Page 15Linked to original sources
PubMed1989

Role of dopamine receptors in gastrointestinal motility.

Apomorphine (3.5 and 10 mg/kg, s.c.) and morphine (1.3 and 10 mg/kg, s.c.) produced a dose-dependent decrease in gastrointestinal transit of charcoal dust in rats. The involvement of dopamine in such a constipatory effect was found to be mediated to a greater extent by DA2 than by DA1 receptors, using a specific DA1 antagonist (SCH 23390) and DA2 antagonists (alizapride, domperidone). The decrease in apomorphine (50 micrograms) and dopamine (100 and 200 micrograms)-induced gastrointestinal transit after intracisternal administration was antagonized by haloperidol. These results provide evidence for the involvement of dopamine receptors in the constipatory effects of apomorphine and morphine in rats.

Animals↗
PubMed1989

Analgesic effect of tramadol in the rat.

The analgesic effect of tramadol was studied in the rat using tail flick and hot plate tests following intrathecal and subcutaneous administrations. Tramadol had only a short-lasting analgesic effect (20 min) on intrathecal administration which may be due to rapid removal from the subarachnoid space. Its analgesic effects were antagonized by pretreatment with naloxone. It seems that the opiate system may involve in the analgesic effect of tramadol, while the noradrenergic, serotonergic and cholinergic systems may play a modulating role.

Analgesics↗
PubMed1989

Medulloblastoma in adults--clinical observations and results of treatment.

Ten cases of medulloblastomas, in patients above the age of 15 years, were treated during a 11 year period. These constituted 18 percent of all medulloblastomas and 1.2 percent of all primary brain tumours in adults during the same period. The majority of patients (80%) were between 16 and 25 years of age, and 80 percent were male. Half the patients presented within three months of the onset of symptoms. The usual clinical presentation was with features of raised intracranial pressure and cerebellar involvement. A lateral location of the tumour and its desmoplastic variant were common. Three patients survived more than five years. The desmoplastic variant and a gross total resection of the tumour favourably affected the prognosis. Posterior fossa recurrence was the chief cause of therapeutic failures. All the recurrences developed within three years of the initial diagnosis, and were fatal within six months of their detection.

Adolescent↗
PubMed1989

Lupus nephritis--light, electron and immunofluorescent microscopy (a clinicopathological study).

Kidney biopsy specimens from nine patients of systemic lupus erythematosus were studied for the purpose of correlating the findings of light and electron microscopy and immunofluorescent studies with the kidney functions and the presence of proteinuria. Morphologically, three were mesangiocapillary glomerulonephritis, three mesangioproliferative glomerulonephritis and one membranous nephropathy. Subendothelial deposits were observed in eight cases, subepithelial deposits in seven cases and mesangial deposits in eight cases. Four cases with massive subendothelial deposits had massive proteinuria and decrease in renal functions. Most of the patients with mild subendothelial deposits were considered to be useful in assessing the prognosis and severity of lupus nephropathy, in addition to the morphologic types of lesions, as mesangial pattern had shown insignificant proteinuria. Study of semithin sections by light microscopy could demonstrate the deposits which were observed on electron microscopy and immuno-fluorescent microscopy.

Adult↗
PubMed1988

Analysis of the tachycardiac response to 5-hydroxytryptamine in the spinal guinea-pig.

The mechanism of the increase in heart rate caused by 5-hydroxytryptamine (5-HT) in the spinal guinea-pig was investigated. Administration of 5-HT (15, 30, 60 and 120 micrograms.kg-1 i.v.) elicited dose dependent increases in heart rate. The responses to 5-HT were not modified by methiothepin (0.5 and 1.5 mg.kg-1), ketanserin (0.5-4.5 mg.kg-1) or MDL 72222 (0.5-4.5 mg.kg-1) but were antagonized by the beta-adrenoceptor antagonists, propranolol (0.1-1 mg.kg-1) or atenolol (0.5-4.5 mg.kg-1). Indalpine, which is known to interfere with the uptake of 5-HT by nerve terminals and blood platelets, significantly reduced the effects of 5-HT at a dose (5 mg.kg-1) that also affected the tachycardia elicited by tyramine. The increase in heart rate caused by tyramine in reserpinized animals was attenuated and, unlike normal animals where the responses to 5-HT remained constant after repeated administration, there was a quickly developing tachyphylaxis to 5-HT. These results show that the increase in heart rate elicited by 5-HT in spinal guinea-pigs is not mediated by any of the currently characterized 5-HT receptors ('5-HT1-like', 5-HT2 and 5-HT3), and that a major part of the tachycardia seems to be mediated by a release of catecholamines by a mechanism similar, though perhaps not identical, to that for tyramine. Another as yet unidentified mechanism could be involved besides though perhaps not identical, to that for tyramine. Another as yet unidentified mechanism could be involved besides this action.

Adrenergic beta-Antagonists↗
PubMed1988

The functional domains of the phosphoprotein (NS) of vesicular stomatitis virus (Indiana serotype).

A full-length cDNA clone of the mRNA encoding the phosphoprotein (NS) of the Indiana serotype of vesicular stomatitis virus was inserted into the SP6 transcription vector. By in vitro transcription of the inserted gene followed by translation of the mRNA in a rabbit reticulocyte lysate, NS protein was synthesized. The biological activity of the protein was demonstrated by RNA synthesis in vitro by reconstitution with L protein and N-RNA template purified from virions. Using oligonucleotide-directed RNase H cleavage of the full-length NS mRNA, a series of deleted RNAs were made which gave rise to corresponding size classes of truncated NS protein after translation in vitro. The N-RNA template binding site was located at the C-terminal domain (21 amino acids) of the NS protein and the L-protein binding site was present within 14 amino acids spanning the NH2-terminal side of the N-RNA binding site. These results are similar to that obtained with the NS protein of the New Jersey serotype of VSV, indicating conservation of the functional domains within the VSV serotypes.

Biological Evolution↗
PubMed1988

Intradural extramedullary tuberculous spinal granulomas.

Four cases of intradural extramedullary tuberculous spinal granulomas without bony involvement are presented. Both, the rarity of the disease, as well as the successful microsurgical resection with good recovery prompted this report. The pathogenesis with the controversies therein, is discussed and pertinent literature is reviewed.

Adolescent↗
PubMed1988

NH2-terminal acidic region of the phosphoprotein of vesicular stomatitis virus can be functionally replaced by tubulin.

The phosphoprotein (NS) of vesicular stomatitis virus is an indispensable subunit of the virion-associated RNA polymerase (L). NS consists of a highly acidic NH2-terminal domain and a basic COOH-terminal domain. Unlike the latter, the amino acid sequences of the NH2-terminal regions are highly dissimilar among different viral serotypes, although they share structural similarities. We have cloned an NS gene into the SP6 transcription vector and replaced the 5'-terminal 80% by a full-length gene for beta-tubulin, which contains an acidic COOH-terminal domain. Here we present evidence that the chimeric tubulin-NS protein is biologically active and that the acidic region in tubulin directly affects the transcription reaction. These observations indicate that NS probably functions as an activator protein in which the acidic domain stimulates transcription of the viral genes by interacting with the RNA polymerase as observed for eukaryotic cellular transcription activators.

Amino Acid Sequence↗