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Biomedical subjects

A K Banerjee

Publications and source records attributed to A K Banerjee.

At least 91 records · Page 5Linked to original sources
PubMed1997

Intracranial fungal granuloma.

BACKGROUND: Intracranial fungal granulomas are uncommon and their pathogenesis, clinical picture, and effectiveness of therapy remains unclear. METHODS: Thirty-two cases were studied retrospectively in two groups: (1) Rhinocerebral group (22 cases) had a chronic paranasal sinus (PNS) disease with secondary involvement of skull base, cranial nerves, and/or brain. The granulomas were adherent to dura, firm, avascular, and tough, requiring a knife to cut. (2) Primary intracranial group (10 cases) had no detectable PNS lesion at initial presentation. The granulomas were soft, suckable, and contained pus or necrotic material. RESULTS: Postoperative and overall mortality were 37.5% and 50%, respectively. Meningoencephalitis was the most common cause of death. Altered sensorium, pus in the granuloma, and/or severe brain edema were poor prognostic factors. All survivors except four have symptomatic residual or recurrent lesions. CONCLUSION: Early diagnosis with MRI or stereotactic biopsy, radical surgery, and high dose and chronic suppressive chemotherapy may improve overall results in these cases.

Adolescent↗
PubMed1997

Inhibition of vesicular stomatitis virus in cells constitutively expressing an antisense RNA targeted against the virus RNA polymerase gene.

To study the effect of virus-specific antisense RNA expression on vesicular stomatitis virus (VSV) infectivity in cultured cells, a HeLaS3 cell line constitutively expressing antisense RNA complimentary to a portion of the VSV large RNA-dependent RNA polymerase gene (L) was established (HeAntiL). At an m.o.i. of 0.01 or 0.1, the HeAntiL cell line was able to reduce virus titre and delay virus-induced cell death by 9 or 5 h, respectively, when compared to a HeLa cell line stably transfected with the expression vector devoid of antisense sequence. Ribonuclease protection experiments showed a 10-20-fold reduction of hybridizable virus L mRNA in infected HeAntiL cells compared to infected control cells at various times before cell death. These results indicate that the antisense RNA approach can significantly reduce VSV mRNA transcription and virus production for a reasonable period of time. The robust growth rate of VSV eventually overwhelms the available antisense RNA and leads to delayed cell death.

Genes, Viral↗
PubMed1997

Phosphorylation within the amino-terminal acidic domain I of the phosphoprotein of vesicular stomatitis virus is required for transcription but not for replication.

Phosphorylation by casein kinase II at three specific residues (S-60, T-62, and S-64) within the acidic domain I of the P protein of Indiana serotype vesicular stomatitis virus has been shown to be critical for in vitro transcription activity of the viral RNA polymerase (P-L) complex. To examine the role of phosphorylation of P protein in transcription as well as replication in vivo, we used a panel of mutant P proteins in which the phosphate acceptor sites in domain I were substituted with alanines or other amino acids. Analyses of the alanine-substituted mutant P proteins for the ability to support defective interfering RNA replication in vivo suggest that phosphorylation of these residues does not play a significant role in the replicative function of the P protein since these mutant P proteins supported replication at levels > or = 70% of the wild-type P-protein level. However, the transcription function of most of the mutant proteins in vivo was severely impaired (2 to 10% of the wild-type P-protein level). The level of transcription supported by the mutant P protein (P(60/62/64)) in which all phosphate acceptor sites have been mutated to alanines was at best 2 to 3% of that of the wild-type P protein. Increasing the amount of P(60/62/64) expression in transfected cells did not rescue significant levels of transcription. Substitution with other amino acids at these sites had various effects on replication and transcription. While substitution with threonine residues (P(TTT)) had no apparent effect on transcription (113% of the wild-type level) or replication (81% of the wild-type level), substitution with phenylalanine (P(FFF)) rendered the protein much less active in transcription (< 5%). Substitution with arginine residues led to significantly reduced activity in replication (6%), whereas glutamic acid substituted P protein (P(EEE)) supported replication (42%) and transcription (86%) well. In addition, the mutant P proteins that were defective in replication (P(RRR)) or transcription (P(60/62/64)) did not behave as transdominant repressors of replication or transcription when coexpressed with wild-type P protein. From these results, we conclude that phosphorylation of domain I residues plays a major role in in vivo transcription activity of the P protein, whereas in vivo replicative function of the protein does not require phosphorylation. These findings support the contention that different phosphorylated states of the P protein regulate the transcriptase and replicase functions of the polymerase protein, L.

Amino Acid Substitution↗
PubMed1997

Expression and purification of vesicular stomatitis virus N-P complex from Escherichia coli: role in genome RNA transcription and replication in vitro.

The nucleocapsid protein (N) and phosphoprotein (P) genes of vesicular stomatitis virus (VSV), Indiana serotype, were coexpressed in Escherichia coli BL21(DE3) by using the expression vector pET-3a. The coexpression resulted in the formation of N-P complex. The purified N-P complex was found to inhibit transcription in vitro mediated by viral ribonucleoprotein (RNP) complex in a dose-dependent manner. However, addition of uninfected mammalian cell extracts together with the N-P complex to the transcribing RNP resulted in the synthesis of full-length negative-strand genome RNA. These results indicate that the N-P complex regulated transcription and a cellular factor(s) in combination with the N-P complex may switch the RNA polymerase from transcription to replication mode.

Cloning, Molecular↗
PubMed1997

An infectious clone of human parainfluenza virus type 3.

A full-length clone of the human parainfluenza virus type 3 (HPIV-3) genome (called pHPIV-3) was constructed, and recombinant, infectious HPIV-3 was generated by transfecting pHPIV-3 and support plasmids encoding the HPIV-3 NP, P, and L proteins into HeLa cells infected with a vaccinia virus recombinant which expresses T7 RNA polymerase. T7 RNA polymerase promoters on the transfected plasmids direct the synthesis of transcripts encoding the NP, P, and L proteins and a full-length, positive-sense copy of the HPIV-3 genome. Generation of virus was dependent on transfection of pHPIV-3 and the HPIV-3 P- and L-encoding plasmids. However, a plasmid encoding the NP protein was not required since NP was expressed from pHPIV-3. Recovered virus was neutralized by anti-HPIV-3 antisera and shown to contain specific base substitutions characteristic of pHPIV-3. Recombination was shown to occur during recovery, as viruses with two distinct genotypes and phenotypes were isolated. The ability to produce infectious HPIV-3 engineered to contain specific alterations within the HPIV-3 genes and cis-acting elements expedites the study of all aspects of the virus replication cycle. Additionally, analysis of mutations may lead to the identification of attenuating genotypes, a key step in the development of a live virus vaccine.

Cloning, Molecular↗
PubMed1997

Pulmonary capillary haemangiomatosis as a cause of pulmonary hypertension in Takayasu's aortoarteritis.

Pulmonary hypertension is known to occur in Takayasu's aortoarteritis. It may be either due to pulmonary arterial involvement or elevated left ventricular end diastolic pressure, or both. In our case, the cause of pulmonary hypertension was a recently described rare lesion termed pulmonary capillary haemangiomatosis. This entity has a very distinct histopathologic picture. Although 19 cases have been reported in the English literature, this is the first report on pulmonary capillary haemangiomatosis producing pulmonary hypertension in Takayasu's aortoarteritis.

Child↗
PubMed1997

Intravenous contrast media: are they being administered safely in radiology departments?

A recent Royal College of Radiologists (RCR) publication is entitled Advice on The Management of Reactions to Intravenous Contrast Media. This study aims to determine whether radiology departments are adhering to the essential points, covered in the guidelines, regarding prevention, early recognition and prompt treatment of adverse reactions, and whether they are adequately equipped for the proposed contrast media reaction management protocols. A questionnaire was formulated and sent to the superintendent radiographers of 295 radiology departments in the United Kingdom of whom 233 (79%) replied. This was specifically directed at the use of intravenous contrast media in intravenous urography. In almost all departments there was provision for basic life support training, regular checking of equipment and drugs, and prompt access to emergency medical help. Certain "first line" drugs and monitoring equipment were not instantly accessible in the majority of institutions. Most departments did not adequately supervise post-injection patients and did not conform to the guidelines referring to the administration of intravenous contrast to children. Certain areas of the guidelines are being neglected by many radiology departments and there is still much to be done to improve the safety of intravenous contrast medium injection.

Contrast Media↗
PubMed1997

T cell rich and histiocyte rich B cell lymphoma--a case report.

We report one case of Non Hodgkin's Lymphoma which was classified as Histiocyte Rich B cell lymphoma on immunocytochemistry. The diagnosis was difficult on fine needle aspiration cytology and routine histopathological examination as the infiltrate was composed of reactive lymphocytes and numerous histiocytes obscuring the lymphoma cell population. The neoplastic cells were positive for CD20(L26-A Pan B marker) and negative for CD15(Leu M1), CD3(Ber H2) and pan T cell markers. The histiocytes were positive for CD3(UCHL-1). The patient had a rapid downhill course and died. The autopsy showed infiltration in the axillary, cervical, mesenteric, para aortic, peri pancreatic and hilar lymph nodes. The liver, spleen, bone marrow and kidney also showed lymphomatous infiltration.

Adult↗
PubMed1997

Role of cellular kinases in the gene expression of nonsegmented negative strand RNA viruses.

Nonsegmented negative strand RNA viruses package an RNA-dependent RNA polymerase composed of two subunits, a large protein L and a phosphoprotein P, for transcription and replication of their genome RNAs. The RNA polymerase activity resides within the L protein, while the P protein acts as a transcription factor or transactivator of the polymerase. Since P protein is heavily phosphorylated and phosphorylation is known to regulate function of many viral as well as cellular proteins, the role of phosphorylation of P protein in the gene expression of this group of RNA viruses has recently been investigated. Through expression in bacteria the P protein was produced in large quantity in the nonphosphorylated form and involvement of cellular kinase(s) in its phosphorylation was studied. Casein kinase II and/or protein kinase C have been shown to play a critical role in the activation of P protein in transcription. These findings have opened up a new avenue for studying an important regulatory step in virus gene expression that may lead to the development of an effective antiviral agent.

Animals↗
PubMed1997

Display of disparate transcription phenotype by the phosphorylation negative P protein mutants of vesicular stomatitis virus, Indiana serotype, expressed in E. coli and eucaryotic cells.

The phosphoprotein (P) of vesicular stomatitis virus (VSV) is a subunit of the RNA polymerase (L) that transcribes the negative strand genome RNA into mRNAs both in vitro and in vivo. We have recently shown that the P protein of VSV, New Jersey serotype (PNJ), expressed in E. coli, is biologically inactive unless phosphorylated at specific serine residues by cellular casein kinase II (CKII). In the present work, we are studying the role of phosphorylation in the activation of the P protein of Indiana serotype (PIND), which is highly nonhomologous in amino acid sequence yet structurally similar to its New Jersey counterpart. Despite the fact that E. coli-expressed PIND required phosphorylation by CKII for activation, the phosphorylation negative P protein mutants generated by altering the phosphate acceptors S and T to alanine, surprisingly, showed transcription activity similar to wild-type in vitro. Alteration of S and T residues to phenylalanine, similarly, supported substantial transcription activity (approx. 60% of wild-type), whereas substitution with arginine residue abrogated transcription (approx. 5% of wild-type). In contrast, the same mutants, when expressed in eucaryotic cells, exhibited greatly reduced transcription activity in vitro. This disparate display of transcription phenotype by the PIND mutants expressed in bacteria and eucaryotic cells suggests that these mutants are unique in assuming different secondary structure or conformation when synthesized in two different cellular milieu. The findings that, unless phosphorylated by CKII, the bacterially expressed unphosphorylated (P0) form of PIND, as well as the phosphorylation negative mutants expressed in eucaryotic cells, demonstrates transcription negative phenotype indicate that, like PNJ, phosphorylation of PIND is essential for its activity.

Animals↗
PubMed1996

Specific interaction in vitro and in vivo of glyceraldehyde-3-phosphate dehydrogenase and LA protein with cis-acting RNAs of human parainfluenza virus type 3.

Human parainfluenza virus type 3 (HPIV3) genome RNA is transcribed and replicated by the virus-encoded RNA-dependent RNA polymerase, and specific cellular proteins play a regulatory role in these processes. To search for cellular proteins potentially interacting with HPIV3 cis-acting regulatory RNAs, a gel mobility shift assay was used. Two cellular proteins specifically interacted with the viral cis-acting RNAs containing the genomic 3'-noncoding region and the plus-sense leader sequence region. Surprisingly, by biochemical and immunological analyses, one of the cellular proteins was identified as the key glycolytic enzyme, glyceraldehyde-3-phosphate dehydrogenase (GAPDH). The other protein was characterized as the autoantigen, LA protein. Both GAPDH and LA protein also interacted with the same cis-acting RNA sequences in vivo and were found to be associated with the HPIV3 ribonucleoprotein complex in the infected cells. By double immunofluorescent labeling, GAPDH was found to be co-localized with viral ribonucleoprotein in the perinuclear region. These observations strongly suggest that cellular GAPDH and LA Protein participate in the regulation of HPIV3 gene expression.

Autoantigens↗
PubMed1996

Digoxin therapy and survival in heart failure in sinus rhythm.

The effect of digoxin therapy on the survival of heart failure patients in sinus rhythm was assessed using a retrospective case control study. Patients with an acute exacerbation of chronic heart failure secondary to ischemic heart disease were selected. All were in sinus rhythm and all were treated with digoxin. Case-matched controls were identified for all digoxin-treated patients. Long-term survival was ascertained for all 18 digoxin-treated patients and 18 controls who formed the study population. The relative risk of death was 6.4 for digoxin-treated patients (95% confidence interval 0-36) during the period of hospitalization. Te increased risk of death among digoxin-treated patients persisted up to 1 year following discharge from hospital. The results raise further concern regarding the safety of digoxin therapy in managing heart failure exacerbation, when the patients are in sinus rhythm.

Administration, Oral↗
PubMed1996

Inhibition of human parainfluenza virus-3 replication by interferon and human MxA.

We have investigated the IFN-mediated inhibition of human parainfluenza virus-3 (HPIV-3) replication in cultured human A549 cells. IFN-alpha inhibited the virus yield significantly with concomitant reduction of viral RNA accumulation by more than 90%. Further studies indicated that the inhibitory action of IFN was at the level of primary transcription of HPIV3 replication. Since the IFN-inducible protein, MxA, has been shown to inhibit virus replication in several RNA viruses, we examined the role of MxA in HPIV-3 replication using a stably transfected human glioblastoma cell line expressing MxA. In these cells HPIV-3 replication was decreased by more than 100-fold depending on the virus dosage used with concomitant inhibition of viral RNA synthesis by about 80%. However, the viral primary transcription was not affected in this MxA-producing cell line. In contrast, in the parental cell line IFN-mediated inhibition occurred at the primary transcription step of HPIV-3 replication. These data suggest that in addition to MxA, other IFN-inducible proteins are involved in the anti-HPIV-3 effect of IFN in both the cell lines used.

Antiviral Agents↗
PubMed1996

Expression of the human MxA protein is associated with hyperphosphorylation of VSV P protein in human neural Cells.

Constitutive expression of the type I interferon-inducible human cytoplasmic MxA protein has been shown to interfere with primary transcription of vesicular stomatitis virus (VSV) in tissue culture cells. As phosphorylation of the VSV P protein has been linked to its ability to stimulate viral transcription, we analyzed the phosphorylation status of this protein in human brain cells (U-87) stably transfected with MxA. We observed a general increase in cellular kinase activity in the presence of MxA, affecting both cellular proteins and VSV P protein. Phosphorylation of the latter was up to threefold higher both in vivo and in vitro. In vitro phosphorylation of recombinant VSV P protein could be enhanced in MxA-negative cell extracts after exogenous addition of recombinant His-MxA. Biochemical evidence and phosphorylation of a mutant P protein lacking the recognized casein kinase II (CKII) sites suggested that hyperphosphorylation of VSV P protein was not due to a stimulation of CKII. We thus propose that expression of MxA in human brain cells is associated with the stimulation of a cellular kinase that is active in phosphorylating both cellular target proteins and VSV P protein.

Casein Kinase II↗
PubMed1996

Improving cancer radiotherapy with 2-deoxy-D-glucose: phase I/II clinical trials on human cerebral gliomas.

PURPOSE: Evaluation of tolerance, toxicity, and feasibility of combining large fraction (5 Gy) radiotherapy with 2-deoxy-D-glucose (2DG), an inhibitor of glucose transport and glycolysis, which has been shown to differentially inhibit repair of radiation damage in cancer cells. METHODS AND MATERIALS: Twenty patients with supratentorial glioma (Grade 3/4), following surgery were treated with four weekly fractions of oral 2DG (200 mg/kg body weight) followed by whole brain irradiation (5 Gy). Two weeks later, supplement focal radiation to the tumor (14 Gy/7 fractions) was given. Routine clinical evaluation, x-ray computerized tomography (CT), and magnetic resonance (MR) imaging were carried out to study the acute and late radiation effects. RESULTS: All the 20 patients completed the treatment without any interruption. The vital parameters were within normal limits during the treatment. None reported headache during the treatment. Mild to moderate nausea and vomiting were observed during the days of combined therapy (2DG + RT) in 10 patients. No significant deterioration of the neurological status was observed during the treatment period. Seven patients were alive at 63, 43, 36, 28, 27, 19, and 18 months of follow-up. In these patients, the clinical and MR imaging studies did not reveal any late radiation effects. CONCLUSIONS: Feasibility of administering the treatment (2DG + 5 Gy) is demonstrated by the excellent tolerance observed in all 20 patients. Further, the clinical and MR studies also show the absence of any brain parenchymal damage.

Adult↗