Biomedical subjects
Publications and source records attributed to A K Banerjee.
A 46 year old woman presented with the CREST variety of systemic sclerosis and occult gastrointestinal bleeding due to vascular malformations of her stomach. Partial gastrectomy cured her anaemia. In systemic sclerosis, visceral angiography should be performed early when initial investigations have been negative.
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There have been recent reports of enhancement of the inner ear in acute labyrinthitis on gadolinium enhanced magnetic resonance imaging (MRI). However, none has described persistence of enhancement beyond 6 weeks. We report a case of Ramsay Hunt syndrome with labyrinthitis, sensorineural hearing loss and facial nerve palsy in which marked enhancement of the inner ear structures was observed on MRI 6 months after the onset of symptoms. Enhancement on delayed or repeated imaging after a period of months does not exclude labyrinthitis from the differential diagnosis of the small intracanalicular acoustic neuroma, and care should be taken not to confuse them.
Immunohistochemical analysis of 9 choroid plexus papillomas (CPPs) and 3 choroid plexus carcinomas (CPCs) using a panel of antibodies against glial fibrillary acidic protein (GFAP), cytokeratin (CK), epithelial membrane antigen (EMA), S-100 protein, vimentin (vim), and neuron specific enolase (NSE) is presented. Focal positivity was observed for GFAP in 11, vimentin in 7, cytokeratin in 2 and EMA in 3 cases. Diffuse and intense immunoreactivity for S-100 protein was seen in all papillomas, however, unreactive areas were noted in carcinomas. All cases exhibited focal to diffuse NSE positivity. Location and type of the tumour and age of the patient did not influence the staining pattern except for predominant S-100 positivity in papillomas. The significance of these findings is discussed in relation to the differential diagnosis or immunoreactivity patterns of these tumours.
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A retrospective study on pattern of malignant lesions in a rural district of West Bengal from 1981-1990 was conducted in the department of pathology, BS Medical College, Bankura, West Bengal. A total number of 17,130 cases were received out of which 1976 were malignant lesions (11.53%). The peak incidence of cancer in both sexes was found between the 4th, 5th and 6th decades, ie, 31-60 years of age. Sex-wise distribution showed more incidence in female (1246-62.17%) than in male (730-37.83%). Cancer of the cervix (35.62%) showed the highest incidence in this series. Cancer of the larynx (11.94%) was the commonest cancer in males. Malignancy of the lymph node was observed in 11.43% cases. Malignancy of the lungs and vagina (< 0.5%) showed very low incidence.
We report a simple and effective technique for vasovasostomy. Over 105 procedures have been performed over a 10-year period by a single consultant and his registrars with results comparable to those obtained with more time-consuming formal microsurgical techniques when routine luminal dilatation of the vas was adopted. Additionally, the chances of success were found to be greater the shorter the interval between vasectomy and vasovasostomy.
Isoxazole derivatives have been shown to possess antiparasitic activity. In the present study, 3-substituted 5-methylthio-isoxazoles were synthesized and tested for anthelmintic activity, along with some other isoxazoles which have been reported but not tested earlier. Nine compounds (2a, 2b, 2e, 2g, 2u, 3a, 3b, 3e and 3f) showed activity against both A. ceylanicum and N. dubius in vitro. Twelve compounds (2a, 2b, 2d, 2e, 2f, 2h, 2l, 2n, 2o, 2u, 3d and 3e) showed activity against N. dubius in vivo, a parasite of veterinary importance.
A retrospective analysis of 40 patients with pleural effusions caused by breast cancer is presented. Evidence is presented which suggests that malignant pleural effusion in breast cancer is caused by lymphatic rather than blood spread. 70% of effusions are ipsilateral to the primary carcinoma and 22.5% of patients with pleural effusions have positive internal mammary node biopsies (compared to 10.4% in controls). 47.5% of effusions had positive cytology but this does not correlate with either survival or recurrence. In operable tumours, pleural effusion is correlated with the size of the primary tumour but effusions were uncommon with large, locally advanced Stage III tumours at presentation, which could be attributable either to the short survival of such patients or to the effect of adjuvant radiotherapy reducing the chance of an ipsilateral effusion. Although these patients overall had a short life expectancy (median 11 months) there was a wide range. Chest drainage and instillation of 100 mg mepacrine in 30 ml of bupivacaine to give rise to pleurodesis offers useful palliation and minimizes recurrence (29 treatments with only two symptomatic recurrences), compared with aspiration alone (19 treatments with 12 symptomatic recurrences) or instillation with tetracycline (10 treatments with five symptomatic recurrences). Pleural effusion secondary to breast cancer is a locoregional manifestation. Pleurodesis with mepacrine offers good local control.
Specific interaction between the nucleocapsid protein (N) and the phosphoprotein (P) of vesicular stomatitis virus (VSV), an important step in the life-cycle of the virus, was studied by using a two-hybrid system. Plasmids encoding P fused with the yeast GAL4 DNA-binding domain (pGALP) and N fused with the herpes simplex virus VP16 transactivating region (pVPN) were transfected into CHO cells along with a reporter plasmid encoding chloramphenicol acetyltransferase (CAT). The ability of N and P to associate in vivo was measured by activation of the CAT gene by the VP16 transactivating region. Transfection of plasmids pGALP and pVPN resulted in a high level of CAT activity, indicating that the N and P portions of the fusion proteins associated very strongly with each other. Progressive C-terminal deletions of the P protein revealed two regions that are important for association with the N protein: the N-terminal acidic domain and the C-terminal basic domain. Phosphorylation of P protein was not required for N-P association. Various deletions and mutations of the N protein revealed the C-terminal 5 amino acids (Val-Glu-Phe-Asp-Lys), in particular the amino acids Val-Glu-Phe, to be critical for N association with P. This two-hybrid system can be used in other viral systems to study the interaction between proteins involved in transcription and replication.
The transcribing ribonucleoprotein (RNP) complex of human parainfluenza virus type 3 (HPIV-3) requires cellular actin for transcription of viral genome in vitro (De, B. P., Lesoon, A., and Banerjee, A. K. (1991) J. Virol. 65, 3268-3275). In this communication, we have studied the interactions between different molecular forms of actin and the RNP of HPIV-3 to understand the role of actin in mRNA synthesis. We demonstrate that both polymeric and monomeric forms of actin (obtained by DNase I treatment) bind strongly to the RNP at 100 mM KCl concentration (polymerizing buffer). The binding was virtually abolished at zero KCl concentration (depolymerizing buffer). Isolation of the RNP-actin complex and subsequent use in a transcription reaction showed that the bound actin alone was sufficient for mRNA synthesis in vitro. Interestingly, the DNase I-arrested monomeric form of actin failed to activate mRNA synthesis, indicating a requirement of polymerization of the bound actin during HPIV-3 transcription. Electron microscopic analyses revealed that a drastic structural modification of the RNP occurred because of the polymerization of actin from a loosely coiled and irregular structure to a condensed and flexible structure. Activation of transcription was observed also with poly-L-glutamic acid, a highly acidic polypeptide. However, unlike cellular actin, poly-L glutamic acid was able to activate only 10% of the input RNP. These results suggest that cellular actin activates HPIV-3 transcription by polymerizing specifically on the RNP complex. This event results in an alteration of the RNP structure that enhances its suitability for efficient transcription. The acidic domain of actin may play an important role in this process.
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Vesicular stomatitis is a viral disease of cattle, pigs, and horses. The disease is characterized by vesicular lesions on the epithelium of the mouth, feet, and teats. The pathological lesions are virtually indistinguishable from that of foot-and-mouth disease. We have developed a recombinant baculovirus that expresses the nucleocapsid (N) protein of the New Jersey serotype of vesicular stomatitis virus (VSVNJ) in insect cells (Sf9) and larvae (Spodoptera exigua). The gene was expressed under control of the polyhedrin promoter as a fusion or nonfusion protein. The recombinant N protein expressed in insect cells could not be distinguished from N protein produced in VSVNJ-infected CHO cells by immunological and biochemical analyses. The level of expression of N as a percentage of the total protein in Sf9 cells was 41% for the fusion and 60% for the nonfusion protein. Higher level (68%) of expression of the nonfusion N protein was obtained in larvae. Recombinant N protein was used in an ELISA to distinguish animals vaccinated with a recombinant VSV glycoprotein from those exposed to the whole virus by infection or classical vaccine. Lysate of a single infected larva (0.2-0.3 g) was adequate for coating ELISA plates to perform 10,000 serum assays in duplicate.
The nucleocapsid (N) protein genes of vesicular stomatitis virus, serotypes New Jersey and Indiana, were expressed in Escherichia coli BL21(DE3) transformed by the recombinant expression vector pET-3a containing N genes under the control of the T7 RNA polymerase promoter. Following induction with isopropylthiogalactopyranoside, the N protein was synthesized, representing 10 to 20% of total cellular protein. The N protein remained in a nonaggregated form in 1 M NaCl solution. The purified N protein was found to be biologically active as demonstrated by its encapsidation of preformed leader RNA as well as its synthesis of genome length RNA in an in vitro transcription-replication reaction. The availability of recombinant N protein in a sufficient amount would facilitate structure and function studies of this important viral protein.
An in vitro transcription system for human respiratory syncytial virus (RSV) is described. Purified viral nucleocapsid (RNP) isolated from virus-infected cells was shown to support transcription of all 10 genes encoded by the virus as determined by Northern blot hybridization. The mRNAs synthesized were polyadenylated and comigrated with the corresponding mRNAs synthesized in virus-infected cells when analyzed in agarose-urea gel electrophoresis. The in vitro-synthesized mRNAs are functional as determined by their capacity to synthesize protein in vitro. The transcriptional reaction was significantly stimulated by the uninfected host cell lysate, indicating a requirement of host factor(s) in mRNA synthesis. Preliminary results suggest that cellular actin is involved in this process.
A simple system that allows expression and packaging of a foreign gene by human parainfluenza virus type 3 (HPIV-3) has been described. First, a cDNA was constructed to encode an internally deleted version of HPIV-3 genome RNA. The viral genes were replaced with a negative sense copy of the bacterial chloramphenicol acetyl transferase (CAT) reporter gene. In vitro run-off transcription with T7 RNA polymerase synthesized an 870 nucleotide RNA that contained the antisense coding region of the CAT gene flanked by the transcription regulatory sequences and the 3' and 5' end extracistronic sequences of the HPIV-3 genome. When introduced into cells that are infected with HPIV-3, this RNA was amplified and the reporter gene was expressed, as measured by the CAT activity in the cell extract. Furthermore, the synthetic RNA was packaged into infectious virions. The addition of two extra nucleotides at the 5' end of the parental trailer region decreased the CAT activity by more than 90%, suggesting a requirement for the intact 5'-regulatory domain in the viral replicative cycle. Interestingly, the addition of one extra nucleotide to the 3' end totally abolished the CAT activity indicating that an exact 3' terminus is critical in this process.
The protocols of 1,000 consecutive adult patients autopsied during the period June 1983 to December 1988 were retrospectively analyzed and the findings were compared with clinical diagnoses. The autopsy rates during this period ranged between 23% and 27% of hospital deaths. Eighty-seven percent of the autopsied patients were between 15 and 59 years of age. Major discrepancies between the autopsy reports and the clinical diagnoses were present in 31.7% of all autopsy reports reviewed. Infectious diseases were the most common cause of death (46.8%), followed by cardiovascular diseases (17.1%) and neoplastic diseases (14.3%). Infections were clinically recognized in 66.7% of cases and were missed or found to be incorrect in 33.3% of cases. Tuberculosis comprised 33.8% of the major bacterial infections and was clinically diagnosed in 82% of cases. Eighty-nine percent of the major fungal infections were not suspected clinically. Rheumatic heart disease (43.8%) was the most common cardiovascular disorder and was clinically diagnosed in 93.3% of cases. Pulmonary vascular episodes were the least common cause of death and were not suspected clinically in 62.9% of cases. Malignancies were incorrectly diagnosed in 25.8% of cases. We conclude from this study that routine autopsies revealed major unexpected findings that are of clinical importance, and that a continued emphasis on autopsy evaluation is necessary for the improvement of the quality of patient care.
The importance of coronary collateral circulation in relation to the left ventricular function, aneurysm formation and size was investigated in 100 patients with previous 'Q' wave myocardial infarction who underwent coronary angiography. Aneurysms were present in 20% of patients. The majority of these (80%) patients had severe or total occlusion of the left anterior descending artery. Thirty four percent of patients without aneurysm had significant collaterals whereas 25% of patients with aneurysms had collaterals (P > 0.05). However, the size of the aneurysm was smaller when adequate collateral circulation was present (Collateral Index 2 or above). The incidence of hypertension and diabetes was similar in both groups. Collateral circulation was more frequently seen in the anterior (60%) as compared to inferior myocardial infarction (40%), but Collateral Index was higher in right coronary artery disease. The number of patients with an elevated left ventricular end-diastolic pressure (> 12) or poor ejection fraction was similar in the two groups with and without collaterals. Thus, there was no beneficial effect of collateral circulation on left ventricular function. The incidence of aneurysm was not significantly lower, although the size of the aneurysm was significantly smaller in the presence of collateral circulation.