A new cell line from larval ovaries of Spodoptera litura (F.) (Lepidoptera:Noctuidae)
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Biomedical subjects
Publications and source records attributed to K Banerjee.
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In the South-East Asia Region (SEAR) of WHO, paralytic poliomyelitis has decreased from 25,711 cases in 1988 to 3304 cases in 1995, representing an 87% reduction. By 1995, in 6 of 10 member countries--India, Bangladesh, Myanmar, Nepal, Indonesia, and Democratic People's Republic of Korea--polio remained endemic. Two countries, Sri Lanka and Thailand, appear close to polio eradication, and 2, Bhutan and Maldives, reported no cases during 1989-1995. Although reported rates of acute flaccid paralysis and the percentage of cases virologically investigated are low in some countries, no isolates of wild poliovirus type 2 have been reported outside India since 1993. By the end of 1996, all 8 countries in which polio is endemic will have conducted national immunization days for polio eradication. The major challenge for polio eradication in SEAR will be strengthening surveillance, because national immunization days alone cannot eradicate polio.
Out of the 15 hepatitis E (HEV) epidemics that occurred during the years 1976-1995 in the Gujarat and Maharashtra states of India, 45.78% (76/166) stool samples showed the presence of HEV RNA. HEV RNA was found significantly more often in samples that were transported in liquid nitrogen (50.9%) compared with samples that were transported in wet ice (37.0%) (P < 0.05). Stool samples collected within 7 days after the onset of the disease (59.2%) were more often positive for HEV RNA when compared with samples that were collected 7-20 days after the onset of the disease (28.5%) (P < 0.01). It has been observed in experimentally infected Rhesus monkeys that they excrete HEV throughout the incubation period and for a variable length of time after the elevation of serum ALT levels. A similar situation is found in humans.
B cell growth and differentiation into immunoglobulin secreting cells is controlled by various cytokines and cell to cell contact with T cells. Fusion partner for human hybridoma therefore should accommodate all or some of these signaling systems to overcome the unique situation of MHC incompatibility, need for specific growth factors simultaneously taking into consideration the downstream processing of the product for the clinical use. We have thus directed our efforts towards the development of a fusion partner which would not need Epstein-Barr virus transformation of B cells prior to fusion. A nontransforming mitogen, formalinized Staphylococcus aureus (FSTA) was used for stimulating human B cells. Successful production of human IgM monoclonal antibody was achieved by incorporating Jurkat-4 cells in existing mouse human heterohybrid through fusion of these cells followed by fusion with human B cells. To accommodate chromosomes of both T and B cells after fusion, human myeloid precursor cells KG1a, and to incorporate T cell, HuT78 cells were fused. CD34+ and CD4+ hybrid of KG1a and HuT 78 cells-434 AM-when used as fusion partner could allow secretion of MAbs, however growth potential was low. SP2/0 cells were then incorporated in 434 AM cells to give myeloma environment to fused human B cells. Rabies virus neutralizing human IgG MAb secreting clone was generated by fusing FSTA stimulated human B cells with this fusion partner.
Repeated outbreaks of a suspected viral fever in Chirimiri colliery area, Madhya Pradesh were reported since 1990. The area consists of an agglomeration of sprawling settlements at varying altitudes of 816 to 890 m and it has partial sylvan cover. During a 1992 outbreak 25 patients' sera were tested, of which 13 showed seropositivity to dengue (DEN) by MAC-ELISA test; DEN-2 was isolated from Aedes aegypti collected from two of the eight settlements of the area. The principal vector, Ae. aegypti, was prevalent in all the settlements studied; Breteau indices (BI) varied between 2.5 and 125.0; adult house indices (AHI) between 0 and 60.0%; Ae. albopictus and Ae. vittatus occurred in considerable numbers; Ae. aegypti bred in more containers with nonpotable water than those with potable water; the breeding of this species was noted in a maximum number of cement tanks while mud pots were predominant among the available containers. Paired comparisons between relative prevalence indices showed significant correlation and regression coefficients. Significant association of Ae. aegypti breeding with the households having tap water supply was noted, the relative risk declining with the people's use of well water either exclusively or in combination with other sources of water supply. It was also collected in the nonresidential areas. The role of ecological factors in the maintenance and spread of Ae. aegypti and dengue in these settlements is discussed.
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Experimental studies were carried out to determine the vector potential of four species of mosquitoes to West Nile (WN) virus, viz. Culex tritaeniorhynchus, Cx. vishnui, Cx. bitaeniorhynchus and Cx. univittatus. All the four species of mosquitoes successfully transmitted and supported the growth of WN virus. The study indicated that the four species of mosquitoes could act as potential vectors of WN virus in nature.
The potency of vaccines against Japanese encephalitis (JE) is usually determined by a mouse challenge test. In the present study, an antigen capture enzyme-linked immunosorbent assay (ELISA) using monoclonal antibodies (MoAbs) was used to screen inactivated tissue culture JE vaccine lots. This test is simple, quick and reliable besides being very sensitive and specific.
During 1992-96, outbreaks of buffalopox zoonosis were reported from different villages in Jalgaon, Dhule and Beed districts of Maharashtra State. In humans, pox lesions were observed on the hands whereas in affected buffaloes and cows the lesions were noticed mainly on the teats and udder. Twenty two virus strains were isolated from the skin scabs collected from infected humans and milch animals. Neutralizing antibodies were detected not only in the sera of affected humans but also in their contacts. Detection of antibodies in young individuals from endemic area, who were neither vaccinated for smallpox nor had any contact with buffaloes or history of any poxvirus disease, is suggestive of occurrence of subclinical infection. A few children who had no contact with infected animals also showed clinical manifestations with disseminated lesions on the face, arm and buttocks, and thus suspected to have acquired infection through their infected parents or other family members indicating a possible man to man transmission. Therefore, in the light of discontinuation of smallpox vaccination, buffalopox outbreaks need to be monitored carefully as this may emerge as a serious zoonotic disease in India.
Variation among Japanese encephalitis virus (JEV) strains has been documented in a number of studies by employing a variety of techniques like HI, NT, CF, RNA fingerprinting and sequencing of prM region. We report the complete envelope (E) gene sequence and the deduced amino acid sequence of four strains of JEV from the Indian subcontinent. These sequences were compared with published E gene sequences of 16 strains of JEV. Pairwise comparisons of the E gene nucleotide and deduced amino acid sequences of these strains indicated an overall sequence conservation. A majority of the differences in the four strains were located in domain A and domain C (Mandl et al., 1989). Phylogenetic analysis of the E gene sequences by a variety of tree building methods identified four clusters. Viral groupings did not correspond to geographic origin, isolation host or virulence. Evidence for positive selection operating on some strains belonging to different clusters was obtained.
BACKGROUND/AIMS: Interferon therapy has been shown to be effective in Western patients with chronic hepatitis due to hepatitis B viral infection, but not in Asian Chinese. Its efficacy in Asian Indian subjects with chronic HBV infection is not known. METHODS: Forty-one patients with HBV-related chronic liver disease received randomly either: (a) recombinant alpha 2b interferon (n = 20) 3 MIU, subcutaneously, three times a week for 4 months, or (b) no treatment (n = 21). Patients were followed up for 12 months after completion of therapy. RESULTS: In the interferon-treated group, complete response (loss of HBV-DNA and HBeAg) was significantly higher than spontaneous clearance in the control group (50% vs. 4.8% p < 0.05). Seroconversion to anti-HBe was seen in 35% of the treated and 4.8% of the control group (p < 0.05) at 4 months; it was noticeably higher in patients with chronic hepatitis than in those with cirrhosis. In the responders, alanine aminotransferase levels nearly normalized. One year after interferon therapy, HBeAg and HBV-DNA clearance was observed in 65% of patients, with HBsAg clearance in 15%. Reactivation was not seen in any patient. Side-effects were transient and minimal. CONCLUSION: Low-dose recombinant alpha interferon therapy is quite effective and safe in Asian Indians with chronic liver disease due to hepatitis B infection.
BACKGROUND/AIMS: Post-transfusion hepatitis continues to occur, though with decreasing frequency, even after screening donor blood for HBsAg, anti-HBc, anti-HCV and alanine aminotransferase activity. Data from developing countries on the frequency and type of post-transfusion hepatitis are scarce. We undertook this prospective study to determine the incidence and type of post-transfusion hepatitis at our center after transfusion of blood negative for HBsAg by ELISA. METHODS: Forty-one patients undergoing open-heart surgery, who had received 3 or more units of HBsAg-negative blood, were followed up. Serum samples of donor units transfused to recipients who developed post-transfusion hepatitis-B were subjected to HBV DNA amplification by the polymerase chain reaction, using two sets of X-gene specific primers which amplified a 250-bp fragment of the HBV DNA. RESULTS: We found that six of the 41 patients (14.6%) developed post-transfusion hepatitis; four of them (66.6%) developed icteric post-transfusion hepatitis B, whereas two (33.3%) developed anicteric post-transfusion hepatitis C. These six recipients received a total of 48 units of blood and 30 of these 48 units could be subjected to HBV DNA amplification by polymerase chain reaction. Eleven donor samples were polymerase chain reaction positive and had been transfused to three of the four patients who had developed post-transfusion hepatitis B. CONCLUSIONS: We conclude that post-transfusion hepatitis B continues to be the most common cause of post-transfusion hepatitis in India. Screening of donor units for HBsAg by ELISA does not exclude all blood units infectious for hepatitis B virus. Additional measures to ensure safety of blood supply should be sought.
ISCOMs (immunostimulating complexes) were prepared from envelope glycoprotein (Egp) of Japanese encephalitis (JE) virus. ISCOMs showed a single band of the viral Egp in SDS-PAGE, which reacted with polyclonal and monoclonal antibody (MAb) raised against Egp. Comparison between the epitopes exposed on JE virion and JE ISCOMs, by antigen capture ELISA, utilizing a panel of domain-specific MAbs, revealed identical epitopes exposed on the Egp incorporated in ISCOMs and the whole virion. Electron micrographs of ISCOMs showed spherical cage-like structures of 35 nm. ISCOMs with Egp were good immunogenes, which stimulated high titres of neutralizing antibodies, both in mice and rabbits.
A cell line (MRK-90) has been established from a kidney tissue of a macaque monkey (Macaca radiata) of India. The cells are in 150th passage and have been characterized for morphology, chromosome number, isoenzyme patterns (LDH and MDH) and virus susceptibility. These studies indicate that the cells are epithelial like, heteroploid (2n = 65) and grow easily on glass surface/plastic surface without any difficulty. The cells are susceptible to a broad spectrum of viruses.
BACKGROUND: Infection due to hepatitis B virus (HBV) could be due to wild or mutant (precore or surface) viruses. The prevalence and clinical profile of different viral forms in patients with chronic liver disease has not been established. METHODS: One hundred and twenty patients with histologically proven HBV-related chronic liver disease were studied. Patients with dual infection with HCV/HDV/HIV, past history of interferon therapy, or autoimmune hepatitis were excluded. Eighteen (15.5%) patients had the precore mutation (HBsAg +ve, HBeAg -ve/anti-HBe +ve, HBV DNA +ve), and 13 (10.8%) had the surface gene mutations (HBsAg -ve, HBeAg -ve, IgG anti-HBc, and HBV DNA +ve). The remaining 89 (74.2%) patients were infected with wild type HBV. The course of all patients with mutant forms and 41 of those with the wild type form was followed for a mean (+/- SD) of 4.4 +/- 2.4 yr. RESULTS: Compared with wild-type-infected patients, those with surface mutation were younger (39.9 +/- 14 vs. 30.1 +/- 12.4 yr, p < 0.05). Patients with precore mutations had a shorter illness than those with surface mutant (p < 0.01) and wild forms (p < 0.05). Histologically, patients with precore type had more active liver disease than wild type (39% vs. 15%, p < 0.05). Patients with precore mutations were always symptomatic, often presenting with ascites (67%) and jaundice (55%). Patients with surface mutant forms often presented with quiescent cirrhosis (77%) or cirrhosis with hepatoma (15%). CONCLUSIONS: One-fourth of HBV-related chronic liver disease in Asian Indians is attributable to mutant HBV forms. The presence of variant viruses alters the natural history of the disease, with the precore variance having a more aggressive course and the surface mutant, a more quiescent but unfavorable course, compared with the wild type.
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An emerging viral infection may be a totally new disease with undescribed symptomatology as it was in the case of Kyasanur forest disease in Karnataka, but more often it is an introduction of a known or little known disease in an area where the disease did not occur earlier e.g. yellow fever in Kenya or Rift valley fever in Egypt. The virus may show altered degree of virulence due to many changing factors as in the case of the different haemorrhagic fevers. Many factors may contribute to the emergence of viral infections which may be genetic exchanges or mutations; adaptation to new hosts or vectors; and changed social patterns of humans like urbanization, rapid transport, trade, migration of people or of vectors, strain on civic facilities or changing moral values and life-styles. Large scale changes in ecology due to global warming, deforestation or afforestation, building of dams or canals, changed agricultural practices, rearing of livestock or birds may also contribute to emergence of viral diseases. A number of emergent virus infections relatively important to India have been discussed. To combat emergent virus infections, a comprehensive strategy needs to be evolved. A national viral surveillance system needs to be established. Epidemiology of virus diseases needs to be studied in depth. Development of diagnostic reagents and their supply to investigating centres, a Central serum bank, and a virus respository are important factors. Research and development on viruses, as regards the epidemiology, diagnosis, pathogenesis and vaccinology of virus infections need to be strengthened. An international network of databases of virus infections needs to be instituted. A global network for the diagnosis and containment of emerging viral diseases is advocated.
Thirty-seven serum samples and five serum-CSF pairs collected from 42 acutely ill patients admitted to hospitals in Maharashtra (Bombay, Pune and Nasik); Orissa (Raurkela) and South Goa were referred to the National Institute of Virology (NIV), Pune (Maharashtra, India) for serodiagnosis. These patients had clinical manifestations of fever, hemorrhagic manifestations, hepatomegaly, shock syndrome and encephalopathy. Sixty-six percent of patients were children below ten years of age. Serological investigations revealed infection to dengue virus in all the patients as indicated in detection of IgM antibodies predominantly to dengue viral antigens. An important outcome of the study is that 10 patients referred to NIV with a provisional diagnosis of viral encephalitis proved to be dengue.