Biomedical subjects

K Banerjee

Publications and source records attributed to K Banerjee.

262 records · Page 15Linked to original sources

PubMedDate not supplied

Near-field optical studies of local photomodification in nanostructured materials.

Fractal aggregates of silver nanoparticles are studied experimentally using atomic force microscopy and photon scanning tunnelling microscopy. Large changes in the near-field optical response of fractal aggregates are observed after the irradiation of samples with nanosecond laser pulses. The threshold energy density for photomodification using a 532 nm laser is measured to be 9 mJ cm(-2). It is shown that photomodification-induced changes in the local optical response can be two orders of magnitude larger than changes in far-field absorption.

Journal Article↗

PubMedDate not supplied

Detection of human immunodeficiency virus antibody among homosexual men from Bombay.

BACKGROUND AND OBJECTIVES: In India, heterosexual transmission of HIV-infection is considered to be the major mode of transmission. However, no report is available on transmission of HIV-infection among homosexually active men. The prevalence of human immunodeficiency virus-1 (HIV-1) and human immunodeficiency virus-2 (HIV-2) infections among homosexual men from Bombay is discussed. GOAL OF THE STUDY: To determine the extent of presence of anti-HIV-1, anti-HIV-2 antibodies, or both anti-HIV-1 and anti-HIV-2 antibodies among homosexual men in India. STUDY DESIGN: Sixty-three blood samples were collected from two STD clinics of Bombay over a 6-month period from men with a history of homosexual behavior who were asymptomatic for HIV-infection. The mean age of the subjects was 31.6 years. For serological detection anti-HIV-1 antibody ELISA was used as the primary screening test followed by Western blot to confirm the results. For distinction between anti-HIV-1 and anti-HIV-2 antibody, line immunoassay was used. The sexually transmitted diseases (STDs) were diagnosed clinically, although Venereal Disease Research Laboratory (VDRL) tests were carried out as a routine test for screening STDs. For detection of gonorrhea, Gram stains of urethral smear were done routinely. RESULTS: From the 63 blood samples tested, 10 samples were reactive by ELISA for HIV-1 infection, and three samples were borderline reactive. These three samples were found to be reactive for anti-HIV-2 by the line immunoassay. The above 10 samples were also positive by Western blot for anti-HIV-1 antibody. Two blood samples were positive for both anti-HIV-1 and anti-HIV-2 antibodies. Using clinical diagnosis as the criteria, the different types of STD among the 63 subjects were as follows: condylomata (22), herpes (20), gonorrhea (15), candidiasis (3), and syphilis (3). However with VDRL, seven subjects were found to be reactive. Gram stains indicated gonorrhea in all the 15 subjects. CONCLUSIONS: This study reports for the first time the homosexual transmission of both HIV-1 and HIV-2 infections in India, although heterosexual transmission still is the major mode of transmission of the infection. The associated incidence of STDs among these men and that a few of these subjects were bisexual make them at high risk for transmission of HIV infection.

Adult↗

PubMedDate not supplied

Comparative efficacy of three measles vaccines in Indian children.

A Comparative study of three types of measles vaccines was undertaken among 1005 children. Of these 527 were vaccinated with the Serum Institute of India (SII) vaccine, 230 with Schwarz (SC) and 248 were vaccinated with Edmonston-Zegreb (EZ) vaccine (imported from Zegreb). Though the majority of children reacted favourably with all the three vaccines (SII: 98.43%; SC: 93.40%; EZ: 93.0%) with a rise in titre, but the percentage of seroconversion was significantly higher with the SII vaccine (p < 0.01). The Schwarz and Edmonston Zagreb vaccines showed significantly less GM titre as compared with the other age group i.e. 9-12 months (p < 0.05). With Serum Institute of India (SII) vaccine the GM titres were almost similar in the different age groups. The overall GM titre obtained with the SII vaccine was significantly higher than the SC vaccine (p > 0.001) as well as the EZ vaccine (p > 0.001). It is of interest to note that among the infants, 22.5% children had measles antibody in them before vaccination.

Antibodies, Viral↗

PubMedDate not supplied

Epstein-Barr virus in nasopharyngeal carcinoma in Indian patients.

Formalin fixed paraffin embedded tissue blocks from 40 cases of nasopharyngeal carcinoma were investigated for the presence of Epstein-Barr virus (EBV). Heminested polymerase chain reaction was employed to amplify U 2 region of EBV DNA coding for EBNA 2 gene. This is the first study of its kind carried out in India. EBV was detected in 28 out of 40 (70%) nasopharyngeal carcinomas. Type A EBV was identified in 20 cases (71.4%), type B in 7 cases (25%) and coinfection in one case (3.5%). Either type A, or type B EBV, was identified in 22 out of 23 cases (95.7%) of undifferentiated nasopharyngeal carcinoma and 6 out of 15 cases (40%) of non keratinized squamous carcinoma. The higher incidence of EBV in non keratinized squamous carcinoma of nasopharynx assumes importance in view of the contrary reports in other studies. 26 cases were from Western India, of which 15 (57.6%) showed presence of type A EBV and 2 (7.6%) type B EBV. From Eastern Indian particularly Assam, 4 our of 5 cases showed positivity for type B EBV and 1 a coinfection. Whereas, from Bihar 3 out of 4 cases showed presence of type A EBV. From Middle East (Arabs) type A EBV was detected in 3 out of 5 cases of nasopharyngeal carcinomas. Geographically, type A EBV was far more prevalent in Western India, while in Eastern India particularly Assam, all five vases were positive for type B EBV. Thus, a significant variation in the type of EBV infection was observed in nasopharyngeal carcinoma in different ethnic populations in India.

Adult↗

PubMedDate not supplied

Singular anti-RNA virus-directed proteins.

AIMS: To additionally purify and characterise the anti-RNA virus-directed protein termed p14. MATERIALS AND METHODS: Antiviral assays of p14 against RNA and DNA viruses were carried out and its antigenic similarities with chicken interferon (CIFN) were studied. HPLC-Reverse Phase of p14 was performed to further purify p14. RESULTS: p14 showed antiviral activity against RNA viruses only and not against DNA viruses. It was antigenically distinct from CIFN. Purification of p14 yielded three proteins with antiviral activity, which had different physico-chemical properties than those described for interferons. CONCLUSIONS: The data presented on the antiviral, immunological and physico-chemical properties, establish the unique nature of p14 vis-á-vis those of interferons.

Animals↗

PubMedDate not supplied

Strategies for eradication of poliomyelitis--the Indian experience.

Substantial progress has been made towards achieving global eradication of poliomyelitis by the end of the year 2000; the goal set by the World Health Assembly in May 1988. The basic strategies to eradicate polio are: attaining high routine coverage with at least three doses of OPV; conducting national immunization days (NIDs) in polio endemic countries; establishing a sensitive system of acute flaccid paralysis (AFP) surveillance to track wild poliovirus circulation; and conducting "mopping-up" immunization when polio is reduced to focal transmission. By the end of 2000. India was in the midst of the sixth National Immunization Days (NIDs). Surveillance system for Acute Flaccid Paralysis (AFP) continued to achieve the recommended non-polio AFP rate of at least 1 per 100,000 population < 15 years per year (1.88 for week 51 ending 23rd December 2000), the adequate stool specimen collection rate was 83% that met the target of > 80%. Some States in the south and west have started to implement mopping-up immunization campaigns as the end-stage strategy to eliminate the last remaining foci of transmission. While most of India appears to be well placed to eradicate polio by the end of 2000 or shortly thereafter, concerns remain about low coverage in parts of the densely populated northern States of Uttar Pradesh and Bihar where high intensity transmission persists. The Government of India has embarked upon an intensified strategy that relies on extra rounds of NIDs; house-to-house immunization to reach previously missed children; and aggressive mopping-up campaigns including pre-emptive mopping-up in the known reservoirs in Uttar Pradesh and Bihar. Extensive microplanning and supervision of the supplementary immunization activities is critical to achieve the target of polio eradication.

Communicable Disease Control↗

PubMedDate not supplied

Detection of hepatitis B virus DNA in donor blood by the polymerase chain reaction.

BACKGROUND: Blood collected from voluntary donors at local blood banks and blood donation camps was screened for the hepatitis B virus genome using the polymerase chain reaction and for viral markers by standard serological techniques. The sensitivities of the two screening strategies were compared. METHODS: One hundred and twenty-six blood samples were tested for HBV serological markers--HBsAg, anti-Hbs and anti-HBc--by ELISA: The same samples were also subjected to the polymerase chain reaction using primers made by us. RESULTS: Analysis of the polymerase chain reaction amplified products revealed that 24% of the blood samples which tested negative for HBsAg using the ELISA technique were positive for HBV DNA by the polymerase chain reaction. All the HBsAg positive samples (by ELISA) were also positive by the polymerase chain reaction (which detected additional samples as well). Anti-HBc antibodies showed a much greater concordance with the polymerase chain reaction. CONCLUSIONS: The results emphasize that the screening strategies for donor blood need to be re-evaluated in order to check inadvertent transmission of hepatitis B virus during blood transfusion. The ELISA technique to detect HBsAg as the sole serological marker is inadequate to indicate the actual prevalence of hepatitis B virus in the donor blood. The polymerase chain reaction may be a better screening test. If this is not available, the detection of anti-HBc antibodies appear to be a better means of screening blood than HBsAg.

Base Sequence↗

PubMedDate not supplied

Human immunodeficiency virus-1 infection in spouses of seropositive individuals.

BACKGROUND: Unprotected sex can lead to transmission of the human immunodeficiency virus-1 (HIV-1) to the spouse of an infected individual. We studied the incidence of HIV-1 infection in the spouses of cases diagnosed to have HIV-1 infection by serology and the polymerase chain reaction (PCR). METHODS: Blood samples collected from 9 index cases and their respective spouses were tested for HIV-1 infection by ELISA, Western blot (WB) and PCR as well as from 10 healthy individuals with no high-risk behaviour. DNA extracted from both plasma and peripheral blood mononuclear cells was amplified by PCR, using multiple primer pairs for distinct regions of the HIV-1 genome. Specificity of the PCR product was demonstrated by hybridization to an oligonucleotide probe. RESULTS: All the index cases which were seropositive by ELISA and WB were also positive by PCR of plasma extracted DNA. Eight of the spouses were seronegative. Of these seven were positive by PCR--one spouse was negative by ELISA but showed a p55 band on WB and was positive by PCR. One spouse was negative by serology and PCR. The spouse belonging to the lone concordant couple was positive by serology and PCR. Except for one index case, PCR signals were obtainable only from DNA extracted from plasma but not from the DNA extracted from peripheral blood mononuclear cells. The control samples were negative by serology and PCR. CONCLUSION: It is possible to detect HIV-1 infection by PCR using DNA extracted from plasma even when the individuals are negative by ELISA and WB. It can help in the early counselling of HIV infected persons and their spouses.

AIDS Serodiagnosis↗

PubMedDate not supplied

Counselling in HIV/AIDS--an Indian perspective.

AN overview of the general principles of counselling for HIV/AIDS are overviewed. Relevance of 'shared confidentiality' in Indian context is recommended.

Acquired Immunodeficiency Syndrome↗

PubMedDate not supplied

Immunogenicity of immunostimulating complexes of Japanese encephalitis virus in experimental animals.

Immunogenicity of immunostimulating complexes (ISCOMs) of Japanese encephalitis virus (JEV) were studied in mice, rabbits and monkeys. Two doses of JE ISCOMs elicited a strong immune response in mice with an uniform distribution in IgG subclasses. Different time intervals between the two doses of ISCOMs led to similar titers of antibodies. Rabbits and monkeys immunized with ISCOMs developed strong neutralizing immune, response. Mice immunized with ISCOMs demonstrated cell-mediated immunity (CMI) as evidenced by T cell proliferation and macrophage migration inhibition (MMI) assays.

Animals↗