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Biomedical subjects

R Chatterjee

Publications and source records attributed to R Chatterjee.

At least 91 records · Page 5Linked to original sources
PubMed1992

Relative performance of Organon kit in comparison to Du Pont for confirmatory serological testing of HIV infection by western blot test in sera from blood donors.

A total of 32 specimens with different categories of reactivity by Du Pont Western Blot kit comprising of specimens showing full spectrum of HIV-I antigen specific bands, 19 specimens showing total absence of bands and four specimens showing non-specific bands (without any interpretative importance) were subjected to Western Blot testing by Organon test. Of the nine specimens showing full spectrum of bands by Du Pont the correlation with Organon kit was 100 per cent based on WHO criteria. Four specimens with non-specific indeterminate band pattern by Du Pont failed to show any band in Organon kit, indicating that latter to be more specific.

AIDS Serodiagnosis↗
PubMed1991

Chronic ultraviolet radiation-induced increase in skin iron and the photoprotective effect of topically applied iron chelators.

In the skin of albino hairless mice (Skh:HR-1) there is a basal level of non-heme iron. Chronic exposure of mice to sub-erythemal doses of ultraviolet (UV) B radiation results in an increased skin level of non-heme iron. The iron increase may be the result of a UVB radiation-induced increase in vascular permeability, which we measured in vivo with the dye marker Evans Blue. We also observed greater non-heme iron in sun-exposed vs non-exposed body sites of human skin, suggesting that similar events occur in man. Iron may have a role in skin photodamage by participating in formation of reactive oxygen species. These species have been implicated in skin photodamage. It is known that iron can contribute to oxygen radical production by acting catalytically in the formation of species such as hydroxyl radical. While the basal level of skin iron may be available for catalysis, the elevated iron content of UV-exposed skin increases the potential for iron-catalyzed radical production. Topical application of certain iron chelators to Skh albino hairless mice dramatically delayed the onset of UVB radiation-induced skin photodamage. Non-chelating analogs provided no significant protection.

2,2'-Dipyridyl↗
PubMed1991

Antitumor activity of some organotin complexes of hydroxamic acids derived from dibasic carboxylic acid.

The sensitivities of normal and preneoplastic rat hepatocytes have been tested against four organotin hydroxamates in vitro. These organotin hydroxamates are soluble in lipids but not in aqueous medium. The solubility in lipid had initially been utilized in the pilot experiments with Ehrlich ascites tumor cells containing lipids in the ascites fluid. Cytochemical staining of protein and the growths of drug-treated cells in vivo have been studied for Ehrlich ascites tumor cells. Measurement of DNA synthesis, protein content and the cytochemical staining of protein have been employed for normal and preneoplastic hepatocytes. Ehrlich ascites tumor cells and the preneoplastic hepatocytes are markedly sensitive to organotin hydroxamates whereas the normal hepatocytes are less sensitive to these chemicals. The results of the present work are significant, and it may be worthwhile to study the further drug action in vivo.

Animals↗
PubMed1991

Detection of human papillomavirus in cervical swabs from Indian women by cytological and immunocytochemical technique.

Cervical swabs were collected from 88 women in the age group of 17-55 years in Calcutta, India to study the prevalence of human papillomavirus (HPV) infection. The viral infection was demonstrated on the basis of koilocytotic changes in Papanicolaou staining (PAP test) and the presence of viral capsid antigen as detected by immunocytochemistry (IMC test). The PAP and IMC tests revealed 25% and 28.4% of women, respectively, to be positive for HPV infection. Higher frequency (61.1% to 87.5%) of infection was observed in moderate to severe dysplastic lesions. HPV infection was observed to be more frequent in the younger age group (less than 40 years) with 1-2 parity. Although koilocytes were absent in all (n = 51) of the apparently normal subjects, 4 (7.8%) of them were positive for HPV antigen. Except for these, sensitivity of PAP test and IMC test for the detection of HPV was found to be almost similar.

Adolescent↗
PubMed1991

Antimalarial antibody in relation to seroreactivity for HIV infection in sera from blood donors.

A total of 74 specimens from blood donors showing evidence of HIV infection comprising of 40 positive by both ELISA and Western Blot (true positive), 16 positive by ELISA but negative by Western Blot (false positive) and 18 specimens positive by ELISA but showing indeterminate bands in Western Blot were screened for anti-malarial antibody. The prevalence of antimalarial antibody was noted as 62.5%, 56.3% and 66.6% respectively in these groups. None of these groups had any difference in the prevalence of antimalarial antibody with the group of 60 specimens negative for HIV infection by both ELISA as well as Western Blot (true negative) which had a prevalence of antimalarial antibody as 53.3%. The mean titre of antimalarial antibody in the above categories of specimens positive for HIV infection also did not show any difference with that of true negative group. These findings point out that antimalarial antibody does not influence the serological positivity for HIV infection.

Animals↗
PubMed1990

Chronic ultraviolet B radiation-induced biochemical changes in the skin of hairless mice.

Skh:HR-1 hairless mice were irradiated chronically with sub-erythemal doses of UVB radiation, and a number of biochemical parameters in the skin were determined after 6, 12, 18, and 24 wk of exposure. The parameters measured were water, collagen, elastin, and glycosaminoglycan content; collagenase and elastase levels; and Bz-Tyr-OEt (N-benzoyl-L-tyrosine ethyl ester) and BAPNA (alpha-N-benzoyl-DL-arginine-p-nitroanilide) hydrolyzing activities. Data for UVB radiation-exposed and chronological age-matched control mice were compared with respect to unit area and to unit mass of skin. On a unit area of skin basis, UVB radiation exposure increased the level of most parameters. The particular exceptions were collagen and collagenase which remained constant. On a mass of skin basis, though, there is an apparent decrease in collagen content because of the increase in the other skin components. This suggests that there is insufficient collagen in UVB radiation-exposed skin to support the increasing mass of the tissue.

Animals↗
PubMed1990

Photoprotective effect of topical anti-inflammatory agents against ultraviolet radiation-induced chronic skin damage in the hairless mouse.

Albino hairless mice (Skh:HR-1) exposed chronically to suberythemal doses of ultraviolet (UV) radiation display visible and histological alterations in the skin. One alteration is an increase in dermal cellularity, including inflammatory cells. This suggested a role for inflammation in chronic photodamage. We evaluated the photoprotective effect of topical hydrocortisone, ibuprofen, and naproxen against photodamage. All 3 agents protected against UVB radiation-induced visible wrinkling, tumor formation, and histological alterations. Hydrocortisone and naproxen were also evaluated for protection against UVA radiation-induced visible skin sagging and histological alterations. Both were very effective. These data indicate that chronic topical application of anti-inflammatory agents provides broad solar UV spectrum photoprotection.

Administration, Cutaneous↗
PubMed1990

Photoprotective effect of superoxide-scavenging antioxidants against ultraviolet radiation-induced chronic skin damage in the hairless mouse.

Albino hairless mice (Skh:HR-1) exposed chronically to suberythemal doses of ultraviolet radiation develop visible skin changes, histological alterations, and tumors. Topical treatment of mice with solutions of superoxide-scavenging antioxidants (such as alpha-tocopherol, ascorbic acid, propyl gallate and Trolox) prior to each UVB radiation exposure reduced significantly the severity of these events. Tocopherol esters and ascorbyl palmitate were not as effective as the parent compounds in providing protection. The data suggest a role for superoxide in UVB radiation-induced skin photoaging and the protective potential of superoxide scavengers. In contrast, the severity of UVA radiation-induced mouse skin damage was not reduced by topical application of the antioxidants tested here.

Animals↗
PubMed1989

Prevalence of the plasma bovine leukaemia virus blocking factor in cattle from a commercial dairy herd.

The prevalence of the plasma bovine leukaemia virus blocking factor was examined in a commercial herd. The detection of the blocking factor activity depended on the nature of the infected target cells used in the assay. Using the sensitive bovine leukaemia virus-infected target lymphocytes, the factor was found to be significantly more prevalent in infected cattle than in virus-free cattle. Furthermore, in infected cattle, no correlation was observed between the level of bovine leukaemia virus antibody and the presence of the blocking factor.

Animals↗
PubMed1989

Binding of phytohemagglutinin to bovine B lymphocytes and its role in stimulation of expression of bovine leukemia virus genome.

Phytohemagglutinin (PHA) is known to increase the synthesis of bovine leukemia virus (BLV) particles and viral antigens in short-term culture of BLV-infected neoplastic and non-neoplastic lymphocytes. This stimulation of BLV expression has been shown to be due to enhanced transcription of the viral genome by a PHA-induced protein. We have investigated the binding of 125I-labelled PHA to BLV-infected bovine B lymphocytes and subsequent events that may lead to the stimulation of BLV-p25 synthesis. We found that PHA binding to the infected cells were rapid, but only a small fraction of the bound PHA is translocated to nucleus. However, bound PHA dissociated rapidly from the cell membrane, but not from the nucleus when PHA is removed from the culture medium. Furthermore, continuous presence of PHA was not essential for optimal stimulatory activity, instead a minimum incubation with PHA for 6 hr. followed by culturing the infected cells in its absence, was sufficient to exhibit maximal stimulatory activity. Our results raise the possibility that interaction of PHA with the plasma membrane probably triggers synthesis of a protein which in turn enhances the transcription of BLV genome in vitro.

Animals↗
PubMed1987

Isolation and characterization of adenosine kinase from Leishmania donovani.

Adenosine kinase (ATP:adenosine 5'-phosphotransferase, EC 2.7.1.20) has been purified 3250-fold from Leishmania donovani promastigotes using ion-exchange, gel filtration, and affinity chromatography techniques. Both native and sodium dodecyl sulfate-gel electrophoresis of the enzyme revealed a single polypeptide of around 38,000 molecular weight. Biophysical and biochemical analyses of the enzyme reveal unique characteristics different from those of adenosine kinases from other eukaryotic sources. The isoelectric pH of the enzyme is 8.8. In native acrylamide gels the enzyme moves with an RF of about 0.62. The enzyme displays a maximum activity at pH between 7.5 and 8.5 and is dependent upon an optimum ATP/Mg2+ ratio. ATP at high concentration inhibits the reaction. Adenosine and Mg2+ are not inhibitory. EDTA completely knocks off the activity. Enzyme activity is dependent upon the presence of active thiol group(s) at or near the active center. Under a defined set of conditions the enzyme exhibited an apparent Km for adenosine and ATP of 33 and 50 microM, respectively. Of the nucleoside triphosphates tested ATP and GTP were the most effective phosphate donors. Marginal inhibition of activity was detected with other nucleosides as competitors. However, adenosine analogs, such as 7-deaza-adenosine (tubercidin) and 6-methylmercaptopurine riboside at very low concentrations, were found to be excellent inhibitors and substrates as well. S-Adenosylhomocysteine does not inhibit the reaction even at very high concentration.

Adenosine Kinase↗