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Biomedical subjects

N Ghosh

Publications and source records attributed to N Ghosh.

87 records · Page 5Linked to original sources
PubMed1979

Interferon, double-stranded RNA, and RNA degradation: activation of an endonuclease by (2'-5')An.

Among the mediators of interferon action are one enzyme that is activated by double-stranded RNA to convert ATP to (2'-5')An and a second enzyme, an endonuclease, that is activated by (2'-5')An to cleave single-stranded RNA. The binding of (2'-5')An to the endonuclease (partially purified from mouse Ehrlich ascites tumor cells) is revealed by its retention on nitrocellulose filters. This can serve as the basis for an assay of the enzyme. Activation of the enzyme is reversible and is lost upon removal of (2'-5')An:gel filtration of activated endonuclease on Sephacryl S-200 results in an inactive enzyme. The enzyme can be activated again, however, by addition of (2'-5')An. The elution volume of the nonactivated endonuclease from Sephadex G-200 indicates that its molecular weight is 185,000, unusually large for a nuclease. The elution volume of the maximally activated endonuclease from Sephadex G-200 equilibrated with (2'-5')An is not detectably different from that of enzyme that had not been previously activated that was passed through Sephadex G-200 not equilibrated with (2'-5')An. This indicates that the activation does not result in a large change in the size or conformation of the enzyme.

Animals↗
PubMed1979

A double-blind comparison of flupenthixol decanoate and fluphenazine decanoate in the treatment of chronic schizophrenia.

Sixty-four chronic stabilised schizophrenics were studied for 18 months in order to assess the possible difference in therapeutic effects and side effects between flupenthixol decanoate and fluphenazine decanoate. Although certain differences in the BPRS sub-scores in favour of flupenthixol were present at various stages in the study, there was no significant difference between the two drugs in the overall antipsychotic scores at the end of the assessment period; however, more patients on fluphenating required additional therpay for depression or anxiety during the trial period.

Chronic Disease↗
PubMed1969

Studies on the conversion of 60s yeast ribosomes into a 50S component.

The process of conversion of the larger (60s) subunit of yeast ribosomes into a 50s component was studied. The release of any RNA or protein material during conversion was assayed by using (32)P- or (35)S-labelled ribosomes; ribosomal RNA distributions of the particles were examined and protein/RNA ratios of subunits were determined. The change in sedimentation coefficients was found to be due, not to loss of material, but to a structural change. The change in structure was shown by electron microscopy.

Magnesium↗
PubMedDate not supplied

Serodiagnosis of ascariasis with specific IgG4 antibody and its use in an epidemiological study.

In an earlier study Ascaris-specific IgG4 antibody was found to be elevated in cases of ascariasis. However, the usefulness of the elevated levels of this antibody in Ascaris infection as a diagnostic marker has not been well established. In India, in early 1999, blood samples of 83 cases of Ascaris infection, 35 cases of other nematode infection and 53 control subjects (without any helminth infection) were tested for anti-Ascaris IgG4 by ELISA. Further anti-Ascaris IgG4 levels in the blood of Ascaris-infected patients were determined, after eradication of the worms with drugs, at regular intervals to ascertain the duration of elevation of titre of the serological marker following initial infection. This information would indicate the sensitivity of the test as a diagnostic marker for recent infection. Blood samples of 422 rural people were also tested for anti-Ascaris IgG4 titre to ascertain the prevalence of ascariasis in the community. High levels of anti-Ascaris IgG4 antibody (OD 1.246 +/- 0.212) were found in all the 83 Ascaris-infected subjects compared to controls (OD 0.158 +/- 0.047). Anti-Ascaris IgG4 antibody levels of other nematode-infected subjects were comparable to the controls. Anthelmintic treatment of 8 Ascaris-infected subjects caused sequential fall of IgG4 level in their blood, and its titre reached control level within 6 months of deworming. Of 422 individuals from the rural community 229 (54.3%) had significantly high levels of specific IgG4 antibody against Ascaris excretory-secretory antigen, suggesting that they were infested with Ascaris. Thus, this study demonstrated that anti-Ascaris IgG4 antibody is a very sensitive and specific marker for the diagnosis of Ascaris infection. Utilizing this test, a significant number of a rural population could be diagnosed with Ascaris infection in West Bengal, India.

Adolescent↗
PubMedDate not supplied

Support vector machine for optical diagnosis of cancer.

We report the application of a support vector machine (SVM) for the development of diagnostic algorithms for optical diagnosis of cancer. Both linear and nonlinear SVMs have been investigated for this purpose. We develop a methodology that makes use of SVM for both feature extraction and classification jointly by integrating the newly developed recursive feature elimination (RFE) in the framework of SVM. This leads to significantly improved classification results compared to those obtained when an independent feature extractor such as principal component analysis (PCA) is used. The integrated SVM-RFE approach is also found to outperform the classification results yielded by traditional Fisher's linear discriminant (FLD)-based algorithms. All the algorithms are developed using spectral data acquired in a clinical in vivo laser-induced fluorescence (LIF) spectroscopic study conducted on patients being screened for cancer of the oral cavity and normal volunteers. The best sensitivity and specificity values provided by the nonlinear SVM-RFE algorithm over the data sets investigated are 95 and 96% toward cancer for the training set data based on leave-one-out cross validation and 93 and 97% toward cancer for the independent validation set data. When tested on the spectral data of the uninvolved oral cavity sites from the patients it yielded a specificity of 85%.

Algorithms↗
PubMedDate not supplied

Telomerase activity in breast cancer in Western India (Gujarat).

The purpose of this study was to examine the association of telomerase activity with clinical and histopathological prognostic variables in primary breast cancer (n=64). Telomerase activity in breast cancer was also compared with that in benign (n=10) and non-malignant tissues (n=8; post-lumpectomy tissues histopathologically defined as containing no residual tumor). The parameter was assessed using the Telomerase PCR ELISA kit. Values above OD 0.120 were considered positive. Estrogen and progesterone receptors (ER and PgR) were assayed by the dextran-coated charcoal method and levels >10 fmol/mg cytosol protein were taken as positive. Telomerase activity was detected in 20% and 50% of the patients with benign lesions and primary breast cancer, respectively, and in 50% of post-lumpectomy breast tissues histopathologically defined as containing no residual tumor. Telomerase activity was present in all stages of breast carcinoma and showed a significant inverse correlation with lymph node status (p=0.006), lymphatic invasion (p=0.035) and necrosis (p=0.033). Moreover, when stage II patients were grouped according to nodal involvement, a trend towards significance was observed (p=0.055). No correlation was observed with ER and PgR. The results of our study suggest that telomerase activity might be associated with the presence of cancer cells. Furthermore, telomerase activation may occur early in breast cancer and may be periodically downregulated during subsequent tumor progression.

Adult↗
PubMedDate not supplied

Comparison of prolactin, CA 15-3 and TPA in breast carcinomas.

Circulating prolactin, CA 15-3 and TPA were assayed pre-therapeutically and sequentially thereafter from 68 breast cancer patients attending the Gujarat Cancer and Research Institute, Ahmedabad--a regional cancer institute in Western India. The three marker values were correlated with the stage, histologic grade and disease status. At least one of the markers was elevated in 82% of patients. CA 15-3 and TPA levels were elevated with the advancement of stage. Prolactin levels were high in poorly differentiated tumors of pre-menopausal patients. The disease status was effectively reflected by the levels of prolactin and CA 15-3. TPA showed high false positivity so was of no use as an indicator of disease status. Recurrence could be predicted early, with a lead time of 3-6 months using prolactin and CA 15-3.

Adult↗
PubMedDate not supplied

Enhancement of immune response by phenothiazine administration in vivo.

The natural killer (NK) cell activity and PHA-induced mitogenesis of the peripheral blood mononuclear cells (PBMC) were assessed in a group of schizophrenic patients treated with phenothiazines and haloperidol for different lengths of time. Significantly higher levels of NK cytotoxicity and lymphocyte mitogenesis were observed in the patients as compared to those in age and sex-matched healthy volunteers. Enhancement of NK activity in the patients depended on the duration and continuity of treatment with these calmodulin antagonists. Increased susceptibility to chlorpromazine (CPZ, a phenothiazine derivative)-induced in vitro inhibition of basal and mitogen stimulated tritiated thymidine incorporation was observed in the patients' lymphocytes, though the reversibility of CPZ binding was similar in these cells and in normal PBMC. The data suggested that continuous in vivo exposure to phenothiazines and haloperidol resulted in stimulation of lymphocyte activity. The enhanced lymphocyte activity following treatment with calmodulin antagonists may be associated with the antineoplastic activity of these drugs.

Adjuvants, Immunologic↗