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Biomedical subjects

S Banerjee

Publications and source records attributed to S Banerjee.

At least 343 records · Page 19Linked to original sources
PubMed1996

Taxanes from in vitro cultures of the Himalayan yew Taxus wallichiana.

Culture conditions have been standardized for initiation of callus cultures of Himalayan yew (Taxus wallichiana) using young stem and needle explants from mature trees. Cultures were established on a modified Murashige and Skoog's medium supplemented with various levels of auxins (2.4-D, NAA) and cytokinin (kinetin). A medium containing 0.25 mg/l kinetin and 5.0 mg/l 2.4-D was optimal for stem callus growth whereas the presence of 0.25 mg/l kinetin along with 3.0 mg/l NAA in the medium supported optimal needle callus growth. Growth of stem callus was faster than needle callus growth. Supplementation of ascorbic acid (30 mg/l) amongst various anti-phenolic agents tested significantly reduced browning of initiated callus. Two taxanes (2-deacetoxytaxinine 1 and 2'-deacetoxyaustrospicatine) known to occur in stem bark, have also been isolated from undifferentiated tissue of T. wallichiana in equal or higher yields, for the first time.

Antineoplastic Agents, Phytogenic↗
PubMed1996

Modulatory influence of alcoholic extract of Ocimum leaves on carcinogen-metabolizing enzyme activities and reduced glutathione levels in mouse.

The present study reports the modulatory influence of alcoholic extract from the leaves of Ocimum sanctum on the activities of cytochrome p-450, cytochrome b5, and aryl hydrocarbon hydroxylase enzymes in the liver and glutathione-S-transferase and reduced glutathione level in the liver, lung, and stomach of the mouse. Oral treatment with the leaf extract at 400 and 800 mg/kg body wt for 15 days would significantly elevate the activities of cytochrome p-450 (p < 0.05), cytochrome b5 (p < 0.01, p < 0.001), aryl hydrocarbon hydroxylase (p < 0.05), and glutathione S-transferase (p < 0.05, p < 0.01), all of which are important in the detoxification of carcinogens as well as mutagens. Moreover treatment with 400 and 800 mg/kg body wt of Ocimum extract for 15 days also significantly elevated extrahepatic glutathione-S-transferase (p < 0.05, p < 0.01). The reduced glutathione level was also elevated by treatment with the leaf extract in liver, lung, and stomach tissues (p < 0.01, p < 0.001). Mice fed a diet containing 0.75% butylated hydroxyanisole (positive control) revealed no alteration in the basal hepatic cytochrome p-450 and aryl hydrocarbon hydroxylase level, but hepatic cytochrome b5 and glutathione S-transferase activity in hepatic and extrahepatic organs were elevated in a time-responsive manner (p < 0.05, p < 0.001). The observations suggest further exploitation of the Ocimum leaf extract or its active principle(s) for the chemoprevention of chemical carcinogenesis in different animal model systems.

Animals↗
PubMed1996

The Glasgow Dyspepsia Severity Score--a tool for the global measurement of dyspepsia.

OBJECTIVE: There is currently no reliable tool for providing a global measurement of the severity of dyspepsia in patients with a variety of upper gastrointestinal disorders. We have designed a questionnaire which records frequency of symptoms, effect on routine activities, time off work, frequency of medical consultations, clinical investigations and use of over-the-counter and prescribed medications. The objective of the paper was to assess this questionnaire with respect to reproducibility, validity, responsiveness and performance time. METHODS AND RESULTS: For intra-observer variation, one author interviewed 50 subjects (25 males) including 20 healthy volunteers and 30 with a variety of upper gastrointestinal pathologies. The interview was repeated one week later by the same author who was blinded to the dyspepsia score for the first interview. The second author, who was blinded to the diagnoses and subject identity, scored all the questionnaires. The mean dyspepsia score was 6.78 on Day 1 and was similar at 6.80 on Day 2. The coefficient of variation between Days 1 and 2 was 2%. For inter-observer variation, 30 patients with non-ulcer dyspepsia (NUD) were interviewed by one author and the interview was repeated on a separate occasion within 24 h by a second author who was blinded to the score from the first interview. The mean dyspepsia score for the first author was 10.7 and for the second author 10.9 with a coefficient of variation between the two authors of 8%. Validity was assessed by comparing the dyspepsia scores in healthy volunteers and patients with upper gastrointestinal diseases. The mean score in 80 healthy volunteers was 1.16 (range: 0-7) and was significantly higher in 70 duodenal ulcer (DU) patients (mean score 11.1, range: 6-16) and 80 NUD patients (mean score 10.5, range: 6-17) (P < 0.001 for both vs. healthy volunteers). Responsiveness was assessed by comparing dyspepsia scores before and one year after eradication of Helicobacter pylori infection in 42 DU patients. The mean dyspepsia score before eradication was 11.4 (range: 6-16) and fell to 1.33 (range: 0-11) one year after eradication (P < 0.001). The mean time taken to complete 150 questionnaires was 4 min (range: 3-5.5 min). CONCLUSION: This new questionnaire for assessing the severity of dyspepsia is highly reproducible and has high validity and responsiveness. In addition, it is simple and rapid to perform. It provides a valuable tool for assessing the response to treatment in patients with dyspepsia.

Adolescent↗
PubMed1996

Replication of murine coronavirus defective interfering RNA from negative-strand transcripts.

The positive-strand defective interfering (DI) RNA of the murine coronavirus mouse hepatitis virus (MHV), when introduced into MHV-infected cells, results in DI RNA replication and accumulation. We studied whether the introduction of negative-strand transcripts of MHV DI RNA would also result in replication. At a location downstream of the T7 promoter and upstream of the human hepatitis delta virus ribozyme domain, we inserted a complete cDNA clone of MHV DI RNA in reverse orientation; in vitro-synthesized RNA from this plasmid yielded a negative-strand RNA copy of the MHV DI RNA. When the negative-strand transcripts of the DI RNA were expressed in MHV-infected cells by a vaccinia virus T7 expression system, positive-strand DI RNAs accumulated in the plasmid-transfected cells. DI RNA replication depended on the expression of T7 polymerase and on the presence of the T7 promoter. Transfection of in vitro-synthesized negative-strand transcripts into MHV-infected cells and serial passage of virus samples from RNA-transfected cells also resulted in accumulation of the DI RNA. Positive-strand DI RNA transcripts were undetectable in sample preparations of the in vitro-synthesized negative-strand DI RNA transcripts, and DI RNA did not accumulate after cotransfection of a small amount of positive-strand DI RNA and truncated-replication-disabled negative-strand transcripts; clearly, the DI RNA replicated from the transfected negative-strand transcripts and not from minute amounts of positive-strand DI RNAs that might be envisioned as artifacts of T7 transcription. Sequence analysis of positive-strand DI RNAs in the cells transfected with negative-strand transcripts showed that DI RNAs maintained the DI-specific unique sequences introduced within the leader sequence. These data indicated that positive-strand DI RNA synthesis occurred from introduced negative-strand transcripts in the MHV-infected cells; this demonstration, using MHV, of DI RNA replication from transfected negative-strand DI RNA transcripts is the first such demonstration among all positive-stranded RNA viruses.

Animals↗
PubMed1996

Mental disorder in an elderly home care population: associations with health and social service use.

BACKGROUND: Home care services maintain people in their own households by providing practical help such as with housework, shopping and personal care. In this study associations between mental disorder and health and social service use, demographics and activity limitation are investigated. METHOD: A cross-sectional study with random cluster sampling of people over 65 receiving home care in Lewisham. Mental disorder was rated using the GMS/AGECAT system. RESULTS: We interviewed 169/177 eligible individuals, a response rate of 96%. Forty-six percent of this population were rated as cases of mental disorder (15% organic and 26% depressive). Most (84%) of those with depression did not appear to be receiving appropriate treatment. Home care provision to those with depression (unlike dementia) was only partially explicable in terms of activity limitation. CONCLUSIONS: There is a high level of depressive disorder in this population with little in the way of appropriate primary or secondary care management. Those in sheltered housing seem particularly at risk; depression may lead to increased service use independent of disability.

Activities of Daily Living↗
PubMed1996

Marked rebound acid hypersecretion after treatment with ranitidine.

OBJECTIVES: Dyspeptic symptoms frequently recur rapidly after withdrawal of H2 antagonists, and this might be related to rebound acid hypersecretion. We have studied this phenomenon in healthy volunteers with and without Helicobacter pylori infection. METHODS: Basal and gastrin-releasing peptide (GRP) (40 pmol/kg/h) stimulated acid output, and gastrin concentration were measured in 18 healthy volunteers (nine were H. pylori positive). Studies were performed before and at 60 h and 10 days after completion of a 60-day course of ranitidine 300 mg nocte. RESULTS: In the H. pylori-negative healthy volunteers, basal acid output increased by a median of 137% 2 days after stopping ranitidine therapy compared with pretreatment values (p = 0.01) and returned to pretreatment values by day 10 posttreatment. Their GRP-stimulated acid output increased by a median of 108% 2 days post ranitidine (p < 0.01) and remained slightly increased at day 10. In H. pylori-positive healthy volunteers, basal acid output increased by a median of 96% 2 days after ranitidine therapy ceased (p < 0.01) and returned to pretreatment values by day 10 posttreatment. Their GRP-stimulated acid output also increased by a median of 56% 2 days posttreatment and returned to pretreatment values by day 10. The increase in acid output both basal and in response to GRP was not accompanied by any rise in gastrin concentration in either the H. pylori-positive or -negative subjects. CONCLUSIONS: Ranitidine therapy is associated with marked rebound hypersecretion of acid, and this may contribute to rapid resurgence of symptoms after therapy has been discontinued.

Anti-Ulcer Agents↗
PubMed1995

Limited heterogeneity in T-cell receptor V beta chain gene expression in arthritic joints of BUB/BnJ (H-2q) mice--a T-cell receptor V beta a strain.

We have earlier shown that T-cells in arthritic joints and LNs of B10.Q mice (H-2q, TCR V beta b) use a restricted number of TCR V beta chain genes (V beta 6, 8, 9). In the present study, we have investigated the TCR V beta chain gene expression in arthritic joints and LN of BUB/BnJ mice (H-2q, TCR V beta a). Mice were immunized with [table: see text] chicken type-II collagen, and arthritic joints and draining LNs were removed at the onset of arthritis and the TCR V beta chain gene expression was studied by PCR. A restricted usage of TCR V beta was observed in both the tissues. A dominant usage of TCR V beta 4, 7, and 15 was found in the LNs while TCR V beta 3 and 10 were predominantly expressed in arthritic joints in the majority of the arthritic mice (5/7). Our results indicate that (a) in H-2q mice with CIA there is a restricted usage of TCR V beta chain genes regardless of the TCR V beta genotype; and (b) in the absence of TCR V beta 8 and 9, TCR V beta 3 and 10 are predominantly used by joint-infiltrating T-cells.

Amino Acid Sequence↗
PubMed1995

Mice deficient in IL-1 beta-converting enzyme are defective in production of mature IL-1 beta and resistant to endotoxic shock.

IL-1 beta-converting enzyme (ICE) cleaves pro-IL-1 beta to generate mature IL-1 beta. ICE is homologous to other proteins that have been implicated in apoptosis, including CED-3 and Nedd-2/lch-1. We generated ICE-deficient mice and observed that they are overtly normal but have a major defect in the production of mature IL-1 beta after stimulation with lipopolysaccharide. IL-1 alpha production is also impaired. ICE-deficient mice are resistant to endotoxic shock. Thymocytes and macrophages from the ICE-deficient animals undergo apoptosis normally. ICE therefore plays a dominant role in the generation of mature IL-1 beta, a previously unsuspected role in production of IL-1 alpha, but has no autonomous function in apoptosis.

Animals↗
PubMed1995

A prospective study of endogenous estrogens and breast cancer in postmenopausal women.

BACKGROUND: Circumstantial evidence links endogenous estrogens to increased risk of breast cancer in women, but direct epidemiologic support is limited. In particular, only a few small prospective studies have addressed this issue. PURPOSE: Our purpose was to assess breast cancer risk in relation to circulating levels of the two major endogenous estrogens, estrone and estradiol, measured before the clinical onset of the disease. METHODS: The association between serum levels of estrogens and the risk of breast cancer was examined in a prospective cohort study of 14,291 New York City women, 35-65 years of age, who received screening for breast cancer at the time of blood sampling and who had not been diagnosed with breast cancer. During the first 5 1/2 years of study, we identified 130 breast cancers among the postmenopausal group (7063 women, 35,509 person-years). The case subjects and twice as many postmenopausal control subjects were included in a case-control study nested within the cohort. Biochemical analyses for percent free estradiol, percent estradiol bound to sex hormone-binding globulin (SHBG), total estradiol, estrone, and follicle-stimulating hormone were performed on sera that had been kept at -80 degrees C since sampling. RESULTS: For increasing quartiles of total estradiol, the odds ratio (ORs) of breast cancer, as adjusted for Quetelet index (weight in kilograms divided by the square of the height in meters), were 1.0, 0.9, 1.8, and 1.8 (P value for trend = .06); the ORs for increasing quartiles of estrone were 1.0, 2.2, 3.7, and 2.5 (P value for trend = .06). For increasing quartiles of free estradiol, defined as the fraction of estradiol that is not bound to proteins, the Quetelet index-adjusted ORs of breast cancer were 1.0, 1.4, 3.0, and 2.9 (P value for trend < .01). When we considered the percent of estradiol bound to SHBG, the Quetelet index-adjusted ORs were 1.0, 0.70, 0.40, and 0.32 (P value for trend < .01), thus suggesting a strong protective effect. These associations persisted or became even stronger when analyses were restricted to women whose samples had been drawn 2 or more years before breast cancer diagnosis. CONCLUSIONS: These data represent the first confirmation in a large prospective epidemiologic study of a link between circulating estrogens and breast cancer risk. Although estrogen levels appeared to fall within the conventional limits of normality in all women under study, those who subsequently developed breast cancer tended to show higher levels of estrone, total estradiol, and free estradiol, and a lower percent of estradiol bound to SHBG than women who remained free of cancer. IMPLICATIONS: Factors that increase endogenous estrogen production or reduce the binding of estradiol to SHBG may increase a woman's risk of developing breast cancer later in life.

Breast Neoplasms↗
PubMed1995

Modulatory influence of camphor on the activities of hepatic carcinogen metabolizing enzymes and the levels of hepatic and extrahepatic reduced glutathione in mice.

The present paper deals with the modulatory influence of camphor on the activities of hepatic phase I and phase II drug metabolising enzymes and the levels of hepatic and extrahepatic reduced glutathione contents in the mouse. Female Swiss albino mice (8-9 weeks old) were treated daily by oral route for 20 days with 50, 150 or 300 mg/kg body weight of camphor dissolved in 0.1 ml of olive oil. Camphor only at the 300 mg/kg body weight dose level caused a significant increase in the activities of cytochrome P450 (P < 0.05), cytochrome b5 (P < 0.05), aryl hydrocarbon hydroxylase (P < 0.05) and glutathione S-transferase (P < 0.05). These modulatory effects were comparable with those induced by 0.75% BHA diet given for 20 days (positive control group). The reduced glutathione level was elevated significantly in liver (P < 0.05) by camphor only at the 300 mg/kg body weight dose level and in liver, lung and stomach (P < 0.05) by BHA.

Animals↗
PubMed1995

Histopathological changes induced by chronic nonlethal levels of elsan, mercury, and ammonia in the small intestine of Channa punctatus (Bloch).

Histopathological changes in the intestine of Channa punctatus induced by chronic nonlethal levels of Elsan (211 ppb), mercury (16.7 ppb), and ammonia (15.64 ppm) were studied at 7-day intervals for 90 days and the data were presented only for days (7, 28, 63, and 90) when the most conspicuous changes were noted after treatment. In the earlier phases of Elsan treatment (7 and 28 days) overall destruction of the structure of villus and other layers was prominent. Histopathology of the intestine of C. punctatus, after 63-day Elsan exposure, could be described as collapsed villi with the tips merged with each other to give a flattened appearance. Ninety-day Elsan exposure demonstrated severe damage in the longitudinal muscle layer. After 7-day mercury treatment a high degree of necrosis was indicated by submucosal area, whereas 28-day mercury treatment revealed collapsed villi due to necrotic mucosal cells and goblet cells. Mercury treatment for 63 days caused disarray of all the layers, but some improvement of villus organization was noted in fish treated with mercury for 90 days. Seven-day exposure to ammonia deteriorated the normal structure of the villus, whereas in 28-day ammonia exposure, lesions were predominant in the submucosal layers. Sixty-three-day ammonia treatment demonstrated an effect similar to that produced by Elsan, associated with a more complete destruction of all the layers. Fishes under ammonia treatment for 90 days demonstrated extensive damage to the mucosal folds. The major changes in thickness of different layers of the intestine were also evaluated.(ABSTRACT TRUNCATED AT 250 WORDS)

Ammonia↗