Biomedical subjects

C Ghosh

Publications and source records attributed to C Ghosh.

At least 37 records · Page 2Linked to original sources

PubMed1997

A search for cholera toxin (CT), toxin coregulated pilus (TCP), the regulatory element ToxR and other virulence factors in non-01/non-0139 Vibrio cholerae.

Twenty-four selected non-O1/non-O139 Vibrio cholerae strains were examined for the presence of virulence associated genes like ctxA, tcpA, toxR and the repetitive sequence (RS element). Seventeen of these were isolated from diarrhoeal stool samples while the remaining seven were of local environmental origin. Nine and four respectively of these strains were positive for ctxA and tcpA by Multiplex PCR analysis. The majority (16 out of 18 tested) of the strains (including the four tcpA + strains) contained toxR sequences as determined by another PCR assay. The presence of RS element was demonstrable in ctxA+ strains only. Interestingly, three of these non-O1/non-O139 strains were shown to contain all the three virulence associated genes (ctxA, tcpA and toxR) as well as the RS element. Two of these belonged to serogroups 037 (V2) and 064 (CG15) while the third one (V315-1) was untypable. These three strains also produced cholera toxin, expressed toxin coregulated pilus (TCP) and/or TcpA related antigens when grown under appropriate culture conditions. Southern hybridization analysis of their chromosomal DNA fragments using DNA probes representing ctxA, zot, ace and RS element revealed that the strains V2 and CG15 contained, at least, two complete copies of the CTX genetic element, while the strain V315-1 had three or more copies of the same. Presence of the RS element in these strains led to tandem duplication of the CTX genetic element in the chromosome of V2 and V315-1, but not in CG15 where the copies were likely to be present at different loci. These results also indicate the presence of additional copies of incomplete "core region' with zot and ace genes, but not ctxA, in strains V2 and CG15. The significance of these results in terms of the pathogenic and epidemic potential of V. cholerae strains is discussed.

Animals↗

PubMed1997

Phase III controlled evaluation of sucralfate to alleviate stomatitis in patients receiving fluorouracil-based chemotherapy.

PURPOSE: Stomatitis is a major dose-limiting toxicity of bolus fluorouracil (5FU)-based chemotherapy regimens, despite the use of oral cryotherapy. Pursuant to preliminary data that suggested a sucralfate oral solution could alleviate chemotherapy-induced oral mucositis, we developed a prospective trial to test this contention. PATIENTS AND METHODS: A phase III, double-blind, placebo-controlled clinical trial was designed. Patients were entered onto the study at the time of the first cycle of 5FU-based chemotherapy. All patients received oral cryotherapy for 30 minutes with each dose of 5FU. In addition, each patient was randomized to receive either a sucralfate solution or a placebo solution to be used if they developed mouth tenderness or mouth sores. The study solution was to be used four times daily for 7 days starting on the first day of mouth tenderness or mouth sores. Stomatitis scores were determined by health care providers and by patients themselves. RESULTS: There was a total of 131 assessable patients entered onto this trial, 50 of whom developed mucositis and used the study medication (27 sucralfate and 23 placebo). There was no suggestion of any difference in stomatitis severity or duration on either protocol arm. CONCLUSION: The resultant data from this clinical trial did not support the prestudy hypothesis that sucralfate would be beneficial for the treatment of 5FU-induced stomatitis.

Anti-Ulcer Agents↗

PubMed1997

Phase II trial of irinotecan in patients with metastatic colorectal carcinoma.

PURPOSE: To evaluate the objective tumor response rate and toxicities of patients with metastatic colorectal carcinoma treated with irinotecan hydrochloride (CPT-11). PATIENTS AND METHODS: A total of 121 patients with advanced colorectal carcinoma--90 with prior fluorouracil (5-FU) exposure and 31 chemotherapeutically naive patients--were enrolled between May 1993 and June 1994. Patients were treated with CPT-11 at 125 mg/m2 intravenously weekly for 4 weeks followed by a 2-week rest. RESULTS: Among 90 patients with prior 5-FU chemotherapy, 12 partial responses were observed (response rate, 13.3%; 95% confidence interval [CI], 7.1% to 22.1%). Among 31 chemotherapy-naive patients, eight had partial responses (response rate, 25.8%; 95% CI, 11.9% to 44.6%). The median response duration as measured from time of initial treatment for the two groups was 7.7 months and 7.6 months, respectively. The major adverse reactions were gastrointestinal and hematologic. The incidence of grade 3 or 4 diarrhea was 36.4%, while the overall incidence of grade 3 or 4 leukopenia was 21.5% of patients. Only four of 121 patients (3.3%) developed neutropenic fever (grade 4 neutropenia with > or = grade 2 fever). The incidence of grade 4 leukopenia was higher in patients with prior pelvic radiotherapy (chi2 test P = .04), while the incidence of grade 3 or 4 diarrhea demonstrated no association with previous pelvic irradiation. CONCLUSION: According to the study design, CPT-11 showed promising activity in chemotherapy-naive patients with advanced colorectal carcinoma and modest activity in patients with prior 5-FU exposure. The toxicity with this schedule appears manageable with appropriate dose modification for individual patient tolerance and an intensive loperamide regimen for the management of diarrhea. Care should be taken when treating patients with prior pelvic radiotherapy because of the increased risk of neutropenia.

Adenocarcinoma↗

PubMed1997

Phase III placebo-controlled trial of capsaicin cream in the management of surgical neuropathic pain in cancer patients.

PURPOSE: A minority of cancer survivors develops long-term postsurgical neuropathic pain. Based on evidence that capsaicin, the pungent ingredient in hot chili peppers, might be useful for treating neuropathic pain, we developed the present clinical trial. PATIENTS AND METHODS: Ninety-nine assessable patients with postsurgical neuropathic pain were entered onto this study. After stratification, patients were to receive 8 weeks of a 0.075% capsaicin cream followed by 8 weeks of an identical-appearing placebo cream, or vice versa. A capsaicin/placebo cream was to be applied to the painful site four times daily. Treatment evaluation was performed by patient-completed weekly questionnaires. RESULTS: During the first 8-week study period, the capsaicin-cream arm was associated with substantially more skin burning, skin redness, and coughing (P < .0001 for each). Nonetheless, treatment was stopped for patient refusal or toxicity just as often while patients were receiving the placebo as compared with the capsaicin. The capsaicin cream arm had substantially more pain relief (P = .01) after the first 8 weeks, with an average pain reduction of 53% versus 17%. On completion of the 16-week study period, patients were asked which treatment period was most beneficial. Of the responding patients, 60% chose the capsaicin arm, 18% chose the placebo arm, and 22% chose neither (P = .001). CONCLUSION: A topical capsaicin cream decreases postsurgical neuropathic pain and, despite some toxicities, is preferred by patients over a placebo by a three-to-one margin among those expressing a preference.

Administration, Topical↗

PubMed1996

Phenotypic expression of a mannose-sensitive hemagglutinin by a Vibrio cholerae O1 E1Tor strain and evaluation of its role in intestinal adherence and colonization.

A Vibrio cholerae O1 strain (1150) of the EIT or biotype and Ogawa serotype with haemagglutination (HA) activity was subjected to TnphoA mutagenesis. Out of several mutants isolated, one HA- and another HA+ mutant were further characterised. The HA- mutant showed about 50% reduction in its intestinal adherence capacity in vitro and about 9-fold decrease of its colonisation ability in vivo, as compared to the wild-type strain. Subsequent studies showed that the HA activity of strain 1150 was mediated by a mannose-sensitive haemagglutinin (MSHA). Thus, the phenotypic expression of MSHA appears to be partly responsible for the intestinal adherence and colonisation properties of strain 1150.

Animals↗

PubMed1996

Randomized double-blind placebo-controlled trial of cisplatin and etoposide plus megestrol acetate/placebo in extensive-stage small-cell lung cancer: a North Central Cancer Treatment Group study.

PURPOSE: Megestrol acetate has been reported to improve appetite and quality of life and to decrease nausea and vomiting in patients with cancer anorexia/cachexia. The present trial was formulated to evaluate the impact of megestrol acetate on quality of life, toxicity, response, and survival in individuals with extensive-stage small-cell lung cancer who received concomitant chemotherapy. PATIENTS AND METHODS: Patients were randomized to receive megestrol acetate 800 mg/d orally or placebo. In addition, all patients were scheduled to receive a maximum of four cycles of cisplatin and etoposide chemotherapy. Quality of life was self-assessed at entry onto study, with every cycle of chemotherapy, and 4 months thereafter with a linear visual analog scale. Toxicity was evaluated by patient questionnaire and investigator reports. RESULTS: A total of 243 eligible patients were randomized. Those who received megestrol acetate had increased nonfluid weight gain (P = .004) and significantly less nausea (P = .0002) and vomiting (P = .02). Significant thromboembolic phenomena occurred more often in patients who received megestrol acetate versus placebo (9% v 2%, P = .01). Patients who received megestrol acetate had more edema (30% v 20%, P = .002), an inferior response rate to chemotherapy (68% v 80%, P = .03), and a trend for inferior survival duration (median, 8.2 v 10.0 months, P = .49). These findings may have been influenced by a poorer quality of life of the megestrol acetate group at study initiation. There were no significant changes in quality of life scores over time between either of the study arms. CONCLUSION: Megestrol acetate cannot be routinely recommended for all patients with small-cell lung cancer at the time of chemotherapy initiation. Rather, its therapeutic ratio may be more favorable for patients with problematic cancer anorexia/cachexia.

Anorexia↗

PubMed1995

Leiomyosarcoma of the superior vena cava and azygos vein.

A 40-year-old woman presented with facial swelling and pressure sensation of the ears and sinuses. Chest roentgenography revealed a right paratracheal mass, which was confirmed by a venogram, and transjugular biopsy showed low-grade leiomyosarcoma. The superior vena cava was resected and reconstructed using a spiral vein graft. Pathologic evaluation revealed a low-grade leiomyosarcoma arising from both the superior vena cava and the azygos vein with clear margins.

Adult↗

PubMed1995

Pentoxifylline for treatment of cancer anorexia and cachexia? A randomized, double-blind, placebo-controlled trial.

PURPOSE: Based on evidence that suggests pentoxifylline can inhibit tumor necrosis factor, we set out to evaluate the activity and toxicity of this drug in patients with cancer-associated anorexia and/or cachexia. PATIENTS AND METHODS: Seventy patients with an Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 2 with cancer anorexia and/or cachexia (defined by a weight loss of > or = 5 lb in the preceding 2 months or a caloric intake < 20 kcal/kg/d) were stratified and then randomly assigned to receive pentoxifylline or identical-appearing placebo tablets in a double-blind fashion. Patients' weights were monitored and patient questionnaires were used to assess appetite, toxicity, and perception of benefit. RESULTS: Pentoxifylline failed to improve the appetites of study patients. Pentoxifylline did not appear to cause any toxicity. CONCLUSION: This study failed to demonstrate any benefit of pentoxifylline at this dose and schedule as therapy for cancer anorexia and/or cachexia.

Aged↗

PubMed1995

ES-like cell cultures derived from early zebrafish embryos.

Pluripotent embryonic stem (ES) cell cultures provide an efficient method for genome manipulation with many applications in marine biotechnology. To develop this technology we have been working to derive fish ES cell lines for in vitro studies of embryo cell growth and differentiation and for the generation of transgenic fish. Zebrafish embryonal cell cultures were derived from blastula-stage embryos in LDF medium supplemented with fetal bovine serum, trout serum, trout embryo extract, selenium, insulin, and leukemia inhibitory factor. Cultures derived under these conditions on feeder layers of zebrafish embryonic fibroblasts possessed a diploid karyotype and exhibited an ES-like morphology with elevated levels of alkaline phosphatase enzyme activity. Injection of primary cell cultures derived from embryos of transgenic fish carrying neo produced chimeric fish detected by polymerase chain reaction analysis. Embryo cells cultured on poly-D-lysine substrate in the presence of retinoic acid or Buffalo rat liver cell-conditioned medium (BRL-CM) and a reduced serum concentration differentiated into neuronal cell types exhibiting elevated levels of acetylcholinesterase enzyme activity and expression of neurofilament and glial fibrillary acidic protein.

Acetylcholinesterase↗

PubMed1995

Transmission of Sarcoptes scabiei from animal to man and its control.

Outbreak of Sarcoptes scabiei in animals spilling over to man in close association was observed in two adjacent villages, Fewgram and Nurpur in the district of Birbhum, West Bengal, from mid-November to mid-December, 1991. Nineteen goats and one calf who did not receive any treatment died of sarcoptic manage. All infected animals got cured with external application of deltamethrin, a synthetic pyrethroid and triazapentadiene. Human cases were treated successfully with benzene hexachloride (2%).

Adult↗

PubMed1994

Inhibition of 5-fluorouracil-induced ocular irritation by ocular ice packs.

BACKGROUND: This clinical trial was developed to determine whether ocular ice pack therapy would decrease 5-fluorouracil (5-FU)-induced ocular toxicity. METHODS: Sixty-two patients who suffered from 5-FU-induced ocular toxicity, and were scheduled to receive another cycle of the chemotherapy that caused the ocular toxicity, were entered in this clinical trial. A randomized, crossover design was used, with patients documenting their ocular toxicity by the use of daily diaries. RESULTS: The results from the first cycle of treatment suggested that ocular ice pack therapy decreased 5-FU-induced ocular toxicity (P = 0.056). The 38 evaluable patients in the crossover analyses demonstrated decreased ocular toxicity with ocular ice pack therapy (p = .001). The ocular ice pack therapy was well tolerated by most of the study participants. CONCLUSION: Ocular ice pack therapy appears to lessen 5-FU-induced ocular toxicity to a clinically moderate degree. Better methods for decreasing 5-FU-induced ocular toxicity are necessary.

Conjunctivitis↗

PubMed1994

Derivation and characterization of a zebrafish liver cell line.

ZF-L cells were derived from normal adult zebrafish liver, and have been growing in culture for more than 100 generations. The cells were derived in basal nutrient medium supplemented with fetal bovine serum (FBS), trout serum, trout embryo extract, bovine insulin and mouse epidermal growth factor. After 50 generations in culture, optimal growth of the cells was achieved in medium supplemented with FBS (5%) and trout serum (0.5%). ZF-L cells were hypodiploid (modal chromosome number = 46) and exhibited an epithelial morphology. ZF-L cell homogenates exhibited alanine and aspartate aminotransferase, glucose-6-phosphatase and alkaline phosphatase enzyme activities. The cells synthesized and released several proteins into the culture medium, including a 70 kDa protein recognized by anti-bovine serum albumin IgG.

Albumins↗

PubMed1994

Culture of cells from zebrafish (Brachydanio rerio) blastula-stage embryos.

The zebrafish has become a popular model for studies of vertebrate development and toxicology. However, in vitro approaches utilizing this organism have not been fully exploited due to the absence of suitable cell culture systems. Previously, we developed methods for the culture of cells derived from zebrafish blastula-stage embryos. One of these cultures, ZEM-2, was derived in a complex medium containing trout embryo extract, trout serum and medium conditioned by buffalo rat liver cells. In this study we describe a zebrafish embryo cell line, ZEM-2A, derived from ZEM-2 following selection for growth in a simplified medium. Optimal growth of ZEM-2A cells is attained in nutrient medium supplemented with 5% fetal bovine serum.

Animals↗

PubMed1994

Placebo-controlled trial of hydrazine sulfate in patients with newly diagnosed non-small-cell lung cancer.

PURPOSE: Hydrazine sulfate, an agent that appears to inhibit gluconeogenesis, has been studied in cancer patients for approximately 20 years. There was a recent resurgence of interest in this drug when subset analysis of a small placebo-controlled, double-blind, clinical trial reported improved survival among non-small-cell lung cancer patients with a good performance status who were randomized to receive this drug along with standard chemotherapy. PATIENTS AND METHODS: Patients on this trial had newly diagnosed, unresectable non-small-cell lung cancer and were treated with cisplatin and etoposide. In addition, they were randomized to receive hydrazine sulfate or placebo in a double-blind manner. RESULTS: A total of 243 patients were randomized. Response rates were similar in the two treatment arms. There were trends for worse time to progression and survival in the hydrazine sulfate arm. No significant differences were noted in the two study arms with regard to toxicity or quality of life (QL). CONCLUSION: This trial failed to demonstrate any benefit for patients who received hydrazine sulfate.

Antineoplastic Agents↗

PubMed1993

Iron/ascorbate-induced lipid peroxidation changes membrane fluidity and muscarinic cholinergic receptor binding in rat frontal cortex.

Lipid peroxidation (LP) is a complex process which involves the formation of lipid free radicals and leads to oxidative damage. LP has also been implicated in several neurodegenerative diseases as well as aging. In the present study, we evaluated the effects of the induction of LP in vitro on muscarinic cholinergic (Mch) receptor binding and membrane fluidity in rat brain. Membranes from the rat frontal cortex were peroxidized by adding ferrous sulphate (84 microM) and ascorbic acid (400 microM). Peroxidation was measured as the amount of thiobarbituric acid reactive products formed (nmol malondialdehyde/mg protein). Mch receptor binding was measured 10, 20 and 30 min after peroxidation. Membrane fluidity was evaluated by fluorescence polarization studies using two probes; 1,6-diphenyl-1,3,5-hexatriene (DPH) and 1-[4(trimethylamino)phenyl]-1,3,5-hexatriene (TMA-DPH). Significant alterations in Mch receptor binding (decreased Bmax and increased Kd) were found after peroxidation. Membrane fluidity was also significantly decreased after peroxidation as observed with both probes. The decrease in membrane fluidity was due to an increased cholesterol to phospholipid molar ratio after peroxidation. These data suggest that lipid peroxidation induces changes in membrane dynamics as detected by the fluorescent probes and such changes in membrane microviscosity may be the cause for alterations in Mch receptor kinetics.

Animals↗

PubMed1993

Sarcoptes scabiei in animals spreading to man.

An outbreak of Sarcoptes scabiei in animals was observed from mid-November 1991 to mid-December 1991 in two adjacent villages, Fewgram and Nurpur, in Birbhum District, West Bengal State, India, starting from goats to cattle, then to sheep and even to dogs. Nineteen goats and one cattle died of manage infection. The infection spread to man in the last week of December 1991, and affected forty-two human beings, tending and rearing animals. The animals treated with deltamenthrin (synthetic pyrethroid) and amitraz (triazapentadiene) were completely cured. In man, the disease seemed to be self-limited in some cases and 2% hexachlorobenzene was successfully used for treatment of the others. The outbreak was effectively controlled in March 1992.

Adult↗

PubMed1992

Fluctuation of serum phenytoin concentrations during autologous bone marrow transplant for primary central nervous system tumors.

We reviewed our experience for adult patients receiving oral anticonvulsant therapy during high-dose chemotherapy and autologous bone marrow re-infusion for primary malignant tumors of the central nervous system. Nineteen patients received either iv carmustine (BCNU) 900-1050 mg/m2 and 6120 cGy cranial irradiation (N = 10), iv carmustine 900-1050 mg/m2 and iv cisplatin 200 mg/m2 (N = 8), or iv carmustine 600 mg/m2, iv cisplatin 200 mg/m2, and iv etoposide 2400 mg/m2 (N = 1). Anticonvulsant therapy consisted of phenytoin alone (N = 8), phenobarbital alone (N = 4), carbamazepine alone (N = 2), phenytoin and carbamazepine (N = 2), carbamazepine and phenobarbital (N = 1), and no anticonvulsant therapy (N = 2). Serum anticonvulsant concentrations were monitored frequently and doses adjusted to keep values in the therapeutic range. While phenobarbital and carbamazepine doses remained relatively stable, all patients required increased doses of phenytoin anticonvulsant therapy after beginning chemotherapy (mean onset 3.7 days after initiation of chemotherapy). The increase in phenytoin dose ranged from 50% to 300% above baseline (mean 134%). By the time of discharge from the hospital (approximately 3-4 weeks after the start of chemotherapy) anticonvulsant dose was decreased to near pre-therapy levels. These swings coincided with the initiation of dexamethasone therapy for antiemetic effect and were more pronounced in patients also receiving cisplatin therapy. Due to close monitoring of serum phenytoin concentrations, no instances of toxicity due to excessive drug concentration, or seizures due to subtherapeutic doses, were noted in patients with primary CNS malignancies. Serum phenytoin concentrations fluctuate markedly during high-dose chemotherapy and must be analyzed frequently during the course of therapy.

Adult↗

PubMed1990

Fluidity-dependent Mg2(+)-ATPase activity in membranes from Leishmania donovani promastigotes.

The state of the lipid phase of the membrane plays a key role in the exposure of various receptors, antigens and enzymes on the membrane surface. The fluidity of membranes of Leishmania donovani promastigotes was monitored by two independent methods, i.e. influx of sterol from liposomes and removal of phospholipids by treatment with phospholipase C. The altered sterol/phospholipid ratio, in both cases, provided evidence that the activity of the functionally important membrane-bound enzyme Mg2(+)-ATPase is modulated by the state of the lipid phase of the membrane.

Animals↗