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Biomedical subjects

N Chatterjee

Publications and source records attributed to N Chatterjee.

At least 37 records · Page 2Linked to original sources
PubMed1999

Preventing syphilis: lessons from a survey of two inner-city communities in Houston, Texas.

To develop a relevant, community-based prevention campaign, the authors examined, using street-intercept interviews, syphilis-related knowledge, circulation of information, and screening and treatment practices among four hundred residents of two inner-city communities in Houston, Texas, where syphilis case rates exceed city, county, and national averages. Although awareness of syphilis was near universal, one-fourth of the respondents thought syphilis was incurable, and a large proportion confused syphilis with other sexually transmitted diseases (STDs), mentioning discharge and burning or itching in the genital area as symptoms. Almost four out of five respondents were aware of free treatment and screening facilities in the local area, yet, less than two of five expressed the intention to get tested within the next month. Only 22 percent had seen or heard anything about syphilis in the past twelve months. The resultant prevention campaign is discussed along with implications for the development of comprehensive STD prevention and control campaigns in similar poor and underserved communities.

Adolescent↗
PubMed1998

Expression and activity of p67 are induced during heat shock.

p67, a cellular glycoprotein, protects eIF2 alpha from phosphorylation by inhibitory kinases such as PKR and HCR. p67 promoter contains heat shock element (HSE). To investigate whether this HSE of p67 has any role during heat-shock, rat tumor hepatoma cells were transiently transfected with CAT reporters linked to p67 promoter with HSE and without HSE. Heat shock induced CAT activity when p67 promoter contained HSE and this induction was not observed when HSE was deleted from the p67 promoter. In response to heat-shock, the endogenous p67 mRNA was also induced to more than 36-fold, and much of it translated into protein which was modified by GlcNAc moieties. The time of induced glycosyl modification at the later stages of the heat-shock correlates with the reduced level of eIF2 alpha phosphorylation. During later stages of the heat shock of animal cells, there is a preferential translation of a small class of messages encoding heat shock proteins. Our results suggest that the expression and activity of p67 are induced at the later stages of the heat-shock, and may be involved in the preferential translation of the heat-shock messages.

Aminopeptidases↗
PubMed1998

Health-care utilization by disabled persons: a survey in rural Bangladesh.

The purpose of the present study was to examine the utilization of health services by disabled persons in rural Bangladesh and to identify associated factors to inform the development of appropriate health services. Household surveys were conducted in two villages of Bangladesh by a trained primary-care specialist who lived in the study area for 4 months. About 81% of the sample had utilized some form of health care with more than half consulting unqualified practitioners of modern medicine. Disabled persons whose families perceived they were disabled were 14 times more likely than others to seek treatment. Being male and in the economically productive age group, having an acquired disability and having some form of belief about disability causation were associated with utilization. The conclusions of the study are that social and cultural barriers prevent certain groups, notably women and demographically dependent age groups, from accessing health care. Those who are economically beneficial to the family usually utilize health services. A combination of educational and economic initiatives such as a disability benefits allowance would strongly promote the health of disabled persons and create a general awareness of disability in Bangladesh. A long-term programme which includes disability training for health-care workers and use of financial institutions and existing local government infrastructure for intensive rehabilitation will improve quality of life for disabled persons and is proposed for urgent implementation.

Adolescent↗
PubMed1998

A clinical study to assess chlorpromazine as hypoxic cell sensitizer in head & neck cancer treated with conventional radiation.

A randomized prospective study was conducted to evaluate the effectiveness of chlorpromazine as a sensitizer of radiation in advanced head and neck cancers. Patients with unresectable laryngopharyngeal cancers except glottic cancers, with histologically proven squamous cell carcinoma staged III and IV were accrued for the study. Patients received radiation to a total dose of 6000 cGy in six weeks in both the groups except that patients in the study group received 50 mgs Chlorpromazine (CPZ) in divided doses. Fourteen of 20 patients showed complete response in the control group whereas 34 of 38 patients in chlorpromazine treated group had complete regression of the tumour (p = 0.016). The survival was (p = 0.08) better in patients receiving CPZ. This preliminary study shows beneficial effects of chlorpromazine. No adverse effects due to chlorpromazine in conjunction with radiation were documented.

Carcinoma, Squamous Cell↗
PubMed1997

Viral infection. II. Hemin induces overexpression of p67 as it partially prevents appearance of an active p67-deglycosylase in baculovirus-infected insect cells.

The roles of p67-deglycosylase (p67-DG) in the regulation of protein synthesis in baculovirus-infected insect cells were studied. Like vaccinia viral infection, baculovirus infection of insect cells also induced the appearance of a p67-DG. However, p67-DG activity could not be detected because these cells do not contain a detectable level of p67. The baculovirus expression vector system (BEVS), however, promotes significant expression of cloned p67-cDNA. The expression of p67 was significantly enhanced by the addition of hemin to the growth medium. Maximum enhancement was observed at 5 microM hemin. Data suggest that hemin prevents the activation of latent p67-DG inside the cell and does not have any effect on p67 gene transcription. To gain a better understanding of the mechanism of p67-DG activation and hemin stimulation of p67 synthesis, we have now purified p67-DG from baculovirus-infected insect cells. We prepared antibodies against this protein. These antibodies reacted with a 105-kDa protein in cell extracts from the uninfected insect cells (Sf9), KRC-7, and L929 (animal cells). In addition, these antibodies reacted with an additional 60-kDa protein in the cell extracts of baculovirus-infected Sf9 cells and vaccinia virus-infected KRC-7 and L929 cells. Data are also presented to show that the antibodies against p67-DG reacted more efficiently (40%) with the 60-kDa protein in both hemin-deficient reticulocyte lysate and hemin-deficient baculovirus-infected cells. We suggest that hemin prevents the conversion of an inactive p67-DG into an active form possibly by covalent modification such as protein phosphorylation or protein glycosylation. The active form is more efficiently recognized by the p67-DG antibodies since these antibodies were prepared against the active form of p67-DG.

Acetylglucosaminidase↗
PubMed1997

Cloning and characterization of the promoter region of a gene encoding a 67-kDa glycoprotein.

A rat genomic library constructed in lambda-EMBL3 (SP6/T7) vector () was screened using 32P-labeled rat p67 cDNA. A clone containing a segment of 5'-upstream region of p67 genomic DNA was obtained. The DNA (about 1.7 kilobase pairs) was isolated and characterized. Sequence analysis of this DNA fragment showed that the 898 base pairs at the 5'-end of the upstream region was identical to several long interspersed nucleotide sequences. One hundred forty-eight base pairs at the 3'-end contained the beginning of the first exon including the ATG initiator codon. The remaining 652 base pairs in between contained two AT-rich regions and several regulatory sequences. The mRNA initiation site was identified at 89 base pairs upstream from the translation start codon. The DNA fragment was also analyzed by transient transfection. When linked to a firefly luciferase reporter gene, this fragment enhanced transcription in a rat hepatoma cell line (KRC-7). Using a series of deletions in the DNA, the minimum essential promoter region (from -177 to -60) was identified. The promoter activity was also enhanced by treatment with phorbol 13-myristate 12-acetate (PMA). This enhancement required an AP-1 sequence (-298 to -292; 5'-TGACTCA-3') and a similar sequence (-97 to -88; 5'-ATGACATCAT-3'). Deletion of either of these sequences significantly reduced PMA enhancement. Deletion of both of these sequences almost completely eliminated PMA enhancement.

Aminopeptidases↗
PubMed1997

p67 transcription regulates translation in serum-starved and mitogen-activated KRC-7 cells.

The regulation of protein synthesis was studied in KRC-7 cells (rat hepatoma) grown in complete medium, during serum starvation, and mitogen activation. Upon serum starvation, the cells lost almost completely p67 mRNA, p67 protein, and protein synthesis activity. After phorbol 12-myristate 13-acetate addition, the same serum-starved cells regained p67 mRNA, p67 protein, and protein synthesis activity. Also, the extracts from the serum-starved cells phosphorylated the eukaryotic initiation factor-2 (eIF-2) alpha-subunit. This eIF-2 alpha-subunit phosphorylation was not observed when the extracts from either the cells grown in complete medium or mitogen-activated cells were used (Gupta, S., Wu, S., Chatterjee, N., Ilan, J., Ilan, J., Osterman, J. C., and Gupta, N. K. (1995) Gene Expr. 5, 113-122). We now report the following. 1) The eIF-2 kinase activity was the same in the cells grown in complete medium, after serum starvation, and subsequent mitogen stimulation. However, the eIF-2 kinase in the cells grown in complete medium and also after mitogen activation of the serum-starved cells cannot phosphorylate eIF-2 alpha-subunit as these cells contain p67. After removal of endogenous p67 by p67 antibodies, the extracts from all these cells similarly phosphorylated exogenously added eIF-2. 2) None of the cell extracts showed p67 deglycosylase activity. 3) The p67 mRNA was synthesized in serum-starved cells by expression of a p67 cDNA. The appearance of p67 mRNA in the serum-starved cells was accompanied by the appearance of p67 protein. Also, the rates of protein synthesis in the serum-starved cells were restored nearly to the level observed in the confluent cells. The expression of p67 cDNA also significantly increased protein synthesis rates in the cells grown in complete medium and in mitogen-activated cells. These results show that the loss of protein synthesis activity in serum-starved cells was due to loss of p67 mRNA. The expressed p67 mRNA was stable in serum-starved cells. These results, therefore, suggest that the loss of p67 mRNA in serum-starved cells is due to loss of p67 transcription. The p67 transcription regulates translation.

Aminopeptidases↗
PubMed1996

Human and rodent hantavirus infection in New York State: public health significance of an emerging infectious disease.

BACKGROUND: A case of hantavirus pulmonary syndrome with possible exposure in New York and/or Rhode Island was confirmed in February 1994. OBJECTIVE: To conduct four studies to determine the historical and geographic distribution of human and small-mammal infection with hantaviruses in New York State. METHODS: Enzyme-linked immunosorbent assays were performed on serum samples obtained from 130 humans during a 1978 babesiosis survey, 907 small mammals collected in New York State since 1984, 12 rodents collected in 1994 near the residences of the patients with hantavirus pulmonary syndrome, and 76 New York patients with acute respiratory distress syndrome-like illness (as suspected cases of hantavirus pulmonary syndrome). RESULTS: None of the human serum samples from the 1978 serosurvey showed evidence of hantavirus exposure by enzyme-linked immunosorbent assay. Statewide historical serum samples from white-footed mice showed evidence of Sin Nombre virus infection in 12.0% (97/809) and Seoul-like virus infection in 9.6% (78/809). Site-specific seropositivity rates were as high as 48.5% with Sin Nombre virus during 1 year (1984). Two of 12 mice captured near the residences of a human patient were positive for Sin Nombre virus by enzyme-linked immunosorbent assay, yet were negative for viral RNA by polymerase chain reaction. None of the patients with suspected hantavirus pulmonary syndrome was serologically reactive for Sin Nombre virus. CONCLUSIONS: We provide serologic evidence of small-mammal infection with hantaviruses in New York State as long ago as 1984. Human cases of hantavirus pulmonary syndrome are rare in New York, and data indicate that transmission to humans is probably infrequent. A unique set of host, agent, and environmental factors may be necessary to cause hantavirus pulmonary syndrome in humans.

Adolescent↗
PubMed1996

An overview of the initial experience with AK-2123 as a hypoxic cell sensitizer with radiation in the treatment of advanced head and neck cancers.

PURPOSE: AK-2123 (Senazole) is a nitrotriazole with a reported potential for hypoxic cell sensitization. The present study was conducted to evaluate hypoxic cell potentiation in patients with advanced head and neck cancer treated with discontinuous accelerated hyperfractionated radiation. METHODS AND MATERIALS: Histologically proven unresectable oro-pharyngeal cancers Stage T3-4, NO-3 and M0 were randomly allocated to receive discontinuous accelerated hyperfractionated radiation alone or with AK-2123. AK-2123 (880 and 990 mg) was administered as an i.v. infusion between the first and second fraction of radiation for 10 days in two groups of patients. Initial response as a surrogate end point has been analyzed for comparison and documented for follow-up status. RESULTS: A 100% complete response was observed in both the AK-2123-treated groups (880 mg and 990 mg), while a 44.4% complete response was observed in the control group. There were no treatment-related deaths. Neurotoxicity was not reported. CONCLUSION: AK-2123 (Senazole) when administered with discontinuous accelerated hyperfractionated radiation showed a significant potentiation that, therefore, requires further evaluation.

Adult↗
PubMed1996

Assessment of chlorpromazine as radiation sensitizer and protector.

In vitro studies of chlorpromazine (CPZ) a popular anti-psychotic drug has shown radiation sensitizing effects at higher celluar concentration and protective effect at a lower concentration. The present study was designed to evaluate both sensitizing and protective effects in the treatment of advanced cancer of the cervix treated with hypofractionated external radiation and intratumoural injection of chlopromazine. Twenty patients were treated with intratumoural CPZ and radiation, while, 23 patients received radiation alone. A 52.94% complete response was noted in CPZ arm while 39.1% complete response in the control. A trend towards improved response is seen in CPZ group. Similarly patients who received CPZ showed significantly low proctitis rates.

Carcinoma, Squamous Cell↗
PubMed1995

Protective effect of fluoroquinolones on dapsone induced erythrolysis.

Various quinolones have varied effects on the preservative activity of blood cells. Nalidixic acid causes hemolysis in G-6PD deficient patients where as ofloxacin has been found to possess preservative action of WBCs. The present study was undertaken to see the effect of various fluoroquinolones on RBC membrane. The effect of quinolones like ciprofloxacin, ofloxacin and norfloxacin and nalidixic acid in the dose of 5 micrograms/ml was studied on dapsone induced, in vitro hemolysis of rabbit RBC, using the osmotic fragility test. The mean corpusular fragility (MCF) with various agents were as follows: (mean +/- SE) saline; 5.23 +/- 0.21; dapsone, 6.57 +/- 0.23; ofloxacin, 3.81 +/- 0.13; ofloxacin and dapsone, 5.13 +/- 0.11; nalidixic acid, 6.28 +/- 0.16; nalidixic acid and dapsone, 6.65 +/- 0.13; ciprofloxacin, 3.52 +/- 0.22; ciprofloxacin and dapsone, 4.80 +/- 0.2; norfloxacin, 1.97 +/- 0.23; norfloxacin and dapsone, 4.27 +/- 0.20. The MCF data and shift of the osmotic fragility curves (to the left) show that dapsone induced erythrolysis is significantly protected by ciprofloxacin, ofloxacin and norfloxacin but not by nalidixic acid.

Animals↗
PubMed1995

Regulation of an eukaryotic initiation factor-2 (eIF-2) associated 67 kDa glycoprotein (p67) and its requirement in protein synthesis.

The p67 mRNA level and p67 requirement in protein synthesis were studied using an animal cell (KRC-7, rat tumor hepatoma cell) in culture. p67 mRNA was present in confluent cells but disappeared almost completely from serum-starved cells. However, when PMA was added to the serum-starved cells, p67 mRNA appeared in increasing quantities. Several-fold molar excess of p67 mRNA over that present in confluent cells was detected within 2 h of PMA addition and this level remained the same during the 4 h of the experiment. p67 requirement in protein synthesis was studied using a p67 antisense DNA construct under a metallothionein gene promoter. Expression of this antisense DNA in the presence of zinc in PMA-induced serum-starved cells completely inhibited induced appearance of p67 mRNA and subsequent protein synthesis. These results suggest that p67 is regulated at the mRNA level and also that this protein factor is essential for protein synthesis.

Aminopeptidases↗
PubMed1994

A vaccine that prevents pregnancy in women.

We report here results of clinical trials on a birth control vaccine, consisting of a heterospecies dimer of the beta subunit of human chorionic gonadotropin (hCG) associated noncovalently with the alpha subunit of ovine luteinizing hormone and conjugated to tetanus and diphtheria toxoids as carriers, that induces antibodies of high avidity (K(a) approximately 10(10) M-1) against hCG. Fertile women exposed to conception over 1224 cycles recorded only one pregnancy at antibody titers of > 50 ng/ml (hCG bioneutralization capacity). The antibody response declines with time; fertility was regained when titers fell to < 35 ng/ml. This study presents evidence of the feasibility of a vaccine for control of human fertility.

Adult↗
PubMed1993

Cloning and characterization of complementary DNA encoding the eukaryotic initiation factor 2-associated 67-kDa protein (p67).

The eukaryotic initiation factor 2 (eIF-2)-associated 67-kDa glycoprotein (p67) protects eIF-2 alpha-subunit from inhibitory phosphorylation by eIF-2 kinases, such as heme-regulated inhibitor and double-stranded RNA-activated inhibitor. This promotes protein synthesis in the presence of eIF-2 kinases present in animal cells (Ray, M. K., Datta, B., Chakraborty, A., Chattopadhyay, A., Meza-Keuthen, S., and Gupta, N. K. (1992) Proc. Natl. Acad. Sci. U.S.A. 89, 539-543). In this study, the primary structure of rat p67 is determined by cDNA cloning. Based on the partial amino acid sequences of overlapping tryptic and cyanogen bromide cleaved fragments, degenerate oligonucleotides were synthesized and used as primers for the polymerase chain reaction to amplify the corresponding p67 cDNA fragment from rat liver first strand cDNA. The amplified DNA was then used as a probe to screen a rat tumor hepatoma (KRC-7) cDNA library, and a positive clone covering the entire coding region was obtained. From the cDNA sequence, an open reading frame that encodes p67 as a 480-amino acid protein with a molecular mass of 53 kilodaltons was predicted for the unglycosylated protein. The cloned cDNA was further characterized by in vitro transcription-coupled translation in micrococcal nuclease-treated reticulocyte lysate. The translated product migrated similarly to p67 in SDS-polyacrylamide gel electrophoresis and was precipitated with antibodies against p67. Northern blot analysis of rat liver poly(A)+ RNA showed a single size class (approximately 2 kilobases) of mRNA. The deduced amino acid sequence of the protein showed a highly charged N-terminal region composed of two basic polylysine blocks and an acidic aspartic acid block. The protein also exhibits significant sequence identity in the N-terminal region with human eIF-2 beta-subunit.

Amino Acid Sequence↗