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Biomedical subjects

S Ghosh

Publications and source records attributed to S Ghosh.

At least 1,243 records · Page 69Linked to original sources
PubMedDate not supplied

Rifampicin-induced chromatid exchanges in Sarcoma-180 mouse ascites cells.

Sarcoma-180 ascites tumour-bearing male mice were injected i.p. with single dose of 0.5, 2.5, 5 mg/kg body wt. of rifampicin. Cells were sampled for mitotic chromosome analysis 4, 16 or 24 h after treatment. The maximal yield of chromatid-type aberrations induced was found 24 h after treatment with 5 mg/kg of rifampicin. More than 60% of the cells carried at least one chromatid exchange. The majority of these were exchanges derived from breaks in the centromeric heterochromatin.

Animals↗
PubMedDate not supplied

Epidemiological and clinical profiles of acute invasive diarrhoea with special reference to mucoid episodes: a rural community-based longitudinal study.

A study was carried out in 3 villages near Calcutta, India, having a population of 5464, between August 1992 and December 1994. A cohort of rural children below 4 years of age was prospectively observed to determine the clinico-epidemiological aspects of mucoid diarrhoea and examine propensity to invasiveness. Overall, the incidence of diarrhoea was 1.7 episodes/child/year, and that of mucoid and bloody dysentery was 0.8 and 0.2 episodes/child/year, respectively. Children aged 6-11 months had a higher incidence of mucoid diarrhoea (1.3 episodes/child/year) and the peak season occurred in June and July. Multivariate analysis using logistic regression showed that mucoid diarrhoea and bloody dysentery were closely similar in both clinical and laboratory findings, including raised faecal leucocyte count (> 10/high power microscope field [hpf]). However, abdominal pain occurred more frequently in bloody dysentery than in mucoid diarrhoea. Faecal leucocyte count (> 10/hpf) can therefore be used as an indicator for invasiveness of mucoid diarrhoea at the community level.

Age Factors↗
PubMedDate not supplied

Effect of human chorionic gonadotrophin coadministration on ovarian steroidogenic and folliculogenic activities in cyclophosphamide treated albino rats.

Quantitative evaluation of ovarian Delta5,3beta- hydroxysteroid dehydrogenese (HSD) and 17beta - HSD activities along with radioimmunoassay of plasma levels of gonadotrophins (FSH and LH), and estradiol (E2), and quantification of different types of developing follicles and regressive follicles were noted in mature rats of the Wistar strain following treatment with cyclophosphamide at a dose of 5 mg/kg body weight/day for 28 days. A significant reduction in plasma levels of LH and E2 along with significant diminution in the activities of ovarian Delta5,3beta -HSD and 17beta- HSD were observed following cyclophosphamide treatment for 28 days without any change in the plasma level of FSH. This treatment also produced a marked degree of degeneration in different types of follicles. Coadministration of hCG at 5 IU/kg body weight/day for 28 days in the cyclophosphamide-treated group provided significant protection except with respect to plasma LH. These results suggest the possibility of an indirect action of cyclophosphamide at the level of the ovary.

17-Hydroxysteroid Dehydrogenases↗
PubMedDate not supplied

Congener-specific polychlorinated biphenyl-induced cell death in human kidney cells in vitro: potential role of caspase.

Polychlorinated biphenyls (PCBs) are among the most widespread and persistent pollutants in the global environment. Coplanar and noncoplanar PCBs have been shown to cause congener-specific apoptosis mediated neurotoxicity in rats. Very few, if any, such studies have been reported on human renal cell toxicity. The authors report here caspase-dependent or caspase-independent renal toxicity, as measured by apoptotic death induced by PCBs, depending on the planarity of congeners PCB-77 (coplanar) and PCB-153 (noncoplanar) in human kidney cells (HK2) in vitro. The authors have combined morphological and biological techniques to discover the relevance of apoptosis in renal proximal tubule cell death induced by these two PCB congeners. Treatment with both PCB congeners caused accelerated apoptosis in a time- and concentration-dependent manner. Based on our findings using human kidney (HK2) cells, there was more apoptosis-mediated loss of cell viability by non-ortho-substituted PCB-77 when compared to PCB-153. A significant increase of caspase-3 expression through immunoblot studies showed the involvement of apoptosis by PCB-77 compared to none by PCB-153. The broad-spectrum caspase inhibitor z-VAD-fmk showed increased cell death when treated by PCB-153, but not by PCB-77, confirming that caspase inhibitor induced a switch in the mode of cell death. It is reasonable to assume that apoptotic cell death in the renal proximal tubule cells treated by PCBs may have both caspase-dependent and caspase-independent pathways.

Amino Acid Chloromethyl Ketones↗
PubMedDate not supplied

Assessment of hearing level by means of the acoustic reflex.

It has been suggested that hearing level might be assessed by comparing the acoustic reflex thresholds (ARTs) for two modes of stimulation: by pure tones alone and by a combination of two pure tones, one of which is used as a "preactivator." Using an extrapolatory method for determining the reflex thresholds, 35 subjects (17 normal hearing and 18 hearing impaired) were used to test the above hypothesis. For the individual frequencies 75% of the hearing levels estimated from the ARTs lay within +/- 10 dB of the true threshold, and 97% within +/- 20 dB. However, although the method does appear to be more accurate than the Niemeyer and Sesterhenn method of estimating hearing loss from the ARTs for pure tones and noise bands, it has limitations due to the high levels of preactivating tone required, and the number of stimuli it is necessary to use. Some possible refinements are suggested that might improve the clinical applicability of the technique.

Adult↗
PubMedDate not supplied

Are Muslim women less susceptible to oncogenic human papillomavirus infection? A study from rural eastern India.

Muslim women are known to have lower incidences of cervical cancer and/or human papillomavirus (HPV) infection. Here we aim to determine any association that may be present between the oncogenic HPV16/18 infections and abnormal cytological lesions along with demographic and other attributes among Indian Muslim women (n = 478) and compare with the neighboring Hindus (n = 534) from a prospective cohort study. Agewise distribution of both subject-groups is similar. HPV16/18 infection is present in 9.6% Muslims and 7.5% Hindu women. Jointly atypical cells of undetermined significance (a typical cells of undetermined significance) and HPV16/18 are present in seven Muslim and two Hindu women. No high squamous intraepithelial lesions or cervical cancer is detected at the baseline. HPV16/18 infections show trends that varied with age, a nonlinear trend among Muslim women. In Hindu women the prevalence is highest at age < or =24 years, which linearly drops with increasing age. Abnormal cytology increases significantly in both religion-groups with increasing age. The data show that these Indian Muslim women are equally susceptible to HPV16/18 infection and for the development of abnormal cytology. There is a paucity in epidemiological data, which justifies the need to screen women of all religions for cervical cancer (that includes oncogenic HPV testing).

Adult↗
PubMedDate not supplied

Magnetic resonance imaging-based prospective detection of intraperitoneal human ovarian carcinoma xenografts treatment response.

The feasibility of applying magnetic resonance imaging (MRI) for conducting prospective studies of intraperitoneal (i.p.) tumor treatment response to chemotherapy and resultant effects on survival in human ovarian carcinoma/nude mouse orthotopic xenograft models was evaluated. Female nude mice were implanted i.p. with either NMP-1 or SKOV-3ip. human ovarian carcinoma cells on day 0. Initial T2-weighted magnetic resonance (MR) images of the abdomens of NMP-1-implanted mice were obtained on day 7 to confirm the presence of nascent tumors; similar confirmations were made on day 14 with mice bearing SKOV-3ip. xenografts. On the initial imaging days, a multiple-dose regimen of cisplatin (CDDP; qd7 x3) was commenced, using 4 or 6 mg/kg treatments with the NMP-1 model and using 6 mg/kg treatments with the SKOV-3ip. model. Mice were reimaged multiple times, 2 days following each CDDP injection and at later times as well, depending on host survival. The images for each mouse from the last imaging day (day 30 for NMP-1, day 44 for SKOV-3ip.) were used in a blinded fashion to attempt to visually distinguish control from treated mice and to determine whether MRI could predict a survival benefit. For SKOV-3ip. mice, ten out of ten mice were correctly segregated into the control or the CDDP treatment group based solely on these blinded, nonquantified MR results. In this model, the 6 mg/kg multiple-dose regimen achieved a modest response, improving life span by approximately 24%. However, for the NMP-1 mice, only six out of nine evaluable mice were correctly segregated into the control or one of the treatment groups by similar MRI criteria, a virtually random distribution; further, neither CDDP treatment regimen achieved a significant improvement in survival in this model. In another study, NMP-1-implanted mice were treated on day 7 after tumor implantation with a single injection of a hyaluronic acid-paclitaxel copolymer. Control and treated mice were MR imaged on day 28, which revealed marked reductions in tumor burden in treated mice, correlating well with a subsequently observed improved survival of approximately 40%. Our results suggest that MRI can be used to serially and noninvasively monitor treatment response and predict ongoing treatment effects on survival.

Animals↗
PubMedDate not supplied

Micronuclear and macronuclear sequences of a Euplotes crassus gene encoding a putative nuclear protein kinase.

The sequences of a 1.8-kbp macronuclear DNA molecule (V3), and the majority of its micronuclear counterpart, are reported. The macronuclear V3 DNA molecule contains an open reading frame that is interrupted by a single intron, while the micronuclear copy is interrupted by four internal eliminated sequences, one of which is located within the intron. The predicted protein product of the macronuclear V3 gene is a 471-amino acid polypeptide that is very similar to a group of protein-serine/threonine kinases from both plant and animal species, some of whose members appear to be involved in cell cycle or growth control.

Amino Acid Sequence↗
PubMedDate not supplied

Conjugation-specific genes in the ciliate Euplotes crassus: gene expression from the old macronucleus.

Following mating or conjugation, the hypotrichous ciliate Euplotes crassus undergoes a massive genome reorganization process. While the nature of the rearrangement events has been well studied, little is known concerning proteins that carry out such processes. As a means of identifying such proteins, differential screening of a developmental cDNA library, as well as construction of a cDNA subtraction library, was used to isolate genes expressed only during sexual reproduction. Five different conjugation-specific genes have been identified that are maximally expressed early in conjugation, during the period of micronuclear meiosis, which is just prior to macronuclear development and the DNA rearrangement process. All five genes are retained in the mature macronucleus. Micronuclear, macronuclear, and cDNA clones of one gene (conZA7) have been sequenced, and the results indicate that the gene encodes a putative DNA binding protein. In addition, the presence of an internal eliminated sequence in the micronuclear copy of the conZA7 gene indicates that this conjugation-specific gene is transcribed from the old macronucleus.

Amino Acid Sequence↗
PubMedDate not supplied

Haplotyping in pedigrees via a genetic algorithm.

Genome-wide screening for localization of disease genes necessitates the efficient reconstruction of haplotypes of members of a pedigree from genotype data at multiple loci. We propose a genetic algorithmic approach to haplotyping and show that it works fast, efficiently and reliably. This algorithm uses certain principles of biological evolution to find optimal solutions to complex problems. The optimality criterion used in the present problem is the minimum number of recombinations over possible haplotype configurations of members of a pedigree. The proposed algorithm is much less demanding in terms of data and assumption requirements compared to the currently used likelihood-based methods of haplotype reconstruction. It also provides multiple optimal haplotype configurations of a pedigree, if such multiple optima exist.

Algorithms↗
PubMedDate not supplied

Vanadium: a modifier of drug-metabolizing enzyme patterns and its critical role in cellular proliferation in transplantable murine lymphoma.

Vanadium, as ammonium monovanadate, has been found to stimulate tumour cell proliferation in mice bearing a transplantable ascitic lymphoma. Markers including microsomal cytochrome P-450, UDP-glucuronyltransferase and cytosolic glutathione-S-transferase showed substantial alterations in a dose-responsive manner with vanadium administration when compared to the controls. Stimulation of tumour progression is also reflected by increased tumour cell count and decreased survival of the host.

Animals↗