Haldane's solution of the Luria-Delbrück distribution.
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Bacteria↗
Biomedical subjects
S Sarkar
Publications and source records attributed to S Sarkar.
Intravenous drug users--a new high-risk group for HIV infection in India.
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Adult↗
Localization of basic fibroblast growth factor mRNA in melanocytic lesions by in situ hybridization.
Basic fibroblast growth factor (bFGF) is a mitogen for normal human melanocytes and keratinocytes in culture. Experiments in vitro suggest that keratinocytes supply bFGF to melanocytes through a paracrine mechanism and that the aberrant expression of bFGF in melanomas confers growth independence from bFGF-producing cells. To determine whether bFGF is expressed in vivo, we examined a series of benign and malignant melanocytic lesions in situ using bFGF riboprobes on tissue sections, and correlated bFGF expression with histologic phenotype. Seventeen melanocytic neoplasms were studied, including four common acquired nevi, four dysplastic nevi, four primary malignant melanomas, and five metastatic melanomas. Nevic cells in benign intradermal nevi showed low signal intensity (1+), whereas compound and dysplastic nevi showed 2+ to 3+ expression in the junctional nevic cell population and 1+ expression in the dermal nevic cell population. Melanocytes in primary melanomas had intermediate (2+) and those in metastatic melanomas had low (1+) levels of bFGF gene transcripts. Fibroblasts expressed high levels (3+) and epidermal and adnexal keratinocytes moderate (2+) levels of bFGF in all cases studied. Basic FGF expression in endothelial cells, known to produce and respond to this growth factor in vitro, was lower than that in the fibroblast and keratinocyte cell population and, in 10 of 17 cases, no bFGF mRNA was detectable. This study shows that bFGF is expressed in nevomelanocytes in vivo in all melanocytic lesions studied and thus cannot be used as a marker for transformation. The presence of bFGF gene transcripts in the various dermal cell types and in keratinocytes suggests that it may act as an autocrine and paracrine growth factor in regulating cellular proliferation in the skin.
Fibroblast Growth Factor 2↗
Intragenic sequences affect the expression of the gene encoding glial fibrillary acidic protein.
We show that the expression of the gene encoding glial fibrillary acidic protein (GFAP) gene is affected by at least three cis-acting elements. A positive regulatory element that is located between nucleotides -1,631 and -1,479 can confer cell type-specific expression on a heterologous gene. A second regulatory element is located between nucleotides -97 and -80. The third is a negative regulatory element that is located within the first intron of the gene. Deletion of this element activates GFAP expression in HeLa cells, and affects promoter function in glioma cells.
Animals↗
Regulation of expression of glial filament acidic protein.
The regulation of cell type-specific expression of the gene encoding glial filament acidic protein (GFAP) was examined by introducing various deletion mutants of the gene into GFAP-expressing (U251 human astrocytoma) and non-expressing (HeLa) cell lines, and measuring their transcriptional activity in an RNAase protection assay. The expression of GFAP is influenced by a number of cis-acting elements. A domain that resides between nucleotides -1631 and -1479 can confer cell type-specific expression when coupled to a heterologous gene. We also present evidence for the existence of a negative regulatory element that resides within the first intron of the GFAP gene.
Animals↗
An operational study on implementation of oral rehydration therapy in a rural community of West Bengal, India.
An operational study of a 3-tier strategy for implementation of oral rehydration therapy (ORT) was conducted in a block of West Bengal with 216,825 population through the existing health services facilities. All the grassroot level, health workers including their supervisors at various levels were trained regarding the management of patients of diarrhoea with mild to moderate degree of dehydration, by ORT. Another block in the same district with similar demographic features where this intervention was not provided served as control. After 22 months of observation, it was evident that despite adequate training, the performance of Community Health Guides (CHGs) and Anganwadi Workers (AWWs) was not encouraging because of the low utilization of both home available fluids (32.0%) and oral rehydration solution (18.0%) in the study area. Similarly, diarrhoea associated mortality could not be reduced significantly. Lack of motivation and failure to maintain sustained level of skill by the CHGs and AWWs constitute the major bottlenecks for the successful implementation of the programme at the community level.
Child, Preschool↗
Zinc protection against lipid peroxidation from cadmium.
Effect of zinc and cadmium on lipid peroxidation and catalase activity in liver, heart, brain and testis was determined in order to characterise the interaction of zinc with cadmium. Zinc and cadmium both increased lipid peroxidation significantly in the tissues studied. In animals pretreated with zinc prior to cadmium administration, significant decrease in lipid peroxidation in liver was observed. Lipid peroxidation was not affected significantly in testis but a significant increase was observed in heart and brain tissues. Catalase activity in testis increased significantly by zinc treatment with or without cadmium administration.
Animals↗
Hypomagnesemic hypocalcemia as a cause of persistent upper airway obstruction in acute bacterial tracheitis.
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Acinetobacter Infections↗
Empyema thoracis.
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Anti-Bacterial Agents↗
A high affinity Ca2(+)-ATPase on the surface membrane of Leishmania donovani promastigote.
A Ca2(+)-dependent ATP-hydrolytic activity was detected in the crude membrane ghost of the promastigote or vector form of the protozoal parasite Leishmania donovani, the pathogen responsible for kala azar. The Ca2(+)-ATPase was purified to apparent homogeneity after solubilization with deoxycholate. The enzyme consists of two subunits of Mr = 51,000 and 57,000 and has an apparent molecular weight of 215,000 +/- 12,000. The enzyme activity is exclusively dependent on Ca2+, and the pure enzyme can hydrolyze 1.6 mumol of ATP/min/mg of protein. The apparent Km for Ca2+ is 35 nM, which is further reduced to 12 nM in the presence of heterologous calmodulin. The enzyme is sensitive to vanadate, but is insensitive to oligomycin and ouabain. The enzyme is strongly associated with the plasma membrane and has its catalytic site oriented toward the cytoplasmic face. The enzyme spans across the plasma membrane as surface labeling with radioiodine shows considerable radioactivity in the completely purified enzyme. The localization and orientation of this high affinity, calmodulin-sensitive Ca2(+)-ATPase suggest some role of this enzyme in Ca2+ movement in the life cycle of this protozoal parasite.
Adenosine Triphosphate↗
Ca2(+)-dependent interactions between the C-helix of troponin-C and troponin-I. Photocross-linking and fluorescence studies using a recombinant troponin-C.
We have used in vitro mutagenesis to synthesize in Escherichia coli a recombinant rabbit skeletal troponin-C (designated as TnC57) in which Cys-98 was replaced with leucine, and Ala-57 in the C-helix of the N-terminal domain was replaced with cysteine. TnC57 labeled with the bifunctional photocross-linker benzophenone-4-maleimide could be photocross-linked with troponin-I in both the binary complex with troponin-I and in the ternary complex with troponin-I and troponin-T. The fluorescence lifetime of TnC57 labeled with the probe N-iodoacetyl-N'-(5-sulfo-1-naphthyl)ethylenediamine decreased from 13.2 +/- 0.1 to 11.8 +/- 0.1 ns when Ca2+ bound to the low affinity triggering sites. Complexation with either troponin-I or both troponin-I and troponin-T resulted in significant increases in this lifetime both in the absence and the presence of Ca2+. In either the binary or the ternary complex, this lifetime increased from 15.5 to 18.0 ns upon Ca2+ binding to the low affinity sites. Complementary acrylamide-quenching studies yielded results that are consistent with the fluorescence lifetime results. Our results show that the C-helix of troponin-C interacts with troponin-I, in confirmation of recent zero-length cross-linking results (Leszyk, J., Grabarek, Z., Gergely, J., and Collins, J.H. (1990) Biochemistry 29, 299-304). Moreover, they are in support of a model (Herzberg, O., Moult, J., and James, M.N.G. (1986) J. Biol. Chem. 261, 2638-2644) in which the binding of Ca2+ to the triggering sites in the N-terminal domain of troponin-C results in the movement of the B- and C-helices away from the central helix, thereby exposing a putative hydrophobic binding site for troponin-I.
Animals↗
The human embryonic myosin heavy chain. Complete primary structure reveals evolutionary relationships with other developmental isoforms.
We have isolated a single 6021-nucleotide cDNA fragment encoding the full length of the myosin heavy chain (MHC) isoform initially expressed in developing human limb muscle. The corresponding transcript is expressed in fetal, but not adult, human muscle, and the corresponding gene maps to human chromosome 17. Comparison of the full length nucleotide sequence with that of the orthologous rat gene transcript reveals 74, 90, and 80% similarities in the 5'-untranslated, coding, and 3'-untranslated regions, respectively. To precisely quantitate the degree of nucleotide sequence divergence between the human embryonic and other developmentally regulated MHC gene transcripts, we utilize the algorithm of Perler et al. (Perler, F., Efstratiadis, A., Lomedico, P., Gilbert, W., Kolodner, R. & Dodgson, J. (1980) Cell 20, 555-566) and make use of the codon-for-codon register attainable in alignments of the MHC rod encoding cDNA fragments. The results allow reconstruction of the order and relative timing of certain gene duplication events involved in the evolution of the multimembered mammalian MHC loci. By this analysis, the principal sarcomeric MHC gene expressed in the 14-day chick embryo is shown to be more distantly related to the mammalian embryonic MHC genes than to those expressed peri- and postnatally. Attention is focused on regional patterns of MHC sequence conservation, ordered with reference to the topology of our phylogenetic tree. We present a composite map depicting the deduced evolutionary age of various primary structural subdomains of the human embryonic MHC.
Algorithms↗
Mortality and morbidity of primary pharyngogastric anastomosis following circumferential excision for hypopharyngeal malignancies.
Seventy-five patients underwent gastric transposition for replacement of the pharyngoesophagus. These patients had primary or recurrent malignant tumors of the hypopharynx, postcricoid region, and cervical esophagus. The operative procedure consisted of a transhiatal esophagectomy and gastric pull-up to establish gastrointestinal continuity, with a unilateral or bilateral neck dissection where indicated. Seven patients died, a mortality rate of 9.33%. The average hospital stay of uncomplicated cases was 18 days and for complicated cases was 40 days. Immediate restoration of oral intake was achieved in 70.6% of patients. We conclude that gastric transposition after circumferential laryngopharyngeal excision is a procedure with low mortality and acceptable morbidity leading to early relief of dysphagia.
Adult↗
Complications following surgery for cancer of the larynx and pyriform fossa.
The hospital records of patients undergoing major surgery for cancer of the larynx and hypopharynx at the Tata Memorial Hospital, Bombay, from 1981 to 1985 were reviewed. Different variables were correlated with the incidence of major complications and were analysed to find out significant factors contributing to increased complication rates. Complications included wound infection, pharyngocutaneous fistulae, flap necrosis, carotid blowout, and neo-esophageal stenosis. Postoperative deaths and delayed fatalities were also recorded. The overall fistulae rate was 34.7%, and wound infection occurred in 28% of patients. Prior radiotherapy and the need for pharyngeal reconstruction were found to be significant in determining postsurgical complications. Age, sex, site, stage, cartilage and soft tissue infiltration, preoperative tracheostomy, involvement of resection margins by tumor, and the dose of radiotherapy were not found to influence the complication rates.
Adult↗
Complementation of coat protein-defective TMV mutants in transgenic tobacco plants expressing TMV coat protein.
Transgenic tobacco plants (Nicotiana tabacum cv. Xanthi) which express tobacco mosaic virus (TMV) U1 strain coat protein (CP) can complement both the assembly and the long-distance spread of CP-defective (DT1) or coat proteinless (DT1G) mutants of TMV. Both mutants arose spontaneously from PM2 and exist only as unencapsidated RNA in the inoculated leaves of control tobacco plants, where they are unable to form virus particles or to spread systemically. TMV CP expressed in transgenic tobacco plants [CP+ line 3404; P. Powell Abel, R. S. Nelson, B. De, N. Hoffman, S. G. Rogers, R. T. Fraley, and R. N. Beachy, 1986, Science 232, 738-743] was able to package some of either mutant viral RNA into TMV-like particles in vivo and resulted in the long-range spread of infection. In vivo encapsidated DT1 RNA was recovered and reinoculated onto control or new CP+ transgenic tobacco plants. Localized infection of control plants confirmed that no RNA recombination or reversion of the mutant RNA to wild-type had occurred during passage in the first CP+ plant. In contrast, encapsidated DT1 RNA was unable to produce even local infection in CP+ transgenic plants confirming that CP-mediated protection operates during the early stages of virus infection, including particle uncoating. By positive complementation, these results also confirm that TMV CP is required for the long-distance spread of infection.
Blotting, Northern↗
True hermaphroditism: a report of two cases.
Two cases with true hermaphroditism are described. A 2 year old child presented with ambiguous genitalia, and had bilateral ovotestis in the labioscrotal folds. A 20 year old boy presented with grade V gynaecomastia and periodical bleeding as well as seminal discharge after phallic stimulation; he had right sided ovotestis, normal size uterus, left ovary and hypoplastic fallopian tubes. Male gender was assigned to both. Cytogenetically both were 46XX. Gonadectomy was done in both the cases. Bilateral mastectomy and hysterectomy was done in the second case.
Adult↗
Outbreak of Salmonella worthington meningitis & septicaemia in a hospital at Chandigarh (north India).
During August 1988 an outbreak of hospital acquired infection due to S. worthington has been reported at the Nehru Hospital, Postgraduate Institute of Medical Education and Research, Chandigarh. A total of seven neonates presented with the clinical features of meningitis and septicaemia during this outbreak and six babies died. S. worthington was isolated from blood and cerebrospinal fluid respectively. The same strains were isolated from the baby warmer mattress, baby cot, suction machine bottle and wall of the fridge. Samples from doctors, nurses and apparently healthy babies born during this period did not grow the above organism. This appears to be the first report on S. worthington in human beings from India. The outbreak was controlled by thorough cleaning and fumigation. The organisms were also mostly sensitive to antibiotics used, in contrast to the multiple drug resistant pattern reported from elsewhere.
Cross Infection↗
Human embryonic myosin heavy chain cDNA. Interspecies sequence conservation of the myosin rod, chromosomal locus and isoform specific transcription of the gene.
A 3.6 kilobase cDNA clone coding for the human embryonic myosin heavy chain has been isolated and characterized from an expression library prepared from human fetal skeletal muscle. The derived amino acid sequence for the entire rod part of myosin shows 97% sequence homology between human and rat and a striking interspecies sequence conservation among the charged amino acid residues. The single copy gene is localized to human chromosome 17 and its expression in fetal skeletal muscle is developmentally regulated. The sequence information permits the design of isoform-specific probes for studies on the structure of the gene and its role in normal and defective human myogenesis.
Amino Acid Sequence↗