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Biomedical subjects

G Chandra

Publications and source records attributed to G Chandra.

At least 37 records · Page 2Linked to original sources
PubMed1996

125I aqueous waste volume reduction at a pharmaceutical research laboratory.

A wide variety of radioactive waste is generated by pharmaceutical research. One particularly high volume low specific activity waste stream produced by a research and development facility is aqueous 125I waste. This waste is generally held for decay and released to the sanitary sewer when the activity is low enough to ensure that concentrations are well below the appropriate regulatory limits. However, the large volume of this particular waste stream rapidly exhausted available space to store it for decay. This study investigated safe, inexpensive, and efficient methods for removing 125I from the aqueous waste, with the goal of implementing a practical process for concentrating the activity and thus reducing the stored volume. The implemented treatment (volume reduction) process used commercially available low cost activated carbon/particulate filters and inexpensive resin beds manufactured in-house. The much smaller volumes of spent filters and resin beds are then held for decay and eventual incineration. This technique has proven an effective means for managing this high volume waste stream.

Adsorption↗
PubMed1995

Characterization of human E4BP4, a phosphorylated bZIP factor.

In this report we described the isolation of transcription factor E4BP4 by lambda gt11 expression cloning using a probe containing the CRE/ATF-like sequence located between -2764 bp and -2753 bp in the upstream regulatory region for the human IL-1 beta gene. DNaseI protection, gel mobility shift analysis, and cotransfection studies were performed to investigate the binding and functional properties of E4BP4 using IL-1 beta promoter sequences. By DNaseI footprinting, a protection pattern was generated over the CRE/ATF-like site and the flanking sequences by bacterially produced E4BP4. Competition experiment by gel shift assay indicated that E4BP4 bound specifically to CRE/ATF-like site, not NF kappa B-like site. In cotransfection studies, E4BP4 repressed promoter activity and this repression was mediated through the CRE/ATF-like site. Mutational analysis of E4BP4 suggested that the DNA binding as well as repression activities required leucine heptad repeat domain. Analysis of E4BP4 produced in Escherichia coli and Sf9 cells infected with recombinant baculovirus indicated that baculovirus produced protein showed enhanced binding to the CRE/ATF-like site compared to the E. coli-produced protein. Analysis of posttranslational modifications indicated that E4BP4 produced in Sf9 cells was phosphorylated and this phosphorylation was important for the DNA binding activity of E4BP4.

Activating Transcription Factor 2↗
PubMed1995

Cyclic AMP signaling pathways are important in IL-1 beta transcriptional regulation.

An intact cAMP response element (CRE) in the upstream regulatory sequence of IL-1 beta (-2755/-2762) has been shown to be essential for maintaining full IL-1 beta inducibility following treatment with LPS, PMA, or TNF-alpha. In the present study, using the recombinant plasmid pIL-1(4.0 kb)-chloramphenicol acetyltransferase, containing 4.0 kb of the IL-1 beta upstream regulatory sequence, we have demonstrated that dibutyryl cAMP treatment alone is capable of induction. Due to the critical nature of the CRE for the induction of IL-1 beta transcription, an effort was made to determine the importance of the cAMP signaling pathway(s) by determining whether CRE binding protein (CREB) and other CREB/activating transcription factor (ATF) family members that responded to cAMP were associated with the DNA-protein complex that forms at this site. Nuclear extracts prepared from LPS-treated THP-1 5A cells were fractionated by ammonium sulfate precipitation and heparin-Sepharose chromatography, and the resulting fractions were characterized in electrophoretic gel mobility shift assays. These purification steps resulted in an approximately 100-fold enrichment of the proteins binding to the CRE site. Western blot analysis of isolated fractions, using CREB- and ATF-1-specific Ab showed an increased level of these proteins in the enriched fractions. Tryptic digest and DNase I protection studies showed the presence of CREB protein in the complex at the CRE site. Supershift electrophoretic gel mobility shift assays and immunoprecipitation analysis provided further evidence that both CREB and ATF-1 are present in the complex. In addition, an increase in CREB phosphorylation was observed when THP-1 5A cells were treated with dibutyryl cAMP, LPS, or both. These studies confirm the importance of a cAMP signaling pathway(s) in the regulation of IL-1 beta at the transcriptional level.

Base Sequence↗
PubMed1995

A cyclic adenosine 3',5'-monophosphate signal is required for the induction of IL-1 beta by TNF-alpha in human monocytes.

IL-1 beta is a cytokine generally considered to be a major component involved in the pathogenesis of rheumatoid arthritis and other inflammatory diseases. Of the agents found in high concentrations in inflamed rheumatoid arthritis joints, TNF-alpha is among the most strongly implicated as an in vivo inducer of IL-1 beta. Here we report that in human PBMC and in a stable transfectant of the promonocytic cell line, THP-1, TNF-alpha indeed appears to be an inducer of IL-1 beta production, but only in the presence of dibutyryl cAMP or agents such as the PG that elevate intracellular cAMP levels. This TNF-alpha/cAMP pathway regulates IL-1 beta production at the level of transcription and requires a cAMP response element located between -2762 and -2755 bp in the upstream regulatory sequence of IL-1 beta. Because PG, which are known to elevate cAMP levels in vivo, and TNF-alpha are both found in significant quantities in the synovial fluid of rheumatoid arthritis joints, the observed synergistic up-regulation in IL-1 beta synthesis by TNF-alpha/cAMP (PG) may provide valuable insight into the potential pathways involved in the continuous production of IL-1 beta in the chronically inflamed joint.

Alkaline Phosphatase↗
PubMed1995

Molecular cloning of Indian tomato leaf curl virus genome following a simple method of concentrating the supercoiled replicative form of viral DNA.

DNA-A and DNA-B components of the genome of a whitefly transmitted virus causing yellowing and leaf curl in tomato (ITLCV) were cloned following a simple procedure for isolation of the double stranded replicative form of viral DNA from infected tomato plants. The method is based on extraction of total DNA from infected plants followed by concentration of the double stranded replicative form of viral DNA by an alkaline denaturation procedure identical to that used for isolation of plasmid DNA from Escherichia coli. The attempted cloning of DNA showed that 95% of the transformants contained plasmids with an insert of either DNA-A (2.75 kb) or DNA-B (2.55 kb). Cloned DNA-A and DNA-B when used as probes could detect DNA-A/DNA-B in total nucleic acid obtained from fresh diseased tissue. Both DNA-A and DNA-B are needed for infection and they have a common region of 166 bases with about 94% nucleotide sequence homology, a characteristic of all bipartite geminiviruses. Comparison of the amino acid sequence of the putative coat protein product of ITLCV with some other mono- and bipartite geminiviruses revealed a maximum of 86% homology with Indian cassava mosaic virus.

Amino Acid Sequence↗
PubMed1995

Short report: peak period of filarial transmission.

This study was designed to determine the peak period of infective mosquito biting and thus the greatest potential for filarial transmission to occur. It was found that biting density, natural infection, and infectivity rates of Culex quinquefasciatus were significantly higher in the third quadrant of the night (from midnight to 3:00 AM) than at other times. This was true in both an urban and a rural environment. Avoidance of mosquito bite by any means during this time period might reduce and limit filarial transmission to a great extent.

Animals↗
PubMed1995

Susceptibility status of Phlebotomus argentipes to DDT, dieldrin and malathion in Hoogly, West Bengal.

Susceptibility tests were carried out with DDT (4%), dieldrin (0.4%) and malathion (5%) using the WHO test kits against Phlebotomus argentipes sandflies collected from Dankuni, situated in Hoogly district, 21 km from Calcutta, West Bengal. P. argentipes was found to be susceptible to all the three insecticides tested. LT 50 was calculated to be 10.6 minutes, 10.2 minutes and 2.8 minutes for DDT, dieldrin and malathion against the flies.

Animals↗