Search PubMed⌕ Search

Biomedical subjects

S Ganguly

Publications and source records attributed to S Ganguly.

At least 19 recordsLinked to original sources
PubMed1992

Characterization of cDNA for the large subunit of the transcription initiation factor TFIIF.

At least six chromatographically resolvable general transcription factors may participate in accurate initiation by RNA polymerase II in HeLa cell-derived systems. TFIIF (also termed FC, RAP30/74 and beta/gamma) can bind directly to RNA polymerase II in solution and decrease the affinity of RNA polymerase II for nonspecific DNA. From studies on the kinetics of transcription initiation, on the composition of transcription initiation complexes fractionated by acrylamide gel electrophoresis, and on template competition experiments, TFIIF is known to act at an intermediate stage in initiation complex formation. It acts after TFIID firmly associates with DNA, but coincidentally with or immediately after RNA polymerase II binding to DNA, and before the recruitment of factor TFIIE. TFIIF may or may not have DNA helicase activity. The small subunit (RAP30) of TFIIF has been cloned and shows some amino-acid sequence homology to bacterial sigma factors. We have partially sequenced the RAP74 protein from purified HeLa cells, cloned its complementary DNA and shown that its translation product can interact with RAP30 in vitro as well as in vivo. The cDNA predicts an amino-acid sequence that lacks obvious DNA or RNA helicase motifs. It has regions rich in charged amino acids, including segments containing a higher content of acidic amino acids than are found in strong transcriptional activators such as VP16.

Amino Acid Sequence↗
PubMed1992

The core protein of epican, a heparan sulfate proteoglycan on keratinocytes, is an alternative form of CD44.

Epican, a heparan sulfate proteoglycan, was recently identified on the surface of keratinocytes with the aid of a monoclonal antibody to its core protein. Using that antibody to screen a human keratinocyte cDNA library, a clone encoding the entire epican core protein was selected and sequenced. The core protein of epican is a form of CD44. The deduced protein sequence of 699 amino acids has a novel 339 amino acid domain inserted into the proximal extracellular domain of the standard, leukocyte form of CD44. The additional domain adds a number of potential N- and O-linked glycosylation sites and two proteolysis sites to this form of CD44.

Amino Acid Sequence↗
PubMed1992

Hepatoprotective activity of Azadirachta indica leaves on paracetamol induced hepatic damage in rats.

Effect of A. indica leaf extract on serum enzyme levels (glutamate oxaloacetate transaminase, glutamate pyruvate transaminase, acid phosphatase and alkaline phosphatase) elevated by paracetamol in rats was studied with a view to observe any possible hepatoprotective effect of this plant. It was interesting to observe that serum enzyme levels were much elevated in paracetamol induced animals than in those receiving a combination of paracetamol and lead extract. It is stipulated that the extract treated group was protected from hepatic cell damage caused by paracetamol induction. The findings were further confirmed by histopathological study of liver.

Acetaminophen↗
PubMed1992

Ontogenetic and comparative analysis of LDH isozymes in the three species of Indian major carp.

Expression patterns of lactate dehydrogenase (LDH) isozyme were investigated in embryonic and post embryonic stages of Labeo rohita, Cirrhinus mrigala and Catla catla using starch gel electrophoresis. Species specific and differential enzyme locus (gene) expression patterns were found in LDH up to 18th hr of study. The isozyme up to 36th hr after fertilization seemed to be completely active and showed electrophoretic patterns very similar to those of the adults. Comparative analysis of the isozyme of the three species permitted species identification even during the embryonic stages when it is impossible to identify on morphological characters only. Also, the genetic studies indicated different taxonomical and evolutionary histories of the species.

Animals↗
PubMed1991

A contingent replication assay for the detection of protein-protein interactions in animal cells.

We have developed a sensitive and rapid assay system termed the contingent replication assay (CRA) for selecting cDNAs with desired functional properties from a cDNA library. The system functions in animal cells and permits enrichment of the desired cDNA in small-scale and convenient experiments. The assay can be used for the enrichment of proteins that activate transcription from conditional enhancers, bind to specific DNA sequences, or interact with target proteins of interest. In this communication we report the application of this assay to study protein-protein interactions in animal cells.

Animals↗
PubMed1991

Identification of cis sequences controlling efficient position-independent tissue-specific expression of human major histocompatibility complex class I genes in transgenic mice.

We previously reported that genomic major histocompatibility complex class I human leukocyte antigen (HLA)-B7 gene constructs with as little as 0.66 kb of 5'- and 2.0 kb of 3'-flanking DNA were expressed efficiently and appropriately in transgenic mice. To identify and characterize the relevant cis-acting regulatory elements in more detail, we have generated and analyzed a series of transgenic mice carrying native HLA-B7 genes with further 5' truncations or intronic deletions and hybrid constructs linking the 5'-flanking region of B7 to a reporter gene. We were unable to detect a specific requirement for sequence information within introns 2 to 7 for either appropriate constitutive or inducible class I expression in adult animals. The results revealed the presence of cis-acting regulatory sequences between -0.075 kb and -0.66 kb involved in driving efficient copy number-dependent constitutive and gamma interferon-enhanced tissue-specific expression. The region from -0.11 to -0.66 kb is also sufficient to prevent integration site-specific "position effects," because in its absence HLA-B7 expression is frequently detected at significant levels at inappropriate sites. Conserved sequence elements homologous to the H-2 class I regulatory element, or enhancer A, and the interferon response sequence are located between about -151 and -228 bp of the B7 gene. Our results also indicate the existence of sequences downstream of -0.11 kb which can influence the pattern of tissue-specific expression of the HLA-B7 gene and the ability of this gene to respond to gamma interferon.

Animals↗
PubMed1991

Hypoglycemic and antihyperglycemic effect of leaves of Vinca rosea linn.

Oral administration of water fraction of alcoholic extract of leaves of Vinca rosea (fam. apocynaeceae) led to marked lowering of blood glucose level in normal and streptozotocin induced diabetic rats. The hypoglycemic effect of the fraction was comparable with that of tolbutamide.

Administration, Oral↗
PubMed1991

Recent outbreak of chloramphenicol resistant typhoid fever in West Bengal.

Forty patients admitted with typhoid fever from 1-1-1990 to 31-3-1990 were studied. The clinical features differed from the classical clinical profile. Thirty cases (75%) did not respond to chloramphenicol. Gentamicin, nitrofurantoin, nalidixic acid, kanamycin, cephalexin and norfloxacin were tried according to the sensitivity pattern. But response was variable. Ciprofloxacin was used in 18 cases which failed to respond to one of the above drugs. The result was quite satisfactory with minimal side-effects.

Anti-Infective Agents↗
PubMed1991

Use of intravenous amrinone in the short-term management of refractory heart failure in pregnancy.

The use of amrinone, a cardiac inotropic agent with vasodilatory properties, has not been described in human pregnancy. We report the use of amrinone in a woman at 18 weeks' gestation who had congestive heart failure secondary to bacterial endocarditis. Although her cardiac output and congestive heart failure improved, she developed hypoxemia, metabolic acidosis, and premature ventricular contractions. These effects resolved when the amrinone treatment was stopped.

Acidosis, Lactic↗
PubMed1990

Detection of preferential NRAS mutations in human male germ cell tumors by the polymerase chain reaction.

We have studied 31 male germ cell tumors (GCTs) for probable mutations in codons 12, 13, and 61 of HRAS, KRAS, and NRAS oncogenes using the polymerase chain reaction. Twenty of the thirty-one tumors exhibited NRAS gene mutations, 14 in codon 61, and six in codon 12, whereas no mutations were detected in HRAS and KRAS genes. The NRAS mutations were equally prevalent in seminomatous and nonseminomatous GCTs. Thus 13 of 22 seminomas, six of seven embryonal carcinomas, and one of two mixed tumors exhibited mutations. Two non-seminomatous tumors (an embryonal carcinoma and a yolk sac/teratoma) had mutations in both codons 12 and 61. The high frequency of NRAS mutations observed in the present study suggests that NRAS gene products may play an important role in growth regulatory functions of premalignant and malignant germ cells.

DNA Mutational Analysis↗
PubMed1990

Clinical aspects of centipede bite in the Andamans.

Clinical aspects of centipede bite as seen in the Andamans are reported. Centipede bite produces excruciating local pain and burning. Local bleeding is common but transient. Occasionally local infection or necrosis develops. Constitutional upset occurs in a small minority. Centipede bites are never fatal and pain-relief is the cornerstone of treatment.

Adolescent↗
PubMed1989

Multiple enhancer-like sequences in the HLA-B7 gene.

Enhancer-like sequences have previously been identified in the promoter region of the mouse major histocompatibility complex (MHC) class I genes. We have screened for such sequences in and around a human MHC class I gene, HLA-B7. Various restriction fragments of the B7 gene were assayed for their ability to enhance transcription of a bacterial chloramphenicol acetyltransferase gene from a simian virus 40 promoter in transiently transfected mouse LTA cells. Our results demonstrate that enhancer activity is located in introns 3 and 5 as well as 5' to the transcription initiation site. RNase protection experiments corroborate the results. Preliminary experiments indicate that B7 enhancers are active in various cell types. The role of these enhancers in B7 gene expression is not known at present. We speculate that the position of the enhancer elements may be related to the occurrence of Hpa II tiny fragment islands.

Animals↗
PubMed1989

Construction, stable transformation, and function of an amber suppressor tRNA gene in Drosophila melanogaster.

Drosophila melanogaster strains with a stably incorporated amber suppressor tRNA gene have been generated. A tRNATyr gene was site specifically mutated to produce an anticodon sequence that recognizes the amber codon and then introduced into Drosophila by using P-element-mediated transformation. Transformants from four integration events were recovered. Two integrations resulted in both male and female sterility, whereas the other two resulted in male sterility but female fertility. Strains derived from the two female-fertile integration events were shown to have a low level of amber-suppressing activity by their ability to suppress an amber mutation in a chloramphenicol acetyltransferase gene.

Animals↗