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Biomedical subjects

S Banerjee

Publications and source records attributed to S Banerjee.

At least 505 records · Page 28Linked to original sources
PubMed1989

Phosphoinositides from human foetal brain during development.

An attempt has been made in the present study to look for the activity of the enzymes which catalyse the breakdown of phosphorylated metabolites both in acidic and alkaline pH from human foetal brain, in different gestational ages during development in 18 foetal samples. It was revealed that phosphatases were distributed throughout the brain and were operative from the onset of development. There was a tendency of increment of specific activity of enzymes with respect to the advancement of gestational period. This observation should be accounted as a prerequisite criteria for understanding phosphate meatabolism in human foetal organs primarily associated with glycolytic and gluconeogenic pathways.

Brain↗
PubMed1989

Study of foetomaternal haemorrhage in relation to mode of delivery.

A study on 100 pregnant women regarding foetomaternal haemorrhage (FMH) in relation to mode of delivery with Kleihauer acid-elution technique revealed that FMH was affected by mode of delivery. Incidence of FMH was nil in normal spontaneous delivery without syntocinon drip but the incidence of FMH in normal delivery preceded by syntocinon drip was 19.05%, in forceps delivery 40%, in lower uterine caesarean section 50% and in normal delivery followed by manual removal of placenta 100%. The incidence of FMH was more in postpartum period (16%) than that in antenatal period (8%).

Delivery, Obstetric↗
PubMed1989

Genetic heterogeneity and population structure in eastern India: red cell enzyme variability in ten Assamese populations.

This paper is a part of the genetic study of the people of Assam (eastern India), initiated by the Anthropometry and Human Genetics Unit, Indian Statistical Institute, Calcutta, India, and the Dept. of Human Biology/Physical Anthropology, University of Bremen, W. Germany. The results of 1. allele distribution of five red cell enzyme polymorphisms in ten Assamese populations, 2. heterogeneity of allele frequencies and extent of gene differentiation among these populations, and 3. standard genetic distances are presented here. A total of 1024 blood samples was screened for aP, E D, AK, ADA and LDH enzyme systems for Brahmins, Kalitas, Kaibartas, Rajbanshis, Muslims, Ahoms, Chutiyas, Kacharis, Karbis (Mikirs) and Sonowals, of which the latter three are tribes. The gene diversity (FST) is smallest (0.0035) for pa and highest (0.1604) for HbE. The total FST value (0.0399 +/- 0.0141) appears to be statistically significant. From distance analysis two major clusters with sub-clusters in each are visible, which are in conformity with the ethnohistory of these populations.

Asian People↗
PubMed1989

Influence of hyperthermia on gamma-ray-induced mutation in V79 cells.

Asynchronously growing V79 cells were assayed for mutation induction following exposure to hyperthermia either immediately before or after being irradiated with 60Co gamma rays. Hyperthermia exposures consisted of either 43.5 degrees C for 30 min or 45 degrees C for 10 min. Each of these heat treatments resulted in a survival level of 42%. For all sequences of combined treatment with hyperthermia and radiation, cell killing by gamma rays was enhanced. Mutation induction by gamma rays was enhanced when heat preceded gamma irradiation, but no increase was observed when heat was given after gamma exposures. Treatment at 45 degrees C for 10 min gave a higher yield in mutants at all gamma doses studied compared to treatment at 43.5 degrees C for 30 min. When heat-treated cells were incubated for different periods before being exposed to gamma rays, thermal enhancement of radiation killing was lost after 24 h. In contrast, only 5-6 h incubation was needed for loss of mutation induction enhancement.

Animals↗
PubMed1989

Histochemical studies on the distribution of certain dehydrogenases in squamous cell carcinoma of cheek.

Histochemical distribution of lactate, isocitrate and succinate dehydrogenases in normal oral epithelium and in well differentiated squamous cell carcinoma of cheek region was studied. Lactate dehydrogenase, isocitrate dehydrogenase, and succinate dehydrogenase activity was found to be more in the malignant cells. Succinate and lactate dehydrogenase presented a conspicuous pattern in which the cells located at the periphery of the malignant sheets in well differentiated squamous cell carcinoma showed moderate to intense activity as compared to cells in the central portion. The results are discussed and it is suggested that the enhanced glycolysis and subdued function of the tricarboxylic acid cycle is not a universal criterion during malignancy as reported in the previous investigations.

Aged↗
PubMed1989

Sites, mechanisms, and structural characteristics of the brain's nicotine receptor.

Studies are described dealing with the molecular features of nicotine, the receptor binding and psychotropic properties of nicotine agonists and antagonists, and the neuroanatomical locus of action of nicotine associated with its psychotropic action. Bridged analogues of nicotine have been developed to define the optimal conformation of the molecule for maximal receptor affinity and psychotropic action in rats. With another series of analogues, it was demonstrated that contraction of the pyrrolidine ring to a 4-member azetidine enhances potency while expansion diminishes it. A major site for nicotine's central action is the vestibular cerebellum as demonstrated by kainic acid lesioning studies and direct administration of nicotine into this region. Included among the antagonists to nicotine was alpha-lobeline, which appeared to be a mixed agonist-antagonist.

Animals↗
PubMed1988

Structure, expression, and evolution of a gene encoding the precursor of nisin, a small protein antibiotic.

We have cloned and sequenced a gene (spaN) from Streptococcus lactis ATCC 11454 which encodes the peptide precursor of the small protein antibiotic nisin. The encoded precursor is 57 amino acids long, with a 23-residue leader region and a 34-residue structural region. The structural region contains serines, threonines, and cysteines at exactly the positions required to give mature nisin by a series of post-translational modifications involving dehydration of serines and threonines to dehydro forms, and cross-linking with cysteine residues. S1 mapping revealed a 267-nucleotide transcript of the nisin gene that is expressed during vegetative growth and stationary phase. It has a half-life of 7-10 min. The absence of an identifiable promoter or rho-independent terminator and the detection of two different 5'-ends of the transcript suggested it is a processing product from a larger RNA. This may represent a polycistronic mRNA which may also encode proteins involved in processing the nisin precursor peptide. Open reading frames were found in regions flanking the nisin gene. The one downstream had a ribosome binding site and appeared to be transcribed by read-through from the nisin gene. The one upstream had significant homology to a putative transposase from the Escherichia coli IS2 insertion element. Comparison of gene sequence homologies between nisin and the other lanthionine antibiotics, subtilin and epidermin, indicated that they all evolved from a common ancestor. Corresponding leader peptide sequences showed mediocre amino acid homology, but nearly perfect hydropathic homologies, suggesting a common function. It is proposed that this function includes recognition signals or other information required for post-translational processing.

Amino Acid Sequence↗
PubMed1988

Oxidative side-chain and ring fission of pregnanes by Arthrobacter simplex.

Metabolic processes involving side-chain and ring cleavage of progesterone, 17-hydroxyprogesterone, 11-deoxycortisol and 16-dehydropregnenolone by Arthrobacter simplex were studied. The formation of the metabolites from progesterone indicates a pathway somewhat different from normal in the enzymic reaction sequence, and the 17-hydroxyprogesterone metabolites reveal a non-enzymic rearrangement step. The presence of a hydroxy group at C-21, as in 11-deoxycortisol, induces reduction of the C-20 carbonyl group. The microbial preparation of a novel androstane analogue, 17 beta-hydroxy-16 alpha-methoxyandrosta-1,4-dien-3-one, by incubation of 16-dehydropregnenolone with the bacterial strain was achieved. The formation of this metabolite is a multistep process involving a novel microbial generation of a methoxy group from a double-bond transformation in a steroid skeleton.

17-alpha-Hydroxyprogesterone↗
PubMed1988

Immunosuppression of collagen-induced arthritis in mice with an anti-IL-2 receptor antibody.

The use of an anti-IL-2R antibody, 7D4, was investigated in vivo in the suppression of collagen-induced arthritis in mice. 7D4 was shown to reduce the incidence of arthritis in a group of mice immunized with type II collagen as compared with a group similarly immunized with collagen and treated with a control isotype matched anti-Forsmann antibody. 7D4 was also shown to reduce the severity of arthritis in the treated mice as compared to the mice in the group treated with the control antibody. Anti-IL-2R antibodies may be useful in the treatment of autoimmune diseases by selectively suppressing activated T cells.

Animals↗
PubMed1988

Structure and expression of a gene encoding the precursor of subtilin, a small protein antibiotic.

A gene has been cloned from Bacillus subtilis ATCC 6633 that encodes a 56-residue peptide precursor for the 32-residue peptide antibiotic, subtilin. The precursor contains serines, threonines, and cysteines at positions that permit them to undergo a series of dehydration and cross-linking steps to give the mature antibiotic peptide which contains the unusual amino acids lanthionine, beta-methyllanthionine, D-alanine, dehydroalanine, and dehydrobutyrine. The precursor peptide contains a leader region that has an unusual hydropathic character for an exported protein. The subtilin gene is expressed from a monocistronic transcriptional unit as identified by S1 mapping of the gene transcript. The (-35) region of the promoter is not typical of Bacillus subtilis vegetatively-expressed genes. The subtilin transcript was present in very low amounts during exponential growth, but in large amounts during stationary phase; at which time mature subtilin peptide and antibiotic activity were also observed. The subtilin transcript contains a cleavage-sensitive region that overlaps the ribosome binding site. The primary transcript has an unusually long half-life of about 45 min. These observations confirm that subtilin is derived from a small protein that is synthesized on ribosomes.

Amino Acid Sequence↗
PubMed1988

Possible role of V beta T cell receptor genes in susceptibility to collagen-induced arthritis in mice.

Arthritis was induced by immunization of type II collagen in adjuvant in mice from H-2q-bearing crosses between SWR (H-2q/q) and B10 (H-2b/b mice), two strains known to be resistant to collagen-induced arthritis (CIA). The resistance of B10 is known to be due to its MHC haplotype, but it was postulated that the resistance of SWR mice which expresses the susceptible MHC haplotype could be due to the deletion of close to 50% of the V beta genes of the T cell receptor (TCR) in them. 17% of the F1 hybrids, 33% of the SWR backcrosses, 68% of the B10 backcrosses, and 52% of the F2 hybrids developed arthritis on follow-up to 5 mo after primary immunization with collagen. There was no significant difference in anti-type II collagen antibody titers between the arthritic and nonarthritic mice in each of these crosses. The segregation of the TCR genes with arthritis was determined in the F2 population by typing with F23.1 mAb that reacts with T cells using V beta 8 subfamily genes in their TCRs. SWR mice are F23.1- as V beta 8 genes are deleted in them. All six of arthritic mice homozygous for H-2q, and thus with an H-2 haplotype similar to SWR mice, expressed the F23.1 marker. These studies indicate that for complete susceptibility to collagen-induced arthritis, not only is a susceptible MHC haplotype (H-2q) important, but possibly also the presence of a subset of T cells using certain specific V beta genes in their TCRs. Other background genes may, however, modulate the severity of arthritis.

Animals↗
PubMed1988

Water solubility: a critique of the solvatochromic approach.

The reasoning and some of the assumptions behind the solvatochromic approach to water solubility are evaluated, particularly in relation to its claims. It is shown that the contribution of the pi term is uncertain, and that it can be dropped from the correlation without substantially affecting the degree of fit. The solvatochromic method is compared with the long-standing relationship between solubility and the octanol-water partition coefficient, and it is demonstrated that the latter offers a far superior route to solubility estimation.

Chemistry, Pharmaceutical↗