Search PubMed⌕ Search

Biomedical subjects

A K Chatterjee

Publications and source records attributed to A K Chatterjee.

At least 73 records · Page 4Linked to original sources
PubMed1988

Effect of chloroquine on biosynthesis, release and degradation of insulin in isolated islets of rat pancreas.

Insulin has been reported to degrade inside the islets and islet lysosomal proteases have been thought to take part. As chloroquine is regarded as a potent lysosomotropic agent, an attempt has been made to see whether chloroquine has an influence on intrainsular degradation of insulin. After preculture of collagenase-isolated rat islets at 11 mM glucose together with [3H]leucine for 3 days for labelling newly synthesized insulin, islets were cultured for 1 day at 2.2 or 22 mM glucose with or without 0.02 mM chloroquine. Afterwards, radioactivity was measured in the proinsulin/insulin fraction. For control, the influence of chloroquine during 3-h incubation of both freshly isolated and precultured islets was also studied. During the 1-day culture at 2.2 mM glucose, prelabelled insulin was degraded significantly and addition of chloroquine did not alter the amount of insulin degraded. At 22 mM glucose, no significant amount of insulin had been degraded. During the 3-h incubation of freshly isolated as well as precultured islets, chloroquine was found to inhibit significantly glucose-induced biosynthesis of insulin. Glucose-induced release of insulin, however, was not influenced by chloroquine. It is concluded that chloroquine does not influence glucose-induced release or intra-insular degradation of insulin, but it interferes with the biosynthesis of insulin.

Animals↗
PubMed1988

Age-related susceptibility to the insulin-depleting action of 4-diphenylmethylpiperidine in young rats.

Studies were undertaken to investigate age-related changes in the ability of 4-diphenylmethylpiperidine (4-DPMP) to reduce levels of pancreatic insulin in young rats. Oral doses of 4-DPMP (5.0 or 10.0 mg/kg) were given once daily for two days to 9-, 15- and 21-day-old rats. Twenty-four hours after the last dose, pancreatic insulin content, non-fasting serum glucose, and the amount of unchanged 4-DPMP present in the whole body were estimated. 4-DPMP treatment produced a decline in pancreatic insulin and the extent of this action was greater in younger animals. The observed changes in pancreatic insulin were not reflected in altered serum glucose levels, showing this parameter is a relatively poor indicator of pancreatic insulin loss. Younger animals had a larger fraction of the total dose of 4-DPMP in the body at the end of the experimental period when compared to the fraction retained by older rats. The age-related susceptibility of young rats to the diabetogenic action of 4-DPMP may be related to the differences in the rate of elimination of the chemical at different ages.

Aging↗
PubMed1988

Shoe dermatitis in India.

105 patients with foot dermatitis, seen over a period of 18 months, were patch tested with various shoe allergens. 47 showed a positive reaction to 1 or more allergens. The majority of the cases (37-47) were chrome-positive. Positivity to plastic material was observed in 8, whereas rubber and rubber chemicals accounted for 5 cases. Of special interest were positive reactions to 1,3-diphenylguanidine in 3 and N-cyclohexyl-2-benzothiazolesulfenamide in 2 cases.

Allergens↗
PubMed1988

Genetic organization and regulation of proteins associated with production of syringotoxin by Pseudomonas syringae pv. syringae.

Many strains of Pseudomonas syringae pv. syringae produce one of two low-molecular-weight, peptide-containing phytotoxins, either syringomycin (SR) or syringotoxin (ST). An analysis of Tn5-induced ST-mutants revealed alterations in the presence of two large proteins (ca. 470 and 435 kilodaltons). Apparent truncated forms of the 470 (ST1)- or 435 (ST2)-kilodalton proteins were observed in some mutants. Mapping of the Tn5 insertions and size determinations of truncated proteins suggested that both ST1 and ST2 are in the same transcriptional unit, with ST1 being directly upstream of ST2. When an ST-producing strain of P. syringae pv. syringae was grown under toxin-inducing conditions, ST1 and ST2 were first detected at the end of the exponential phase of growth, which was when the first accumulation of ST was observed. High iron levels were essential for efficient ST production. At concentrations of FeCl3 of between 0.2 and 5 microM, the amount of toxin accumulated was almost directly proportional to the iron concentrations. The amount of ST1 and ST2 present showed a corresponding increase in response to iron concentrations. Our genetic and physiological data implicate ST1 and ST2 in the biosynthesis of syringotoxin.

Bacterial Toxins↗
PubMed1988

Stimulatory effect of insulin-like growth factor-I on [3H]thymidine incorporation, DNA content and insulin biosynthesis and secretion of isolated pancreatic rat islets.

The influence of insulin-like growth factor-I (IGF-I) on both the growth and function of isolated pancreatic rat islets was studied. As a measure of islet cell replication, [3H]thymidine incorporation and DNA content was estimated at the same time as parameters for (pro)insulin biosynthesis and secretion as a measure of the functional capacity of B cells. Incorporation of [3H]thymidine was measured after tissue solubilization; DNA was determined fluorometrically. (Pro-)insulin biosynthesis was determined by incorporation of [3H]leucine after immunoprecipitation and binding to protein A-Sepharose. There was a significant increase in both [3H]thymidine incorporation and DNA content after the culture of islets with IGF-I. IGF-I resulted also in an increase in insulin biosynthesis and secretion from isolated pancreatic islets. These results demonstrate a role of IGF-I in regulating the growth and function of pancreatic islets.

Animals↗
PubMed1988

Pain quantum and wound healing: a comparison of interrupted inversion PDS and standard nylon sutures in abdominal skin closure.

Patients' postoperative pain experience during 5 days after hernia repairs or upper abdominal procedures was compared when skin closure was achieved by either full thickness interrupted sutures or subcuticular interrupted inversion sutures. Quantitative pain assessments were made using linear analogue charts and standardised analgesic requirements. Clinical advantage for the subcuticular technique was confirmed for the hernia group and possible advantage in the upper abdominal closure, suggested by lesser analgesic requirement. Statistical analysis has lent support to the hernia group findings but is less clear in the upper abdominal group. A comparison of wound healing, sepsis and cosmetic outcome showed no apparent advantage to either method. Economies and patient preference favoured the subcuticular method.

Abdominal Muscles↗
PubMed1987

Genetic analysis of the pelA-pelE cluster encoding the acidic and basic pectate lyases in Erwinia chrysanthemi EC16.

In Erwinia chrysanthemi (EC16) the clustered pelA and pelE genes encode an acidic (pI 4.2) and a basic (pI 10.0) pectate lyase (Pel), respectively. The pelA gene has been isolated on a 1.2 kb restriction fragment and the direction of transcription determined. DNA hybridization analysis showed that the pelE sequence shares DNA homology with pelA but not with pelB or pelC, two genes encoding other Pel species in EC16. Since Pel A and Pel E enzymes showed little similarity in terms of catalytic properties, it is proposed that pelA and pelE are duplicates which have highly diverged.

Blotting, Southern↗
PubMed1987

Regulation of biosynthesis, release and degradation of insulin in cultured rat islets.

In order to study the long-term influence of glucose on islet cell functions, biosynthesis of (pro)insulin (3H-leucine incorporation during 3h-incubation both at 50 and 300 mg/dl of glucose), release of insulin and somatostatin and degradation of intra-insular insulin were measured in isolated rat islets, cultured for 3 days at 50, 150 and 300 mg/dl glucose. After culture at 50 mg/dl of glucose, (pro) insulin biosynthesis was very low during 3 h incubation in presence of either 50 or 300 mg/dl glucose; whereas, after culture at 300 mg/dl glucose, a sustained high rate of biosynthesis was observed. This priming-effect concerning hormone release during incubation period, in relation to the previous glucose concentration of culture medium was better proportional for D-cells than for the B-cells. During the 3 days of culture, the percentual differences in hormone release at 50, 150 and 300 mg/dl of glucose were, altogether, also higher for somatostatin than for insulin. Insulin degradation was strongly enhanced during culture at 50 mg/dl glucose (total insulin before culture: 526 +/- 57 microU/islet; after culture at 50, 150 and 300 mg/dl glucose (in islets plus media): 253 +/- 25, 975 +/- 90 and 1030 +/- 96 microU/islet, respectively). The glucose-priming of islet cells differed for the various cell functions. At low glucose concentration the pre-synthesized insulin (which was not needed then physiologically) was again degraded within the islet cells; at higher concentrations of glucose, increased stimulation of the B-cells seemed to be modified by the--paracrine--action of somatostatin.

Animals↗
PubMed1987

Impact of amino acid imbalance on brain amines.

The brain levels of serotonin (5-HT), norepinephrine (NE) and dopamine (DM) were studied in amino acid imbalance, induced in rats by feeding them an 8% casein diet supplemented with 0.3% L-threonine. In addition, tryptophan hydroxylase (TPH) and monoamine oxidase (MAO) activities in the brain were measured. The studies revealed that induction of amino acid imbalance decreased the brain levels of 5-HT and NE, and increased the DM level significantly. These changes in the amine levels were found to be accompanied by increases in the activities of TPH and MAO of brain. It has been suggested that the enhanced activity of brain TPH in threonine imbalance was probably brought about by a conformational change of the enzyme protein and might be an adaptive response to the low level of 5-HT in the brain due to increased MAO activity. The increased brain DM level in threonine imbalance could be ascribed to enhanced entry of tyrosine in the catecholamine anabolic pathway, while the diminished brain NE level under the same condition might result from its increased degradation or diminished conversion of DM to NE due to supposedly inhibition of DM-beta-hydroxylase.

Amino Acids↗
PubMed1985

Effect of epinephrine and norepinephrine on immuno-reactive insulin secretion from isolated islets of Langerhans.

Earlier studies have demonstrated the inhibitory nature of epinephrine and norepinephrine on pancreatic insulin release. The present study reports their effect on beta-cell IRI release in an isolated islet system. Results show that epinephrine and norepinephrine inhibit islet-IRI release at the 100-10 microM level. The alpha adrenergic blocker phentolamine (100 microM) but not the beta adrenergic blocker propranolol (100 microM) can reverse this catecholamine induced inhibition of islet-IRI release. This clearly suggests that epinephrine and norepinephrine inhibit insulin release via alpha-adrenergic pathway.

Animals↗
PubMed1985

Fracture dynamics of fusion of two anti-plane cracks.

The problem of the fracture dynamics of two two-dimensional coplanar anti-plane shear cracks is considered. Both cracks extend under a critical stress-intensity fracture criterion. The two cracks are initiated at different locations and times. A solution developed by Kostrov [Kostrov, B. V. (1966) J. Appl. Math. Mech. 30, 1241-1248] for isolated cracks is used to determine the tearing loci of the cracks up to the time at which the individual cracks begin to interact. In the interaction interval prior to the fusion of the two cracks, both the stresses and the fracture tip loci are determined sequentially by applying the solution to Abel's equation twice iteratively. This method can be used to solve problems of the fusion of any number of coplanar cracks.

Journal Article↗
PubMed1985

Cloning and expression in Escherichia coli of pectinase genes of Erwinia carotovora subsp. carotovora.

Genes coding for an endo-pectate lyase, an exo-pectate lyase, and an endopolygalacturonase of Erwinia carotovora subsp. carotovora Ecc71 were cloned in Escherichia coli HB101, using the cosmid pHC79. The products of the cloned pectinase genes paralleled their counterparts in strain Ecc71 in isoelectric mobility, mode of substrate degradation, and ability to macerate potato tuber tissue.

Cloning, Molecular↗
PubMed1985

pULB113, an RP4::mini-Mu plasmid, mediates chromosomal mobilization and R-prime formation in Erwinia amylovora, Erwinia chrysanthemi, and subspecies of Erwinia carotovora.

The RP4::mini-Mu plasmid pULB113, transferred from Escherichia coli strain MXR, was stable and transfer proficient in Erwinia amylovora strain EA303, E. carotovora subsp. atroseptica strain ECA12, E. carotovora subsp. carotovora strain ECC193, and E. chrysanthemi strain EC183. The plasmid mobilized an array of Erwinia sp. chromosomal markers (E. amylovora: his+,ilv+,rbs+,ser+,thr+;E. chrysanthemi:arg+,his+,ilv+,leu+; E. carotovora subsp. atroseptica: arg+,gua+,leu+,lys+,pur+,trp+; E. carotovora subsp. carotovora: arg+,gua+,leu+,lys+,out+[export of enzymes],pur+,trp+), suggesting random interactions of the plasmid with the chromosomes. In E. carotovora subsp. carotovora, pULB113-mediated two-factor crosses revealed linkage between three auxotrophic markers and the out loci. The export of pectate lyase, polygalacturonase, and cellulase and the maceration of potato tuber tissue occurred with Out+, but not Out-, strains of E. carotovora subsp. carotovora, indicating the importance of enzyme export in plant tissue maceration. Erwinia sp. donors harboring pULB113 complemented mutations in various biosynthetic and catabolic genes (arg, gal, his, leu, met, pro, pur, thy) in Escherichia coli recA strains. Escherichia coli transconjugants harbored pULB113 primes as indicated by the cotransfer of Erwinia genes and pULB113 markers and a change in plasmid mass. Moreover, the PstI and SmaI cleavage patterns of selected pULB113 primes were different from those of pULB113. pULB113 primes carried DNA insertions ranging from 3 to about 160 kilobases. These findings indicate that pULB113 is useful for in vivo gene cloning and genetic analysis of various enterobacterial phytopathogens.

Chromosome Mapping↗
PubMed1985

Single-site chromosomal Tn5 insertions affect the export of pectolytic and cellulolytic enzymes in Erwinia chrysanthemi EC16.

Exponentially growing cells of Erwinia chrysanthemi EC16 usually export about 98% of their pectate lyase (PL) and protease, about 40% of their polygalacturonase (PG), and about 60% of their cellulase (endoglucanase or carboxymethyl cellulase; CL). By using the R plasmid, pJB4JI (pPH1JI::Mu::Tn5), three independent Tn5 insertion mutants were obtained that exported normal levels of protease but 10% or less of PL, PG, and CL. Physical analysis revealed that single copies of Tn5 had inserted into the E. chrysanthemi chromosome, producing a similar export-defective (Out-) phenotype. The synthesis of PL, PG, and CL was not affected by the Tn5 insertions. These enzymes were released from the mutants on spheroplast formation, indicating that they were located in the periplasmic space. Tn5 insertions caused the loss of a 35-kilodalton periplasmic protein, but did not alter the outer membrane protein composition. The findings are discussed with respect to the current knowledge on protein export in gram-negative bacteria.

Cellulase↗