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Biomedical subjects

S Bhattacharya

Publications and source records attributed to S Bhattacharya.

At least 487 records · Page 27Linked to original sources
PubMed1987

Human interstitial retinol-binding protein (IRBP): cloning, partial sequence, and chromosomal localization.

A cloned 2184-bp cDNA coding for human interstitial retinol-binding protein (IRBP) has been isolated and sequenced. The probe hybridized to a 5.2-kb poly(A) RNA from human retinas. Nineteen tryptic peptides (363 amino acids) sequenced and purified from bovine IRBP could be aligned with 86-88% homology to the translated sequence. Two segments approximately 200 amino acids long were found to have a 41% residue identity, suggesting an internal duplication event. This cloned cDNA was used to probe DNA samples from a panel of 29 rodent-human somatic cell hybrids, mapping the structural gene for IRBP to chromosome 10. In situ hybridization suggested a regional localization near the centromere (p11.2----q11.2), although a secondary site of hybridization at q24----25 was also observed.

Amino Acid Sequence↗
PubMed1987

Differentiation of patients with rheumatic fever from those with inactive rheumatic heart disease using the artificial subcutaneous nodule test, myocardial reactive antibodies, serum immunoglobulin and serum complement levels.

Thirty patients with acute rheumatic fever, and 20 with inactive rheumatic heart disease were studied in order to determine parameters which differentiate the two groups. Subcutaneous nodules developed following the subcutaneous injection of autologous blood in 16 of 26 patients with rheumatic fever but in none of the 20 with inactive rheumatic heart disease (P = 0.00001). Myocardial reactive antibodies were found in 14 of 30 patients with rheumatic fever, and in 4 of 20 with inactive rheumatic heart disease (P = 0.0505). Significantly higher values of IgG (P less than 0.001), IgA (P less than 0.01), C3 (P less than 0.001) and C4 (P less than 0.001) were observed in rheumatic fever patients. There was no significant difference in IgM levels. A combination of three variables (artificial subcutaneous nodules, IgA, and C3) had a sensitivity of 87% and a specificity of 100% for rheumatic fever. A combination of two variables (artificial subcutaneous nodules and IgA) had a sensitivity of 84% and a specificity of 100% for rheumatic fever.

Adolescent↗
PubMed1987

Molecular genetic approaches to the analysis of human ophthalmic disease.

In this review of the recent literature, the contribution that the new techniques of molecular genetics has made in the analysis and diagnosis of human ophthalmic conditions is presented and discussed. Among the disorders reviewed are X-linked retinitis pigmentosa, Norrie's disease, gyrate atrophy and retinoblastoma, and there are also sections on crystallins and visual pigments.

Chromosome Mapping↗
PubMed1986

Quantification of LDL cholesteryl ester contribution to biliary steroids in the rat.

The proportion of LDL cholesteryl ester converted to biliary steroids was quantified in the rat. The pre-existing pool of bile was allowed to drain for 10-12 h through a bile duct cannula. A single intravenous pulse injection of LDL labelled with [3H]cholesterol linoleyl ester was made, followed by a constant infusion of the same material in order to maintain constant specific radioactivity in plasma. A new steady state was achieved within 6 h and bile samples were then collected hourly until 12 h. Although substantial amounts (53-61 micrograms/h) of cholesteryl ester were released into the liver during LDL catabolism, only a very small fraction (0.8-1.90 micrograms/h) was found in biliary steroids. The proportion of LDL cholesteryl esters contributing to biliary steroids was only 1-2%. These results perhaps explain why perturbations to accelerate bile acid excretion have no effect on plasma LDL cholesterol concentration in the rat.

Animals↗
PubMed1986

Regulation of low-density-lipoprotein metabolism in the rat.

The mechanism of regulation of plasma low-density-lipoprotein (LDL) metabolism in the rat was studied under a number of experimental conditions. LDL clearance and uptake in the liver was measured after intravenous pulse injection of [14C]sucrose-labelled LDL alone or in combination with reductively methylated [3H]sucrose-labelled LDL. Hyperthyroid rats showed a significant increase in fractional catabolic rate (FCR) and the proportion of LDL degraded in the liver, whereas the synthetic rate of LDL increased by 50%. Receptor-mediated clearance increased 2-fold. Hypothyroid rats showed a significant increase in LDL concentration. The FCR and proportion of LDL degraded in the liver were decreased significantly. Receptor-mediated clearance was also reduced. Cholesterol feeding increased chylomicron, very-low-density-and intermediate-density-lipoprotein cholesterol concentrations, but there was no change in the LDL concentration, FCR or the synthetic rate of LDL. Cholestyramine feeding did not induce changes in the kinetic parameters. These results indicate that, in the rat, the hepatic LDL-receptor pathway is under hormonal control, whereas cholesterol and cholestyramine feeding have no demonstrated effect on LDL metabolism.

Animals↗
PubMed1986

Binding of thyroid hormone to isolated ovarian nuclei from a freshwater perch, Anabas testudineus.

High affinity, low capacity 3,5,3'-triiodo-L-thyronine (T3) specific binding was detected in the pure nuclei preparation from ovarian tissue of freshwater perch by employing an in vitro thyroid hormone binding assay. Under standardized assay conditions of pH 7.0 at 30 degrees and 1 hr incubation time, the binding in the ovarian nuclei was saturable with a Kd 9.1 X 10(-9) M. For comparison, a Scatchard analysis of T3 binding to perch hepatic nuclei was done and a higher Kd value (16.89 X 10(-9) M) with twofold increase in maximum binding capacity (MBC 8.882 and 4.312 pmol/mg DNA in liver and ovary, respectively) was observed. Competitive inhibition studies showed ovarian T3 binding to be hormone specific with relative binding affinities comparable to T3 binding in other systems. T3 binding to the nuclear preparation from tail kidney and brain tissue of perch was considerably lower in comparison to liver and ovarian nuclei. Functional relevance of T3 binding to perch ovarian nuclei was tested by incubating ovarian tissue in vitro with T3. T3 significantly (P less than 0.001) increased protein synthesis in comparison to control.

Animals↗
PubMed1986

Antibody-based enzyme-linked immunosorbent assay for determination of immune complexes in clinical tuberculosis.

Immune complexes were isolated from sera of tuberculosis patients by precipitation with 2.5% polyethylene glycol. The precipitates were characterized by quantitative determination of different immunoglobulin classes by single radioimmunodiffusion, sodium dodecyl sulfate polyacrylamide gel electrophoresis for presence of serum components, Ouchterlony's double diffusion method for detection of complement components C3 and C4, and immuno-dot assay for detection of Mycobacterium tuberculosis antigens. The results showed that polyethylene glycol precipitates of patients' sera were indeed immune complexes, as they contained immunoglobulins, albumin, complement components, and mycobacterial antigens, whereas precipitates from control sera contained mainly albumin. The antibodies present in immune complexes were specific to M. tuberculosis antigen and showed no binding to Escherichia coli antigens. Immune complex levels, as determined by the ability to bind M. tuberculosis antigens in an enzyme-linked immunosorbent assay, were significantly higher in tuberculosis patients (n = 22) than in healthy control subjects (n = 18). Thus, immune complex level could be a useful parameter in the diagnosis of active tuberculosis.

Antibodies↗
PubMed1986

In-vitro binding of gonadotrophin to fish ovary.

Binding of piscine and mammalian gonadotrophin to plasma membranes from the ovaries of a fish, the murrel (Channa punctatus), clearly suggests that the fish ovary possesses distinct and specific binding sites for both piscine and mammalian gonadotrophins. Maximum specific binding of 125I-labelled human chorionic gonadotrophin (125I-hCG) and 125I-labelled silver carp gonadotrophin (125I-scG) was obtained at 30 degrees C and pH 7.5 during 2 h of incubation. In competitive binding studies, binding of radiolabelled scG was effectively inhibited by piscine gonadotrophins while LH and hCG had less effect and FSH showed no inhibition. By using plasma membrane preparations from kidney, skeletal muscle, brain and ovary it could be shown that specific binding of radiolabelled gonadotrophins was restricted to ovarian tissue. Binding characteristics of both 125I-scG and 125I-hCG to a preparation of murrel ovarian plasma membranes showed saturability with high affinity and low capacity. Scatchard plot analysis gave a higher dissociation constant for hCG (Kd = 235 pmol/l) than for scG (Kd = 127 pmol/l). Maximum binding capacity of scG was about twofold higher (6.27 fmol/mg protein) than that of hCG (3.76 fmol/mg protein). An increase in gonadotrophin binding resulted in a greater formation of pregnenolone from cholesterol, indicating functional relevance. At a concentration of 8 mmol/l, Ca2+ markedly inhibited the binding of gonadotrophin. The physiological importance of this inhibition is discussed.

Animals↗
PubMed1986

Biliary excretion of aluminum in aluminum osteodystrophy with liver disease.

Two patients with chronic liver disease developed elevated serum aluminum concentrations and biopsy-proven osteodystrophy. Neither patient had chronic renal failure but both had received aluminum-containing antacids for long periods. We measured biliary and urinary aluminum excretion during antacid loading in patients with normal liver function. Our studies show that biliary excretion is an important route of elimination of orally absorbed aluminum, and we suggest that long-term antacid therapy in patients with severe liver disease be monitored with periodic serum and urinary aluminum determinations to avoid aluminum osteodystrophy.

Adult↗