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Biomedical subjects

D Gupta

Publications and source records attributed to D Gupta.

At least 37 records · Page 2Linked to original sources
PubMed1995

Spinal cord dynorphin precursor intermediates decline during late gestation.

This laboratory has previously reported that the maternal opioid analgesia associated with pregnancy and parturition is mediated, at least in part, by a maternal spinal cord dynorphin/kappa opioid system. This analgesia is accompanied by an increase in dynorphin peptides (1-17 and 1-8) in the lumbar spinal cord. Levels of trypsin-generated arginine6-leucine-enkephalin (Leu-Enk-Arg)-immunoreactive determinants were also determined and used to reflect the content of dynorphin precursor intermediates. In spinal tissue, the amount of dynorphin A (1-17) contained in the form of precursor is, at a minimum, 10-fold higher than the content of mature dynorphin A (1-17) or dynorphin (1-8). During gestational day 22, the content of dynorphin precursor is reduced significantly (approximately 50%). The decline in the magnitude of dynorphin precursor intermediates in the spinal cord of pregnant rats vastly exceeds the magnitude of increase in the content of dynorphin peptides (1-17 and 1-8). This difference can best be explained by postulating a corresponding increase in the rate of release of spinal cord dynorphin (1-17). It is suggested that enhanced processing of dynorphin precursor intermediates represents the initial biochemical level of adaptation of spinal dynorphin neurons to increased demands of pregnancy.

Analgesia↗
PubMed1995

Anaesthetic management of acute puerperal uterine inversion.

We identified 18 cases of acute puerperal uterine inversion after vaginal delivery out of 65,581 deliveries in two university-affiliated hospitals (an incidence of 1:3643). In all cases manual repositioning of the uterus without tocolysis was attempted. In four cases this was successful. Of the 14 patients requiring tocolysis, a single dose of terbutaline 0.25 mg i.v. was tried in eight and was successful in five cases (success rate of 63%), while in three patients general anaesthesia was required. In six other patients, general anaesthesia was chosen as the initial management. There was no associated maternal mortality or morbidity with the exception of one case of acute postpartum endometritis. We suggest that when tocolysis is required, terbutaline should be used first because of its rapid onset of action, short duration, simplicity, availability in the labour suite and familiarity to the obstetrician, and general anaesthesia, with its inherent dangers, if possible, should be avoided.

Acute Disease↗
PubMed1995

Analysis of donor-deferral pattern in a voluntary blood donor population.

A retrospective analysis of records of the deferred donors from 1 October 1992 to 31 December 1993 was performed. Of 14,269 prospective blood donors (13,030 males and 1,239 females), 2,431 (16.4%) donors were disqualified for various reasons: 8.1% of the donors were deferred for non-pathological causes while 91.9% were deferred for medical reasons. The most common cause for non-pathological deferral was volunteers attending below the minimum acceptable age (5.2%). Abnormal findings on physical examination accounted for 57.2% of the deferrals in which low body weight was the most common finding (32.3%) followed by low Hb (18.6%). A past history of jaundice was the leading cause for deferral on medical interview. Numerous prospective donors are currently being deferred based on empirically derived criteria. By developing strategies to identify and rationalize donor selection criteria, the blood transfusion services should be able to decrease unnecessary deferrals.

Adolescent↗
PubMed1995

Magnetic resonance appearance of tuberculosis of the knee joint with ruptured Baker's cyst.

After the spine, the knee joint is the most commonly affected joint in skeletal tuberculosis. Baker's cyst is a rather rare complication of knee joint tuberculosis. The plain radiographic appearance of the tuberculous knee joint has been amply described. We present the magnetic resonance appearance of a tuberculous knee joint associated with a ruptured popliteal cyst.

Biopsy, Needle↗
PubMed1995

Melatonin affects proopiomelanocortin gene expression in the immune organs of the rat.

The induction of opioid peptides derived from cells of the immune system is postulated to be the main mechanism involved in the immunomodulatory role of melatonin. In this study, it has been demonstrated for the first time that melatonin can act on the level of proopiomelanocortin (POMC) gene expression. The effect of the pineal hormone, administered in late-afternoon subcutaneous injections, was studied in the immune organs of adult male Wistar rats by means of a highly sensitive reverse transcription polymerase chain reaction method (RT-PCR), followed by polyacrylamide gel electrophoresis and densitometric analysis of the bands. It was demonstrated that melatonin stimulates the expression of the 3rd exon of the POMC gene in the lymph nodes and in bone marrow. No significant effects of the pineal hormone were observed in the spleen and thymus. The study establishes that the formation of short POMC transcripts in the bone marrow and lymph nodes may be upregulated by melatonin. Moreover, the pineal hormone exerts its effect without antigenic stimulation.

Animals↗
PubMed1995

Effect of mild malnutrition on disaccharidase activity and glucose uptake in intestinal brush border vesicles of growing monkeys.

BACKGROUND: The effect of severe malnutrition has been reported by some workers, but there is a paucity of information on milder forms even though 85% of pre-school children show evidence of mild to moderate malnutrition in India. METHODS: Mild to moderate protein energy malnutrition was induced in 12 monkeys, and 12 were kept as controls. After a 30-40% reduction in body weight as compared with their controls, the animals were killed, and brush border membrane vesicles were prepared from three small parts of the small intestine. Purified vesicles were used for the assay of lactase, sucrase, maltase and glucose uptake in vitro. RESULTS: The activity of lactase, sucrase, and maltase, and uptake of (U-14C)-D-glucose was decreased in all three parts of small intestine, and the lactose tolerance test result was also abnormal in the protein energy-malnourished group. On nutritional rehabilitation, the disaccharidase activities recovered completely. CONCLUSION: This study indicates that even mild to moderate malnutrition decreases the digestion and absorption of carbohydrates throughout the small intestine, and it should not be ignored during the developing stage.

Animals↗
PubMed1995

Assessment of optimal dose of lactose for lactose hydrogen breath test in Indian adults.

To evaluate the possibility of using a 12.5 g or 25 g oral dose of lactose for hydrogen breath test for diagnosis of lactose intolerance instead of the usual 50 g dose. 35 patients with non-ulcer dyspepsia and an abnormal 50 g lactose breath hydrogen of more than 20 ppm over the base line were retested using 12.5 g and 25 g lactose. 32 (91.4%) and 15 (42.8%) of these 35 patients had an abnormal hydrogen breath test using 25 g (p = ns compared to 50 g dose) and 12.5 g (p < 0.001) lactose doses respectively. This study reveals that it may be possible to use a 25 g lactose dose instead of a 50 g dose for the lactose hydrogen breath test.

Breath Tests↗
PubMed1994

Observation of unique cross-linked lattices between multiantennary carbohydrates and soybean lectin. Presence of pseudo-2-fold axes of symmetry in complex type carbohydrates.

The tetrameric lectin from Glycine max (soybean) (SBA) has been shown to cross-link and precipitate with N-linked multiantennary complex type oligosaccharides containing nonreducing terminal Gal residues (Bhattacharyya, L., Haraldsson, M., & Brewer, C. F. (1988) Biochemistry 27, 1034-1041). In the present study, negative stain electron micrographs of the precipitates of SBA with a series of naturally occurring and synthetic multiantennary carbohydrates with terminal Gal or GalNAc residues show the presence of highly ordered cross-linked lattices for many of the complexes. The precipitates of SBA with a "bisected" and "nonbisected" N-linked biantennary complex type oligosaccharide containing Gal residues at the nonreducing termini show similar two-dimensional patterns. However, the pattern observed for the precipitates of a tetraantennary complex type oligosaccharide with SBA is distinct from those of the two biantennary carbohydrates. Furthermore, the precipitates formed between the lectin and a synthetic O-linked biantennary ("cluster") glycoside with terminal GalNAc residues show a pattern that is different from those above. Four biantennary pentasaccharide analogs of the blood group I antigen containing beta-LacNAc moieties at the 2,3-, 2,4-, 2,6-, and 3,6-positions of the core Gal also showed ordered patterns in their precipitates with SBA. X-ray crystallographic data and mixed quantitative precipitation profiles of binary mixtures of the four analogs demonstrate that each analog possesses a unique cross-linked lattice with the protein. A common structural feature of the naturally occurring and synthetic carbohydrates that show highly organized cross-linked lattices with SBA is the presence of a pseudo-2-fold axis of symmetry in each oligosaccharide relating the terminal binding epitopes on each arm. This suggests that the symmetry features of certain naturally occurring branch chain oligosaccharides facilitate formation of highly ordered, homogeneous cross-linked complexes with specific lectins.

Carbohydrate Conformation↗
PubMed1994

Homogeneous aggregation of the 14-kDa beta-galactoside specific vertebrate lectin complex with asialofetuin in mixed systems.

The galactose-specific 14-kDa family of animals lectins are an evolutionary conserved group of proteins that have been implicated in a wide variety of biological processes including cell proliferation, adhesion, and transformation. The present study demonstrates that the dimeric 14-kDa calf spleen lectin forms homogeneous aggregated cross-linked complexes with asialofetuin, a glycoprotein with multiple carbohydrate chains possessing terminal galactose residues, in the presence of other lectins with similar specificities and cross-linking activities. Several galactose-specific plant lectins also form homogeneous aggregated cross-linked complexes with ASF. These results demonstrate a new source of specificity for the 14-kDa family of vertebrate lectins, namely, the ability to selectively cross-link and aggregate glycoproteins in mixed systems. The results have important biological implications for the interactions of multivalent lectins and glycoconjugates, as well as the thermodynamic interactions of multivalent molecules in general.

Animals↗
PubMed1994

Observation of unique cross-linked lattices between multiantennary carbohydrates and soybean lectin. Presence of pseudo-2-fold axes of symmetry in complex type carbohydrates.

The tetrameric lectin from Glycine max (soybean) (SBA) has been shown to cross-link and precipitate with N-linked multiantennary complex type oligosaccharides containing nonreducing terminal Gal residues (Bhattacharyya, L., Haraldsson, M., & Brewer, C. F. (1988) Biochemistry 27, 1034-1041). In the present study, negative stain electron micrographs of the precipitates of SBA with a series of naturally occurring and synthetic multiantennary carbohydrates with terminal Gal or GalNAc residues show the presence of highly ordered cross-linked lattices for many of the complexes. The precipitates of SBA with a "bisected" and "nonbisected" N-linked biantennary complex type oligosaccharide containing Gal residues at the nonreducing termini show similar two-dimensional patterns. However, the pattern observed for the precipitates of a tetraantennary complex type oligosaccharide with SBA is distinct from those of the two biantennary carbohydrates. Furthermore, the precipitates formed between the lectin and a synthetic O-linked biantennary ("cluster") glycoside with terminal GalNAc residues show a pattern that is different from those above. Four biantennary pentasaccharide analogs of the blood group I antigen containing beta-LacNAc moieties at the 2.3-, 2.4-, 2.6-, and 3.6-positions of the core Gal also showed ordered patterns in their precipitates with SBA. X-ray crystallographic data and mixed quantitative precipitation profiles of binary mixtures of the four analogs demonstrate that each analog possesses a unique cross-linked lattice with the protein.(ABSTRACT TRUNCATED AT 250 WORDS)

Binding Sites↗
PubMed1994

Differences in the cross-linking activities of native and recombinant Erythrina corallodendron lectin with asialofetuin. Evidence for carbohydrate-carbohydrate interactions in lectin-glycoprotein complexes.

A previous study showed that several multivalent galactose-specific lectins including the 14-kDa lectin from calf spleen and the lectins from Erythrina indica, Erythrina cristagalli, and soybean agglutinin formed specific cross-linked complexes with the glycoprotein asialofetuin (ASF) [Mandal, D. K., & Brewer, C. F. (1992) Biochemistry 31, 8465-8472]. In the present study, we have used quantitative precipitation analysis to compare the cross-linking activities of the Gal/GalNAc-specific lectin from Erythrina corallodendron (ECorL) and the recombinant protein (rECorL) which lacks the covalently linked heptasaccharide chains of the native lectin, with ASF. At low concentrations of ASF relative to the lectin, native dimeric ECorL binds to each of the three terminal Gal residues of the three N-linked triantennary chains of ASF and precipitates as a cross-linked complex at a ratio of 1:9 ASF/lectin (monomer). With increasing concentrations of ASF, the 1:9 complex changes to a 1:3 ASF/lectin complex, and at higher ASF concentrations, a 1:1 cross-linked complex forms. However, rECorL, which possesses the same specificity and binding affinity as the native lectin, forms only the 1:9 and 1:3 ASF/lectin complexes. Other Erythrina lectins examined, all of which have covalently attached carbohydrate and are structurally similar to ECorL, show the same cross-linking behavior as native ECorL. On the other hand, the dimeric 14-kDa calf spleen lectin which lacks covalently attached carbohydrate forms only 1:9 and 1:3 cross-linked complexes with ASF [Mandal, D. K., & Brewer, C. F. (1992) Biochemistry 31, 8465-8472].(ABSTRACT TRUNCATED AT 250 WORDS)

Asialoglycoproteins↗
PubMed1994

Heparin, sulfated heparinoids, and lipoteichoic acids bind to the 70-kDa peptidoglycan/lipopolysaccharide receptor protein on lymphocytes.

The same 70-kDa protein, present on the surface of mouse lymphocytes, served as the predominant binding site for heparin, heparinoids, and bacterial lipoteichoic acids, as well as peptidoglycan and lipopolysaccharides. This conclusion was supported by the following results: (a) all of these compounds photoaffinity cross-linked to one major 70-kDa 6.5-7.0 pI protein that co-migrated on two-dimensional polyacrylamide gel electrophoresis; (b) peptide maps of the 70-kDa proteins digested with chymotrypsin, subtilisin, protease V, or papain yielded the same peptides for heparin-, lipoteichoic acid-, peptidoglycan-, and lipopolysaccharide-binding proteins; (c) cross-linking of peptidoglycan, lipopolysaccharide, lipoteichoic acid, and heparin was competitively inhibited by the same compounds with the same order of potency, i.e. carboxyl-reduced sulfated heparin > peptidoglycan > pentosan polysulfate > heparin > chitin > dextran sulfate > trestatin sulfate > polyanetholesulfonate > fucoidan > beta-cyclodextrin tetradecasulfate > heparan sulfate > carrageenan lambda > lipoteichoic acids > Re-lipopolysaccharide > lipopolysaccharide > lipid A > polygalacturonic acid; and (d) cross-linking of each of these ligands was not inhibited by carboxyl-reduced heparin, dextran, beta-cyclodextrin, trestatin, carrageenan kappa, chondroitin 4-sulfate, chondroitin 6-sulfate, beta-D-glucan, carboxy-methylcellulose, levan, alpha-D-mannan, and glycogen. The minimum size of the molecule that bound was 7-9 glycan residues, whereas, di- and trisaccharides did not bind. There was a logarithmic linear relationship between the strength of the binding and the length of the polymer (up to > 1500 glycan residues), which indicates an avidity effect of the cooperative binding of one polymeric molecule to several receptor molecules on the cell surface. The 70-kDa receptor, therefore, has a broad, but limited specificity of binding for non-charged (peptidoglycan and chitin), highly negatively charged (heparin and heparinoids), and weakly negatively charged (lipoteichoic acids, lipopolysaccharides, and lipid A) ligands.

Acute-Phase Proteins↗
PubMed1994

Neuroendocrine alterations in uveitis patients.

Experimental models of autoimmune uveitis are consistently associated with pinealitis. To investigate the interaction between the neuroendocrine and immune systems in humans with uveitis, we measured serum levels of the predominant pineal hormone melatonin (MEL), prolactin (PRL) and interleukin-2 (IL-2). A total of 100 patients with different forms of uveitis and 30 age-matched, healthy blood donors were evaluated retrospectively. The day-time MEL was reduced significantly (P < or = 0.01) in patients with iritis and iridocyclitis, and highly significantly (P < or = 0.001) in patients with intermediate uveitis, chorioretinitis and panuveitis. In 38% of patients day-time MEL levels in plasma were below the limit of detection. PRL was significantly reduced (P < 0.01) in patients with intermediate uveitis. IL-2 was reduced to about 50% of control values in all groups of patients. The results suggest a possible neuroendocrine-immune interaction in uveitis patients.

Adolescent↗
PubMed1994

Synthesis of neoglycopeptides and analyses of their biodistribution in vivo to identify tissue specific uptake and novel putative membrane lectins.

Complex type N-linked oligosaccharides derived from fetuin, fibrinogen and thyroglobulin were coupled to acetyltyrosine affording a series of neoglycopeptides with retention of terminal structures and the beta-anomeric configuration of their reducing end N-acetylglycosamine residue. The neoglycopeptides thus synthesized could be labelled to high specific activities with 125I in the aromatic side chain of tyrosine. Analysis of the fate of these neoglycopeptides in conjunction with inhibition with asialofetuin and oligosaccharides of defined structure in mice in vivo revealed the uptake of galactosylated biantennary compound by kidneys, in addition to the known itinerary of triantennary galactosylated complex oligosaccharide from fetuin to liver and the galactosylated biantennary chain with fucosylation in the core to bone marrows. On the other hand, the agalacto, aglucosamino biantennary chains with and without fucosylation in the core region are taken up by submaxillary glands while the conserved trimannosyl core with fucose is primarily concentrated in stomach tissue. These studies thus define new routes for the uptake of complex N-linked glycans and also subserve to identify lectins presumably involved in their recognition.

Animals↗
PubMed1994

Pathogenesis of the prune belly syndrome.

The triad of abnormalities of the prune belly syndrome may arise simply from the effects of early urethral obstruction or alternatively from a basic defect of the mesoderm from which the triad of abnormalities develops. The urethra and genital tract of 21 prune belly syndrome specimens and 23 specimens of Young's posterior urethral valves types 1 and 3 were compared in a study for differences in the pathological anatomy that may elucidate the controversy. The specimens were dissected and investigated radiographically and histologically. The seminal ducts and vesicles, and prostatic glands were abnormal in the prune belly syndrome specimens and normally developed in the posterior urethral valve specimens. We contest that this major difference stems from a primary defect of the intermediate and lateral plate mesoderm in the prune belly syndrome which would affect the embryogenesis not only of the mesonephric and paramesonephric ducts but also of the musculature of the abdominal wall and urinary organs, and that prune belly valves when present are intrinsic components of the mesodermal defect of the prune belly syndrome urethra.

Fetus↗
PubMed1994

Effect of protein energy malnutrition on the lipid composition and leucine uptake of small intestinal brush border vesicles of growing rhesus monkeys.

Mild to moderate protein energy malnutrition (PEM) was induced in young developing rhesus monkeys by giving them half of the casein-based synthetic diet which was given to control animals. After a body weight reduction of 30-40%, the PEM animals were sacrificed. The small intestine was removed, flushed with ice-cold saline, everted and divided into equal proximal, middle and distal segments. Brush border membrane vesicles (BBMV) were prepared from all three segments and assayed for marker enzymes, e.g. sucrase and alkaline phosphatase, to assess their purity. Sucrase was found to be purified 23-fold and alkaline phosphatase 12-fold compared to the respective homogenates in all three parts. In PEM animals, uptake of [U-14C]L-leucine into the BBMV was diminished in all three segments and cholesterol and phospholipid levels also decreased significantly. As a result there was an elevation in the molar ratio of cholesterol to phospholipid, and the sphingomyelin: phosphatidylcholine molar ratio also increased. This signified a decrease in lipid fluidity and amino acid uptake in PEM in the small intestine. Histologically, a mild to moderate grade of partial villus atrophy was observed in the intestine. The diminished uptake and lipid fluidity of the membrane and the histological changes returned to their control values after nutritional rehabilitation.

Alkaline Phosphatase↗