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Biomedical subjects

A Pandey

Publications and source records attributed to A Pandey.

At least 91 records · Page 5Linked to original sources
PubMed1996

Anterior sagittal anorectoplasty for anorectal malformations and perineal trauma in the female child.

Vestibular fistula and perineal ectopic anus are the most common anorectal malformations in female children. Anterior saggital anorectoplasty (ASARP) was used to treat 416 patients with these anomalies, as well as cases of perineal canal and third-degree perineal tear, during a 20 year period. Preliminary colostomy was performed in only four patients, who had a perineal tear. For ASARP, a midline incision was made and the rectum was separated from the vagina and placed in the center of the sphincteric muscle complex. The perineal body was reconstructed, and normal appearance of the perineum was achieved. Six patients had complications postoperatively (4 had secondary hemorrhage, 2 had wound infection). One patient with hemorrhage and one with infection required laying open of the wound and revision surgery after 12 weeks. Both recovered well. Of the 416 patients, 397 returned for follow-up 12 weeks after the surgery. Of these, 390 had a normal-looking perineum and normal defecation. Of the remaining seven patients, three had retraction of the rectum, one had recurrence of the fistula, and another had acquired perineal canal. These five children required revision ASARP and recovered successfully. The other two patients had mucosal prolapse, which reduced spontaneously. Three hundred twenty-six children of the 416 patients have had follow-up beyond the age of 3 years. Of these, 291 had normal bowel habits without the use of laxatives. Of the other 35, four had fecal impaction of unknown etiology, which was managed conservatively, 6 had anal stenosis (four underwent posterior Barrow's flap interposition and two responded to dilatation), and 25 had a posterior ledge that caused constipation and required cutback. Overall, eight patients (1.9%) required revision ASARP and 40 others (9.8%) had minor complications. This operation provides consistently good results, and the authors recommend it for the management of anorectal malformations and perineal trauma in female children.

Adolescent↗
PubMed1996

Coloplasty for congenital short colon.

Seventy-two patients with complete short colon (CSC) were treated at the authors' institution between 1971 and 1994. Initially, one-stage coloplasty with abdominoperineal pull-through was performed in 10 neonates, with a 50% survival rate. The subsequent 62 patients had staged management in which a window colostomy was performed at the time of presentation. Of the 50 survivors in this group, 20 had coloplasty with a abdominoperineal or sacroabdominoperineal pull-through by June 1994. A protective ileostomy was done at the time of coloplasty in 10 patients, and was closed 6 to 12 weeks later. Two of the 20 patients who had staged reconstruction died because of complications; the others recovered well. The overall survival rate after coloplasty was 76.7%. Eighteen of the 23 survivors have had follow-up for up to 8 years. They have shown normal growth and good continence and have been free of significant long-term complications. The other 30 patients are awaiting definitive surgery. A staged management plan is advocated for complete short colon because it provides consistent results and good quality of life.

Anus, Imperforate↗
PubMed1996

Purification and characterization of glucoamylase produced by Aspergillus niger in solid state fermentation.

Glucoamylases produced by Aspergillus niger grown on wheat brain in solid cultures were purified. Four different forms, GA I, GA I', GA II and GA III, were found having apparent molecular weights of 112,000, 104,000, and 74,000 and 61,000 Da respectively. The enzymes are glycoproteins with a carbohydrate content of 16%, and optimal activity at 60 degrees C and pH 4.4. Activity was strongly inhibited by Hg2+ while Mn2+ and Fe2+ were stimulatory. The Km values for the degradation of starch and maltose were 3.5 and 7.8 mg ml-1, respectively.

Aspergillus niger↗
PubMed1996

Inactivation of yeast glutathione reductase by O-phthalaldehyde.

Yeast glutathione reductase was inactivated by the bifunctional reagent, o-phthalaldehyde. The initial rate of inactivation followed pseudo-first order kinetics. Fluorescence spectral properties of modified enzyme indicated the formation of an isoindole derivative from cysteine and lyaine residues present in close proximity as shown by typical fluorescence emission and excitation maximum at 410 nm and 337 nm, respectively. The fluorescence spectral studies with o-phthalaldehyde in the presence and absence of N-ethylmaleimide indicated that both the inhibitors react with the same cysteine residue, which is non-essential for enzyme activity. The coenzyme NADPH did not protect the enzyme against the o-phthalaldehyde reaction while oxidised glutathione prevented o-phthalaldehyde inactivation. This could be due to reaction of the amino group of glutathione with o-phthalaldehyde. Stoichiometry of the reaction showed that the formation of approximately 2 isoindole derivatives per subunit of glutathione reductase is accompanied by 75% loss of activity. The results suggest that o-phthalaldehyde binds to non-essential cysteine and lysine residues present in close proximity which results in conformational changes leading to enzyme inactivation.

Cysteine↗
PubMed1995

Chromosomal localization of the mouse Src-like adapter protein (Slap) gene and its putative human homolog SLA.

Molecules containing Src-homology 2 (SH2) and Src-homology 3 (SH3) domains are critical components of signal transduction pathways that serve to relay signals originating from the cell surface to the interior of the cell. Src-like adapter protein (SLAP) is a recently described adapter protein that binds activated the Eck receptor protein-tyrosine kinase. Although SLAP bears a striking homology to the SH3 and SH2 domains of the Src family of nonreceptor tyrosine kinases, it does not contain a tyrosine kinase catalytic domain. In this report, the Slap gene was mapped by linkage analysis to mouse chromosome 15, while its putative human homolog (SLA) was identified and mapped to human 8q22.3-qter using a panel of somatic cell hybrids.

Adaptor Proteins, Signal Transducing↗
PubMed1995

The Ret receptor protein tyrosine kinase associates with the SH2-containing adapter protein Grb10.

Ret is a receptor protein tyrosine kinase that has been implicated in the development of the enteric nervous, endocrine, and renal systems. Mutations associated with multiple endocrine neoplasia types 2A and 2B (MEN 2A and 2B) have been shown to activate the intrinsic kinase and transforming ability of ret (Santoro, M., Carlomagno, F., Romano, A., Bottaro, D. P., Dathan, N. A., Grieco, M., Fusco, A., Vecchio, G., Matoskova, B., Kraus, M. H., and Paolo DiFiore, P. (1995) Science 267, 381-383). Using the cytoplasmic domain of Ret as bait in a yeast two-hybrid screen of a mouse embryonic library, it was discovered that the src homology 2 (SH2) domain containing protein Grb10 bound Ret. Grb10 belongs to an emerging family of SH2 containing adapter proteins, the prototypical member being Grb7. Using glutathione S-transferase fusion proteins, it was demonstrated that the SH2 domain of Grb10 specifically interacted with Ret. Additionally, using an EGFR/Ret chimera, it was shown that Grb10 bound Ret in an activation dependent manner in vivo. This is the first description of a receptor protein tyrosine kinase that utilizes Grb10 as a signaling intermediate.

Animals↗
PubMed1995

Cell signalling. Receptor orphans find a family.

A family of ligands has been identified for the largest group of receptor protein-tyrosine kinases--the hitherto 'orphan' EPH receptor subfamily--and the functions of these receptors and ligands are starting to be elucidated.

Amino Acid Sequence↗
PubMed1995

Characterization of a novel Src-like adapter protein that associates with the Eck receptor tyrosine kinase.

The Eph family of receptor protein tyrosine kinases (RPTKs) is the largest family of RPTKs. The signal transduction pathways initiated by this family have only recently begun to be explored. Using a yeast two-hybrid screen to identify molecules that interact with the cytoplasmic domain of Eck, it was previously shown that activated Eck RPTK bound to and stimulated phosphatidylinositol 3-kinase (Pandey, A., Lazar, D.F., Saltiel, A. R., and Dixit, V.M. (1994) J. Biol. Chem. 269, 30154-30157). Also isolated from this same screen was a novel protein containing SH3 and SH2 adapter modules that had striking homology to those found in the Src family of non-receptor tyrosine kinases. However, unlike other Src family members, it lacked a catalytic tyrosine kinase domain. Hence, this protein was designated SLAP for Src-like adapter protein. Using glutathione S-transferase fusion Proteins, it was demonstrated that SLAP bound to activated Eck receptor tyrosine kinase. Therefore, SLAP is a novel candidate downstream signaling intermediate and the first member of the Src family that resembles an adapter molecule.

Adaptor Proteins, Signal Transducing↗
PubMed1995

Role of B61, the ligand for the Eck receptor tyrosine kinase, in TNF-alpha-induced angiogenesis.

B61, a cytokine-inducible endothelial gene product, is the ligand for the Eck receptor protein tyrosine kinase (RPTK). Expression of a B61-immunoglobulin chimera showed that B61 could act as an angiogenic factor in vivo and a chemoattractant for endothelial cells in vitro. The Eck RPTK was activated by tumor necrosis factor-alpha (TNF-alpha) through induction of B61, and an antibody to B61 attenuated angiogenesis induced by TNF-alpha but not by basic fibroblast growth factor. This finding suggests the existence of an autocrine or paracrine loop involving activation of the Eck RPTK by its inducible ligand B61 after an inflammatory stimulus, the net effect of which would be to promote angiogenesis, a hallmark of chronic inflammation.

Animals↗
PubMed1995

Characterization of B61, the ligand for the Eck receptor protein-tyrosine kinase.

B61 was originally described as a novel secreted tumor necrosis factor-alpha-inducible gene product in endothelial cells (Holzman, L. B., Marks, R. M., and Dixit, V. M. (1990) Mol. Cell. Biol. 10, 5830-5838). It was recently discovered that soluble recombinant B61 could serve as a ligand for the Eck receptor protein-tyrosine kinase, a member of the Eph/Eck subfamily of receptor protein-tyrosine kinases (Bartley, T.D., Hunt, R. W., Welcher, A. A., Boyle, W. J., Parker, V. P., Lindberg, R. A., Lu, H. S., Colombero, A. M., Elliott, R. L., Guthrie, R. A., Holst, P. L., Skrine, J. D., Toso, R. J., Zhang, M., Fernandez, E., Trail, G., Yarnum, B., Yarden, Y., Hunter, T., and Fox, G. M. (1994) Nature 368, 558-560). We now show that B61 can also exist as a cell surface glycosylphosphatidyl-inositol-linked protein that is capable of activating the Eck receptor protein-tyrosine kinase, the first such report of a receptor protein-tyrosine kinase ligand that is glycosylphosphatidylinositol-linked. In addition, the expression patterns of B61 and Eck during mouse ontogeny were determined by in situ hybridization. Both were found to be highly expressed in the developing lung and gut, while Eck was preferentially expressed in the thymus. Finally, the gene for B61 was localized to a specific position on mouse chromosome 3 by interspecific back-cross analysis.

Animals↗
PubMed1995

cDNA cloning and characterization of a Cek7 receptor protein-tyrosine kinase ligand that is identical to the ligand (ELF-1) for the Mek-4 and Sek receptor protein-tyrosine kinases.

We have isolated a murine cDNA encoding a ligand for the Cek7 receptor protein-tyrosine kinase (RPTK), a member of the Eph/Eck RPTK subfamily. Sequence analysis predicts an open reading frame of 209 amino acids with a predicted molecular mass of 24 kDa. The Cek7 ligand shows a 48% sequence identity at the protein level to B61, a ligand for the related Eck RPTK, 30% to the Cek5 ligand, 59% to the recently cloned Ehk1-L, and identity to ELF-1, a recently described ligand for the Mek4 and Sek RPTKs. The expressed Cek7 ligand is functionally active as it induces autophosphorylation of the Cek7 RPTK.

Amino Acid Sequence↗
PubMed1995

Some analytical models to estimate maternal age at birth using age-specific fertility rates.

"A class of analytical models to study the distribution of maternal age at different births from the data on age-specific fertility rates has been presented. Deriving the distributions and means of maternal age at birth of any specific order, final parity and at next-to-last birth, we have extended the approach to estimate parity progression ratios and the ultimate parity distribution of women in the population.... We illustrate computations of various components of the model expressions with the current fertility experiences of the United States for 1970."

Age Factors↗
PubMed1995

Essential lysine residue in glutathione reductase: chemical modification by pyridoxal 5'-phosphate.

Yeast glutathione reductase was inactivated by pyridoxal 5'-phosphate. The inhibition was reversed by dilution. The enzyme-pyridoxal 5'-phosphate complex on reduction with sodium borohydride gave a characteristic absorption maximum at 325 nm and fluorescence maximum at 395 nm when exciated at 325 nm. These results were consistent with the reaction of epsilon-amino group of lysine residue of the enzyme with pyridoxal 5'-phosphate. The enzyme was protected against pyridoxal 5'-phosphate inhibition by NADP indicating thereby that the essential lysine residues are present during the NADP binding site.

Adenosine Monophosphate↗
PubMed1994

Activation of the Eck receptor protein tyrosine kinase stimulates phosphatidylinositol 3-kinase activity.

The Eph/Eck subfamily of receptor protein tyrosine kinases is currently the largest subfamily of receptor protein tyrosine kinases with a dozen members (Van der Geer, P., Hunter, T., and Lindberg, R. A. (1994) Annu. Rev. Cell Biol. 10, 251-337). Using the cytoplasmic domain of Eck as bait in a yeast two-hybrid screen of mouse embryonic and T-cell cDNA libraries, it was discovered that the p85 subunit of phosphatidylinositol 3-kinase bound Eck. Further, using glutathione S-transferase fusion proteins, it was found that the C-terminal src homology 2 domain of the p85 subunit specifically interacted with Eck. Additionally, Eck coimmunoprecipitated with p85 in ligand activated cells confirming their interaction in vivo. In keeping with the above observations, activation of Eck by its ligand, B61, increased phosphatidylinositol 3-kinase activity. This is the first description of a signal transduction pathway initiated by any member of the Eph/Eck family.

Animals↗
PubMed1994

cDNA cloning and characterization of a ligand for the Cek5 receptor protein-tyrosine kinase.

We have isolated a murine cDNA encoding a ligand for the Cek5 receptor protein-tyrosine kinase (RPTK), a member of the Eph/Eck RPTK subfamily. Sequence analysis predicts an open reading frame of 345 amino acids with a predicted molecular mass of 38 kDa. Metabolic labeling and immunoprecipitation of cells transfected with a cDNA encoding the Cek5 ligand revealed the mature protein to have an apparent molecular mass of 45 kDa. The extracellular domain of the Cek5 ligand shows a 27% sequence identity at the protein level to B61, a ligand for the related Eck RPTK (Bartley, T. D., et al. (1994) Nature 368, 558-560). Consistent with the presence of a transmembrane domain, flow cytometry analysis revealed the Cek5 ligand to be expressed on the cell surface. The expressed Cek5 ligand is functionally active as it induces autophosphorylation of the Cek5 RPTK.

Amino Acid Sequence↗
PubMed1994

Implications of changes in family dynamics in India: 1971-1988.

"This paper examines the implications of demographic transition...on kinship relationships in India during 1971-1988. Three simulations based on the schedules of fertility and mortality of India during 1971, 1981, and 1988 have been undertaken. The kinship size constitutes parents, grand parents, siblings (brothers and sisters) and children. Improved mortality condition has increased the percentage of kins in ancestor generation. The percentage of kins in ancestor generation was 15 percent in 1988 as compared to 8.5 percent in 1971.... The increase in the percent of kins in ancestor generation and the support ratio obviously shows the aging of the population."

Asia↗