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Biomedical subjects

W Xiong

Publications and source records attributed to W Xiong.

84 records · Page 5Linked to original sources
PubMed1991

Reliability and validity of the Chinese versions of the Scales for Assessment of Positive and Negative Symptoms.

This 4-center study assesses the reliability and validity of the Chinese versions of the Scale for Assessment of Positive Symptoms and the Scale for Assessment of Negative Symptoms. Interrater reliability, short-term test-retest reliability, and internal consistency were excellent; intraclass correlation coefficients and Cronbach alphas for the overall scores were all over 0.8. The strong correlation of the scales with an independently assessed parallel measure (the Chinese version of the Brief Psychiatric Rating Scale) and the separate positive and negative factors found with principal components analysis confirm the construct validity of the instruments. These findings demonstrate the importance of culturally sensitive revision and rigorous psychometric evaluation of Western instruments prior to their use in non-Western cultures.

Adolescent↗
PubMed1990

Tissue kallikrein-binding protein is a serpin. I. Purification, characterization, and distribution in normotensive and spontaneously hypertensive rats.

Kallikrein-binding protein was purified to apparent homogeneity from rat serum by Affi-Gel Blue, DEAE-Sepharose CL-6B, Sephacryl S-200 chromatography, and preparative gel electrophoresis or high performance liquid chromatography. The purified protein migrates as a single band of 60 kDa in a sodium dodecyl sulfate-polyacrylamide gel under reducing conditions. It is an acidic protein with isoelectric points ranging from 4.2 to 4.6. The amino terminus of the binding protein is an Asp residue as determined by sequence analysis. It forms a 92-kDa sodium dodecyl sulfatestable complex with kallikrein with a t1/2 of 18 min. Western blot and radioimmunoassay showed a distribution of the kallikrein-binding protein in serum, urine, and various tissues with a 5-10-fold lower amount in spontaneously hypertensive rats (SHR) than in Wistar-Kyoto rats (WKY). A full length cDNA clone encoding the kallikrein-binding protein was isolated from a rat liver cDNA library by immunoscreening and the translated amino acid sequence matches the amino-terminal 29-amino acid sequence of the binding protein. The cDNA sequence shares 68.8% identity with human alpha 1-antichymotrypsin and is identical to that of a rat hepatic protein. Dot blot analysis shows that kallikrein-binding protein is expressed at high levels in the liver and at low levels in the lung, salivary gland, and kidney. Its mRNA level in the liver decreases by 2-fold after acute phase inflammation and is higher in male than in female rats. Genomic Southern blot analyses reveal restriction fragment length polymorphisms between SHR and WKY rats in the binding protein locus. The results indicate that rat kallikrein-binding protein belongs to the serpin superfamily and its level is significantly reduced in the spontaneously hypertensive rats.

Amino Acid Sequence↗
PubMed1990

Identification, purification, and localization of tissue kallikrein in rat heart.

A tissue kallikrein has been isolated from rat heart extracts by DEAE-Sepharose and aprotinin-affinity column chromatography. The purified cardiac enzyme has both N-tosyl-L-arginine methyl ester esterolytic and kinin-releasing activities, and displays parallelism with standard curves in a kallikrein radioimmunoassay, indicating it to have immunological identity with tissue kallikrein. The enzyme is inhibited by aprotinin, antipain, leupeptin and by high concentrations of soybean trypsin inhibitor, but stimulated by lima-bean or ovomucoid trypsin inhibitor and low concentrations of soybean trypsin inhibitor. By using a specific monoclonal antibody to tissue kallikrein in Western blot as well as active-site labelling with [14C]di-isopropyl fluorophosphate, the cardiac enzyme was identified as a protein of 38 kDa, a molecular mass identical with that of tissue kallikrein. Immunocytochemistry at the electron-microscopic level localized this enzyme to the sarcoplasmic reticulum and granules of rat atrial myocytes. Two cardiac kallikrein precursors, (38 and 40 kDa) were identified from the translation in vitro of heart mRNA by immunoprecipitation and electrophoresis of [35S]methionine-labelled cell-free translation products. Kallikrein mRNA in the rat heart was also demonstrated by dot-blot analysis using a tissue kallikrein cDNA probe. These results indicate that the tissue kallikrein gene is expressed in the rat heart and that the purified enzyme is indistinguishable from tissue kallikrein with respect to enzymic and immunological characteristics.

Animals↗
PubMed1990

Purification and characterization of a kallikrein-like T-kininogenase.

A T-kininogenase has been purified to homogeneity from rat submandibular gland extracts by DEAE-Sepharose chromatography and preparative gel electrophoresis. The purified protein has an apparent Mr of 28,000 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and splits into heavy and light chains with Mr of 22,000 and 6,000 in the presence of dithiothreitol. It is an acidic glycoprotein with pI of 4.65-4.75. The carbohydrate moiety is located on the light chain and binds concanavalin A and wheat germ agglutinin. The active site serine residue of the heavy chain is labeled with [14C]diisopropylfluorophosphate and visualized by fluorography. NH2-terminal amino acid sequences of the light and heavy chains reveal 74-84% identity to rat tissue kallikrein, tonin, and other kallikrein-related enzymes. The enzyme cleaves T-kininogen to release T-kinin which was separated by high performance liquid chromatography on a reverse phase C18 column and identified by a kinin radioimmunoassay. Its T-kininogenase but not N-tosyl-L-arginine methyl ester esterase activity can be enhanced 10-fold in the presence of dithiothreitol. The esterolytic activity of the enzyme is inhibited by soybean trypsin inhibitor, aprotinin, leupeptin, and antipain; whereas lima bean and ovomucoid trypsin inhibitors stimulate its activity. The enzyme is localized at the granular convoluted tubule and striated duct cells in rat submandibular glands by immunohistochemistry. The results indicate that T-kininogenase belongs to the group of structurally similar yet distinct kallikrein-like serine proteases.

Amino Acid Sequence↗
PubMed1989

Renal kallikrein mRNA localization by in situ hybridization.

Tissue kallikrein gene expression in rat kidney was examined by in situ hybridization histochemistry. A rat tissue kallikrein cDNA probe, 534 bases in length and complementary to the 3' end of kallikrein mRNA was first used in Northern blot analysis to demonstrate the existence of tissue kallikrein mRNA in rat kidney. Then, kallikrein mRNA's localization in rat kidney sections was studied in situ hybridization histochemistry using the same probe. Positive signals were concentrated in the renal cortex at the vascular pole of the glomeruli and to a lesser degree, the distal tubular cells. Prehybridization with the unlabeled probe can abolish the positive signal; the same result can also be achieved by pretreatment of the tissue section with ribonuclease. By using the same technique, tissue kallikrein mRNA was also localized in granular convoluted tubule and striated duct cells of rat submandibular gland. The results suggest a new site of renal kallikrein synthesis at the vascular pole of the glomerulus. These findings, coupled with the previous studies that tissue kallikrein can participate in activation and releasing of renin, raise a potential physiological role of kallikrein in renin release or prorenin processing at juxtaglomerular cells.

Animals↗
PubMed1988

Tissue distribution and kininogen gene expression after acute-phase inflammation.

A kinin-directed monoclonal antibody to kininogens has been developed by the fusion of murine myeloma cells with mouse splenocytes immunized with bradykinin-conjugated hemocyanin. The hybrid cells were screened by an enzyme-linked immunosorbent assay (ELISA) and a radioimmunoassay (RIA) for the secretion of antibodies to bradykinin. Ascitic fluids were produced and purified by a bradykinin-agarose affinity column. The monoclonal antibody (IgG1) bound to bradykinin, Lys-bradykinin, Met-Lys-bradykinin, and kininogens in ELISA. Further, this target-directed monoclonal antibody recognized purified low and high molecular weight bovine, human, or rat kininogens and T-kininogen in Western blotting. After turpentine-induced acute inflammation, rat kininogen levels increased dramatically in liver and serum as well as in the perfused pituitary, heart, lung, kidney, thymus, and other tissues, as identified by the kinin-directed kininogen antibody in Western blot analyses. The results were confirmed by measuring kinin equivalents of kininogens with a kinin RIA. During an induced inflammatory response, rat kininogens were localized immunohistochemically with the kinin-directed monoclonal antibody in parenchymal cells of liver, in acinar cells and some granular convoluted tubules of submandibular gland, and in the collecting tubules of kidney. Northern and cytoplasmic dot blot analyses using a kinin oligonucleotide probe showed that kininogen mRNA levels in liver but not in other tissues increase after turpentine-induced inflammation. The results indicated that rat kininogens are distributed in various tissues in addition to liver and only liver kininogen is induced by acute inflammation. The target-directed kininogen monoclonal antibody is a useful reagent for studying the structure, localization, and function of kininogens or any protein molecule containing the kinin moiety.

Acute-Phase Reaction↗
PubMedDate not supplied

Prolonged cold preservation promotes the recipient's cell participating in neointima formation but delays the later graft arteriosclerosis in rat model.

Chronic graft dysfunction is the greatest barrier to long-term graft survival, although the immediate outcome in organ transplantation has been greatly improved. Graft arteriosclerosis is a prominent feature of chronic graft dysfunction. Recipient progenitor cells have been shown to participate in neointimal development in graft arteriosclerosis. The present study investigated the role of recipient endothelial cells in the repair and remodeling after a cold preservation injury in an orthotopic cross-sex abdominal aortic allotransplantation model, namely female Wistar to male Sprague-Dawley rats. Grafts were preserved for 48 hours in 4 degrees C University of Wisconsin (UW) solution for a prolonged cold ischemia (PCI) group or preserved for <1 hour in the control group; or for <1 hour in the presence of feeding with cyclosporine (CyA). A direct in situ polymerase chain reaction (ISPCR) for the SRY gene showed SRY-marked endothelial and smooth muscle-like cells in neointima at 2 weeks in the PCI group, at 4 weeks in the control group, and rarely at 3 months in the CyA group. Staining by H&E showed the aortic graft intima to be thicker in the PCI than in the control group at 4 weeks, but thinning thereafter. The SRY-positive cells correlated with intimal thickness in the PCI and the control group (r = .801 and .825; P < .05 and <.05, respectively), but not in the CyA group (r = .247, P > .5). Our data suggest that prolonged cold preservation promotes recipient cell participation in graft arteriosclerosis after endothelium injury. The early neointimal formation via recipient cells incorporated into arteriosclerotic neointima may delay later intimal thickening. In the aortic allotransplantation model, prolonged cold ischemia may be beneficial for long-term graft survival due to early endothelial replacement. We hypothesize that controlled injury to the graft may serve as a new strategy for treatment of intimal thickening.

Animals↗