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Biomedical subjects

Y Xie

Publications and source records attributed to Y Xie.

At least 109 records · Page 6Linked to original sources
PubMed2001

SCFA increase intestinal Na absorption by induction of NHE3 in rat colon and human intestinal C2/bbe cells.

Short-chain fatty acids (SCFA), produced by colonic bacterial flora fermentation of dietary carbohydrates, promote colonic Na absorption through mechanisms not well understood. We hypothesized that SCFA promote increased expression of apical membrane Na/H exchange (NHE), serving as luminal physiological cues for regulating colonic Na absorptive capacity. Studies were performed in human colonic C2/bbe (C2) monolayers and in vivo. In C2 cells exposed to butyrate, acetate, proprionate, or the poorly metabolized SCFA isobutyrate, apical membrane NHE3 activity and protein expression increased in a time- and concentration-dependent manner, whereas no changes were observed for NHE2. In contrast, no significant changes in brush-border hydrolase or villin expression were noted. Analogous to the in vitro findings, rats fed the soluble fiber pectin exhibited a time-dependent increase in colonic NHE3, but not NHE2, protein, mRNA, and brush-border activity. These changes were region-specific, as no changes were observed in the ileum. We conclude that luminal SCFA are important physiological cues for regulating colonic Na absorptive function, allowing the colon to adapt to chronic changes in dietary carbohydrate and Na loads.

Animals↗
PubMed2001

Molecular cloning and characterization of a novel peptidylprolyl isomerase (cyclophilin)-like gene (PPIL3) from human fetal brain.

During the large-scale sequencing analysis of a human fetal brain cDNA library, we isolated two cDNA clones encoding two novel proteins, which show 52% and 72% identity to the cyclophilin isoform 10 of C. elegans, respectively. Sequence analysis revealed these two cDNA clones are two different splicing variants of a novel cyclophilin-like gene (PPIL3). The PPIL3 gene was identified on a completely sequenced BAC (GenBank accession AC005037) from chromosome 2q33 between STS markers stSG2762 (proximal) and SHGC-3074 (distal), oriented toward the telomere. The PPIL3 gene consisted of eight exons spanning more than 18 kb of genomic DNA. RT-PCR analysis indicated that PPIL3 was ubiquitously expressed in adult human tissues.

5' Untranslated Regions↗
PubMed2001

Molecular cloning, structure and expression of a novel nuclear RNA-binding cyclophilin-like gene (PPIL4) from human fetal brain.

The cyclophilins are members of a highly conserved, ubiquitous family, and play an important role in protein folding, immunosuppression by cyclosporin A (CsA), and infection of HIV-1 virions. Here we report that a novel member of the cyclophilin family, PPIL4, was cloned and identified during the large-scale sequencing analysis from a human fetal brain cDNA library. The PPIL4 gene encodes a protein which shares 96% amino acid identity with a protein encoded by a putative gene recently cloned from several different early stages of mouse embryo, and its homologues are found in several other organisms. According to bioinformatics analysis, the PPIL4 gene was found to be located in chromosome 6q24-->q25. Besides the PPIase motif, PPIL4 also has an RNA recognition motif (RRM), a pair of bipartite nuclear targeting sequences, and a lysine rich domain. RT-PCR analysis indicated that PPIL4 gene expression is abundant in kidney but has a ubiquitously low expression pattern in other human adult tissues.

Amino Acid Motifs↗
PubMed2001

Molecular cloning and characterization of a novel human gene (HSPBAP1) from human fetal brain.

Rat PASS1 is a novel protein binding specifically to hsp27 and thus plays a role in regulating stress response in the living cell. Here we report on a human homologue of PASS1, encoded by the gene HSPBAP1. The gene was cloned and identified during a large-scale sequencing analysis of a human fetal brain cDNA library. The human protein shared 80% amino acid identity with rat PASS1. According to bioinformatics analysis, the HSPBAP1 gene is located on chromosome 3q21. RT-PCR analysis indicated that HSPBAP1 was abundant in thymus and pancreas but had a ubiquitously low expression pattern in other human adult tissues except for brain where it was absent.

Amino Acid Sequence↗
PubMed2001

Inhibition of PYK2-induced actin cytoskeleton reorganization, PYK2 autophosphorylation and focal adhesion targeting by FAK.

Focal adhesion kinase (FAK) and proline-rich tyrosine kinase 2 (PYK2) are structurally related tyrosine kinases. They are implicated in regulating actin cytoskeleton organization, a process critical for cell migration, mitosis and tumor metastasis. In this paper, we demonstrate that, although both PYK2 and FAK were expressed and colocalized at focal adhesions in fibroblasts, microinjection of PYK2, but not FAK, in Swiss 3T3 fibroblastic cells led to reorganization of focal adhesions and cell rounding. PYK2-mediated actin cytoskeleton reorganization required the PYK2 N terminus, the focal adhesion targeting (FAT) domain, catalytic activity and autophosphorylation. Remarkably, FAK suppressed PYK2-mediated reorganization of focal adhesions and cell rounding. In addition, FAK inhibited PYK2 autophosphorylation and focal adhesion targeting, which might contribute to FAK-mediated suppression of PYK2's phenotypes. Further analyses demonstrated that the inhibition of PYK2 autophosphorylation required the FAK N terminus but not FAK tyrosine phosphorylation. The FAK FAT domain seemed to be critical for FAK-mediated suppression of PYK2 focal adhesion targeting. Taken together, these results demonstrate that FAK could inhibit PYK2 autophosphorylation, focal adhesion targeting and actin cytoskeleton reorganization, suggesting that the balance between FAK and PYK2 tyrosine kinases is important for regulating cellular morphology, cell migration and cell growth.

Actins↗
PubMed2001

Element concentrations in urine of patients suffering from chronic arsenic poisoning.

In order to know the element levels in the urine of patients with chronic arsenic poisoning caused by arsenic assimilated from burning coal via air and food, we investigated various elements in the urine of 16 patients with this disease and 16 controls living in the same county in Guizhou Province of China. Concentrations of 25 elements (Al, As, Ba, Be, Bi, Ca, Cd, Cr, Cu, Fe, Ga, Mg, Mn, Mo, Ni, P, Pb, Rb, Sb, Se, Sn, Sr, Ti, V and Zn) were determined by an inductively coupled plasma mass spectrometer or an inductively coupled plasma atomic emission spectrometer. The average concentrations of Cu, Ga and Sn as well as As in the patients were significantly higher, and those of Cr, Rb, Sr and Ti in the patients were significantly lower than the control values. Al, Ba, Mn, Ni and Se were under detection limit in the patients, though they could be detected in the controls. There were no positive correlations between the concentration of As and the concentrations of other elements, including Cu, Ga and Sn in the patients. The results of this study suggest that As from burning coal might influence the urinary excretion of some elements.

Adult↗
PubMed2001

Antihepatoma effect of alpha-fetoprotein antisense phosphorothioate oligodeoxyribonucleotides in vitro and in mice.

AIM: To evaluate antihepatoma effect of antisense phosphorothioate oligodeoxyribonucleotides (S-ODNs) targeted to alpha-fetoprotein (AFP) genes in vitro and in nude mice. METHODS: AFP gene expression was examined by immunocytochemical method or enzyme-linked immunosorbent assay. Effect of S-ODNs on SMMC-7721 human hepatoma cell growth in vitro was determined using microculture tetrazolium assay. In vitro antitumor activities of S-ODNs were monitored by measuring tumor weight differences in treated and control mice bearing SMMC-7721 xenografts. Induction of cell apoptosis was evaluated by fluorescence-activated cell sorter (FACS) analysis. RESULTS: Antisense S-ODN treatment led to reduced AFP gene expression. Specific antisense S-ODNs, but not control S-ODNs, inhibited the growth of hepatoma cells in vitro. In vitro, only antisense S-ODNs exhibited obvious antitumor activities. FACS analysis revealed that the growth inhibition by antisense S-ODNs was associated with their cell apoptosis induction. CONCLUSION: Antisense S-ODNs targeted to AFP genes inhibit the growth of human hepatoma cells and solid hepatoma, which is related to their cell apoptosis induction.

Animals↗
PubMed2001

Solution structure of cytochrome b(5) mutant (E44/48/56A/D60A) and its interaction with cytochrome c.

Using 1617 meaningful NOEs with 188 pseudocontact shifts, a family of 35 conformers of oxidized bovine microsomal cytochrome b5 mutant (E44/48/56A/D60A) has been obtained and is characterized by good resolution (rmsd to the mean structure are 0.047 +/- 0.007 nm and 0.095 +/- 0.008 nm for backbone and heavy atoms, respectively). The solution structure of the mutant, when compared with the X-ray structure of wild-type cytochrome b(5), has no significant changes in the whole folding and secondary structure. The binding between cytochrome b(5) and cytochrome c shows that the association constant of the mutant-cytochrome c complex is much lower than the one for wild-type complex (2.2 x 10(4) M(-1) vs. 5.1 x 10(3) M(-1)). The result suggests the four acidic residues have substantial effects on the formation of the complex between cytochrome b(5) and cytochrome c, and therefore it is concluded reasonably that the electrostatic interaction plays an important role in maintaining the stability and specificity of the complex formed. The competition between the ferricytochrome b(5) mutant and [Cr(oxalate)(3)](3-) for ferricytochrome c shows that site III of cytochrome c, which is a strong binding site to wild-type cytochrome b(5), still binds to the mutant with relatively weaker strength. Our results indicate that certain bonding geometries do occur in the interaction between the present mutant and cytochrome c and these geometries, which should be quite different from the ones of the Salemme and Northrup models.

Amino Acid Sequence↗
PubMed2001

[Study on the expression of pig zona pellucida-3 beta excluding N-terminus signal peptide and C-terminus transmembrance-like domain in Escherichia coli].

Pig oocytes are surrounded by an acellular translucent envelope-zona pellucida(pZP), which is comprised of three biochemically and immunologically distinct glycoproteins(pZP1, pZP3 alpha and pZP3 beta). Due to the cross-reactivity of anti-pZP3 beta antibodies with human ZP in vitro, pZP3 beta has been considered as potential one of immunogens for developing human contraceptive vaccine. In order to express pZP3 beta directly in E. coli; we amplified the core fragment of pZP3 beta cDNA by PCR that was deleted 5'- and 3'-terminal sequences of coding for signal peptide and transmembrane-like domain. The DNA sequenced EcoRI and SalI restriced core fragment was cloned in a frame downstream of PRPL promoter in the pBV221 vector. SDS-PAGE analysis showed that pZP3 beta protein was expressed especially in E. coli after thermal induction, which the expression band displayed the molecular weight of about 38 kD matching with its deduced molecular weight(36.5 kD). In addition, the specially expressed protein band on SDS-PAGE gel showed specific immunological reaction with anti-pig ZP IgGs of rabbit in Western blot.

Animals↗
PubMed2001

Molecular characterization of a novel defective DNA isolated from tobacco tissues infected with tobacco leaf curl virus.

Defective DNA of tobacco leaf curl virus (TLCV) was identified in TLCV-infected tobacco plants. The defective DNA was cloned and sequenced. The sequence showed it was about half the size of the TLCV DNA-A, and was derived from TLCV DNA-A by a large deletion. The defective DNA contained the intergenic region and part of the AC1 (Rep) gene of TLCV, and also novel open reading frames (ORFs). The immunotrapping tests showed the defective DNA was associated with geminate particles, suggesting it could be encapsidated in virus particles. It was transmitted, along with full-length DNA-A, to tobacco plants by grafting and whitefly (Bemisia tabaci).

Animals↗
PubMed2001

[Intron 44 is not the most unstable intron in the "central deletion hot spot" of dystrophin gene].

OBJECTIVE: To understand the distributional characteristics of dystrophin gene deletion breakpoints in "central deletion hot spot" and analyze the instability of introns 44-51 after excluding the effect of intron's length. METHODS: Fifty-nine Duchenne/Becker muscular dystrophy(DMD/BMD) patients were detected by polymerase chain reactions with the primers to amplify exons 44-52 of dystrophin gene. The amount of actual breakpoints, expected breakpoints according to its length, and the ratios of actual breakpoints to expected values(A/E) for introns 44-51 were calculated respectively. RESULTS: In "central deletion hot spot", about 30.8% of breakpoints fell in intron 44, about 23.1%, 17.9%, 10.3%, 10.3% of breakpoints fell in introns 50,51, 45, 48, respectively. But the amount of actual breakpoints of intron 44 was less than that of expected breakpoints according to its length, the ratio of A/E was 0.7. The amount of actual breakpoints of introns 48, 50, 51, 45 were more than that of length expected value. The ratios of A/E were 2.7, 2.0, 1.9, 1.1, respectively. CONCLUSION: Intron 44 is more stable than the whole molecular region of "central deletion hot spot". Introns 48, 50 and 51 are comparatively instable in "central deletion hot spot".

Dystrophin↗
PubMed2001

[Lignans from Schisandra propinqua (Wall.) Hook. f. et Thoms].

Three dibenzocyclooctadiene lignans were isolated from the stems of Schisandra propinqua (Wall.) Hook.f.et Thoms. Their structures were identified as interiotherin A (I), benzoylisogomisin O (II) and gomisin G (III) by spectroscopic analysis. Compound I was first discovered in Schisandra genus. Compounds II and III were originally isolated from S. propinqua.

Lignans↗
PubMed2001

Cytoplasmic expression of ribozyme in zebrafish using a T7 autogene system.

A cytoplasmic ribozyme expression system, based on codelivery of a ribozyme vector, a T7 autogene vector, and T7 RNA polymerase (RNAP), has been developed and used to generate a specific phenotype in zebrafish by targeting a no tail (ntl) mRNA. The expression of the no tail ribozyme sequence is under the control of a tandem of two promoters: The T7 promoter and an adenoviral va 1 (pol III) promoter. The coinjection of the ribozyme vector pT7vaRz, the T7 autogene vector pT7T7, and the T7 RNAP resulted in rapid synthesis of the ribozyme against the ntl mRNA in the cytoplasm of the injected zebrafish embryos, generating no tail phenotypes in up to 10-20% of the injected embryos. The phenotypic change rates have been found to be related to the concentrations of the plasmid vectors and T7 RNAP injected and to the ratios of the three injected components. This cytoplasmic ribozyme expression system may be useful for efficiently targeting other mRNA and for various biomedical applications. These potential applications may include rapid identification of biological functions of novel genes from zebrafish and humans based on partial gene sequence information and gene therapy of genetic and acquired diseases.

Adenoviridae↗
PubMed2001

Pro- and anti-inflammatory forms of interleukin-1 in the tear fluid and conjunctiva of patients with dry-eye disease.

PURPOSE: To compare the expression of the pro- and anti-inflammatory forms of interleukin (IL)-1 in the tear fluid and conjunctival epithelium of normal eyes and those with dry-eye disease. METHODS: The concentrations of IL-1 alpha, IL-1 beta (precursor and mature forms), and IL-1 receptor antagonist (IL-1Ra) were measured by ELISA in tear fluid samples obtained from normal individuals and patients with dry eye who had rosacea-associated meibomian gland disease (MGD) or Sjögren's syndrome (SS) aqueous tear deficiency (ATD). These cytokines were also measured in normal tear fluid before and after nasal stimulation to induce reflex tearing. The relative expression of these cytokines was evaluated in conjunctival impression cytology specimens and conjunctival biopsy tissue obtained from normal subjects and SS ATD-affected patients using immunofluorescent staining. Matrix metalloproteinase (MMP)-9 concentration and activity in the tear fluid were evaluated with gelatin zymography and with an MMP-9 activity assay kit, respectively. RESULTS: Compared with normal subjects, the concentration of IL-1 alpha and mature IL-1 beta in the tear fluid was increased, and the concentration of precursor IL-1 beta was decreased in patients with MGD (P < 0.05, P = 0.02, and P < 0.01, respectively) and SS ATD (P < 0.001, P = 0.02, and P < 0.001, respectively). There was no significant change in the concentration of IL-1 alpha, precursor IL-1 beta, and IL-1Ra in reflex tear fluid, indicating that the lacrimal glands may secrete these cytokines. The activity of MMP-9, a physiological activator of IL-1 beta, was significantly elevated in the tear fluid of both dry-eye groups compared with normal subjects. A strong positive correlation was observed between the intensity of corneal fluorescein staining and the tear fluid IL-1 alpha concentration (r(2) = 0.17, P < 0.02) and the mature-to-precursor IL-1 beta ratio (r(2) = 0.46, P < 0.001). Positive immunofluorescent staining for IL-1 alpha, mature IL-1 beta, and IL-1Ra was observed in a significantly greater percentage of conjunctival cytology specimens from eyes with SS ATD than in those from normal eyes (P < 0.01 for IL-1 alpha, P < 0.009 for mature IL-1 beta, and P < 0.05 for IL-1Ra). CONCLUSIONS: Dry-eye disease is accompanied by an increase in the proinflammatory forms of IL-1 (IL-1 alpha and mature IL-1 beta) and a decrease in the biologically inactive precursor IL-1 beta in tear fluid. Increased protease activity on the ocular surface may be one mechanism by which precursor IL-1 beta is cleaved to the mature, biologically active form. The conjunctival epithelium appears to be one source of the increased concentration of IL-1 in the tear fluid of patients with dry-eye disease. These results suggest that IL-1 may play a key role in the pathogenesis of keratoconjunctivitis sicca.

Adult↗
PubMed2001

[Degradation of methamidophos by Saccharomyces rouxii WY-3].

A strain of Yeast WY-3 was isolated from wastewater sample. It is capable of utilizing methamidophos as sole nitrogen and phosphorus sources, and also capable of utilizing methylamine, ethylamine and ammonium sulfate as nitrogen sources except nitrate and hydroxylamine. The yeast could grow in medinm containing 60% glucose and was identified as Saccharomyces rouxii WY-3. The strain contains a high active acid phosphatase. The crude enzyme was applied to a plate of polyacrylanide gel for electrophoresis, then activity was detected as white single band. Inhibiting test showed that sodium fluoride could seriously inhibit the activity of acid phosphatase to release phosphorus from methamidophos, wherease it make no effect on deamination of the strain WY-3 from methamidophos. After methamidophos was degraded by strain WY-3, toxity of the pesiticide reduced obviously, and its portion intermediate, methanol and inorganic phosphorus, were deteted.

Biodegradation, Environmental↗
PubMed2001

[Dynamic change and expression of matrix metalloproteinase-2, -9 in alcoholic liver disease in rats].

OBJECTIVE: To evaluate the dynamic change and expression of matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) in alcoholic liver disease in rats. METHODS: Alcoholic liver disease rat model was established by gavage. The expression of MMP-2 and MMP-9 was studied by immunohistochemistry, and the result was analyzed by picture quantitative analysis technique. RESULTS: The expression of MMP-2 and MMP-9 was significantly higher in rats of model group than that of control group (P<0.05). The level of MMP-2 and MMP-9 increased gradually with the progress of alcoholic liver disease. Immunoreactive MMP-2 was expressed in endothelial cells of hepatic artery and portal vein, sinusoidal endothelial cells and sinusoidal cells. Immunoreactive MMP-9 was observed in sinusoidal cells and hepatic cells around the vein. CONCLUSIONS: MMP-2 and MMP-9 increa with the progress of alcoholic liver disease. They might be involved in the development of alcoholic liver disease.

Animals↗