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Biomedical subjects

H Xu

Publications and source records attributed to H Xu.

At least 469 records · Page 26Linked to original sources
PubMed1998

Polymorphism of DXS102 locus in Chinese population and its application to gene diagnosis in hemophilia B family.

OBJECTIVE: To establish the polymorphism of DXS102 locus from Xq26.3-27.1 in Chinese population for the gene diagnosis in Hemophilia B family. METHODS: DNA was extracted from blood samples obtained from Shanghai unrelated volunteer donors with phenol-chloroform method. A total of 23x chromosomes (154 from females, 80 from males) were studied. A hemophilia B family in which a hemophilia B patient has received gene therapy was analyzed. The polymorphism of DXS102 locus in Chinese population was determined with amplified fragment length polymorphisms assay (Amp-FLP), denaturing polyacrylamide gel electrophoresis, silver stain detection. Short tandem repeats (STRs) linkage analysis was used to conduct gene diagnosis in hemophilia B family. RESULTS: Eight alleles were found at DXS102 locus, of which two alleles were first reported. The repeated number of AC dinucleotide ranges from 13 to 21. And the values of the observed heterozygosity, calculated heterozygosity and polymorphism information content(PIC) were 0.87, 0.80, 0.80 respectively. It was also found that the difference of the allele frequencies of DXS102 in Chinese and European populations was significant. By using the linkage analysis of the DXS102 locus, a family with a hemophilia B patient receiving gene therapy in 1994 was analyzed and meanwhile a carrier in that family was then detected. CONCLUSIONS: The polymorphism of DXS102 locus reveals significant difference between Chinese and European populations. DXS102 locus can be used as a promising marker for gene diagnosis in hemophilia B family.

Alleles↗
PubMed1998

[Comparative study on DNA abstraction of human tissues preserved by two different methods].

Comparative studies have been made on the effect of DNA abstraction of different human tissues preserved by different methods. The results showed that different human tissues preserved in 50% alcohol may have similar DNA abstraction effect for a relatively long time as frozen tissues. They have no significant difference (chi 2 < or = 0.21, P > or = 0.995). This preservation method has the advantage of simplicity, high DNA output and good effect, and is suitable for preserving tissues under special circumstances.

Alcohols↗
PubMed1998

[The relationship between different serological types of Pseudomonas aeruginosa strain in lower respiratory tract and its clinical significance].

OBJECTIVE: To explore the relationship between different serological types of pseudomonas aeruginose (PA) in sputum and its clinical significance. METHOD: PA was detected by Vitek-Ams GNI card and its sensitivity to 12 kinds of antibiotics was measured with GNS-GA, its different serological types were assayed with standard diagnostic serum of type 20. RESULT: 14 different serological types were isolated from 101 strains of PA in sputum (with the typed rate 84.2%). Among them, type 6, type 1, and type 3 were higher with 23.7%, 13.9% and 10.9% respectively. But another 15.8% of strains couldn't be differentiated, so called untyped PA group, among them 10 strains with mucoid-like colony (63% of this untyped group). Patients suffered with this group were older and were very seriously infected with higher mortality (13%). They often suffered from serious COPD and bronchiectasis. The sensitivities of all PA strains to antibiotics in vitro as follows: tobramycin 92.0%, ceftazidine 89.1%, ciprofloxacin 87.1%, ticarcillin 82.2%, and gentamycin 76.2%. Among 12 PA strains tested with imipenem sensitive test, only one strain of mucoid-like colony had been found resistant. CONCLUSION: Identification of serological type of PA can be used as an important method to make out if the infection comes from the same source, and for surveillance of hospital infection, and to show the main types of PA in some district. But the sensitivity of antibiotics in vitro is no definitive correlation with PA serological types. The disease infected with untyped PA strains have its clinically special characteristics and must be kept attention.

Adult↗
PubMed1998

[Cleft palate with problems of middle ears].

OBJECTIVE: To gain a clear idea of the function of middle ears and hearing loss in cleft palate. METHODS: 59 cleft palate cases, including 117 ears are investigated by tympanogram and hearing threshold. RESULTS: In 80.4% of patients the function of middle ears are abnormal. 59.4% ears are conductive hearing loss in various degrees. CONCLUSION: Function of middle ears in cleft palate should be regularly examined as early as possible. If it is secretory otitis media, the tympanostomy pressure equalization tubes should be inserted to compensate inadequate function of the eustachian tube so as to avoid adhesive otitis media. The methods for the prevention and reduction of the middle ear problems with cleft palate are also suggested.

Adolescent↗
PubMed1998

[Effect of dentin inorganic material during dentin bond].

OBJECTIVE: In order to investigated the effect of dentin inorganic material during dentin bond. METHODS: This study investigated the tensile bond strength (TBS) between 4-META/MMA-TBB resin and dentin treated with several dentin treating methods. RESULTS: When the dentin was treated with acid-salt pretreating solution system (APSS) consisting of 10% citric acid and 3% ferric chloride to remove smear layer, and then re-treated with NaOCl to resolve dentin collagen and reveal dentin inorganic material, TBS of the dentin was 5.93 MPa, and higher than that of control group (3.71 Mpa) (P < 0.05) whose dentin was treated with distilled water only. CONCLUSION: It was suggested that dentin inorganic material did play a proper role in dentin bond.

Acrylic Resins↗
PubMed1998

[Effect of the pH value of acid-salt pretreating solution system on dentin-bonding strength].

OBJECTIVE: In order to investigate the mechanism of dentin bond promoted by acid-salt pretreating solution system (APSS). METHODS: The tensile bonding strength (TBS) of 4-META/MMA-TBB resin to the dentin, which was treated by acid and retreated by APSS with different pH value, was tested. RESULTS: The TBS of dentin rose gradually from 10.41 MPa to 15.73 MPa with the decreasing of the pH value of APSS. The metallic salt solution containing acid or not, apparently affected the TBS of dentin. CONCLUSION: This study showed that the form of metallic ion in APSS correlated with the TBS of dentin.

Acrylic Resins↗
PubMed1998

[Histological and electron microscopic study of rotator cuff tear].

OBJECTIVE: To understand the changes of rotator cuff during tear and observe the pathologic and ultramicroscopic structure of rotator cuff. METHOD: Histological and ultra thin slides of samples of 36 cases of rotator cuff were made. RESULT: The degeneration of rotator cuff happened in synovium side, and then extended to the middle and deep sides of tendon. The deep side of cuff tendon could degenerate without synovium. The repair of tendon could be achieved with two types of healing. CONCLUSION: It would be difficult to achieve full repair when complete tear and deep side tear occurred to the rotator cuff.

Adult↗
PubMed1998

[Effect of heparinoid on the proliferation of rabbit vascular smooth muscle cells in vitro].

Proliferation of vascular smooth muscle cells(VSMCs) represents an important event in vascular lesion formation. In the present study, we investigated whether heparinoid abstracted from porcine duodenum inhibits the proliferation of rabbit aortic VSMCs in vitro, using the method of colorimetric MTT (tetrazolium). Our results showed that heparinoid at 1.6-0.05 mg.ml-1 significantly inhibits VSMCs proliferation induced by fetal calf serum(FCS, 10%), basic fibroblast growth factor(bFGF, 50 ng.ml-1) or interleukin-1(IL-1, 50 u.ml-1). In inducing with bFGF, the inhibitive effect of heparinoid was more potent than that of heparin, while in inducing with FCS or IL-1, the inhibitive effect of heparin was more potent than that of heparinoid. Preincubation with heparinoid at 0.2-0.05 mg.ml-1, the vascular smooth muscle cell proliferation induced by FCS was also inhibited. Our results imply that heparinoid may be useful to protect the atherosclerosis and angioplasty restenosis.

Animals↗
PubMed1998

[Sulfation of polysaccharides isolated from Indocalamus tesselatus and their anticytopathic effect on human immunodeficiency virus type I].

For preparation of sulfated polysaccharides isolated from bamboo leaves (Indocalamus tesselatus) with chlorosulfonic acid-pyridine, the experimental conditions as the molar ratio of reactants and temperature and time of reaction were discussed. A homogeneous sulfation method with good yield of more than 80% was obtained and the sufur content was found to be 21.9%. Conformation change in sulfated polysaccharide with changes of intrinsic viscosity, polarimetery and CD spectra were found to be related to the negative charge. The polysaccharide sulfates were shown to have better activity to inhibit cytopathic effect of human immunodeficiency virus(HIV) infection than native polysaccharides. The effective concentration was 10 micrograms.ml-1 while the cytotoxic concentration was 2.5 mg.ml-1.

Antiviral Agents↗
PubMed1998

[A preliminary report of the effect of levodopa and carbidopa for childhood amblyopia].

PURPOSE: To explore the short-term effect of levodopa and carbidopa in 36 children (4.5-14 years) with refractory amblyopia. METHODS: 36 cases of incurable childhood amblyopia treated with occlussion with visual acuity stably for 6 months were retreated by levodopa and carbidopa 1.5 mg/kg, 0.38 mg/kg respectively for 3 months. Visual acuity, fusional and stereoscopic function, retinal light sensitivity and scotomas were observed at 1 and 3 months after tablet taken. Medicine side effects were observed. RESULTS: At 3 months, the visual acuity of 88.89% eyes were improved(average 2.27 +/- 1.26 line), fusional and stereoscopic function were restored in 10 and 6 cases respectively. Retinal light sensitivity significantly increased, scotomas disappeared in 19 eyes and contracted in 6 eyes. The basic cure rate was 42.86% Less side effect were found. CONCLUSION: Average dose levels(1.5/0.38 mg/kg) of levodopa and carbidopa were an effective and secuity method to improve visual function of refractory childhood amblyopia.

Adolescent↗
PubMed1998

[Application of simple OMA system for rapid spectrochemical quantitative analysis to steel sample composition].

In this paper, the experimental method and characteristic of a simple optical multichannel analyzer (OMA) system used for rapid spectrochemical quantitative analysis was introduced. Mangangese and chromium contents in different steel samples were measured. The reliability of experimental results was discussed according to the mathematical statistics theory. Analytical results were compared with those of chemical and ICP analysis.

English Abstract↗
PubMed1998

Insulin-like growth factor binding protein-5 expression by human trabecular meshwork.

PURPOSE: The authors found transcript expression for insulin-like growth factor binding protein-5 (IGFBP-5) while screening for uniquely expressed trabecular meshwork (TM) mRNAs. Because the insulin-like growth factor (IGF) autocrine-paracrine system may provide an important signaling mechanism between TM cells and the outflow pathway, the expression of IGFBP-5 and IGF-I receptor in the TM was characterized. METHODS: Poly(A+) RNA was isolated from cell cultures of human TM, ciliary body, retinal pigment epithelium, and skin fibroblasts and subjected to reverse transcription-polymerase chain reaction (RT-PCR) differential display analysis. A unique 980-bp band present in the TM was cloned and sequenced. Additional PCR and Northern analyses were used to define trabecular IGFBP-5 expression. Western immunoblots and confocal immunohistochemistry were used to evaluate the protein expression patterns of IGFBP-5 and the IGF-I receptor. IGF-I and IGF-II were added to trabecular cells in culture, and matrix metalloproteinase production was evaluated. RESULTS: A unique differential display band was identified in the TM. Sequencing of this band identified it as the 3'-untranslated region of IGFBP-5. RT-PCR, using a variety of specific primers for IGFBP-5, Northern analysis, Western immunoblots, and immunohistochemical analysis, confirmed that IGFBP-5 was expressed in the TM. However, IGFBP-5 was also present at low levels in the ciliary body and skin fibroblasts by Northern and Western analysis, in contrast with the differential display findings. In addition, the IGF-I receptor was expressed by the TM and showed cell-surface staining by immunohistochemistry. Trabecular IGFBP-5 was distributed throughout the meshwork in the extracellular matrix and the cells with more staining in the juxtacanalicular region than in the uveal meshwork. IGF-I, but not IGF-II, modestly increased trabecular stromelysin and gelatinase B but not collagenase, gelatinase A, or tissue inhibitor of metalloproteinases 1 or 2. CONCLUSIONS: IGFBP-5 and IGF-I receptor were expressed at significant levels by TM cells and may serve an important role in trabecular function.

Blotting, Northern↗
PubMed1997

TWEAK, a new secreted ligand in the tumor necrosis factor family that weakly induces apoptosis.

The members of the tumor necrosis factor (TNF) family play pivotal roles in the regulation of the immune system. Here we describe a new ligand in this family, designated TWEAK. The mouse and human versions of this protein are unusually conserved with 93% amino acid identity in the receptor binding domain. The protein was efficiently secreted from cells indicating that, like TNF, TWEAK may have the long range effects of a secreted cytokine. TWEAK transcripts were abundant and found in many tissues, suggesting that TWEAK and TRAIL belong to a new group of widely expressed ligands. Like many members of the TNF family, TWEAK was able to induce interleukin-8 synthesis in a number of cell lines. The human adenocarcinoma cell line, HT29, underwent apoptosis in the presence of both TWEAK and interferon-gamma. Thus, TWEAK resembles many other TNF ligands in the capacity to induce cell death; however, the fact that TWEAK-sensitive cells are relatively rare suggests that TWEAK along with lymphotoxins alpha/beta and possibly CD30L trigger death via a weaker, nondeath domain-dependent mechanism.

Adenocarcinoma↗
PubMed1997

Prolonged discordant cardiac xenograft survival in newborn recipients.

BACKGROUND: We previously demonstrated very low levels of xenoreactive natural antibodies in newborns, suggesting the possibility of prolongation of xenograft survival in newborn recipients. We used a pig-to-newborn goat heterotopic cardiac xenograft model to examine our hypothesis that hyperacute rejection would be absent in newborn recipients and that both humoral and cellular rejection would participate in the late phase of discordant xenograft rejection. METHODS AND RESULTS: The serum of newborn goats was found to have very low titers of natural anti-pig antibodies. Newborn pig hearts were transplanted heterotopically into the neck of four unmanipulated newborn goats: none of these xenografts underwent hyperacute rejection. Dilation of the xenografts and decreased contractility were observed 4 to 6 days after transplantation, and the xenografts eventually ceased functioning between 6 and 8 days after transplantation. Blood samples collected after transplantation demonstrated a dramatic increase in anti-pig xenoantibody titers and correlated with histological studies demonstrating features consistent with delayed humoral rejection, including reactive vascular endothelial and perivascular stromal cells, marked capillary congestion, and interstitial hemorrhages. Scant to diffuse perivascular and interstitial infiltration of activated lymphoid cells occurred. CONCLUSIONS: Our study demonstrates that hyperacute rejection does not occur, allowing limited prolongation of xenograft survival in a pig-to-newborn goat cardiac xenograft model. We propose that this is attributable, at least in part, to the very low titers of natural antibodies in newborn recipients. Delayed xenograft rejection, however, remains an important problem in these newborn recipients. This delayed xenograft rejection is likely the result of both humoral and cellular rejection mechanisms.

Animals↗
PubMed1997

Distinct roles for B7-1 and B7-2 determinants during priming of effector CD8+ Tc1 and regulatory CD4+ Th2 cells for contact hypersensitivity.

Contact hypersensitivity (CHS) is a CD8+ T cell-mediated response to hapten sensitization and challenge of the epidermis. Both the IFN-gamma-producing effector CD8+ T cells and the IL-4/IL-10-producing CD4+ T (Th2) cells that restrict the magnitude and duration of the response are primed by hapten-presenting Langerhans cells (hpLC). hpLC isolated from hapten-sensitized animals expressed high levels of B7-2 and lower levels of B7-1, suggesting the availability of each molecule to provide costimulation during CD8+ and CD4+ T cell priming for CHS. Anti-B7-2 Ab given during hapten sensitization inhibited effector CD8+ and regulatory CD4+ T cell development and the magnitude of the CHS response. Cytokine production by CD8+ and CD4+ T cells was reduced in anti-B7-2 Ab-treated animals, indicating that costimulation for T cell development was not compensated by hpLC-expressed B7-1. Anti-B7-1 Ab inhibited CHS and increased the number of Th2 cells primed during hapten sensitization without inhibiting development of the IFN-gamma-producing CD8+ T cells. Depletion of CD4+ T cells, however, abrogated the inhibitory effect of anti-B7-1 Ab on the CHS response, indicating the amplified Th2 response mediated this inhibition. These results indicate a requirement for B7-2 costimulation by effector CD8+ and regulatory CD4+ T cells during priming for CHS. The ability of anti-B7-1 Abs to amplify the regulatory CD4+ Th2 component and inhibit CHS suggests a strategy to inhibit unwanted CD8+ T cell-mediated immune responses to Ags in the skin.

Animals↗
PubMed1997

The selection of ELISA cut-off points for testing antibody to Newcastle disease by two-graph receiver operating characteristic (TG-ROC) analysis.

Two hundred and sixty field serum samples were tested for Newcastle disease (ND) antibodies using a commercial enzyme-linked immunosorbent assay (ELISA) and the haemagglutination inhibition test (HI). The HI test was regarded as the reference method. Reciprocal titres of 16 and above were considered positive. In this study the two-graph receiver operating characteristic (TG-ROC) analysis was used as a tool for selecting cut-off points. Sensitivity, specificity, efficiency and Youden's index were used as indices of test accuracy. The positive and negative predictive values of the ELISA results were analysed for various prevalence rates.

Animals↗