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W Xu

Publications and source records attributed to W Xu.

At least 199 records · Page 11Linked to original sources
PubMed2000

Species-specific identification of human adenoviruses by a multiplex PCR assay.

A multiplex PCR assay was developed by using primers to the fiber gene that could differentiate human adenovirus (Ad) species A through F in a single amplification reaction. The assay correctly identified the species of all 49 recognized Ad prototype strains as well as 180 geographically and temporally diverse Ad field isolates. Ad serotype 6 (Ad6) (species C), Ad16 (species B), Ad31 (species A), and Ad40 and Ad41 (species F) could also be distinguished by amplicon size within each respective species. In comparison, a previously described Ad species-specific multiplex PCR assay that used primers to the Ad hexon gene gave equivocal results with several serotypes of species B, whereas our multiplex assay amplified all species B serotypes equally well. Our multiplex PCR assay will permit rapid, accurate, and cost-effective classification of Ad isolates.

Adenovirus Infections, Human↗
PubMed2000

Cloning and functional characterization of the early-lymphocyte-specific Pb99 gene.

The Pb99 gene is specifically expressed in pre-B cells and thymocytes and not in mature B and T cells or nonlymphoid tissues, implying that it may function in early lymphoid development. We have previously described the cloning of an incomplete cDNA for Pb99. Here we report the isolation of full-length cDNAs and genomic clones for the murine Pb99 gene and the mapping of its location to mouse chromosome 8. Sequence analyses of different Pb99 cDNA clones suggest that there may be at least three forms of the Pb99 protein generated by differential processing of the Pb99 transcript. The cDNA with the longest open reading frame encodes a putative protein that has seven hydrophobic domains similar to those of seven membrane-spanning proteins, such as the classical G protein-coupled receptors. To directly address the role of the Pb99 protein in lymphoid development, Pb99-deficient mice were generated by gene targeting, and lymphocyte development in these mice was analyzed.

Amino Acid Sequence↗
PubMed2000

Cyclic nucleotide-gated cation channels mediate sodium and calcium influx in rat colon.

We found mRNA for the three isoforms of the cyclic nucleotide-gated nonselective cation channel expressed in the mucosal layer of the rat intestine from the duodenum to the colon and in intestinal epithelial cell lines in culture. Because these channels are permeable to sodium and calcium and are stimulated by cGMP or cAMP, we measured 8-bromo-cGMP-stimulated sodium-mediated short-circuit current (I(sc)) in proximal and distal colon and unidirectional (45)Ca(2+) fluxes in proximal colon to determine whether these channels could mediate transepithelial sodium and calcium absorption across the colon. Sodium-mediated I(sc), stimulated by 8-bromo-cGMP, were inhibited by dichlorobenzamil and l-cis-diltiazem, blockers of cyclic nucleotide-gated cation channels, suggesting that these ion channels can mediate transepithelial sodium absorption. Sodium-mediated I(sc) and net transepithelial (45)Ca(2+) absorption were stimulated by heat-stable toxin from Escherichia coli that increases cGMP. Addition of l-cis-diltiazem inhibited the enhanced transepithelial absorption of both ions. These results suggest that cyclic nucleotide-gated cation channels simultaneously increase net sodium and calcium absorption in the colon of the rat.

Animals↗
PubMed2000

Probing the extracellular release site of the plasma membrane calcium pump.

The plasma membrane Ca(2+) pump is known to mediate Ca(2+)/H(+) exchange. Extracellular protons activated (45)Ca(2+) efflux from human red blood cells with a half-maximal inhibition constant of 2 nM when the intracellular pH was fixed. An increase in pH from 7.2 to 8.2 decreased the IC(50) for extracellular Ca(2+) from approximately 33 to approximately 6 mM. Changing the membrane potential by >54 mV had no effect on the IC(50) for extracellular Ca(2+). This argues against Ca(2+) release through a high-field access channel. Extracellular Ni(2+) inhibited Ca(2+) efflux with an IC(50) of 11 mM. Extracellular Cd(2+) inhibited with an IC(50) of 1. 5 mM, >10 times better than Ca(2+). The Cd(2+) IC(50) also decreased when the pH was raised from 7.1 to 8.2, consistent with Ca(2+), Cd(2+), and H(+) competing for the same site. The higher affinity for inhibition by Ni(2+) and Cd(2+) is consistent with a histidine or cysteine as part of the release site. The cysteine reagent 2-(trimethylammonium)ethyl methanethiosulfonate did not inhibit Ca(2+) efflux. Our results are consistent with the notion that the release site contains a histidine.

Binding Sites↗
PubMed2000

Finite element analysis of bone stress and strain around a distal osseointegrated implant for prosthetic limb attachment.

Direct skeletal attachment techniques have recently been identified as an alternative method for percutaneous attachment of prosthetic limbs. Osseointegrated implants for prosthetic attachments are subjected to a complex load condition. This finite element study investigates the effect of varying geometries of the implant on the stress and strain distribution in the area of the bone/implant interface. Simplified three-dimensional axisymmetric models of the femur and seven implants with different core diameters, external diameters, implant lengths and thread pitches were derived. The resulting stress and strain distributions were compared. The significance of each implant geometry was identified for improving implant design in the light of benefit to the bone/implant osseointegration and the bone remodelling of the femur.

Artificial Limbs↗
PubMed2000

Clinical and psychopharmacologic factors influencing family burden in refractory schizophrenia. The Department of Veterans Affairs Cooperative Study Group on Clozapine in Refractory Schizophrenia.

BACKGROUND: This study compares the effect of clozapine and haloperidol and identifies other factors related to family burden as experienced by relatives of patients with refractory schizophrenia (DSM-III-R). METHOD: Of 423 patients participating in a multisite randomized clinical trial, 221 identified a family member who was actively involved in their care and who agreed to complete a standardized measure of family burden at 6 weeks and 3, 6, 9, and 12 months after randomization, simultaneous with comprehensive patient assessments. RESULTS: Patient factors most consistently correlated with greater family burden were symptom severity, days living in the community (i.e., not in the hospital), and frequency of family contact. Among family members, clozapine was associated with significantly (p = .048) greater reduction in feelings of dissatisfaction related to providing support to the patient, but not in objective measures of support, amount of worry the patient engendered, or days of missed employment or household activity. Although clozapine reduces symptoms, thus lowering family burden, it also increases days living in the community, which tends to increase family burden, perhaps canceling out the benefit to families of reduced symptoms. CONCLUSION: Clozapine has a small but significant effect on the experience of families of patients. This is the first study to demonstrate that effective pharmacotherapy may be of some benefit to families as well as to patients.

Adult↗
PubMed2000

Medication continuation and compliance: a comparison of patients treated with clozapine and haloperidol.

BACKGROUND: This study compares medication continuation and regimen compliance with the atypical antipsychotic medication clozapine versus the conventional antipsychotic haloperidol. METHOD: Data from a 15-site double-blind, randomized clinical trial (N = 423) were used to compare patients with DSM-III-R schizophrenia assigned to clozapine or haloperidol in terms of duration of participation while taking the randomly assigned study drug (continuation) and the proportion of prescribed pills that were taken (compliance). Multiple regression analysis was used to determine the relationship of baseline characteristics and measures of clinical change to continuation for the entire sample and for patients assigned to each medication. RESULTS: Patients assigned to clozapine continued taking the study drug for a mean of 35.5 weeks as compared with only 27.2 among patients assigned to haloperidol (F = 4.45, df = 1,422; p = .0001). No differences were found between the groups in the proportion of prescribed pills that were returned at any timepoint. Among patients assigned to haloperidol, poorer continuation was associated with being older and greater continuation with receiving public support. Among patients on clozapine treatment, continuation was poorer among African American patients and greater among patients who showed reduced clinical symptoms and akathisia. Continuation with clozapine was greater even after adjusting for these factors. CONCLUSION: Continuation with medication is greater with clozapine than haloperidol and is partly explained by greater symptom improvement and reduced side effects. No differences were found in regimen compliance.

Adult↗
PubMed2000

Molecular mapping of QTLs conferring stay-green in grain sorghum (Sorghum bicolor L. Moench).

Drought resistance is of enormous importance in crop production. The identification of genetic factors involved in plant response to drought stress provides a strong foundation for improving drought tolerance. Stay-green is a drought resistance trait in sorghum (Sorghum bicolor L. Moench) that gives plants resistance to premature senescence under severe soil moisture stress during the post-flowering stage. The objective of this study was to map quantitative trait loci (QTLs) that control the stay-green and chlorophyll content in sorghum. By using a restriction fragment length polymorphism (RFLP) map, developed from a recombinant inbred line (RIL) population, we identified four stay-green QTLs, located on three linkage groups. The QTLs (Stg1 and Stg2) are on linkage group A, with the other two, Stg3 and Stg4, on linkage groups D and J, respectively. Two stay-green QTLs, Stg1 and Stg2, explaining 13-20% and 20-30% of the phenotypic variability, respectively, were consistently identified in all trials at different locations in two years. Three QTLs for chlorophyll content (Chl1, Chl2, and Chl3), explaining 25-30% of the phenotypic variability were also identified under post-flowering drought stress. All coincided with the three stay-green QTL regions (Stg1, Stg2, and Stg3) accounting for 46% of the phenotypic variation. The Stg1 and Stg2 regions also contain the genes for key photosynthetic enzymes, heat shock proteins, and an abscisic acid (ABA) responsive gene. Such spatial arrangement shows that linkage group A is important for drought- and heat-stress tolerance and yield production in sorghum. High-resolution mapping and cloning of the consistent stay-green QTLs may help to develop drought-resistant hybrids and to understand the mechanism of drought-induced senescence in plants.

Adaptation, Physiological↗
PubMed2000

[Endothelial dysfunction and injury of placental and umbilical vessels in pregnancy-induced hypertension is associated with tumor necrosis factor].

OBJECTIVE: To investigate the relation between endothelial dysfunction and injury of placental and umbilical vessels in pregnancy-induced hypertension (PIH) and tumor necrosis factor (TNF). METHODS: The concentration of plasma TNF, endothelin (ET) and nitric oxide (NO) in PIH women and normal pregnant women (control group) were measured. The ultrastructure of placenta and umbilical vein endothelial cells in PIH and normal pregnant women was observed. The ultrastructure of endothelial cells in culture with TNF (400 u/ml) was also observed. RESULTS: Maternal plasma TNF and ET levels in PIH patients were (2.27 +/- 0.42) micrograms/L and (73.31 +/- 9.98) ng/L, respectively, higher than that in the control [TNF and ET lever were (1.72 +/- 0.25) micrograms/L and (2.32 +/- 10.44) ng/L, respectively]. NO level in PIH patients was (104.93 +/- 20.54) mumol/L, lower than that in the control [NO lever was (138.25 +/- 22.16) mumol/L] (P < 0.05). The ultrastructure of placental and umbilical vascular endothelial cells in moderate and severe PIH patients revealed injured. Similar injury was observed in endothelial cells in culture with TNF. CONCLUSIONS: TNF can induce the endothelial cells dysfunction and injury. It may be involved the pathogenesis of PIH.

Adult↗
PubMed2000

The potential role of PDGF, IGF-1, TGF-beta expression in idiopathic pulmonary fibrosis.

OBJECTIVE: To identify the role of cytokines involved in the development of lung fibrosis in patients with idiopathic-pulmonary fibrosis (IPF). METHODS: Proteins and gene expression of platelet-derived growth factor (PDGF)-A and -B, insulin-like growth factor 1 (IGF-1), and transforming growth factor beta (TGF-beta) were measured in alveolar macrophages and open lung biopsies from patients with IPF using immunohistochemistry (IHC) and in situ hybridization (ISH). RESULTS: In specimens of bronchoalveolar lavage fluid (BALF), PDGF-A, PDGF-B, IGF-1, TGF-beta were localized in alveolar macrophages. Evaluation of open lung biopsies from patients with IPF showed that IGF-1 was prominently present in pulmonary vessel walls in fibrotic lesions. PDGF and TGF-beta proteins were localized to hyperplastic bronchio-alveolar epithelial cells, alveolar macrophages, fibroblasts, vascular smooth muscle and endothelial cells. Our in situ hybridization results were consistent with that of immunohistochemistry except that PDGF-A and TGF-beta mRNA transcripts were not detected in bronchoalveolar epithelial cells. CONCLUSION: These observations suggest that (1) alveolar macrophages play key roles not only in inflammation but also in the fibrotic process by releasing PDGF, IGF-1 and TGF-beta; (2) IGF-1 could be responsible for angiogenesis in IPF; (3) PDGF, TGF-beta are associated with fibroplasia and the deposition of extracellular matrix, as well as vessel remodeling and epithelial cell repopularization.

Adult↗
PubMed2000

Molecular epidemiologic study of Mycoplasma genitalium infection in high risk populations of sexually transmitted diseases in China.

OBJECTIVE: To detect Mycoplasma genitalium (Mg) infection in high risk populations of sexually transmitted diseases (STDs) from several cities in China and to clarify the possible role of Mg in the pathogenesis of non-gonococcal urethritis. METHODS: Polymerase chain reaction (PCR) based on 2 pairs of primers, one for Mg-Pa (adhesion protein) and the other for 16S-rRNA (Mycoplasma genera) was used to detect Mg infection. Urogenital specimens of different high risk populations and urethritis patients, were collected from the Guangdong, Kunming, Shanghai, Nanjing, and Changzhou areas. RESULTS: The positive detection rate of Mg-DNA in high risk populations of STDs was significantly higher than that of the control group (chi 2 = 7.82, P < 0.01). The positive detection rates in Guangdong STD clinics and promiscuous persons from Kunming were higher than those from the Shanghai, Nanjing, and Changzhou areas (chi 2 = 8.54, P < 0.01 and chi 2 = 5.89, P < 0.05). Mg DNA could be detected in those patients without other relevant pathogens. Some patients were simultaneously infected with Mg and other microbes, such as Chlamydia trachomatis and/or Ureaplasma urelyticum. The positive Mg-DNA detection rate in patients with urethritis symptoms was higher than in patients without the symptoms (chi 2 = 11.68, P < 0.01). CONCLUSION: Mg infection exists in high risk populations of STDs in China, and the Mg infection rate is different among different high risk groups.

Adolescent↗
PubMed2000

[127 cases of pulmonary fungal infection].

OBJECTIVE: To find out the clinical features, therapeutic outcome, prognosis and the major predisposing diseases of pulmonary fungal infection(PFI). METHOD: 127 cases with PFI were retrospectively analyzed. RESULTS: Various predisposing diseases were found in 95% of total cases, among them, COPD, systemic lupus erythromatus(SLE), leukemia and chronic renal disease were main predisposing diseases. Primary pulmonary fungal infection was rare. All the clinical manifestations of PFI were not specific, reontgenographic features showed mainly bronchitis type(61%). Monilia (Candida) was ranked the first pathogen (79.5%). The mortality of PIF was high. Chronic renal and hematological diseases might be the risk factors for mortality (RR, relative rate, 5.14). CONCLUSIONS: PFI is an important cause of the secondary infection in many diseases. The clinical features of PFI is non-specific and the morbidity is rising. Clinicians should pay more attention to it.

Bronchitis↗
PubMed2000

[Influence of safflower injection on hemorheology of patients of chronic cor pulmonale during acute attack].

OBJECTIVE: To study the effect of safflower injection (SI) on hemorheology and fibrinolytic system in treating patients of chronic cor pulmonale during acute attack. METHODS: Sixty patients were divided into two groups, 30 in each group. Both groups were treated with conventional therapy including anti-inflammatory, relieving cough and reducing sputum, cardial, diuretic and continuous low-flow oxygen inhalation. For the SI group, additional two courses of SI injection was given intravenously for 10 days as one course with an interval of 5 days between courses. The clinical therapeutic effect in the two groups and effect of treatment on hemorheology and fibrinolytic function were observed. RESULTS: The total effective rate in the SI group was 86.7% and that in the control group was 63.3%, the difference between the two groups was significant (P < 0.05). After treatment, in the SI group, the high- and low-shear whole blood viscosity, plasma viscosity, erythrocyte agglutination index, hematocrit and fibrinogen lowered obviously, as compared with before treatment (P < 0.01 or P < 0.05), and the improvement in hemorrheologic property was better than that in the control group significantly (P < 0.05). The blood activities of anti-thrombin III, plasminogen and tectotype profibrinolytic activating factor were all higher than those in the control group (P < 0.05, P < 0.01). And SI showed more potent effect in improving anti-coagulation and fibrinolytic function of patients than that of the control (P < 0.05). CONCLUSION: SI is an effective drug for treatment of hypercoagulability status in acute stage of chronic cor pulmonale, and is worthy of clinical application.

Aged↗
PubMed2000

[Role of tumor necrosis factor -alpha in the pathogenesis of pregnancy-induced hypertension].

OBJECTIVE: To investigate the role of tumor necrosis factor-alpha (TNFalpha) in the pathogenesis of pregnancy induced hypertension (PIH) by damaging endothelial cells. METHODS: 41 patients with PIH and 17 healthy pregnant women were studied. The concentration of TNFalpha in maternal plasma was measured by sensitive radioimmunoassay. The morphology of endothelial cells of placental blood vessels was observed. Endothelial cells were incubated in the presence of TNFalpha (400 U/ml) and sera (30% vol/vol) from PIH women and normal pregnant women to observe their growth and shape. RESULTS: Maternal plasma TNFalpha level in PIH was 2.29 microgram/L +/- 0.51 microgram/L, higher than that in normal pregnancy (the latter was 1.73 microgram/L +/- 0.25 microgram/L, t = 5.60, P < 0.01). The endothelial cells of placental blood vessels in PIH revealed morphologic damages. Both sera of PIH women and TNFalpha were cytotoxic to endothelial cells in culture, including inhibition of the proliferation and morphologic changes of the cells. CONCLUSION: Damage of the endothelial cells of placental blood vessels is associated with the abnormal increase in the maternal blood TNFalpha. Sera of PIH women can damage the endothelial cells in culture and this effect is also associated with TNFalpha.

Adult↗
PubMed2000

[Germline LKB1 gene mutation screening in 4 Chinese Peutz-Jeghers syndrome pedigrees].

OBJECTIVE: To evaluate the frequency and nature of LKB1 gene germline mutations in 4 large Chinese Peutz-Jeghers syndrome pedigrees. METHODS: Four Chinese Peutz-Jeghers syndrome pedigrees were investigated. Two patients and 1 normal adult from each pedigree were selected, and genomic DNA from peripheral blood was extracted. The 9 exons of LKB1 gene were amplified by PCR. The products were tested by SSCP and abnormally shifted bands were sequenced. If there was no positive finding in any pedigree, the entire exons were sequenced. RESULTS: The same 842 C deletion of LKB1 gene frame-shift mutations was found in 2 pedigrees, which resulted in truncated protein. No exon variant was found in the left 2 pedigrees. CONCLUSIONS: LKB1 gene germline mutation is an important molecular pathogen of Peutz-Jeghers syndrome. 842 C deletion is a possible mutation hotspot and might be a common-ancestor mutation characteristic of Chinese.

AMP-Activated Protein Kinase Kinases↗
PubMed2000

[Dynamic changes in dermal cell cycles, contents of hydroproline and ratios of collagen type I/III in the burned wound].

OBJECTIVE: To study the dynamic changes in the dermal cell cycles contents of hydroproline and ratios of collagen type I/III in the burned wound. METHODS: The dermal cell cycles, contents of hydroproline, ratios of collagen type I/III and pathologic changes were dynamically observed in 48 deep partial burn rats (TBSA 10%), attempting to investigate the process of deep partial burn wound healing. RESULTS: The percentage of S-phase reached the highest point on PBD 10. On PBD21, it was still significantly higher than that of normal group. OHP increased gradually after burn, and peaked on PBD14. On PBD21, the level of OHP was still significantly higher than that of normal group. The ratios of collagen type I/III decreased gradually and significantly lower than those of the normal group after burn. The strips of WBC infiltrating into wound were observed on PBD3, 7 and 10. On PBD 14, a large number of regenerative epidermal cells crept over wound surface. CONCLUSIONS: The inflammation is obvious from PBD3 to PBD10. The proliferation of dermal cell and the synthesis, deposition of new collagen are predominant from PBD10 to PBD14, and the repair of dermis is not complete on PBD21. The proliferation and migration of epidermal cells are major activities from PBD14 to PBD21.

Animals↗
PubMed2000

[Combined phacoemulsification, foldable intraocular lens implantation and trabeculectomy for cataract patients with glaucoma].

OBJECTIVE: To evaluate the therapeutic effects and safety of the combined phacoemulsification, foldable intraocular lens implantation and trabeculectomy (triple procedure) and compare the outcomes of the operation with two different small incisions, conventional scleral flap and scleral tunnel flap. METHODS: Triple procedure was performed through a 3.5 mm incision by means of conventional scleral flap or scleral tunnel flap on 44 eyes of 42 patients with cataract and glaucoma. RESULTS: After follow-up for 3 -- 6 months, the mean intraocular pressure (IOP) was (14.33 +/- 3.68) mm Hg (1 mm Hg = 0.133 kPa) with a mean pressure reduction of 10.35 mm Hg from that before the operation (P < 0.001). Postoperatively, the visual acuities were >or= 0.5 in 33 eyes (75.0%) at 1 week and in 37 eyes (84.1%) during 3 - 6 months. The mean postoperative astigmatism was (1.29 +/- 0.93) D at 1 week and only 0.17D more than the mean preoperative one (P > 0.05). There was also no statistical difference between the mean preoperative astigmatism and postoperative astigmatism at 3 - 6 months, which was (1.12 +/- 0.73) D. The filtering blebs of type I and II (functional) by Kronfeld's classification presented in 79.5% of the eyes and type III (non-functional) in 20.5% of the eyes. There were no statistical differences for the postoperative outcomes of IOP, visual acuity, astigmatism and filtering bleb between two different procedure groups (P > 0.05). CONCLUSIONS: The triple procedure is an effective, quick, repeatable and safe procedure for cataract patients with glaucoma. There are no differences at the surgical outcomes of two different incisions by means of the conventional scleral flap vs scleral tunnel flap.

Adult↗