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Biomedical subjects

W Xu

Publications and source records attributed to W Xu.

At least 289 records · Page 16Linked to original sources
PubMed1999

[In vitro adherence of bacteria to intraocular lenses of different materials].

OBJECTIVE: To compare the in vitro adherence of different bacteria onto the surface of various intraocular lenses (IOLs). METHOD: Electron microscopic and bacterial culture quantitative methods were used to study the adherence of Staphylococcus (S) epidermidis, Staphylococcus aureus and Pseudomonas (P) aeruginosa onto the surface of PMMA and other three foldable IOL materials (HEMA, ACRY, SI). RESULTS: S. Epidermidis: HEMA < ACRY < SI < PMMA; S. aureus: HEMA was the least and PMMA was the most, no significant difference between ACRY and SI IOLs; P. aeruginosa: HEMA was the least while no significant difference among PMMA, SI and ACRY IOLs (P > 0.05). CONCLUSION: The foldable IOLs have the potent ability to reduce the infectious endophthalmitis after surgery of extraction of cataract with IOL implantation.

Acrylic Resins↗
PubMed1999

[Effect of bFGF, IGF-I and their synergy on the mitogenesis of bovine lens epithelial cells].

OBJECTIVE: To assess the effect of basic fibroblast growth factor (bFGF), insulin like growth factor-I (IGF-I) and their synergy on the mitosis of bovine lens epithelial cells (BLECs). METHODS: BLECs were cultured in vitro. The fourth passage cells were inoculated into 24 well tissue culture plates, treated with different concentrations of bFGF, IGF-I, and bFGF + 20 microg/L IGF-I for 20 hours, (3)H-thymidine was added for 16 hours, then the radioactivity was determined by liquid scintillation counting. RESULTS: Either bFGF (1 - 100 microg/L) or IGF-I (20 - 100 microg/L) increases mitosis of BLEC significantly, and 20 microg/L IGF-I may increase bFGF induced mitogenesis. CONCLUSION: Growth factor and their synergic effect may play an important role in lens epithelial cell proliferation.

Animals↗
PubMed1999

[Histological grading in ductal carcinoma in situ of the breast].

OBJECTIVE: To study the significance of histological grading as a prognostic factor in ductal carcinoma in situ of the breast. METHODS: According to Van Nuy's classification, 32 cases of ductal carcinoma in situ (DCIS) of the breast were divided into three grades. RESULTS: Low grade (well differentiated, low grade DCIS) 12 patients (37.5%); Intermediate grade, 9 patients (28.1%); High grade (poorly differentiated DCIS) 11 patients (34.4%). Among the high grade DCIS, the histological subtypes were comedo (9 patients), micto papillary (1 patient) and solid (1 patient). The positive expression of c-erbB-2, p53 and MIB-1 in high grade DCIS was higher than that in intermediate and low grade DCIS. The difference between high grade and low grade DCIS was significant (P < 0.05). The expression of ER in high grade DCIS was lower than that in intermediate and low grade DCIS. CONCLUSIONS: Histological grading of breast ductal carcinoma in situ may be a good prognostic factor.

Adult↗
PubMed1999

[Studies on chemical constituents and pharmacological effects of the stem of Cynomorium songaricum Rupr].

OBJECTIVE: In order to exploit the medicinal resources and provide a scientific evidence for the clinical use and quality of Cynomorium songaricum control, the chemical constituents and pharmacological effects of the stem of the plant were studied preliminarily. METHOD: The chemical constituents were studied by spectral analysis and chemical method. The pharmacological effects were studied by an experiment on the defecation and deficiency of kidney function. RESULT AND CONCLUSION: Seven compounds were isolated from the stem of C. songaricum and identified as beta-sitosterol(I), palmitic acid (II), ursloic acid (III), daucosterol (IV), (-)-catechin (VI), naringenin-4'-O-pyranogluoside (VII) and succinicyacid (XII). Compounds VI and XII were isolated from this species for the first time. The pharmacological results show that the different extracts facilitate catharsis and replenish the deficiency of kidney yang.

Animals↗
PubMed1999

[Analysis of rice leaf proteins induced by Magnaporthe grisae with capillary zone electrophoresis].

Intercellular and intracellular proteins which were extracted from rice seedling leaves induced by Magnaporthe grisae, as well as those of control, were analysed by capillary zone electrophoresis. Intercellular proteins were extracted with sterilized water, while intracellular proteins were extracted with acidic protein extraction buffer. Protein adsorption to capillary wall was suppressed by using linear polyacrylamide coated capillary (75 microns x 57 cm) instead of uncoated capillary. Separations were performed at 25 degrees C with a positive voltage of 20 kV. Samples were injected into the capillary by applying pressure (3.0 kPa) for 5 s. The running buffer consisted of 50 mmol/L phosphoric acid (pH 2.0), and detection was achieved at 200 nm with a diode array detector. Being compared with a control, a new kind of protein induced by Magnaporthe grisae was identified in rice leaf intracellular proteins with Grubbs method which is used to test outliers in mathematical statistics.

English Abstract↗
PubMed1999

[Preliminary studies on microwave irradiation ELISA for diagnosis of Schistosomiasis japonica].

AIM: To explore a fast and highly efficient method for the diagnosis of schistosomiasis japonica. METHODS: Using microwave irradiation ELISA (MWI-ELISA) and fast-ELISA to detect specific antibodies in sera from 118 cases with schistosomiasis japonica, 61 healthy individuals and 12 paragonimiasis cases. RESULTS: The positive rates of schistosomiasis cases were 88.1% (104/118) by MWI-ELISA and 91.5% (108/118) by fast-ELISA, respectively (chi 2 = 0.74, P > 0.05). The false positive reaction of healthy individuals was found in 2 cases(3.3%) by MWI-ELISA and 1 case (1.6%) by fast-ELISA, respectively (chi 2 = 0.34, P > 0.05). No false positive reaction was found in paragonimiasis cases. CONCLUSION: The sensitivity and specificity of the two tests were similar, however, MWI-ELISA was faster than fast-ELISA.

Animals↗
PubMed1999

[Dexamethasone inhibits IL-5-induced eosinophil survival].

OBJECTIVE: To assess the effect of dexamethasone (Dex) on interleukine-5-induced survival of eosinophils (EOS) in vitro. METHODS: EOS were purified from guinea pigs by Percoll density gradient and incubated for 4 days in the presence of IL-5 with or without Dex. Cell viabilities were determined by staining cells with fluorescein diacetate and propidium iodide. RESULTS: In the absence of Dex, IL-5 enhanced EOS survival was inhibited in a dosedependent manner. Inhibition was time-dependent and required at least 2 days exposure of EOS to Dex. When EOS were incubated with varying concentrations of IL-5 and 1,000 nmol/l Dex, survival inhibition was reduced at higher concentration of IL-5, and completely abolished by IL-5 1,000 pg/ml. CONCLUSIONS: Dex acts directly on mature EOS to decrease their viabilities, implying the Dex may be important in the treatment of allergic and other inflammatory eosinophilic disorders.

Animals↗
PubMed1999

[Endoscopic CO2 laser arytenoidectomy in the treatment of bilateral vocal cord paralysis].

OBJECTIVE: To evaluate endoscopic CO2 laser arytenoidectomy(ECO2LA) for the treatment of bilateral vocal cord paralysis (BVCP). METHODS: Eight cases have been operated upon and observed for 6 to 40 months. Three of them were extralaryngeal approach artenoidectomy failures. All of them had tracheostomy before. The technique was to modification of Ossoff ECO2LA model. A small part of ventricular fold and posterior part of vocal cord was vaporized by laser. The mucoperichondrium overlying the arytenoid was reserved and sutured. After 3 months the opposite arytenoid was treated similarly. RESULTS: There were no aspiration and no granulation at the surgical site postoperatively. All cases kept satisfactory voice. Five of 8 patients were decannulated. Two patients still had laryngeal stridor during sleep and they had to plug the tracheotomy tube only on daytime. One patient had cannula retained for waiting operation on the opposite side. CONCLUSION: ECO2LA is currently a most reliable and efficient technique for treatment of patients with BVCP.

Adolescent↗
PubMed1999

[Spectroscopic study on the structure and orientation of 1-hydroxyl-5-dodecyloxy-naphthalene LB films].

Ultraviolet-visible (UV-Vis), infrared transmission reflection absorption (RA) and ATR spectra were used to study the mono-and multi-layer Langmuir-Blodgett (LB) films of C12H25ONaph (1,5)OH at various temperatures to investigate dependencies of the aggregation and phase transitions on the number of monolayers. The UV-vis spectra of the LB films revealed that C12H25ONaph (1,5)OH forms aggregates in the LB film. From the temperature dependence of UV-vis absorption spectra, it is clear that the aggregate was gradually converted to monomer with the temperature increased. A comparison of the infrared transmission and ATR spectra reveals that the hydrocarbon chains were tilted considerably in the LB film.

English Abstract↗
PubMed1998

Protein-protein interactions on weak-cation-exchange sorbent surfaces during chromatographic separations.

This paper examines the nature of chromatographic separations on a weak cation-exchange material in which immobilized protein coats 24% or less of the sorbent surface. It was found that columns on which proteins were immobilized still behaved as a cation-exchange chromatography sorbents, but their selectivity was different from the parent weak cation-exchange column. This was interpreted to mean that in addition to the normal electrostatic interactions expected in ion- exchange chromatography, protein analytes interact with immobilized protein on the sorbent surface. Anionic proteins were not adsorbed, indicating that immobilized proteins were acting synergistically with ionic stationary phase groups to enhance retention. It is concluded that these protein-protein interactions occur after proteins are captured by the primary interaction mechanism of the column, in this case, electrostatic interaction. Protein-protein interaction is a secondary, lateral process. These lateral interactions were observed between 4% and 24% surface saturation. The significance of this observation is that in preparative chromatography and the case of "fouled" columns, strongly adsorbed proteins could alter the elution characteristics of sample proteins being target for analysis or purification.

Cation Exchange Resins↗
PubMed1998

Palmitoylation of the rat mu opioid receptor.

We examined whether the mu opioid receptor was palmitoylated and attempted to determine sites of palmitoylation. Following metabolic labeling with [3H]palmitic acid and immunoaffinity purification of the mu opioid receptor, SDS-PAGE and fluorography revealed a broad labeled band with Mr of approximately 80 kDa in CHO cells stably expressing the rat mu receptor, but not in CHO cells transfected with the vector alone, indicating that the mu receptor is palmitoylated. Activation of the receptor with morphine did not affect the extent of palmitoylation. Hydroxylamine or dithiothreitol treatment removed most of the radioactivity, demonstrating that [3H]palmitic acid is incorporated into Cys residue(s) via thioester bond(s). Surprisingly, mutations of the only two Cys residues in the C-terminal domain did not reduce [3H]palmitic acid incorporation significantly. Thus, unlike many G-protein coupled receptors, the palmitoylation site(s) of the rat mu opioid receptor do(es) not reside in the C-terminal domain.

Amino Acid Sequence↗
PubMed1998

Congenital erythropoietic porphyria successfully treated by allogeneic bone marrow transplantation.

The long-term biochemical and clinical effectiveness of allogenic bone marrow transplantation (BMT) was shown in a severely affected, transfusion-dependent 18-month-old female with congenital erythropoietic porphyria (CEP), an autosomal recessive inborn error of heme biosynthesis resulting from mutations in the uroporphyrinogen III synthase (URO-synthase) gene. Three years post-BMT, the recipient had normal hemoglobin, markedly reduced urinary porphyrin excretion, and no cutaneous lesions with unlimited exposure to sunlight. The patient was homoallelic for a novel URO-synthase missense mutation, G188R, that expressed less than 5% of mean normal activity in Escherichia coli, consistent with her transfusion dependency. Because the clinical severity of CEP is highly variable, ranging from nonimmune hydrops fetalis to milder, later onset forms with only cutaneous lesions, the importance of genotyping newly diagnosed infants to select severely affected patients for BMT is emphasized. In addition, the long-term effectiveness of BMT in this patient provides the rationale for future hematopoietic stem cell gene therapy in severely affected patients with CEP.

Bone Marrow Transplantation↗
PubMed1998

Senescent BALB/c mice exhibit decreased expression of lambda5 surrogate light chains and reduced development within the pre-B cell compartment.

Although senescent BALB/c mice (approximately 2 years old) have reduced numbers of small pre-B cells, early pre-B cells (CD43+CD25+B220+) are present in comparable numbers within the bone marrow of both young (3-6-month-old) and senescent BALB/c mice. The transition of CD43+ pre-B cells to the CD43- pre-B cell compartments is dependent on proliferation and clonal maturation dictated by the pre-B cell receptor (mu/lambda5/VpreB). In vivo, senescent CD43+B220+ pro-B/early pre-B cells demonstrated reduction of lambda5 mRNA, by RT-PCR analysis, and of both surface and cytoplasmic lambda5 protein. Decreased lambda5 protein expression was also seen among pro-B/pre-B cells derived from senescent bone marrow after stimulation in vitro with IL-7. We propose that diminished expression of the lambda5 surrogate light chain results in decreased pre-B cell receptor formation and contributes to reduced recruitment of nascent CD43+ pre-B cells into the CD43- large and small pre-B cell compartments.

Aging↗
PubMed1998

Assembly of a tailed bacterial virus and its genome release studied in three dimensions.

We present the first three-dimensional reconstruction of a prolate, tailed phage, and its empty prohead precursor by cryo-electron microscopy. The head-tail connector, the central component of the DNA packaging machine, is visualized for the first time in situ within the Bacillus subtilis dsDNA phage phi29. The connector, with 12- or 13-fold symmetry, appears to fit loosely into a pentameric vertex of the head, a symmetry mismatch that may be required to rotate the connector to package DNA. The prolate head of phi29 has 10 hexameric units in its cylindrical equatorial region, and 11 pentameric and 20 hexameric units comprise icosahedral end-caps with T=3 quasi-symmetry. Reconstruction of an emptied phage particle shows that the connector and neck/tail assembly undergo significant conformational changes upon ejection of DNA.

Bacillus Phages↗
PubMed1998

Molecular cloning of human ABPL, an actin-binding protein homologue.

Based on two partial cDNA sequences, a full-length cDNA sequence for an actin-binding like protein previously named ABPL has been isolated and characterized. ABPL is homologous to the human actin-binding proteins ABP-280 and ABP-278. The predicted sequence for ABPL is 2,705 amino acids in length with a calculated molecular mass of 289 kDa. It contains an amino terminal actin-binding domain followed by 24 tandem repeats of approximately 96 amino acids. Two hinge regions, Hinge I and Hinge II, were located prior to repeats 16 and 24, respectively. An isoform of ABPL lacking Hinge I, with a calculated molecular mass of 286 kDa, was also identified by the reverse transcriptase PCR (RT-PCR) method. A comparison with genomic sequences indicated the isoform resulted from alternative RNA splicing. ABPL has a unique insertion sequence of 82 amino acids in repeat 20 that was not present in the other two homologues and has a tissue distribution that was also different from the other two homologues.

Actins↗
PubMed1998

Predictors of differential response to clozapine and haloperidol. Veterans Affairs Cooperative Study Group on Clozapine in Refractory Schizophrenia.

BACKGROUND: We sought to identify baseline predictors of response to clozapine. METHODS: Data were from a 15-site randomized clinical trial comparing clozapine and haloperidol in hospitalized patients with refractory schizophrenia (n = 423). Three-month outcomes were analyzed with the full sample (n = 368 due to attrition). Because of crossovers, analyses of 12-month outcomes were conducted with crossovers excluded (n = 291). Clinical predictors included age, race, diagnosis (current substance abuse, paranoid subtype of schizophrenia, or depressive syndrome), severity of symptoms, quality of life, age at onset of schizophrenia, extrapyramidal symptoms, and VA compensation payment. Multiple regression analysis was used to examine the interaction of treatment condition and each of these variables in predicting outcomes for symptoms, quality of life, side effects, and days hospitalized. RESULTS: Patients with higher quality of life at baseline (p = .04) and higher symptoms (p = .02) had relatively smaller declines in hospital days at 6 months. In the 12-month sample patients with higher levels of symptoms had greater symptom reductions at 12 months (p = .03) and greater improvement in quality of life (p = .004). CONCLUSIONS: Although high levels of symptoms were associated with greater improvement on clozapine, these findings are not robust enough to suggest that any specific, clinically defined subgroup of refractory patients should be preferentially targeted for clozapine treatment.

Adult↗