Biomedical subjects

W Wei

Publications and source records attributed to W Wei.

At least 37 records · Page 2Linked to original sources

PubMed2005

Concentration and detection of SARS coronavirus in sewage from Xiao Tang Shan Hospital and the 309th Hospital of the Chinese People's Liberation Army.

A worldwide outbreak of severe acute respiratory syndrome (SARS) had been reported. Over 8439 SARS cases and 812 SARS-related deaths were reported to the World Health Organization from 32 countries around the world up to 5 July 2003. The mechanism of transmission of SARS-CoV has been limited only to close contacts with patients. Attention was focused on possible transmission by the sewage system because laboratory studies showed that patients excreted coronavirus RNA in their stools in Amoy Gardens in Hong Kong. To explore whether the stool of SARS patients or the sewage containing the stool of patients would transmit SARS-CoV or not, we used a style of electropositive filter media particle to concentrate the SARS-CoV from the sewage of two hospitals receiving SARS patients in Beijing, as well as cell culture, semi-nested RT-PCR and sequencing of genes to detect and identify the viruses from sewage. There was no live SARS-CoV detected in the sewage in these assays. The nucleic acid of SARS-CoV was found in the sewage before disinfection from both hospitals by PCR. After disinfection, SARS-CoV RNA could be detected from some samples from the 309th Hospital of the Chinese People's Liberation Army, but not from Xiao Tang Shan Hospital after disinfection. In this study, we found that the virus can survive for 14 days in sewage at 4 degrees C, 2 days at 20 degrees C, and its RNA can be detected for 8 days though the virus had been inactivated. In conclusion, this study demonstrates that the RNA of SARS-CoV could be detected from the concentrates of sewage of both hospitals receiving SARS patients before disinfection and occasionally after disinfection though there was no live SARS-CoV; thus much attention should be paid to the treatment of stools of patients and the sewage of hospitals receiving SARS patients.

Bacteriophages↗

PubMed2004

Functional coupling, desensitization and internalization of virally expressed mu opioid receptors in cultured dorsal root ganglion neurons from mu opioid receptor knockout mice.

Although mu opioid receptors desensitize in various cell lines in vitro, the relationship of this change in signaling efficacy to the development of tolerance in vivo remains uncertain. It is clear that a system is needed in which functional mu opioid receptor expression is obtained in appropriate neurons so that desensitization can be measured, manipulated, and mutated receptors expressed in this environment. We have developed a recombinant system in which expression of a flag-tagged mu opioid receptor is returned to dorsal root ganglia neurons from mu opioid receptor knockout mice in vitro. Flow cytometry analysis showed that adenoviral-mediated expression of the amino-terminal flag-tagged mu opioid receptor in neurons resulted in approximately 1.3x10(6) receptors/cell. Many mu opioid receptor cell lines express a similar density of receptors but this is approximately 7x greater than the number of endogenous receptors expressed by matched wild-type neurons. Inhibition of the high voltage-activated calcium currents in dorsal root ganglia neurons by the mu agonist, D-Ala(2), N-MePhe(4), Gly(5)-ol-enkephalin (DAMGO), was not different between the endogenous and flag-tagged receptor at several concentrations of DAMGO used. Both receptors desensitized equally over the first 6 h of DAMGO pre-incubation, but after 24 h the response of the endogenous receptor to DAMGO had desensitized further than the flag- tagged receptor (71+/-3 vs 29+/-7% respectively; P<0.002), indicating less desensitization in neurons expressing a higher density of receptor. Using flow cytometry to quantify the percentage of receptors remaining on the neuronal cell surface, the flag-tagged receptor internalized by 17+/-1% after 20 min and 55+/-2% after 24 h of DAMGO. These data indicate that this return of function model in neurons recapitulates many of the characteristics of endogenous mu opioid receptor function previously identified in non-neuronal cell lines.

Animals↗

PubMed2004

Graves' hyperthyroidism and thyroiditis in HLA-DRB1*0301 (DR3) transgenic mice after immunization with thyrotropin receptor DNA.

Familial and twin studies in Caucasians have established that the MHC class II allele HLA-DRB1*0301 (DR3) is a strong susceptibility gene in Graves' hyperthyroid disease (GD). To determine if a DR3 transgene could help establish an animal model for GD, we expressed DR3 molecules in class II-knockout NOD mice (H2Ag7-). DR3+g7- mice were given cardiotoxin prior to immunization on weeks 0, 3 and 6 with plasmid DNA encoding human thyrotropin receptor (TSHR). Two groups of mice were also coimmunized with plasmid DNA for IL-4 or GM-CSF. Serial bleeds on weeks 8, 11 and 14 showed that approximately 20% of mice produced thyroid-stimulating antibodies (Abs), and approximately 25% had elevated T4 levels. In particular, a subset displayed both signs of hyperthyroidism, resulting in approximately 30% with some aspect of GD syndrome. Additional mice had thyroid-stimulating blocking Abs and/or TSH-binding inhibitory immunoglobulins, while most mice showed strong labelling of TSHR+ cells by flow cytometry. Interestingly, lymphocytic infiltration with thyroid damage and Abs to mouse thyroglobulin were also noted. Vector controls were uniformly negative. Thus, DR3 transgenic mice can serve as a model for GD, similar to our earlier reports that this allele is permissive for the Hashimoto's thyroiditis model induced with human thyroglobulin.

Animals↗

PubMed2004

Isolation of salt-sensitive mutants from Sinorhizobium meliloti and characterization of genes involved in salt tolerance.

AIMS: The purpose of our research is to isolate salt-sensitive mutants and to study the genes involved in salt tolerance of the salt-tolerant bacterium Sinorhizobium meliloti 042BM. METHODS: Wild type S. meliloti 042BM bacteria are able to grow at a NaCl concentration of 0.6 mol l(-1). A transposon Tn5-1063a mutagenesis library of S. meliloti 042BM was constructed and eight salt-sensitive mutants were isolated, which were unable to growth on FY plates containing 0.4 mol l(-1) NaCl. SIGNIFICANCE: Our interest is to provide information about the mechanism of salt tolerance in bacteria by studying the genes involved in salt tolerance. Here, seven different genes were identified. These genes include omp10 encoding a cell outer membrane protein, relA encoding (p)ppGpp synthetase, greA encoding a transcription cleavage factor, nuoL encoding NADH dehydrogenase I chain L transmembrane protein, a putative nuclease/helicase gene and two unknown genes. Based on these findings, we suggest that the regulation of salt tolerance of S. meliloti 042BM is complex and on several levels.

Bacterial Proteins↗

PubMed2004

The use of pulsed dye laser for the prevention and treatment of hypertrophic scars in chinese persons.

BACKGROUND: Pulse dye laser has been used with variable degrees of success in the treatment of hypertrophic scars, and although earlier reports suggested a significant degree of improvement, more recent studies have raised concern about its effectiveness. Furthermore, most previous studies examined its use in patients with light skin types, and the use of pulse dye laser in dark-skinned patients for the treatment of hypertrophic scars is not well established. OBJECTIVE: The objective was to assess the role of pulsed dye laser therapy in the treatment and prevention of hypertrophic scars in Chinese persons. METHODS: Twenty-nine patients (35 scars) who had scars for less than 6 months were recruited into the prevention group, and 27 patients (36 scars) who had scars for more than 6 months were recruited into the treatment arm of the study. Each received pulse dye laser treatment (585 nm, 1.5-msec pulse duration, 5-mm spot size, 7-8 J/cm(2)) for three to six treatments at 8-week intervals. Half of the scar was treated with the laser and the other half was used as a control. All patients were assessed for subjective improvement with the use of a structured questionnaire and objectively with ultrasonography for thickness and a cutometer for viscoelasticity. Scars were marked on every patient and mapped with a translucent paper at the first appointment to ensure the consistency of location. At the end of the study, 15 patients from the prevention group (15 scars) and 23 patients from the treatment group (34 scars) agreed to return for spectrophotometer assessment. RESULTS: Fifty-four percent of patients in the prevention group and 66% of patients in the treatment group considered their scars to be better or much better. For both groups of patients, there was significant improvement in term of pruritics after laser treatment. For objective assessment, although scar thickness reduced significantly compared to baseline in the treatment group, such change was not significant when changes in the control side were taken into consideration. There was insignificant change in viscoelasticity. Spectrophometer assessment indicated a significant degree of lightening in the treatment group. CONCLUSION: Our study indicated that although there was significant symptomatic improvement, there was an insignificant degree of objective improvement in terms of scar thickness and viscoelasticity in the prevention group compared to the control group. Our findings are in line with several previous controlled studies and contradict the results of several others. Such differences can be due to differences in assessment methodology, laser settings, skin type, and scar location. Suprapurpuric pulsed dye laser should not be considered as the standard of practice for the treatment and prevention of hypertrophic surgical scars especially in the chest in Asians patients.

Adolescent↗

PubMed2003

Polyunsaturated hydrocarbons in the hemolymph: biosynthetic precursors of epoxy pheromones of geometrid and arctiid moths.

Female moths of many species in Geometridae, Arctiidae and some other macrolepidopteran families produce epoxy pheromones, which are probably derived from polyunsaturated hydrocarbons. In order to understand a biosynthetic site, hemolymph from both sexes of two geometrid species, Ascotis selenaria cretacea and Hemerophila artilineata, and one arctiid species, Spilosoma imparilis, was shaken with n-hexane and the solvent extracts were analyzed by GC-MS. Each extract of the female hemolymph sex-specifically included polyunsaturated hydrocarbons corresponding to the pheromonal epoxy components in addition to many saturated hydrocarbons, but no epoxy compounds were detected in it. Based on this analysis, deuterated polyunsaturated hydrocarbons were injected into the abdomens of two geometrid females, and the labeled epoxy components were successfully yielded from the pheromone glands. This result indicated that the polyunsaturated hydrocarbons occurring in the female hemolymph were direct pheromone precursors, which might be produced outside the pheromone gland, probably in oenocytes associated with abdominal epidermal cells or in the fat body, and transported to the pheromone gland via the hemolymph for their epoxydation and emission into the atmosphere.

Animals↗

PubMed2002

Effects of ionization in single-bubble sonoluminescence.

We studied the effects of ionization in a sonoluminescing (SL) bubble within the hydrodynamic framework. The thermodynamic variables and the degrees of ionization inside the bubble throughout an oscillation cycle are obtained by solving the hydrodynamic equations assuming spherical symmetry. Several models are used to compute the emitted radiation, which are then compared with experimental data. Numerical results show that shock waves are absent in the stable SL regime, and compressional waves are already strong enough to produce moderate temperature and ionization. The degrees of ionization at the bubble center are found to be within 7% to 30%, and Ar+ is the only dominant ion. Moreover, an opacity-corrected blackbody radiation model gives the peak power, pulse widths, and spectra that agree very well with the experimental data.

Journal Article↗

PubMed2002

The protective effects of melatonin from oxidative damage induced by amyloid beta-peptide 25-35 in middle-aged rats.

This work investigated the ability of melatonin to prevent oxidative damage in brain tissue induced by injection of beta-amyloid peptide 25-35 (Abeta25-35) in middle-aged rats. The Morris water maze was used to evaluate the cognitive function of the rats. Thiobarbituric acid-reactive substances and antioxidative enzymes (superoxide dismutase and glutathione peroxidase) activities were measured. It was found that injection of (Abeta25-35) (20 microg) into the rat hippocampus caused an increase in the latency (the time to find the platform), the total swimming distance to the platform, and the starting angles in (Abeta25-35)-treated rats. Furthermore, a significant rise in lipid peroxidation and decrease in antioxidative enzyme activities in brain tissue were found. Melatonin (0.1, 1, and 10 mg/kg, i.g. x 10 days) improved the spatial resolution of amnesic rats in the Morris water maze test. Meanwhile, melatonin antagonized the lipid peroxidation in both the mitochondria (P < 0.01) at the doses of 0.1, 1.0, and 10 mg/kg and in the cytoplasm at the doses of 0.1 and 1.0 mg/kg. Also in the amnesic rats, melatonin (0.1, 1.0, and 10 mg/kg. i.g. x 10 days) stimulated the antioxidative enzyme activities. The results show that melatonin effectively reduced lipid peroxidation and enhanced the antioxidative enzyme activities in Abeta(25-35)-treated rats, which may contribute to the improvement of rats' learning and memory impaired by Abeta(25-35).

Age Factors↗

PubMed2002

Two novel strains of Wolbachia coexisting in both species of mulberry leafhoppers.

Wolbachia is an intracellular symbiont that causes reproductive disorders in many insects. Its presence in the leafhoppers Hishimonoides sellatiformis and Hishimonus sellatus, vectors of mulberry dwarf-Phytoplasma, was confirmed by the PCR analysis of 16S rDNA, ftsZ and wsp. Sequencing of cloned PCR products revealed that two Wolbachia strains coexist in both leafhoppers. The phylogenetic analysis of wsp revealed that these strains belong in novel positions in the B-group of Wolbachia. These strains were detected by PCR and/or PCR-RFLP in all of the tested non-genital organs including salivary glands, as well as in the tested genital organs of Hishimonoides sellatiformis. In addition, Wolbachia-like organisms were observed by electron microscopy in all PCR-positive organs. We discuss the possible horizontal transmission of Wolbachia via mulberry trees.

Animals↗

PubMed2001

Monitoring for adsorption of human serum albumin and bovine serum albumin onto bare and polystyrene-modified silver electrodes by quartz crystal impedance analysis.

The adsorption of human serum albumin (HSA) and bovine serum albumin (BSA) from PBS (pH 7.4) onto bare and polystyrene (PS)-modified silver electrodes was in situ monitored using quartz crystal impedance analysis. The adsorption characteristics of HSA and BSA were discussed by analyzing piezoelectric parameter simultaneous responses. Experimental results indicated that for both HSA and BSA, the amount adsorbed on bare silver was more than that on PS-modified surface. The BSA amount adsorbed on the two surfaces was more than that of adsorbed HSA. A kinetic model was developed to describe the adsorption process and fitted to the experimental data of frequency shift. It was shown that HSA adsorption could be described by a kinetic equation involving two consecutive reactions. At lower concentration, BSA adsorption only involved the first reaction. At higher concentration, BSA adsorption on PS-modified surface involved two consecutive reactions. All fitted results were well in agreement with the corresponding experimental results. The regression values of reaction rate constants for the HSA and BSA adsorption were obtained. These data exhibited difference in adsorption kinetics under different conditions.

Adsorption↗

PubMed2001

Use of a quartz crystal impedance technique to monitor the degradation of chondroitin sulfate by hyaluronidase.

A new quartz crystal impedance hyaluronidase sensing technique, which is based on the changes in viscosity and density during the enzymatic hydrolysis of chondroitin sulfate (CS) by hyaluronidase (HAse), is established in this paper. The variations of equivalent circuit parameters of the piezoelectric quartz crystal (PQC) during the enzymatic degradation are discussed. The initial hydrolysis rate of CS by HAse is obtained from the changes in viscosity and density with incubation time. Kinetic parameters (the Michaelis constant K(m) and the maximum hydrolysis rate V(max)) of the degradation process are estimated by using a linear method of Lineweaver-Burk plot. K(m) is 2.73 +/- 0.20 mg.ml(-1) and V(max) is -(5.43 +/- 0.38) x 10(-4) kg.m(-2).s(-1/2).min(-1.)

Journal Article↗

PubMed2001

Induction of C-reactive protein, serum amyloid P component, and kininogens in the submandibular and lacrimal glands of rats with experimentally induced inflammation.

The mRNAs for acute-phase proteins and kininogens were found to be increased in the submandibular gland (SMG) and extraorbital and intraorbital lacrimal gland (ELG and ILG) in response to experimentally induced inflammation in rats; i.e., 24 hours after subcutaneous injection of turpentine oil, mRNAs for C-reactive protein (CRP), serum amyloid P component (SAP), and H- and T-kininogens were induced in the SMG, ELG, and ILG of rats, whereas these mRNAs were not detected in the same tissues of normal control rats. The induction of mRNAs for these inflammatory proteins by turpentine oil was preceded by a transient increase in the level of mRNA for tumor necrosis factor-alpha (TNF-alpha) at 6 hours after subcutaneous injection of the oil. This was confirmed by injection of another inflammation inducer, lipopolysaccharide (LPS), which induced the TNF-alpha mRNA in the same way at 6 hours as turpentine oil did. The up-regulation of acute-phase proteins including kininogens in the SMG, ELG, and ILG suggest the existence of a strict defense system in the exocrine glands.

Animals↗

PubMed2001

Detection of widespread fluids in the Tibetan crust by magnetotelluric studies.

Magnetotelluric exploration has shown that the middle and lower crust is anomalously conductive across most of the north-to-south width of the Tibetan plateau. The integrated conductivity (conductance) of the Tibetan crust ranges from 3000 to greater than 20,000 siemens. In contrast, stable continental regions typically exhibit conductances from 20 to 1000 siemens, averaging 100 siemens. Such pervasively high conductance suggests that partial melt and/or aqueous fluids are widespread within the Tibetan crust. In southern Tibet, the high-conductivity layer is at a depth of 15 to 20 kilometers and is probably due to partial melt and aqueous fluids in the crust. In northern Tibet, the conductive layer is at 30 to 40 kilometers and is due to partial melting. Zones of fluid may represent weaker areas that could accommodate deformation and lower crustal flow.

Journal Article↗

PubMed2001

DNA capillary electrophoresis in entangled dynamic polymers of surfactant molecules.

Aqueous solutions of monomeric nonionic surfactants, n-alkyl polyoxyethylene ethers (C16E6, C16E8, C14E6), can be used as sieving matrixes for the separation of DNA fragments by capillary electrophoresis. Unlike ordinary polymer solutions, these surfactant solutions behave as dynamic polymers. By combining the "reversible gel" theory of DNA electrophoresis and the static and dynamic properties of wormlike surfactant micelles, a model is developed for describing the migration behavior of DNA molecules in these solutions. According to the model, the separation limit can be extended at low surfactant concentrations. Surfactant solutions as a separation medium provide many advantages over ordinary polymers, such as ease of preparation, solution homogeneity, stable structure, low viscosity, and self-coating property for reducing electroosmotic flow. More importantly, the properties of wormlike micelles (micelle size, entanglement concentration) can be adjusted by simply changing the monomer concentration, denaturant, and temperature to allow the separation of different size ranges of DNA fragments. Fast separation is achieved for DNA fragments ranging from 10 bp to 5 kb by using bare fused-silica columns. DNA sequencing fragments of BigDye G-labeled M13 up to 600 bases were separated within 60 min.

DNA↗

PubMed2001

Monitoring of Lactobacillus fermentation process by using ion chromatography with a series piezoelectric quartz crystal detector.

A new method monitoring Lactobacillus fermentation process, which combines ion chromatography (IC) with a series piezoelectric quartz crystal (SPQC) technique, is presented in this paper. Monitoring of the fermentation process was realized by examining the rate of production of lactic acid. An automatic membrane dialyser was used for the pretreatment of the sample in on-line monitoring. A mixture of p-hydroxybenzoic acid and N,N-diethylethanolamine was adopted as mobile phase and its flow rate was 0.8 ml/min. The effects of some fermentation conditions were also discussed in detail. Accordingly, the optimal fermentation conditions were obtained. This method is simple and convenient while the results obtained are accurate and reliable.

Carboxylic Acids↗

PubMed2001

Direct interaction between the subunit RAP30 of transcription factor IIF (TFIIF) and RNA polymerase subunit 5, which contributes to the association between TFIIF and RNA polymerase II.

The general transcription factor IIF (TFIIF) assembled in the initiation complex, and RAP30 of TFIIF, have been shown to associate with RNA polymerase II (pol II), although it remains unclear which pol II subunit is responsible for the interaction. We examined whether TFIIF interacts with RNA polymerase II subunit 5 (RPB5), the exposed domain of which binds transcriptional regulatory factors such as hepatitis B virus X protein and a novel regulatory protein, RPB5-mediating protein. The results demonstrated that RPB5 directly binds RAP30 in vitro using purified recombinant proteins and in vivo in COS1 cells transiently expressing recombinant RAP30 and RPB5. The RAP30-binding region was mapped to the central region (amino acids (aa) 47-120) of RPB5, which partly overlaps the hepatitis B virus X protein-binding region. Although the middle part (aa 101-170) and the N-terminus (aa 1-100) of RAP30 independently bound RPB5, the latter was not involved in the RPB5 binding when RAP30 was present in TFIIF complex. Scanning of the middle part of RAP30 by clustered alanine substitutions and then point alanine substitutions pinpointed two residues critical for the RPB5 binding in in vitro and in vivo assays. Wild type but not mutants Y124A and Q131A of RAP30 coexpressed with FLAG-RAP74 efficiently recovered endogenous RPB5 to the FLAG-RAP74-bound anti-FLAG M2 resin. The recovered endogenous RPB5 is assembled in pol II as demonstrated immunologically. Interestingly, coexpression of the central region of RPB5 and wild type RAP30 inhibited recovery of endogenous pol II to the FLAG-RAP74-bound M2 resin, strongly suggesting that the RAP30-binding region of RPB5 inhibited the association of TFIIF and pol II. The exposed domain of RPB5 interacts with RAP30 of TFIIF and is important for the association between pol II and TFIIF.

Animals↗

PubMed2001

Monitoring of bio-oxidation process of ferrous ion by using piezoelectric impedance analysis.

A new method of monitoring the bio-oxidation process of ferrous ion in the presence of Thiobacillus ferroxidans was proposed by piezoelectric impedance analysis. The time courses of the responses of impedance parameters for a quartz crystal in a culture system were simultaneously obtained and discussed. It was found that the frequency shift response originates mainly from the adsorption of bacterial metabolites on the surface of gold electrode. Experiments also examined the effect of culture temperature on the bio-oxidation process. Combined with the growth situation of the bacterium, an impedance response model reflecting the process was established. By fitting Delta f vs. time curves toward the proposed model, we obtained and discussed the bacterial growth parameters. The results showed that the proposed method could provide real time and multidimensional information to monitoring of the bio-oxidation process.

Acidithiobacillus thiooxidans↗

PubMed2001

Lithium suppresses excitotoxicity-induced striatal lesions in a rat model of Huntington's disease.

Huntington's disease is a progressive, inherited neurodegenerative disorder characterized by the loss of subsets of neurons primarily in the striatum. In this study, we assessed the neuroprotective effect of lithium against striatal lesion formation in a rat model of Huntington's disease in which quinolinic acid was unilaterally infused into the striatum. For this purpose, we used a dopamine receptor autoradiography and glutamic acid decarboxylase mRNA in situ hybridization analysis, methods previously shown to be adequate for quantitative analysis of the excitotoxin-induced striatal lesion size. Here we demonstrated that subcutaneous injections of LiCl for 16 days prior to quinolinic acid infusion considerably reduced the size of quinolinic acid-induced striatal lesion. Furthermore, these lithium pre-treatments also decreased the number of striatal neurons labeled with the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay. Immunohistochemistry and western blotting demonstrated that lithium-elicited neuroprotection was associated with an increase in Bcl-2 protein levels. Our results raise the possibility that lithium may be considered as a neuroprotective agent in treatment of neurodegenerative diseases such as Huntington's disease.

Animals↗