Biomedical subjects

Jian Yang

Publications and source records attributed to Jian Yang.

At least 73 records · Page 4Linked to original sources

PubMed2006

[Microenvironment of positive pressure powered air purifying medical protective equipment].

OBJECTIVE: To study the filtration efficiency of a positive pressure powered air purifying medical protective equipment and the effect of the flow rate on the microenvironment of the equipment. METHODS: The filtration efficiency of high efficiency particulate air (HEPA) filter was measured with the biologic aerosol of simulating virus (Escherichia coli bacteriophage f(2)). The simulation work was done at the walk rate of 4 km/h in summer. The effect of the flow rate on the oxygen content, the carbon dioxide content, the temperature and the humidity of the microenvironment of the equipment was investigated. The clinical experiments were conducted in three appointed hospital for fighting against SARS. RESULTS: The HEPA filter could filtrate 99.99% simulating viruses in the air. When the flow rate ranged from 75 to 125 L/min, the microenvironment parameters of the equipment were: the oxygen content was between 19.6% and 20.1% (the physiological safety limit is more than 14.6%); the carbon dioxide content ranged from 0.43% to 0.57% (the physiological safety limit is less than 1.0%); the temperature was between 32.0 degrees C to 32.2 degrees C; the humidity ranged from 49.7% to 59.4% (the physiological safety limit is the temperature 31 degrees C and the humidity 85% or temperature 38 degrees C and humidity 50%). Each microenvironment parameter met the demand of a healthy person under the normal workload. In the clinical experiments, the doctors wearing the equipment who performed the tracheotomy for a SARS patient in a deep coma were not infected. CONCLUSION: The medical protective equipment can protect the doctor and nurse in SARS contaminated areas effectively and improve their work conditions.

Air↗

PubMed2006

[Repairing large perforation of nasal septum with titanium membrane and local pedicled mucoperiosteum flap].

OBJECTIVE: To study a new treatment to repair large perforation of nasal septum with medical titanium membrane and local padicled mucoperiosteum flap. METHOD: The bottom mucoperiosteum of nasal cavity around the perforation of nasal septum were separated from the bone surface except with the margin part of perforation. Then the distal part of mucoperiosteum flap was incised and turn over to cover the perforation, free edge of the flap was sutured to secure immobilization. Finally, the Titanium membrane was cut to the right size to tuck into subperiosteal pocket around the perforation, and was sutured to the mucoperiosteal for added immobilization. RESULT: The perforations of nasal septum in 11 patients were closed satisfactorily. Perforation of nasal septum did not recur and the follow-up time ranged from half a year to 1 year. CONCLUSION: Titanium membrane is easy of application, and has good tissue tolerance. In our study, it is a good material to repair large perforation of nasal septum.

Adult↗

PubMed2006

[HLA-DM gene polymorphism in Cantonese with condyloma acuminata].

OBJECTIVE: To study the polymorphism of HLA-DM gene in Cantonese patients with condyloma acuminata(CA) and determine the susceptible genetic factors of CA. METHODS: DMA and DMB typing was performed in 98 Cantonese patients with CA and 93 healthy controls using restriction fragment length polymorphism method. RESULTS: The gene frequencies of DMA*0101 and DMB*0101 were significantly higher in the patients than in the controls (P<0.05 and P<0.01, respectively), and gene frequency of DMA*0102 was lower in patients than in the controls (P<0.01). Genotype frequencies of HLA-DM showed no significant difference between CA patients and the controls (P>0.05). CONCLUSION: DMA*0101 and DMB*0101 alleles may be the susceptibility genes or closely linked to the susceptibility gene in Cantonese patients with CA.

Adolescent↗

PubMed2006

[Cellular uptake and cytotoxicity of modified chitosans as gene carriers].

OBJECTIVE: To evaluate the effects of arginine modified chitosan or hexadecylated modified chitosan as gene carriers on the cellular uptake by vascular smooth muscle cells and its in vitro cytotoxicity. METHODS Plasmid DNA was labeled with alpha-32P-dATP and complexed with the modified chitosans or unmodified chitosan to form nanoparticle complexes by complex coacervation method. Uptake of all kinds of chitosan/ DNA nanoparticle complexes (CNC) by A10 cells was measured by beta-liquid scintillation counting. The in vitro cytotoxicity of the CNC was evaluated by the 3-[4,5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide (MTT) assay. RESULTS: The diameters of the CNC ranged from 55.9-174.9 nm and the zeta potentials were from 10. 8 mV for the arginine modified chitosan/DNA nanoparticle complexes (ACNC) to 1.8 mV for the hexadecylated chitosan/DNA nanoparticle complexes (HCNC). The cellular uptake of the modified chitosan/ DNA nanoparticle complexes (MCNC) by A10 cells increased significantly when compared with the unmodified chitosan/DNA nanoparticle complexes (UCNC) (P < 0.05), with the HCNC at N/P ratio of 1:1 and the ACNC at ratio of 8:1 showing the highest cellular uptake (1.3 fold higher than UCNC, P < 0.05). MCNC were much less cytotoxic when compared with Lipofectamine 2000-DNA nanoparticles. CONCLUSION: DNA nanoparticle complexes prepared with either arginine or hexadecylated modified chitosan can improve the cellular uptake of the DNA, while the in vitro cytotoxicity of both of the modified chitosan is much less than that of Lipofectamine 2000.

Animals↗

PubMed2006

[Study on the performances of the positive pressure powered air-filter protective hood].

The positive pressure powered air-filter protective hood can prevent physicians and nurses from being infected by serious respiratory infections. The contaminated air is filtered by the high efficiency specific air-filter (HESA) and then transported into the hood by a blower to form about 140 +/- 10 Pa positive pressure environment, which makes the air in hood overflow out from the lower part of the hood, by which carbon dioxide and vapor can be removed, and excreted. The HESA's filters of simulative virus up to 99.9999% with the structure of double layers filtering. With going at 4 km/h pace on a walking vehicle wearing the hood, the testees' heart rate is 90-105/min oxygen saturation of the blood(SPO2) is 97%-98%. When the air flow is from 75 L/min to 125 L/min, this can meet the testees' physiological demand under heavy workload. Clinical trial results show that the hood can effectively protect the physicians and nurses from infection.

Adult↗

PubMed2006

[Solubilities of ephedrine and d-pseudo-ephedrine from different sizes of ultramicro-particles of the compound traditional Chinese herbs Maxing Shigan decoction].

OBJECTIVE: To compare the solubilities of ephedrine and d-pseudo-ephdrine in the compound of traditional Chinese drugs--Maxing Shigan decoction with and without ultramicro-pulverizations using a RP-HPLC procedure. METHOD: The analytical column was a YMC ODS-C18(4.6 mm x 150 mm,4 microm). A mixture of water-acetonitrile-sodium dodecyl sulfate-phosphorous acid (650:350:5:1) was used as the mobile phase at flow rate of 1.5 mL x min(-1). The column temperature was 50 degrees C and the wavelength was 210 nm. RESULT: In this way, ephedrine and d-pseudo-ephedrine of the compound samples can be separated well and showed significant differences before and after the ultramicro-pulverizations. CONCLUSION: For the Maxing Shigan decoction, the dissolution rates and solubilites of ephedrine and d-pseudo-ephedrine ultramicro-pulverization were greatly improved.

Calcium Sulfate↗

PubMed2006

[Liquid flow field measurement in a tube with a combination of stenosis and bifurcation].

Two-D liquid velocity field in a tube with a combination of a stenosis and a bifurcation was measured with refractive index matching technique using Laser Doppler Velocimeter (LDV). The flow ratio of main tube to bypass was 1:4. It is found that the axial velocity profile has two peaks in the XOY plane which is skewed to the main tube wall facing the flow from the bypass, and it manifests itself in the form of "M" in the XOZ plane. A two counter-rotating vortices in the main tube cross section downstream the conjunction region is also detected.

Laser-Doppler Flowmetry↗

PubMed2005

Oxysterol 22(R)-hydroxycholesterol induces the expression of the bile salt export pump through nuclear receptor farsenoid X receptor but not liver X receptor.

Oxysterols are intermediates in the synthesis of bile acids and steroid hormones from cholesterol and function as ligands for liver X receptor (LXR). Bile salt export pump (BSEP) is responsible for canalicular secretion of bile acids and is tightly regulated by its substrates bile acids through nuclear receptor farnesoid X receptor (FXR). In a microarray study using human hepatocytes, BSEP was markedly induced not only by chenodeoxycholic acid (CDCA) but also by oxysterol 22(R)-hydroxycholesterol [22(R)-OHC]. We hypothesized that the expression of BSEP was induced by oxysterols through activation of LXR. To test the hypothesis, human primary hepatocytes or hepatoma cells were treated with 22(R)-OHC, and expression of BSEP was determined. The level of BSEP mRNA was increased as much as 5-fold upon oxysterol induction. In contrast to our hypothesis, the oxysterol-induced up-regulation of BSEP is mediated through FXR but not LXR. BSEP promoter activity was markedly induced by 22(R)-OHC in the presence of FXR but not LXRs. Mutation of the FXR element IR1 in the BSEP promoter significantly reduced its ability to respond to oxysterol induction. To determine whether 22(R)-OHC and CDCA bind to similar structural features of FXR, site-directed mutagenesis was performed in the FXR ligand binding domain. Mutation of residues R331 and I352 abolished activation mediated by CDCA and 22(R)-OHC. In contrast, substitution of residues L340 and R351 differentiated CDCA- and 22(R)-OHC-mediated activation. In conclusion, oxysterol 22(R)-OHC functions as an FXR ligand to induce BSEP expression and differs in the binding with FXR from CDCA.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2005

Transplacental transfer of butyltins to fetus of Dall's porpoises (Phocoenoides dalli).

Here we provided evidence, for the first time, on the placental transfer of butyltin species in Dall's porpoise (Phocoenoides dalli). The maternal to fetal transfer of butyltins including monobutyltin (MBT), dibutyltin (DBT) and tributyltin (TBT) was investigated in a mother-fetus pair collected off the Sanriku coast of Japan. The maternal individual was found contaminated as its liver accumulated the highest concentrations of all MBT, DBT and TBT. This study revealed that the transfer rate was about 0.3% for total butyltins to a fetus of about 6 months old. Unlike in the mother, the fetal liver does not appear to be a preferential organ for accumulation of all the butyltins. In a approximately 100 kg-weight mother Dall's porpoise and its fetus of 2.21 kg-weight about 1,269 microg (TBT, 578 microg; DBT, 480 microg; MBT, 211 microg) and 4.2 microg of total butyltins (TBT, 1.1 microg; DBT, 2.1 microg; MBT, 0.96 microg) were found, respectively.

Animals↗

PubMed2005

Synthesis and evaluation of poly(diol citrate) biodegradable elastomers.

Herein, we report the synthesis and evaluation of a novel family of biodegradable and elastomeric polyesters, poly(diol citrates). Poly(diol citrates) were synthesized by reacting citric acid with various diols to form a covalent cross-linked network via a polycondensation reaction without using exogenous catalysts. The tensile strength of poly(diol citrates) were as high as 11.15+/-2.62 MPa and Young's modulus ranged from 1.60+/-0.05 to 13.98+/-3.05 MPa under the synthesis conditions that were investigated. Elongation was as high as 502+/-16%. No permanent deformation was found during mechanical tests. The equilibrium water-in-air contact angles of measured poly(diol citrates) films ranged from 15 degrees to 53 degrees . The mechanical properties, degradation and surface characteristics of poly(diol citrates) could be controlled by choosing different diols as well as by controlling the cross-link density of the polyester network. Various types of poly(diol citrate) scaffolds were fabricated to demonstrate their processing potential. These scaffolds were soft and could recover from deformation. In vitro and in vivo evaluation using cell culture and subcutaneous implantation, respectively, confirmed cell and tissue compatibility. The introduction of poly(diol citrates) will expand the repertoire of currently available biodegradable polymeric elastomers and should help meet the requirements of tissue engineering applications.

Animals↗

PubMed2005

Trace elements and butyltins in a Dall's porpoise (Phocoenoides dalli) from the Sanriku coast of Japan.

Concentrations and body burdens of 14 trace elements (Hg, Cr, Mn, Co, Cu, Zn, Sr, Ag, Cd, V, Se, Pb, Mo, and Fe) and butyltins (BTs) (tributyltin TBT, dibutyltin DBT, and monobutyltin MBT) were determined in various tissues of a mature male Dall's porpoise (Phocoenoides dalli) collected off the Sanriku coast of Japan. Selective accumulation in this porpoise was observed for Hg, Mn, Cu, Ag, Mo, Fe, and total BTs (TBT, DBT, and MBT) in the liver, Cd in the kidney, Zn, Sr, V, Pb, and Co in the bone, and Se in the skin. In contrast, Cr concentrations in all tissues were similar. This distribution pattern in this mature porpoise was in general agreement with the accumulation characteristics of trace elements and butyltins reported for other marine mammals. The whole body of the porpoise contained approximately 62 g Fe, 8.8 g Zn, 4.0 g Sr, 0.6g Se, 0.41 g Cu, 0.19 g Hg, 0.17 g Cd, 0.16 g Mn, 0.05 g Cr, 0.009 g Ag, 0.008 g Mo, 0.005 g Pb, 0.004 g Co, and 0.7 mg of BTs (0.4 mg TBT, 0.2 mg DBT, and 0.1 mg MBT). Metabolism of TBT to its breakdown products of this porpoise seems to be limited, since TBT still accounted for about half of the total burden of BTs. As in the cases of Hg, Mn, Cu, Se, and Fe, the muscle was the most important reservoir (43%) for the whole body burden of total BTs, 80% of which was TBT, and thus muscle played a crucial role in the higher body composition of TBT in this Dall's porpoise.

Animals↗

PubMed2005

The ROC analysis for different time points during oral glucose tolerance test.

This purpose was to discuss optimal reference value for normal glucose tolerance (NGT) at different time points during an oral glucose tolerance test (OGTT) by receiver operating characteristic (ROC) analysis. One thousand seven hundred and forty-six subjects from March 2004 to March 2005 were given 75 g OGTT and the blood samples were collected at 0, 30, 60, 120 and 180 min for glucose measurement. Other demographic data (e.g. age, sex, body mass index, BMI) were also recorded. The status of NGT, impaired glucose tolerance (IGT), impaired fasting glucose (IFG) and DM was determined according to American Diabetes Association (ADA) criteria. IGT and IFG were merged as impaired glucose regulation (IGR). Using IGR as the assumed test, the cutoff values at 0, 30, 60, 120 and 180 min during OGTT for normal reference range were calculated by ROC analysis. The cutoff values were 5.6, 9.5, 10.1, 7.8 and 6.1 mmol/l at 0, 30, 60, 120 and 180 min, respectively, in whole subjects. In addition, we provided the ROC information in age-stratified groups since there are differences among different age groups. When the results of OGTT were considered, the present study provided a reference range value to evaluate the status of glucose tolerance. Because of the heterogeneity of diabetes, further studies are necessity. And the sample collection is continuing.

Aged↗

PubMed2005

Genome dynamics and diversity of Shigella species, the etiologic agents of bacillary dysentery.

The Shigella bacteria cause bacillary dysentery, which remains a significant threat to public health. The genus status and species classification appear no longer valid, as compelling evidence indicates that Shigella, as well as enteroinvasive Escherichia coli, are derived from multiple origins of E.coli and form a single pathovar. Nevertheless, Shigella dysenteriae serotype 1 causes deadly epidemics but Shigella boydii is restricted to the Indian subcontinent, while Shigella flexneri and Shigella sonnei are prevalent in developing and developed countries respectively. To begin to explain these distinctive epidemiological and pathological features at the genome level, we have carried out comparative genomics on four representative strains. Each of the Shigella genomes includes a virulence plasmid that encodes conserved primary virulence determinants. The Shigella chromosomes share most of their genes with that of E.coli K12 strain MG1655, but each has over 200 pseudogenes, 300 approximately 700 copies of insertion sequence (IS) elements, and numerous deletions, insertions, translocations and inversions. There is extensive diversity of putative virulence genes, mostly acquired via bacteriophage-mediated lateral gene transfer. Hence, via convergent evolution involving gain and loss of functions, through bacteriophage-mediated gene acquisition, IS-mediated DNA rearrangements and formation of pseudogenes, the Shigella spp. became highly specific human pathogens with variable epidemiological and pathological features.

DNA Transposable Elements↗

PubMed2005

High-yield synthesis of single-crystalline antimony telluride hexagonal nanoplates using a solvothermal approach.

We report a high-yield synthesis of single-crystal hexagonal Sb2Te3 nanoplates using a solvothermal approach. The experimental results show that the concentration of capping agent CTAB played a key role in the formation of nanoplates. This new nanostructure may provide opportunity for the exploration of novel thermoelectric properties and have potential applications in thermoelectric nanodevices.

Alloys↗

PubMed2005

Effects of iptakalim on extracellular glutamate and dopamine levels in the striatum of unilateral 6-hydroxydopamine-lesioned rats: a microdialysis study.

In a previous study, we demonstrated that iptakalim (Ipt) significantly ameliorated hypolocomotion and catalepsy induced by haloperidol and rotenone in rats. In order to further understand the mechanism(s), using a rat model of Parkinson's disease (PD) established by unilateral 6-hydroxydopamine (6-OHDA) administration to the substantia nigra pars compacta (SNpc) and reverse microdialysis techniques with high performance liquid chromatography (HPLC), we investigated the effects of Ipt on extracellular levels of glutamate, dopamine (DA) and its metabolite dihydroxyphenylacetic acid (DOPAC) in the striatum of conscious and freely moving rats. The results indicated that unilateral 6-OHDA-lesioned rats have a significantly higher level of extracellular glutamate and a lower level of extracellular DOPAC in the lesioned-side of the striatum, and a lower level of extracellular DA in both sides of the striatum compared to the striatum of control rats. Ipt reduced extracellular glutamate levels in both sides of striatum of the lesioned and control rats in a concentration-dependent manner. Ipt, at lower concentrations (0.01, 0.1, 1 microM), enhanced extracellular DA levels in the lesioned-side striatum of the unilateral 6-OHDA-lesioned rats, while causing no significant changes in the intact side striatum, and even a significant decline in striatum of control rats at higher concentrations of Ipt (10, 100 microM). In addition, Ipt also caused a significant decline in the extracellular DOPAC levels in the lesioned-side striatum of unilateral 6-OHDA-lesioned rats. These data suggest that the major mechanism underlying the ameliorative effects of Ipt on the behavior in 6-OHDA-lesioned rats is the alteration of levels of extracellular neurotransmitters, such as glutamate and DA in the striatum of unilateral 6-OHDA-lesioned rats.

3,4-Dihydroxyphenylacetic Acid↗

PubMed2005

The orientation parameter for energy transfer in restricted geometries including block copolymer interfaces: a Monte Carlo study.

We describe Monte Carlo simulations of resonance energy transfer (RET) experiments for immobile donor (D) and acceptor (A) dyes confined to planar, cylindrical, and spherical restricted geometries. We compare values of the quantum efficiency (PhiET) evaluated through consideration of individual donor-acceptor pairs, with values calculated assuming a pre-averaged value of the orientation parameter /kappa/2 = 0.476 appropriate for infinite three dimensional (3D) space. For dyes confined to restricted geometries where the length scale of the confining dimension is less than or equal to the Förster radius R0, the coupling of the orientation parameter and the donor-acceptor distance becomes noticeable. Values of Phi(ET) obtained by proper consideration of the orientation parameter are smaller than those calculated using /kappa/2 = 0.476. We use this Monte Carlo method to reanalyze the fluoresce decay measured from dye-labeled poly(isoprene-b-methyl methacrylate) diblock copolymer with lamellar structure,(1) from which the interface thickness for PI-PMMA lamella can be retrieved. We found the retrieved interface thickness is sensitive to the choice of dipole orientation. If all dipoles in the confined polymer interface have a random orientation, the value of interface thickness was found to be 0.9 +/- 0.2 nm through consideration of individual dipole orientations. Assumption of /kappa/2 = 0.476 in the FRET calculations leads to a larger value of interface thickness (1.3 +/- 0.2 nm) due to the neglect of the coupling between dipole orientation and D-A distance for the dyes confined to lamellar interfaces.

Energy Transfer↗

PubMed2005

Development of a large-scale chemogenomics database to improve drug candidate selection and to understand mechanisms of chemical toxicity and action.

Successful drug discovery requires accurate decision making in order to advance the best candidates from initial lead identification to final approval. Chemogenomics, the use of genomic tools in pharmacology and toxicology, offers a promising enhancement to traditional methods of target identification/validation, lead identification, efficacy evaluation, and toxicity assessment. To realize the value of chemogenomics information, a contextual database is needed to relate the physiological outcomes induced by diverse compounds to the gene expression patterns measured in the same animals. Massively parallel gene expression characterization coupled with traditional assessments of drug candidates provides additional, important mechanistic information, and therefore a means to increase the accuracy of critical decisions. A large-scale chemogenomics database developed from in vivo treated rats provides the context and supporting data to enhance and accelerate accurate interpretation of mechanisms of toxicity and pharmacology of chemicals and drugs. To date, approximately 600 different compounds, including more than 400 FDA approved drugs, 60 drugs approved in Europe and Japan, 25 withdrawn drugs, and 100 toxicants, have been profiled in up to 7 different tissues of rats (representing over 3200 different drug-dose-time-tissue combinations). Accomplishing this task required evaluating and improving a number of in vivo and microarray protocols, including over 80 rigorous quality control steps. The utility of pairing clinical pathology assessments with gene expression data is illustrated using three anti-neoplastic drugs: carmustine, methotrexate, and thioguanine, which had similar effects on the blood compartment, but diverse effects on hepatotoxicity. We will demonstrate that gene expression events monitored in the liver can be used to predict pathological events occurring in that tissue as well as in hematopoietic tissues.

5-Aminolevulinate Synthetase↗

PubMed2005

The complete sequence and analysis of the large virulence plasmid pSS of Shigella sonnei.

The complete sequence of pSS, which is the large virulence plasmid of Shigella sonnei, was determined. The 214-kb plasmid is composed of segments of virulence-associated genes, the O-antigen gene clusters, a range of replication and maintenance genes, and large numbers of insertion sequence (IS) elements. Two hundred and forty-one open reading frames (ORFs) were identified, of which 117 are highly homologous to IS elements or transposases, 57 are homologous to known pathogenesis-associated proteins, and 30 are related to replication, plasmid maintenance, or other metabolic functions. Thirty-seven ORFs have no similarity to proteins with a known function, including two with no significant similarity to any hypothetical proteins. Interestingly, 10 ORFs encoding O-antigen gene clusters were identified on the plasmid and this is markedly different from most other Shigella spp. virulent plasmids. A novel toxin-antitoxin system, a series of stbDE homologs, was found on the plasmid immediately downstream of the replication region; the sole segregation stability system may be responsible for the instability of pSS. The pSS plasmid is a mixture of genes with different origins and functions. The sequence suggests a remarkable history of IS-mediated recombination and acquisition of DNA across a range of bacterial species.

Bacterial Proteins↗