Biomedical subjects

Min Xu

Publications and source records attributed to Min Xu.

At least 37 records · Page 2Linked to original sources

PubMed2006

Identification of a stage-specific permissive in vitro culture environment for follicle growth and oocyte development.

The availability of viable oocytes is the limiting factor in the development of new reproductive techniques. Many attempts have been made to grow immature oocytes in vitro during recent decades. Recently, a modified alginate-based three-dimensional culture system was designed to support the growth and maturation of multilayered secondary follicles. This system was able to produce oocytes that successfully completed meiosis, fertilization, and development to the blastocyst stage. Subsequent attempts to culture two-layered secondary follicles were unsuccessful under the original conditions. Herein, we investigated the effect of alginate consistency on two-layered follicle growth and oocyte developmental competence by encapsulating follicles into alginate scaffolds of various concentrations. Although there were no significant differences in survival rates, 0.25% and 0.5% alginate supported more rapid growth of follicles and antrum formation compared with 1.5% and 1.0% alginate after 8 days of culture. Alginate scaffold concentration also affected the proliferation and differentiation of somatic cells (theca and granulosa cells), measured in terms of morphological changes, steroid profiles (androstenedione, estradiol, and progesterone), and specific molecular markers (Fshr, Lhcgr, and Gja1). Theca cell proliferation and steroid production were hindered in follicles cultured in 1.5% alginate. In vitro fertilization and embryo culture revealed that oocytes obtained from 0.25% alginate retained the highest developmental competence. Overall, the present study showed that the alginate scaffold consistency affects folliculogenesis and oocyte development in vitro and that the alginate culture system can and should be tailored to maximally support follicle growth depending on the size and stage of the follicles selected for culture.

Androstenedione↗

PubMed2006

Electrochemiluminescence from successive electro- and chemo-oxidation of rifampicin and its application to the determination of rifampicin in pharmaceutical preparations and human urine.

A novel electrochemiluminescence (ECL) type was proposed based on successive electro- and chemo-oxidation of oxidable analyte, which was different from both annihilation and coreactant ECL types in mechanism. Rifampicin was used as a model compound. No any chemiluminescence (CL) was produced by either electrochemical oxidation or chemical oxidation of rifampicin in KH(2)PO(4)--Na(2)B(4)O(7) (pH 6.6) buffer-dodecyl trimethyl ammonium chloride (DTAC) solution. However, an ECL was observed by electrochemical oxidization of rifampicin in the same solution in the presence of oxidant such as dissolved oxygen, activated oxygen and potassium peroxydisulfate (K(2)S(2)O(8)). The ECL was attributed to electrochemical oxidation of rifampicin to form semiquinone free radical, and then subsequently chemical oxidation of the formed radical by oxidant to form excited state rifampicin quinone. The proposed ECL type introduced additional advantages such as high selectivity, simple and convenient operation, and effective avoidance of side reaction that often took place in homogenous CL reaction, and will open a novel application field. In addition, with the ECL in the presence of K(2)S(2)O(8) as oxidant, a flow injection ECL method for the determination of rifampicin was proposed. The ECL intensity was linear with rifampicin concentration in the range of 1.0 x 10(-7) to 4.0 x 10(-5) mol l(-1) and the limit of detection (s/n=3) was 3.9 x 10(-8) mol l(-1). The proposed method was applied to the determination of rifampicin in pharmaceutical preparations and human urine.

Bicarbonates↗

PubMed2006

Reduction of intracellular pH inhibits the expression of VEGF in K562 cells after targeted inhibition of the Na+/H+ exchanger.

To explore the effect of inhibition of Na(+)/H(+) exchanger isoform 1 (NHE1) on the expression of vascular endothelial growth factor (VEGF) mRNA and protein in human myeloid K562 cells. The expression of VEGFmRNA was detected by RT-PCR technique. The levels of VEGF protein were measured by Western blotting and immunocytochemistry assay. pHi values were measured with fluorescence spectrophotometer. The three RT-PCR products detected were VEGF121, VEGF165, and VEGF189, respectively. Treatment of K562 cells either with amiloride (an inhibitor of NHE1) or with 5-(N-ethyl-N-isopropyl)-amiloride (EIPA, a selective inhibitor of NHE1) resulted in significant decrease of VEGF mRNA and VEGF protein levels. Either amiloride or EIPA decreased intracellular pH (pHi) values in K562 cells. These data strongly suggested that the expression of VEGF mRNA and protein in K562 cells was inhibited accompanying its reduction in pHi value after targeted inhibition of NHE1.

Amiloride↗

PubMed2006

Genetic analysis of 4 new mutants at the unstable k2 Mdh1-n y20 chromosomal region in soybean.

In soybean (Glycine max (L.) Merr.), a chromosomal region defined by 3 closely linked loci, k2 (tan-saddle seed coat), Mdh1-n (malate dehydrogenase 1 null), and y20 (yellow foliage), is highly mutable. A total of 31 mutants have been reported from this region. In this study, a mutation with tan-saddle seed coat was found from bulk-harvested seed of cultivar Kenwood. Genetic analysis established that this tan-saddle seed coat mutation is allelic to the k2 locus and inherited as a recessive gene. Simple sequence repeat analysis showed that this mutant is not a contaminant from other existing k2 mutants. The mutant was named Kenwood-k2. To test for genetic instability at the k2 Mdh1-n y20 chromosomal region, Kenwood-k2 was crossed reciprocally with cultivars Harosoy and Williams. No new mutants were found in F2 families. In the genetic instability tests of T239 (k2) with cultivar Williams, 3 new mutants with yellow foliage (y20) and malate dehydrogenase 1 null (Mdh1-n) were identified. In the genetic instability tests of T261 (k2 Mdh1-n) with cultivar Williams, no new mutants were found. The Kenwood-k2 and the 3 yellow-foliage, malate dehydrogenase 1-null mutants provide additional genetic materials to study chromosomal aberrations in this mutable/unstable chromosomal region.

Alleles↗

PubMed2006

Drosophila Ecp is a novel ribosome associated protein interacting with dRPL5.

Drosophila Ecp is a phylogenetically conserved protein with homologs in most eukaryotes. Studies on Ecp homologs in rat and human suggest those proteins might be involved in cell cycle control, cell proliferation, and learning and memory. However, the molecular function of Ecp itself remains unclear. We show that both the mRNA and protein of ecp are ubiquitously expressed during the entire fly embryogenesis and life cycle. Results of co-immunoprecipitation show that Ecp forms a stable complex with many ribosomal proteins, including dRPL5. The binding of Ecp to dRPL5 was confirmed by GST pulldown. Furthermore, Ecp was found to cosediment with ribosome subunits in a sucrose gradient. These results indicate that Ecp might be a novel ribosome associated protein interacting with dRPL5.

Animals↗

PubMed2006

WEEE recovery strategies and the WEEE treatment status in China.

The electric and electronic equipment has been developed, applied, and consumed world wide at a very high speed. Subsequently, the ever-increasing amount of waste electric and electronic equipment (WEEE) has become a common problem facing the world. In view of the deleterious effects of WEEE on the environment and the valuable materials that can be reused in them, legislations in many countries have focused their attention on the management of WEEE, and new techniques have been developed for the recovery of WEEE. In China, rapid economic growth, coupled with urbanization and growing demand for consumer goods, has increased the consumption of EEE in large quantity, thus made the WEEE manifold rapidly, posing a severe threat to the environment and the sustainable economic growth as well. This article reviewed the implementation of strategies of WEEE treatment and the recovery technologies of WEEE. It presented the current status of WEEE and corresponding responses adopted so far in China. The concept and implementation of scientific development is critical to the sector of electronics, one of the important industrial sectors in China's economy. To achieve this objective, it is significant to recycle WEEE sufficiently to comply with regulations regarding WEEE management, and to implement green design and cleaner production concepts within the electronics industry to comply with the upcoming EU and China legislation in a proactive manner.

China↗

PubMed2006

Quantum chemical study of adsorption and dissociation of H2S on the gallium-rich GaAs (001)-4 x 2 surface.

H(2)S adsorption and dissociation on the gallium-rich GaAs(001)-4 x 2 surface is investigated using hybrid density functional theory. Starting from chemisorbed H(2)S on the GaAs(001)-4 x 2 surface, two possible reaction routes have been proposed. We find that H(2)S adsorbs molecularly onto GaAs(001)-4 x 2 via the formation of a dative bond, and this process is exothermic with adsorption energy of 6.6 kcal/mol. For the first reaction route, one of the H atoms from the chemisorbed H(2)S is transferred to a second-layer As atom and the dissociated SH is inserted into the Ga-As bond with an activation barrier of 8.2 kcal/mol, which is found to be 29.3 kcal/mol more stable than the reactants. For the second case, the dissociated species may insert themselves into the Ga-Ga dimer resulting in the Ga-H-Ga and Ga-HS-Ga bridge-bonded states, which are found to be 29.8 and 22.2 kcal/mol more stable than the reactants, respectively. However, the calculations also show that the activation barrier (16.1 kcal/mol) for chemisorbed H(2)S dissociation through the second route is higher than the transfer of one H atom into a second-layer As atom. As a result, we conclude that sulfur insertion into the Ga-As bond is more kinetically favorable.

Journal Article↗

PubMed2006

Analysis of clinical manifestations, mutant gene and encoded protein in two Chinese MYH9-related disease families.

BACKGROUND: MYH9-related disease is a rare autosomal dominant disorder characterized by the triad of giant platelet, thrombocytopenia and inclusion bodies in neutrophil. In recent years, much progress has been made in the investigation of its clinical feature and pathogenesis. METHODS: Clinical manifestations were analyzed in two Chinese MYH9-related disease families. Polymerase chain reaction (PCR), DNA sequencing and CpoI restrictive endonuclease map analysis were used to identify spot mutation in nonmuscle myosin heavy chain 9 (MYH9) gene. Indirect immunofluence combined propidium iodine (PI) nuclei count-staining technology was applied to probe nonmuscle myosin heavy chain IIA (NMMHC-A) in MYH9-related disease neutrophils and platelets. Western blot was undergone to examine the expression of NMMHC-A in MYH9-related disease patients. RESULTS: All of the patients manifested with the typical triad, mild to moderate bleeding tendency were their common clinical feature, some patients were accompanied by renal lesion. G5521A mutation in MYH9 gene was identified in both families. Spindle-like inclusions with yellow fluorescence in MYH9-related disease neutrophils were clearly revealed by indirect immunofluence combined PI nuclei count-staining technology, which matched very well with the inclusions, detected by Wright-Giemsa's stain. An upregulation of NMMHC-A in MYH9-related disease neutrophils was observed by Western blotting analysis. CONCLUSION: Mutation of MYH9 gene exists in cases of Chinese MYH9-related disease. In the two families, the point mutation was located in exon 38(G5521A), and the transference rule of the MYH9 gene mutation is corresponding with clinical phenotype distribution. Indirect immunofluorescence combining with PI nuclei staining technology is sensitive and more specific than Wright-Giemsa's staining in detecting MYH9-related disease inclusions, with which we might easily distinguish MYH9-related disease inclusions from infection-associated inclusions. The expression of the NMMHC-A in MYH9-related disease neutrophils was upregulated than normal control.

Adult↗

PubMed2006

Integrative Array Analyzer: a software package for analysis of cross-platform and cross-species microarray data.

The rapid accumulation of microarray data translates into an urgent need for tools to perform integrative microarray analysis. Integrative Array Analyzer is a comprehensive analysis and visualization software toolkit, which aims to facilitate the reuse of the large amount of cross-platform and cross-species microarray data. It is composed of the data preprocess module, the co-expression analysis module, the differential expression analysis module, the functional and transcriptional annotation module and the graph visualization module.

Algorithms↗

PubMed2006

Optimization of wastewater treatment alternative selection by hierarchy grey relational analysis.

This paper describes an innovative systematic approach, namely hierarchy grey relational analysis for optimal selection of wastewater treatment alternatives, based on the application of analytic hierarchy process (AHP) and grey relational analysis (GRA). It can be applied for complicated multicriteria decision-making to obtain scientific and reasonable results. The effectiveness of this approach was verified through a real case study. Four wastewater treatment alternatives (A(2)/O, triple oxidation ditch, anaerobic single oxidation ditch and SBR) were evaluated and compared against multiple economic, technical and administrative performance criteria, including capital cost, operation and maintenance (O and M) cost, land area, removal of nitrogenous and phosphorous pollutants, sludge disposal effect, stability of plant operation, maturity of technology and professional skills required for O and M. The result illustrated that the anaerobic single oxidation ditch was the optimal scheme and would obtain the maximum general benefits for the wastewater treatment plant to be constructed.

Computer Simulation↗

PubMed2006

[Spiral computed tomography images of extraluminal type gastric stromal tumors].

OBJECTIVE: To evaluate the diagnostic value of spiral CT and its reconstruction techniques in the diagnosis of extraluminal type gastric stromal tumors. METHODS: The data of spiral CT performed 1 week before operation of 17 extraluminal type cases, 11 males and 6 females, aged 35.5 (13-67), from 33 patients of gastric stromal tumors proved by pathology and immunohistochemistry, were analyzed retrospectively. RESULTS: The accuracy rates of level diagnosis and qualitative diagnosis of extraluminal type gastric stromal tumor by spiral CT were 88.2% and 82.4% respectively. The main CT manifestations included: (1) extraluminal mass connected with the gastric wall, with round or lobulated margin and characteristic horn-like appearance and direct invasion, more than 5.0 cm in diameter; (2) inhomogeneous density of mass, including mild to moderate uneven enhancement in artery phase and obvious enhancement in vein and delay phase in 15 cases, and obvious enhancement in artery phase and decrease of enhancement in portal vein phases in 2 cases. (3) Irregular niches and sinus in the margins of the intraluminal masses (n = 11) and unclear border of the masses and invasion into nearby structures (n = 9); (4) connection of the tumor and stomach wall by broad boundary or failure to distinguish the tumor and stomach wall; and (5) invasion to the surrounding tissues and organs as a sign of malignant tumors. CONCLUSION: Spiral CT and its reconstruction techniques have important value in level diagnosis and qualitative diagnosis of extraluminal type gastric stromal tumors.

Adolescent↗

PubMed2006

Further understanding human disease genes by comparing with housekeeping genes and other genes.

BACKGROUND: Several studies have compared various features of heritable disease genes with other so called non-disease genes, but they have yielded some conflicting results. A potential problem in those studies is that the non-disease genes contained a large number of essential genes--genes which are indispensable for humans to survive and reproduce. Since a functional disruption of an essential gene has fatal consequences, it's more reasonable to regard essential genes as extremely severe "disease" genes. Here we perform a comparative study on the features of human essential, disease, and other genes. RESULTS: In the absence of a set of well defined human essential genes, we consider a set of 1,789 ubiquitously expressed human genes (UEHGs), also known as housekeeping genes, as an approximation. We demonstrate that UEHGs are very likely to contain a large proportion of essential genes. We show that the UEHGs, disease genes and other genes are different in their evolutionary conservation rates, DNA coding lengths, gene functions, etc. Our findings systematically confirm that disease genes have an intermediate essentiality which is less than housekeeping genes but greater than other human genes. CONCLUSION: The human genome may contain thousands of essential genes having features which differ significantly from disease and other genes. We propose to classify them as a unique group for comparisons of disease genes with non-disease genes. This new way of classification and comparison enables us to have a clearer understanding of disease genes.

Adolescent↗

PubMed2006

A preliminary study on sorption, diffusion and degradation of mustard (HD) in cement.

A preliminary study has been done to examine the sorption, diffusion and degradation of mustard (HD) in cement. The sample of dried cement paste is a meso-porous adsorbant with a BET surface area around 40.8 m2/g, which is able to adsorb vapor of HD at room temperature and to result in a multiple-layer isotherm of II type. The molecule of HD seemed to chemically adsorb onto cement surface. Droplet of HD contaminating cement was able to be degraded into less toxic products, but in a very low rate of k = 4.8 x 10(-5) min(-1) and t(1/2) = 16 x 10(4) min at room temperature. Droplet of HD is able to penetrate through the layer of cement, but a cement plate of 8mm can protect against HD droplets over 48 h. A decrease of thickness for cement layer or addition of sand in cement would lead to lower the protection time against HD droplets. The diffusion coefficient of HD molecule in cement was determined, about 1.3 x 10(-4) cm2/min and of a typical diffusion in solid.

Absorption↗

PubMed2006

Patients' outcome after total hip arthroplasty: a comparison between the Western Ontario and McMaster Universities index and the Oxford 12-item hip score.

This prospective cohort study included 402 patients who had primary total hip arthroplasty. The Western Ontario and McMaster Universities Index (WOMAC) and the Oxford 12-item Hip Score (OHS) were used to assess patients preoperatively and at 1 year postoperation. The OHS has a higher responsiveness than the WOMAC in the global scale and in the pain subscale. However, the WOMAC has better responsiveness in its function scale. The point estimate of relative precision of measuring postoperative quality of life shows that the OHS has a tendency toward a better performance than the WOMAC; however, this finding is not statistically significant. The OHS also demonstrates similar floor and ceiling effect patterns as does the WOMAC. We recommend that the choice should depend on which scale researchers are using to power a study.

Arthroplasty, Replacement, Hip↗

PubMed2006

High-avidity antitumor T-cell generation by toll receptor 8-primed, myeloid- derived dendritic cells is mediated by IL-12 production.

BACKGROUND: High-level production of heterodimeric p70 interleukin (IL)-12 by myeloid-derived dendritic cells (DCs) requires 2 signals: interferon gamma (IFN-gamma) and a maturation signal provided by CD40 ligation (CD40L) or lipopolysaccharide (LPS). METHODS: In the current study we demonstrate that signaling through toll-like receptor (TLR) 8, but not TLR3, TLR2, or TLR4, provides a priming signal to myeloid-derived DC for high IL-12 p70 heterodimer production. RESULTS: All the TLR agonists induced maturation of DC as evidenced by increased expression of CD83, CD80, and CD86. Both IFN-gamma and TLR7/8 agonist R848 increased expression of TLR8 in immature monocyte-derived DCs. The combination of TLR7/8 agonist R848 and maturation signals LPS or CD40L induced high-level expression of IL-12p35 and p40 similar to that induced by IFN-gamma plus LPS. In contrast, receptor agonists specific for TLR7 did not prime for IL-12 production. The p70 IL-12 produced by the TLR8-primed DC polarized CD4+ T for Th1 cytokine production and induced CD8+ T cells, displaying high functional avidity with enhanced tumor cell recognition. CONCLUSIONS: The data suggest that toll 8 receptor agonists are useful for inducing type-1 polarized DCs for vaccine design in treating cancer and infectious disease.

Antigens, CD↗

PubMed2006

Delays worsen quality of life outcome of primary total hip arthroplasty.

Although there are indications of health status deterioration for patients while waiting for elective total hip arthroplasties, controversy exists regarding the effect of waiting on postoperative outcomes. We hypothesized that longer waiting times are detrimental to achieving the full benefit of surgery. We prospectively examined 201 patients with osteoarthritis who were on the waiting list for primary total hip arthroplasties. The Western Ontario and McMaster Universities Osteoarthritis Index questionnaire was used to assess patients at surgical consultation (preoperative) and 1 year postoperative. The study included regression models to determine the expected outcome for an individual's preoperative score. Logistic regression models were used to assess the relationship between waiting time and the probability of a better than expected outcome. We found that the odds of achieving a better than expected postoperative functional outcome decreased by 8% for each month on the waiting list. Expedited access resulted in a larger proportion of patients with better than expected function 12 months after surgery.

Adult↗

PubMed2006

Hyperglycaemia after glucose loading is a major predictor of preclinical atherosclerosis in nondiabetic subjects.

OBJECTIVE: Carotid intima-media thickness (IMT) has proved to be an independent marker of preclinical atherosclerosis. The aim of this study was to determine whether carotid IMT is associated with the plasma glucose concentration in the fasting state, after loading with oral glucose, or with the insulin sensitivity index (ISI) in nondiabetic subjects with different levels of glucose intolerance and insulin resistance. DESIGN: Cross-sectional study. PATIENTS: A total of 160 nondiabetic subjects (147 from our obesity-overweight clinic and 13 healthy normal subjects) were included in the present study, among them 33 had normal glucose tolerance (NGT), 13 had impaired fasting glucose (IFG), 80 had impaired glucose tolerance (IGT) and 34 had both IFG and IGT. MEASUREMENTS: Carotid IMT was assessed in the common carotid artery by a high-resolution B-mode ultrasound system. Plasma glucose was measured after fasting and at 30 min, 1, 2 and 3 h after a standard 75-g load of glucose. The ISI was calculated from the frequent sampling intravenous glucose tolerance test (FSIGT). Results The IMT values in the NGT group were lower than those in the IFG, IGT and IFG + IGT groups (P < 0.03). No statistical difference in IMT values was found among the latter three groups. Univariate correlation analyses showed that the IMT was positively associated with age, plasma glucose concentrations 1 and 2 h after glucose loading, and serum concentration of low density lipoprotein (LDL) cholesterol (r=0.39, 0.22, 0.25 and 0.18, respectively, P<0.05). Multiple regression analysis showed that only age, plasma glucose concentration 2 h after glucose loading, and LDL cholesterol appeared to be significant correlates of the IMT (P<0.0001), whereas the ISI was not. CONCLUSIONS: In nondiabetic subjects with various degrees of glucose intolerance, there was a significant increase in IMT in those with IFG and IGT. Significant determinants of IMT, an indicator of preclinical atherosclerosis, include hyperglycaemia 2 h after a glucose load, age and LDL cholesterol, whereas fasting glucose concentration and the ISI were not significantly associated with IMT.

Administration, Oral↗

PubMed2006

Genome scale analysis of diffusible signal factor regulon in Xanthomonas campestris pv. campestris: identification of novel cell-cell communication-dependent genes and functions.

The bacterial pathogen Xanthomonas campestris pv. campestris (Xcc) recruits a diffusible signal factor (DSF), which has recently been structurally characterized as cis-11-methyl-2-dodecenoic acid, as a cell-cell communication signal to synchronize virulence gene expression and biofilm dispersal. In this study, we showed that despite the existance of phenotype variations in different Xcc isolates, the DSF-mediated functions were in general conserved. To investigate the genomic profiles of DSF regulation, we designed and conducted oligomicroarray analysis by comparison of the gene expression patterns of wild-type strain XC1 and its DSF-deficient mutant XC1dF, as well as those of XC1dF in the presence or absence of DSF signals. The analyses led to identification of 165 genes, whose expression was significantly influenced by DSF signals. These genes encode proteins and enzymes belonging to at least 12 functional groups. In addition to those previously known DSF-dependent activities such as production of extracellular enzymes and extracellular polysaccharides, microarray analyses also revealed new functions mediated by DSF, such as flagellum synthesis, resistance to toxins and oxidative stress, and aerobic respiration. Phenotype analyses confirmed that DSF signalling contributed to resistance to toxin acriflavin and hydrogen peroxide, and to the survival of bacterial cells at different temperatures. We conclude that DSF cell-cell signalling is not only essential for co-ordinating the expression of virulence genes but also plays a vital role in keeping up the general competence of the pathogen in ecosystems.

Base Sequence↗