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C X Zhang

Publications and source records attributed to C X Zhang.

At least 19 recordsLinked to original sources
PubMed2007

Meta-analysis: the effect of supplementation with probiotics on eradication rates and adverse events during Helicobacter pylori eradication therapy.

BACKGROUND: Recent evidence found probiotics could inhibit Helicobacter pylori colonization from both in vitro and in vivo studies. AIM: To systematically evaluate whether adding probiotics to anti-H. pylori regimens could improve eradication rates and reduce side effects during anti-H. pylori treatment. METHODS: Eligible articles were identified by searches of electronic databases. We included all randomized trials comparing probiotics supplementation to placebo or no treatment during anti-H. pylori regimens. Statistical analysis was performed with Review Manager 4.2.8. Subanalysis/Sensitivity analysis was also performed. RESULTS: We identified 14 randomized trials (n = 1671). Pooled H. pylori eradication rates were 83.6% (95% CI = 80.5-86.7%) and 74.8% (95% CI = 71.1-78.5%) for patients with or without probiotics by intention-to-treat analysis, respectively, the odds ratio (OR) was 1.84 (95% CI = 1.34-2.54); the occurrence of total side effects were 24.7% (95% CI = 20.0-29.4%) and 38.5% (95% CI = 33.0-44.1%) for groups with or without probiotics, especially for diarrhoea, the summary OR was 0.44 (95% CI = 0.30-0.66). CONCLUSIONS: Our review suggests that supplementation with probiotics could be effective in increasing eradication rates of anti-H. pylori therapy, and could be considered helpful for patients with eradication failure. Furthermore, probiotics show a positive impact on H. pylori therapy-related side effects.

Anti-Bacterial Agents↗
PubMed2006

TL and OSL of SrSO4 phosphors doped with Eu.

The thermoluminescence (TL) and optically stimulated luminescence (OSL) of SrSO4:Eu (0.1 mol%) powder sample were studied. The TL and OSL emission spectrum are measured after irradiation (absorbed dose 100 Gy) of 90Sr source; both of them showed that the emission wavelength is at approximately 375 nm, which indicates that TL and OSL have the same luminescence centres, and the luminescence comes from transitions between the energy levels of Eu2+. The TL glow curves and OSL decay curves illustrate that there is only one main TL peak but two main components in OSL curves. By a comparative study of TL and OSL it is concluded that OSL traps are different from TL traps. The TL and OSL dose responses of SrSO4:Eu phosphor were measured, and it showed that phosphor has similar dose responses for OSL and TL.

Computer Simulation↗
PubMed2006

Thermoluminescence glow curves and optical stimulated luminescence of undoped alpha-Al2O3 crystals.

The characteristics of thermoluminescence (TL) and optical stimulated luminescence (OSL) in undoped alpha-Al2O3 single crystals were studied. The TL glow curves of the crystal samples irradiated at various dose levels were measured by RisØ TL/OSL-DA-15B/C reader with U-340 or 7-59 filters at different heating rates. The glow peaks measured with U-340 at approximately 210 degrees C of the undoped alpha-Al2O3 can be well fitted by first-order kinetic equation whereas the glow peaks measured with 7-59 filters are a composite of two first-order glow peaks. It indicates that the TL glow curves are dependent upon the filter used in the reader that is related to the emission spectra of luminescence materials. The OSL were also measured and fitted by two exponential functions to get the luminescence intensities. The TL and OSL dose responses of the undoped alpha-Al2O3 crystal were obtained in the dose range of 0.12-248 Gy and fitted by the composite action dose-response function to get nonlinear characteristic parameters. The TL and OSL dose responses are linear-sublinear.

Aluminum Oxide↗
PubMed2006

Defect complexes in Re3+-doped magnesium sulphate phosphors.

A series of magnesium sulphate phosphors MgSO4:RE3+,X ( RE = Dy, Tm, Eu and X = P, Mn) have been prepared and studied. Based on the experimental results of thermoluminescence (TL) emission spectra and dose responses studies, it is proposed that in these phosphors large defect complexes are formed, which include intrinsic imperfections and dopants. These defect complexes were formed in the course of preparation of phosphors and could be regarded as basic elements in the TL multi-stage processes. This defect model might be applicable to the most of TL materials.

Artifacts↗
PubMed2005

[Genetics of endocrine tumours].

Major advances have been made in the understanding of the genetic mechanisms underlying endocrine tumorigenesis, through the study of several syndromes of genetic predisposition and the identification of the genes involved. The syndrome of type 1 multiple endocrine neoplasia (MEN-1) is one of the best known; this autosomal dominant hereditary syndrome predisposes to the development of endocrine tumors of the pituitary, the parathyroids, the foregut and the adrenals. The responsible gene, known as MEN-1, encodes an original protein, menin, involved in several major cellular functions, such as the control of cell proliferation and differentiation. Type 2 multiple endocrine neoplasia (MEN-2) is an autosomal dominant hereditary syndrome associated with the development of medullary carcinomas of the thyroid, pheochromocytomas and hyperparathyroidism; the corresponding gene, RET, encodes a transmembrane receptor with tyrosine kinase activity. Endocrine tumors are also associated with non Hippel-Lindau disease and with phacomatoses, such as type 1 neurofibromatosis and tuberous sclerosis. Finally, isolated familial syndromes of endocrine tumors have been described: isolated familial hyperparathyroidism type II (HRPT2), associated with alterations in a gene coding for an original protein, parafibromin, or isolated familial syndromes of pheochromocytomas and paragangliomas (PRG) associated with mutations in the genes SDHB, SDHC or SDHD, which encode succinate-dehydrogenase subunits. The understanding of the genetic mechanisms underlying these syndromes of predisposition is essential for the diagnosis and management of these patients and their family; it also gives insight on the molecular mechanisms of endocrine tumorigenesis.

Adrenal Gland Neoplasms↗
PubMed2004

Aquabirnaviruses isolated from marine organisms form a distinct genogroup from other aquabirnaviruses.

A phylogenetic tree of aquabirnaviruses, including marine birnaviruses (MABV) and infectious pancreatic necrosis virus (IPNV), was developed based on the nucleotide sequences and deduced amino acid sequences of the polyprotein and VP5 genes of genomic segment A. In the polyprotein of MABV strains, the amino acid sequences were very similar, with identities of 98.3-99.7%. Twenty-one unique amino acid residues were found in the deduced amino acid sequences of the polyprotein gene of MABV strains. The phylogenetic tree based on the nucleotide sequence of genomic segment A and polyprotein sequences showed that 31 aquabirnavirus strains were clustered into seven genogroups. All MABV strains isolated in Japan and Korea were clustered into one genogroup which was distinct from other aquabirnaviruses. The seventh genogroup containing all MABV strains showed amino acid sequence similarities of 80.7-90.6% with other genogroups. In VP5, four unique residues were found in MABV strains when compared with IPNV strains. The MABV strains exhibited amino acid sequence similarities of 63.9-86.4% with IPNV strains. The amino acid sequences of VP5 were conserved among MABV strains, but differed from those of IPNV strains. The MABV strains isolated from different host species and different geographical areas were very similar to each other, suggesting that the MABV are distinct from the other genogroups.

Amino Acid Sequence↗
PubMed2003

Comparison of the RNA polymerase genes of marine birnavirus strains and other birnaviruses.

The cDNA nucleotide sequence of the genome segment B encoding the VP1 protein, the putative RNA-dependent RNA polymerase (RdRp), was determined for 5 marine birnavirus (MABV) strains from different host or geographic origins and 1 infectious pancreatic necrosis virus (IPNV) strain AM-98. Segment B of the IPNV AM-98 strain and 4 MABV strains, Y-6, YT-01A, H1 and NC1, contained a 2535 bp ORF, which encoded a protein of 845 amino acid residues with a predicted MW of 94.4 kDa. Only the MABV AY-98 RdRp had 1 amino acid shorter RdRp. Pairwise comparisons were made among our data and 4 other known IPNV sequences. The nucleotide sequences of the 5 MABV strains were very similar each other, with identities of 98.3-99.7%. The highest divergence of the nucleotide level was between MABV strains and IPNV SP strain (serotype A2), with 20.4-20.8% divergences in the coding region, which gave 10.1-11.3% divergence in the amino acid level. The aquabirnavirus RdRp was noticeably conserved in amino acid sequences. Though the identities of the nucleotide sequences of encoding region were 85.1-85.9% between MABV strains and IPNV serotype A1 strains, they shared as high as 95.1-95.9% identities in amino acid level. A phylogenetic tree was constructed based on the amino acid sequences of the RdRp gene from different birnaviruses including avibirnavirus and entomobirnavirus. Ten aquabirnavirus strains were clustered into 3 Genogroups. The Genogroup I consisted of four IPNV A1 serotype strains. All MABV strains were clustered into Genogroup II. Only IPNV SP strain was clustered into an independent Genogroup III.

Amino Acid Sequence↗
PubMed2002

Non-linearity of TL dose responses in MgSO4:Dy CO-doped with Mn, P and Cu.

Thermoluminescence (TL) dose responses to gamma radiation in the dose range from 0.1 Gy to 20 kGy in MgSO4:Dy, MgSO4:Dy,Mn, MgSO4:Dy,P and MgSO4:Dy,P,Cu phosphors were obtained and fitted by the composite action dose response function to obtain non-linear characteristic parameters, one-hit factor R and characteristic dose D0, which indicate that the TL dose responses for individual TL glow peaks in MgSO4:Dy, MgSO4:Dy,Mn and MgSO4:Dy,P phosphors all are supralinear. The non-linearity of dose response for the main dosimetric peak in MgSO4:Dy,P,Cu depends critically on the concentration of doped Cu and sublinearity can be obtained in the dose responses of TL materials doped with a certain amount of Cu. Based on studying the TL glow curves, dose responses and three dimension emission spectra of these phosphors, it is supposed that the TL event is generated via a multi-stage process within a large defect complex in doped magnesium sulphate phosphors. Doping with Cu results in reformation of the defect complex in which there is a strong spatial association between a trapping centre and a recombination centre so that the probability of one-hit TL events increases. The non-linearity of the dose responses is usually a difficulty for measuring higher dose in TL dosemeters. It can be overcome by enlarging the linear range of the dose-response or by calibrating the dose-response curves using non-linear characteristic parameters in a dose response function, such as the composite action dose response function.

Copper↗
PubMed2002

Thermoluminescence of MgSO4 doped with Eu and P impurities.

CaSO4:Eu, MgSO4:Eu and MgSO4:Eu,P phosphors have been prepared and their thermoluminescence (TL) characteristics were studied. A main glow peak due to Eu2+ ions is seen at approximately 146 degrees C and 440 nm and glow peaks at approximately 145 degrees C, approximately 190 degrees C, approximately 260 degrees C and approximately 360 degrees C for 590 nm and 625 nm wavelengths are identified as Eu3+ ion emissions in MgSO4:Eu. Emission spectra in MgSO4:Eu and the MgSO4:Eu,P show that the MgSO4:Eu3+ glow peak at 260 degrees C for 590 nm and 625 nm shifts to 280 degrees C with enhanced intensity while the Eu2+ ion glow peak at 146 degrees C remains but with reduced intensity. The main glow peak at approximately 146 degrees C and 440 nm from Eu2+ ions shows significant difference from the characteristic glow peaks of Eu3+ ions. It is observed that the wavelength of the Eu2+ ion glow peak is inversely proportional to the radius of the cation of the host sulphate in alkaline-earth sulphate phosphors. By contrast the wavelengths of the Eu3+ ion glow peaks remain unchanged in different sulphates. Besides, the glow curve at approximately 146 degrees C obtained using a conventional blue sensitive reader shows simply the first order kinetics. It is concluded that the luminescence centres and distribution of traps related to Eu2+ ions are different from that of Eu3+ ions in MgSO4:Eu and MgSO4:Eu,P phosphors.

Europium↗
PubMed2001

Narrow sample channel injectors for capillary electrophoresis on microchips.

In microchip CE, sample injection is generally achieved through cross, double-tee, or tee injector structures. In these reported approaches, channel width and depth are uniform at the injection intersection. Here, we present cross and tee injectors having narrow sample channels. Using a cross injector with reduced sample channel width, resolution, column efficiency, and sensitivity are remarkably improved. Furthermore, no leakage control is required in both injection and separation phases, making the microchip CE system more user-friendly. Good resolution can also be obtained using tee injectors with narrow sample channels, which would otherwise be impossible using conventional tee injectors. Using the narrow sample channel tee injector instead of conventional cross and double-tee injectors, the number of reservoirs in multiplexed systems can be reduced to N + 2 (N, the number of paralleled CE systems), the real theoretical limit. The virtues of the novel injectors were demonstrated with poly(dimethylsiloxane)-glass chips incorporating eight parallel CE channels.

Journal Article↗
PubMed2001

Effect of human oviductal epithelial cell cultural medium on cryopreserved human sperm survival.

The human oviduct is known as a functional site for gamete transportation, retention, fertilization and zygote development. Previous studies have shown that human oviductal epithelial cell cultural medium (OECCM) has a positive effect on prolongation of sperm motility for some cryopreserved human sperm without cryodamage. However, for most cryopreserved sperm, OECCM could not improve their survival prolongation. In this study, we assessed the influence of human OECCM on the motility longevity of cryopreserved human sperm with an in vitro incubation method.

Cell Survival↗
PubMed2000

Essential functions of DNA topoisomerase I in Drosophila melanogaster.

DNA topoisomerase I (topo I) is an essential enzyme involved in replication, transcription, and recombination. To probe the functions of topo I during Drosophila development, we used top1-deficient flies with heat-shock-inducible top1 transgenes and were able to observe both zygotic and maternal functions of top1. A critical period for the zygotic function is in the late larval and early pupal stages. Topo I is required for larval growth and cell proliferation in imaginal disc tissues. The maternal functions consist of two aspects: oogenesis and early embryogenesis. During oogenesis, topo I is detected in the nuclei of early germ-line cells and follicle cells. The mutant ovary exhibits abnormal proliferation and defective nuclear morphology in these cells. There are extranumeral germ-line cells in individual egg chambers, while the follicle cells are underreplicated. Topo I is also stored maternally in early embryos. It localizes to the nuclei during interphase and prophase, but disperses into the cytoplasm at metaphase. Embryos from the mutant mother frequently show disrupted nuclear divisions with defects in chromosome condensation and segregation. The cytological and genetic analysis of the top1 mutant demonstrates that in Drosophila, topo I plays critical roles in many developmental stages active in cell proliferation.

Animals↗
PubMed2000

Stepwise mobilization of focused proteins in capillary isoelectric focusing mass spectrometry.

A stepwise mobilization strategy has been developed for the elution of complex protein mixtures, separated by capillary isoelectric focusing (CIEF) for detection using on-line electrospray ionization mass spectrometry (ESI-MS). Carrier polyampholytes are used to establish a pH gradient as well as to control the electroosmotic flow arising from the use of uncoated fused-silica capillaries. Elution of focused protein zones is achieved by controlling the mobilization pressure and voltage, leaving the remaining protein zones focused inside the capillary. Protein zones are stepwise eluted from the capillary by changing the mobilization conditions. Stepwise mobilization improves separation resolution and simplifies coupling with multistage MS (i.e., MSn) analysis since it allows more effective temporal control of protein elution from the CIEF capillary. We also describe a modified configuration for coupling CIEF with ESI-MS using a coaxial sheath flow interface that facilitate the automation of on-line CIEF-ESI-MS analyses. The stepwise mobilization strategy is demonstrated for the analysis of standard protein mixtures and soluble E. coli lysate proteins using CIEF-ESI-MS. These results indicate that inlet pressure or voltage programming to control the elution of the protein zones from the capillary (i.e., gradient mobilization) may allow for the optimization of the mobilization conditions and provide higher resolution for CIEF separation of complex mixtures with on-line MS.

Electrophoresis, Capillary↗
PubMed2000

Expression analysis of endogenous menin, the product of the multiple endocrine neoplasia type 1 gene, in cell lines and human tissues.

We have investigated the endogenous expression of menin, a protein encoded by the gene mutated in multiple endocrine neoplasia type 1 (MEN1). Western blot analysis showed strong expression of menin as a 68 kDa protein in all of 7 human and primate cell lines tested. In a panel of 12 fetal human tissue extracts, 68 kDa menin was readily detected in brain cortex, kidney, pituitary, testis and thymus and weakly detected in thyroid. Reproducible bands other than 68 kDa were observed in adrenal and heart, whereas menin was undetectable in liver, lung, pancreas and skin. Analysis of synchronized HeLa cells revealed no variation in the amount or size of menin throughout the cell cycle. Protein expression was compared between lymphoblastoid cell lines from healthy controls and MEN1 patients carrying nonsense mutations on 1 allele. No truncated protein was detected in either cytoplasmic or nuclear fractions in mutation-carrying cells. The expression level and cellular location of full-length menin did not differ between cell lines derived from MEN1 patients and healthy donors. This suggests that the wild-type allele has been up-regulated in mutation-carrying cells to compensate for the loss of 1 functional allele.

Animals↗
PubMed2000

Discontinuous actin hexagon, a protein essential for cortical furrow formation in Drosophila, is membrane associated and hyperphosphorylated.

discontinuous actin hexagon (dah) is a maternal-effect gene essential for the formation of cortical furrows during Drosophila embryogenesis, and DAH protein colocalizes with actin in these furrows. Biochemical fractionation experiments presented here demonstrate that DAH is highly enriched in the membrane fraction and that its membrane association is resistant to high-salt and alkaline washes. Furthermore, it partitions into the detergent phase of the Triton X-114 solution, indicating its tight binding to the membranes. DAH can also interact with the actin cytoskeleton, because a fraction of DAH remains insoluble to nonionic detergent along with actin. These biochemical characterizations suggest that DAH may play a role in the linkage of the actin cytoskeleton to membranes. Using phosphatase inhibitors, we detected multiple phosphorylated forms of DAH in embryonic extracts. The DAH phosphorylation peaks during cellularization, a stage at which DAH function is critical. A kinase activity is coimmunoprecipitated with the DAH complex and hyperphosphorylates DAH in vitro. Purified casein kinase I can also hyperphosphorylate DAH in the immune complex. Both DAH localization and phosphorylation are disrupted in another maternal-effect mutant, nuclear-fallout. It is possible that nuclear-fallout collaborates with dah and directs DAH protein localization to the cortical furrows.

Animals↗
PubMed2000

[High expression of human EPO gene in the larvae and pupae of the silkworm, Bombyx mori].

Erythropoietin (EPO) is a glycoprotein hormone produced primarily by the kidney, and is principal factor regulating red blood cell poduction. The synthesized EPO cDNA was inserted into the transfer vector pBlueBac III to generate the recombinant transfer plasmid pBlueBacEPO. Cotransfection of BmN cells with pBlueBacEPO DNA and Wild BmNPV DNA generated the recombinant virus rBmNPVEPO carrying EPO gene driven by the strong promoter of AcNPV polyhedrin gene. The results of Southern blot and PCR reaction confirmed that EPO gene had been correctly inserted in the target position in the BmNPV genome. ELISA assay showed that the EPO gene was expressed with high level in the larvae and pupae of the silkworm. The larvae and pupae produced as high as 62,800 u and 74,000 u in 1 mL hemolymph on the 4th day (larve) and the 5th day(pupae) after infection with the recombinant virus rBmNPVEPO, respectively. Western blot analysis showed the molecular weight of rhEPO produced in the lavae or pupae was about 26 kD. Biologic assay showed the rhEPO had high activity (about 63,000 u in per milliliter of hemolymph) in vitro.

Animals↗