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Biomedical subjects

Wei Hu

Publications and source records attributed to Wei Hu.

At least 55 records · Page 3Linked to original sources
PubMed2006

[Prediction human daily boron exposure by urine boron concentration].

Relationship between post-shift boron concentration and daily boron exposure was analyzed with the workers from boron mining and processing plants in Liaoning Province and population from sanitary background area far from boron industry as subjects. The results demonstrate that there was significant logarithm linearity correlativity between post-shift urine boron concentration and daily boron exposure, and the fittingness of the regression equation was up to 85.9% by considering of the effect of the different group of population, and the equation predicting daily boron exposure by post-shift urine boron concentration was determined. Daily boron exposures of the subjects in 2004 were predicted using this equation. Comparing of the daily boron exposure observed, the average of deviation between the boron exposures predicted and observed was 13.4%, and there was no significant difference between the exposure value predicted and observed. Therefore, it is feasible to predict daily boron exposure by boron concentration of post-shift urine. The analyzing of predicted daily boron exposure of all subjects in 2004 show that the daily boron exposure of peoples from occupational exposure group, community group and background control group were respectively 36.1, 4.13 and 1.31mg/d.

Adult↗
PubMed2006

[Protective effect of octreotide on liver warm ischemia reperfusion injury].

OBJECTIVE: To explore the protective effect of octreotide on liver warm ischemia-reperfusion injury and its possible mechanism. METHODS: Pringle's maneuver liver ischemia-reperfusion models were established. Forty eight male Sprague Daweley rats were randomly divided into a sham operation group (S group, n=16), an ischemia-reperfusion group (I/R group, n=16) and an octreotide preconditioning group (OPC group, n=16). ALT and AST in the serum were measured at 30 min after the ischemia and 120 min after the reperfusion. The histomorphological changes and ultrastructure of hepatocellular were observed by optic and transmission electronic microscope. Hepatic adenine nucleotide levels and energy changes (EC) were determined by high performance liquid chromatography (HPLC). RESULTS: (1) At 30 min after the ischemia and 120 min after the reperfusion, the levels of ALT and AST in the serum of OPC group was lower than those in I/R group, whereas the levels of ATP and EC in the hepatic tissue were higher than those in the I/R group (P<0.01 or P<0.05). Compared with the I/R group, the injury of hepatocellular histomorphology and ultrastructure in the OPC group was abated. (2) At 30, 60, and 120 min after the reperfusion, the levels of ATP and EC in the OPC groups were higher than those in the I/R group. During the ischemia, the levels of ATP and EC in the OPC group dropped more slowly than those in the I/R group, but ATP and EC in the OPC groups rose more quickly than those in the I/R group during the reperfusion. CONCLUSION: Octreotide precondition can improve the hepatocellular energy reserve, and protect the liver from warm ischemia-reperfusion injury. The protective of octreotide on warm ischemia-reperfusion injury may be related to its influence on endocrine secretion.

Animals↗
PubMed2006

[Effect of high volume hemofiltration on respiration, hemodynamics and oxygen metabolism in sepsis with acute respiratory distress syndrome].

OBJECTIVE: To investigate the effect of continuous high volume hemofiltration (HVHF) on respiration, hemodynamics, and oxygen metabolism in severe sepsis patients with acute respiratory distress syndrome (ARDS). METHODS: Twelve adult patients with ARDS received mechanical ventilation and HVHF (80 mlxkg(-1)xh(-1)) lasting 12-18 hours every day. The cardiac output (CO), systemic vascular resistance (SVR), pulmonary vascular resistance (PVR), mean pulmonary arterial pressure (MPAP), pulmonary artery wedge pressure (PAWP), arterial oxygen content (CaO(2)), O(2) content of mixed venous blood (CvO(2)), oxygen consumption (VO(2)), oxygen delivery (DO(2)) and oxygen extraction rate (O(2)ER) were measured with the aid of a Swan-Ganz catheter, the thoracic fluid content (TFC) were measured with BioZ(r) Cardio Dynamics. Concentrations of tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), IL-8 and IL-10 were measured pre-continuous HVHF and after continuous HVHF by enzyme linked immunoadsorbent assay (ELISA). Acute physiology and chronic health evaluation II (APACHEII) scores, multiple organ dysfunction syndrome (MODS) evaluation scores and PaO(2)/FiO(2) were observed before and after HVHF. RESULTS: There were significant lowering of concentrations of TNF-alpha, IL-6 and IL-8 after HVHF at 72 hours (all P<0.05), and also in MPAP, PVR and TFC after 48 hours (all P<0.05). DO(2), VO(2) and O(2)ER were stabilized at 72 hours with amelioration of partial pressure of oxygen in artery (PaO(2)), PaO(2)/FiO(2) and peak airway pressure (Ppeak) (P<0.05 or P<0.01). CONCLUSION: Continuous HVHF shows significant beneficial effects on pulmonary function of severe sepsis patients with ARDS as a result of removal of cytokines, decrease of TFC and amelioration of disturbance in respiration, hemodynamics and oxygen metabolism.

Adult↗
PubMed2005

Occurrence of endocrine-disrupting compounds in reclaimed water from Tianjin, China.

Continuous disposal of endocrine-disrupting compounds (EDCs) into the environment can lead to serious human health problems and can affect plants and aquatic organisms. The determination of EDCs in water has become an increasingly important activity due to our increased knowledge about their toxicities, even at low concentration. The EDCs in water samples from the reclaimed water plant of Tianjin, northern China, were identified by gas chromatography (GC)-mass spectrometry (MS). Important and contrasting EDCs including estrone (E1), 17beta-estradiol (E2), 17alpha-ethynylestradiol (EE2), 4-tert-octylphenol (OP), 4-nonylphenol (NP), bisphenol A (BPA), di-n-butyl phthalate (DnBP), diisobutyl phthalate (DIBP), and di(2-ethylhexyl)phthalate (DEHP) were selected as the target compounds. Concentrations of steroid hormones, alkylphenolic compounds and phthalates ranged from below the limit of detection (LOD) to 8.1 ng L(-1), from <LOD to 14.2 ng L(-1), and from 1.00 microg L(-1) to 23.8 microg L(-1), respectively. The average removal efficiencies for target EDCs varied from 30% to 82%. These results indicate that environmental endocrine disrupting compounds are not completely removed during reclaimed water treatment and may be carried over into the general aquatic environment.

Algorithms↗
PubMed2005

Cervical chromosome 9 polysomy: validation and use as a surrogate endpoint biomarker in a 4-HPR chemoprevention trial.

BACKGROUND: Several genetic alterations have been described in cervical cancers including: human papillomavirus (HPV) E6 and E7 oncoproteins, subtle sequence changes, alterations in chromosome number, chromosome translocations, and gene amplifications. This report focuses on establishing chromosome 9 polysomy as a cervical biomarker of chromosome instability and using it in a chemoprevention trial. Chromosomal instability is a feature of most human cancers and is probably an early event in the process. METHODS: We used 37 cervical cone specimens to validate chromosome 9 polysomy as a biomarker and then tested its modulation in a randomized clinical trial of 4-hydroxyphenylretinamide (4-HPR) in 39 patients with three blinded histopathologic reviews. No confounders were identified. In the present study, immunohistocytochemical analysis of Chromosome 9 polysomy was carried out and quantitatively measured. RESULTS: The Cell Index, the ratio of the number of total chromosome 9 copies to the total number of ells, increases significantly in archival samples as the cervix changes from normal to CIN to invasive cancer. In the chemoprevention trial, chromosome 9 polysomy was used as a biomarker and supported the histological analysis showing that 4-HPR impaired the natural regression response. CONCLUSIONS: Chromosome 9 polysomy appears to be a marker of genetic instability that can be used in chemoprevention trials as a surrogate endpoint biomarker. In this randomized trial of 4-HPR, the chromosome 9 polysomy measurements supported the clinical histopathologic reading in a quantitative manner suggesting that 4-HPR at 200 mg/day may have been inhibiting the regression seen in the placebo arm by inducing genetic instability.

Aneuploidy↗
PubMed2005

Kinetic properties of nuclear transport conferred by the retinoblastoma (Rb) NLS.

The retinoblastoma (RB) tumor suppressor is a nuclear phosphoprotein central to control of cellular proliferation. We have previously shown that human RB possesses an evolutionarily conserved bipartite nuclear localization sequence (NLS) (KRSAEGSNPPKPLKKLR877) resembling that of nucleoplasmin. Here we analyze the kinetic properties of the RB NLS in detail with respect to recognition by cellular nuclear import factors, the importins (IMPs), and nuclear transport properties, comparing results to those for the NLSs from SV40 large tumor antigen (T-ag) and the Xenopus laevis phosphoprotein N1N2. Binding affinities of different IMPalpha subunits for the Rb NLS, in the absence or presence of IMPbeta subunits were determined, and NLS-dependent nuclear import reconstituted in vitro for the first time using purified IMPalpha/beta subunits together with recombinant human RanGDP and nuclear transport factor 2 (NTF2). RB NLS-mediated transport had a strict requirement for all components, with high NTF2 concentrations inhibiting transport. As in the case of transport mediated by the T-ag- and N1N2-NLSs, nuclear import of an RB-NLS containing beta-Gal fusion protein was reduced or abolished when anti-IMPalpha or beta antibody was added to cytosolic extract, respectively, confirming that RB NLS-mediated nuclear import occurs through action of IMPalpha/beta. We conclude that although mediated by IMPalpha/beta, and similar in most respects to transport mediated by the similarly bipartite N1N2 NLS, nuclear import conferred by the RB NLS has distinct properties, in part due to the affinity of its interaction with IMPalpha.

Active Transport, Cell Nucleus↗
PubMed2005

Interaction of the nuclear localizing cytolytic granule serine protease granzyme B with importin alpha or beta: modulation by the serpin inhibitor PI-9.

Conditional on perforin-dependent delivery to the nucleus of target cells, the cytolytic granule serine protease granzyme B (GrB) plays a central role in eliciting the nuclear events of apoptosis, as shown by the fact that reducing GrB nuclear entry prevents nuclear apoptosis. Apart from a requirement for cytosolic factors and lack of dependence on the guanine-nucleotide-binding protein Ran, little is known regarding the nuclear import pathway of GrB. In this study we use quantitative yeast two-hybrid and direct binding assays to show that GrB can be recognized independently by either of the nuclear import receptor family members importin (IMP) alpha and beta1, but that these proteins either alone or in combination cannot replace exogenous cytosol to reconstitute GrB nuclear import in vitro. Whereas antibodies to IMP(alpha) inhibit transport, indicating that IMP(alpha) is required for GrB nuclear import, those to IMP(beta) enhance transport, implying that IMP(beta) inhibits GrB nuclear import; consistent with this, the addition of recombinant IMP(beta) but not IMP(alpha) reduces maximal nuclear accumulation in the presence of cytosol. Intriguingly, complexation of GrB with its specific serpin inhibitor PI-9 was found to prevent recognition by IMP(beta) but not by IMP(alpha), and eliminate the apparent requirement for IMP(alpha) for nuclear import. We conclude that GrB nuclear import exhibits complex regulation by IMPs; that heterodimerization with PI-9 can modulate the interaction has implications for protection against apoptosis.

Active Transport, Cell Nucleus↗
PubMed2005

The Genomes of Oryza sativa: a history of duplications.

We report improved whole-genome shotgun sequences for the genomes of indica and japonica rice, both with multimegabase contiguity, or almost 1,000-fold improvement over the drafts of 2002. Tested against a nonredundant collection of 19,079 full-length cDNAs, 97.7% of the genes are aligned, without fragmentation, to the mapped super-scaffolds of one or the other genome. We introduce a gene identification procedure for plants that does not rely on similarity to known genes to remove erroneous predictions resulting from transposable elements. Using the available EST data to adjust for residual errors in the predictions, the estimated gene count is at least 38,000-40,000. Only 2%-3% of the genes are unique to any one subspecies, comparable to the amount of sequence that might still be missing. Despite this lack of variation in gene content, there is enormous variation in the intergenic regions. At least a quarter of the two sequences could not be aligned, and where they could be aligned, single nucleotide polymorphism (SNP) rates varied from as little as 3.0 SNP/kb in the coding regions to 27.6 SNP/kb in the transposable elements. A more inclusive new approach for analyzing duplication history is introduced here. It reveals an ancient whole-genome duplication, a recent segmental duplication on Chromosomes 11 and 12, and massive ongoing individual gene duplications. We find 18 distinct pairs of duplicated segments that cover 65.7% of the genome; 17 of these pairs date back to a common time before the divergence of the grasses. More important, ongoing individual gene duplications provide a never-ending source of raw material for gene genesis and are major contributors to the differences between members of the grass family.

Base Sequence↗
PubMed2005

Golgi fragmentation is associated with ceramide-induced cellular effects.

Ceramide has been shown to cause anoikis, a subtype of apoptosis due to inadequate cell adhesion. However, the underlying mechanism is unclear. Herein, we report that D-e-C6-ceramide (D-e-Cer), via generating sphingosine, disrupts the Golgi complex (GC), which is associated with various cellular effects, including anoikis. Treatment of HeLa cells with D-e-Cer caused cell elongation, spreading inhibition, rounding, and detachment before apoptosis (anoikis). In D-e-Cer-treated cells, glycosylation of beta1 integrin in the GC was inhibited, thus its associated integrin receptors failed to translocate to the cell surface. Ceramide treatment also inhibited the reorganization of both microtubule and F-actin cytoskeletons, focal adhesions, and filopodia. These cellular effects were preceded by fragmentation of the Golgi complex. In contrast, L-e-C6-ceramide (L-e-Cer), the enantiomer of D-e-Cer, failed to induce these cellular effects. Mass spectrometric analysis revealed that treatment HeLa cells with D-e-Cer but not L-e-Cer caused a >50-fold increase in the levels of sphingosine, a product of hydrolysis of ceramide. Treatment with D-e-sphingosine and its enantiomer, L-e-sphingosine, caused massive perinuclear vacuolization, Golgi fragmentation, and cell rounding. Together, these results suggest that sphingosine generated from hydrolysis of ceramide causes the GC disruption, leading to various cellular effects.

Actins↗
PubMed2005

Peritoneal and subperitoneal stroma may facilitate regional spread of ovarian cancer.

PURPOSE: Epithelial ovarian cancer (EOC) is characterized by early peritoneal involvement ultimately contributing to morbidity and mortality. To study the role of the peritoneum in fostering tumor invasion, we analyzed differences between the transcriptional repertoires of peritoneal tissue lacking detectable cancer in patients with EOC versus benign gynecologic disease. EXPERIMENTAL DESIGN: Specimens were collected at laparotomy from patients with benign disease (b) or malignant (m) ovarian pathology and comprised primary ovarian tumors, paired bilateral specimens from adjacent peritoneum and attached stroma (PE), subjacent stroma (ST), peritoneal washes, ascites, and peripheral blood mononuclear cells. Specimens were immediately frozen. RNA was amplified by in vitro transcription and cohybridized with reference RNA to a custom-made 17.5k cDNA microarray. RESULTS: Principal component analysis and unsupervised clustering did not segregate specimens from patients with benign or malignant pathology. Class comparison identified differences between benign and malignant PE and ST specimens deemed significant by permutation test (P = 0.027 and 0.012, respectively). A two-tailed Student's t test identified 402 (bPE versus mPE) and 663 (mST versus bST) genes differentially expressed at a significance level of P2 < or = 0.005 when all available paired samples from each patient were analyzed. The same comparison using one sample per patient reduced the pool of differentially expressed genes but retained permutation test significance for bST versus mST (P = 0.031) and borderline significance for bPE versus mPE (P = 0.056) differences. CONCLUSIONS: The presence of EOC may foster peritoneal implantation and growth of cancer cells by inducing factors that may represent molecular targets for disease control.

Computational Biology↗
PubMed2005

Prevention of enamel demineralization: an in-vitro study using light-cured filled sealant.

INTRODUCTION: Enamel demineralization is an undesirable side effect of orthodontic treatment with fixed appliances. The purpose of this in-vitro study was to evaluate the efficacy of applying a light-cured filled sealant onto the buccal tooth surfaces to prevent demineralization. METHODS: Fifty extracted human third molars were allocated to 1 of 5 groups: (1) enamel surface untreated (control); (2) surface etched; (3) fluoride varnish applied; (4) enamel etched and coated with a light-cured, unfilled sealant (control sealant); and (5) enamel etched and coated with a light-cured, filled sealant (Pro Seal, Reliance Orthodontic Products, Itasca, Ill). The enamel surface of each specimen was brushed for 15,000 strokes with nonfluoride toothpaste slurry with a piston-action brushing machine under a standardized load. All samples were then cycled for 14 days through a daily procedure of demineralization for 6 hours and remineralization for 17 hours. Then the teeth were sectioned and evaluated quantitatively by cross-sectional microhardness testing. RESULTS: Demineralization in the Pro Seal group was significantly less (P < .05) than in the other groups. Teeth treated with fluoride varnish exhibited 30% less demineralization than the control teeth, the enamel-etched teeth, and the teeth treated with a light-cured, unfilled sealant (P < .05). CONCLUSIONS: Pro Seal can be considered for use as a preventive method to reduce enamel demineralization adjacent to orthodontic attachments, particularly in patients who exhibit poor compliance with oral hygiene and home fluoride use.

Analysis of Variance↗
PubMed2005

PTX cruiser: driving autoimmunity via TLR4.

Although the cause of autoimmune diseases is unknown, it has long been speculated that an infectious agent might have a role in their initiation and progression. Experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS), has been used to study factors in disease pathogenesis. A recent study shows that pertussis toxin, which is used as an adjuvant in EAE, uses Toll-like receptor 4 signaling to mediate its disease-inducing effect.

Animals↗
PubMed2005

Unambiguously distinguishing Si[3Si,1Al] and Si[3Si,1OH] stuctural units in zeolite by 1H/29Si/27Al triple resonance solid state NMR spectroscopy.

We present an experimentally feasible triple-resonance NMR method that establishes the correlation among three different nuclei, avoiding the difficulty to directly explore the weak coupling between two NMR nuclei, such as (29)Si and (27)Al. Using this method, we are able to give an unambiguous assignment to the various peaks in (29)Si CP NMR spectrum of MCM-22 zeolite and discriminate (29)Si signals from SiOHAl and SiOH groups. In addition, in combination with (1)H/(27)Al double-resonance technique, the (1)H/(27)Al/(29)Si triple-resonance experiment suggests the presence of two different kinds of Brönsted acid sites in H-MCM-22 zeolite.

Journal Article↗
PubMed2005

Identification and characterization of engrafted human cells in human/goat xenogeneic transplantation chimerism.

We have injected human CD34+lin- cells derived from cord blood (CB) into the goat fetuses via in utero at 45-55 days gestation under guidance of B-scan ultrasonograph. Sixty out of 68 fetuses injected survived to full term. The long-term survival of the human cells in transplant goat has been tested by various experimental methods, including FACS analysis, real-time PCR, RT-PCR, Southern-blot hybridization, FISH, as well as immunohistochemical assays. All the 60 transplant goats demonstrated engrafted human cells, including myeloid, B-lymphoid, and erythroid lineages. The yield of the human CD34+ cells varied, but was not linked with sex and age. High numbers of human cells could be detected for at least 16 months after birth. Immunohistochemical analyses revealed that the human cells were present not only in blood but also in other tissues, such as liver, of the transplant goats. In addition, a human-specific serum albumin and the hepatocyte nuclear factor (hHNF-3beta) mRNAs specific to human hepato-antigen could be readily detected in the livers of the transplant goats. Our results demonstrate that this in utero xenograft model should be useful for expansion of human HSC and possibly for the evaluating the effectiveness of prenatal treatment of human genetic diseases.

Animals↗
PubMed2005

Ginkgo biloba extract alleviates liver fibrosis induced by CCl in rats.

AIMS: To investigate the protective effect of Ginkgo biloba extract (GbE) on liver fibrosis induced by carbon tetrachloride (CCl4) in rats and expressions of transforming growth factor beta1 (TGF-beta1) and collagen I during this period. METHODS: The effect of GbE on liver fibrogenesis was detected by hematoxylin and eosin staining (H&E staining), Masson's trichrome staining, and electron microscope study. Blood samples were collected for measurement of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and albumin. Malondialdehyde (MDA) in liver tissue was detected by the thiobarbituric acid (TBA) method. Immunohistochemistry assay and RT-PCR were used to examine the protein expressions and mRNA levels of TGF-beta1 and collagen I, respectively. RESULTS: H&E, Masson's trichrome stainings and electron microscope study showed liver fibrosis in rats was greatly alleviated when treated with GbE. Additionally, there was a remarkable improvement of serum ALT, AST, albumin and MDA in the GbE-treated group. Immunohistochemistry and RT-PCR results showed GbE intervention significantly inhibited TGF-beta1 and collagen I expressions in rat liver. No side effects of GbE were found during these experiments. But GbE could not reverse the pathological changes of liver fibrosis completely when compared with normal control. CONCLUSION: GbE can partially protect rat liver from the fibrogenesis induced by CCl4. The mechanism may lie in its effect of inhibiting oxidative stress caused by liver injury and expressions of signal molecules such as TGF-beta1. GbE may thus be of potential help as a medicament or food additive for alleviation of liver fibrogenesis.

Alanine Transaminase↗
PubMed2005

Design considerations of volute geometry of a centrifugal blood pump.

This article compares two different design techniques that are conventionally used in the design of volutes for centrifugal pumps. The imbalanced forces due to the geometry of the volute need to be taken into consideration especially in centrifugal blood pumps with magnetically suspended impeller. A reduction of these forces can reduce the instability of the impeller motion as well as the power needed to counteract its influence. Volutes using the constant angular momentum (CAM) and the constant mean velocity (CMV) methods were developed and modeled numerically. The computational results on the effect of volute geometry on the performance of a centrifugal blood pump impeller for six different volutes are presented here. For volutes designed using the CAM method, model B (volute expansion angle of 3 degrees ) had the lowest radial force of 0.26 N while the pressure head generated was 12,900 Pa. For volutes designed using the CMV method, model F (1.6 m/s) had the lowest imbalanced force of 0.45 N. However, the pressure developed by this pump was also one of the lowest at 10,652 Pa. Furthermore, when the peak scalar stresses and the mean exposure time of particles for all designs were determined using Lagrangian particle tracking method, it was observed that in general, the peak scalar stresses in CAM designed volutes are lower than those designed using CMV method. The mean exposure time of particles in the pump ranged from 400 to 500 ms. The simulation results showed that the volute designed using CAM method was superior to that of a CMV volute in terms of the magnitude of the radial force and the peak scalar stresses for the same pressure head generated. Results show that the design of volutes for blood pumps should go beyond conventional empirical methods to obtain optimal results.

Centrifugation↗
PubMed2005

Identification of nuclear import and export signals within Fli-1: roles of the nuclear import signals in Fli-1-dependent activation of megakaryocyte-specific promoters.

The Ets factor Friend leukemia integration 1 (Fli-1) is an important regulator of megakaryocytic (Mk) differentiation. Here, we demonstrate two novel nuclear localization signals (NLSs) within Fli-1: one (NLS1) is located at the N terminus, and another (NLS2) is within the Ets domain. Nuclear accumulation of Fli-1 reflected the combined functional effects of the two discrete NLSs. Each NLS can independently direct nuclear transport of a carrier protein, with mutations within the NLSs affecting nuclear accumulation. NLS1 has a bipartite motif, whereas the NLS2 region contains a nonclassical NLS. Both NLSs bind importin alpha (IMPalpha) and IMPbeta, with NLS1 and NLS2 being predominantly recognized by IMPalpha and IMPbeta, respectively. Fli-1 also contains one nuclear export signal. Leptomycin B abolished its cytoplasmic accumulation, showing CRM1 dependency. We demonstrate that Ets domain binding to specific target DNA effectively blocks IMP binding, indicating that the targeted DNA binding plays a role in localizing Fli-1 to its destination and releasing IMPs for recycling back to the cytoplasm. Finally, by analyzing full-length Fli-1 carrying NLS1, NLS2, and combined NLS1-NLS2 mutations, we conclude that two functional NLSs exist in Fli-1 and that each NLS is sufficient to target Fli-1 to the nucleus for activation of Mk-specific genes.

Active Transport, Cell Nucleus↗