Biomedical subjects

Hua Wu

Publications and source records attributed to Hua Wu.

At least 19 recordsLinked to original sources

PubMed2007

Porous polylactide/chitosan scaffolds for tissue engineering.

Novel porous scaffolds were fabricated using biodegradable polylactide/chitosan blends. A combinational technique involving solvent-extracting, liquid-solid separation, and freeze-drying paths were employed. The processing parameters were optimized in order to produce desired porous scaffolds and thus obtained scaffolds showed well distributed and interconnected porous structures with controllable porosities varying from around 50-85% and regulative pore sizes being distributed within a region between 2 and 190 microm. These scaffolds exhibited remarkably improved hydrophilicity based on the measurements for their swelling index. The results obtained from in vitro incubation of scaffolds in phosphate buffered saline solutions at 37 degrees C during various periods up to 10 weeks indicated that chitosan component inside the scaffolds, on the one hand, effectively buffered the acidic degradation products of polylactide/chitosan scaffolds and on the other hand, the degradation of the scaffolds was also conspicuously delayed. These porous scaffolds maintained well-defined compressive mechanical properties and by well-blending polylactide with chitosan component, improved toughness on the resultant porous scaffolds was also observed.

Biocompatible Materials↗

PubMed2006

Production of cattle lacking prion protein.

Prion diseases are caused by propagation of misfolded forms of the normal cellular prion protein PrP(C), such as PrP(BSE) in bovine spongiform encephalopathy (BSE) in cattle and PrP(CJD) in Creutzfeldt-Jakob disease (CJD) in humans. Disruption of PrP(C) expression in mice, a species that does not naturally contract prion diseases, results in no apparent developmental abnormalities. However, the impact of ablating PrP(C) function in natural host species of prion diseases is unknown. Here we report the generation and characterization of PrP(C)-deficient cattle produced by a sequential gene-targeting system. At over 20 months of age, the cattle are clinically, physiologically, histopathologically, immunologically and reproductively normal. Brain tissue homogenates are resistant to prion propagation in vitro as assessed by protein misfolding cyclic amplification. PrP(C)-deficient cattle may be a useful model for prion research and could provide industrial bovine products free of prion proteins.

Animals↗

PubMed2006

A role for Alström syndrome protein, alms1, in kidney ciliogenesis and cellular quiescence.

Premature truncation alleles in the ALMS1 gene are a frequent cause of human Alström syndrome. Alström syndrome is a rare disorder characterized by early obesity and sensory impairment, symptoms shared with other genetic diseases affecting proteins of the primary cilium. ALMS1 localizes to centrosomes and ciliary basal bodies, but truncation mutations in Alms1/ALMS1 do not preclude formation of cilia. Here, we show that in vitro knockdown of Alms1 in mice causes stunted cilia on kidney epithelial cells and prevents these cells from increasing calcium influx in response to mechanical stimuli. The stunted-cilium phenotype can be rescued with a 5' fragment of the Alms1 cDNA, which resembles disease-associated alleles. In a mouse model of Alström syndrome, Alms1 protein can be stably expressed from the mutant allele and is required for cilia formation in primary cells. Aged mice developed specific loss of cilia from the kidney proximal tubules, which is associated with foci of apoptosis or proliferation. As renal failure is a common cause of mortality in Alström syndrome patients, we conclude that this disease should be considered as a further example of the class of renal ciliopathies: wild-type or mutant alleles of the Alström syndrome gene can support normal kidney ciliogenesis in vitro and in vivo, but mutant alleles are associated with age-dependent loss of kidney primary cilia.

Abnormalities, Multiple↗

PubMed2006

A generalized model for the stability of polymer colloids.

A generalized model has been proposed to describe the stability of polymer colloids stabilized with ionic surfactants by accounting simultaneously for the interactions among three important physicochemical processes: colloidal interactions, surfactant adsorption equilibrium, and association equilibria of surface charge groups with counterions at the particle-liquid interface. A few Fuchs stability ratio values, determined experimentally for various salt types and concentrations through measurements of the doublet formation kinetics, are used to estimate the model parameters, such as the surfactant adsorption and counterion association parameters. With the estimated model parameters, the generalized model allows one to monitor the dynamics of surfactant partitioning between the particle surface and the disperse medium, to analyze the variation of surface charge density and potential as a function of the electrolyte type and concentration, and to predict the critical coagulant concentration for fast coagulation. Three fluorinated polymer colloids, stabilized by perfluoropolyether-based carboxylate surfactant, have been used to demonstrate the feasibility of the proposed colloidal stability model.

Journal Article↗

PubMed2006

Orbitally driven spin-singlet dimerization in S=1 La4Ru2O10.

Using x-ray absorption spectroscopy at the Ru-L2,3 edge we reveal that the Ru4+ ions remain in the S=1 spin state across the rare 4d-orbital ordering transition and spin-gap formation. We find using local spin density approximation + Hubbard U band structure calculations that the crystal fields in the low-temperature phase are not strong enough to stabilize the S=0 state. Instead, we identify a distinct orbital ordering with a significant anisotropy of the antiferromagnetic exchange couplings. We conclude that La4Ru2O10 appears to be a novel material in which the orbital physics drives the formation of spin-singlet dimers in a quasi-two-dimensional S=1 system.

Journal Article↗

PubMed2006

Post-traumatic hepatic artery pseudo-aneurysm combined with subphrenic liver abscess treated with embolization.

A 23-year-old man with post-traumatic hepatic artery pseudo-aneurysm and subphrenic liver abscess was admitted. He underwent coil embolization of hepatic artery pseudo-aneurysm. The pseudo-aneurysm was successfully obstructed and subphrenic liver abscess was controlled. Super-selective trans-catheter coil embolization may represent an effective treatment for hepatic artery pseudo-aneurysm combined with subphrenic liver abscess in the absence of other therapeutic alternatives.

Adult↗

PubMed2006

Detailed model of the aggregation event between two fractal clusters.

A model has been developed for describing the aggregation process of two fractal clusters under quiescent conditions. The model uses the approach originally proposed by Smoluchowski for the diffusion-limited aggregation of two spherical particles but accounts for the possibility of interpenetration between the fractal clusters. It is assumed that when a cluster diffuses toward a reference cluster their center-to-center distance can be smaller than the sum of their radii, and their aggregation process is modeled using a diffusion-reaction equation. The reactivity of the clusters is assumed to depend on the reactivity and number of their particles involved in the aggregation event. The model can be applied to evaluate the aggregation rate constant as a function of the prevailing operating conditions by simply changing the value of the particle stability ratio, without any a priori specification of a diffusion-limited cluster aggregation, reaction-limited cluster aggregation, or transition regime. Furthermore, the model allows one to estimate the structure properties of the formed cluster after the aggregation, based on the computed distance between the aggregating clusters in the final cluster.

Journal Article↗

PubMed2006

Using anti-VEGF McAb and magnetic nanoparticles as double-targeting vector for the radioimmunotherapy of liver cancer.

To study the biodistribution of a new radioimmunoconjugate-131I-anti-VEGF monoclonal antibody (Sc-7269)-Dextran Magnetic Nanoparticles (DMN) in nude mice bearing human liver cancer where an external magnetic field was focused on, and to evaluate its therapeutic effects and safety. Tumor Growth Delay (TGD) and tumor inhibition rate were observed as antitumor effect. Peripheral white blood cells counts and the loss of body weight were tested as an indicator of systemic toxicity. The results suggests that the radioimmunotherapy of intratumoral injection of 131I-Sc-7269-DMN may be safe and efficient for the treatment of liver cancer. Furthermore, the radioimmunotherapy using DMN as a 'carrier system' may be a highly potential approach in the treatment of other kind of tumors.

Animals↗

PubMed2006

Detection of ischemic myocardium with a new hypoxic tissue targeting tracer 99Tc(m)-HL91.

The imaging appearances of 99Tc(m)-HL91, a new hypoxic imaging agent, in ischemic myocardium were studied and the value of 99Tc(m)-HL91 in the evaluation of regional ischemic viable myocardium was explored. Acute myocardial ischemia models were made by coronary artery legations in 18 rats and randomly divided into 2 groups: 99Tc(m)-HL91 group and 99Tc(m)-MIBI group. Evan blue infusion during ischemia and TTC staining after operation were used to delineate the area of ischemic and viable myocardium. The isolated heart was sliced in the short axis and then autoradiography was performed. The electron microscopic examination was also done for the myocardial samples. 99Tc(m)-HL91 and 99Tc(m)-MIBI uptake activities (counts/g) were measured in the area of ischemic myocardium (T) and normal myocardium (NT) separately. The uptake ratios of 99Tc(m)-HL91 and that of 99Tc(m)-MIBI in ischemic myocardium were calculated as T/NT. It was found that the normal myocardium was blue and ischemic or infarct myocardium was negative with Evans blue in all experiment rats. Both the normal and ischemic myocardium was in red color with TTC staining. In the 99Tc(m)-HL91 group the ischemic myocardium showed much higher uptake over normal myocardium, that was demonstrated both in the autoradiography and quantitative analysis. The ischemic/normal activity ratios were 1.634 +/- 0.354. It was suggested that 99Tc(m)-HL91 might accumulate in ischemic and viable myocardium, which is helpful in the evaluation of hypoxic but viable myocardium and potentially used as a imaging agent to assess myocardial viability.

Animals↗

PubMed2006

Biodegradable polylactide/chitosan blend membranes.

Biodegradable blend membranes based on polylactide and chitosan with various compositions were prepared via a two-step processing pathway. In the first step, solutions of each component were properly mixed and cast into a gelatinous membrane, and in the second step, the obtained membrane was immersed into a mixed solution for the solvent extraction followed by a drying procedure to finally generate a well-blended membrane. An acetic acid-acetone solvent system was selected for poly(DL-lactide)/chitosan membranes, and another solvent system for poly(L-lactide)/chitosan membranes consisted of acetic acid and dimethyl sulfoxide. Some processing parameters, such as the concentration of component solutions and the composition ratio of mixed solvents and extraction solvents, were optimized by primarily considering whether the directly visible phase separation occurred during the processing procedures. Morphologies of these blend membranes were viewed using SEM. It was found that the processing parameters exerted quite notable impacts on the morphology of the membranes. The hydrophilicity of membranes was examined by measuring their water contact angle and swelling index. These blend membranes were also investigated for their miscibility using IR spectra, X-ray diffractograms, TG, DSC, and dynamic mechanical analysis methods. Although the presence of phase separation at a microscopic level was detected for these membranes, pronounced interactions between components were confirmed. The obtained results shown that some membranes prepared under optimized processing conditions had a partially miscible structure.

Acetic Acid↗

PubMed2006

Major histocompatibility complex class II variation in the giant panda (Ailuropoda melanoleuca).

Habitat destruction and human activity have greatly impacted the natural history of the giant panda (Ailuropoda melanoleuca). Although the genetic diversity of neutral markers has been examined in this endangered species, no previous work has examined adaptive molecular polymorphisms in the giant panda. Here, the major histocompatibility complex (MHC) class II DRB locus was investigated in the giant panda, using single-strand conformation polymorphism (SSCP) and sequence analysis. Comparisons of DNA samples extracted from faecal and blood samples from the same individual revealed that the two materials yielded similar quantities and qualities of DNA, as well as identical SSCP patterns and allelic sequences, demonstrating the reliability of DNA isolation from panda faeces. Analysis of faecal samples from 60 giant pandas revealed relatively low number of alleles: seven alleles. However, the alleles were quite divergent, varying from each other by a range of 7-47 nucleotide substitutions (4-25 amino acid substitutions). Construction of a neighbour-joining tree and comparisons among DRB alleles from other species revealed that both similar and highly divergent alleles survived in the bottlenecked panda populations. Despite species-specific primers used and excellent faecal DNA isolated, a lower level of heterozygosity than expected was still observed due to inbreeding. There were three types of evidence supporting the presence of balancing selection in the giant panda: (i) an obvious excess of nonsynonymous substitutions over synonymous at the antigen-binding positions; (ii) trans-species evolution of two alleles between the giant panda and other felids; and (iii) a more even distribution of alleles than expected from neutrality.

Alleles↗

PubMed2005

Ginsenoside extraction from Panax quinquefolium L. (American ginseng) root by using ultrahigh pressure.

A new method of ultrahigh pressure extraction (UPE) was used to extract the ginsenosides from Panax quinquefolium L. (American ginseng) root at room temperature. Several solvents, including water, ethanol, methanol, and n-butanol were used in the UPE. The ginsenosides were quantified by a HPLC equipped with UV-vis detector. The results showed that ethanol is the most efficient solvent among the used ones. Compared with other methods, i.e., Soxhlet extraction, heat reflux extraction, ultrasound-assisted extraction, microwave-assisted extraction, and supercritical CO2 extraction, the UPE has the highest extraction yield in the shortest time. The extraction yield of 0.861% ginsenoside-Rc in 2 min was achieved by the UPE, while the yields of 0.284% and 0.661% were obtained in several hours by supercritical CO2 extraction and the heat reflux extraction, respectively.

Carbon Dioxide↗

PubMed2005

[The protective effects to the function of kidney and long by clearing of cytokines in patients with open-heart surgery].

OBJECTIVE: To observe the effect of cytokines absorption on renal and respiratory function in patients with open-heart surgery. METHODS: 30 patients undergoing valve replacement with cardiopulmonary bypass (CPB) were randomly divided into two groups. A sulfonated polyacrylonitrile hemofilter (AN69) that has been used to absorb cytokines was connected into the efferent limb of CPB in Group A (n = 15), and a cellulose triacetate hemofilter (CT 190G) instead of AN69 was used as controls (Group B, n = 15). The levels of plasma pro-inflammatory (TNF-alpha, IL-6, IL-8) anti-inflammatory cytokines (IL-10, IL-1ra), C-reactive protein (CRP) levels, and post-operation renal and respiratory function were compared between the two groups. Blood samples were analysed for TNF-alpha and IL-6 and IL-8 and C-reactive protein (CRP). The changes in renal, respiratory function were also observed. RESULTS: (1) At the end of CPB, TNF-alpha 10 ng/L +/- 3 ng/L and IL-6 115 ng/L +/- 22 ng/L levels in Group A were significantly lower than that in Group B 13 ng/L +/- 3 ng/L, 134 ng/L +/- 29 ng/L) respectively (P < 0.05 in all). There is no statistical differences in plasma IL-10 and IL-1ra levels between the two groups. (2) After 24 hours of CPB, the magnitude of increased body temperature, heart rate, white blood cell and plasma CRP in Group A [1.6 degrees C +/- 0.2 degrees C, 15/min +/- 4/min, (17 +/- 3) x 10(9)/L, 56 mg/L +/- 13 mg/L], were significantly lower than that in Group B [2.1 degrees C +/- 0.2 degrees C, 23/min +/- 6/min, (22 +/- 3) x 10(9)/L, 69 mg/L +/- 15 mg/L] respectively (P < 0.05 in all). (3) After 24 hours of CPB, the levels of 24h urinary protein excretion and urinary N-acetyl-beta-D-glucosaminidase (NAG) were significantly lower in Group A when compared to that in Controls (0.20 g/d +/- 0.08 g/d vs 0.30 g/d +/- 0.14 g/d, 28 U/L +/- 11 U/L vs 38 U/L +/- 13 U/L respectively), P < 0.05 in all. The level of creatinine clearance (Ccr) in Group A (68 +/- 7) ml.min(-1).1.73 m(-2) was significantly elevated than that in Group B (57 +/- 11) ml.min(-1).1.73 m(-2) (P < 0.05). (4) One hour after the end of CPB, the magnitude of increased plateau airway pressure (P(Plateau)) and peak airway pressure (P(Peak)) in Group A were significantly lower than that in Controls (P < 0.01 in all). The duration that need mechanical ventilation after operation in Group A (4.9 h +/- 0.6 h) was much shorter than that in Group B (5.8 h +/- 0.8 h, P < 0.05). CONCLUSIONS: Lowering the plasma levels of cytokines by extracorporeal absorption may attenuate systemic inflammatory response and protect lung and kidney function in patients with open-heart surgery.

Adsorption↗

PubMed2005

Nature of magnetism in Ca3Co2O6.

We find using local spin density approximation + Hubbard U band structure calculations that the novel one-dimensional cobaltate Ca3Co2O6 is not a ferromagnetic half-metal but a Mott insulator. Both the octahedral and the trigonal Co ions are formally trivalent, with the octahedral being in the low-spin and the trigonal in the high-spin state. The inclusion of the spin-orbit coupling leads to the occupation of the minority-spin d2 orbital for the unusually coordinated trigonal Co, producing a giant orbital moment (1.57 microB). It also results in an anomalously large magnetocrystalline anisotropy (of order 70 meV), elucidating why the magnetism is highly Ising-like. The role of the oxygen holes, carrying an induced magnetic moment of 0.13 microB per oxygen, for the exchange interactions is discussed.

Journal Article↗

PubMed2005

Functional, biochemical, and chromatographic characterization of the complete [Ca2+]i oscillation-inducing activity of porcine sperm.

A cytosolic sperm protein(s), referred to as sperm factor (SF), is delivered into eggs by the sperm during mammalian fertilization to induce repetitive increases in the intracellular concentration of free Ca2+ ([Ca2+]i) that are referred to as [Ca2+]i oscillations. [Ca2+]i oscillations are essential for egg activation and early embryonic development. Recent evidence shows that the novel sperm-specific phospholipase C (PLC), PLCzeta, may be the long sought after [Ca2+]i oscillation-inducing SF. Here, we demonstrate the complete extraction of SF from porcine sperm and show that regardless of the method of extraction a single molecule/complex appears to be responsible for the [Ca2+]i oscillation-inducing activity of these extracts. Consistent with this notion, all sperm fractions that induced [Ca2+]i oscillations, including FPLC-purified fractions, exhibited high in vitro PLC activity at basal Ca2+ levels (0.1-5 microM), a hallmark of PLCzeta. Notably, we detected immunoreactive 72-kDa PLCzeta in an inactive fraction, and several fractions capable of inducing oscillations were devoid of 72-kDa PLCzeta. Nonetheless, in the latter fractions, proteolytic fragments, presumably corresponding to cleaved forms of PLCzeta, were detected by immunoblotting. Therefore, our findings corroborate the hypothesis that a sperm-specific PLC is the main component of the [Ca2+]i oscillation-inducing activity of sperm but provide evidence that the presence of 72-kDa PLCzeta does not precisely correspond with the Ca2+ releasing activity of porcine sperm fractions.

Animals↗

PubMed2005

[Late course conformal radiotherapy combined with chemotherapy for stage III and IV a nasopharyngeal carcinoma].

OBJECTIVE: To evaluate the effect and acute toxicity of late course conformal radiotherapy combined with chemotherapy for stage III and IV a nasopharyngeal carcinoma (NPC). METHODS: Ninety-six patients with stage III and IV a NPC were randomly divided into 2 groups: test group (n = 46, undergoing late course conformal radiotherapy combined with chemotherapy) and control group (n = 50, undergoing conventional radiotherapy). Both groups were treated with one-period chemotherapy, including cisplantin, 5-fluouracil, and calcium folinate, before and after the radiotherapy. The radiotherapy of the test group consisted of 2 phases: 36.0 approximately 40.0 Gy in 18 approximately 20 fractions over 3.5-4 weeks as the first phase using conventional technique was delivered with 2 lateral opposing faciocervical fields, and then 30.0-46.0 Gy in 15-23 fractions over 3-4.5 weeks as the second phase using three-dimensional conformal radiotherapy (3D-CRT). RESULTS: The rates of complete remission (CR), partial remission (PR), and no change (NC) of the test group were 95.65%, 4.35%, and 0, not significantly different from those in the control group (90.00%, 10.00%, and 0, P = 0.287). The 1-year survival rate of the test group was 100%, not significantly different from that of the control group (96.00%, P = 0.170). The nasopharyngeal 1 year control rate of the test group was 97.83%, significantly higher than that of the control group (78.00%, P = 0.03). The distant metastasis rate of the test group was 8.70%, not significantly different from that of the control group (12.00%, P = 0.596). The incidence rates of radiological caries and irradiation-induced otitis media in the test group was 4.25% and 17.39% respectively, both significantly lower than those in the control group (26.00% and 42.00% respectively, P = 0.004 and P = 0.000). There was no significant difference in the incidence of nausea, vomiting, leukopenia, and severity of acute mucositis between these 2 groups. CONCLUSION: Late course conformal radiotherapy combined with chemotherapy effectively improves the disease control, delays the distant metastasis, and alleviates radioactivity damnification.

Adolescent↗

PubMed2005

Scattering structure factor of colloidal gels characterized by static light scattering, small-angle light scattering, and small-angle neutron scattering measurements.

The scattering structure factor of a colloidal gel in a q range of 5 orders of magnitude has been determined by combining static light scattering, small-angle light scattering, and neutron scattering measurements. It exhibits simultaneously two types of structure information: a mass fractal scaling within the clusters that constitute the gel and a surface fractal scaling for length scales larger than that of the clusters. Such scattering behavior can be well interpreted by the pair-correlation function proposed in the literature to model an ideal structure constituted of mass fractal objects inside surface fractal objects.

Journal Article↗

PubMed2005

Application of mitochondrial DNA sequence analysis in the forensic identification of Chinese sika deer subspecies.

As a direct and indirect consequence of human activities, only two subspecies, Cervus nippon sinchuanicus and Cervus nippon kopschi, currently subsist in the wild of China. However, a large population of Cervus nippon hortulorum and Cervus nippon nippon is raised in order to gain deer parts for Chinese traditional medicine. According to Chinese Wild Animal Conservation Law, hunting, capturing and trading of the wild sika deer are strictly banned, however, raising and trading of the domestic individual are permitted. Thus, it is very necessary to identify the subspecies of sika deer in China in forensic tests. In our study, we used mitochondrial DNA control region sequence analysis and phylogenetic analysis to identify the subspecies of sika deer. Mitochondrial DNA control region sequences analysis revealed that two haplotypes came from the unknown samples. One is the same as the haplotype that came from the samples of wild population of C. n. kopschi. Phylogenetic analysis indicated that the two haplotypes of unknown samples clustered with the haplotypes of C. n. kopschi, and had significant difference from the haplotypes of the other subspecies. These results together revealed that the unknown samples came from two individuals that belong to the wild population of C. n. kopschi living in the Qinglingfeng State Natural Reserve of Zhejiang province. Therefore, the results provide forensic evidence of illegal wild animal hunting.

Animals↗