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Biomedical subjects

Hui Zhang

Publications and source records attributed to Hui Zhang.

At least 109 records · Page 6Linked to original sources
PubMed2006

Enhanced immunogenicity of the modified GP5 of porcine reproductive and respiratory syndrome virus.

The ORF5-encoded major envelope glycoprotein (GP5) is one of the key immunogenic proteins of the porcine reproductive and respiratory syndrome virus (PRRSV) and is the leading target for the development of the new generation of vaccines against PRRS. However, weak and tardy neutralizing antibodies have been elicited in several developed experimental vaccines expressing PRRSV GP5. More recent evidence has demonstrated a non-neutralizing decoy epitope upstream of the neutralizing epitope of GP5, which might prevent the development of a strong neutralizing antibody response against PRRSV. In the present study, we modified the ORF5 gene by inserting a Pan DR T-helper cell epitope (PADRE) between the neutralizing epitope and the decoy epitope to minimize or eliminate the decoy effect of the non-neutralizing epitope. The immunogenicity of the modified GP5 was further evaluated using DNA vaccination. The results showed that significantly enhanced neutralizing antibodies were elicited in mice immunized with the DNA construct expressing the modified GP5 compared with the native GP5. Slightly increased levels of GP5-specific ELISA antibodies and T-cell proliferative activities were also observed. These results indicate that the high immunogenicity of the modified GP5 might facilitate the development of improved PRRS vaccines in the future.

Amino Acid Sequence↗
PubMed2006

Selective killing of oncogenically transformed cells through a ROS-mediated mechanism by beta-phenylethyl isothiocyanate.

Reactive oxygen species (ROS) stimulate cell proliferation and induce genetic instability, and their increase in cancer cells is often viewed as an adverse event. Here, we show that such abnormal increases in ROS can be exploited to selectively kill cancer cells using beta-phenylethyl isothiocyanate (PEITC). Oncogenic transformation of ovarian epithelial cells with H-Ras(V12) or expression of Bcr-Abl in hematopoietic cells causes elevated ROS generation and renders the malignant cells highly sensitive to PEITC, which effectively disables the glutathione antioxidant system and causes severe ROS accumulation preferentially in the transformed cells due to their active ROS output. Excessive ROS causes oxidative mitochondrial damage, inactivation of redox-sensitive molecules, and massive cell death. In vivo, PEITC exhibits therapeutic activity and prolongs animal survival.

Animals↗
PubMed2006

Analyses of RAS regulation of eye development in Drosophila melanogaster.

Many aspects of Drosophila eye development depend on receptor tyrosine kinases that signal through Ras. Genetic studies and genetic screens using eye morphology and development as assays have identified major components of receptor tyrosine kinase and Ras signaling and outlined specific contributions of these components to cell fate specification and differentiation, cell survival, cell cycle progression and arrest, and cellular movements and morphology. This chapter presents a brief compendium of methods and strains that may be used to obtain overexpression or loss of function for Ras pathway genes in the eye and methods and reagents permitting initial characterization of retinal cell differentiation, death, and cell cycle behavior.

Animals↗
PubMed2006

Treatment strategy to optimize radiofrequency ablation for liver malignancies.

PURPOSE: The purposes of this study were to investigate a treatment strategy to increase liver tumor necrosis and minimize complications with ultrasound-guided percutaneous radiofrequency (RF) ablation and to evaluate its therapeutic efficacy. MATERIALS AND METHODS: A total of 332 patients with 503 liver malignancies underwent RF ablation according to a mathematical protocol with adjunctive measures. In the 332 patients, 205 had 308 hepatocellular carcinomas (HCCs) with a mean largest diameter of 4.1 cm and 127 had 195 metastatic liver carcinomas (MLCs) with a mean largest diameter of 3.9 cm. In patients with HCC, 60 (29.3%) had stage I/II disease and 145 (70.7%) had stage III/IV disease. Depending on tumor size, shape, and location, a defined treatment strategy was adopted that consisted of a mathematical protocol, an individualized protocol, and adjunctive measures. The mathematical protocol was followed for tumors larger than 3.5 cm. The individualized protocol was used for tumors located adjacent to the diaphragm, gastrointestinal tract, or gallbladder. Some adjunctive measures such as supplementary fine needle localization, local saline solution injection, and feeding vessel ablation were used to deal with different features of these liver tumors. Patients were followed regularly to assess treatment efficiency, and the tumor was considered to have early complete necrosis if no viability was found on enhanced computed tomography 1 month after RF ablation. RESULTS: In this series, the early necrosis rates were 95.8% for HCC (295 of 308 tumors), 94.9% for MLC (185 of 195 tumors), 91.3% for tumors larger than 3.5 cm (189 of 207 tumors), 90.7% for tumors near the gastrointestinal tract (49 of 54 tumors), 91.5% for tumors near the diaphragm (86 of 94 tumors), and 90.6% for tumors near the gallbladder (48 of 53 tumors). The local recurrence rates were 10.7% for HCC (33 of 308 tumors) and 14.9% for MLC (29 of 195 tumors). The 1-, 2-, and 3-year overall survival rates were 89.6%, 69.4%, and 59.6%, respectively, for HCC and 80.3%, 52.8%, and 30.9%, respectively, for MLC. The 1-, 2-, and 3-year survival rates in 60 patients with stage I/II HCC were 93.7%, 87.1%, and 76.2%, respectively. The incidence of major complications was 1.4% (eight of 574 sessions), which included of three hemorrhages, four injuries to adjacent structures, and one case of needle tract seeding. CONCLUSION: In RF ablation of hepatic tumors, application of a proper protocol and adjunctive measures play important roles in improving tumor necrosis rate and minimizing potential complications.

Adult↗
PubMed2006

Needle biopsy of anatomically unfavorable liver lesions with an electromagnetic navigation assist device in a computed tomography environment.

PURPOSE: Emerging interventional radiology assistance systems that incorporate electromagnetic navigation (EMN) can help the operator guide a needle or other instrument toward a target along preplanned oblique trajectories while avoiding critical structures. A proof-of-concept study was conducted to assess the use of EMN, and EMN was compared with the standard computed tomographic (CT) fluoroscopy guidance technique. MATERIALS AND METHODS: A total of 14 needle passes, seven each with EMN and CT fluoroscopy guidance, were performed into an artificially created liver lesion of a single swine. The accuracy of needle placement for each pass was verified with a confirmatory CT scan. The total radiation dose and time of procedure was compared between the EMN and conventional CT fluoroscopy methods. RESULTS: All needle passes were successful, and all passes conducted with EMN were completed with a single insertion, whereas multiple passes (mean, 2.9) with needle repositioning were required with CT fluoroscopic guidance. Statistically significant reduction in procedure time and overall radiation dose for EMN punctures was shown. Accuracy of needle placement was statistically equivalent for the two methods. CONCLUSIONS: This proof-of-concept study shows that EMN guidance has equivalent accuracy of needle placement to conventional CT fluoroscopy-guided methods in swine. EMN is also associated with favorable radiation-dose and time-of-procedure profiles for biopsy of liver lesions. Clinical studies are needed to evaluate the safety and efficacy of this technology in the biopsy of lesions in anatomically challenging locations that require steep angles of needle insertion.

Animals↗
PubMed2006

Continuous medial representation for anatomical structures.

The m-rep approach pioneered by Pizer et al. (2003) is a powerful morphological tool that makes it possible to employ features derived from medial loci (skeletons) in shape analysis. This paper extends the medial representation paradigm into the continuous realm, modeling skeletons and boundaries of three-dimensional objects as continuous parametric manifolds, while also maintaining the proper geometric relationship between these manifolds. The parametric representation of the boundary-medial relationship makes it possible to fit shape-based coordinate systems to the interiors of objects, providing a framework for combined statistical analysis of shape and appearance. Our approach leverages the idea of inverse skeletonization, where the skeleton of an object is defined first and the object's boundary is derived analytically from the skeleton. This paper derives a set of sufficient conditions ensuring that inverse skeletonization is well-posed for single-manifold skeletons and formulates a partial differential equation whose solutions satisfy the sufficient conditions. An efficient variational algorithm for deformable template modeling using the continuous medial representation is described and used to fit a template to the hippocampus in 87 subjects from a schizophrenia study with sub-voxel accuracy and 95% mean overlap.

Algorithms↗
PubMed2006

Dynamics of CD4+CD25+ T cells in spleens and mesenteric lymph nodes of mice infected with Schistosoma japonicum.

CD4+CD25+ T cells play a major role in modulating immune response, but few reports have been published about schistosomiasis. Here, we investigated the changes in CD4+CD25+ T cell populations in spleens and mesenteric lymph nodes of mice infected with Schistosoma japonicum. The proportions of CD4+CD25+ T cells in total CD4+ T cells were analyzed by flow cytometry. CD25 and Foxp3 expression was measured by real-time quantitative polymerase chain reaction. The suppressive activities of CD4+CD25+ T cells were detected by in vitro proliferation of splenocytes. Evidence showed that the percentage of CD4+CD25+ T cells was the same as controls 3 weeks post-infection. At the acute stage of infection, the percentage decreased significantly. However, at the chronic stage of infection, it rebounded to normal levels or even higher. The expression of the CD25 and Foxp3 showed gradual increase along with the infection progress. In vitro experiment also showed the strong suppressive effect of CD4+CD25+ T cells, isolated during the chronic stage, on proliferation of the CD25- splenocytes. This is the first time that the dynamics of CD4+CD25+ T cell populations was demonstrated in mice infected with schistosomiasis. In conclusion, our data indicated that CD4+CD25+ cells might be involved in the immune modulation during S. japonicum infection, which enhances current knowledge of the mechanisms of the immuno-downregulation and re-infection in schistosomiasis.

Animals↗
PubMed2006

Alpha interferon potently enhances the anti-human immunodeficiency virus type 1 activity of APOBEC3G in resting primary CD4 T cells.

The interferon (IFN) system, including various IFNs and IFN-inducible gene products, is well known for its potent innate immunity against wide-range viruses. Recently, a family of cytidine deaminases, functioning as another innate immunity against retroviral infection, has been identified. However, its regulation remains largely unknown. In this report, we demonstrate that through a regular IFN-alpha/beta signal transduction pathway, IFN-alpha can significantly enhance the expression of apolipoprotein B mRNA-editing enzyme-catalytic polypeptide-like 3G (APOBEC3G) in human primary resting but not activated CD4 T cells and the amounts of APOBEC3G associated with a low molecular mass. Interestingly, short-time treatments of newly infected resting CD4 T cells with IFN-alpha will significantly inactivate human immunodeficiency virus type 1 (HIV-1) at its early stage. This inhibition can be counteracted by APOBEC3G-specific short interfering RNA, indicating that IFN-alpha-induced APOBEC3G plays a key role in mediating this anti-HIV-1 process. Our data suggest that APOBEC3G is also a member of the IFN system, at least in resting CD4 T cells. Given that the IFN-alpha/APOBEC3G pathway has potent anti-HIV-1 capability in resting CD4 T cells, augmentation of this innate immunity barrier could prevent residual HIV-1 replication in its native reservoir in the post-highly active antiretroviral therapy era.

3T3 Cells↗
PubMed2006

Serum level of homocysteine is correlated to carotid artery atherosclerosis in Chinese with ischemic stroke.

OBJECTIVES: To investigate the relationship between serum level of homocysteine (Hcy) and carotid artery atheroscleosis (CAA). METHODS: Both sides of the common carotid artery and internal carotid artery in 126 Chinese patients with ischemic stroke were measured by B-mode ultrasound. The patients were divided into groups: normal, A, B, C and D according to the severity of CAAs. With fasting serum, Hcy as well as folate, vitamin B(12) and lipids were detected. The mean +/- SD age was 64 +/- 13 years (range 39-87 years). RESULTS: In a logistic regression model, the Hcy concentrations were associated with an elevated risk of CAAs independent of all traditional risk factors, and when CAAs became severer, the serum Hcy was higher. The levels of the normal group and A, B, C, D groups were 13.22 +/- 6.15 micromol/L, 16.29 +/- 9.81 micromol/l, 19.49 +/- 11.16 micromol/l, 27.21 +/- 17.47 micromol/l, and 24.14 +/- 8.64 micromol/l, respectively. Rank test showed a significant difference between normal and other groups (p<0.05). The levels of folate and vitamin B(12) were negatively correlated with the Hcy concentrations. Spearman correlation coefficient were -0.23 and -0.42 (p<0.05). CONCLUSIONS: Hyperhomocysteinaemia is an independent risk factor of CAAs and the degree of CAAs is highly correlated with the level of Hcy in serum. The causes of hyperhomocysteinemia may be the result from the decrease in folate and vitamin B(12). Clinical trials are now required to evaluate the effect of treatment with these vitamins on the primary and secondary prevention of cerebral vascular diseases.

Adult↗
PubMed2006

Accumulation of gamma-aminobutyric acid in rice germ using protease.

The accumulation of gamma-aminobutyric acid (GABA) in the rice germ by using protease was investigated. After the proteolytic hydrolysis of germ protein by trypsin, the amount of GABA reached about 2.26 g per 100 g of germ. This demonstrates that the GABA yield could be significantly increased by protease. Our method is efficient and safe for manufacturing health food enriched with GABA.

Food Handling↗
PubMed2006

Isolation of glycoproteins and identification of their N-linked glycosylation sites.

Protein glycosylation has long been recognized as a very common posttranslational modification. Protein glycosylation is prevalent in proteins destined for extracellular environments. These include proteins localized on the extracellular surface and those secreted to body fluids. In search of a method that has the potential to identify and quantify most proteins found in body fluids or the cell surface, we have recently developed a novel method for solid-phase extraction of formerly N-linked glycosylated peptides from glycoproteins. It has been shown that proteins secreted to body fluids or localized on the cell surface can be specifically enriched by this method. The technique is based on the conjugation of glycoproteins to a solid support using hydrazide chemistry, removal of nonglycosylated peptides by trypsin digestion, stable isotope labeling of glycopeptides, and the specific release of formerly N-linked glycosylated peptides via peptide-N-glycosidase. The recovered formerly N-linked glycopeptides are then identified and quantified by tandem mass spectrometry.

Animals↗
PubMed2006

Optimization analysis of decentralised sanitation and re-use system.

With the application of system dynamics, a dynamic nonlinear model reflecting the relationship between decentralised water use and reclaimed water supply and demand has been established. Through a system analysis, the model has been applied to a small residential district to predict and analyse the situation of future use of fresh water, demand and supply of re-used water, and treatment scale of reclaimed water. It is illustrated in this paper that wastewater decentralised treatment and re-use can decrease the consumption of fresh water without lowering the standard of living water for the district residents. On this basis, a rational scale and construction time of the decentralised sanitation and re-use system have been determined. Also, the paper predicts the influencing factors of the increasing water cost and changes in consumers' acceptability to re-use water in the decentralised sanitation and re-use system.

China↗
PubMed2006

Electromagnetic tracking for abdominal interventions in computer aided surgery.

Electromagnetic tracking has great potential for assisting physicians in precision placement of instruments during minimally invasive interventions in the abdomen, since electromagnetic tracking is not limited by the line-of-sight restrictions of optical tracking. A new generation of electromagnetic tracking has recently become available, with sensors small enough to be included in the tips of instruments. To fully exploit the potential of this technology, our research group has been developing a computer aided, image-guided system that uses electromagnetic tracking for visualization of the internal anatomy during abdominal interventions. As registration is a critical component in developing an accurate image-guided system, we present three registration techniques: 1) enhanced paired-point registration (time-stamp match registration and dynamic registration); 2) orientation-based registration; and 3) needle shape-based registration. Respiration compensation is another important issue, particularly in the abdomen, where respiratory motion can make precise targeting difficult. To address this problem, we propose reference tracking and affine transformation methods. Finally, we present our prototype navigation system, which integrates the registration, segmentation, path-planning and navigation functions to provide real-time image guidance in the clinical environment. The methods presented here have been tested with a respiratory phantom specially designed by our group and in swine animal studies under approved protocols. Based on these tests, we conclude that our system can provide quick and accurate localization of tracked instruments in abdominal interventions, and that it offers a user-friendly display for the physician.

Abdomen↗
PubMed2006

Glucose metabolism in patients with schizophrenia treated with olanzapine or quetiapine: a frequently sampled intravenous glucose tolerance test and minimal model analysis.

OBJECTIVE: Clozapine and olanzapine treatment has been associated with insulin resistance in non-obese schizophrenia patients. Much less is known regarding other agents such as quetiapine. The objective of this study was to compare matched olanzapine- and quetiapine-treated schizophrenia patients and normal controls on measures of glucose metabolism. METHOD: A cross-sectional comparison of quetiapine-treated and olanzapine-treated non-obese (body mass index < 30.0 kg/m2) schizophrenia subjects (DSM-IV) with matched normal controls using a frequently sampled intravenous glucose tolerance test and nutritional assessment was conducted from April 2002 to October 2004. Data from 24 subjects were included in the analysis (7 quetiapine, 8 olanzapine, 9 normal controls). RESULTS: There was a significant difference among groups for fasting baseline plasma glucose concentrations (p = .02), with olanzapine greater than normal controls (p = .01). The insulin sensitivity index (SI) differed significantly among groups (p = .039); olanzapine subjects exhibited significant insulin resistance compared to normal controls (p = .01), but there was no significant difference for quetiapine versus olanzapine (p = .1) or quetiapine versus normal controls (p = .40). SI inversely correlated with quetiapine dose (p = .0001) and waist circumference (p = .03) in quetiapine-treated subjects. Insulin resistance calculated by the homeostasis model assessment of insulin resistance (HOMA-IR) also differed significantly among groups (p = .03). The olanzapine group had a higher HOMA-IR level than normal controls (p = .01). There was a significant difference in glucose effectiveness (SG) among the groups (p = .049). SG was lower in the olanzapine group than in the quetiapine group (p = .03) and in the olanzapine group compared to normal controls (p = .049). CONCLUSIONS: Our findings are consistent with our previous report that nonobese olanzapine-treated subjects showed insulin resistance, measured by both HOMA-IR and SI, and reduction in SG. Studies that include larger samples, unmedicated patients, and varying durations of antipsychotic exposure are necessary to confirm these results.

Adult↗
PubMed2006

[Cr-Ti-Al-N complex coating on titanium to strengthen Ti/porcelain bonding].

OBJECTIVE: To study the feasibility of magnetron sputtering Cr-Ti-Al-N complex coating as an interlayer on titanium to enhance the titanium-ceramic binding strength. METHODS: With a three-point bending test according to ISO 9693, the binding strength of Duceratin (Degussa) to titanium substrate prepared with 4 different surface treatments (polishing, polishing and megnetron sputtering Cr, Ti, Al, and N complex coating, sandblasting, sandblasting and coating) was evaluated. Ti/porcelain interface and fractured Ti surface were examined using scanning electron microscopy with energy-dispersive spectrometry (EDS). RESULTS: The binding strength of polished and coated titanium/Duceratin was significantly higher than polished titanium group (P<0.05). The binding strength of sandblasted and coated titanium/Duceratin did not differ significantly from that of sandblasted titanium group (P>0.05), and the strength in the two sandblasted titanium groups was significantly higher than that in polished and coated titanium group (P<0.05). CONCLUSION: Megnetron sputtering Cr-Ti-Al-N complex on polished titanium can increase the titanium/porcelain binding strength. Megnetron sputtering coating is a promising Ti/porcelain interlayer.

Aluminum↗
PubMed2006

[Cellular immune responses specific for CD8+ T cell epitopes delivered by attenuated Salmonella typhimurium].

AIM: To investigate cellular immune responses against CD8(+) T cell epitopes delivered by attenuated Salmonella. METHODS: Prokaryotic expression plasmid ptG2F, carrying the oligonucleotide fragment encoding CD8(+) T cell epitope of OVA 257-264aa and LCMV NP 118-132aa fused with GFP gene was constructed and electro-transformed into the attenuated strain SL7207 of Salmonella typhimurium. The recombinant bacteria, named as SL7207(ptG2F), were screened out. C57BL/6 and BALB/c mice were immunized intravenously with SL7207(ptG2F) at two weeks intervals. Murine IFN-gamma and IL-4 secreting cells were detected in murine splenocytes after second and third immunization by Enzyme-linked immunospot assay (ELISPOT). RESULTS: The recombinant bacteria SL7207(ptG2F) induced cellular immune responses. When OVA CD8(+) T cell epitope was presented by the recombinant bacteria, the immune responses were biased toward Th1 response after second immunization and then switched to the Th1 and Th2 balance after third immunization. In contrast, when the LCMV NP CD8(+) T cell epitope was presented, the level of Th2 immune response was higher than that of Th1 after both second and third immunization. CONCLUSION: Attenuated Salmonella can effectively deliver the CD8(+) T cell epitopes and induce specific cellular immune responses. The results provide useful information for developing attenuated bacteria as novel vectors.

Animals↗