Biomedical subjects

Zhi-Gang Liu

Publications and source records attributed to Zhi-Gang Liu.

7 recordsLinked to original sources

PubMed2006

One-stage total or subtotal aortic replacement.

BACKGROUND: The goal of total aortic resection surgery is to correct the extensive or multiple sites of aortic pathology, which involves the entire length of the vessel. This study describes our experience in this operation at Fuwai Cardiovascular Hospital. METHODS: From February 2004 to October 2005, thirteen patients with Marfan syndrome underwent one-stage total or subtotal aortic replacement for aortic dissection or aortic aneurysms. Four patients received subtotal aortic replacement (ascending aorta to the abdominal aorta). Nine patients underwent total aortic replacement (ascending aorta to the aortic bifurcation). Operations were performed under circulatory arrest with profound hypothermia. Patients were opened with a mid-sternotomy and a thoracoabdominal incision. Extracorporeal circulation was instituted with two arterial cannulae and a single venous cannula in the right atrium. During cooling, the ascending aorta or aortic root was replaced. At the nasopharyngeal temperature of 20 degrees C, the aortic arch was replaced with selective antegrade cerebral perfusion. After brain reperfusion, staged aortic occlusions allowed for replacement of descending thoracic and abdominal aorta. Intercostal, visceral, and renal arteries were anastomosed to the graft. RESULTS: There was no operative or early postoperative death. One case of postoperative complication was noted for cerebral infarction secondary to embolism. Spinal neurologic deficits did not occur. At the last follow-up, ranging from 4 to 24 months postoperatively, all 13 patients were alive and had good functional status. CONCLUSIONS: One-stage total or subtotal aortic replacement for treatment of extensive aortic disease is feasible with acceptable surgical risks and satisfactory results. It can eliminate the risk of remnant aortic aneurysm rupture in staged total aortic replacement.

Adult↗

PubMed2006

[Study on structures of blattela germanica allergen, Bla g 2 expressed by eukaryotic and prokaryotic vectors using fluorescence and CD spectra].

The recombinant allergen, Bla g 2, was expressed by prokaryotic vector E. coli and eukaryotic vector P. Pastoris. The different structures and configurations of the Bla g 2 from E. coli and P. Pastoris were studied by fluorescence and circular dichroism. The secondary structures of Bla g 2 in solution, and the composition besides the type of its tertiary structure were proposed. These studies help understand the differences between prokaryotic and eukaryotic expression systems, reveal the relationship between the structure and the function of Bla g 2, and improve the production of this significant allergen.

Allergens↗

PubMed2005

Should the "elephant trunk" be skeletonized? Total arch replacement combined with stented elephant trunk implantation for Stanford type A aortic dissection.

OBJECTIVES: To eliminate the residual false lumen in the descending thoracic aorta and improve long-term outcomes of surgical intervention for Stanford type A aortic dissection, we performed the skeletonized "elephant trunk" procedure in the ascending aorta and aortic arch replacement combined with transaortic stented graft implantation into the descending aorta for both acute and chronic type A aortic dissection, and the short-term results were compared. METHODS: Between April 2003 and November 2004, 60 consecutive patients (mean age, 53 +/- 16.7; approximate range, 28-78 years) with acute (n = 36) or chronic (n = 24) type A aortic dissection underwent this procedure. Right axillary artery cannulation was used for cardiopulmonary bypass and selected cerebral perfusion. The stented graft, a 10-cm-long woven Dacron graft with a self-expandable stent, was implanted through the aortic arch during hypothermic circulatory arrest. Enhanced electric beam computed tomography was performed in each patient before discharge, 3 months after the operation, and once each year thereafter to evaluate the postoperative time course of the residual false lumen. RESULTS: Cardiopulmonary bypass time was 166 +/- 38 minutes, and average selective cerebral perfusion and lower body arrest time was 30 +/- 15 minutes. The in-hospital mortality was 3.3% (2/60). Thrombus obliteration of the residual false lumen in the descending thoracic aorta was observed in 92% and 85% of the acute and chronic aortic dissections, respectively, 3 months postoperatively. There was no late death during follow-up. CONCLUSIONS: The skeletonized elephant trunk procedure is an effective way of closing the residual false lumen of the descending aorta and might contribute to better long-term outcomes for both acute and chronic type A aortic dissection.

Acute Disease↗

PubMed2005

Biophysical studies of a ruthenium(II) polypyridyl complex binding to DNA and RNA prove that nucleic acid structure has significant effects on binding behaviors.

The interactions of a metal complex [Ru(phen)(2)PMIP](2+) {Ru=ruthenium, phen=1,10-phenanthroline, PMIP=2-(4-methylphenyl)imidazo[4,5-f]1,10-phenanthroline} with yeast tRNA and calf thymus DNA (CT DNA) have been investigated comparatively by UV-vis spectroscopy, fluorescence spectroscopy, viscosity measurements, isothermal titration calorimetry (ITC), as well as equilibrium dialysis and circular dichroism (CD). Spectroscopic studies together with ITC and viscosity measurements indicate that both binding modes of the Ru(II) polypyridyl complex to yeast tRNA and CT DNA are intercalation and yeast tRNA binding of the complex is stronger than CT DNA binding. ITC experiments show that the interaction of the complex with yeast tRNA is driven by a moderately favorable enthalpy decrease in combination with a moderately favorable entropy increase, while the binding of the complex to CT DNA is driven by a large favorable enthalpy decrease with a less favorable entropy increase. The results from equilibrium dialysis and CD suggest that both interactions are enantioselective and the Delta enantiomer of the complex may bind more favorably to both yeast tRNA and CT DNA than the Lambda enantiomer does, and that the complex is a better candidate for an enantioselective binder to yeast tRNA than to CT DNA. Taken together, these results indicate that the structures of nucleic acids have significant effects on the binding behaviors of metal complexes.

Base Sequence↗

PubMed2005

DNA vaccine encoding Der p 2 allergen generates immunologic protection in recombinant Der p 2 allergen-induced allergic airway inflammation mice model.

BACKGROUND: DNA immunization is a promising novel type of immunotherapy against allergy. An estimated 79.2% patients with asthma, wheezing and/or rhinitis suffer from Dermatophagoides pteronyssinus group 2 (Der p 2) allegen. The aim of the present study was to determine whether DNA vaccine encoding Der p 2 could generate immunologic protection in recombinant Der p 2 (rDer p 2) allergen-induced allergic airway inflammation mice model and to understand the role of DNA vaccination in specific-allergen immunotherapy for asthma. METHODS: After DNA vaccination, BALB/c mice were sensitized by intraperitoneal injection (i.p) and challenged by intranasal instillation of rDer p 2. The lung tissues were assessed using hematoxylin and eosin. Mucus-producing goblet cells were identifed using periodic acid-Schiff (PAS)/alcian blue. The total cell number and composition of bronchoalveolar lavage samples were determined. The levels of the cytokines IL-4 and IFN-gamma, as well as IgE and IgG2a in the serum were determined by enzyme-linked immunosorbent assay. Allergen-specific IL-4 and IFN-gamma production by spleen cells were also measured by enzyme-linked immunosorbent assay. Expression of signal transducer and activator of transcription 6 (STAT6) in splenocytes were determined by Western blot. RESULTS: DNA vaccine encoding Der p 2 allergen inhibited extensive infiltration of inflammatory cells and production of mucin induced by allergen. The influx of eosinophils into the lung interstitium was significantly reduced after administration of DNA vaccine. Significant reductions of IL-4 and increase in levels of IFN-gamma in bronchoalveolar lavage fluid were observed. The allergen-specific IgE was markedly decreased in mice receiving DNA vaccination. Allergen could induce higher IFN-gamma, weaker IL-4 in cultured spleen cells from mice receiving DNA vaccine. DNA vaccination inhibited STAT6 expression of spleen cells induced by allergen. CONCLUSION: These results indicated that DNA vaccine encoding Der p 2 allergen generates immunologic protection in recombinant Der p 2 allergen-induced allergic airway inflammation mice model with regulating the immune response towards a Th1-type reaction.

Animals↗

PubMed2002

[In vitro molecular evolution of humanized mouse ScFv specific against human cross-linked fibrin].

In early work at our laboratory, a mouse ScFv All specific against human cross-linked fibrin was picked out by using phage displaying technique, and it was useful in prepareing targeting thrombolytic agent. To reduce its immunogenicity, All was humanized according to the surface reshaping approach. In order to increase the affinity and specifity of humanized ScFv, the Mixed HCDR3 and LCDR3 library was constructed and selected, and five different humanized ScFv with better affinity or specifity than humanized ScFv were identified, but the affinity of these five humanized scFvs was still lower than parent mouse scFv All. In this study, in order to further increase the affinity of humanized scFv, the identified five different CDR3 mutant of humanized ScFvs were mutated and reassembled with the methods of error-prone PCR and DNA shuffling, then the shuffled ScFvs were cloned into plasmid pHB-1 HSCFV to construct ScFv library of 10(5). The ScFv library was displayed on the surface of phage and panned with antigen DD, then five ScFvs with better affinity or specifity were identified by using ScFv-alkaline phosphatase detection system which was established in our laboratory. Based on identified five better ScFv, the second round error-prone PCR and DNA shuffling program was taken out, a ScFv library of 10(6) was constructed and selected as before. And four humanized ScFv that had evidently better affinity than parent mouse ScFv was identified. This work laid a foundation for further research of targeting thrombolitic agent with low immunogenicity.

Animals↗

PubMed2002

[The functional expression of humanized ScFv-urokinase fusion protein in Escherichia coli].

The fusion protein of Humanized mouse anti-human fibrin ScFv and the low molecular weight urokinase (IIn-UK) contained seven disulfide bonds and formed inclusion body while expressing in normal E. coli strain. By coexpressing DsbC and using the special E. coli strain Origami(DE3) which was trxB/gor double mutant, the fusion protein IIn-UK was functionally expressed in the cytoplasm of E. coli. The expressed fusion protein in the soluble fraction was purified by using affinity chromatography specific against urokinase. The purified fusion protein could combine the thrombus in vitro, and the specific activity of urokinase reached 80,000 IU/mg fusion protein. The result showed that the fusion protein retained the activity of two moieties, and this study laid a foundation for further research of targeting thrombolytic agent.

Animals↗