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Biomedical subjects

Zhi-fei Xu

Publications and source records attributed to Zhi-fei Xu.

6 recordsLinked to original sources
PubMed2006

[Experimental study of degradable chitin long fiber reinforced polycaprolactone for reconstruction of chest wall defects].

OBJECTIVE: To investigate the application of a novel degradable biomaterial as a chest wall prosthesis and provide valuable scientific basis for clinical application. METHODS: Preparation of chitin long fiber reinforced polycaprolactone (PCL) by means of melt blending and modeling. Full-thickness chest wall defects of 10 cm x 8 cm was created in 10 dogs and then repaired with long chitin fiber reinforced PCL artificial rib in 8 dogs (tested group) and Marlex mesh in 2 dogs (control group). It was dynamically observed that the situation of the implanted chest wall prosthesis and the progress of the regeneration of the chest wall tissue postoperatively. RESULTS: No operative and perioperative deaths were observed in all experimental dogs. In tested group, slight paradoxical respiration occurred in 2 dogs and could not be seen in 2 weeks. No chest wall subsidence and infection occurred. New bone tissue obviously regenerated around both resection ends of the ribs and integrated tightly with artificial ribs. In control group, there were evidently paradoxical respiration and chest wall subsidence. Marlex mesh folded and was enveloped by fibrous tissue. CONCLUSION: Degradable chitin long fiber reinforced PCL can provide effective support to chest walls and is a practicable material for chest wall reconstruction.

Animals↗
PubMed2004

[Experimental study on the reconstruction of circumferential tracheal defects with novel prosthesis].

OBJECTIVE: To investigate the feasibility of using new tracheal prosthesis made of biomaterials to replace extensive circumferential tracheal defects in mongrel dogs. METHODS: Three types of tracheal prostheses were developed, whose basic skeleton of tubular mesh was knitted with polypropylene monofilament and poly (lactic-co-glycolic acid) fiber. The inner side of type-I tubular mesh was first coated with polyurethane solution and then with collagen. The exterior of type-I was then immobilized with collagen-hydroxyapatite composites. In contrast, the internal and external walls of type-II were coated with polyurethane solution, which produced a prosthesis similar to a nonporous one, while type-III was coated only with collagen solution. Surgical resection and replacement of a segment of the cervical trachea was performed in 16 adult mongrel dogs. The efficacy of the implanted prosthesis periodically evaluated postoperatively. RESULTS: In group A, only one died from prosthetic dehiscence, another from anastomotic leakage, and the others had uneventful postoperative courses. The implanted prosthesis was completely incorporated with the recipient trachea, where different length of reepithelialization occurred on the luminal surface of the reconstructed trachea. Macroscopic examination showed scattered and different sizes of neo-ossification surrounding the implanted prosthesis. The prosthesis was roentgenopaque when exposed to routine X rays. In contrast, a relatively high number of complications occurred postoperatively in group B and C. CONCLUSION: Type-I tracheal prosthesis may be used effectively for long-segment circumferential tracheal replacement, and appears very promising for clinical application, with further improvements in promoting the epithelialization.

Animals↗
PubMed2003

[Experimental study on a novel esophageal prosthesis made of composite biomaterials].

OBJECTIVE: To design and develop a novel esophageal prosthesis by selecting appropriate biomaterials, developing special manufacturing techniques, and investigating the feasibility of replacement of cervical esophagus in mongrel dogs. METHODS: In accordance with the requirements of ideal esophageal substitutes, we designed a new type of esophageal prostheses. The inner stent were made with polyurethane of medical grade, and the outer surface of the prosthesis was coated with collagen-chitosan sponge. The silicone tube was used as a control. Thirteen adult mongrel dogs that were divided into two groups were used to establish the experimental models. RESULTS: In the experimental group (n = 8), the esophageal prostheses were completely incorporated with the native esophagus and adherent to the surrounding host connective tissues. Epithelial linings of varying degrees were formed on the luminal surface, and complete epithelization was seen in 1 month postoperatively. The granulation at the sites of the anastomosis in this group was less significant than that of the control group. One dog has been surviving for 12 months up to now without any complications. In the control group (n = 5), esophageal epithelial was not observed on the luminal surface, constriction of the regenerated esophagus progressed and all the dogs died within 2 months after operation. CONCLUSION: These observations suggest that this esophageal prosthesis made of composite biomaterials has high biocompatibility and potential for long-segment esophageal reconstruction, which is promising for the clinical repair of esophageal defects.

Absorbable Implants↗
PubMed2003

[Reconstruction of a cervical esophagus segment with an artificial prosthesis by use of a polyurethane stent covered with collagen-chitosan sponge in dogs].

OBJECTIVE: To repair esophageal defects with an artificial prosthesis composed of biodegradable materials and nonbiodegradable materials, which is gradually replaced by host tissue. METHODS: The artificial esophagus was a two-layer tube consisting of a chitosan-collagen sponge and an inner polyurethane stent with a diameter of 20 mm and a length of 50 mm. We used the artificial esophagus to replace 5 cm esophageal defects in group I (five dogs) and in group II (ten dogs), and nutritional support was given after operation. The inner polyurethane stent was removed after 2 weeks in group I and after 4 weeks in group II endoscopically and epithelization of the regenerated esophagus was observed by histologic examination and transmission electron microscope. RESULTS: In group I, the polyurethane stent was removed after 2 weeks, and partial regeneration of esophageal epithelial was observed; and constriction of the regenerated esophagus progressed and the dogs became unable to swallow after 4 weeks. In group II, the polyurethane stent was removed after 4 weeks, highly regenerated esophageal tissue successfully replaced the defect and complete epithelization of the regenerated esophagus was observed. After 12 weeks, complete regeneration of esophageal mucosa structures, including mucosal smooth muscle and mucosal glands and partial regeneration of esophageal muscle tissue were observed. CONCLUSION: Esophageal high-order structures can be regenerated and provided a temporary stent and support by polyurethane stent and an adequate three-dimensional structure for 4 weeks by collagen-chitosan sponge.

Absorbable Implants↗