Biomedical subjects

Tingwu Qin

Publications and source records attributed to Tingwu Qin.

22 records · Page 2Linked to original sources

PubMed2002

[Characteristics of tenocyte adhesion to biologically-modified surface of polymer].

In this study we examined the in vitro characteristics of tenocyte adhesion to biologically-modified surface of polymer. Polylactic-co-glycolic acid (PLGA) 85/15 films were prepared by a solvent-casting technique. Each film was adhered onto the bottom of a chamber. The film was precoated with poly-D-lysine (PDL), and then coated with serum-free F12 medium containing various concentrations of fibronectin (FN), type I collagen (CN I), and insulin-like growth factor1 (IGF-1). The monoclonal antibodies (to FN and to CN I) with various dilutions were used to inhibit attachment of tenocytes to surface precoated with FN or CN I. Human embryonic tendon cells (HETCs) and transformed human embryonic tendon cells (THETCs) were used as the seeding cells. The system used for the measurement of adhesion force was the micropipette aspiration experiment system. The micropipette was manipulated to aspirate a small portion of the tenocyte body by using a small aspiration pressure. Then the pipette was pulled away from the adhesion area by micromanipulation. The minimum force required to detach the tenocyte from the substrate was defined as the adhesion force. The results showed that modification of FN or CN I by precoating significantly enhanced attachment of tenocytes to surface of polymer (P < 0.05). As antibodies to FN or CN I were added to a polymer film precoated with FN or CN I, the adhesion force decreased significantly (P < 0.05). We concluded that the specific adhesion forces of tenocytes to extracellular matrix adhesion proteins (FN and CN I) had coordinated action and showed good dependence on their precoating concentrations, and were inhibited by the antibodies to these adhesion proteins. Films precoated with IGF-1 strongly accelerated the adhesion of tenocytes to polymer. These results indicate that the specific adhesion of tenocytes to polymer can be promoted by coating extracellular matrix adhesive proteins and insulin-like growth factor1. It is of great importance to construct tissue-engineered tendon.

Biocompatible Materials↗

PubMed2002

[Experimental reconstruction of extensive anterior defect of rabbit trachea with the use of free auricular cartilage].

OBJECTIVES: To determine whether free auricular cartilage grafts can be used to reconstruct the extensive anterior defect of rabbit trachea and observe the difference between autograft and allograft. METHODS: Twenty New Zealand white rabbits were divided into autograft group (n = 10) and allograft group (n = 10). All grafts were taken from the right auricle, and defect included 8 to 10 rings of trachea. The gross morphorlogical features, endoscopic examinations, biomechanic determinations and histological findings of grafts were assessed at 1,2,4,8 and 12 weeks after operation. RESULTS: Eighteen rabbits survived. Mild tracheal stenosis was observed under endoscope. The maximum stress per mm at 0,4,8 and 12 weeks was 2.54 +/- 0.19, 1.31 +/- 0.21, 1.72 +/- 0.22 and 1.96 +/- 0.08 kPa/mm, respectively. Histological analysis revealed that the viable chondrocytes and neochondrocytes at 12 weeks accounted for 62.0% +/- 3.45%, 65.89% +/- 48% in the autograft group and 60.1% +/- 3.98%, 55.20% +/- 7.57% in the allograft group. No marked immunological differences between the auto- and allograft groups were noted. CONCLUSIONS: Free auricular cartilage can be used to reconstruct the extensive anterior defect of trachea in both auto- and allo-transplantations.

Animals↗

PubMed2002

[Initial study on three-dimensional culture of tenocytes under cyclic mechanical stretch].

OBJECTIVE: To detect the effect of mechanical stretch on shape, alignment, proliferation, and metabolism of tendon cells maintained in three-dimensional culture. METHODS: A cyclic mechanical strain apparatus for three-dimensional cell cultures was developed. Based on the apparatus, a specific stretch pattern (10% elongation, 12 stretches/min for 15 min of each hour) was applied to tenocytes-scaffolding composites. RESULTS: Initial studies demonstrated that the stretch-mediated effects on cell division, DNA synthesis, and metabolism in such cultures were influenced by the amplitude, frequency, periodicity, and duration of the applied stretch. After 48 hours' exposure to the stretch, the cell number and [3H] thymidine incorporation into DNA were increased, compared with those of the nonstretched controls(P < 0.05). Under the stretch pattern, the shape of cells changed to oblate and spread to the direction of the stretch. The cyclic stretch also caused an increase in collagen synthesis by tendon cells (P < 0.05), which was predominant in type I. CONCLUSION: Cyclic mechanical stretches act directly to stimulate tendon cell growth and these results are compatible with a significant role for stretch in tissue-engineered tendon construction.

Cell Division↗

PubMed2002

[Tissue-engineered auricled cartilage: an experimental study].

OBJECTIVE: To study the feasibility of engineering auricled neocartilage with chitosan/polylacticacid-polycrylactone (PLA-PCL) network scaffolds and to search the difference between dynamic and silent chondrocytal culture techniques. METHODS: Chondrocytes from auricled cartilage of 4 weeks old New Zealand White rabbit were seeded onto chitosan/PLA-PCL network. Ten cell-polymer scaffolds were divided into two groups: dynamic group (n1 = 5) with rotating bioreactors and silent group (n2 = 5) with ordinary dishes to culture. Using scan electroscope, grossly histological and immunohistological techniques, the morphological evaluation was done individually at 1st week in vitro, 4th and 8th week in vivo. RESULTS: Chondrocytes adhered and grew up well on the network, but more quantities of chondrocytes, Glycoaminoglygan (GAG) and type II collagen were found in dynamic group. There was an obvious difference between dynamic and silent group (P < 0.05). CONCLUSION: Chitosan/PLA-PCL network scaffold is good for adhesions and growth of chondrocytes. Furthermore, dynamic cell culture method is better than silent method for formation of neocartilage.

Animals↗