Experimental study on mechanical properties of decellularized porcine aortic valve and effects of precoating methods of biological scaffold on histocompatibility / 中华外科杂志

<p><b>OBJECTIVE</b>To observe the mechanical properties of decellularized porcine aortic valve, and to explore the effects of precoating methods of biological scaffold on histocompatibility.</p><p><b>METHODS</b>Fresh porcine aortic valves were decellularized using trypsin, TritonX-100 and nuclease. Treated valves were evaluated by light microscopy, scanning electron microscopy (SEM) and mechanical test. Three groups of scaffold were precoated with phosphate buffered saline (PBS), poly-L-lysine (PLL) and fetal bovine serum (FBS) respectively. Myofibroblasts were seeded onto each scaffold. Light and electron microscopic observation was performed and MTT test was used to examine efficiency of cell attachment.</p><p><b>RESULTS</b>HE stain and SEM showed that cells were almost absent in the treated leaflet. The wave-like collagen together with the whole three-dimensional structure was maintained. Compared with normal valves, the Max-load, Max-stress and elastic modulus decreased while the Max-strain increased (P<0.05). The result of MTT test showed more cells were attached on the valves treated with FBS compared to the other two groups. Histological investigations also confirm that the high degree of cell attachment on the valves precoated with FBS (F=129.26, P=0.000).</p><p><b>CONCLUSIONS</b>Enzyme combined with detergent and nucleases can remove cells from porcine aortic valves. Meanwhile the mechanical properties of these valves may be altered. Precoating porcine aortic valve with FBS is an effective method to improve cell attachment, growth and increasing.</p>

Association between ADAM33 gene polymorphism and bronchial asthma in South China Han population / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the association between the polymorphism of T(1) locus allele in ADAM33 gene and bronchial asthma in South China Han population.</p><p><b>METHODS</b>Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and DNA sequencing were used to determine the polymorphism of T(1) locus allele in ADAM33 gene in 160 unrelated patients with asthma and 95 unrelated healthy controls from South China Han population.</p><p><b>RESULTS</b>No significant difference was found in T(1) locus allele distribution frequency in populations of UK, US, Germany, Korea, and South China (Chi(2)=9.085, P=0.109). The frequencies of the genotypes (TT, TC, CC) were 80.6% (n=129), 16.9% (n=27) and 2.5% (n=4) in the 160 asthmatic patients and 94.7% (n=90), 3.2% (n=3) and 2.1% (n= 2) in the 95 controls, respectively, showing a significant difference in the distribution of the genotypes (TT, TC, CC ) between asthmatic patients and healthy controls (Chi(2)=10.955, P<0.05). The frequencies of the alleles (T, C) were 0.891 and 0.109 in the asthmatic patients and 0.963 and 0.037 in the controls, respectively, showing also a significant difference in the allele frequency between them (Chi square =8.299, P<0.05). The presence of C allele of ADAM33 gene T1 locus was found to be a greater risk factor in asthmatic patients than in the healthy controls. The odds ratio (OR) of TC and TC+CC were 6.279 (1.849-21.328) and 4.326 (1.620-11.550), respectively, with P value of 0.001 and 0.002, respectively, in comparison with TT genotype.</p><p><b>CONCLUSION</b>The polymorphism of T(1) locus allele in ADAM33 gene is associated with the susceptibility to asthma in South China Han population.</p>