ObjectiveTo investigate whether lysyl oxidase(LOX) has significant relation to persistent atrial fibrillation(AF) with mitral valvular diseases. MethodsWe included 184 consecutive lone mitral valvular disease patients who needed surgery in our hospital between March 2012 and February 2014. Patients who had persistent AF formed the AF group, and those who still kept sinus rhythm(SR) comprised the SR group. In the AF group, patients were separated into two groups by the subgroup of mitral valvular disease(mitral stenosis and mitral regurgitation), then formed a MS+AF group and a MR+AF group. There were 97 patients with 44 males and 53 females at age of 52.76±11.35 years in the AF group and 90 patients with 48 males and 42 females at age of 47.95±14.22 years in the SR group. Blood specimens were obtained from patients for the first time peripheral venous blood after admitted to hospital. LOX levels were measured by ELISA test kits of LOX. ResultsAF was diagnosed in 51.87%(97/187) of lone mitral valvular disease patients. Mitral stenosis patients were easy to have AF(60.31% vs. 34.43%, P<0.05). The plasma level of LOX was significantly higher in the AF group than that in the SR group(73.78±25.42 IU/L vs. 51.05±18.96 IU/L，P<0.05). In the AF group, the LOX level in the mitral stenosis group was higher than that in the mitral regurgitation group(84.21±32.15 IU/L vs. 59.74±35.21 IU/L， P<0.05). Mitral stenosis patients more frequently had a history of stroke than mitral regurgitation patients did. AF correlated significantly with the level of LOX(r=0.124， P=0.036) and left atrial dimension(r=0.531，P=0.042). ConclusionWe validate and extend the hypothesis that increasing LOX level predicts an increasing risk of AF in mitral valvular diseases. Lysine oxidase is a potential diagnostic biomarker for AF. It is expressed significantly in mitral stenosis patients with AF especially.
China is the country with high incidence of high myopia in the world. High myopia can cause severe vision impairment. So far, there is no effective treatment for high myopia in clinic. Scleral collagen cross-linking surgery has been proven to be effective in preventing animal eye axial elongation in vitro and in vivo. However, the influence of posterior scleral collagen cross-linking on the deformation of the whole eyeball is still unclear. In this study, finite element simulation were used to analyze the changes of eyeball shape and the position of light casting on the retina after posterior sclera cross-linking, and the mathematical algorithm was written to verify their similarity. The results showed that the shape of the whole eyeball was still very similar before and after cross-linking, and the diopter of the eyeball after cross-linking had little change, which had almost no effect on the position of light projection on the retina. Our results indicate that posterior sclera cross-linking wouldn’t lead to distortion to the optometry, that is, the increase of elastic modulus in local scleral tissue after cross-linking wouldn’t cause new problem of optometry and vision.
Decellularized tissue engineering scaffolds appear to have the properties of similar structure and mechanical characteristics to native tissues，good biocompatibility，suitability for cell adhesion，growth and angiogenesis induction，and non-immunogenicity. Genipin has anti-inflammatory，antithrombotic and antioxidative features which can considerably suppress vascular and endothelial inflammatory activation，increase mechanical strength of biological scaffolds，inhibit inflammatory response and decrease degradation rate of biological scaffolds. By cross-linking with decellularized matrices，Genipin can further improve corresponding performance of tissue engineering matrices，which is very helpful to promote the application of tissue engineering into clinical practice of cardiothoracic surgery. This review focuses on recent research process and possible prospects of Genipin cross-linking in tissue engineering in the field of cardiothoracic surgery.
Poly(styrene-block-isobutylene-block-styrene) (SIBS) and its crosslinked product crosslinked polyisobutylene (xPIB) are a kind of novel thermoplastic elastomer. They have excellent biocompatibility and stability, which are suitable for long-term implantation in human body. At present, SIBS is widely used in cardiovascular diseases, and also has preliminary application in ophthalmology. This article reviews the application and research progress of SIBS and xPIB in ophthalmic glaucoma minimally drainage tube material, intraocular lens material, new sclera buckle material and orbital defect filler, with a view of providing reference for the clinical application of such biomedical materials in ophthalmology.
Abstract: Objective Using Amplex red fluorometric assay to detect the lysyl oxidase (LOX) enzyme activity in tissue engineered heart valve (TEHV). Methods Porcine aortic valves were decellularized with trypsin+ethylene diaminetetraacetic acid(EDTA), TritonX-100, and RNaseⅠ＋DNaseⅠ, then they were seeded by myo-fibroblasts that harvested from rats. Then they were fed with Dulbecco’s modified Eagle medium (DMEM) which contained high glucose for 27 days, they were fed with phenol red-free and serumfree DMEM for 24 hours, and the medium was harvested and used for LOX enzyme activity assays with the Amplex red fluorometric assay. And reverse transcription-polymerase chain reaction (RT-PCR) technique was used to analyze the expression of LOXmRNA in TEHV. Results All the samples produced measurable amounts of active LOX enzyme. The fluorescence units were 45.60±1.66, and the corresponding concentration of LOX enzyme were 0.123±0.003μg/ml. At the same time, all the samples expressed LOXmRNA. The expression of LOXmRNA was corresponding to the results of the Amplex red fluorometric assay. Conclusion It is feasible to detect the LOX enzyme activity in TEHV with the Amplex red fluorometric assay. And this assay gives a way to reflect that LOX plays an important role in collagen cross-linking of extracellar matrix in TEHV.
This study was to explore a better three-dimensional (3-D) culture method of chondrocyte. The interpenetrating network (IPN) gel beads were developed through a photo-cross linking reaction with mixed barium ions and calcium ions at the ratio of 5:5 with the methacrylic alginate (MA), which was a chemically conjugated alginate with methacrylic groups. The second generation of primary cartilage cells was encapsulated in the MA gel beads for three weeks. In the designated timing, HE stain, Alamar blue method and Scanning electron microscopic were used to determine the cartilage cells growth, proliferation and the cell distribution in the scaffolds, respectively. The expression of typeⅡcollagen was investigated by an immunohistochemistry assay and the glycosaminoglycan content was quantitatively evaluated with the spectrophotometry of 1, 9 dimethylene blue assay. Compared to the alginate control group, the deposition of glycosaminoglycan was significantly upregulated in IPN-MA gel beads with higher cell proliferation. The secretion of extracellular matrix and proliferation of chondrocyte in methacrylic alginate gel beads were higher than that in Alginate beads. Cells were able to attach, to grow well on the scaffolds under scanning electron microscopy. The result of immunohistochemistry staining of collagen typeⅡwas positive, confirming the maintenance of chondrocyte phenotype in methacrylic alginate gel beads. This study shows a great potential for three-dimensional culture of cartilage.
OBJECTIVE: To review the recent advances of hyaluronic acid and its derivatives in medical application. METHODS: Recent original articles related to hyaluronan derivatives and their medical applications were retrieved extensively. RESULTS: Hyaluronic acid and its derivatives play important roles in visosurgery, arthritis therapy, prevention of adhesion, drug delivery, soft-tissue dilation, and percutaneous embolization. CONCLUSION: Development of hyaluronan derivatives may widen their medical application.
Abstract: Objective To observe the physical characteristics of decellularized porcine pulmonary valved conduits crosslinked by carbodiimide (EDC). Methods [WTBZ]Twenty porcine pulmonary valved arteries were mobilized on relative asepsis condition. They were cut longitudinally into three samples at the junction position of pulmonary valve (every sample was comprised of a part of the pulmonary conduit wall and the corresponding valve). The samples were randomly divided into three groups by lotdrawing method. Group A was the control group which was made up of the fresh porcine arterial valved conduit samples without any other treatments. Group B was comprised of porcine pulmonary samples decellularized by trypsindetergent digestion. Group Cincluded the decellularized porcine pulmonary samples crosslinked by EDC. We observed the water content, thickness, tensile strength, and shrinkage temperature of all the samples, based on which the physical characeteristics of these samples were analyzed. Results [WTBZ]Complete cellfree-pulmonary conduit matrix was achieved by trypsindetergent digestion. Compared with group A, in group B, the water content of pulmonary wall was significantly higher (P=0.000), while the water content of pulmonary valve was not significantly different; the thickness of pulmonary wall and valve (P=0.000，0.000) and tensile strength of pulmonary wall and valve (Plt;0.01） was significantly lower, while shrinkage temperature was not significantly different. Compared with group B, in group C, the water content of pulmonary wall was significantly lower (P=0.000), while the water content of pulmonary valve, and the thickness of pulmonary wall and valve were not significantly different; the tensile strength of pulmonary wall (Plt;0.01) and valve (P=0.000), and the shrinkage temperature of them (P=0.000, 0.000) were significantly higher. Compared with group A, in group C, the water content of pulmonary wall and valve, and the tensile strength of them were not statistically different, while the thickness of pulmonary wall and valve was significantly lower (P=0.000, 0.000), and the shrinkage temperature of them was significantly higher (P=0.000, 0.000). Conclusion [WTBZ]EDC crosslinking method is available for treating decellularized porcine pulmonary valved conduits in order to enhance its tensile strength, and decrease water content of pulmonary wall.
Objective To manufacture fish swim bladder membrane material by crosslinking techniques, and to explore its physical and chemical properties and cytotoxicity. Methods After decellularization, the swim bladders were randomly divided into two groups. The swim bladders were treated with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC)/N-hydroxysuccinimide (NHS) crosslinking method, surface hole making, and freeze-drying in crosslinking group, and only surface hole making and freeze-drying in non-crosslinking group. The physical and chemical properties of the materials were observed, including microstructure by scanning electron microscopy (SEM), mechanical properties (tensile strength and breaking elongation) by universal tensile machine, hydrophilicity by contact angle measuring instrument, porosity by ethanol infiltration method, degradation performance in vitro and thermal stability test, and the components of materials by infrared spectrum analysis. Mouse fibroblasts (L929) were cultured with the extracts of two groups of materials in order to determine the cytotoxicity of materials by using cell counting kit 8 (CCK-8) method. Results The porous structure and rough surface of materials were observed by SEM. Compared with the non-crosslinking group, the tensile stress of the crosslinking group was higher, the breaking elongation was lower, and the porosity increased, showing significant differences (P<0.05). There was no significant difference in contact angle between the two groups (P>0.05). The degradation was faster within the first 7 days and then tended to be smooth in the two groups. But the degradation rates of crosslinking group were significantly lower than those of non-crosslinking group (P<0.05). Differential scanning calorimeter showed that the denaturation temperature of the crosslinking group was (75.2±1.3)℃, which was significantly higher than that of the non-crosslinking group [(68.5±0.4)℃] (t=4.586, P=0.002). Compared with the non-crosslinking group, the crosslinking group produced new C=O bond and N-H bond, and no other new groups were introduced into the cross-linking group. CCK-8 method showed that the absorbance values of the crosslinking group and the non-crosslinking group were not significant when compared with the positive control group (P>0.05). Conclusion The fish swim bladder membrane obtained by crosslinking treatment with EDC/NHS method has good physical and chemical properties, no cytotoxicity, and is expected to be used as a dura mater repair material.
【Abstract】ObjectiveTo introduce a new approach for site-specific conjugation of Fab’ fragments of mouse monoclonal antibody (MoAb) to a bifunctional chelator 6-〔p-(bromoacetamido)benzyl〕-1,4,8,11 -tetraazacyclo-tetradecane-N,N′,N″,N-tetraacetic acid (BAT).MethodsFab’ fragments of B43 MoAb were obtained by a simple twostep method： 1, stable F(ab’)2 was produced by pepsin treatment of B43 MoAb. 2, Fab’ was obtained by reduction of the F(ab’)2 with cysteine. Fab’ fragments were directly conjugated with BAT. ResultsFab’ contained about 1.8 free thiol per molecule. The conjugation rate was 74% and each Fab’ fragment carried 1.28 BAT. The F(ab’)2, Fab’ and Fab’-BAT all maintained good biologic activity. ConclusionThis study may provide a simple and efficient method conjugating of MoAb Fab’ fragments to BAT.