Examination and discriminant analysis of corneal biomechanics with CorVis ST in keratoconus and subclinical keratoconus / 北京大学学报(医学版)

OBJECTIVE@#To compare the corneal biomechanical properties among keratoconus, subclinical keratoconus and normal corneas by using CorVis ST, and to estimate the effect of these biomechanical indices in discriminating keratoconus and subclinical keratoconus from normal.@*METHODS@#A total of 76 eyes of 67 subjects were enrolled and divided into three groups. Keratoconus group included 24 eyes from 17 patients, subclinical keratoconus group included 12 eyes from 12 patients and normal group included 40 normal eyes from 40 subjects．All the eyes were assessed with CorVis ST and ten biomechanical parameters, intraocular pressure (IOP) and central corneal thickness (CCT) were obtained from this machine. The discrimination of biomechanical characteristic of the three groups based on the all indices was reflected by discriminant analysis and the Fisher discriminant function was established.@*RESULTS@#The values of corneal biomechanics of keratoconus, subclinical keratoconus, normal eyes were increased in sequence, except for three indices: the second applamation time (A2T), time taken to reach highest concavity (HCT) and maximum corneal velocity during the first applanation (Vin). Three sets of data were among a statistically significant difference (P<0.05). There were statistically significant differences (P<0.05) between any two groups by comparing with such two indices: radius value of central concave curvature at highest concavity (HCR) and CCT. The grades of the three groups were obvious, evaluated by the discriminant function. The accuracy of reevaluation was 85% by validation method. The biggest contribution of indices in discriminant function was given by such four indices in sequence: CCT, HCR, maximum deformation amplitude of highest concavity (HCDA) and maximum corneal velocity during the second applanation (Vout).@*CONCLUSION@#The corneal biomechanical properties of keratoconus and subclinical keratoconus were decreased compared with normal eyes. The biomechanical parameters based on CorVis ST showed a good performance for discriminating among keratoconus, subclinical keratoconus and normal corneas.

Effect of collagen crosslinking on porcine sclera with different methods / 中华实验眼科杂志

Background Chemical crosslinking agent can be used to strengthen the intensity of sclera tissue,but the intensity of the sclera may be influenced by different crosslinking methods.Objective The aim of this study was to compare the effectiveness of collagen crosslinking on porcine sclera between whole-eye crosslinking method and scleral strip crosslinking method.Methods Whole-eye crosslinking or sclera strip crosslinking was performed on 70 fresh porcine eyeballs in five groups using 1％ genipin,1％ glutaraldehyde or PBS respectively for 40 minutes.After crosslinking,10 sclera strips with l0 mm×4 mm from the temporal lateral were prepared in every group for the stress-strain measurement using a Instron5848 microtester,and the other 4 scleral strips in each group were extracted for the thermal shrinkage temperature test.Results Biomechanical property test reveled that the elastic modulus value of sclera strips reduced by 70.0％-82.8％ in the whole-eye crosslinking method group compared with scleral stip crosslinking method group after treated with 1％ genipin ((8.98 ± 1.81) MPa vs.(10.85 ± 1.83) MPa,t =3.375,P =0.003)) and 1％ glutaraldehyde((12.78 ±2.91) MPa vs.(18.25 ±5.16) MPa,t =4.007,P =0.001)) ;The tensile stress of whole-eye crosslinking method group was 54.9％-90.1％ of scleral stips method group,showing significant decline after corsslinked of whole-eye in 5％,10％,15％ and 20％ strain conditions (all P ＜ 0.05).Thermomechanics test showed that the thermal shrinkage temperature was lower in the whole-eye crosslinking group compared with scleral stip crosslinking group after treated with both 1％ genipin ((68.8 ±0.9)℃ vs.(74.8± 1.3)℃,t=11.129,P=0.000)) and 1％ glutaraldehyde((73.3±0.9)℃ vs.(79.3±1.3)℃,t=11.112,P=0.000)).Conclusions Different crosslinking methods have an influence on the efficacy of collagen crosslinking on porcine sclera.Sclera strip crosslinking offers a better crosslinking intensity for selera.

Effect of recombinant Sp1 gene on the collagen expression of hypertrophic scar fibroblasts in vitro / 中华整形外科杂志

<p><b>OBJECTIVE</b>To explore the feasibility of transfecting recombinant Sp1 into hypertrophic scar fibroblasts and investigate the proliferation and collagen I, III synthesis in the transfected cells.</p><p><b>METHODS</b>Recombinant human Sp1 was transfected into hypertrophic scar fibroblasts with the karyocyte expressive vector. The expression of Sp1, collagen I, III mRNA was tested by real time PCR. The change of cell proliferation was observed with CCK8 colorimeter.</p><p><b>RESULTS</b>About 30% of transfected hypertrophic scar fibroblasts showed green fluorescence positive. The relative expression of Sp1 mRNA in transfected cells, empty-vector cell or untransfected cells group was 5.26 +/- 0.76, 1.08 +/- 0.18, 1.09 +/- 0.15, respectively, showing a significant difference between thansfected and untransfected cells or between the transfected cells and empty-vector group (P <0.01, n = 5). Expression of collagen I, III mRNA was 2.49 +/- 0.40 and 1.88 +/- 0.30 in transfected cells, 0.96 +/- 0.18 and 0.95 +/- 0.18 in empty-vector cell, and 0.97 +/- 0.15 and 0.93 +/- 0.13 in untransfected cells, respectively, showing a significant difference between thansfected and untransfected cells or between the transfected cells and empty-vector group (P < 0.01, n = 5).</p><p><b>CONCLUSIONS</b>The hypertrophic scar fibroblasts could be as the target cells of Sp1 gene transfection. Sp1 gene may play an important role in abnormal collagen metabolism in hypertrophic scar.</p>

Application of both expanded cutaneous flap and temporoparietal fascia flap in ear reconstruction with Medpor framework / 中华整形外科杂志

<p><b>OBJECTIVE</b>To investigate the feasibility and results of application of both expanded cutaneous flap and temporoparietal fascia flap in total ear reconstruction with Medpor framework.</p><p><b>METHODS</b>The main procedure consists of two stages: Stage I-skin expansion; Stage II -auricle formation consists of orientation of Medpor implant and creation of coverage for the implant by both expanded skin flap and temporoparietal fascia flap.</p><p><b>RESULTS</b>Twenty-two ears in 22 unilateral microtia patients were constructed using Medpor implants covered with both expanded cutaneous flap and temporoparietal fascia flap over the last three years, they were accepted as pleasing by the patients.</p><p><b>CONCLUSIONS</b>Application of both expanded cutaneous flap and temporoparietal fascia flap can assure no extrusion of Medpor implant in ear reconstruction. Either more, the two layers of transferred tissues will not affect the profile details of the reconstructed ear. And because the skin covering the framework and fascia is derived from mastoid region, the appearance and profile of the reconstructed auricle is true to nature and close to that of the opposite one.</p>

In vitro evaluation of biocompatibility and surface modification of 3 kinds of artificial graft material / 第二军医大学学报

Objective: To evaluate the biocompatibility of 3 kinds of artificial, biodegradable graft materials, including T20 [Poly (butylene terephthalate)-co-poly (cyclohexylene dimethanol terephthalate)-b-poly (ethylene glycol)], PHBV (Poly3-hydroxybutyrate-Poly3-hydroxyvalerate) and PEGT/PBT [Poly (butylene terephthalate)/poly (ethylene glycol) terephthalate], and to study their effects on canine smooth muscle cells(SMCs) growth after surface modification. Methods: The contact angles were measured to compare the hydrophilicity of T20, PHBV, and PEGT/PBT scaffolds. Then SMCs were cultivated on these biodegradable scaffolds; their proliferation and growth were assayed by MTT assay, FITC and electron microscopic observation for evaluation of their in vitro biocompatibility. The growth of SMCs was also assayed on the 3 scaffolds after they were pretreated with gelatin or Poly-1-lysine. Results: The contact angles of 3 scaffolds were all less than 90°(PEGT/PBT>T20>PHBV). MTT assay showed that SMCs adhered to and grew well on T20, PHBV, and PEGT/PBT scaffolds. The cell viability began to increase 24 h after cultivation (PEGT/PBT>T20>PHBV, PPEGT/PBT>PHBV, P<0.01). FITC observation showed that SMCs grew well and electron microscopic observation showed a confluent growth of SMCs with abundant extracellular matrix. The viability of SMCs was significantly higher on scaffolds pretreated with gelatin or Poly-1-lysine than on those without pretreatment(P<0.01). Conclusion: T20, PHBV, PEGT/PBT have good in vitro biocompatibility; the scaffolds made of these materials can obviously improve cell attachment after surface modification.