Efficacy comparison of intravitreal injection of Conbercept versus Aflibercept in the treatment of pachychoroid neovasculopathy / 国际眼科杂志(Guoji Yanke Zazhi)

AIM:To observe and compare the clinical efficacy and safety of intravitreal injection of conbercept or aflibercept in the treatment of pachychoroid neovasculopathy(PNV).METHODS:Retrospective case-control study. A total of 33 patients(35 eyes)diagnosed as PNV in our hospital from February 2018 to October 2022 were divided into 14 cases(14 eyes)in conbercept group and 19 cases(21 eyes)in aflibercept group according to the treatment methods. The best corrected visual acuity(BCVA), subfoveal choroidal thickness(SFCT)and central macular thickness(CMT), injection times and clinical complications of the two groups were compared before and 1, 3 and 6mo after treatment.RESULTS:BCVA, CMT and SFCT in both groups were significantly improved after 1, 3 and 6mo of treatment(all P<0.05). During the whole follow-up period, the number of intravitreal injections in the two groups were 2(2, 3)and 2(1.5, 2)respectively, and there was no significant difference(P=0.423). No serious complications occurred during the treatment of the two groups.CONCLUSION:Both intravitreal injections of conbercept and aflibercept can treat PNV with similar therapeutic effects. The desired clinical outcome is achieved by improving the anatomy while improving visual acuity.

Effects of ribosomal protein L41 (RPL41) on the proliferation and apoptosis of human retinoblastoma Y79 cells and its mechanisms / 眼科新进展

Objective To study the effects of ribosomal protein L41 (RPL41) on the proliferation and apoptosis of human retinoblastoma Y79 cells and its underlying mechanisms.Methods Y79 cells were seeded in RPMI 1640 medium containing 10％ fetal bovine serum for passage culture.Then the cells were divided into control group,with cells left untreatment,(40 μmol · L-1,80 μmol · L 1 and 120 μmol · L-1) RPL41 treatment group according to the concentration.Next CellTiter-Glo fluorescence cell viability testing system was used to observe the viability of Y79 cells in all groups,and flow cytometry was applied to measure the cell apoptotic rate in 100 μmol · L 1 RPL41 treatment group,with Hoechst staining for the observation of nuclear morphometry of apoptotic cells,and finally,Western blot was used to determine the expression of activating transcription factor 4 (ATF4) of each group.Results Compared with the control group,the viability of Y79 cells in the 40 μmol · L-1 RPL41 treatment group was (97.9 ± 1.5) ％,with no significant difference (P =0.055);and the viability in the 80 μmol · L-1 and 120 μmol · L-1 RPL41 treatment group was (87.6 ± 1.8)％ and (63.9 ± 2.0) ％,respectively,both of which were significantly different from the control group (both P ＜ 0.05),so RPL41 inhibited the viability of Y79 cells,and 100 μmol · L-1 RPL41 promoted the apoptosis of Y79 cells,with the apoptotic rate of (17.33 ± 2.47)％.Compared with normal cells,the apoptotic cells in the 100 μmol · L 1 RPL41 treatment group showed bright color and smaller cell volume by Hoechst staining.Western blot showed that PRL41 significantly decreased the expression of ATF4 protein and the expression of ATF4 protein in the 40 μmol · L 1,80 μmol · L-1 and 120 μmol · L 1 treatment group were 0.76 ± 0.04,0.29 ± 0.04,0.29 ± 0.05,respectively,all of which were significantly different from the control group (all P ＜ 0.01).Conclusion RPL41 can inhibit the proliferation and promote the apoptosis of human retinoblastoma Y79 cell,and its mechanism may be related to the expression of ATF4.

Correlation between serum homocysteine level and retinal ganglion cell layer thickness in diabetic patients / 眼科新进展

Objective To explore the correlation between the level of serum homocysteine (Hcy) and the thickness of retinal ganglion cell layer (GCL) on optical coherence tomography (OCT) in patients with type 2 diabetes.Methods Totally 60 diabetic patients were collected from October 2016 to October 2017 in the Shengjing Hospital of China Medical University,and they were divided into two groups:diabetic patients without retinopathy (NDR group,n =30) and non-proliferative diabetic retinopathy group (NPDR group,n =30) according to the ETDRS classification,and meanwhile additional 30 healthy subjects were enrolled as control group.The level of serum Hcy was detected,and the retinal GCL thickness was measure using OCT in all patients for the analysis of the correlation of serum Hcy level with the thickness of GCL.Results The serum Hcy level was (11.87 ± 2.19) nmol · L-1 in the control group,(14.87 ± 0.42)nmol · L-1 in the NDR group and (20.77 ± 2.40) nmol · L-1 in the NPDR group,which was significantly increased gradually,and the difference was statistically significant (P =0.000),but the thickness of GCL was (88.33 ± 6.36) μm,(81.73 ± 1.41) μm and (64.00 ± 12.73) μm in the three groups,accordingly,which was decreased significantly gradually,with statistically significant difference (P =0.000).Along with the progress of fundus lesions,the level of serum Hcy increased,but the thickness of GCL decreased,and there was a significant negative correlation of the serum Hcy level with the thickness of GCL in the retina by Pearson (r =-0.908,P =0.000).Conclusion The increase of serum Hcy level in diabetic patients is associated with the decrease of retinal GCL thickness,and Hcy is involved in neurodegenerative changes in patients with diabetic retinopathy.

Comparisons of Emu Necrotic Femoral Head Micro Structure Repaired in Two Different Methods / 中国医学科学院学报

<p><b>OBJECTIVE</b>To compare emu necrotic femoral head micro structure repaired in two different methods.</p><p><b>METHODS</b>Fifteen adult emus were divided into 3 groups (all n=5), and the right femoral head was selected to research. The first group was the control group; in the second group, femoral head necrosis was made by cryogen with liquid nitrogen; and in the third group, femoral head necrosis was made by local pure ethanol injection. Right femurs were taken for micro CT examination,then femoral head micro structures were compared among these three groups.</p><p><b>RESULTS</b>No infection or unexpected death was found in all groups. Compared with normal group, necrotic femoral heads in cryogen group showed that bone mineral density significantly reduced after repaire (P=0.015), trabecular space significantly reduced (P=0.001), bone volume fraction significantly enlarged (P=0.036), bone surface/volume fraction (P=0.032) and trabecular numbers (P=0.002) significantly enlarged; trabecular thickness showed no significant difference (P=0.060). Compared with control group, necrotic femoral heads in ethanol group showed that bone mineral density significantly enlarged after repaire (P=0.001), trabecular thickness (P=0.003) and bone surface/volume fraction (P=0.022) significantly enlarged, trabecular space (P=0.001) and bone volume fraction (P=0.001) significantly reduced; the trabecular numbers showed no significant difference (P=0.143). Compared with ethanol group, necrotic femoral heads in cryogen group showed significant lower bone mineral density after repair (P=0.001), significantly lower bone volume fraction (P=0.001), significantly lower trabecular thickness (P=0.001), significantly higher bone surface/volume fraction (P=0.022) and higher trabecular numbers (P=0.003); the trabecular space showed no significant difference (P=0.398).</p><p><b>CONCLUSION</b>Different repair methods make reconstructed femoral head weight bearing area have different bone structure and bone mineral density, along with different bone trabecular quality.</p>

Study of animal model of osteonecrosis induced by local ethanol injection in emu / 中国医学科学院学报

<p><b>OBJECTIVE</b>To establish a new animal model of osteonecrosis of the femoral head by local ethanol injection in emu.</p><p><b>METHODS</b>Eight milliliter ethanol was injected slowly to the operated femoral head with customized probe in twenty adult male emus. Postoperatively, hip magnetic resonance imaging was performed at 1, 4, 8, 12 weeks. After emus were sacrificed, the femurs were collected for micro-computed tomography and histological analysis.</p><p><b>RESULTS</b>No emu demonstrated signs of infection or died unexpectedly. Magnetic resonance imaging examination showed broad edema at proximal femur at 1(th) week, and the edema decreased with time, till local edema at femoral head at the 12(th) week. Histological images showed human-like osteonecrotic changes with active bone repair. There were significant differences in trabecular structure and bone mineral density between the operated and intact femoral heads. No collapse was found 6 months after the operation.</p><p><b>CONCLUSIONS</b>This emu model of femoral head osteonecrosis by local ethanol injection can progress to early stage osteonecrosis. The different repair methods may have certain correlation with the results of osteonecrosis of the femoral heads.</p>

Reconstruction of the medial patellofemoral ligament using hamstring tendon graft with different methods: a biomechanical study / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To measure the tensile strength of the normal medial patellofemoral ligament (MPFL), and evaluate the biomechanics of different fixation methods of the hamstring tendon graft on the patella.</p><p><b>METHODS</b>Eight fresh cadaver knees were prepared by isolating the patella, leaving only the MPFL as its attachment to the medial condyle of femur. The MPFL was reconstructed by three different methods: four-suture fixation, anchors-single suture fixation, and anchors-double suture fixation. The tensile strength and the elongation of the normal MPFL and the tendon grafts were measured.</p><p><b>RESULTS</b>The tensile strength of the four-suture fixation group (234.86±49.02 N) was stronger than that of the normal MPFL (146.91±25.30 N, P=0.0014) and the anchors-single suture group (159.17±49.07 N, P=0.0077), while weaker than that of the anchors-double suture group (314.74±78.46 N, P=0.0052) CONCLUSIONS: With regard to the tensile strength, the four-suture fixation method is reliable for clinical use. Compared with the anchor-suture method, the four-suture fixation method which has no specific implants is more economical, convenient and efficient.</p>

Combined effects of NEL-like type 1 gene and zoledronate in preventing collapse of the femoral head / 中国医学科学院学报

<p><b>OBJECTIVE</b>To determine if combined therapy consisting of NEL-like type 1 gene (NELL-1) and zoledronate can prevent the collapse of the femoral head and stimulate the new bone formation in an animal model of osteonecrosis.</p><p><b>METHODS</b>Ischemic osteonecrosis was surgically induced in 24 SD rats, whicih were equally randomly divided into three groups: combination group, treated with both NELL-1 and zoledronate; sham operation group; and placebo group, treated with normal saline solution. The animals were killed 5 weeks after surgery. Radiography, MicroCT, histology, and immunohistochemistry were performed to analyze the results.</p><p><b>RESULTS</b>Morphologically, the femoral head was at good shape in the combination group, while mildly flattened femoral head was seen in the placebo group. No heterotopic ossifications were observed in each group. MicroCT assessment showed significantly higher total and bone mineral volume in the combination group than in the placebo group (P<0.01), whereas no such significant difference was found when compared with the sham operation group(P>0.05). Histological assessment showed more active osteoblast activity and reduced osteoclast activity in the combination group compared with placebo group.</p><p><b>CONCLUSION</b>A combination of NELL-1 and zoledronate can decrease the femoral head deformity while stimulating bone formation in a traumatic rat osteonecrois model, showing a potential to reverse the osteonecrosis.</p>

In vitro cartilage production using an extracellular matrix-derived scaffold and bone marrow-derived mesenchymal stem cells / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Cartilage repair is a challenging research area because of the limited healing capacity of adult articular cartilage. We had previously developed a natural, human cartilage extracellular matrix (ECM)-derived scaffold for in vivo cartilage tissue engineering in nude mice. However, before these scaffolds can be used in clinical applications in vivo, the in vitro effects should be further explored.</p><p><b>METHODS</b>We produced cartilage in vitro using a natural cartilage ECM-derived scaffold. The scaffolds were fabricated by combining a decellularization procedure with a freeze-drying technique and were characterized by scanning electron microscopy (SEM), micro-computed tomography (micro-CT), histological staining, cytotoxicity assay, biochemical and biomechanical analysis. After being chondrogenically induced, the induction results of BMSCs were analyzed by histology and Immunohisto-chemistry. The attachment and viability assessment of the cells on scaffolds were analyzed using SEM and LIVE/DEAD staining. Cell-scaffold constructs cultured in vitro for 1 week and 3 weeks were analyzed using histological and immunohistochemical methods.</p><p><b>RESULTS</b>SEM and micro-CT revealed a 3-D interconnected porous structure. The majority of the cartilage ECM was found in the scaffold following the removal of cellular debris, and stained positive for safranin O and collagen II. Viability staining indicated no cytotoxic effects of the scaffold. Biochemical analysis showed that collagen content was (708.2-44.7) µg/mg, with GAG (254.7 ± 25.9) µg/mg. Mechanical testing showed the compression moduli (E) were (1.226 ± 0.288) and (0.052 ± 0.007) MPa in dry and wet conditions, respectively. Isolated canine bone marrow-derived stem cells (BMSCs) were induced down a chondrogenic pathway, labeled with PKH26, and seeded onto the scaffold. Immunofluorescent staining of the cell-scaffold constructs indicated that chondrocyte-like cells were derived from seeded BMSCs and excreted ECM. The cell-scaffold constructs contained pink, smooth and translucent cartilage-like tissue after 3 weeks of culture. We observed evenly distributed cartilage ECM proteoglycans and collagen type II around seeded BMSCs on the surface and inside the pores throughout the scaffold.</p><p><b>CONCLUSION</b>This study suggests that a cartilage ECM scaffold holds much promise for in vitro cartilage tissue engineering.</p>

Three-dimensional deformation field measurement system based on micro-CT images / 医用生物力学

Objective To develop a novel measurement system composed of micro-CT, mechanical loading device and digital volume correlation (DVC) technique, so as to measure the three-dimensional microstructural deformation field in bone tissue. Methods Uniaxial compression was applied on the specimen with the micromechanical loading device, and CT scans were also conducted while maintaining the same loads; then sequential CT images were matched and searched accordingly by DVC method to calculate the micro-displacement in the specimen along three directions before and after loading; repeated scanning of zero-displacement and rigid body translation were used to evaluate the accuracy and precision of the system. The three-dimensional distribution of displacement field in bovine cancellous bone was measured by the system. Results The result from repeated scanning of zero-displacement showed that the highest accuracy of measurement was performed in the loading direction and the precision was less than tenth of the CT resolution. The result of rigid body translation showed that the standard deviation was 0.001~0.002 μm. For cancellous bone specimen under the load of 600 N, the range of micro-displacement was 100.35~110.25 μm, with multilayer field distribution. Conclusions The accuracy and precision of this measurement system can meet the requirement of DVC method. It is proved that this system can be used for measuring the three-dimensional micro-deformation field in the cancellous bone and as a measurement platform for investigating the relationship between deformation distribution and structural response in bone tissue for the future research.

Effect and mechanism of zoledronate on prevention of collapse in osteonecrosis of the femoral head / 中国医学科学院学报

<p><b>OBJECTIVE</b>To observe the effect and mechanism of zoledronate on prevention of collapse in an animal model of osteonecrosis.</p><p><b>METHODS</b>Ischemic osteonecrosis was surgically induced in 16 SD rats (which were further divided into zoledronate group and placebo group); another 8 rats were used as sham surgery group (n=8). The animals were killed 5 weeks after surgery. Radiographic, Micro-CT, histological, and immunohistochemical assessments were performed.</p><p><b>RESULTS</b>Radiographic assessment showed better preservation of the femoral head shape in the zoledronate group than in the placebo group but not significantly different from the sham surgery group. Micro-CT assessment showed higher total volume, bone volume, and total mineralized content in the zoledronate group(all P0.05). Compared with the placebo group, the zoledronate group had reduced osteoclast and osteoblast activity, as confirmed by histological examinations.</p><p><b>CONCLUSION</b>Zoledronate can decrease the femoral head deformity by reducing the osteoclast activity while suppressing new bone and vessels formation in a rat model of traumatic osteonecrosis, and therefore may delay the collapse of femoral head.</p>

Evaluation of an extracellular matrix-derived acellular biphasic scaffold/cell construct in the repair of a large articular high-load-bearing osteochondral defect in a canine model / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Osteochondral lesion repair is a challenging area of orthopedic surgery. Here we aimed to develop an extracellular matrix-derived, integrated, biphasic scaffold and to investigate the regeneration potential of the scaffold loaded with chondrogenically-induced bone marrow-derived mesenchymal stem cells (BMSCs) in the repair of a large, high-load-bearing, osteochondral defect in a canine model.</p><p><b>METHODS</b>The biphasic scaffolds were fabricated by combining a decellularization procedure with a freeze-drying technique and characterized by scanning electron microscopy (SEM) and micro-computed tomography (micro-CT). Osteochondral constructs were fabricated in vitro using chondrogenically-induced BMSCs and a biphasic scaffold, then assessed by SEM for cell attachment. Osteochondral defects (4.2 mm (diameter) × 6 mm (depth)) were created in canine femoral condyles and treated with a construct of the biphasic scaffold/chondrogenically-induced BMSCs or with a cell-free scaffold (control group). The repaired defects were evaluated for gross morphology and by histological, biochemical, biomechanical and micro-CT analyses at 3 and 6 months post-implantation.</p><p><b>RESULTS</b>The osteochondral defects of the experimental group showed better repair than those of the control group. Statistical analysis demonstrated that the macroscopic and histologic grading scores of the experimental group were always higher than those of the control group, and that the scores for the experimental group at 6 months were significantly higher than those at 3 months. The cartilage stiffness in the experimental group (6 months) was (6.95 ± 0.79) N/mm, 70.77% of normal cartilage; osteochondral bone stiffness in the experimental group was (158.16± 24.30) N/mm, 74.95% of normal tissue; glycosaminoglycan content of tissue-engineered neocartilage was (218 ± 21.6) µg/mg (dry weight), 84.82% of native cartilage. Micro-CT analysis of the subchondral bone showed mature trabecular bone regularly formed at 3 and 6 months, with no significant difference between the experimental and control groups.</p><p><b>CONCLUSION</b>The extracellular matrix-derived, integrated, biphasic scaffold shows potential for the repair of large, high-load-bearing osteochondral defects.</p>

A new animal model of osteonecrosis induced by focal alternative cooling and heating insults / 中国医学科学院学报

<p><b>OBJECTIVE</b>To establish a new animal model of osteonecrosis of the femoral head(ONFH) with improved consistency and incidence of femoral head collapse for studies on the mechanism of osteonecrosis. and on the assessment of treatment effectiveness.</p><p><b>METHODS</b>Twenty adult male emus were used. Guide instrumentation was constructed to position the customized probe just articularly and at the proximal part of the femoral head. An alternating focal liquid nitrogen freezing and radiofrequency heating was applied. At 2, 4, 8, 12 and 16 weeks after surgery, hip magnetic resonance imaging (MRI) was performed. Before the emus were sacrificed, barium sulfate was infused to lower extremities for microangiography. The femoral samples were scanned by micro-computed tomography (Micro-CT) and evaluated histologically.</p><p><b>RESULTS</b>No bird demonstrated signs of infection or died unexpectedly. Hip MRI showed changes massive edema at the 4th week, increasingly localized abnormal signals at the 8th'" week, and femoral head collapse at the 12'h week. Micro-CT scans and histological images at the 16th week showed human-like osteonecrotic changes with impaired local blood supply. Bone mineral density of the collapsed head was (380. 31 + 28. 12) mg/cm3 and trabecular spaces were (0. 86 ±0.32) mm; both were significantly lower than those in the control side, which were (415.75 41.28) mg/cm3 and (1. 17 ± 0. 17) mm, respectively (P < 0. 05). Bone volume fraction of the collapsed head was(47.28 ± 17. 14)% and trabecular thickness was (506. 17 ± 220. 58) p.m; both were significantly higher than those at control side, which were (30. 92 ± 4. 01)% and (325. 50 ±44. 53) pm, respectively (P <0. 05). The microangiography at the 16th week showed that vessel volume fraction was (0. 315 ± 0. 055)% , which was significantly higher than the collapsed side [ (0. 142 ± 0. 059)% ] (P <0. 05).</p><p><b>CONCLUSIONS</b>The emu model of fem-oral head osteonecrosis was successfully established using focal alternating cooling and heating insults. The models, with improved consistency and incidence of femoral head collapse, can be used in studies on the mechanism of osteonecrosis and on the assessment of treatment effectiveness.</p>

Effect of the dipeptide Arg-Gln on retinopathy of prematurity in mice / 国际眼科杂志(Guoji Yanke Zazhi)

·AIM: To investigate the effect of the dipeptide Arg-Glnon retinal neovascularization of retinopathy of prematurity(ROP) in the oxygen-induced retinopathy (OIR) animalmodel.·METHODS.- Forty-eight 7-day-old C57BL/6J mice were exposed to 750mL/L oxygen for 5 days and then to normal situation to produce the murine model of oxygen-induced retinopathy (OIR). All mice received twice daily intra- peritoneal injections of PBS or the dipeptide Arg-Gln(1.0, 3.0, 5.0g/kg per day), starting on postnatal day 12 and continuing till postnatal day 17. Experimental groups (36 mice, 12 in each group) received Arg-Gln, while the control group (12 mice) received PBS. All mice were executed at postnatal day 17. The changes of retinal vessels of mice were observed by ADPase histochemical technique and HE staining was used to count preretinal neovascular nuclei. RNA was isolated from retinas of 28 mice (7 in each group) selected at random and VEGF mRNA level of each group was measured by real-time RT-PCR.·RESULTS; Neovascularization reduced in retinas of the dipeptide Arg-Gln treated group in a dose-dependent manner. Compared with control group, experimental group had diminished non-perfusion area and neovascular tufts in retinal flatmount. The number of the endo-theliocyte nuclei of new vessels extending from retina to vitreous was significantly less in the eyes of the experimental group than in control group. Arg-Gln at 5g/kg per day reduced preretinal neovascularization by about 75% (P＜ 0.01). There was a significant reduction in VEGF mRNA at the 17th day in Arg-Gln treated group compared with control group(P＜0.01).·CONCLUSION; Arg-Gln dramatically inhibits retinal angiogenesis in OIR and this effect is associated with a reduction in retinal VEGF mRNA level. It appears to be a safe way to prevent and treat some neovascular retinal diseases including retinopathy of prematurity.

Inhibition of retinal angiogenesis by PEDF / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To investigate the effect of PEDF on retinal neovascularization in mice. METHODS: 40 7-day-old C57BL/6J mice was exposed to 750mL/L oxygen for 5 days and then to normal situation to produce the murine model of oxygen-induced retinopathy(OIR). One eye of the mouse was regarded as experimental one and the other served as control. Eyes in experimental group received intravitreal injection of PEDF and eyes in control group received intravitreal injection of PBS at postnatal day 12. All mice were executed at postnatal day 17. The changes of retinal vessels of mice were observed by ADPase histochemical technique. The inhibitory effect of PEDF on retinal neovascularization was evaluated by counting the endotheliocyte nuclei of new vessels which extended from retina to vitreous in the tissue slice of HE staining. RESULTS: Neovascularization was reduced, retinal blood vessels distributed regularly and non-perfusion areas were not found in eyes of experimental group compared with control group. The number of endotheliocyte nuclei of new vessels extending from retina to vitreous was significantly less in the eyes of experimental group (10.18±1.74) than that in control group (38.89±2.98) (P<0.01). Retinal toxicity and inflammatory reactions were not found in tissue slice.CONCLUSION: PEDF inhibits retinal angiogenesis in OIR and the feasibility should be determined for use of PEDF in ocular angiogenesis treatment.

Research of the peak force of pullout about different thoracic hemi-epiphyseal compression staples in animal / 中华外科杂志

<p><b>OBJECTIVE</b>To evaluate the initial dislocation resistance of the pullout force of different material or different type of goats thoracic hemi-epiphyseal compression staples.</p><p><b>METHODS</b>According to the measuring anatomic data of thoracic vertebra (T6 approximately T11) specimens in goats (age 2 approximately 3 months), we designed stainless steel staple whose original distances between two opened prone were 10 mm and three kinds of shape memory alloy (SMA) staples whose original distances between two opened prone were respectively 5.0, 6.5 and 8.0 mm. Four specimens were used and each was cut into three functional spinal units (FSU) of T6 - T7, T8 - T9 and T10 - T11, then FSU were redistributed. Stainless steel staples and SMA staples were implanted into both sides of FSU. There were four groups: group I was stainless steel staples. group II was SMA of 5.0 mm. group III was SMA of 6.5 mm. group IV was SMA of 8.0 mm. The peak force of pullout in each FSU was measured on 858 biomechanical test machine.</p><p><b>RESULTS</b>The peak force of group I was (20.62 +/- 9.15) N, group II was (74.18 +/- 8.81) N, group III was (51.28 +/- 5.44) N, group IV was (39.13 +/- 7.54) N. It is found that there were statistically different between all groups (P < 0.05). The peak force values of group I were lowest than others.</p><p><b>CONCLUSIONS</b>Differences of the initial dislocation resistance in different materials. SMA staples exhibit higher pullout force. Meanwhile, the pullout forces were also different between SMA staples, the smaller original distance the higher peak force of pullout.</p>

The clinical application and biomechanical study of reconstruction of anterior and posterior cruciate ligament with hamstring tendons knot implant fixation / 中华外科杂志

<p><b>OBJECTIVE</b>To investigate the feasibility of reconstruction of anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) with hamstring tendons knot implant fixation.</p><p><b>METHODS</b>Fifty-two cases of ACL and PCL old injury were reconstructed under the arthroscopy with double bundles hamstring tendons knot implant fixated in the bottle-necked femoral tunnel. The tibia side were fixated by tendon weave suture cross tied a knot at the bone bridge of tibia. In this group reconstruction of ACL was in 25, PCL and ACL at the same time reconstruction in 15, PCL in 12. The failure test and displacement evaluation were used to study the biomechanics of reconstruction of ACL by hamstring tendon knot implant fixation (n = 13) in porcine knees. The control group were reconstructed with bone-patellar tendon-bone B-PT-B and interference screw (n = 11). The tibia side tendon weave suture immobility by cross tied a knot at the tibia bone bridge (n = 7) and interference screw in the tibia tunnel (n = 8).</p><p><b>RESULTS</b>Forty-nine cases were followed up, average 14.6 months. The results of Lanchman test was negative in 46 cases, positive in 3 cases. Preoperative Lysholm score was 56.7, and postoperative was 92.8. According to the knee joint effective evaluate standard, 46 were excellent and 3 good. The maximal pull-out force of hamstring tendons knot implanted fixation had been greater than B-PT-B fixation by interference screw. There were similar displacement in 100 N and 400 N load between hamstring tendons knot implant fixation and B-PT-B (P > 0.05). Peak force test maximal displacement evaluation and failure energy absorption measurement showed that hamstring tendons knot implant fixation was significantly greater than B-PT-B (P < 0.01). The failure test and displacement evaluation of tendon fixation by weave suture knot at the tibia bone bridge cross tie were greater than B-PT-B fixation by interference screw.</p><p><b>CONCLUSION</b>The methods of reconstruct of ACL and PCL by hamstring tendons knot implant fixation are feasible. The advantages include: it is biological fixation, not machine fixation; it may benefit for tendons with bone tunnel healing and decrease medical cost. Decreasing or eliminating displacement is helpful to prevent relaxation after reconstruction of ACL and PCL.</p>

Experimental study on preparation of decellularized artery vascular graft matrix and explantation of carotid artery allografts / 中华外科杂志

<p><b>OBJECTIVE</b>To set up a new process to access the preparation of decellularized artery grafts. And to evaluate the feasibility of decellularized artery allografts was evaluated.</p><p><b>METHODS</b>This study compared the effects of four extraction chemicals [1% t-octyl-phenoxypolyethoxyethanol (Triton X-100), 1% tri (n-butyl) phosphate (TnBP), and 1% sodium dodecyl sulfate (SDS) and trypsin (0.125, 0.25%) on thoracic artery vascular for 24 h (except trypsin for 2 h). At the base of it, a four-step process, including hypotonic, hypertonic solutions and combining with 1% Triton X-100 and 1% SDS detergents, were performed in rabbit thoracic artery vascular. Histological examination, tensile tests and expanding-burst tests were done on the samples. The decellularized carotid artery allografts were transplanted in other rabbits.</p><p><b>RESULTS</b>Treatment with 1% SDS or 1% Triton X-100 for 24 h could remove most cells with retention of near normal structure. A four-step process could remove all cells with the extracellular matrix well conserved. The pulling mechanical properties and burst pressure of decellularized carotid artery were similar to the control. The decellularized carotid artery allografts (diameter of 2 mm) were patent at explanting up to 2 months.</p><p><b>CONCLUSIONS</b>The acellular artery vascular graft matrix is well prepared with four-step process including detergents, such as TritonX-100, SDS without compromising the graft structure or mechanical properties significantly. The carotid artery allografts (diameter of 2 mm) decellularized by the process are patent at explanting up to 2 months.</p>

The preparation, structure evaluation and preliminary application of biomimetic biphasic calcium phosphate scaffold / 中华外科杂志

<p><b>OBJECTIVE</b>To fabricate biomimetic biphasic calcium phosphate BCP ceramic scaffolds using three-dimensional (3D) gel-lamination technology and evaluated their structure with 3D parameters and related method.</p><p><b>METHODS</b>Series two-dimensional images of femoral head's specimen of dogs were obtained by micro-computed tomography (Micro-CT). According to these images, porous biomimetic biphasic calcium phosphate (BCP) ceramic scaffolds with oriented trabecular structure were fabricated by three-dimensional (3D) gel-lamination technology. And then, the three-dimensional structure of the scaffolds were reconstructed by computer according to Micro-CT images of these scaffolds and evaluated by three-dimensional parameters. These parameters included bone volume fraction (BVF, BV/TV), bone surface/bone volume (BS/BV) ratio, trabecular thickness (Tb.Th), trabecular number (Tb.N), trabecular spacing (Tb.Sp) and structure model index (SMI). The biomechanical properties and biocompatibility of these scaffolds were also evaluated in the study. Six scaffolds, which were combined with BMCs (bone mesenchymal cells, BMCs), were planted into the bone defect of six dogs' femoral head respectively.</p><p><b>RESULTS</b>There was no significant difference between trabecular samples and BCP scaffolds in BV/TV, Tb.Th, Tb.N, and Tb.Pf (P > 0.05). The trabecular system of the scaffold, which had some orientation, represented plate-like model. With a micro-porous porosity of 62%, the average compressive modulus and ultimate strength along the axis of the scaffolds reached (464.0 +/- 36.0) MPa and (5.6 +/- 0.8) MPa respectively. The results of animal test indicated that the trabeculae of these scaffolds were covered by a layer of new bone after 10 weeks of operation.</p><p><b>CONCLUSION</b>Porous BCP scaffolds have been produced with oriented microarchitectural features designed to facilitate vascular invasion and cellular attachment and with initial mechanical properties comparable to those of trabecular bone.</p>

Experimental Study of Adenovirus Carrying Pigment Epithetium-Derived Factor Gene Treatment on Retino-pathy of Prematurity / 实用儿科临床杂志

Objective To explore the effect of adenovirus carrying pigment epithelium-derived factor(ADV-PEDF)gene treatment on retinal neovascularization of mice with retinopathy of prematurity (ROP).Methods Sixty 7 d C57BL/6J mice were put into the environment with (750?5)mL/L oxygen for 5 days and returned to normal environment to establish animal models of ROP.The eyes in experimental group received an intravitreal injection of 1 ?L of ADV-PEDF,and the same volume of ADV-LacZ was injected into the eyes of mice in control group.The ADPase histochemical staining was used for retinal flatmount to observe changes of retinal vessels.The inhibitory effects of PEDF on retinal neovascularization were evaluated by counting the endotheliocyte nuclei of new vessels extending from retina to vitreous in the tissue-slice.The expression of PEDF in retina were detected by Western blotting.Results The vessels from optic disc were very thin and distorted in eyes of control group in retinal flatmount.There were avascular area around optic disc and neovascular trufts beside avascular area.Compared with control group,regular distributions and no conspicuous avascular area were found in eyes of experiment group in retinal flatmount.The number of the endotheliocyte nuclei of new vessels extending from retina to vitreous was less in the eyes of the experiment group than that in control group (P