近视性屈光参差患者双眼角膜生物力学及眼压特点的研究

目的观察近视性屈光参差患者双眼角膜生物力学及眼压的特点。设计回顾性病例系列。研究对象116例(232眼)近视性屈光参差患者。方法按每人双眼等效球镜度(SE)高低分为低SE眼和高SE眼,比较双眼标志角膜生物力学参数的角膜阻力因子量(CRF)、角膜滞后量(CH)和眼压的特点;根据双眼间等效球镜度差值分为组1(SE差值2.5～3.0 D,37例)、组2(SE差值﹥3.0 D～6.0 D,44例)和组3(SE差值>6.0 D,35例),比较不同屈光参差程度组内低SE眼和高SE眼CRF、CH和眼压的特点。主要指标CRF、CH、角膜补偿眼压。结果总体低SE眼和高SE眼间的CRF分别为(10.40±1.74)mm Hg和(10.38±1.63)mmHg,差异无统计学意义(t=0.113,P=0.683),CH分别为(9.71±1.68)mm Hg和(9.66±1.90)mm Hg,差异亦无统计学意义(t=0.144,P=0.886)。在屈光参差程度不同的三组中,双眼间低SE眼与高SE眼CRF的差异均无统计学意义,组1:(10.58±1.74)mm Hg,(10.65±1.61)mm Hg(t=-0.175,P=0.862);组2:(10.31±1.88)mm Hg,(10.14±1.58)mm Hg(t=0.434,P=0.666);组3:(10.35±1.47)mm Hg,(10.31±1.65)mm Hg(t=-0.141,P=0.903)。各组双眼间CH差异亦均无统计学意义,组1:(9.66±1.59)mm Hg,(9.74±1.52)mm Hg(t=-0.210,P=0.834);组2:(9.89±1.90)mm Hg,(9.83±2.21)mm Hg(t=0.122,P=0.903);组3:(9.59±1.35)mm Hg,(9.35±1.71)mm Hg(t=0.336,P=0.512)。总体低SE眼和高SE眼间的角膜补偿眼压分别为(18.37±3.58)mm Hg和(18.67±3.48)mm Hg,也未发现差异有统计学意义(t=-0.607,P=0.545)。结论近视性屈光参差患者双眼间角膜生物力学参数及眼压无显著性差异。     

圆锥角膜患者双眼角膜生物力学性能的对称性

目的：应用超高频Scheimpflug角膜生物力学分析仪（CorVis-ST）评估双眼圆锥角膜患者角膜生物力学性能的对称性。方法：病例系列研究。于2013 年12 月至2015 年7 月间根据Amsler-Krumeich圆锥角膜分期标准诊断纳入温州医科大学附属眼视光医院视光门诊就诊的双眼圆锥角膜患者40 例（80 眼）。每只受试眼均使用CorVis-ST测量3 次,得到10 项生物力学参数及眼内压（IOP）、中央角膜厚度（CCT）等12项参数。双眼间差异分析采用Student's t检验和Mann-Whitney U检验,双眼一致性分 析采用Bland-Altman方法。结果：12个CorVis-ST参数的双眼95%一致性界限分别为：第1次压平时间（AP1 T） -0.56 ~ 0.61 ms（Z=0.441,P =0.229）,第1次压平长度-0.75 ~ 0.77 mm（t =-0.178,P =0.907）,第1次压平速度-0.063 ~ 0.053 m/s（Z=-1.528,P =0.171）,第2次压平时间（AP2 T）-1.01 ~ 0.84 ms（t =-0.848, P =0.269）,第2 次压平长度-0.96 ~ 1.02 mm（t =-0.342,P =0.715）,第2 次压平速度-0.22 ~ 0.22 m/s（t =-0.087,P =0.812）,最大形变时间（T）-1.38 ~ 1.11 ms （Z =-1.170,P =0.162）,最大形变峰间距-1.70 ~ 3.93 mm（Z =-3.321,P =0.001）,最大形变曲率-2.30 ~ 2.74 mm（t =1.014,P =0.287）,最大形变幅度-0.34 ~ 0.28 mm（t =-1.057,P =0.221）,眼内压-3.61 ~ 3.91 mmHg（t =-1.152,P =0.267）,CCT-136 ~ 152 μm（t =-0.698,P =0.323）,双眼间差异除最大形变峰间距外均无统计学意义。对应的一致性比值分别为8.8%、45.0%、37.0%、4.6%、65.8%、50.0%、8.5%、78.8%、46.5%、29.1%、32.6%、32.3%。在12 个参数值中,AP1 T、AP2 T、T一致性比值较小,双眼间有着较高的一致性。结论：AP1 T、AP2 T、T拥有较高的双眼间对称性,在应用CorVis-ST对圆锥角膜患者行角膜生物力学性能研究时,应考虑到双眼间角膜生物力学对称性对结果的影响。     

Physical Training During Pregnancy and Lactation

Abstract

Plantar fasciitis is a painful condition affecting many athletes. Anatomic and biomechanical factors combined with overuse can contribute to its genesis. Correction of gait disturbances, changes in footwear, use of tension night splints, and stretching of tight calf and plantar tissues have all be proven to relieve symptoms. Anti-inflammatory modalities, including medications, iontophoresis, and corticosteroid injection generally provide temporary improvement. Recent studies on the efficacy of extracorporeal shock wave therapy are conflicting. Injections with platelet-rich plasma or sclerotic agents are currently under investigation for use in this and other similar conditions. A small percentage of patients with refractory symptoms may benefit from surgical release of the plantar fascia. Diagnosis and correction of biomechanical factors leading to this condition should be a mainstay of treatment and may prevent recurrences.     

Histomorphometric and removal torque analysis for TiO2-blasted titanium implants. An experimental study on dogs

The aim of the present study was to compare the anchorage of TiO2-blasted screw and cylindrical implants with conventionally used machine-produced screw and cylindrical implants inserted immediately in extraction sockets on dogs. 6 adult mongrel dogs had 3rd and 4th mandibular premolars extracted bilaterally and 24 commercial pure titanium implants were placed immediately in extraction sockets and covered with mucoperiosteum. Each dog had inserted 4 implants: 1 screw implant and 1 cylindrical implant blasted with titanium-dioxide-particles; 1 screw implant and 1 cylindrical implant with machine-produced (m.p.) surface (controls). After a healing period of 12 weeks, 16 implants from 4 animals were used for removal torque test, which demonstrated that significantly higher removal torque force was needed to unscrew the implants blasted with titanium-dioxide-particles, than the normal m.p. implants. The medians for the TiO2-blasted screw and cylindrical implants were > 150 Ncm and 105 Ncm, respectively, while the values for the m.p. implants were 60 Ncm and 35 Ncm, respectively. The SEM investigation demonstrated a high irregularity of the TiO2-blasted surface compared to the machined surface. The Ra and Rz values for surface roughness were higher for the TiO2-blasted implants than for the normal m.p. implants. Histomorphometrically, the arithmetic mean of the direct bone-implant contact fraction was 69%. There was no significant difference in direct bone-implant contact length fraction between TiO2-blasted implants and the control implants. The implants blasted with titanium-dioxide-particles in this study showed a better anchorage than implants with a machine-produced surface. The screw implants showed a better anchorage than the cylindrical implants.     

Early endosseous integration enhanced by dual acid etching of titanium: a torque removal study in the rabbit

Textured implant surfaces are thought to enhance endosseous integration. Torque removal forces have been used as a biomechanical measure of anchorage, or endosseous integration, in which the greater forces required to remove implants may be interpreted as an increase in the strength of bony integration. The purpose of this study was to compare the torque resistance to removal of screw-shaped titanium implants having a dual acid-etched surface (Osseotite) with implants having either a machined surface, or a titanium plasma spray surface that exhibited a significantly more complex surface topography. Three custom screw-shaped implant types - machined, dual acid-etched (DAE), and titanium plasma sprayed (TPS) - were used in this study. Each implant surface was characterized by scanning electron microscopy and optical profilometry. One DAE implant was placed into each distal femur of eighteen adult New Zealand White rabbits along with one of the other implant types. Thus, each rabbit received two DAE implants and one each of the machined, or TPS, implants. All implants measured 3.25 mm in diameter x 4.00 mm in length without holes, grooves or slots to resist rotation. Eighteen rabbits were used for reverse torque measurements. Groups of six rabbits were sacrificed following one, two and three month healing periods. Implants were removed by reverse torque rotation with a digital torque-measuring device. Three implants with the machined surface preparation failed to achieve endosseous integration. All other implants were anchored by bone. Mean torque values for machined, DAE and TPS implants at one, two and three months were 6.00+/-0.64 N-cm, 9.07+/-0.67 N-cm and 6.73+/-0.95 N-cm; 21.86+/-1.37 N-cm, 27.63+/-3.41 N-cm and 27.40+/-3.89 N-cm; and 27.48+/-1.61 N-cm, 44.28+/-4.53 N-cm and 59.23+/-3.88 N-cm, respectively. Clearly, at the earliest time point the stability of DAE implants was comparable to that of TPS implants, while that of the machined implants was an order of magnitude lower. The TPS implants increased resistance to reverse torque removal over the three-month period. The results of this study confirm our previous results that demonstrated enhanced bony anchorage to dual acid-etched implants as compared to machined implants. Furthermore, the present results indicate that dual acid etching of titanium enhances early endosseous integration to a level which is comparable to that achieved by the topographically more complex TPS surfaces.     

Local treatment of osteoporosis with alendronate-loaded calcium phosphate cement

Background A new treatment strategy is to target specific areas of the skeletal system that are prone to clinically significant osteoporotic fractures.We term this strategy as the ＂local treatment of osteoporosis＂.The study was performed to investigate the effect of alendronate-loaded calcium phosphate cement （CPC） as a novel drug delivery system for local treatment of osteoorosis.Methods An in vitro study was performed using CPC fabricated with different concentrations of alendronate （ALE,0,2,5,10 weight percent （wt％））.The microstructure,setting time,infrared spectrum,biomechanics,drug release,and biocompatibility of the composite were measured in order to detect changes when mixing CPC with ALE.An in vivo study was also performed using 30 Sprague-Dawley rats randomly divided into six groups：normal,Sham （ovariectomized （OVX） ＋ Sham）,CPC with 2％ ALE,5％ALE,and 10％ ALE groups.At 4 months after the implantation of the composite,animals were sacrificed and the caudal vertebrae （levels 4-7） were harvested for micro-CT examination and biomechanical testing.Results The setting time and strength of CPC was significantly faster and greater than the other groups.The ALE release was sustained over 21 days,and the composite showed good biocompatibility.In micro-CT analysis,compared with the Sham group,there was a significant increase with regard to volumetric bone mineral density （BMD） and trabecular number （Tb.N） in the treated groups （P ＜0.05）.Trabecular spacing （Tb.Sp） showed a significant increase in the Sham group compared to other groups （P ＜0.01）.However,trabecular thickness （Tb.Th） showed no significant difference among the groups.In biomechanical testing,the maximum compression strength and stiffness of trabecular bone in the Sham group were lower than those in the experimental groups.Conclusions The ALE-loaded CPC displayed satisfactory properties in vitro,which can reverse the OVX rat vertebral trabecular bone microarchitecture and biomechanical p     

Comparative biomechanical study of reversed less invasive stabilization system and proximal femoral nail antirotation for unstable intertrochanteric fractures

Objective Unstable intertrochanteric fractures （ITFs） are mostly treated by proximal femoral nail antirotation （PFNA）,Inter-Tan,Asian Hip,and other new internal fixation devices.But for complex unstable fractures,such as crushed lateral wall of the greater trochanter,the loss of fixation point on lateral wall slightly reduces the fixing effect.This study aimed to compare the biomechanical strengths between reversed less invasive stabilization system （LISS） and PFNA for treatment of unstable ITFs.Methods Forty synthetic femurs were used to simulate unstable ITFs in vitro and were fixed using the reversed LISS or PFNA.These fractures were divided into two groups depending on whether the lateral wall of the greater trochanter is intact or not （AO classification：31-A2.3 and 31-A3.3,respectively）.The load-displacement of femur,stiffness,ultimate load,and cyclic fatigue resistance were detected using an incremental load test and a dynamic fatigue test through an MTS 858 test system.Results For both 31-A2.3 and 31-A3.3,the vertical sinking displacement （VSD） of the femoral head under 500 N load was insignificantly smaller after treatment with reversed LISS than with PFNA,and when the displacement was 5 mm,the femoral head bore insignificantly greater load.The fixation with reversed LISS resulted in greater axial stiffness of the femur but smaller ultimate load.During the same cycle in the dynamic fatigue test,the VSD was insignificantly smaller with the fixation of reversed LISS.Conclusion Reversed LISS and PFNA have similar biomechanical strength for unstable ITFs.This conclusion should be supported by additional large-size research on basic biomechanics and clinical application.This is the first comparative biomechanical study comparing reversed LISS and PFNA for unstable ITFs.     

淫羊藿黄酮对去势大鼠骨生物力学性能的影响

目的：探讨淫羊藿黄酮对去势大鼠骨生物力学性能的影响。方法：选用2月龄雌性SD大鼠60只,随机分为6组,每组10只。A组：空白对照组,常规方法饲养,进行假手术处理;B组：去势组,不给予淫羊藿黄酮干预;C组：去势垣钙剂,每日灌服高效钙（75 mg·kg-1）垣维生素D3 21 IU·kg-1;D组：去势垣低剂量,每日灌服淫羊藿黄酮（75 mg·kg-1）;E组：去势垣中剂量,每日灌服淫羊藿黄酮（150 mg·kg-1）;F组：去势垣高剂量,每日灌服淫羊藿黄酮（300 mg·kg-1）。实验第4月末处死大鼠,取出大鼠双侧胫骨、双侧股骨、双侧肱骨和全部腰椎。实验动物干预完毕后测定：淤第四腰椎体力学性能指标中弹性模量、最大载荷、最大应力、变形位能、结构刚度,于股骨结构力学性能指标中最大载荷、破坏载荷、变形位能、结构刚度,盂股骨材料力学性能指标中弹性模量、最大应力、最大应变、破坏应力、破坏应变。结果：与B组比较,A、D、E、F组第四腰椎体力学性能指标中弹性模量、最大载荷、最大应力、变形位能、结构刚度,股骨结构力学性能指标中最大载荷、破坏载荷、变形位能、结构刚度,股骨材料力学性能指标中弹性模量、最大应力、最大应变、破坏应力明显升高（P<0.05）;C组有升高趋势;A、C、D、E、F组之间比较差异没有统计学意义;D、E、F组随淫羊藿黄酮剂量的增加而增加,但其相互之间差异没有统计学意义;股骨材料力学性能指标中破坏应变A、C、D、E、F组之间相互比较差异没有统计学意义;表明去势造成了大鼠椎骨力学性能,股骨结构力学性能和股骨材料力学性能的降低,应用淫羊藿黄酮可改善第四腰椎体力学性能、股骨结构力学性能和股骨材料力学性能。结论：淫羊藿黄酮可有效防治去势大鼠骨生物力学性能的降低,使其维持在较高水平。