玻璃化保存法对肌腱形态学及生物力学影响

目的:探讨玻璃化保存法对兔肌腱组织、细胞形态及力学性能的影响。方法:以18.64%二甲基亚砜(V/V)+13.37%乙酰胺(V/V)+9.17%1,2丙二醇(V/V)+0.10 mmol/L海藻糖+10%小牛血清为玻璃化冷冻保护剂,将新西兰纯种大白兔肌腱采用三步法预处理,-196℃液氮保存14 d作为玻璃化保存组;以15%二甲基亚砜+10%小牛血清作为冷冻保护剂,"两步法"处理后-196℃液氮冷冻保存14 d的新西兰纯种大白兔胫前肌肌腱作为对照组,透射电镜观察组间肌腱组织细胞的形态差异,并分别进行肌腱拉伸实验,检测肌腱破坏载荷峰值、最大载荷拉伸位移及杨氏弹性模量。结果:玻璃化保存组细胞的结构形态未见明显改变,对照组肌腱组织微观结构损伤明显。肌腱破坏荷载峰值:玻璃化保存组与对照组无统计学意义(P=0.256);最大载荷拉伸位移:玻璃化保存组与对照组间差异无统计学意义(P=0.065);杨氏弹性模量:玻璃化保存组与对照组间差异有统计学意义(P=0.006)。结论:与对照组肌腱相比,玻璃化保存法对肌腱组织细胞形态损伤较小,但两者在生物力学特性上无明显差异。

仙珍骨宝干预泼尼松诱发大鼠的骨丢失

背景:仙珍骨宝胶囊由蛇床子、淫羊藿等制成,对糖皮质激素、维甲酸等诱发的骨质疏松有一定的预防作用。目的:建立泼尼松诱发大鼠骨质疏松模型,通过骨形态计量学和骨生物力学等方法探讨仙珍骨宝对大鼠不同部位骨骼的影响。方法:32只SD大鼠随机分成对照组、模型组和仙珍骨宝高、低剂量组。后3组给予泼尼松3.5mg/(kgd)灌胃建立骨质疏松模型。仙珍骨宝高、低剂量组大鼠在泼尼松灌胃1h后给予仙珍骨宝胶囊0.95g/(kgd)、0.475g/(kgd)。结果与结论:与对照组比较,模型组大鼠股骨骨密度、弹性载荷、最大载荷和断裂载荷均下降,胫骨上段动态参数标记周长百分数、骨表面形成率、骨转换率均降低,但静态参数骨小梁面积百分数、骨小梁数量、骨小梁厚度和骨小梁分离度无明显变化。胫骨中段皮质骨形态计量学参数均无明显变化。与模型组比较,仙珍骨宝高剂量组股骨密度、骨生物力学参数,胫骨上段标记周长百分数、骨表面形成率和骨转换率增加,但胫骨中段的骨形态计量学参数无明显变化。与模型组比较,仙珍骨宝低剂量组各项参数均无明显变化。提示高剂量仙珍骨宝促进骨形成,可预防泼尼松所致大鼠股骨骨密度及生物力学的降低,但对胫骨中段皮质骨无明显影响。

早期圆锥角膜的诊断方法

圆锥角膜是好发于青春期、以角膜突出变薄并向前呈锥形突起为特征的致盲性眼病。进展期圆锥角膜较易通过临床症状及眼前节检查发现,而早期圆锥角膜(包括可疑圆锥角膜、亚临床圆锥角膜、顿挫型圆锥角膜)由于视力下降不明显、角膜改变较轻微,难以通过一般检查发现,目前通常采用角膜地形图进行判断。相干光断层扫描作为另一种角膜形态学检测方法,逐渐受到重视,作为角膜地形图的辅助诊断手段。眼反应分析仪及Corvis ST设备通过测量眼生物力学参数,可发现早于形态学变化的角膜结构改变。以上方法均可得到数量可观的参数,人工智能技术目前已尝试用于探索圆锥角膜参数的变化规律,有助于实现早期诊断。此外,易感基因及生物标志物的发现将有助于筛查高风险人群,提醒定期检查、尽早发现异常并干预。

Study of the morphology and biomechanics of sacral fracture

Objective： To characteristics of sacral loads. observe the morphological fracture under different impact Method： Ten fresh pelvic specimens were loaded in dynamic or static state. A series of mechanical parameters including the pressure strain and velocity were recorded. Morphological characteristics were observed under scanning electron microscope. Results： The form of sacral fracture was related to the impact energy. Under low-energy impact loads, ilium fracture, acetabulum fracture and crista iliaca fracture were found. Under high-energy impact loads, three types of sacral fracture occurred according to the classification of Denis： sacral ala fracture, Type 1 fracture; sacral foramen cataclasm fracture, Type lI fracture; central vertebral canal fracture, Type m fracture. Nerve injury of one or two sides was involved in all three types of sacral fracture. The fracture mechanism of sacrum between the dynamic impact and static compression was significantly different.When the impact energy was above 25 J, sacral foramen cataclasm fracture occurred, involving nerve root injury. When it was below 20 J, ilium and sacral fracture was most likely to occur. When it was 20 - 25 J, Type l fracture would occur. While in the static test, most of the fracture belonged to ilium or acetabulum fracture. The cross section of sacrum was crackly and the bone board of Haversian system was brittle, which could lead to separation of bone boards and malposition of a few of cross bone boards. Conclusions： In dynamic state, sacrum fracture mostly belongs to Type I and Type lI, and usually involves the nerve roots. Sacrum fracture is relevant to the microstructures, the distribution of the bone trabecula, the osseous lacuna and the Haversian system of sacrum. The fracture of ilium and acetabulum more frequently appears in static state, with slight wound of peripheral tissues.