可吸收羟基磷灰石/聚DL-乳酸骨折内固定材料机械强度和生物降解性研究

目的评价自行研制的可吸收羟基磷灰石/聚DL-乳酸(HA/PDLLA)复合骨折内固定材料的机械强度和生物降解性。方法体外降解实验是把相同分子量的HA/PDLLA和单纯PDLLA试件分别置于PBS缓冲液中,于2、4、6、8、10、12周取材,测试生物降解率、吸水率、失重率、机械强度及降解液pH值,并作扫描电镜(SEM)观察;体内实验是用一枚HA/PDLLA棒内固定兔股骨髁松质骨部横形截骨,作X线摄片、组织学、机械强度及材料骨界面SEM观察。结果HA/PDLLA复合材料较单纯PDLLA材料降解速度减慢,机械强度提高,骨折正常愈合。结论HA/PDLLA材料具有足够的强度保证实验性松质骨骨折正常愈合。     

消旋聚乳酸/ 羟基磷灰石复合材料成骨性的体内实验研究

 目的 探讨消旋聚乳酸/羟基磷灰石（PDLLA/HA）复合材料在动物体内的生物相容性和成骨性。 方法 将 66 只日本大耳兔随机为 3 组，每组 22 只。其中 2 组分别于股骨髁间植入 PDLLA/HA 复合材料圆柱棒（PDLLA/HA 组）和 PDLLA 圆柱棒（PDLLA 组），1 组仅手术而不植入材料作为对照组。术后 3、6 周植入部位摄 X 线片观察植入材料的变化及其与周围组织的结合情况；术后 3、6、12、24 周每组各处死 5 只兔，进行植入部位大体解剖学观察和组织病理学观察。 结果 术后 X 线观察显示 PDLLA/HA 组植入材料显影良好，与周围组织有明显界限；而 PDLLA 组可以看到明显的孔道。大体解剖学和组织病理学观察显示 PDLLA/HA 组术后早期局部炎症反应明显轻于 PDLLA 组，材料与周围组织结合紧密，膜外有少许新骨生成；6 周时膜外新骨增多；12 周时复合螺钉周围有少量新生骨小梁形成，边缘附有大量的成骨细胞；24 周时可见纤维组织长入材料，材料色、形、质与周围结缔组织相近。而 PDLLA 组材料降解明显，12 周后已不能维持棒体形状。 结论 PDLLA/HA 复合材料具有良好的生物相容性和体内成骨性。     

透明质酸钠复合重组人骨形态发生蛋白2注射剂对下颌骨量的扩增作用

背景:对牙槽骨骨量需要扩增的患者而言,固态的支架材料并不太适用。寻找具有流动性和黏附能力、不占体积的材料是目前研究热点。目的:观察透明质酸钠(sodium hyaluronate,SH)复合重组人骨形态发生蛋白2(recombinant human bone morphogenetic protein,rhBMP-2)注射剂对兔下颌骨量的扩增作用。方法:60只兔按随机区组设计分为4组:rhBMP-2-SH组、rhBMP-2组、SH组分别于双侧下颌骨膜下置入rhBMP-2-SH复合物0.2mL、rhBMP-20.5mg、SH0.2mL。空白对照组双侧均切开后不作处理即关闭伤口。术后第2,4,8周分批处死动物。处死前作99Tcm-MDP骨显像;处死后切取标本作苏木精-伊红染色观察、胶原I免疫组化、碱性磷酸酶活性、骨钙素含量检测。结果与结论:①rhBMP-2-SH组99Tcm-MDP骨显像下颌骨感兴趣区计数比值于2,8周时高于其他各组(P0.05),4周时明显高于其他各组(P0.01)。②组织学观察rhBMP-2-SH组于术后2周即有新生骨小梁生成,至8周钙化成板层骨块,并且4周时可见透明软骨细胞出现,胶原Ⅰ免疫组化只在2周骨基质中呈强阳性表达。③rhBMP-2-SH组碱性磷酸酶活性指数明显高于其他各组(P0.01);并随着时间延长而逐渐增高(P0.01)。④rhBMP-2-SH组骨钙素含量于4周及8周时明显高于其他各组(P0.01),并随着时间延长而逐渐增高(P0.01)。提示rhBMP-2-SH注射剂能于兔下颌骨表面稳定地形成新骨从而达到骨量扩增效应。成骨方式为混合型成骨方式,以膜内成骨为主。     

可变刚度可降解-DL-聚乳酸泡沫衬垫材料与钛合金组成接骨板系统治疗胫骨骨折

背景：理想的骨折固定系统,在骨折早期应能达到坚强固定,后期要能防止应力遮挡作用诱发的固定骨段的骨质疏松。可降解骨科内固定材料无疑为此种骨折固定系统提供了理论可能。 目的：旨在评估自制可变刚度接骨板系统(由可降解聚-DL-乳酸泡沫衬垫材料和钛合金接骨板组成)对兔胫骨干中段骨折的固定效果和对骨折愈合的影响。 方法：新西兰大白兔64只采用随机数字表法分为实验组和对照组,线锯造成兔右侧胫骨中段骨折模型。用相对分子质量为 200 000的自制超高相对分子质量聚乳酸材料膜垫(厚1 mm)和4孔钛合金Tc4接骨板制作成可变刚度接骨板系统固定实验组兔胫骨中段骨折,以单纯Tc4钛合金接骨板固定对照组。于第2,4,8,12周处死动物,从大体观察、X射线平片、组织学和骨生物力学等方面观察和评定骨折愈合情况。 结果与结论：X射线及大体标本示术后两组对位效果佳,无移位。组织学观察可见术后同期实验组标本较对照组标本骨痂内骨小梁排列紧密、髓腔开通完全、新生骨组织改塑重建完整。生物力学结果显示8周时两组愈合骨最大抗弯曲强度差异无显著性意义。12周时实验组愈合骨抗弯曲刚度优于对照组。提示自制可变刚度接骨板系统用于兔胫骨骨折固定效果可靠,有利于骨折段骨痂改塑重建,利于骨折愈合,用于骨折内固定治疗效果优于单纯钢板,为其进一步临床应用研究提供了实验依据。     

外源性碱性成纤维细胞生长因子促膜引导性骨再生的实验研究

本实验旨在评估碱性成纤维细胞生长因子 (bFGF)对于膜引导性骨再生 (MGBR)的作用。取 4 0只成年新西兰大白兔 ,以聚 DL 乳酸膜建立经典的兔桡骨缺损膜引导性骨再生模型 ,实验侧膜管内加入游离bFGF4 0 μg/10 0 μl,对照侧膜管内加入 10 0 μl的生理盐水。术后 2、4、8、12周分别处死动物 ,行大体观察、X线摄片、组织学观察和图像分析以及骨生物力学检测。术后 2周 ,可见隔膜两端的软组织已覆盖隔膜管 ,使其形成完全密闭的腔室 ,术后 12周PDLLA膜管仍保持完整的外形。组织学显示 :术后 2周 ,bFGF组两骨断端均有较多的新生骨小梁形成 ,术后 12周 ,bFGF组缺损完全愈合 ,开始重塑改建。术后 2周、4周 ,bFGF组膜管内新生骨小梁平均面积、直径均与空白对照组比较明显增加 (P <0 .0 5 ) ,术后 8周和 12周 ,两组膜管内骨小梁平均面积、直径差异无显著性 (P >0 0 5 )。 12周时除了破坏挠度值 ,bFGF组新生骨生物力学指标优于对照组 (P <0 .0 5 )。因此 ,作者认为外源性bFGF能够促进MGBR及其生物力学性能的恢复。     

聚乳酸螺钉对骨折愈合影响的实验研究

本实验旨在研究一种自制PDLLA螺钉对骨折愈合的影响。用自制粘均分子量达 43× 10 4 的PDLLA螺钉内固定治疗 8只犬股骨外髁骨折 ,并以金属螺钉固定为对照。动物术后 2、4、8、12周处死 ,观察骨组织愈合影响的光镜和扫描电镜表现。光镜示两组骨折 2周时形成大量纤维性骨痂 ,12周时都已顺利愈合 ,实验组成骨过程明显较对照组缓慢 ,但成骨活动正常。扫描电镜示两组胶原纤维都排列规则 ,12周时顺利钙化成骨 ,实验组 12周时见大小不等 ,高电子密度颗粒。因而临床上应当适用于血供丰富部位骨折。     

天鹅记忆接骨器对实验性骨折愈合过程中局部IGF-Ⅰ含量的影响

目的研究天鹅记忆接骨器（SMC）内固定对兔肱骨骨折愈合过程中局部IGF-Ⅰ的含量的影响,探讨SMC对骨折愈合过程的影响。方法随机选择兔一侧肱骨,截骨后SMC固定,为实验组。对侧肱骨同法截骨后,在相应位置用动力加压接骨板DCP固定,为对照组。术后第2、3、4、6、8、12周分别处死动物,以骨折线两侧0.5cm范围内为取材区。分别测定不同时间各组骨标本中IGF-Ⅰ含量。结果实验组骨折局部IGF-Ⅰ含量在术后2w逐渐增高,6w时达到顶峰,8～12wIGF-Ⅰ含量逐渐下降;DCP组骨折局部IGF-Ⅰ含量在术后2w逐渐增高,8w时达到顶峰,12周IGF-Ⅰ含量下降。两组间相比,术后3、4、6周,SMC组骨折局部IGF-Ⅰ含量明显高于DCP组,4周时差异最大。结论SMC较DCP更能促进骨折局部IGF-Ⅰ的分泌,促进骨折愈合。     

体外冲击波联合增强型纤维蛋白胶负载骨生长因子治疗兔骨不连的研究

目的:欲评价体外冲击波联合增强型纤维蛋白胶负载骨生长因子经皮直接注射入骨折断端加速骨不连愈合、促进成骨过程的作用。方法:48只兔使用单纯随机抽样的方法分为4组,制备共48侧桡骨模型,并行不同方案的治疗:A组12只骨不连兔只给予ESW治疗;B组12只骨不连兔给予ESW联合纤维蛋白胶(Fibrin Glue,FG)治疗;C组12只骨不连兔给予ESW联合FG/骨形态发生蛋白-2(Bone morphogenetic protein-2 rh BMP-2)/重组人碱性成纤维生长因子(recombinant human basic fibroblast growth factor,rhb FGF)治疗;D组12只骨不连兔给予ESW联合FG/rh BMP-2/rhb FGF/人重组血管内皮细胞生长因子(recombinant human vsacular endothelial growth factor,rh VEGF)治疗。联合治疗后,应用常规X线摄片、组织形态光学检查及生物力学试验等方法检测冲击波联合药物治疗后的骨折愈合情况。结果:与A组单纯体外冲击波治疗相比,B组FG+体外冲击波治疗组骨折线稍模糊,骨痂面积开始增多,骨折断端距离缩短。组织形态学显示大片软骨形成,软骨细胞增生活跃,周围纤维结缔组织中可见新生血管形成。生物力学测定结果发现两组之间并没有差距,无统计学意义(P0.05)。C组FG/rh BMP-2/rhb FGF+体外冲击波治疗组骨折线模糊,纤维骨痂消失,可见明显增生的骨小梁。与B组:FG+体外冲击波治疗组相比,C组:FG/rh BMP-2/rhb FGF+体外冲击波治疗组生物力学明显有差异,且具有显著性统计学意义(P0.01)。D组:FG/rh BMP-2/rhb FGF/rh VEGF+体外冲击波治疗组4周时骨折线明显模糊,骨小梁明显增多。8周时骨折线消失,且愈合后塑形好。组织形态学显示以纤维结缔组织为主,中间见大量成骨细胞。与C组FG/rh BMP-2/rhb FGF+体外冲击波治疗组相比,差异具有显著性统计学意义(P0.01),说明更能够提高抗弯曲力度。结论:体外冲击波联合经皮注射增强型纤维蛋白胶负载骨生长因子具有促进骨折愈合作用,有望成为一种非手术治疗骨不连的良好方法。     

天鹅记忆接骨器对实验性骨折愈合过程中局部IGF-I含量的影响

目的 研究天鹅记忆接骨器(SMC)内固定对兔肱骨骨折愈合过程中局部IGF-I的含量的影响,探讨SMC对骨折愈合过程的影响.方法 随机选择兔一侧肱骨,截骨后SMC固定,为实验组.对侧肱骨同法截骨后,在相应位置用动力加压接骨板DCP同定,为对照组.术后第2、3、4、6、8、12周分别处死动物,以骨折线两侧0.5cm范围内为取材区.分别测定不同时间各组骨标本中IGF-I含量.结果 实验组骨折局部IGF-I含量在术后2w逐渐增高,6w时达到顶峰,8～12w IGF-I含量逐渐下降;DCP组骨折局部IGF-I含量在术后2w逐渐增高,8w时达到顶峰,12周IGF-I含量下降.两组间相比,术后3、4、6周,SMC组骨折局部IGF-I含量明显高于DCP组,4周时差异最大.结论 SMC较DCP更能促进骨折局部IGF-I的分泌,促进骨折愈合.     

聚DL-乳酸/羟基磷灰石复合材料修复长骨缺损的实验研究

目的 :评价羟基磷灰石 (HA)复合聚DL 乳酸 (PDLLA )制备的材料体内成骨能力。方法 :将PDLLA和PDLLA/HA( 2 0wt % )材料采用盐结晶颗粒沥滤法制成三维多孔材料 ,45例 1cm兔桡骨去骨膜缺损分为三组 ,分别植入 2种材料和作空白对照 ,术后 2 ,4,8,12周行X线、组织学及扫描电镜观察骨生成状况 ,8、12周行生物力学测试 (三点折弯强度 )。结果 :泡沫状PDLLA/HA ( 2 0wt % )材料比纯PDLLA成骨更好 (P <0 .0 5 ) ,实验组与对照组相比差异有显著性 (P <0 .0 5 )。结论 :PDLLA具有良好的生物相容性 ,制成多孔状具有较好的骨传导性能 ,HA( 2 0wt % )的加入促进了多孔PDLLA的骨传导能力 ,提高了骨生成的质量。PDLLA/HA( 2 0wt % )复合材料是一种有临床应用前景的骨移植材料。     

Topical organization of the projections of neurons of the substantia nigra and the ventral field of the tegmentum of the midbrain to the head of the caudate nucleus of the cat

Neuroscience and Behavioral Physiology -     

Asymmetry of the internal connections of the striate cortex of the cat in the projection zone of the center of the field of vision

Studies were carried out on the organization of the internal connections of the striate cortex in cats in the projection zone of the center (0–5°) of the field of vision by microintophoretic application of horseradish peroxidase to electrophysiologically identified orientational columns. The area containing neurons showing retrograde labeling in most cases extended in the mediolateral direction. Labeled cells were located in the upper (II, III) and lower (V, VI) layers of the cortex, and the shapes and orientations of the areas containing labeled neurons in these layers coincided. Spatial asymmetry was detected in the distribution of labeled neurons relative to the orientational column studied. Labeled cells were located predominantly medial to the columns, regardless of the distance from the projection of the area centralis. Considering the visuotopical map of field 17, the asymmetry detected here provides evidence that neurons in orientational columns have more extensive connections with neurons of the peripheral part of the cortex. An asymmetrical distribution of “silent” zones around the receptive fields of neurons in orientational columns is suggested, and that these appear to receive influences from the periphery of the visual field. Laboratory of Visual Physiology and Laboratory of Central Nervous System Morphology, I. P. Pavlov Institute of Physiology, Russian Academy of Sciences, 6 Makarov Bank, 199034 St. Petersburg, Russia. Translated from Fiziologicheskii Zhurnal imeni I. M. Sechenova, Vol. 82, No. 12, pp. 23–29, December, 1996.     

Characteristics of the topographic interrelation of the head of the pancreas and the duodenum and pathology of the organs of the pancreatoduodenal area

Seventy pancreatoduodenal complexes of 55 patients with chronic pancreatitis and tumours of this zone and 15 patients died from other diseases are studies histotopographically . The pieces of the pancreatic head tissue in the medial wall of the duodenum were found in 12 cases of the first group and in 4 control cases. The pancreatic tissue consisted either of all elements of this organ or cystically dilated ducts and seemed to infiltrate different layers of the duodenum wall. Three variants of the pancreatic head structure are suggested on the basis of anatomo-topographical interrelationships of the pancreatic head and duodenum. In 12 out of 14 cases chronic pancreatitis and carcinoma of organs of this zone were combined with the variants of the pancreatic head structure, in 2 cases there was a true heterotopy . Pathogenetic significance of these variants for the development of chronic pancreatitis is discussed.     

Influence of the level of the transmembrane potential on the dynamics of the extinction of the amplitude of the synaptic reactions of the snail under voltage clamping conditions

The influence of the level of the transmembrane potential on the dynamics of the extinction of the amplitudes of summary excitatory postsynaptic currents arising in identified giant parietal neurons in response to rhythmic stimulation of the intestinal nerve was investigated in a preparation of the isolated CNS of the common snail in order to identify the possibility of the participation of the postsynaptic element in synaptic plasticity. It was demonstrated that, at a greater value of the transmembrane potential, the decrease in the amplitudes of the postsynaptic currents which have been induced by rhythmic stimulation takes place more rapidly. It was also demonstrated that at a higher frequency of stimulation of the nerve, the effect of the influence of the membrane potential level on the dynamics of the synaptic reactions is more prominent. The data obtained may be regarded as an argument in favor of the possibility of the participation of the post-synapse in plasticity. This study was partially supported by the Russian Basic Research Fund (project No. 94-04-12209). Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow. Translated from Zhurnal Vysshei Nervnoi Deyatel'nosti imeni I. P. Pavlova, Vol. 45, No. 1, pp. 171–179, January–February, 1995.     

Effects of the lesion of the postcommissural part of the septum on the behavior of the rat.

The effects of the lesion of the postcommissural part of the septum on behavior of the rat has been studied. Results may be summarized as follows. An increase in the exploratory behavior in the open field which decreases rapidly; a decrease in the number of defecations in this test and a decrease in time leaving a dark environment for exploration. In the shuttle box test, no facilitation of the acquisition, but a permanent and quite significant increase in the intertrial activity has been found. We conclude that the lesions tend to decrease the emotivity of the subjects. An interpretation on the basis of the species -- specific defensive reactions explains the transitory and permanent effects of the lesions on the spontaneous activity.     

Effect of the conditions of adaptation of the optic analyzer to the function of the thermoreceptors of the human skin

Summary A discussion is presented of the effect produced by light stimulation applied to the optic analyzer alone on the function of the temperature analyzer. The cutaneous-temperature analyzer was kept on constant illumination and temperature. The light effects from the retinal photoreceptors on the cutaneous thermoceptor system led to reflex changes of the functional rate of the latter. Conditions of the optic analyzer of light adaptation caused reflex adjustment of cold receptors as to heating. Dark adaptation of the eyes changed the functional state of the cold receptors, corresponding to their adjustment to low temperatures.(Presented by Active Member AMN SSSR V. V. Parin) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 57, No. 3, pp. 3–6, March, 1964