Evaluation of the treatment of idiopathic clubfoot by using the Ponseti method

The initial treatment of congenital idiopathic talipes equinovarus (clubfoot) is most often nonsurgical. However, surgical treatment in the form of posteromedial release is often undertaken after failure of conservative measures. The prevalence of both immediate and long-term complications in surgically treated clubfeet has cultivated a renewed interest in nonsurgical treatment. The Ponseti method for treating clubfoot has seen a revived interest among those caring for infantile clubfeet. We report on our first 34 infants (57 clubfeet) treated by using the techniques and principles described by Ponseti. Using a standard scoring system, 54 of 57 clubfeet were successfully corrected without requiring posteromedial release. Only 2 patients (3 clubfeet) required extensive surgical correction. There were 6 relapses. In all recurrent cases, there was a lack of compliance with the straight-last shoe and foot abduction bar regimen. Based on this level of initial success, we believe that posteromedial release is no longer necessary for the majority of cases of congenital clubfeet.     

Blood vessels in epiphyseal cartilage of human fetal femoral bone: a scanning electron microscopic study of corrosion casts

Formation of intrachondral vessels (cartilage canals) in the proximal femoral epiphysis was studied in 13- to 22-week-old human fetuses using a corrosion casting technique and scanning electron microscopy. Several successive morphological stages of angiogenesis occurring inside the hyaline cartilage were distinguished. The process of cartilage vascularization starts with the formation of hairpin loops sent off from the perichondrial vascular network into the adjacent cartilage. A capillary glomerulus is then formed at the leading end, and the entire vascular unit grows in length, assuming a mushroom-like shape. Its further elongation is accompanied by a backward expansion of the capillary network which surrounds a pair of main vessels (arteriole and venule) like a manchette. The subsequent branching of such primary vascular units proceeds according to the same morphological patterns. The resulting tree-like vascular formations become interconnected via their lateral branches. This study clearly supports the invasion theory of cartilage canal formation.     

三种基牙材料对铸造玻璃瓷冠碎裂影响的研究

目的:研究不同种类和强度基牙材料与瓷冠破折碎裂的内在关系.方法:选用计算机建立上颌中切牙的三维有限元模型,模拟陶瓷层、牙本质、核桩等结构.分析在天然齿基牙、钴铬合金基牙及复合树脂基牙情况下,铸造玻璃陶瓷全冠的瓷层内及残余牙本质的应力分布情况.结果:高弹性模量的钴铬合金能够降低瓷层及残余牙本质内的最大主应力和最小主应力峰值,防止瓷层破折碎裂;而弹性模量与牙本质相近的复合树脂桩降低应力峰值的作用不明显.结论:对于有牙髓活力的牙本质基牙,尽量保存牙髓活力后行全冠修复.对于行根管治疗术后的无髓牙,进行核桩冠修复时,采用高弹性模量的高熔合金,尽量避免使用弹性模量较小的复合树脂核.     

辐射对豚鼠鼻黏膜组织结构及微血管的影响

目的：探讨辐射对豚鼠鼻黏膜结构及微血管的损伤。方法：选择健康豚鼠84只，随机分为对照组（12只）及照射组（72只）。均在同样条件下喂养。将照射组豚鼠置于直线加速器射线内照射，每周1次，每次照射5Gy，计3周，总剂量15Gy，建立辐射损伤动物模型。分别于照射后0．5、1.0、2．0、3．0、5．0、6．0个月处死动物12只，随机取6只做鼻腔黏膜微血管铸型，另6只做病理检查。对照组在假照射后6个月处死动物，随机各选6只分别做鼻黏膜微血管铸型检查和病理检查。结果：照射组豚鼠的鼻黏膜辐射后早期表现为急性炎症反应，黏膜大量坏死、脱落，电镜下见仅少部分黏膜表面还被覆着正常的纤毛结构。以后黏膜开始修复，至6个月时基本结束，但大部分黏膜失去了正常的纤毛柱状上皮结构特点，部分区域甚至代为组织转化的鳞状上皮；微血管铸型可见，早期改变为毛细血管扩张充血及血管内皮细胞肿胀，以后逐渐出现毛细血管的扭曲变形、闭塞及中断，毛细血管数量大量减少，致血液回流障碍，微静脉萎瘪。后期部分区域出现新生的毛细血管，但结构紊乱，不具备微循环的功能。结论：鼻黏膜的损伤、晚期的鳞状上皮组织转化以及鼻黏膜微循环的破坏是放疗后鼻腔功能障碍的病理学基础。     

金属表面TiO2薄膜的溶胶-凝胶法制备及其血液相容性研究

通过溶胶 凝胶法制备TiO2 薄膜对 316L不锈钢和NiTi形状记忆合金进行表面改性处理。研究发现 ,经 5 0 0℃处理 1h的薄膜结构致密 ,膜层均匀平滑 ,薄膜主要由锐钛矿相TiO2 构成 ,随热处理温度的提高 ,锐钛矿相逐渐转变为金红石相。电化学腐蚀和动态凝血时间及溶血率测试表明 ,通过溶胶 凝胶法制备TiO2 膜进行表面改性的 316L不锈钢和NiTi合金的抗模拟体液腐蚀性提高 ,动态凝血时间延长 ,溶血率下降 ,说明溶胶 凝胶法制备TiO2 膜可以提高金属植入物的血液相容性     

Willis环形态与功能对照研究

目的：从不同角度分析Willis环的形态学变异及其功能状况。方法：分别采用脑尸解标本、血管铸型标本及动态血管造影资料进行Willis环的对比分析。结果：正常成人组尸体与活体Willis环分型无差异；活体正常组与活体病理组Willis环的比较有差异；活体正常组与活体病理组PCA供血类型有差异。结论：胎儿与成人、尸体与活体、静态与动态、正常与异常的有机结合能全面评价Willis环的形态学变异及其功能状况，为临床正确诊治脑血管病提供基础依据。     

Identification of vascular sphincters at the junction between alveolar capillaries and pulmonary venules of the mouse lung

Background: A peculiar feature of lung circulation in the lung is the pronounced variations in blood volume observed in alveolar capillaries that occur because of the changes in the conformation of the alveolar wall that are associated with the respiratory movements. This phenomenon has led to the postulate that mechanisms of postcapillary control of blood flow are to be present in the lung vessels. In the present study we searched for microanatomical evidence of vascular sphincters in the deep lung tissue of mice, namely in alveolar capillaries and pulmonary veins. Methods: We have used scanning electron microscopy (SEM) to examine two types of samples of normal lung tissue of CD-1 mice: 1) vascular corrosion casts made by vascular perfusion with Mercox® resin, and 2) routinely made gold/platinum-coated replicas of sectioned lung tissue. Results: Careful scrutiny of the vessels of the deep lung tissue led to the identification of sphincters in alveolar capillaries. These sphincters were located at the junction between capillary and pulmonary veins. They corresponded to areas to the vascular wall showing circular swellings where a radial organization was observed, since they were made up of alternating grooves and bulges. Transmission electron microscopy showed that smooth muscle cells participated in the formation of the sphincters. Conclusions: Our data reveal a new location for vascular sphincters in pulmonary vessels and, because these novel sphincters are located at the capillary-vein junction, they offer a structural setting for the existence of postcapillary control of blood flow in the pulmonary circulation of mice. © 1995 Wiley-Liss, Inc.     

Performance of platinum stimulating electrodes,mapped on the limitvoltage plane

The paper introduces the electrode limit-voltage plane (ELVP)—a useful tool for describing in electrical terms what a polarisable electrode is doing under a particular set of conditions. The ELVP is then used to consider the charge-injection capability of a platinum stimulating electrode.     

Electrochemical release testing of nickel-titanium orthodontic wires in artificial saliva using thin layer activation

Alloys based on Ni–Ti intermetallics generally exhibit special shape memory and pseudoelastic properties, which make them desirable for use in the dental field as orthodontic wires. The possibility of nickel release from these materials is of high concern, because the allergenicity of this element. The aim of this study was to test pseudoelastic Ni–Ti wires in simulated physiological conditions, investigating the combined effect of strain and fluoridated media: the wires were examined both under strained (5% tensile strain) and unstrained conditions, in fluoridated artificial saliva at 37 °C. Real time electrochemical nickel release testing was performed using a novel application of a radiotracer based method, thin layer activation (TLA). TLA was validated, in unstrained conditions, against adsorptive stripping voltammetry methodology. Control tests were also performed in non-fluoridated artificial saliva. From our research it transpired that the corrosion behaviour of Ni–Ti alloy is highly affected by the fluoride content, showing a release of 4.79 ± 0.10 μg/cm²/day, but, differently from other biomaterials, it does not seem to be affected by elastic tensile strain. The application of the TLA method in the biomedical field appears a suitable technique to monitor in real time the corrosion behaviour of biomedical devices.     

Microvasculature of regular and irregular areolae of the areola-gland subunit of the porcine placenta: structural and functional aspects

To examine the vasculature of the areola-gland subunit of advanced pig placenta, tissues from ten animals between 43 and 112 days of gestation were prepared for histology and for scanning electron microscopy of vascular corrosion casts from both maternal and fetal sides. Regular areolae, tributary to one gland only, are round with a wide-meshed and smooth subepithelial capillary network on the maternal side, which is similar to the pre-implantative stage and bordered by an abrupt rim towards the interareolar maternal capillary network. On the fetal side, the capillary network follows papillae which protrude into the areolar cavity or converge to form a ring towards the areolar periphery. Irregular areolae, in contrast, have indistinct boundaries and are characterized by two or more gland openings. The maternal capillary network has moderate density and follows the corrugations, whereas the fetal capillary network is basically two-dimensional with some blunt sinusoidal protrusions. Vessel architecture of both areolar types implies facilitated external inflow of blood into the areola on arteriolar as well as on capillary levels, whereas the outflow from the areolar capillaries comprises venules converging into one or two areolar stem veins, and therefore conducts venous blood in a manner different from that of the interareolar region. It is suggested that this arrangement could favour vascular control mechanisms in uterus, placenta and fetus. On the basis of these observations and the discussion, it is suggested that these areolaspecific vessel systems are important for sustaining the characteristic substance transfers in the areola, the secretion, metabolism and absorption, which according to the literature are not the same in the regular as in the irregular areolar type of the porcine areola-gland subunit of the placenta.