腰椎间盘突出症患者行腰椎牵引时对血压的影响

目的探讨腰椎间盘突出症患者行腰椎牵引时对血压的影响。方法对46例腰椎间盘突出症患者行腰椎牵引术的临床数据进行回顾性总结。结果46例患者在牵引过程中的不同时间内血压均有升高。结论腰椎牵引过程中细心观察患者变化，随时监测血压是预防因牵引造成意外发生不可缺少的措施。     

骨牵引针道感染的相关因素研究

目的　探讨分析骨牵引针道感染的相关因素。方法　对 12 0例应用骨牵引治疗的患者的针道分泌物或渗出物进行细菌培养 ,同时拟对 11个感染的相关因素进行临床分析和单因素、多因素非条件logistic回归分析。结果发生针道感染 11例 ,感染率 9.0 %。针道感染主要危险因素是固定时间 ,伤情 ,合用激素与否 ,和有无伴有糖尿病。结论　针道感染的高危因素为固定时间 ,伤情 ,合用激素与否 ,和有无伴有糖尿病。因而 ,对有高危因素存在的骨牵引治疗者牵引针的针道要监测各项感染指标 ,避免针道感染的发生。     

A new bubble oxygenator (OCVC oxygenator): Development and clinical application

A new bubble oxygenator, designed for simple operation and clinical efficacy in intracardiac surgery, has been developed and clinically evaluated. This device is characterized by an oxygenating chamber with controllable blood-volume, integral heat exchanger and two-stage microfilter of gravity drainage system, an apparatus for creating and uniformly distributing oxygen bubbles, and construction materials of the device known to be minimally traumatic to the blood. Clinical experience in 132 infantile and pediatric open heart procedures has demonstrated its effectiveness as measured by embolic complications and simplicity in maintaining physiologic blood gas levels.     

The role of vasculature and angiogenesis for the pathogenesis of degenerative tendons disease

More than 100 years ago Wilhelm Roux (1895) introduced the term "functional adaptation to anatomy and physiology". Compared with other organ systems the functional adaptation processes are best identifiable in the locomotor system, like for example in the two types of tendons: traction and gliding tendons. Traction tendons are tendons where the direction of pull is in line with the direction of the muscle (e.g. Achilles tendon). Gliding tendons (e.g. tibialis posterior tendon) change direction by turning around a bony or fibrous hypomochlion. In this region the tendon is subjected to intermittent compressive and shear forces and the extracellular matrix consists of avascular fibrocartilage. Avascularity is considered to be a key factor for the etiology of degenerative tendon disease. The repair capability after repetitive microtrauma is strongly compromised in avascular tissue of gliding tendons. Reduced vascularity is not a specific feature of gliding tendons; several studies have shown that the number and size of blood vessels are largely shortened in the waist of the Achilles tendon. However, histological biopsies from degenerated Achilles tendons and Doppler flow examinations revealed a high blood vessel density in patients with degenerative tendon disease. Angiogenesis is mediated by angiogenic factors and recent studies have shown that the vascular endothelial growth factor (VEGF) is highly expressed in degenerative Achilles tendons, whereas VEGF expression is nearly completely downregulated in healthy tendons. Several factors are able to upregulate VEGF expression in tenocytes: hypoxia, inflammatory cytokines and mechanical load. Since VEGF has the potential to stimulate the expression of matrix metalloproteinases and inhibit the expression of tissue inhibitors of matrix metalloproteinases tissue inhibitor of metalloproteinases (TIMP) in various cell types (e.g. endothelial cells, fibroblasts, chondrocytes), this cytokine might play a significant role for the pathogenetic processes during degenerative tendon disease. An animal experiment in the rabbit has shown that local injection of VEGF reduced the material properties of the Achilles tendon. These experimental findings are in accordance with clinical results that a locally administered (in the area with neovascularization) sclerosing drug (Polidocanol) has a beneficial effect on chronic mid-portion Achilles tendinosis. In conclusion, decreased and increased vascularity might be involved in the pathogenesis of degenerative Achilles tendon disease.     

In vitro evaluation of the effect of core diameter for removing radicular post with ultrasound

The removal of radicular posts for endodontic reasons as well as their replacement is a common procedure in dental practice. The use of ultrasound is becoming a standard practice since it reduces the stress to displace the core from the canal minimizing the risks of root fractures, perforations and further wearing of dental structure. Thus, the objective of this study was to evaluate the effect of a reduction in the core diameter when removing radicular posts with ultrasound. Twenty-four teeth were divided in two groups. Group I received posts with the dowel and core of the same diameter (1.7 mm) and group II received posts with the dowel diameter 2 mm larger (3.7 mm) than the core diameter. Zinc phosphate cement was used to cement the posts in all groups. Half of the samples of each group received ultrasonic energy for 8, 2 min for each face. All samples were submitted to traction on an Instron machine (model 4444). Data were analysed statistically with anova and the Tukey test, revealing significant differences (P < 0.05) between groups. The authors concluded that the mean tension necessary to displace the posts from the roots was reduced by 26% when ultrasound was applied. The reduction of the post-diameter reduced the necessary tension to remove them by 24% compared with larger posts.     

The Tension Mounts: Mechanics Meets Morphogenesis and Malignancy

The tissue microenvironment regulates mammary gland development and tissue homeostasis through soluble, insoluble and cellular cues that operate within the three dimensional architecture of the gland. Disruption of these critical cues and loss of tissue architecture characterize breast tumors. The developing and lactating mammary gland are also subject to a plethora of tensional forces that shape the morphology of the gland and orchestrate its functionally differentiated state. Moreover, malignant transformation of the breast is associated with dramatic changes in gland tension that include elevated compression forces, high tensional resistance stresses and increased extracellular matrix stiffness. Chronically increased mammary gland tension may influence tumor growth, perturb tissue morphogenesis, facilitate tumor invasion, and alter tumor survival and treatment responsiveness. Because mammary tissue differentiation is compromised by high mechanical force and transformed cells exhibit altered mechanoresponsiveness, malignant transformation of the breast may be functionally linked to perturbed tensional-homeostasis. Accordingly, it will be important to define the role of tensional force in mammary gland development and tumorigenesis. Additionally, it will be critical to identify the key molecular elements regulating tensional-homeostasis of the mammary gland and thereafter to characterize their associated mechanotransduction pathways.     

Kinematics of treadmill locomotion in rats conceived, born, and reared in a hypergravity field (2 g). Adaptation to 1 g

The kinematics of treadmill locomotion in rats conceived, born, and raised in a hypergravity environment (HG: 2 g) until the age of 3 months was investigated for 5 weeks after their exposition to earth’s gravity. The locomotor performance of the HG rats (N=7) was compared to that of age-matched control rats (N=8) housed at 1 g for the same period. Kinematic analysis of treadmill locomotion was performed up to 35 days of terrestrial life by an optoelectronic motion analyzer (ELITE system). Results showed that the HG rats exhibited a faster locomotor rhythm (increased number of steps/s), walked closer to the ground, and had a more dorsiflexed foot position. Also, HG rats had shorter steps. The data also highlight a fast adaptation to normal gravity since all the locomotor parameters returned to normal values within 3 weeks. The locomotor modifications may be seen as the persistence of a hypergravity-induced posturo-locomotor adaptation in the centrifuge and/or to more functional changes of sensorimotor systems. Because locomotor performance of HG rats is not severely affected, it is concluded that early development of locomotion processes is highly resistant to gravito-inertial changes.     

Regression of juvenile idiopathic scoliosis

For a young scoliotic boy the customary "wait and watch" management program for rapidly progressive juvenile idiopathic scoliosis was considered unsatisfactory in view of the poor prognosis. The management program devised was based on the congenital postural induction concept of scoliosis with progression accruing from mechanically induced bioengineering fatigue, cumulative molecular scissions, laxity of ligaments, and secondary bone deformation. A coexisting pelvic tilt with restricted movement of the hip and shoulder joints was overlooked initially. Possibly induced simultaneously with the scoliosis, it is considered a contributory factor in scoliosis progression and requires early diagnosis and correction. The rapid improvement in this child's spinal status achieved by physiological traction and specifically designed exercises was such that as a preventive measure the technique warrants further clinical assessment on young scoliotics.     

Remodeled-matrix contraction by fibroblasts: numerical investigations

It is well known that the fibroblast-collagen-matrix contraction model is a unique way to study mechanical interactions that regulate wound contraction of connective tissue cells. This contraction, due to cell traction, plays important roles in wound healing and pathological contractures. A continuum model initially used for the study of mesenchymal morphogenesis is revisited and numerically investigated by assuming that the extracellular matrix has adaptive-elastic properties. The set of non-linear partial differential equations is solved numerically by a finite difference method and the obtained results are discussed.     

Resting Discharge Patterns of Macular Primary Afferents in Otoconia-Deficient Mice

Vestibular primary afferents in the normal mammal are spontaneously active. The consensus hypothesis states that such discharge patterns are independent of stimulation and depend instead on excitation by vestibular hair cells due to background release of synaptic neurotransmitter. In the case of otoconial sensory receptors, it is difficult to test the independence of resting discharge from natural tonic stimulation by gravity. We examined this question by studying discharge patterns of single vestibular primary afferent neurons in the absence of gravity stimulation using two mutant strains of mice that lack otoconia (OTO−; head tilt, het-Nox3, and tilted, tlt-Otop1). Our findings demonstrated that macular primary afferent neurons exhibit robust resting discharge activity in OTO− mice. Spike interval coefficient of variation (CV = SD/mean spike interval) values reflected both regular and irregular discharge patterns in OTO− mice, and the range of values for rate-normalized CV was similar to mice and other mammals with intact otoconia although there were proportionately fewer irregular fibers. Mean discharge rates were slightly higher in otoconia-deficient strains even after accounting for proportionately fewer irregular fibers [OTO− = 75.4 ± 31.1(113) vs OTO+ = 68.1 ± 28.5(143) in sp/s]. These results confirm the hypothesis that resting activity in macular primary afferents occurs in the absence of ambient stimulation. The robust discharge rates are interesting in that they may reflect the presence of a functionally ‘up-regulated’ tonic excitatory process in the absence of natural sensory stimulation.