2000, 15(1):1-7. DOI: 10.3871/j.1004-7220.2000.1.7.
Abstract:To study the rule of remodeling and the relationship between stress and growth of abdominal aorta in hypotension. Methods A hypotensive model was established in rats by constricting the abdominal aorta below the orifice of the left renal artery. The morphormetric parameters and microstructural components of the abdominal aorta was observed on the tissue slides of the artery in different phases. Results f Hypotension results in a negative increase of morphometric dimension of smooth muscle, collagenic fiber and elastic fiber. Conclusions: The decrease of the wall area occurred earlier than any other parameter, and its tendency of the changes is most stable, it's negative increase rate and total negative increase degree was the greatest at different phases, so the wall area is the characteristic guideline. Among the three microstructural components, Smooth muscle was the most sensitive to stress, it's total negative increase degree was the greatest, it was the important factor of arterial remodeling.
2000, 15(1):8-12. DOI: 10.3871/j.1004-7220.2000.1.12.
Abstract:Cardiovascular and cerebrovascular diseases are in the first place of death rate at present, there are many articles on how to prevent and treat them at early stage to reduce the death rate. The study in this paper is mainly on the change of cerebral circulation dynamics in the elder patients with coronary heart disease whose ventricular function is basically normal. Methods: Taking 60 cases of elder patients with coronary heart diseases and 68 normal cases as comparative group to see the parameters of heart function and cerebral circulation dynamics parameters. Results: among & heart function indexes in coronary heart disease group, only aortic internal diameter has distinguishable reduction, other indexes are normal, but cerebral circulation dynamics parameters have distinguishable change. It mainly shows that both the maximal and minimal blood speed of carotid are reduced; carotid diameter is reduced; pulse index and resistance index are all raised; cerebrovascular and special resistance are increased; nerve self-regulation ability for cerebrovascular function and critical pressure are also all decreased. Conclusion: Though the elder patients with coronary heart disease have not got any brain symptom and sign, their cerebrovascular function has been early damaged. It shows that it is important for the elder patients with coronary heart disease to prevent cerebrovascular diseases at early stage.
2000, 15(1):13-18. DOI: 10.3871/j.1004-7220.2000.01.18.
Abstract:The aim of this study is to predict the cryoinjury that is caused by thermal stresses during cryopreservation of living cells, tissues and organs. A thermal stress analysis model is developed for water freezing process taking place inside acolumn. The model allows us to predict the temperature field and the thermal stress distributions in the ice. The maximum tensile stress occurs during phase change. The radial stresses are less than the circumferential stresses and axial stresses. A quick freeing process results in larger thermal stresses in the ice than a slow freeing process does. When the cooling rate is IK/min the maximal stress is 0.12Mpa; when the cooling rate is 12K/min the maximal stress is 0.6Mpa. If the maximum tensile stress exceeds the failure strength, the crack will initiate on the wall of blood vessel.
2000, 15(1):19-21. DOI: 10.3871/j.1004-7220.2000.01.21.
Abstract:Stress distribution of the spine in upright, flexion and extension postion was analyzed using a three- dimensional finite element model of the spinal motion segment. The stress concentration was noted at the pedicle and the posterosuperior part of the vertebral body near the pedicle. The results indicate that stress concentration of the spine may be implicated in the biomechanical mechanism underlying thoracolumbar burst fractures.
2000, 15(1):22-27. DOI: 10.3871/j.1004-7220.2000.01.27.
Abstract:The inter-vertebral disc is an important part of human lumbar spine, it is valuable for bio-mechanics study of the lumbar spine and inter-vertebral disc. This study indicates that a new inner stress testing way for the inter-vertebral Disc Joints' Core has been provided and it also showed that the new way is an effective method for studing the inter-vertebral Disc Joints' Core. The data prove good results and coincide with another old way's results. All of these provide an estimation and basic theory for the inter- vertebral Disc Joints' Core study.
2000, 15(1):28-32. DOI: 10.3871/j.1004-7220.2000.1.32.
Abstract:Objective: To reveal the biomechanical remodeling of the aorta and the relationship between the remodeling and hyperglycemia and hypertension in strepozotocin-induced diabetic rats. Methods: The animal model of diabetes with and without hypertension were made on SHR (SHRDM group) and SD(SDDM group) rats respectively by injection of streptozotocin to study the compliance and elastic modulus of their abdominal aorta(AA)in vivo. Results: The compliance of AA decreased from the time of four weeks of diabetes. From the fourth week Ep, Er and Einc of AA began to increase and the increase was enhanced with the progression of disease in SHRDM group and the eighth week in SDDM group. The increase of Ep, Er and Einc in SHRDM group was greater that in SDDM. Conclusionst Compliance was the first to change among the mechanical parameters and can be taken as a sensitive index to evaluate vascular function. Both hyperglycemia and hypertension could increase Ep, and the effect of the former was greater.
2000, 15(1):33-39. DOI: 10.3871/j.1004-7220.2000.1.39.
Abstract:In this study, we examined the effect of the SOA- plate on strain and displacement in the proximal, femur, using 9 fresh cadaver femora instrumented with six strain gauges along the medial and lateral conices. Before and after experimentally created two-part and four-part fractures. Strain patterns and screw motion were compared. With previously obtained values for a sliding hip screw and the Richards screw device, the biomechanical characteristics of the three devices were loaded to 1800N. Experimental results showed, thehe other inter fixation device in the treatment of unstable intertrochanteric fractures (P<0.01).
2000, 15(1):40-43. DOI: 10.3871/j.1004-7220.2000.01.43.
Abstract:To determine the optimal pressures of segmental pressure regulated bandage in the treatment of chronic venous ulcers. Methods: Taking 25mmHg as standard of leg venous hypertension, by means of triple integral, the optimal pressures against venous hypertension were worked out and four layer bandage was designed in the purpose of sustained pressure regulated compression for the healing of venous ulcers. Results f Our optimal pressure data matched nearly to those reported by Stemmer. Preliminary clinical application of four layer bandage was encouraging. Conclusion: Segmental four layer bandage is the optimal non-surgical alternative in the healing of venous ulcers.
2000, 15(1):44-48. DOI: 10.3871/j.1004-7220.2000.01.48.
Abstract:To prove whether or not the fissile spiral type artificial femoral head replacement conforms to biomechanics principles. Methods f Comparative experimental stress analysis was performed on nine fresh cadaver femors which were replaced by three different kinds of artificial femoral head. Results' The fissile spiral type femoral head has a good biomechanical characteristics on stress distribution, stress of inferface, stress shielding rate and initial micro-movement. Conclusion: The femoral head prosthesis of fissile spiral type has a reasonable stress distribution, strong fixation and high stability than the other types in comparison.
2000, 15(1):49-54. DOI: 10.3871/j.1004-7220.2000.01.54.
Abstract:To verify the biomechanic performance of auto-compress locking nail(ALN) in femoral shaft fracture therapy, to provide reliable basis for clinical use. Methods' 9 fresh cadaveric femurs were used,the biomechanic properties of compression,bending and torsion were analysed using electric measuring apparatus after fixation of fracture. Resultst @ALN was similar to GK nail in strength, stiffness and stability(p>0.05); @The stress shielding rate of ALN was significantly smaller than that of GK nail; @ALN had reasonable mechanic distribution, low stress shielding rate and fixation stability, also was easy to operate with rapid rehabilitation. Conclusion: ALN not only have the same properties of anti-bending, anti-shearing,anti-torsion and anti-rotation as GK nails but also have auto-compress elastic fixation. In clinic, rigid fixation(interlocking intramedullary nail) has no enough stress conduction in fracture region, elastic fixation(cloverleaf type intramedullary nail)can not effective ly control bending, shearing, torsion and rotation stress in fracture region, ALN have successfully resolved the contradiction. It is one kind of new interfixation instrument with good performance.
2000, 15(1):55-57. DOI: 10.3871/j.1004-7220.2000.01.57.
Abstract:On the basis of the study of cadavers with the technigue of CT and DIP in this project, 50 young females were undergone investigations through scanning, image analysis, examination and statistics. The inertial data of the Chinese female young bodies including the length, volume, mass and density of the segments of the body, etc. were obtained. The mass distribution of the Chinese female young bodies was determined. A series of reliable data is then provided for establishing the model with inertial parameters of the Chinese human body.
2000, 15(1):58-62. DOI: 10.3871/j.1004-7220.2000.1.62.
Abstract:To investigate the biomechanical properties of the femur in the femoral head necrosis treated with Shengmai Chenggu capsule and to evaluate the efficacy of Chinese herb. Methods : Femoral head necrosis in rabbits was induced with glucocorticoid. 20 rabbits were randomly divided into three groups: treated with glucocorticoid, Shengmai Chenggu capsule and normal saline respectively. The strength and rigidity of the femurs in 16 rabbits were measured systematically. Results: The strength and rigidity of the femur in the femoal head necrosis induced by glucocorticoid was significantly decreased, while those in the femoal head necrosis treated with Shengmai Chenggu capsule were markedly higher. Conclusion: Shengmai Chenggu capsule can increase blood supply, improve necrotic bone repairing, restore the biomechanical properties of the femoral head safely and efficiently.
2000, 15(1):63-65. DOI: 10.3871/j.1004-7220.2000.01.65.
Abstract:To study the relationship between hypertension disease and its danger Indexes of hemorheology in zhanjiang city. Methods f Measured 12 item indexes of hemorheology in hypertension patients, then analyze its property of hemorheology and danger index. Results; In male patients, the index of ESR,HCT,b,p,r, FAD, FIB and EPT were higher than those of normal controls(p<0.01). In female patients, the indexes of ESR, K values, FIB,p, FAD, MW, DW get the same results as male patients(p<0.01). Conclusion: The danger indexes of hemorheology of male hypertension patients are different from female hypertension patients in zhanjiang city.