OBJECTIVE: To explore a new method of preparing the composite of DL-polylactic acid (PDLLA), hydroxyapatite(HA), decalcium bone matrix (DBM), and to observe the degradation characteristics of PDLLA/HA/DBM in vitro. METHODS: An emulsion blend method was developed to prepare the composite of PDLLA/HA/DBM based on the weight rate of PDLLA:HA:DBM = 1.5-2:1-1.5:1. The characteristics of the particles was observed by scanning electron microscope. In vitro, PDLLA/HA/DBM and PDLLA were put into PBS(pH7.4) respectively; the pH value, weight and biomechanics of them were determined during the degradation. RESULTS: Without heating, the emulsion blend method could be developed to prepare PDLLA/HA/DBM. Scanning electron microscope showed that the gap diameter in the compound material was 100 to 400 microns, and the porosity was 71.3%; During degradation, the pH value of PDLLA decreased little within 2 weeks, then decreased obviously and decreased to 4.0 at the end of the 4th week; while the pH value of PDLLA/HA/DBM kept quite steady and was 6.4 at the end of the 12th week. The weight of PDLLA decreased little within 4 weeks, then decreased obviously and remained 50% of its prime weight at the end of the 12th week; while the weight of PDLLA/HA/DBM decreased little within 5 weeks, then decreased obviously and remained 60% of the prime at the end of the 12th week. The prime biomechanical strength was 1.33 MPa in PDLLA and 1.71 MPa in PDLLA/HA/DBM. There was significant difference between them (P lt; 0.05). The strength of PDLLA decreased little within 3 weeks, then decrease obviously and was 0.11 MPa at the end of the 12th week; the strength of PDLLA/HA/DBM decreased little within 4 weeks, then decrease obviously and was 0.21 MPa at the end of the 12th week. CONCLUSION: The emulsion blend method is a new method to prepare bone repair materials. As a new bone repair material, PDLLA/HA/DBM is suitable for bone tissue engineering for its good characteristics of porosity and degeneration.
OBJECTIVE To investigate the adhesive interactions of cells with materials and the effects of material properties on cell adhesion in tissue engineering. METHODS By looking up the recent literatures dealt with adhesive interactions of cells with materials and reviewing previous work on the adhesion of tissue-derived cells to materials. RESULTS The adhesion characteristics of cells to materials not only depend on the nature of materials, including bulk and surface properties, surface modification, surface morphology, net charge, porosity and degradation rate, but also on the expression of cell surface molecules and their interaction with the material. CONCLUSION The quantitative measure and biophysical mechanisms of cell adhesion to materials might be very important in tissue engineering.
OBJECTIVE The purpose of this study was to find the best material for valvular wrapping operation of deep vein of lower limb and to study the diagnostic value of colored Ultrasonic-Doppler for valvular incompetency of the deep vein and the function of the popliteal valve. METHODS Strips of autogenous saphenous vein, autogenous fascia lata and pieces of polytetrafluroethylene artificial vessel were used respectively as the wrapping material for narrowing the valve in 30 dogs. The results of three different wrapping material were obtained by colored Ultrasonic-Doppler and transpopliteal venography in 78 patients. The hemokinetics of the popliteal valve was examined in 20 normal persons. RESULTS In the saphenous vein and fascia lata groups, diffuse fibrosis and marked narrowing of the femoral vein were found, while in the group of artificial vein graft, the graft was intact without prominent fibrosis and narrowing of the vein. In comparing with the result of venography, the accuracy of diagnosis by colored Ultrasonic-Doppler was 91.86%. The femoral and popliteal venous valves closed at the same time when holding the breath, but the popliteal venous valve opened more widely than the femoral venous valve when the calf muscles of the leg contracted. CONCLUSION It was suggested that the graft was the best material for valvular wrapping operation, and colored Ultrasonic-Doppler was an important and non-invasive method for the diagnosis of incompetency of deep vein. The popliteal venous valve was the important barrier for protection of the function of deep vein.
Objective To summarize the experience of preparation and administration of medical materials for the daytime-sickroom during the treatment of patients who were injured during Wenchuan earthquake in order to supply management experience for future emergency situations. Methods Data concerning the preparation and administration of medical materials and medical treatment for the daytime-sickroom were collected systematically. Results The high level of activity and order during the rescue provided quality care to patients injured in the earthquake. All 224 patients were treated effectively from May 12-29.Conclusion The daytime-sickroom acts as a combination sickroom, which allowed flexibility. The daytime-sickroom can manage medical materials and succesfully insure the treatement of patients when emergent events happen.
During the medical rescue after Wenchuan earthquake, the Department of Appliances and Materials of West China Hospital took prompt action to ensure the regular operation of hospital devices and facilities. Meanwhile, owing to its specialized superiority of material and appliance purchase as well as the optimized processes for material and appliance supply, the hospital ensured the effective supply of disaster relief materials and efficiently managed the consumption of donated materials. From May 12 to 30, a total of 2 200 000 pieces of medical materials (total value RMB 3 770 000 Yuan) and 220 sets of medical appliance (total value RMB 9 000 000 Yuan) were purchased as part of the immediate medical rescue response to the earthquake.
Objective To review the clinical operation methods of abdominal incisional hernia. Methods Classification, operation method and fellow-up of 78 patients with abdominal incisional hernia were retrospectively analyzed. Results The average time of fellow-up was 26 months. Nineteen cases were repaired with simple suture with 3 cases (15.8%) recurrence, 57 cases were repaired with man-made material with 2 case （3.4%） recurrence. Conclusions Individual operation method should be chosen according to body condition, classification of the size of abdominal loss and abdominal hypertension. It is an effective method to repair the hernia of abdominal incision with man-made material.
To solve the problems of small one-time ablation range and easy charring of the tissue around the electrode associated with the tumor radiofrequency ablation needle, based on the multiphysical field coupling analysis software COMSOL, the effects of needle material, the number of sub needles and the bending angle of sub needles on the ablation effect of radiofrequency ablation electrode needle were studied. The results show that compared with titanium alloy and stainless steel, nickel titanium alloy has better radiofrequency energy transmission efficiency and it is the best material for electrode needle. The number of sub needles has a great influence on the average necrosis depth and the maximum necrosis diameter. Under the same conditions, the more the number of sub needles, the larger the volume of coagulation necrosis area. The bending angle of the needle has a great effect on the maximum diameter of the coagulated necrotic area, but has little effect on the average necrotic depth. Under the same other conditions, the coagulation necrosis area formed by ablation increased with the increase of the bending angle of the sub needle. For the three needles with bending angles of 60 °, 90 ° and 120 ° analyzed in this paper, the one with bending angle of 120 ° can obtain the largest coagulation necrosis area. In general, the design of nickel titanium alloy with 120 ° bending 8-pin is the optimal. The average depth of radiofrequency ablation necrosis area is 32.40 mm, and the maximum necrosis diameter is 52.65 mm. The above optimized design parameters can provide guidance for the structure and material design of tumor radiofrequency ablation needle.