Abstract An animal experiment had been conducted for the purpose to find out the possibility of application of instantaneous sustained limited expansion (ISLE). A total of 54 skin defects in 9 pigs were obtained and were divided into two groups. One group of the pigs were subjected to instantaneous sustained limited expansion, the others, as the control group, just received the tension suture. At the same time the blood supply of the skin was measured by laser doppler flowmeter (LDF). It was showed that microcirculatory perfusion of the ISLE group was considerably better than that of the control. Inaddition, the correlation between the blood flow of the skin and the expanding pressure, as well as the pathologic changes of the skin were discussed.
Thiry wistar rats were used and divided in 2 groups. A segment of 6mm was excised in the sciatic nerve which were then bridged with chitin and skelal muscle. at 4,8,12 weeks after operation, In the chitin group a satisfactory regeneration of nerve fibers was evident with electrophysiologic and histologic examinations, and HRP retrogade labelling evaluation. The possible mechanism of enhancing nerve regeneration of chitin was also discussed.
Abstract In order to find a new method to repair large bone defect, the free periosteum autograft was investigated in experiment, and then the method was used clinically. In the experiment, a 6mm×18mm×5mm bone defect was made at upper end of both tibiae of 42 rabbites. The periosteum of each rabbit was cut into 1mm cubes, and implanted randomly into the tbial bone defect on one side and the other side was used as control. After 2, 4, 8 weeks, the bone defects of each group were examined for bone formation by roentgenography, radionuclide and histology. The results showed that the defects treated by free periosteum autografts healed twice as fast as the controls (its natural healing). The reason probably was that the periosteum provided with many osteogenic cells. On thebasis of these results, 21 cases of bone defects (the largest was 10.5cm×4cm×4cm, the smallest was 2cm×2cm×2cm) including 17 cases of benign bone tumor and4 cases of chronic osteomyelitis, were treated by free periosteum autografts. The defects were all healed, and the function of the joints was restored.
Abstract In order to study the influence of chitosan on bone infection, 27 New-Zealand rabbits were randomly divided into 3 groups. According to the Norden technique, the model of osteomyelitis of the tuberosity of tibia was produced experimentally by injection of staphylococcus aureus.Immediately following injection of the staphylococci, the chitosan gel, acetic acid solution and sterile distilled water were injected into the bones in the 3 groups respectively. The latter two groups were served as control. The severity of the infection was evaluated by clinical symptoms and signs, radiographicdata as well as the bone culture and bacterial counts. Compared the results from chitosan with the other two controls, it was found that the local injection ofchitosan could not reduce the incidence of bone infection, however, it could provide actual improvement when other data were concerned. The effects of chitosangel might be attributed to its bacteriostatic and immunological activity as well as its slow degradation in the body.
To observe the changes of intestinal bacteriology in acute necrotizing pancreatitis (ANP). Dog ANP model was induced by injection of sodium taurocholate with trypin into the pancreatic duct. All dogs were sacrificed on the seventh postoperative day, mucosal and luminal microflora of intestine were analyzed quantitatively. The blood and organs were collected for culture. The results showed that population levels of E.coli in the intestinal mucosa and the content in cecum of the ANP dogs showed much higher level than those of the controls (Ｐ＜0.01 or Ｐ＜0.05), while bifidobacterium and lactobacillus were decreased significantly (Ｐ＜0.01), resulting in reversal of bifidobacterium/E.coli ratio. Blood levels of endotoxin were 1-2 times higher in ANP group as compare with the controls. The positive rate of blood and organs were 100% in ANP dogs. E.coli were the major bacteria cultured. The results indicated that microecological disturbance could take place after the onset of ANP, which may take an important role on pancreatic infection complicating ANP.
Motor endplate is the structure connected between the nerve terminal and muscle fibre and plays a very important role in conducting nerve impulses to the target, therefore, systemical study of the sequential changes of the motor end-plate upon denervation is quite important.Ninety New Zealand rabbits were divided into nine groups from two weeks to nine months after denervation. Acetycholinesterase(AchE) was analyzed quantitatively to study the sequential changes of the motorendplates of tibialis anterior muscle. The results showed that there was no significant reduction of AchE at theend if one month after denervation, whereas a sharp reduction of AchE afterwards. AchE could not be stained after five month denervation.
In order to investigate the possibility of porous hydroxyapatite ceramics (HAC) in the repair of skull bone defect, twenty-four rabbits were used. The bone defect model was created by operation to obtain a defect in parietal bone in a size of 1 cm x 1 cm. Filled the defect with HAC and methyl-methacrylate-syrene copolymer (MMAS) to fill the defect as control. At 1st, 2nd and 3rd months after operation, behavior of the rabbits was observed and then these animals were sacrificed and specimens were examined under microscope. Results showed as follows: after operation, behavior of all animals were normal. By histological examination, it was found that in HAC group, there were granulation tissue, fibrous tissue and newly formed vessels grew into the pores and the osteoblasts formed osseous trabeculae. There was no inflammatory cell infiltration. In the MMAS grafted asea, there was formation of fibrous membrane. It suggested that HAC might be a good material for bone substitute in repair of skull bone defect.
This experiment consisted of removing a segment of femoral artery measuring 3cm from Japanese white rabbits. The arterial segments were divided into 3 groups and grafted as homograft at different periods of time. The segments in group 1 were grafted immediatly after their removals, those in the group 2 and group 3 were stored at -30 and -196 degrees centigrade before grafting, respectively. The results from gross and histological examinations, it was noted that following deep freezing the long term patency rate after grafting of the arterial homografts was superior to those not undergoing deep freezing. Those stored at 30 degrees centigrade for 12 weeks had the lowest patency rate.
Hyaluronic acid (HA) is an extracellular matrix having a high molecular weight. This study is to investigate (1) whether the ultrapure HA had effect on the healing of full thickness skin wounds in animals, and (2) the relation between the effect of HA and the size of the molecular weight of HA. The ultrapure HA with different molecular weights and HA with intermediate molecular weight were applied topically to the wounds from removal of full thickness of skin and topical application of normal saline was used as control. At 21st, day after the topical application, the tensile strength was reduced in wounds of groups of HA with high and intermediate molecular weights, but not in the group of low molecular weight. Using laser-Doppler scanning of the dynamic changes of the wound perfusion, in the 3rd day the blood supply to the wound was reduced in HA groups of high and intermediate molecular weights, but at the 7th day, the blood supply of all wounds in the two groups was increased. The study revealed that HA with different molecular weights had different actions on the contraction of wounds, the angiogenesis of the granulation tissues and the healing strength of the wounds. It was indicated that hyaluronan could be used for wound treatment or as a carrier, but its accurate composition must be carefully noted.
Application of the island flap on the back of rabbit as a model, the central vessel and its anterior edge vein was perserved. We explored the features of the blood supply and the difference in the dependence of the recipient bed of pure venous flap, arteriolised venous flap and conventional flap. The result showed that the conventional flap and arteriloized venous flap could survive, but the pure venous flap could not. It was suggested that the pure venous flap was in an impending necrotic condition, therefore,the blood circulation of recipient bed and the rate of revascularization between the recipient bed and the flap seemed to play an important role in the survival of the flap.
