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.
Local hypothermia as a preventive method to reperfusion injury of skeletal muscles was studied. Sixteen Japanese rabbits were divided into four groups at random. Before the tourniquet was inflated, a cold gel pack was applied to the right hind leg of each rabbit for 15 minutes to produce local hypothermic condition, without application of tourniquet the left hind limb was under local hypothermic condition as a control. The duration of tourniquet ischemia was 4 hours, and then reperfusion for one and two hours in the A and B groups respectively; in the C and D groups the duration of ischemia was 5 hours, and reperfusion for one and two hours, respectively. The muscle temperature averaged 16.6 degrees C with a needle thermocouple in the hind limb under local hypothermia. The serum K+, LA, SOD, LPO were determined from bilateral femoral veins, and electron and light microscopic studies of sural muscles were done in the post-reperfusion period. It was found that the K+, LA, LPO were lower than that of the control groups (P lt; 0.01), but SOD was higher than that of the control group (P lt; 0.01). Electron and light microscopic studies showed sight but reversible damage of muscular structure with the possibility of in the hypothermic groups cell regeneration. Basing on this experimental results, this method was applied in 45 cases reparative and reconstructive surgery of limbs. The duration of application of tourniquet averaged 2 hours and 57 minutes, the longest being 4 hours and 31 minutes, when the muscle temperature had reduced to 22.4 degrees C. There were no postoperative complications associated with this technique. Local hypothermia appeared to be a safe and effective method of decreasing the reperfusion damage after ischemia.
Abstract A new kind of soft tissue expander with exteriorized injection valve was reported. Two types of expanders were designed: one with single cyst, single tube and single chamber, and the other with single cyst, single tube but double chambers, i.e, an additional drainage chamber. The drainage orifice could be controlled by a valve. An animal experiment had been conducted, and the outcome suggested that the new expander could provide rapid expansion of the soft tissue, sufficient drainage of the expanded area. The bacterial culture showed that among the 42 samples obtained from the expanded cyst, only 3 were positive. (2 of bacteria and 1 of fungus), suggesting comparatively low cyst infection.
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.
It was reported that the systemic use of phenytoin could promote healing of fracture. In order to observe the effect of local application of phenytoin in the healing of fracture, the experiment was performed. Seventy-two rabbits were divided into three groups. Fractures were created on both radius of all rabbits. Group 1, intraperitoneal injection of phenytoin with a dosage of 50 mg/kg per day; Group 2, local use of phenytoin with a dosage of 40 mg/kg was injected in the fracture site every seventy-two hours, and Group 3, injection mormal saline of in the control group. Eight rabbits in each group were sacrificed in the 9th, 16th and 30th days after operation respectively. By X-ray excuiualtion, the healing of fracture was observed. Dry and wet weights of the callus were determined. After HE and Mallory’s stain, the samples were examined under microscope. Results showed that both local and systemic use of phenytoin promoted healing of fracture. The effects of phenytoin in the two groups were the same and had no significant difference.
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.
A comperative study Of the thickness,the ratio of length to width and the division time of the pediele between the randomized defatted skin flap and the randomized conventional skin flap wasundertaken in 12 pigs,weighing 25-30 kg.Two tpe of defatted edicled skin flape were made,inwhich,one preserved a thickness of 2-3mm adipose tissue and the Other one third of the superficialfascial beneath the subeutaneous vascular network.The resuIts indicated that after division of thepedicles on the ...
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 function of epidermal growth factor (EGF), the following experiments were performed. Thirty white rats were chosen and divided into 3 groups. In the back of each rat, two 2 cm x 2 cm wounds were made bilaterally, the skin and subcutaneous tissue was removed. EGF were used in one of the two wounds randomly, while those without EGF usage in control. After 1, 2 and 3 weeks, the rats were sacrificed. The area of the wounds was measured, and the healing time of each wound was recorded. The results showed that the healing time of EGF group was 14.6 days while that of control group was 18.5 days (P lt; 0.01). Furthermore, the DNA, protein and hydroxyproline contents of EGF group were higher than those of the control group (P lt; 0.01). It was suggested the EGF could accelerate wound healing and shorten the healing time.