A mechanical study on the bones of 29 rabbits following implantation of carbontendon was carried out. The rabbits were divided into seven groups according to the observation time (2,4,6,8,12,20 and 30 weeks after operation). A bundle of artificial tendon composed of 7,000 carbon fibers was passedthrough a tunnel in the tibia, and both ends of the artificial tendon were ligated to the muscle fibers. The mechanical strength and histological structure of the carbonbone junction and their relationship were studied in each group. Carbon fiberwas split and degradated in six to eight weeks after operation. The tensile strength of carbontendon in the soft tissue was decreased from 82±4.6N in the second week to 27±5.31N and6.3±1.81N in the sixth and eighth week respectively. The tensile strength of carbontendon increased from 3.01±1.2N to 6.1±2.01N at the carbon -tendon-bone junction in the bone. The tensile strength of carbon-tendon was unsatisfactory for implantation into bone. The carbon-tendon was split and degradated and the tensile strength was not b enough to cope with the early functional exercises.
The influence on the wrist stability following ulnar head resection (Darrach s procedure)was studied. A series of X-ray films and arthrography of the wrist joint were taken before and after ulnar head re- section. The results showed that after ulnar head resection the radial deviation increased 3 degree(Plt;0.01). and the ulnar deviation 11.92 degree (Plt;0.001). The position of the lunate remained unchanged. Arthrography of the wrist joint demonstrated that 11 specimens had injury of the triangular fibrocartilage.The stability of the wrist joint would no doubt be certainly affected following the ulnar head resction.
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.
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 ...
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.
ObjectiveTo observe the ability of osteogenesis in vivo using the injected absorbable polyamine acid/calcium sulfate (PAA/CS) composites and assess their ability to repair bone defects.
MethodWe selected 48 New Zealand white rabbits, and half of them were male with a weight between 2.0 and 2.5 kg. Bone defect models were made at the rabbit femoral condyle using electric drill, and the rabbits were divided into two groups. One group accepted implantation of the material at the defect, while nothing was done for the control group. After four, eight, twelve and sixteen weeks, the animals were killed. The line X-ray and hard tissue slices histological examination (HE, MASSON staining) were observed to assess the situation of degradation, absorption and bone formation of the material.
ResultsFour weeks after operation, bone defect of the experimental group had no obvious callus growth on X-ray imaging. Histology showed that the material began to degrade and new immature trabecular bone grew. The bone defect of the experimental group had a small amount of callus growth on X-ray imaging after eight weeks. And histology showed that the material continued to degrade and new immature trabecular bone grew continually. There was an obvious callus growth after twelve weeks, and the bone defect area had smaller residual low-density shadow on X-ray imaging. Histology showed that most of the materials degraded and parts of woven bone grew into lamellar bone. After sixteen weeks, the composites were absorbed completely, replaced by new bone tissues, and the new bone was gradually changed from woven bone into mature plate of bone. There was no significant change in bone defect in the control group within twelve weeks, and part of bone defect hole became smaller, and partial edge repair could be detected.
ConclusionsThe PAA/CS composites can be completely degraded and absorbed, with a certain activity of bone formation, expected to be used as bone repair materials.
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.
Allogeneic mouse model of peritoneal heart transplant is a microscopic surgery on small animal with complex techniques. For a beginner, a learning curve of this surgical technique has to be experienced. The learning curve contains three stages:(1) to be familiar with the local anatomy of either donor or recipient mouse; (2) to be capable of collecting donor heart and well preparing the major peritoneal vessels of recipient; (3) to be skillful in the anastomosis of major vessels. The bottleneck of the learning curve is the valid skill of vascular anastomosis. The stepwise essentials are to "understand, be familiar, be accurate, and be quick" in the learning curve.
【Abstract】Objective To investigate the inhibitory effects of flavonoids quercetin on the occurrence and proliferation of experimental mammary carcinoma. Methods DMBA induced mammary carcinoma was produced in rats. Seventy-nine female Sprague-Dawly rats were divided randomly into four groups: DMBA, DMBA with TAM, DMBA with quercetin and control. Chemicals had been administered to group A, group B, group C and group D respectively for 28 weeks. Samples of breasts were collected for light microscope observation and electromicroscope observation. Their expressions of proliferating cell nuclear antigen (PCNA) and the protein product of H-ras were examined by immunohistochemical staining. Results ①Mammary carcinoma incidence of group A(76.2%) was significantly higher than that of group B(40.9%), group C(45.5%) and group D(0%),P＜0.05, and there was no significant difference between group B and group C (P＞0.05), which indicated that quercetin could inhibit the occurrence of mammary carcinoma. ②Mean mammary tumor diameter of group A (2.37cm) was significantly larger than that of group B(1.82cm) and group C(1.71cm), P＜0.05, and there was no significant difference between group B and group C (P＞0.05), which indicated that quercetin could inhibit the growth of experimental mammary carcinoma. ③Immunohistochemical staining of PCNA showed significant difference between group A and group B, group A and group C (P＜0.05), with no significant difference between group B and group C (P＞0.05), which indicated that quercetin could inhibit the proliferation rate of tumor cells. ④Significant difference between group A and group B, group A and group C (P＜0.05), and no significant difference between group B and group C (P＞0.05), were noticed with immunohistochemical staining of H-ras protein product, which indicated that quercetin could inhibit the activity of Hras protein. Conclusion Quercetin could reduce the mammary carcinoma incidence and its degree of growth, and it may be related with its inhibitory effect on the activity of Hras and the proliferation of tumor cell.
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.
