Longitudinal stress-strain relation of human peripheral vessels ex vivo / 中国组织工程研究

BACKGROUND: Due to the difference of species, the data of vessel in human are particularly useful for the clinical practice.OBJECTIVE: To analyze the longitudinal residue strain and the relationship between stress and strain of human limb arteries and veins, and explore the influence of different biomechanical properties on the repairs of limb injury.DESIGN: Observational trials.SETTING: Institute of Orthopaedics, Xijing Hospital of the Fourth Military Medical University of Chinese PLA.PARTICIPANTS: The experiment was carried out in the Xijing Hospital Affiliated to the Fourth Military Medical University of Chinese PLA from September 2005 to September 2006. The specimens were taken from 13 male amputee donors(who treated for accident injury), aged 18 to 30 years. Those tissue samples were used with the approval from the donors and offered by Xijing Hospital Affiliated to the Fourth Military Medical University of Chinese PLA.METHODS: ①Harvest and preservation of samples: The samples were obtained within 2 hours after death. The vessels were calibrated and harvested without any large branch to avoid the influence on the mechanical property of vessel wall,and then token on major vessels of limbs with Methylene Blue. The distance between the points token on vessel was measured by vernier caliper. The token vessels were cut and taken into Kreb's liquid in ice casement, then were kept into freezer (0-5 ℃). ②Longitudinal stretch ratio measurement: The vessels were taken into Kreb's liquid and the distance between the points token on vessel was measured by vernier caliper. The longitudinal residue strain was expressed by longitudinal stretch ratio. Lab temperature was 20-25 ℃, experiment was finished in 2 hours after sampling.③Stretch test: The vessel cut 1.0 cm was set into the instrument with Kreb's liquid for uniaxial tension test. The change length of each vascular specimen with or without the load and each load was measured three times and was averaged, lab temperature was 20-25 ℃, and experiments were finished in 5 hours after sampling. The curve of stress-strain was fitted by the measured data.MAIN OUTCOME MEASURES: Longitudinal stretching ratio, residue strain and stress-strain relationship of normal limb arteries and veins.RESULTS: The longitudinal stretch ratio of each artery decreased along vascular branch from proximal heart part to distal heart part, and that of each vein was contrast; There were significant difference in the longitudinal stretch ratios of major artery compared with those of saphena megna vein and branchiocephalicae vein (P ＜ 0.001). The curve of artery shifting right showed the stiffness of vessels decreased along vascular branch from proximal heart part to distal heart part. That of vein shifting left showed the stiffness of vessels increased along vascular branch.CONCLUSION: With the major artery of human limbs from proximal end to distal end, both the longitudinal residue strain and the vascular stiffness gradually decreases, as for the vein, the condition is contrast. It suggests that the longitudinal biomechanical property should be involved into the consideration of repairing the artery and vein injuries of different sites.

Study of L-arginine-nitric oxide pathway in ischemia-reperfusion injured limbs in rats / 中华创伤杂志(英文版)

<p><b>OBJECTIVE</b>To observe the change of nitric oxide (NO) levels in the blood and the morphological change of the muscles in the limbs of rats during the (IR) injury and after being intervened by L-arginine (L-Arg) and L-nitroarginine (L-NNA).</p><p><b>METHODS</b>Sixty-six male Sprague-Dawley (SD) rats were used an d grouped into the normal controls, the sham injury controls, the IR injury group and the intervention groups (L-Arg group and L-NNA group). After 6 hours of ischemia, followed by reperfusion for 3, 12 or 24 hours, the samples in the IR injury group were obtained. The rats in the intervention groups were given L-Ar g (100 mmol/L) and L-NNA (10 mmol/L), respectively, through the abdominal cavity. Then the anterior tibial muscle in the right limb was obtained for histological examination, the anterior tibial muscle in the left limb for ultrastructure observation and the blood for assay of NO in all the rats. NO was assayed by indirect measurement of NO(2)(-)/NO(3)(-) with Griess method.</p><p><b>RESULTS</b>There was no significant difference of NO between the normal controls and the sham injury controls (P>0.05). But NO significantly decreased in the IR injury group (P<0.01), and further decreased with reperfusion (P<0.01) and reached the lowest point at 12 hours after reperfusion. The level of NO in the L-Arg group was significantly higher than that in the IR injury group ( P<0.01), but was not significantly different from that in the controls (P>0.05). In the L-NNA group, NO decreased to the undetectable level (P<0.01). Histological examination and ultrastructure observation showed the muscles were normal in the control groups. After 6 hours of ischemia, the skeletal muscles displayed injuries, and they were most severely injure d after 12 hours of reperfusion. In the L-Arg group, the skeletal muscles were less injured, while in the L-NNA group, the injury was similar to that in the I R injury group.</p><p><b>CONCLUSIONS</b>When the limbs of the rats sustain IR, NO in the blood decreases. Meanwhile, the muscles in the limbs are injured. When L-Arg is given, NO in the blood is restored and the muscles are protected. When L-NNA completely inhibits NO, no protection of the muscles is shown.</p>

Treatment of limb arterial injuries caused by traffic accidents / 中华创伤杂志(英文版)

<p><b>OBJECTIVE</b>To analyze the features, diagnosis and treatment of limb arterial injuries caused by traffic accidents.</p><p><b>METHODS</b>A total of 43 patients with limb arterial injury admitted in our department over the past 30 years (about 50% of them happened during the last 10 years) were analyzed retrospectively in this article. The popliteal, femoral and brachial arteries were mainly involved, accounting for 43.2%, 20.5% and 20.5% respectively of all the involvements. There were 35 cases of open injury and 9 of close injury. The involved vessels were transected in 43.2% of the cases and contused in 40.9%. All the patients had various complications, such as fractures, dislocations and severe soft tissue injuries. The injured vessels were repaired by means of end-to-end anastomosis in 10 cases, autogenous vein graft in 23 cases and intraluminal hydraulic dilatation in 4 cases.</p><p><b>RESULTS</b>Successful limb salvage was achieved in 34 cases initially, whereas 10 amputations were carried out due to injuries to popliteal arteries in 7, femoral arteries in 2 and humeral artery in 1 and severe soft tissue damages in 9 cases. Twenty-nine patients were followed up for 1-156 months, with the average of 48.8 months. There was good circulation in 22 cases and certain ischemia in 5 cases. Two amputations were carried out in the late stage because of popliteal artery thrombosis after repair in 2 cases. There was no death in this series.</p><p><b>CONCLUSIONS</b>The limb arterial injuries caused by traffic accidents are severe and complicated. It is proposed that particular attentions should be paid to the features in diagnosis and treatment for this type of injury and special efforts should be made for both life saving and limb salvage.</p>

Compliance variation following the change of longitudinal stretch ratio. A study on femoral artery and vein in a rabbit model / 生物医学工程学杂志

This study was aimed to establish a rabbit model of bridging artery defect with autogenous vein under equal arterial and venous compliances by selecting an appropriate anastomosing tension based on assessing the influence of vessel's longitudinal strain on compliance. The exponential form P = M1 x [eM2(v-v0)-1] was employed to fit the blood pressure-unit volume curves under different stretch ratios(lambda) obtained from real curves on 13 femoral arteries and 12 veins whose uniaxial loading tests at longitudinal directions had been performed, then the quantic M = a1 lambda 5 + a2 lambda 4 + a3 lambda 3 + a lambda 2 + a5 lambda + a6 was done to fit M-lambda data. Results showed the differential form dv/dp = 1/(M1 x M2 + 11.78 M2) derived from P = M1 x [eM2(v-v0)-1], and lambda reflected the relationship between compliance and stretch ratio (or longitudinal tension) under average artery pressure 11.78 KPa well. It was found that under longitudinal tension 1.19 g, the arterial and venous compliances were equal(0.031 microliter/KPa) while the respective stretch ratios were 1.32 and 1.67.

Expression of adenoviral mediated NT- 3 genes in Schwann cells of sciatic ne rve in the rats / 中华骨科杂志

Objective To investigate the expression of neurotrophin- 3 (NT- 3) gene in Schwann cells (SCs) of rat sciatic nerve introduced by adenovir al vector in vivo. Methods Recombinant adenoviral vector for NT- 3 was propagat ed in 293 packaging cells and was titered by tissue culture infections dose 50 ( TCID50) method. Ad- NT- 3 was injected intraneurally into the rat sciatic nerv e following axotomy of the sciatic nerve which was repaired after the immediate injury. Immunohistochemical staining was employed to determine the expression of NT- 3 in SCs in rat sciatic nerve, and the expressive intensity difference was measured with LEICA M550 imagine analysis system on the tissue slides. Results Two days after injection of NT- 3 into the rat nerve, positive stain in the SCs were apparent in the vicinity of anastomosis. There was significant increase of the amount of NT- 3 expression 7 days following injection of Ad- NT- 3 (vs. 2 days group P0.05). Compared with the 2 days group, the 14 and 28 days groups still maintained a relatively high leve l of NT- 3 (P

Longitudinal stress and strain of normal human vascular system of the extremities, and the blood vessels following venous repair / 中华骨科杂志

Objective To investigate the longitudinal residue strain and stress-strain relation of normal human vascular system of the extremities and the relation between the different defect length and the option of repair, as well as a comparison of the different selection of the methods of repair judged from the longitudinal biomechanical effect. Methods A mechanical analysis including stretch experiment and longitudinal stretch ratio measurement were undertaken to evaluated the longitudinal residue strain and stress-strain relation of arteries and veins of the extremities in human. The results of different methods for repair of the defect of the same kind of vessels were compared with Student-t test. The length precinct to repair arterial injuries between end-to-end anastomoses and vein graft through 95％ distribution region was evaluated. Results The longitudinal stretch ratio of arterial system of the extremities decreased from the proximal to the distal ends of the vascular branches and the stress-strain relation curve of artery turned gradually to the right side, while that of veinous system exhibited a contrary picture. There was significant difference among the stretch ratio of artery and those of branchiocephalic vein or great saphenous vein (P

Hemodynamics of Human Arterial Injuries Following Repair With End to End Anastomosis / 中华骨科杂志

0.05). Conclusion\ The hemodynamic factors and the mean vascular wall shear stress were useful parameters for the evaluation of the effect of vascular repair. Periodical and continuous observations are helpful for predicting the outcome of vascular anastomosis repair.

SURGICAL TREATMENT OF INJECTION INJURY OF PERIPHERAL NERVE:A REPORT OF 62 CASES / 解放军医学杂志

Surgical treatment of postinjection injury of peripheral nerve in 62 patients are reported, 50 patients were followed-up for 3 years in average. Neurolysis is an effective method in the treatment of such injuries with 64 percent of excellent and good result observed in this series. The results of operation were related to the degree of severity of nerve injury, timing of operation, and extent of adhesion of the injured nerve. The result of early operation is better than late operation.