Therapeutic effect of vacuum-assisted closure technology on infected explosion wound of pig / 中华烧伤杂志

<p><b>OBJECTIVE</b>To investigate the effect of vacuum-assisted closure (V. A. C.) technology in the treatment of infected wound of skin and soft tissue as a result of explosion injury in pig.</p><p><b>METHODS</b>Sixteen explosion wounds were established by electric detonators on the shoulders and hips on both sides of 4 small white domestic pigs ,and they were divided into A group [(without treatment and infection occurred on 1-2 post burn day (PBD), then treated with vaseline gauze on 3 (PBD)], and B group (with the same treatment as in A group, except for treatment of vacuum assisted closure (V. A. C) with pressure of - 15 kPa after 3 PBD). The data of wound depth, wound area, wound healing time were collected and analyzed at 3 PAD and 1, 3, 6, 9, 14, 19, 24 days after treatment. Specimens from wounds were collected for histopathology observation, including also cell proliferation index, the number of vascular endothelial cells, the activity of myeloperoxidase (MPO) and the number of bacteria.</p><p><b>RESULTS</b>Compared with those in A group on land 3 days after treatment, wound area, wound depth were not enlarged or deepened in B group, while the number of inflammatory cells, vascular endothelial cells, proliferative cells were increased, the activity of MPO was enhanced and the number of bacteria was decreased. There were obvious differences between two groups in following indices: wound area ,wound depth, the number of vascular endothelial cells and bacteria during 1 to 19 days after treatment (P < 0.01)), the number of cell proliferation from 1 - 9 days after treatment (P < 0.01)), and the activity of MPO on 3, 6 days after treatment (P < 0. 01). The wound healing time was (32.8 +/- 1.6) d in A group, which was longer than that in B group (25.8 +/- 1.0 d, P < 0.01).</p><p><b>CONCLUSION</b>Compared with conventional dressing change, V. A. C can decrease bacteria load, lessen secondary necrosis, prompt the inflammatory response, accelerate the formation of granulation tissue, shorten wound healing time in infectious wound of porcine skin and soft tissue resulted from explosion injury.</p>

The influence of vacuum-assisted drainage on the growth of capillaries in the wound produced by explosion in pig / 中华烧伤杂志

<p><b>OBJECTIVE</b>To investigate the influence of vacuum-assisted closure (VAC) technique on the growth of capillaries in the wound of the pig produced by explosion.</p><p><b>METHODS</b>Four small white pigs were inflicted with 16 explosion wounds [(7.3 +/- 1.0) cm2 in area] on both sides of the buttocks, shoulders and hips by detonation of a specific type of explosive, and the wounds were randomly divided into 2 groups, i. e, control (C, with conventional treatment from 2 post-injury day (PID) on and treatment (T, with VAC treatment after debridement from 2 PID on) groups, with 8 wounds in each group. Wound tissues of 2mm x 2mm x 2mm in size were harvested for pathological examination before treatment and on 1 and 3 post-treatment day (PTU). The differentiation of adventitial cells were examined with light microscope, and the pixel value of desmin positive particles and the luminal area of newly formed capillaries were assessed with Image C software.</p><p><b>RESULTS</b>Most of vessels in the wound of both groups were in elliptic shape when observed in longitudinal section. In C group, few newly formed capillaries vessels with lack of pericytes were observed before treatment and on 1, 3 PTD, then the number began to increase on 6 PTD. In T group, the number of newly formed capillaries with pericytes was increased on 1 PTD, and it continued to increase thereafter. The pixel values of desmin positive particles in C group on 1, 3, and 6 PTD were (91 +/- 54), (199 +/- 85), and (1552 +/- 298), respectively, which were obviously higher than those in T group [(2569 +/- 330), (3984 +/- 377), (9611 +/- 960), P < 0.01]. The area of vessel lumen in C group was (59 +/- 36), (250 +/- 70), and (938 +/- 287) microm2, respectively on 1, 3, and 6 PTD, which was also smaller than those in T group [(818 +/- 234), (4518 +/- 1080), and (9058 +/- 1656) microm2, P < 0.01].</p><p><b>CONCLUSION</b>Compared with conventional therapy, VAC can not only accelerate the formation of new capillaries, but also enhance the differentiation of pericytes and the process of enwrapping them around the vessels, and increase the luminal area of newly formed capillaries.</p>

The changes in blood flow in sciatic nerve after electrical injury in rabbit / 中华烧伤杂志

<p><b>OBJECTIVE</b>To study the changes in sciatic nerve blood flow and the expression of collagen type I after electric injury of rabbit nerve with different voltages.</p><p><b>METHODS</b>Thirty-six healty rabbits were randomized into 3 groups before receiving injury with electricity in voltages, i.e. 50 v, 75 v, and 100 v groups. The changes in blood flow of sciatic nerve were observed with Laser Doppler Flowmeter immediately after injury and 1, 4, 8 weeks after injury. The changes in the expression of collagen type I was observed by immunohistochemical method, and the positive expression rate was calculated.</p><p><b>RESULTS</b>The sciatic nerve blood flow increased in all groups immediately after electric injury. In the 75 v and 100v groups, the nerve blood flow [(53 +/- 3 ), (48 +/- 5) PU] was obviously lower than that of normal value [(62 +/- 4) PU, P < 0.05]. There was little collagen type I deposition in 50 v group, while brown collagenous fibers in epineurium and perineurium were observed in 75 v and 100v groups 4 and 8 weeks after injury. The expression of collagen type I in all groups were obviously higher than that of normal value, and that in 75v and 100 v groups were higher than that in 50 v group at bachl time-point (P < 0.01).</p><p><b>CONCLUSION</b>The restoration of sciatic nerve blood flow is postponed following by the injury with increase of the electrical voltage. The collagen deposition after electrical injury may be one of the reasons for nerve blood flow decrease.</p>

Effect of vacuum assisted closure on collagenase activity in human chronic wound / 中华整形外科杂志

<p><b>OBJECTIVE</b>To study the variations of collagenase activity in exudates of human chronic wound before and after treatment of VAC so as to partly disclose the mechanisms of VAC in promoting chronic wound healing.</p><p><b>METHODS</b>The exudates of acute wounds (postoperative breast cancer) were postoperatively collected at day 1, 2, 3, and in 6 chronic wounds (4 cases of venous ulcer, 2 cases of pressure sore) the exudates were also collected before and 2, 4, 6 days after the treatment with VAC. The type-III collagen degradation from the exudates was checked with zymography timepoint. The types of the collagenase in exudates were evaluated by using doxycycline inhibition.</p><p><b>RESULTS</b>Drainage fluids from acute wound might degrade type-III collagen partly with no changes at day 1, 2, 3. There were high collagenase activities in chronic wound exudates. Exudates from patients before treatment with VAC can degrade type-III collagen completely. But collagenase activities became less and less after VAC. Doxycycline inhibition tests indicated that it can't inhibit the activity of collagenase at 100 micromol/L concentration, until it reached 600 micromol/L.</p><p><b>CONCLUSIONS</b>Collagenase activity is elevated in chronic wounds. VAC may be lower the collagenase activity, prevent collagen from degrading abundantly and promote wound healing. Collagenase is mainly MMP-1 type (fibroblast-type) in chronic wound exudates.</p>

500 cases of external ultrasound-assisted liposuction / 中华整形外科杂志

<p><b>OBJECTIVE</b>To discuss the therapeutic effects and safety of external ultrasound-assisted liposuction and to find out the rules of circumference variation in different body areas after liposuction.</p><p><b>METHODS</b>External ultrasound liposuction was performed on 500 patients (595 sites). We recorded the volume of anesthetic drugs and the aspirated pure fat as well as the body contour variations of every area at one to three months postoperatively. The decreased dimension at different body sites after liposuction were compared and analyzed.</p><p><b>RESULTS</b>The volumes of the anesthetic liquid and the aspirated pure fat were the most in the waist-abdomen and the thigh. After liposuction, the circumstances in different body areas were all decreased to certain degrees. Along with the severity of obesity, changes in the waist-abdomen became more obvious and the decreases of the umbilical circumference, the minimum and the maximum waist circumferences were prone to be less. But when the, minimum waist circumference was over 111 cm, obvious changes occurred in the umbilical. Meanwhile, the upper-middle part of the thigh and the upper arm showed larger variations than the lower part. The ultrasound-assisted liposuction had less blood loss and pain. It resulted in smooth skin without severe complications.</p><p><b>CONCLUSIONS</b>External ultrasound-assisted liposuction is a safe, effective and easily acceptable operation for body contour remodeling. The body circumference variation may have its intrinsic rule, which, to some extent, is meaningful for conducting clinical inquiry and forecasting the operation results.</p>