Biomedical subjects

Zhi-Xiang Zhu

Publications and source records attributed to Zhi-Xiang Zhu.

5 recordsLinked to original sources

PubMed2006

A series of models of non-thermal high voltage electrical injuries.

Although many models of electrical injury have been established, none of them are completely typical of the clinical features of electrical injury. As a result, research based on these models were incapable of explaining many clinical phenomena such as continuous tissue necrosis and also were unable to cope with high ratio of amputation of extremities. In order to investigate the mechanism of electrical injuries and better model the condition with similar clinical characteristics we developed a new model. Seventy-five New Zealand rabbits were employed in this study, of them 45 were used in a preliminary experiment including the selection of the size of electrode plate area, damaged extent, time length of electrical injury and interval length between two injuries and so on. Another 30 rabbits were equally divided into five groups with electrical injury times of 6, 12, 18, 24 and 30 cycles, respectively. Observations were made using clinical anatomical exploration, with quantification using an IDBI scale on the 2nd, 8th, 24th, 48th hours and 5th, 15th days, and TC-99m-DMP isotope scanning and gamma photography at 2nd hour and 5th day in post-injury, respectively. The results showed the effective electric field strength was 17,000 V/m, mean current intensity was 554 mA, average current density was 137 mA/cm(2) beneath the small electrode plate with 21 mA/cm(2) beneath big one, and average increase of tissue temperature was 1.73 degrees C during injury process which excluded the possibility of thermal injury. One single wound injury beneath the small plate of the experimental rabbits with loss of injured extremities from 5th to 15th post-injury days in groups 3-5 and obviously progressive tissue necrosis in and outside the wounds were obtained. A series of electrical injured models from mild, moderate, severe, extra severe, and destructive which was exactly similar to the clinical features of electrical injury cases was established.

Animals↗

PubMed2005

An experimental model of an electrical injury to the peripheral nerve.

OBJECTIVE: Injury to the peripheral nerves is a common complication found in patients suffering from electrical burns. At present, there are many kinds of experimental models for electrical injury, but no report describes an animal-based experimental model for a relatively simple electrical injury to the peripheral nerves. We have designed and constructed a specific device to generate increasingly severe electrical shocks of a known voltage for the experiment. This device can simulate injuries of different degrees (minor, medium and severe) caused by shock to the right sciatic nerve of rats. METHOD: Thirty Sprague-Dawley rats were randomly divided into Group I (3600 V, n=10), Group II (1000 V, n=10) and Group III (500 V, n=10). The voltage required for the electrical shock was generated by the above-mentioned device and was adjusted to deliver 3600, 1000 and 500 V, respectively. The specific voltage, as mentioned above, was delivered three times to the right sciatic nerve of the rats. The shock duration was set to last for 10 ms. The time interval between the shocks was 3 min. Three rats were randomly selected from each group to observe changes in the morphology, electric physiology of the nerve and their histology the first, second and fourth week after injury. RESULTS: All rats survived the injuries. Leg function was partially impaired and swellings occurred on the injured extremity. However, by the second week after the injury the rats had recovered. Digit ulcers were observed by the fourth week after injury in Groups I and II. Neural electric physiology showed that the recovery rate of the neural conduction velocity (RNCV) disappeared in part or in whole immediately after the injury in experimental rats. RNCV recovered up to 65% in Group III and to 7% in Group II by the fourth week after injury, however, RNCV did not recover in Group I at all. Histology showed that blood vessel embolism occurred within the injured nerve. A large number of nerve fibres experienced Waller degeneration while the myelin sheath was vacuolated. The neural plate disintegrated largely by the first week after injury and the myelin sheath disintegrated into a loose structure by the second week after injury in Group I. Group II displayed a similar situation as Group I, wherein some nerve fibres experienced Waller degeneration and disintegration. Regenerative myelin appeared in some rats at about the fourth week after injury. The following changes were seen in Group III: The degree of neural injuries was different. The point of entry of the electric currents showed obvious Waller degeneration and disintegration of the myelin sheath, while some nerves showed a regenerated myelin sheath by the second week after injury. The morphology (such as quantity and diameter) of the injured myelin was basically normal by the fourth week after injury. CONCLUSION: This device can produce controlled injuries to the sciatic nerve giving different degrees of severity (minor, medium and severe), by means of varying the electrical shock voltage and shock duration on the rats. It is a useful model for experimental studies of injuries to peripheral nerves.

Animals↗

PubMed2005

[The experimental researches on the use of triamcinolone acetonide for the prevention of implant capsular contracture].

OBJECTIVE: To explore the use of triamcinolone acetonide for the prevention of implant capsular contracture. METHODS: 20 rabbits were randomly undivided into 2 groups of 10 animals each. Every 10 ml silicone implant was implanted beneath the panniculus carnosus muscle of one rabbit. At the same time, a modified expander catheter was mounted on the implant. This catheter has many lateral holes and the end was blind. Triamcinolone acetonide (10 mg/3 ml) was infused through the expander pot and catheter as the experimental groups. On the other hand, 3 ml saline was used as the control group at 1, 2, and 3 months. At 6 months, measures related to contracture and capsular histology examinations were performed on anesthetized animals. RESULTS: Baker scores, capsular incision width and capsular thickness of the saline groups were evidently higher than that of triamcinolone acetonide groups (P < 0.01). Implant compression of the saline groups was evidently lower than that of triamcinolone acetonide group. Histology revealed a thinner capsules and less fibrous tissue deposition around the triamcinolone acetonide group, as compared with saline group. CONCLUSIONS: It is effective to deliver triamcinolone acetonide to reduction of capsular contracture through the catheter and its pot.

Animals↗

PubMed2004

[Breast reconstruction with multiple miniprostheses].

OBJECTIVE: To evaluate a new technique for breast reconstruction with multiple miniprostheses, METHODS: Each silicone miniprosthesis(10 approximately 15 ml) was implanted one by one beneath the prepared muscle pocket until the desired volume was achieved. RESULTS: Seven patients were treated with the above mentioned technique, including five after gland fibroadenoma excision, one hemangioma excision and one reduction mammoplasty. The results were satisfactory. CONCLUSION: The above mentioned technique with the miniprostheses may be another good way for breast augmentation and breast reconstruction with many advantages such as smaller incision, easy intraoperative assessment of the ideal size of the breast, easy handling the technique, perhaps low incidence of capsular contracture.

Adult↗

PubMed2003

Experience of 14 years of emergency reconstruction of electrical injuries.

Although there have been great advances in the treatment of electrical injuries in the last 20 years, the extremity loss ratio in electrical injuries remains at an unacceptably high level. The primary cause is due to the progressive tissue necrosis which results in the continuous extension of necrosis in the wound, leading to loss of the whole injured extremity. This study reports attempts to break the dangerous tissue necrosis circle and save the form and function of damaged extremities. After 14 years of systematic experimental and clinical studies a successful comprehensive urgent reconstruction alternative (CURA) for electrical injuries is proposed. CURA includes: debriding the wound as early as possible after injury; preserving the vital tissue structures as much as possible, such as nerves, vessels, joints, tendons, bone, even though they have undergone devitalization or local necrosis; repairing these vital tissues during the first surgery if functional reconstruction requires it; protecting the wound bed by covering with tissue flaps of rich blood supply; improving flap survival through moist dressings supported by continuous irrigation beneath the flaps for a 24-72h period after surgery with measures to control local infection; and last, giving general systemic treatment with vasoactive agents and antibiotics. Four hundred and fifty nine wounds in 155 patients suffering from electrical injuries have been successfully treated with this technique between 1986 and 2000 and are reported in this paper. Satisfactory results were obtained with the extremity loss proportion reduced to less than 9% compared with 41.5% during the 10 years before 1984 in the same hospital. The authors suggest that CURA is an effective and workable method for treatment of electrical injuries.

Burns, Electric↗