The long-term use of immunosuppressive agents after organ transplantation is associated with many undesirable side effects which may limit the survival of patients and transplanted organs.To patients and transplant surgeons,organ transplantation tolerance is the ultimate goal to improve patient's quality of life.The clinical state of allograft acceptance termed operational tolerance has remained infrequent in clinical transplantation because of the lack of validated assays or biomarkers predictive of tolerance and the concerns about the safety and ethics of complete withdrawal of immunosuppression.Despite these barriers,a number of investigators have continued to conduct well-designed studies with the long-term goal of inducing clinical transplantation tolerance.This review provides an overviewof the currently successful approaches to achieve clinical operational tolerance,including using immunosuppression slow withdrawal in organ transplantation,transplantation tolerance through mixed chimerism and clinical application of T regulatory cells in tolerance.

Objective To study the temporal distribution of macrophage and its phenotype markers in fibrous capsules around silicone implants.Methods Thirty rats were randomly divided into five groups:days 1,3,7,14 and 35.Silicone prostheses (10 ml) were implanted subcutaneously into backs of rats.On each indicated day,the tissue specimens were collected,fixed in 4％ paraformaldehyde for 24 hours and embedded in paraffin.Immunofluorescence was used to detect temporal distribution of M1/M2 macrophages.Results The number of CD68+ macrophages at day 1 (65.8±12.9) was smaller than that at day 3 (102.8±14.5,P＜0.05) and day 7 (116.8±14.2,P＜0.05);and the number of CD68+ macrophages at day 7 was larger than that at day 14 (56.8±12.9,P＜0.05) and day 35 (21.40±6.35,P＜0.05);the proportion of iNOS+ CD68+ M1 cells at day 1 and day 3 was 0.48±0.13,0.60±0.13,respectively,and they were higher than that at day 7 (0.21±0.03,P＜0.05),day 14 (0.21±0.03,P＜0.05) and day 35 (0.17±0.04,P＜0.05);the proportions of CD206+ CD68+ M2 cells at day 1,day 3,day 7,day 14,day 35 were 0.70±0.06,0.60±0.07,0.70±0.08,0.67±0.02 and 0.60±0.06,respectively.Conclusions After the implantation of silicone prostheses,M1 cells increase in early stages and M2 cells maintain in high level throughout the experiment period.

Objective To observe the effect of botulinum toxin type A (BTX-A) on the rate of skin expansion and the immediate retract rate of skin flaps in rats,and to explore new methods for drug-assisted skin expansion.Methods 18 Sprague-Dawley rats were randomly divided into two groups.After BTX-A or normal saline was injected intradermally into the back marking area,an expander was implanted.The expanders were inflated periodically by injecting normal saline to reach the designated intraexpander pressure.The inflation volume was recorded and the area of marked region was measured regularly.After 4 weeks of expansion,the expanded tissues were harvested and the immediate retract rates were measured.The hematoxylin-eosin staining was performed to observe the thickness of epidermis,dermis and the fibrous capsule,while Masson staining for detection of fibrous capsule collagen.Immunohistochemical staining with α-smooth muscle actin for myofibroblasts was also performed.Results The mean inflation volume and area of marked region of BTX-A group were significantly greater than those of the control group.There were lower immediate retract rate,thinner fibrous capsule,less collagen content and fewer α-SMA positive myofibroblasts in the fibrous capsule of the BTX-A group with statistically significant differences (P ＜ 0.05).There was no signigicant difference in the thicknesses of epidermis and dermis between the two groups (P＞0.05).Conclusions BTX-A can inhibit the formation of fibrous capsule to promote skin expansion,while reducing the immediate retract rate.It possess a potential for assisting effectively skin expansion.

Objective:To explore the choice of skin flap design and clinical effects of skin soft tissue expansion in the treatment of body surface lesions.Methods:From January 2018 to December 2020, the Department of Plastic Surgery, the First Affiliated Hospital of the Air Force Medical University performed skin and soft tissue expansion in 148 patients with scars and nevus, including 83 males and 65 females. The age ranged from 4 to 52 years. According to the distance of the donor area, the expanded flap was divided into adjacent local flap and distal pedicled axial flap. An appropriate volume expander was embedded under the donor area flap. The expander was expanded regularly for 8-24 weeks, and the displacement of expander and other complications were avoided.Results:A total of 212 dilators were implanted in 148 patients, and the damaged area was completely repaired after 1 or 2 dilation operations. The expanded flaps were effectively used. The flap transfer was consistent with the first-stage design, with fewer auxiliary incisions, hidden and inconspicuous scars, and maximum repaired area was 22 cm×18 cm; the incidence of dilator complications (16 cases with 21 dilators) was 9.90%.Conclusions:Paying attention to the reasonable design and selection of flap in stage Ⅰ operation can make effective use of expanded flap in stage Ⅱ operation, fully repair body surface lesions, reduce auxiliary incision and achieve the best repair effect.

Objective: To explore the clinical effects of expanded forehead flaps in repairing midfacial defects. Methods: From January 2003 to December 2018, 19 patients with midfacial defects were admitted to our unit, including 8 males and 11 females, aged 7 to 52 years. One cylindrical expander with rated capacity ranged from 100 to 170 mL was placed in the forehead of patients in the first stage of expansion, and the total water injection volume was about 2 times of the rated capacity of the expander during 1 to 2 months. The area of midfacial defects was 4 cm×2 cm to 9 cm×5 cm after resection in the second stage surgery. Expanded forehead flaps with vascular pedicle of supratrochlear vessels or frontal branch of superficial temporal vessels were used to repair the midfacial defects, with flap size ranging from 5 cm×2 cm to 16 cm×6 cm. The donor sites were closed by direct suturing. Three weeks later, the pedicle was divided. The complications, blood supply after flap transfer and pedicle division, and the treatment effects during follow-up were observed. Results: Among the patients, flaps of 11 patients had vascular pedicle of supratrochlear vessels; flaps of 8 patients had vascular pedicle of frontal branch of superficial temporal vessels. All the flaps survived with no complications and good blood supply after flap transfer and pedicle division. During the follow-up of 6 to 12 months after the third stage surgery of pedicle division of 12 patients, no lower eyelid ectropion occurred, the appearance of the flaps was similar to the surrounding tissue with no swelling. Conclusions The application of expanded forehead flaps can not only repair the defects but also effectively avoid the complication of lower eyelid ectropion, which is a promising method in repairing midfacial defects.

Objective:To investigate the immobilizing effect of full-thickness skin subcutaneous grafting on allogeneic full-thickness skin graft in rats.Methods:The experimental research method was used. The inbred male Brown-Norway rats ( n=10) and Lewis rats ( n=10) were used as donors and recipients respectively. After subcutaneously full-thickness separation of a 2.2 cm×2.2 cm area on the nape of the recipient rat, a full-thickness skin of 2.0 cm×2.0 cm taken from the abdomen of the donor rat was subcutaneously grafted, and the donor site was pulled together and sutured. The autologous skin over the allograft in the recipient rat was excised 5-6 d after grafting, and the stitches were removed 7 d after excision. Within 2 months after grafting, the feeding, activity, and survival of the donor and recipient rats, behavior of tearing and scratching the wounds of the recipient rats, the wound condition after autologous skin excision in recipient rats, and the survival and hair growth of the grafted allogeneic skin were observed. Results:Within 2 months after grafting, the donor and recipient rats all ate normally and could move freely with no abnormal death. No tearing or scratching of the wounds occurred in recipient rats. There was a small amount of exudation and partial epidermal desquamation after autologous skin excision in recipient rats. All transplanted allografts survived, which were free of infection and necrosis, with new hairs growing out smoothly.Conclusions:The immobilizing method of full-thickness skin subcutaneous grafting of allogeneic full-thickness skin graft in rats is simple and time-saving without postoperative dressing change, with reliable pressure fixation and high survival rate of skin grafts, which can be promoted for animal skin grafting models.

Objective:To investigate the clinical effects of expanded frontal flap and flip scar flap in repairing partial nasal defect.Methods:A retrospective observational study was conducted. From January 2012 to January 2022, 26 patients with partial nasal defects who met the inclusion criteria were admitted to the First Affiliated Hospital of Air Force Medical University, including 19 males and 7 females, aged 5 to 61 years. The surgery was performed in 4 stages. In the first stage, a rectangular skin and soft tissue expander (hereinafter referred to as expander) with suitable rated capacity was planted in frontal region and expanded by injecting water regularly. In the second stage, flip scar flap was grafted to reconstruct nasal inner lining, whose area was about 10% larger than the area of defect. The expanded frontal flap with pedicle was transferred to repair the nasal defect, whose pedicle was supraorbital vessel or supratrochlear vessel on the contralateral side of the defect, and the area of expanded flap was 20% larger than the nasal defect area after resection and flipping of scar flap. The donor site of expanded flap was sutured directly. After 3 weeks of flap transferring, the flap was delayed in the third stage. After 1 week of delaying operation, the pedicle of flap was cut off in the fourth stage. The number, rated capacity, injection volume, and expansion time of embedded expanders were recorded. The occurrences of complications including infection, hematoma, ulceration of expanded flap after the first stage operation, and blood supply disorder or necrosis of flap after operation in the second and fourth stages were observed. All the patients were followed up for 1 year at least, and the color of flap, scar of frontal donor site, symmetry of bilateral eyebrows, and the nasal appearance and ventilated function of external nasal tract were observed.Results:A total of 26 expanders were embedded in 26 patients. The rated capacity of expanders ranged from 100 to 300 mL. The injection volume was 1.0 to 1.5 times of the rated capacity of expanders. The expansion time ranged from 2.5 to 4.0 months, with an average time of 3 months. There were no complications occurred after each operation. The follow-up showed that the color of flap was similar to the normal nasal skin, the scar of frontal region was not obvious, the bilateral eyebrows were basically symmetrical, the nose had excellent appearance, ventilation function of external nasal tract was not affected, while some of the patients had downward rotation or unapparent tip-defining point of nose.Conclusions:Using the flip scar flap to reconstruct the nasal inner lining and pre-expanded frontal flap to reconstruct the nasal skin, without free cartilage transplantation to repair the partial nasal defects can achieve satisfied nasal appearance post operation, without abnormal external nasal ventilation function.

Objective:To explore the clinical effect of pre-expanded flap on the treatment of perioral scar.Methods:The clinical data on the treatment of perioral scar with pre-expanded flap in the Department of Plastic and Reconstructive Surgery of the First Affiliated Hospital of Air Force Medical University from March 2009 to July 2019 were analyzed retrospectively. The pre-expanded flap composed of the pre-expanded local flap, the pre-expanded deltopectoral flap, the pre-expanded submental flap, and the pre-expanded frontal branch flap of the superficial temporal artery. Generally, the surgical procedure was divided into three stages, which included stage one: skin soft tissue expander implantation; stage two: pre-expanded flap design and transfer; stage three: delay of pre-expanded skin flap, and the amputation of the pedicle. The pre-expanded local flap did not require cutting off the pedicle. Selective laser hair removal was applied to pre-expanded frontal branch flap of superficial temporal artery to repair the scar. The blood circulation and the survival of the metastatic flap were observed after the operation. The appearance and function of the donor and recipient areas were followed up.Results:A total of 47 patients aged between 7 to 50 years old comprising 21 males and 26 females with perioral scars were enrolled, with an average age of 20 years old. Eight cases were treated with pre-expanded local flap. Twenty five cases were treated with pre-expanded deltopectoral flap, 3 cases were treated with pre-expanded deltopectoral flap combined with a pre-expanded local skin flap, 5 cases were treated with pre-expanded submental flap, 6 cases were treated with pre-expanded frontal branch flap of the superficial temporal artery. Postoperative follow-up time ranged from 3 to 108 months (mean 57 months). In all the patients, the perioral scars were repaired, with significant alleviation in mouth opening limitation. The color and texture of the transferred flap were similar to the surrounding skin, and the appearance was satisfactory.Conclusions:The pre-expanded flap is a good approach for the treatment of perioral scar.

Objective:To explore the clinical effect of pre-expanded flap on the treatment of perioral scar.Methods:The clinical data on the treatment of perioral scar with pre-expanded flap in the Department of Plastic and Reconstructive Surgery of the First Affiliated Hospital of Air Force Medical University from March 2009 to July 2019 were analyzed retrospectively. The pre-expanded flap composed of the pre-expanded local flap, the pre-expanded deltopectoral flap, the pre-expanded submental flap, and the pre-expanded frontal branch flap of the superficial temporal artery. Generally, the surgical procedure was divided into three stages, which included stage one: skin soft tissue expander implantation; stage two: pre-expanded flap design and transfer; stage three: delay of pre-expanded skin flap, and the amputation of the pedicle. The pre-expanded local flap did not require cutting off the pedicle. Selective laser hair removal was applied to pre-expanded frontal branch flap of superficial temporal artery to repair the scar. The blood circulation and the survival of the metastatic flap were observed after the operation. The appearance and function of the donor and recipient areas were followed up.Results:A total of 47 patients aged between 7 to 50 years old comprising 21 males and 26 females with perioral scars were enrolled, with an average age of 20 years old. Eight cases were treated with pre-expanded local flap. Twenty five cases were treated with pre-expanded deltopectoral flap, 3 cases were treated with pre-expanded deltopectoral flap combined with a pre-expanded local skin flap, 5 cases were treated with pre-expanded submental flap, 6 cases were treated with pre-expanded frontal branch flap of the superficial temporal artery. Postoperative follow-up time ranged from 3 to 108 months (mean 57 months). In all the patients, the perioral scars were repaired, with significant alleviation in mouth opening limitation. The color and texture of the transferred flap were similar to the surrounding skin, and the appearance was satisfactory.Conclusions:The pre-expanded flap is a good approach for the treatment of perioral scar.

[Objective] To compare the clinicopathological characteristics of localized prostate cancers between peripheral zone and transition zone and to evaluate biochemical recurrence-free survival rates between the two groups following radical prostatectomy. [Methods] Between February 2016 and August 2021, prostate cancer candidates meeting the eligibility criteria of the study were retrospectively enrolled and divided into transition zone group and peripheral zone group based on the zonal origin. The patients were followed regularly after radical prostatectomy. Unpaired t-test, χ²-test and Mann-Whitney U-test were used to compare age, serum prostate specific antigen (PSA), tumor volume, Gleason score, laterality of positive biopsy core, mean percentage of positive biopsy cores, clinical/pathological stage, seminal vesicle invasion, lymph node metastasis, and positive surgical margin between the two groups. The biochemical recurrence-free survival rates of the two groups were evaluated by Kaplan-Meier and the differences were determined by log-rank test. [Results] A total of 273 cases were included in the study, among which 176 were peripheral zone cancers and 97 were transition zone cancers. The mean tumor volume of the transition zone group was greater than that of peripheral zone group (P=0.002). The serum PSA of transition zone group was higher than that of the latter (P=0.047); however, both mean percentage of positive biopsy cores and the percentage of seminal vesicle invasion were higher in transition zone group than in peripheral zone group (P=0.028, 0.047). Furthermore, there was no significant difference in biochemical recurrence-free survival rate between the two groups (P=0.783). [Conclusion] Despite the greater tumor volume and higher PSA compared with those in peripheral zone cancers, transition zone cancers have similar biochemical recurrence-free survival rates following radical prostatectomy, suggesting that transition zone cancers may have a lower degree of aggressiveness than the latter.