Over the course of more than 60 years of development, microsurgical techniques have entered the era of intelligence and digitization. This article focuses on the development of microsurgical techniques in the field of tissue repair in China, provides a detailed analysis of the application of microsurgical techniques in the repair of destructive burn wounds and the reconstruction of post-burn scar contracture deformity, and systematically introduces the flap repair strategies in various tissue forms. With advances of science and technology, and breakthroughs in emerging fields such as tissue engineering, regenerative medicine and gene editing, microsurgical techniques have demonstrated tremendous potential in the area of tissue repair, with broad prospects for future applications.

Objective:To explore the clinical effects of various special forms of the descending branch of the lateral circumflex femoral artery (DLCFA) perforator flaps in repairing high-voltage electrical burn wounds on the wrist.Methods:This study was a retrospective observational study. From September 2014 to June 2024, 79 male patients with high-voltage electrical burns on the wrist, aged 20 to 62 years and met the inclusion criteria, were admitted to Beijing Jishuitan Hospital Affiliated to Capital Medical University, with wrist high-voltage electrical burn wound (hereinafter referred to as wrist wound) types being classified as type Ⅱ or type Ⅲ. In the early stage after injury, debridement was performed on the patients' wrists. Based on the wound condition and flap indications, the flow-through, lobed, chimeric, flow-through-lobed, lobed-chimeric, flow-through-chimeric, or flow-through-lobed-chimeric DLCFA perforator flap was employed individually, and the flow-through-chimeric DLCFA perforator flap and tensor fascia lata myocutaneous flap were employed in combination to repair the wounds. The donor site wounds were repaired using direct sutures or skin grafting. The number of various DLCFA perforator flaps resected during surgery and the number of various types of wrist wounds repaired were recorded, as well as the closure status of the donor site wound. The postoperative flap survival, occurrence of vascular crisis, wound or suture site healing, and patency of the reconstructed artery in flow-through flaps were recorded. During follow-up, the appearance of the flap, scar formation, and the presence of thigh muscle herniation were observed.Results:Intraoperatively, 11 flow-through DLCFA perforator flaps were resected to repair 11 type Ⅱ wrist wounds, 13 lobed DLCFA perforator flaps were resected to repair 9 type Ⅱ and 4 type Ⅲ wrist wounds, 16 chimeric DLCFA perforator flaps were resected to repair 16 type Ⅱ wrist wounds, 11 flow-through-lobed DLCFA perforator flaps were resected to repair 5 type Ⅱ and 6 type Ⅲ wrist wounds, 10 lobed-chimeric DLCFA perforator flaps were resected to repair 5 type Ⅱ and 5 type Ⅲ wrist wounds, 6 flow-through-chimeric DLCFA perforator flaps were resected to repair 6 type Ⅱ wrist wounds, 7 flow-through-lobed-chimeric DLCFA perforator flaps were resected to repair 7 type Ⅲ wrist wounds, and 5 flow-through-chimeric DLCFA perforator flaps combined with tensor fascia lata myocutaneous flaps were resected to repair 5 type Ⅲ wrist wounds. Seventy-four patients had their donor site wounds closed by direct suturing, while 5 patients had their donor site wounds closed by skin grafting. Postoperatively, the flaps in 3 patients developed vascular crisis, including 1 case of arterial crisis and 2 cases of venous crises but survived after emergency vascular exploration and other treatments; the remaining flaps survived completely. Postoperatively, 3 patients had seepage beneath their flaps, which were closed after dressing changes; the remaining patients' wounds or suture sites all healed. Anteriography showed that all reconstructed arteries in 35 patients who underwent flow-through flap transplantation were patent postoperatively. During the follow-up period of 3 months to 1 year, 20 patients had bloated flap, while the rest had good flap appearance; linear scars were left in the donor sites that underwent direct wound closure, and the skin-grafted areas of the donor site wounds showed no significant patchy hypertrophic scarring; no thigh muscle herniation occurred.Conclusions:Taking the full advantage of perforator flaps, various special forms of the DLCFA perforator flaps are used to repair the three-dimensionally injury wounds caused by high-voltage electrical burns on the wrist, which not only minimizes the damage to the donor site but also allow the recipient site to be well repaired, showing good appearance in the recent follow-up.

Objective:To explore the clinical effects of sequential treatment of extensive skin and soft tissue injuries of the lower leg accompanied by large segmental tibial defects by free transplantation of anterolateral thigh perforator flap combined with bone transport.Methods:This study was a retrospective observational study. From April 2020 to January 2024, 8 patients with extensive skin and soft tissue injuries of the lower leg accompanied by large segmental tibial defects who met the inclusion criteria were admitted to Beijing Dawanglu Emergency Rescue Hospital. Among them, there were 6 males and 2 females, aged 17 to 58 years. After debridement, the area was 17 cm×8 cm to 30 cm×12 cm, and the length of tibial defect was 9 to 12 cm. Stage Ⅰ surgery was performed by free transplantation of anterolateral thigh perforator flap to repair the extensive skin and soft tissue injuries of the lower leg and using autologous skin graft from the thigh to repair the remaining wound. Stage Ⅱ surgery was performed after wound healing, the external fixation bracket was removed and replaced with an Orthofix unilateral external fixation lengthening frame (hereinafter referred to as external fixation lengthening frame) to transport the proximal tibial osteotomy for repairing the large segmental bone defects. The intraoperative arteriovenous anastomosis and the blood supply of the flap during stage Ⅰ surgery were documented, along with the survival status of the flap/skin graft in the donor and recipient areas postoperatively, and the wound healing time in the recipient area. The time required for bone transport completion, the duration of external fixation retention, and the occurrence of complications during this period were recorded after stage Ⅱ surgery. During follow-up, the occurrence of adverse events in the recipient area was recorded. At the final follow-up, fracture healing of the affected limb was evaluated according to the Paley score, and limb function was observed.Results:In 2 patients, the descending branch of the lateral circumflex femoral artery and the accompanying vein were end-to-end anastomosed with the proximal anterior tibial or posterior tibial artery and vein for antegrade blood supply and antegrade reflux; in 2 patients, the descending branch of the lateral circumflex femoral artery was end-to-end anastomosed with the distal anterior tibial artery for retrograde blood supply, and the accompanying vein of the descending branch of the lateral circumflex femoral artery was end-to-end anastomosed with the proximal anterior tibial vein for antegrade reflux; in 3 patients, the descending branch of the lateral circumflex femoral artery was end-to-end anastomosed with the distal posterior tibial artery for retrograde blood supply, and the accompanying vein of the descending branch of the lateral circumflex femoral artery was end-to-end anastomosed with the distal posterior tibial vein for retrograde reflux; one patient underwent repair of the injury in the affected lower leg using a free cross-leg vascular pedicle flap from the healthy limb. The flaps/skin grafts in the donor and recipient areas of all 8 patients survived, and the wound healing time in recipient area was 14 to 30 days. The bone transport duration of the patients in this group was 93 to 125 days, and the external fixation lengthening frame was continuously retained for 7 to 14 months after the bone transport was stopped; during the bone transport period, 1 patient had pin tract infection, which was controlled after dressing change and enhanced nursing. During the follow-up, there was no ulceration of the wound surface in recipient area, and no osteomyelitis or fracture developed in the affected limb. At the last follow-up, the bone healing evaluation was all excellent; the walking posture and function of the affected limb were basically normal.Conclusions:The application of free transplantation of anterolateral thigh perforator flap combined with bone transport in the sequential treatment of extensive skin and soft tissue injuries of the lower leg accompanied by large segmental tibial defecst can achieve wound healing and functional reconstruction of bone defects, and has great clinical application value.

Objective:To investigate the autophagy level of CD8+T cells in rat model of chronic obstructive pulmonary disease(COPD)and correlation with its number,and to explore the role of autophagy in pathogenesis of COPD.Methods:Thirty-six 6-week-old male SD rats were divided into three groups,including normal control group,COPD group and COPD intervention group.COPD model was established by smoking,and intraperitoneal injection of 3-methyladenine(3-MA)was used for intervention.Lung function of rats was detected by small animal pulmonary function testing,and frequency of CD8+T cells,CD8+memory T cells,CD8+effector T cells in blood and lung of rats were detected by flow cytometry.CD8+T cells were sorted by immunomagnetic beads,and expressions of autophagy protein including LC3-Ⅱ/Ⅰ,Beclin-1 and p62 in CD8+T cells were detected by Western blot.The middle lobe of right lung was collected for histological observation.Results:Infiltration of inflammatory cells and the decline of lung function in COPD group were more obvious than those in normal group.Frequency of CD8+T cells,CD8+effector T cells and CD8+memory T cells in blood and lung of rats in COPD group were significantly higher than those in normal control group(all P<0.05).Level of autophagy protein,LC3-Ⅱ/Ⅰ and Beclin-1 of CD8+T cells in COPD group were significantly higher than that in normal control group,while level of p62 was lower than that in normal control group(P<0.01).CD8+T cells,CD8+effector T cells,CD8+memory T cells in COPD intervention group were significantly lower than those in COPD group(P<0.05).Correlation analysis showed that LC3-Ⅱ/Ⅰ expression level was positively correlated with frequency of CD8+T cells in blood(r=0.667,P<0.01).Expression level of Beclin-1 was positively correlated with frequency of CD8+T cells and CD8+effector T cells in blood(r=0.505,P=0.021;r=0.428,P=0.037).Expression of LC3-Ⅱ/Ⅰprotein was positively correlated with frequency of CD8+T cells and CD8+effector T cells in lung tissue(r=0.474,P=0.019;r=0.549,P=0.006).Expression of Beclin-1 was positively correlated with frequency of CD8+effector T cells in lung tissue(r=0.458,P=0.025).Conclusion:Level of CD8+T cell autophagy is correlated with its number.CD8+T cell autophagy may be involved in the chronic inflam-matory process of COPD,and 3-MA can inhibit COPD inflammation.

Objective To study the pharmacokinetic profile of zidovudine and lamivudine tablets(ZL)in Chinese healthy subjects and to evaluate its bioequivalence and safety.Methods A randomized,open,single-dose,two-sequence,four-cycle and fully replicated crossover bioequivalence trial was conducted in 32 healthy subjects both fasting and postprandial,and two preparations of ZL tablets were administered orally in each cycle,with a washout period of 5 days.The concentrations of zidovudine and lamivudine in plasma were determined using high performance liquid chromatography-tandem mass spectrometry.The pharmacokinetic evaluation index parameters were statistically analyzed using Phoenix WinNonlin version 8.1 data statistical software to evaluate bioequivalence.Results The Cmax of zidovudine under fasting and postprandial conditions between ZL and the reference drugs after a single dose were(3 782.499±1 921.649)vs.(3 543.164±1 946.076)ng·mL-1 and(1 585.827±914.246)vs.(1 667.595±862.945)ng·mL-1,respectively.And the AUC0-t for fasting and postprandial conditions of zidovudine was(3 177.091±819.538)vs.(3 071.375±972.145)h·ng·mL-1 and(2 437.999±478.147)vs.(2 402.725±477.792)h·ng·mL-1,respectively;while the AUC0-∞ were(3 225.674±825.131)vs.(3 093.448±972.340)h·ng·mL-1and(2 464.310±480.790)vs.(2 427.693±477.933)h·ng·mL-1,respectively.The Cmax of a single dose of lamivudine under fasting and postprandial conditions between ZL and the reference drugs were(1 923.329±490.572)vs.(1 830.570±476.947)ng·mL-1 and(1 922.711±589.130)vs.(1 881.857±527.577)ng·mL-1,respectively.The AUC0-t for preprandial and postprandial lamivudine was(7 598.265±1 376.774)vs.(7 283.422±1 356.146)h·ng·mL-1 and(7 554.169±958.379)vs.(7 329.376±924.075)h·ng·mL-1,respectively,whereas the AUC0-∞ were(7 734.038±1 326.907)vs.(7 405.088±1 340.036)h·ng·mL-1 and(7 660.916±958.694)vs.(7 435.102±930.448)h·ng·mL-1,in fasting and fed tests,the 90％confidence intervals(CI)of the geometric mean ratios of the main pharmacokinetic parameters between test and reference preparations were all within the range of 80％-125％,respectively.A total of 37 adverse events occurred during the trial period,including 21 in the fasting group and 16 in the postprandial group,and no serious adverse events occurred.Conclusion The test formulations of zidovudine and lamivudine tablets were bioequivalent and well tolerated in healthy Chinese subjects under fasting and fed conditions compared to the reference tablets.

Objective To study the pharmacokinetic profile of zidovudine and lamivudine tablets(ZL)in Chinese healthy subjects and to evaluate its bioequivalence and safety.Methods A randomized,open,single-dose,two-sequence,four-cycle and fully replicated crossover bioequivalence trial was conducted in 32 healthy subjects both fasting and postprandial,and two preparations of ZL tablets were administered orally in each cycle,with a washout period of 5 days.The concentrations of zidovudine and lamivudine in plasma were determined using high performance liquid chromatography-tandem mass spectrometry.The pharmacokinetic evaluation index parameters were statistically analyzed using Phoenix WinNonlin version 8.1 data statistical software to evaluate bioequivalence.Results The Cmax of zidovudine under fasting and postprandial conditions between ZL and the reference drugs after a single dose were(3 782.499±1 921.649)vs.(3 543.164±1 946.076)ng·mL-1 and(1 585.827±914.246)vs.(1 667.595±862.945)ng·mL-1,respectively.And the AUC0-t for fasting and postprandial conditions of zidovudine was(3 177.091±819.538)vs.(3 071.375±972.145)h·ng·mL-1 and(2 437.999±478.147)vs.(2 402.725±477.792)h·ng·mL-1,respectively;while the AUC0-∞ were(3 225.674±825.131)vs.(3 093.448±972.340)h·ng·mL-1and(2 464.310±480.790)vs.(2 427.693±477.933)h·ng·mL-1,respectively.The Cmax of a single dose of lamivudine under fasting and postprandial conditions between ZL and the reference drugs were(1 923.329±490.572)vs.(1 830.570±476.947)ng·mL-1 and(1 922.711±589.130)vs.(1 881.857±527.577)ng·mL-1,respectively.The AUC0-t for preprandial and postprandial lamivudine was(7 598.265±1 376.774)vs.(7 283.422±1 356.146)h·ng·mL-1 and(7 554.169±958.379)vs.(7 329.376±924.075)h·ng·mL-1,respectively,whereas the AUC0-∞ were(7 734.038±1 326.907)vs.(7 405.088±1 340.036)h·ng·mL-1 and(7 660.916±958.694)vs.(7 435.102±930.448)h·ng·mL-1,in fasting and fed tests,the 90％confidence intervals(CI)of the geometric mean ratios of the main pharmacokinetic parameters between test and reference preparations were all within the range of 80％-125％,respectively.A total of 37 adverse events occurred during the trial period,including 21 in the fasting group and 16 in the postprandial group,and no serious adverse events occurred.Conclusion The test formulations of zidovudine and lamivudine tablets were bioequivalent and well tolerated in healthy Chinese subjects under fasting and fed conditions compared to the reference tablets.

Objective:To investigate the autophagy level of CD8+T cells in rat model of chronic obstructive pulmonary disease(COPD)and correlation with its number,and to explore the role of autophagy in pathogenesis of COPD.Methods:Thirty-six 6-week-old male SD rats were divided into three groups,including normal control group,COPD group and COPD intervention group.COPD model was established by smoking,and intraperitoneal injection of 3-methyladenine(3-MA)was used for intervention.Lung function of rats was detected by small animal pulmonary function testing,and frequency of CD8+T cells,CD8+memory T cells,CD8+effector T cells in blood and lung of rats were detected by flow cytometry.CD8+T cells were sorted by immunomagnetic beads,and expressions of autophagy protein including LC3-Ⅱ/Ⅰ,Beclin-1 and p62 in CD8+T cells were detected by Western blot.The middle lobe of right lung was collected for histological observation.Results:Infiltration of inflammatory cells and the decline of lung function in COPD group were more obvious than those in normal group.Frequency of CD8+T cells,CD8+effector T cells and CD8+memory T cells in blood and lung of rats in COPD group were significantly higher than those in normal control group(all P<0.05).Level of autophagy protein,LC3-Ⅱ/Ⅰ and Beclin-1 of CD8+T cells in COPD group were significantly higher than that in normal control group,while level of p62 was lower than that in normal control group(P<0.01).CD8+T cells,CD8+effector T cells,CD8+memory T cells in COPD intervention group were significantly lower than those in COPD group(P<0.05).Correlation analysis showed that LC3-Ⅱ/Ⅰ expression level was positively correlated with frequency of CD8+T cells in blood(r=0.667,P<0.01).Expression level of Beclin-1 was positively correlated with frequency of CD8+T cells and CD8+effector T cells in blood(r=0.505,P=0.021;r=0.428,P=0.037).Expression of LC3-Ⅱ/Ⅰprotein was positively correlated with frequency of CD8+T cells and CD8+effector T cells in lung tissue(r=0.474,P=0.019;r=0.549,P=0.006).Expression of Beclin-1 was positively correlated with frequency of CD8+effector T cells in lung tissue(r=0.458,P=0.025).Conclusion:Level of CD8+T cell autophagy is correlated with its number.CD8+T cell autophagy may be involved in the chronic inflam-matory process of COPD,and 3-MA can inhibit COPD inflammation.

Over the course of more than 60 years of development, microsurgical techniques have entered the era of intelligence and digitization. This article focuses on the development of microsurgical techniques in the field of tissue repair in China, provides a detailed analysis of the application of microsurgical techniques in the repair of destructive burn wounds and the reconstruction of post-burn scar contracture deformity, and systematically introduces the flap repair strategies in various tissue forms. With advances of science and technology, and breakthroughs in emerging fields such as tissue engineering, regenerative medicine and gene editing, microsurgical techniques have demonstrated tremendous potential in the area of tissue repair, with broad prospects for future applications.

Objective:To explore the clinical effects of various special forms of the descending branch of the lateral circumflex femoral artery (DLCFA) perforator flaps in repairing high-voltage electrical burn wounds on the wrist.Methods:This study was a retrospective observational study. From September 2014 to June 2024, 79 male patients with high-voltage electrical burns on the wrist, aged 20 to 62 years and met the inclusion criteria, were admitted to Beijing Jishuitan Hospital Affiliated to Capital Medical University, with wrist high-voltage electrical burn wound (hereinafter referred to as wrist wound) types being classified as type Ⅱ or type Ⅲ. In the early stage after injury, debridement was performed on the patients' wrists. Based on the wound condition and flap indications, the flow-through, lobed, chimeric, flow-through-lobed, lobed-chimeric, flow-through-chimeric, or flow-through-lobed-chimeric DLCFA perforator flap was employed individually, and the flow-through-chimeric DLCFA perforator flap and tensor fascia lata myocutaneous flap were employed in combination to repair the wounds. The donor site wounds were repaired using direct sutures or skin grafting. The number of various DLCFA perforator flaps resected during surgery and the number of various types of wrist wounds repaired were recorded, as well as the closure status of the donor site wound. The postoperative flap survival, occurrence of vascular crisis, wound or suture site healing, and patency of the reconstructed artery in flow-through flaps were recorded. During follow-up, the appearance of the flap, scar formation, and the presence of thigh muscle herniation were observed.Results:Intraoperatively, 11 flow-through DLCFA perforator flaps were resected to repair 11 type Ⅱ wrist wounds, 13 lobed DLCFA perforator flaps were resected to repair 9 type Ⅱ and 4 type Ⅲ wrist wounds, 16 chimeric DLCFA perforator flaps were resected to repair 16 type Ⅱ wrist wounds, 11 flow-through-lobed DLCFA perforator flaps were resected to repair 5 type Ⅱ and 6 type Ⅲ wrist wounds, 10 lobed-chimeric DLCFA perforator flaps were resected to repair 5 type Ⅱ and 5 type Ⅲ wrist wounds, 6 flow-through-chimeric DLCFA perforator flaps were resected to repair 6 type Ⅱ wrist wounds, 7 flow-through-lobed-chimeric DLCFA perforator flaps were resected to repair 7 type Ⅲ wrist wounds, and 5 flow-through-chimeric DLCFA perforator flaps combined with tensor fascia lata myocutaneous flaps were resected to repair 5 type Ⅲ wrist wounds. Seventy-four patients had their donor site wounds closed by direct suturing, while 5 patients had their donor site wounds closed by skin grafting. Postoperatively, the flaps in 3 patients developed vascular crisis, including 1 case of arterial crisis and 2 cases of venous crises but survived after emergency vascular exploration and other treatments; the remaining flaps survived completely. Postoperatively, 3 patients had seepage beneath their flaps, which were closed after dressing changes; the remaining patients' wounds or suture sites all healed. Anteriography showed that all reconstructed arteries in 35 patients who underwent flow-through flap transplantation were patent postoperatively. During the follow-up period of 3 months to 1 year, 20 patients had bloated flap, while the rest had good flap appearance; linear scars were left in the donor sites that underwent direct wound closure, and the skin-grafted areas of the donor site wounds showed no significant patchy hypertrophic scarring; no thigh muscle herniation occurred.Conclusions:Taking the full advantage of perforator flaps, various special forms of the DLCFA perforator flaps are used to repair the three-dimensionally injury wounds caused by high-voltage electrical burns on the wrist, which not only minimizes the damage to the donor site but also allow the recipient site to be well repaired, showing good appearance in the recent follow-up.

Objective:To explore the clinical effects of sequential treatment of extensive skin and soft tissue injuries of the lower leg accompanied by large segmental tibial defects by free transplantation of anterolateral thigh perforator flap combined with bone transport.Methods:This study was a retrospective observational study. From April 2020 to January 2024, 8 patients with extensive skin and soft tissue injuries of the lower leg accompanied by large segmental tibial defects who met the inclusion criteria were admitted to Beijing Dawanglu Emergency Rescue Hospital. Among them, there were 6 males and 2 females, aged 17 to 58 years. After debridement, the area was 17 cm×8 cm to 30 cm×12 cm, and the length of tibial defect was 9 to 12 cm. Stage Ⅰ surgery was performed by free transplantation of anterolateral thigh perforator flap to repair the extensive skin and soft tissue injuries of the lower leg and using autologous skin graft from the thigh to repair the remaining wound. Stage Ⅱ surgery was performed after wound healing, the external fixation bracket was removed and replaced with an Orthofix unilateral external fixation lengthening frame (hereinafter referred to as external fixation lengthening frame) to transport the proximal tibial osteotomy for repairing the large segmental bone defects. The intraoperative arteriovenous anastomosis and the blood supply of the flap during stage Ⅰ surgery were documented, along with the survival status of the flap/skin graft in the donor and recipient areas postoperatively, and the wound healing time in the recipient area. The time required for bone transport completion, the duration of external fixation retention, and the occurrence of complications during this period were recorded after stage Ⅱ surgery. During follow-up, the occurrence of adverse events in the recipient area was recorded. At the final follow-up, fracture healing of the affected limb was evaluated according to the Paley score, and limb function was observed.Results:In 2 patients, the descending branch of the lateral circumflex femoral artery and the accompanying vein were end-to-end anastomosed with the proximal anterior tibial or posterior tibial artery and vein for antegrade blood supply and antegrade reflux; in 2 patients, the descending branch of the lateral circumflex femoral artery was end-to-end anastomosed with the distal anterior tibial artery for retrograde blood supply, and the accompanying vein of the descending branch of the lateral circumflex femoral artery was end-to-end anastomosed with the proximal anterior tibial vein for antegrade reflux; in 3 patients, the descending branch of the lateral circumflex femoral artery was end-to-end anastomosed with the distal posterior tibial artery for retrograde blood supply, and the accompanying vein of the descending branch of the lateral circumflex femoral artery was end-to-end anastomosed with the distal posterior tibial vein for retrograde reflux; one patient underwent repair of the injury in the affected lower leg using a free cross-leg vascular pedicle flap from the healthy limb. The flaps/skin grafts in the donor and recipient areas of all 8 patients survived, and the wound healing time in recipient area was 14 to 30 days. The bone transport duration of the patients in this group was 93 to 125 days, and the external fixation lengthening frame was continuously retained for 7 to 14 months after the bone transport was stopped; during the bone transport period, 1 patient had pin tract infection, which was controlled after dressing change and enhanced nursing. During the follow-up, there was no ulceration of the wound surface in recipient area, and no osteomyelitis or fracture developed in the affected limb. At the last follow-up, the bone healing evaluation was all excellent; the walking posture and function of the affected limb were basically normal.Conclusions:The application of free transplantation of anterolateral thigh perforator flap combined with bone transport in the sequential treatment of extensive skin and soft tissue injuries of the lower leg accompanied by large segmental tibial defecst can achieve wound healing and functional reconstruction of bone defects, and has great clinical application value.