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Objective:To identify the genetic variation in a mucopolysaccharidosis type Ⅱ(MPS Ⅱ)family, and conduct a functional study of iduronate-2-sulfatase(IDS): c.323A>C.Methods:A five-generation MPS Ⅱ family of 83 individuals including 4 patients from northern China was collected. Urine mucopolysaccharide and Alder-Reilly body were tested to assist the clinical diagnosis of MPS Ⅱ. IDS enzyme activity was detected on core family members. By the whole exome sequencing of a MPS Ⅱ patient in this family and bioinformatics analysis, the variant was screened and further identified by PCR-Sanger sequencing. Finally, to validate the function of the variant in vitro, the wild-type IDS overexpression plasmid(pCMV-hIDS-WT)and the IDS overexpression plasmid carrying the mutation site(pCMV-hIDS-c.323A>C)were transfected into COS-7 cells and the IDS activity was detected. Results:The proband(Ⅳ3)and Ⅳ4 were diagnosed as MPS Ⅱ by urine mucopolysaccharide, Alder-Reilly body, and IDS enzyme activity tests. Ⅳ3, Ⅳ4, Ⅲ19, and Ⅲ32 were determined to carry IDS: c.323A>C missense variant through the whole-exome sequencing, and diagnosed as MPS Ⅱ. Meanwhile, Ⅱ2, Ⅱ4, Ⅱ8, Ⅱ12, Ⅱ14, Ⅲ5, Ⅲ7, Ⅳ14 in the MPS Ⅱ family carried IDS: c.323A>C missense variant, and were excluded as MPS Ⅱ. The in vitro experiment in COS-7 cells showed that the missense mutation led to a significant decrease in IDS enzyme activity. Conclusion:The variant IDS: c.323A>C: p.Y108S significantly decreases the activity of IDS enzyme in vivo and in vitro, and it is identified as a pathogenic variant for MPS Ⅱ.
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Objective:To investigate the efficacy of 3D-printed quantitative bone implants assisting second-stage Masquelet technique for the treatment of long-segment bone defect following Gustilo type IIIB and IIIC tibial fractures.Methods:A retrospective case series analysis was made on 26 patients with long-segment bone defect following Gustilo type IIIB and IIIC tibial fractures treated in Wuxi Ninth People′s Hospital from July 2015 to December 2020, including 20 males and 6 females; aged 19-63 years [(46.5±4.5)years]. Gustilo classification was type IIIB in 23 patients and type IIIC in 3. In the first stage, all patients had thoroughly emergent debridement, removal of all free bone pieces, restoration of the length and force line plus externally fixion, and vacuum sealing drainage (VSD) of the residual wound. After 2-7 days, the external fixation was removed and replaced by internal fixation, with the bone cement filling in the defect area and the free flap covering the wound. The length of tibial bone defect was 5-14 cm [(6.3±0.4)cm], and the tibial defect volume was 12.2-73.1 cm 3 [(33.6±9.2)cm 3]. In the second stage (6-19 weeks after injury), the bone cement was removed, followed by autologous bone grafting. Prior to bone grafting, digital technology was used to accurately calculate the bone defect volume, and an equal volume of bone harvesting area was designe to produce the 3D printed osteotomy template. Bone grafting was conducted after bone removal according to the osteotomy template during operation. The success rate of one-time iliac bone extraction, bone harvesting time, and bleeding volume were recorded. Pain in the bone extraction area was evaluated by visual analogue score (VAS) at 1 day and 1 month after operation and at the last follow-up. Wound healing, complications, and bone healing were observed. Life quality was evaluated by health survey brief form (SF-36) including scores of physical component summary (PCS) and mental component summary (MCS) before bone grafting and at the last follow-up. Results:All the patients were followed up for 13-53 months [(32.3±12.5)months]. One-time iliac bone extraction was successful in all the patients. Bone harvesting time was 15-30 minutes [(21.0±2.5)minutes]. The bleeding volume was 50-120 ml [(62.3±29.0)ml]. The VAS was 1-4 points [(1.2±0.9)points] at 1 day after operation, higher than these (0.0±0.0)points at 1 month after operation and at the last follow-up (all P<0.01). Totally, 25 patients obtained wound healing after operation, except for 1 patient with superficial wound infection after bone grafting that was healed by dressing change. There was 1 patient with bone infection after 3 months of bone grafting that was healed by repeated surgery with Masquelet technique in the first and second stage. Besides, 2 patients had symptoms of cutaneous nerve injury in the iliac donor area. The time of bone healing was 4-7 months [(5.8±0.8)months]. The scores of PCS and MCS in SF-36 at the last follow-up were (73.6±12.8)points and (83.6±13.2)points, significantly higher than those before bone grafting [(46.8±0.5)points, (60.7±2.0)points] (all P<0.01). Conclusion:Second-stage Masquelet technique with 3D printed quantitative bone implants for the treatment of long-segment bone defect following Gustilo type IIIB and IIIC tibial fractures is associated with shortened bone harvesting time, attenuated pain, reduced complications, accelerated bone healing and improved function.
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Objective To discuss the clinical application of reverse dorsal metatarsal artery perforator flap for reconstruction of forefoot soft tissue defects.Methods Since January,2008 to March,2016,43 patients with forefoot soft tissue defect due to various causes were reconstructed with the flap based on dorsal metatarsal artery perforator.Dorsal pedis was used as a donor site with dorsal metatarsal artery perforator as the donor artery.The flap size varied from 2.0 cm × 4.0 cm to 6.0 cm × 8.0 cm.Among them,27,8,4 and 4 cases were reconstructed with flap based on first,second,third and fourth dorsal metatarsal artery perforator flap respectively.Results All the patients were followed-up which ranged from 3 months to 24 months.Six flaps suffered from post operative venous congestion.Out of 6,4 survived with early emergency management while the remaining 2 suffered epidermal necrosis which survived with regular dressing change.Eventually,all the flaps survived.They had good texture and they were elastic,good-looking and very wear-resisting.Walking function was normal.Conclusion Reverse dorsal metatarsal artery perforator flap is an ideal choice in reconstruction of small to medium sized soft tissue defects of forefoot.