Search

Abstract Wild‐type sortase A is an important virulence factor displaying a diverse array of proteins on the surface of bacteria. This protein display relies on the transpeptidase activity of sortase A, which is widely engineered to allow protein ligation and protein engineering based on the interaction between sortase A and peptides. Here an unknown interaction is found between sortase A from Staphylococcus aureus and nucleic acids, in which exogenously expressed engineered sortase A binds oligonucleotides in vitro and is independent of its canonical transpeptidase activity. When incubated with mammalian cells, engineered sortase A further mediates oligonucleotide labeling to the cell surface, where sortase A attaches itself and is part of the labeled moiety. The labeling reaction can also be mediated by many classes of wild‐type sortases as well. Cell surface GAG appears involved in sortase‐mediated oligonucleotide cell labeling, as demonstrated by CRISPR screening. This interaction property is utilized to develop a technique called CellID to facilitate sample multiplexing for scRNA‐seq and shows the potential of using sortases to label cells with diverse oligonucleotides. Together, the binding between sortase A and nucleic acids opens a new avenue to understanding the virulence of wild‐type sortases and exploring the application of sortases in biotechnology.

Objective: Management of large irregular wounds in children had been confusing plastic and reconstructive surgeons. Herein, this study was aimed to propose a new treatment method based on the principle of adapting different recipient zones to overcome the intractable wounds, simplifying and programing the design process of targeted flaps for covering large irregular soft-tissue defects. Patients and methods: From January 2009 to December 2020, 31 children (9 girls and 22 boys) aged 3–16 years (mean 9.8 years) underwent multiple modular flaps with edge to edge splicing reconstruction of the lower extremities. All the wounds were large with non-adjacent defects and with or without a dead space. Several variants of flaps were harvested according to the needs and reconstruction requirements of patients. Results: A total of 71 flaps were harvested from 31 patients and all flaps donor sites received primary closure. Nine patients underwent split-thickness skin grafting, and three cases of flaps survived from vascular crisis by rebuilding the vessels and the rest accepting LD flap transplants. And five partial necrosis of the distal epidermis flaps recovered using skin grafting and dressing change. No major complication was encountered in other patients and donor sites, except one heel ulcer. During the follow-up (ranging from 16 to 38 months, mean 27.7 months), aesthetic and functional results of reconstructed limbs were satisfactory in all patients. Conclusions: The Individualized design program of multiple flaps for adapting different recipient zones is an alternative for repairing large irregular soft-tissue defects in children, beneficial for plastic and reconstructive surgeons to simplify and program the process of designing and perform multiple flaps to achieve this goal. Level of evidence: III, Retrospective.

Abstract Background Application of the thoracodorsal artery perforator (TDAP) flap is known to be a popular and reliable method for extremity reconstruction. This manuscript presents our clinical outcomes in reconstructing soft tissue defects using simple and advanced TDAP flaps. Methods From 2013 to 2022, 53 patients with a mean age of 23 years (ranging from 2 to 72 years) underwent reconstructive surgery with different patterns of free TDAP flaps, including chimeric TDAP flaps, double skin paddle TDAP flaps, flow-through TDAP flaps, conjoined TDAP flaps, and microdissected debulking TDAP flaps. Results All TDAP flaps survived. The size of the TDAP skin paddle ranged between 5 × 3 and 25 × 10 cm2. Primary closure of the donor site was achieved in all patients in the simple application group, and one patient in the advanced application group underwent partial skin grafting. Partial flap loss occurred in one case in the simple TDAP flap group and four cases in the advanced application group. There was one case of flap bulkiness and two cases of scar hyperplasia in the simple TDAP flap group. The mean follow-up duration was 11 months (4–46 months). Conclusions The free TDAP flap, with five types of advanced applications, makes it versatile for reconstructing different kinds of soft tissue defects of the extremities that can be used to achieve individualized defect reconstruction, minimize donor site morbidities, and an aesthetic appearance.

Summary: The increasing emergence of Cas9 variants has attracted broad interest, as these variants were designed to expand CRISPR applications. New Cas9 variants typically feature higher editing efficiency, improved editing specificity, or alternative PAM sequences. To select Cas9 variants and gRNAs for high-fidelity and efficient genome editing, it is crucial to systematically quantify the editing performances of gRNAs and develop prediction models based on high-quality datasets. Using synthetic gRNA-target paired libraries and next-generation sequencing, we compared the activity and specificity of gRNAs of four SpCas9 variants. The nucleotide composition in the PAM-distal region had more influence on the editing efficiency of HiFi Cas9 and LZ3 Cas9. We further developed machine learning models to predict the gRNA efficiency and specificity for the four Cas9 variants. To aid users from broad research areas, the machine learning models for the predictions of gRNA editing efficiency within human genome sites are available on our website.

Abstract Flap necrosis, the most prevalent postoperative complication of reconstructive surgery, is significantly associated with ischaemia–reperfusion injury. Recent research indicates that exosomes derived from bone marrow mesenchymal stem cells (BMSCs) hold potential therapeutic applications in several diseases. Traditionally, BMSCs are cultured under normoxic conditions, a setting that diverges from their physiological hypoxic environment in vivo. Consequently, we propose a method involving the hypoxic preconditioning of BMSCs, aimed at exploring the function and the specific mechanisms of their exosomes in ischaemia–reperfusion skin flaps. This study constructed a 3 × 6 cm2 caudal superficial epigastric skin flap model and subjected it to ischaemic conditions for 6 h. Our findings reveal that exosomes from hypoxia-pretreated BMSCs significantly promoted flap survival, decrease MCP-1, IL-1β, and IL-6 levels in ischaemia–reperfusion injured flap, and reduce oxidative stress injury and apoptosis. Moreover, results indicated that Hypo-Exo provides protection to vascular endothelial cells from ischaemia–reperfusion injury both in vivo and in vitro. Through high-throughput sequencing and bioinformatics analysis, we further compared the differential miRNA expression profiles between Hypo-Exo and normoxic exosomes. Results display the enrichment of several pathways, including autophagy and mTOR. We have also elucidated a mechanism wherein Hypo-Exo promotes the survival of ischaemia–reperfusion injured flaps. This mechanism involves carrying large amounts of miR-421-3p, which target and regulate mTOR, thereby upregulating the expression of phosphorylated ULK1 and FUNDC1, and subsequently further activating autophagy. In summary, hypoxic preconditioning constitutes an effective and promising method for optimizing the therapeutic effects of BMSC-derived exosomes in the treatment of flap ischaemia–reperfusion injury.

Abstract Objectives This study investigated whether exosomes from LPS pretreated bone marrow mesenchymal stem cells (LPS pre-MSCs) could prolong skin graft survival. Methods The exosomes were isolated from the supernatant of MSCs pretreated with LPS. LPS pre-Exo and rapamycin were injected via the tail vein into C57BL/6 mice allografted with BALB/c skin; graft survival was observed and evaluated. The accumulation and polarization of macrophages were examined by immunohistochemistry. The differentiation of macrophages in the spleen was analyzed by flow cytometry. For in vitro, an inflammatory model was established. Specifically, bone marrow-derived macrophages (BMDMs) were isolated and cultured with LPS (100 ng/ml) for 3 h, and were further treated with LPS pre-Exo for 24 h or 48 h. The molecular signaling pathway responsible for modulating inflammation was examined by Western blotting. The expressions of downstream inflammatory cytokines were determined by Elisa, and the polarization of macrophages was analyzed by flow cytometry. Results LPS pre-Exo could better ablate inflammation compared to untreated MSC-derived exosomes (BM-Exo). These loaded factors inhibited the expressions of inflammatory factors via a negative feedback mechanism. In vivo, LPS pre-Exo significantly attenuated inflammatory infiltration, thus improving the survival of allogeneic skin graft. Flow cytometric analysis of BMDMs showed that LPS pre-Exo were involved in the regulation of macrophage polarization and immune homeostasis during inflammation. Further investigation revealed that the NF-κB/NLRP3/procaspase-1/IL-1β signaling pathway played a key role in LPS pre-Exo-mediated regulation of macrophage polarization. Inhibiting NF-κB in BMDMs could abolish the LPS-induced activation of inflammatory pathways and the polarization of M1 macrophages while increasing the proportion of M2 cells. Conclusion LPS pre-Exo are able to switch the polarization of macrophages and enhance the resolution of inflammation. This type of exosomes provides an improved immunotherapeutic potential in prolonging graft survival.

Abstract Background It was always challenging to accurately and effectively reconstruct the complicated defects with three-dimensional tissue deficits in the extremities. Muscle-chimeric perforator flap is an excellent choice for repairing those complicated wound. However, problems like donor-site morbidity and time-consuming intramuscular dissection still exist. This purpose of this study was to present a novel design of the thoracodorsal artery perforator (TDAP) chimeric flap for the customized reconstruction of complex three-dimensional tissue defects in the extremities. Methods From January 2012 to June 2020, 17 patients with complex three-dimensional deficits in the extremities were retrospectively analyzed. All patients in this series underwent extremity reconstruction using latissimus dorsi (LD)-chimeric TDAP flap. Three different types of LD-chimeric TDAP flaps were performed. Results A total of seventeen TDAP chimeric flaps were successfully harvested for the reconstruction of those complex three-dimensional defects in extremities. Among them, Design Type A flaps were used in 6 cases, Design Type B flaps were performed in 7 cases, and Design Type C flaps were used in the remaining 4 cases. The sizes of the skin paddles ranged from 6 cm × 3 cm to 24 cm × 11 cm. Meanwhile, the sizes of the muscle segments ranged from 3 cm × 4 cm to 33 cm × 4 cm. All the flaps survived. Nevertheless, one case required re-exploration owing to venous congestion. Moreover, the primary closure of the donor site was successfully achieved in all patients, and the mean follow-up time was 15.8 months. Most of the cases displayed satisfactory contour. Conclusion The LD-chimeric TDAP flap is available for the reconstruction of complicated defects with three-dimensional tissue deficits in the extremities. It provided a flexible design for customized coverage of complex soft tissue defects with limited donor site morbidity.

Abstract Background Vascular malformations are common but complicated types of disease in infants, with unclear causes and lack of effective prevention. The symptoms usually do not disappear and tend to progress without medical intervention. It is extremely necessary to choose correct treatment options for different types of vascular malformations. A large number of studies have confirmed that sclerotherapy has a tendency to become the first-line treatment in near future, but it is also associated with mild or severe complications. Furthermore, to our knowledge, the serious adverse event of progressive limb necrosis has not been systematically analyzed and reported in the literature. Case presentation Three cases (two females and one male) were presented who were all diagnosed as vascular malformations and were treated by several sessions of interventional sclerotherapy. Their previous medical records showed the use of several sclerosants in different sessions including Polidocanol and Bleomycin. The sign of limb necrosis did not occur during the first sclerotherapy, but after the second and third sessions. Furthermore, the short-term symptomatic treatment could improve the necrosis syndrome, but could not change the outcome of amputation. Conclusion Sclerotherapy undoubtedly tends to be the first-line treatment in near future, but the adverse reactions still remain major challenges. Awareness of progressive limb necrosis after sclerotherapy and timely management by experts in centers of experience of this complication can avoid amputation.

Objective: Ischemia/reperfusion (I/R) injury is an inevitable dilemma when previously ischemic multiple organs and tissues are returned to a state of blood flow, with confirming a critical role of ferroptosis in molecular, pathway mechanisms, subcellular structure. Discovering the potential relationship may provide useful approaches for the clinical treatment and prognosis of the pathophysiological status of IRI. Therefore, a comprehensive visualization and scientometric analysis were conducted to systematically summarize and discuss the “ferroptosis in ischemia reperfusion injury” research to demonstrate directions for scholars in this field. Methods: We retrieved all publications focusing on I/R injury and ferroptosis from the Web of Science Core Collection (WoSCC), published from 2013 to October 2022. Next, scientometric analysis of different items was performed using various bibliometrics softwares to explore the annual trends, countries/regions, institutions, journals, authors and their multi-dimensional relationship pointing to current hotspots and future advancement in this field. Results: We included a total of 421 English articles in set timespan. The number of publications increased steadily annually. China produced the highest number of publications, followed by the United States. Most publications were from Central South University, followed by Sichuan University and Wuhan University. The most authoritative academic journal was Oxidative Medicine and Cellular Longevity. Cell occupied the first rank of co-cited journal list. Andreas Linkermann and Scott J Dixon may have the highest influence in this intersected field with the highest number of citations and co-cited references respectively. The essential biological reactions such as oxidative stress response, lipid peroxidation metabolism, anti-inflammmatory and pro-inflammatory procedure, and related molecular pathways were knowledge base and current hotspots. Molecules pathways exploration, effective inhibition of I/R injury and promising strategy of improving allografts may become future trends and focuses. Conclusions: Research on ferroptosis in I/R injury had aroused great interest recently. This first bibliometric study comprehensively analyzed the research landscape of ferroptosis and I/R injury, and also provided a reliable reference for related scholars to facilitate further advancement in this field.

Abstract Background Iliac bone flap with deep circumflex iliac artery is a common option in the treatment of Osteonecrosis of the femoral head (ONFH), and dissection of iliac bone flap is the key step for successful operation. This paper aims to introduce a new operative technique for dissecting iliac bone flap with deep circumflex iliac artery based on analysis of its advantages. Methods A total of 49 patients treated by retrograde anatomy and 52 patients treated by anterograde anatomy from January 2010 to December 2020 were recruited. The two groups were then compared in terms of the preoperative baseline conditions, intraoperative data, and postoperative Harris hip score (HHS). Results Compared with the retrograde anatomy group, the anterograde anatomy group had a significantly longer operating time, a significantly heavier intraoperative blood loss, a significantly higher rate of donor complication morbidity, a significantly higher rate of donor–recipient delayed healing, a significantly higher failure rate of iliac bone flap resection, a significantly higher rate of lateral femoral cutaneous nerve (LFCN) injury, and a significantly higher rate of ectopic ossification. No difference was found in postoperative HHS score between the two groups. Conclusion As a new operative technique that can accurately locate the nutrient vessels of the iliac bone flap and quickly dissect the iliac bone flap with deep circumflex iliac artery while maintaining a comparable clinical effect, retrograde anatomy exhibited distinct advantages over anterograde anatomy in terms of simpler intraoperative operation, safer dissection, shorter operation time, lower blood loss, and fewer donor complications. Level of evidence III, Retrospective.

Background: Perforator flaps are widely used in hand microsurgery to reconstruct and repair soft tissue injuries. However, ischemia and subsequent ischemia-reperfusion injury may cause distal necrosis of the flap. Itaconic acid (IA) is a modulator of macrophage function, which exerts anti-inflammatory effects in macrophage activation. Methods: The necrotic area of the flap was detected by measuring the flap temperature with an infrared thermometer. Flap cell apoptosis was detected by TUNEL staining and Western blot analysis of the apoptosis-associated proteins Bcl-2 and Bax. HE staining was used to detect angiogenesis of the skin flaps. CD31 was detected to identify positive vascular expression, and the survival of choke vessels in different areas of the skin flap was assessed by arteriography. In addition, Western blot was performed to quantify the expressions of VEGF, Nrf2, LC3II, SQSTM1, and CTSD. Results: Itaconic acid raises VEGF protein levels in skin flaps and the number of CD31-positive vessels. The skin flaps in the IA treatment group exhibited higher neovascularization and less necrosis than those in the control group. The results of TUNEL staining and Western blot revealed that Itaconic acid attenuated apoptosis in the ischemic area of flap. The combination of itaconic acid and Nrf2 inhibitor ML385 reversed this beneficial effect. The results revealed that itaconic acid attenuated apoptosis, enhanced angiogenesis, and enhanced autophagy. Conclusion: In summary, our findings indicate that itaconic acid might be an effective treatment to reduce flap necrosis. Additionally, this study identified a novel mechanism for the effects of itaconic acid on flap survival.

It is still a challenge to accurately identify off-target endonuclease edits. Here the authors report PEAC-seq using a Prime Editor to insert a tag to the editing sites and enrich the tagged regions with site-specific primers for sequencing: they show that PEAC-seq could identify DNA translocations.

Objective The aim of the present study was to report a novel nomenclature system for extended latissimus dorsi musculocutaneous (LD) flaps. To evaluate the clinical application and surgical efficacy of the different extended LD flaps for large wounds in the extremities. Methods From January 2004 to December 2018, 72 consecutive patients who received extended LD flaps were retrospectively analyzed. Patients' ages ranged from 2 to 68 years with 37 males and 35 females. All wounds were extensive in either the upper or lower limbs, while the skin defect area ranged from 18 cm × 10 cm to 37 cm × 21 cm. Forty‐one wounds were located in the calf, 18 in the foot and ankle, six in the shoulder and upper arm, four in the thigh, and three at the knee joint. Twenty‐eight patients had fractures, and six of these patients with segmental bone defects (ranging in size from 3 to 7 cm) required secondary orthopaedic procedures. Single‐ and double‐wing extended LD flaps were designed and harvested according to the shape of the wounds. Results The flaps received consisted of 64 single‐wing and eight double‐wing extended LD flaps, and the mean flap harvest time was 56.2 min. The donor sites were closed primarily for all patients. Additional subcutaneous veins were anastomosed to the recipient's vessels in 14 patients. The venous crisis was noticed on the first postoperative day in four cases. Two flaps were salvaged after emergency re‐exploration, and another two patients' flaps were necrosed. In these two patients, lower limb amputation and extended LD flap on the other side were used, respectively, for the final treatment. The wounds healed well, providing reliable soft tissue coverage and good contour in the reconstructed areas. Six patients had segmental bone defects that required secondary orthopaedic procedures, two patients were repaired with vascularized iliac crest bone grafts, and another four patients were reconstructed by the Ilizarov technique. All the patients' bone defects achieved union and most patients achieved good functional recovery at the recipient site. The mean follow‐up was 15.7 months (range, 10–56 months). No significant donor site morbidities limiting patients' daily activities occurred during the follow‐up. Eight patients developed a donor site hypertrophic scar, three patients on the back, and five on the anterolateral thigh. Conclusion Single‐ and double‐wing extended LD flaps are simple and reliable methods for large skin and soft tissue defects in the extremity, with good functional and aesthetic results.

Osteonecrosis of the femoral head (ONFH) is a common refractory orthopedic disease, which is one of the common causes of hip pain and dysfunction. ONFH has a very high disability rate, which is associated with a heavy burden to patients, families, and society. The pathogenesis of ONFH is not completely clear. At present, it is believed that it mainly includes coagulation dysfunction, abnormal lipid metabolism, an imbalance of osteogenic/adipogenic differentiation, and poor vascularization repair. The prevention and treatment of ONFH has always been a great challenge for clinical orthopedic surgeons. However, recent studies have emphasized that the use of mesenchymal stem cells (MSCs) to treat steroid-induced ONFH (SONFH) is a promising therapy. This review focuses on the role and molecular mechanism of epigenetic regulation in the progress of MSCs in the treatment of SONFH, and discusses the significance of the latest research in the treatment of SONFH from the perspective of epigenetics.

BackgroundSchwannomas are benign tumors originating from Schwann cells, frequently occurring in the spinal cord and peripheral nerves. Intraosseous schwannomas, a rare subset, account for approximately 0.2% of schwannomas. Intraosseous schwannomas commonly impinge the mandible, followed by the sacrum and the spine. By far, only three cases of radius intraosseous schwannomas have been reported in PubMed. The tumor was treated differently in all three cases, resulting in different outcomes.Case presentationA 29-year-old male construction engineer who complained of a painless mass on the radial aspect of the right forearm was diagnosed with an intraosseous schwannoma of the radius based on radiography, three-dimensional computed tomography reconstruction, magnetic resonance imaging, pathological examination, and immunohistochemistry. A different surgical approach was employed to reconstruct the radial graft defect using bone microrepair techniques, resulting in more reliable bone healing and early functional recovery. Meanwhile, no clinical and radiographic findings suggestive of recurrence were observed at the 12-month follow-up.ConclusionVascularized bone flap transplantation combined with three-dimensional imaging reconstruction planning might yield better results for repairing small segmental bone defects of the radius caused by intraosseous schwannomas.

Regulation of chromosome condensation 2 (RCC2) is associated with the cell cycle and is a crucial regulator of the chromatin condensation 1 (RCC1) family. The members of this family were normally regulators in the process of DNA replication and nucleocytoplasmic transport. RCC2 overexpression may lead to tumor formation and poor prognosis in some tumors including breast cancer and lung adenocarcinoma. However, the possible role of RCC2 in tumor formation and its prognostic function remains unclear. In this study, expression analysis from databases including The Cancer Genome Atlas (TCGA) and Clinical Proteomic Tumor Analysis Consortium (CPTAC) were combined to perform the first integrative and comprehensive analysis of RCC2 in human pan-cancer. RCC2 was highly expressed in most tumors which may lead to a poor prognosis. RCC2 expression was associated with immune/stromal infiltration, immune checkpoints, tumor mutational burden, and microsatellite instability. Thus, RCC2 could be a novel biomarker for prognosis and a promising cancer therapy target.

Head and neck squamous cell carcinoma (HNSCC) comprise a group of malignant tumors arising from the squamous epithelium of the oral cavity, pharynx, and larynx. HNSCC is the 6th most common cancer in the world, with approximately 650,000 new cases and 400,000 deaths annually. Although survival rates have improved, HNSCC therapy may result in short – or long-term morbidity in approximately 50% of cases. Previous studies have also indicated that the overexpression of procollagen-Lysine, 2-Oxoglutarate 5-Dioxygenases (PLOD) family proteins could lead to certain diseases or even tumors. However, there has been no dedicated evaluation of the relationship between PLOD family members and HNSCC. Here we used data from the Cancer Genome Atlas (TCGA), Genotype-Tissue Expression (GTEx), and Human Protein Atlas (HPA) databases to explore the potential role of PLOD family proteins in HNSCC. Our evaluations suggest that increased expression of PLOD family proteins may be associated with poorer prognosis and increased immune infiltration in HNSCC, making these proteins a potential biomarker for personalized treatment of HNSCC.

Long-time ischemia worsening transplant outcomes in vascularized composite allotransplantation (VCA) is often neglected. Ischemia-reperfusion injury (IRI) is an inevitable event that follows reperfusion after a period of cold static storage. The pathophysiological mechanism activates local inflammation, which is a barrier to allograft long-term immune tolerance. The previous publications have not clearly described the relationship between the tissue damage and ischemia time, nor the rejection grade. In this review, we found that the rejection episodes and rejection grade are usually related to the ischemia time, both in clinical and experimental aspects. Moreover, we summarized the potential therapeutic measures to mitigate the ischemia-reperfusion injury. Compare to static preservation, machine perfusion is a promising method that can keep VCA tissue viability and extend preservation time, which is especially beneficial for the expansion of the donor pool and better MHC-matching.

BackgroundTransverse and oblique deep inferior epigastric artery perforator (DIEP) flaps are widely used in breast, lower extremity, urogenital, head and neck reconstruction. In this report, we present our experience with selecting perforator vessels for transverse and oblique DIEP flaps based on an anatomical study and clinical cases.Materials and methodsA detailed anatomical study of the DIEP flap was carried out using a standardized injection of lead oxide in 10 fresh cadavers. Additionally, 35 male pediatric patients (age 5–12 years) underwent lower extremity reconstruction with a DIEP flap. A transverse DIEP flap was used when the defect template did not exceed zone IV, while an oblique DIEP flap was used when the defect template exceeded zone IV.ResultsPerforators located below the umbilicus in zones I and II were rich in transverse anastomoses across the midline of the abdominal wall, which is the basis for the transverse DIEP flap. Perforators lateral to the umbilicus in zone I had true anastomoses with the musculophrenic artery, the morphological basis for the oblique DIEP flap. The DIEP flap design was transverse in 20 patients and oblique in 15. Flap sizes ranged from 8 × 4.5 cm2 to 24 × 9 cm2. One oblique DIEP flap was necrosed totally, and it was repaired by a latissimus dorsi musculocutaneous flap.ConclusionThe transverse DIEP flap design based on the perforator located below the umbilicus in zone I is recommended for small skin and soft tissue defects. We recommend the use of the oblique DIEP flap design based on the perforator lateral to the umbilicus in zone I as an extended flap to reconstruct large tissue defects.

In the case of a boom in space resource development, space debris will increase dramatically and cause serious problems for the spacecraft in orbit. To address this problem, a novel context sensing-YOLOv5 (CS-YOLOv5) is proposed for small and weak space object detection, which could realize the extraction of local context information and the enhancement and fusion of spatial information. To enhance the expression ability of feature information and the identification ability of the network, we propose the cross-layer context fusion module (CCFM) through multiple branches in parallel to learn the context information of different scales. At the same time, to map the small-scale features sequentially to the features of the previous layer, we design the adaptive weighting module (AWM) to assist the CCFM in further enhancing the expression of features. Additionally, to solve the problem that the spatial information of small objects is easily lost, we designed the spatial information enhancement module (SIEM) to adaptively learn the weak spatial information of small objects that need to be protected. To further enhance the generalization ability of CS-YOLOv5, we propose a contrast mosaic data augmentation to enrich the diversity of the sample. Extensive experiments are conducted on self-built datasets, which strongly prove the effectiveness of our method in space object detection.

Background: Multi-territory perforator flaps are a reconstructive measure for repairing large soft tissue defects caused by tumors or trauma. However, the use of these flaps in clinical practice has been restricted due to the uncertain blood supply. Therefore, promoting the survival of the multi-territory perforator flap is critical for clinical repair and reconstruction. In our study, we explored the effects of melatonin (MLT) on multi-territory perforator flaps and the possible molecular mechanisms.Materials and Methods: Seventy-two Sprague–Dawley rats (250–300 g) were randomly divided into 3 groups (n = 24): Control, MLT and MLT + ML385 groups. First, we assessed the survival area of the flap, followed by the micro-vessel density and CD31-positive vessel expression. Apoptosis of the skin flap under immunofluorescence and expression of the apoptosis-related proteins Bcl-2, Bax and Caspase3 were measured. Additionally, angiogenesis of the skin flaps was shown by angiography, and NRF2 and FUNDC1 mRNA and protein expression was detected by real-time PCR and western blotting.Results: The results showed that MLT increased the survival area of the multi-territory perforator flap, which was related to increased angiogenesis and decreased apoptosis. We also found that mRNA and protein of NRF2 and FUNDC1 levels were significantly increased after MLT treatment, and an NRF2 inhibitor reversed the ability of MLT to enhance multi-territory perforator flap survival, promote angiogenesis and inhibit apoptosis and reduced FUNDC1 protein expression.Conclusion: MLT promoted angiogenesis and inhibited apoptosis to promote the survival of multi-territory perforator flaps, which may be regulated via the NRF2/FUNDC1 axis.

Neural precursor cells (NPCs) tend to aggregate and develop into three-dimensional (3D) spheres, which in turn help maintain the stemness of the cells. This close relationship between spherical environments and cell stemness direct us to assume that 3D spheres of astrocytes (ASTs) may facilitate the acquisition of stem cell-like features and generate sufficient seed cells for the regeneration of neurons. In vitro results confirmed that mouse ASTs cultured on agarose surfaces spontaneously formed cell spheres and exhibited molecular features similar to stem cells, particularly capable of further differentiating into neurons and forming functional synaptic networks with synchronous burst activities. RNA-sequencing results revealed the similarity between AST-derived stem cells (A-iSCs) and NPCs in global gene expression profiles. The potency of A-iSCs in repairing neural injuries was evaluated in a mouse model of middle cerebral artery occlusion. It was observed that the transplanted A-iSCs expressed a series of markers related to neural differentiation, such as NeuN, Tuj1, and Map2, indicating the conversion of the transplanted A-iSCs into neurons in the scenario. We also found that the injured mice injected with A-iSCs exhibited significant improvements in sensorimotor functions after 8 weeks compared with the sham and control mice. Taken together, mouse ASTs form cell spheres on agarose surfaces and acquire stem cell-associated features; meanwhile, the derived A-iSCs possess the capacity to differentiate into neurons and facilitate the regeneration of damaged nerves.

Objective The aim of the present study was to report a novel design of the chimeric deep inferior epigastric artery perforator flap (DIEP) to achieve dead space filling, Achilles tendon bridging, and skin resurfacing simultaneously with minimal donor‐site morbidity. Methods From September 2012 to May 2016, a retrospective study was carried out on six pediatric patients with composite soft tissue defects of the heel that were repaired with the chimeric DIEP flap. The chimeric flap design included a flap of the anterior sheath of the rectus, a block of rectus muscle, and a large skin paddle. All the parts were supplied by a common artery. After harvesting the flap, all element parts were inserted at the corresponding sites in a tension‐free manner. With one set of vessel anastomoses at the recipient site, accurate repair with tendon reconstruction, dead space elimination, and wound covering were accomplished. The donor site incisions were closed initially. Data on patient age, medical history, injury severity, defect size, flap dimensions, recipient vessels, donor site closure, complications, and follow‐up were collected and reviewed. Results Five of the six chimeric DIEP flaps survived without complications. The remaining one case experienced partial necrosis of the skin paddle caused by venous congestion, which healed after routine dressing changes. Primary donor site closure was accomplished in all cases. The mean follow‐up was 18.6 months (range, 10–36 months). Five patients had satisfactory aesthetic and functional outcomes; one patient needed a secondary debulking procedure. Compared to the unaffected side, the affected side showed no obvious difference for ankle movement, tiptoe function, and patient gait during the follow‐up period. Good ankle function was observed in all patients. There was no donor site breakdown, with only a slightly noticeable linear scar. Conclusion The chimeric DIEP flap reduced the operative time, solved the problem of deficiency of recipient vessels, and attained satisfactory functional and aesthetic outcomes with low donor site morbidity. Therefore, it is a promising option for three‐dimensional reconstruction of composite defects with dead space and Achilles tendon defects as well as skin loss in children.

Abstract The success of free vascularized fibular bone graft (FVFBG) has accelerated the osteo reconstruction which results from trauma, resection of a tumor or an infectious bone segment, or correction of congenital deformity. But the complication behind should not be overlooked. The failure could necessitate a second surgery, which prolong the rehabilitation period and produce further health cost. Worst, the patients may suffer a permanent impaired ankle function, or a sustained morpho-functional loss on reconstructive area which are hard to save. To provide an overview of the complication related to reconstruction by FVFBG, a narrative review is conducted to identify the complications including their types and rates, the contributing factors, the approaches to measure and the techniques to avoid. Methodologically, by quick research on Pubmed and abstract reading of reviews, we characterize five reconstructive areas where FVFBG were most frequently applied: extremities, mandible, spine, osteonecrosis of femoral head, and penile. Following, the complications on different reconstructive areas are retrieved, studied and presented in five (or more specifically, six) separate sections. By the way, meaningful difference between FVFBG and other bone flap was presented in a few words if necessary. Donor-site morbidities were studied and summarized as a whole. In these literatures, the evidences documented on limb and mandibular reconstruction have the fullest detail, followed by the spine and lastly the penile. In conclusion, FVFBG, though a mature technique, needs further deep and comprehensive study and maybe device-based assistance to achieve better reconstructive effect and minimize donor-site damage.

BackgroundComplex heel defects constitute a significant challenge for plastic surgeons.ObjectivesIn this study, versatilities of free double skin paddle ALT flaps in the reconstruction of complex soft tissue defects of heels were explored.MethodsFrom January 2010 to December 2019, 16 patients (13 male and 3 females) aged 16–74 years underwent double skin paddle ALT flap reconstruction in our department. All the patients had large defects located at the heel, and 5 had a dead space. Underlying structures such as vessels, bones, and tendons were exposed in all cases.ResultsFlap survival rate was 100% after the reconstruction. Eleven double skin paddle ALT flaps and 5 vastus lateralis muscle-chimeric double skin paddle ALT flaps were used. The size of the skin flap ranged from 9.5 × 4.5 cm2 to 22 × 10 cm2, and the size of a muscle segment ranged from 6 × 3 × 1 cm3 to 10 × 3 × 2 cm3. The mean follow-up was 22.6 months (range: 10–81 months). The wounds healed well, providing reliable soft tissue coverage and good heel contour. All the patients ambulated independently during the follow-up period. Most of them regained protective sensation. The average two-point discrimination was 32.7 mm (range: 27–37 mm).ConclusionDouble skin paddle ALT flaps are a feasible option for the reconstruction of complex heel defects, with good functional and aesthetic results. Nonetheless, further studies comparing double skin paddle ALT flaps to other flap techniques are needed.

Pituitary tumor-transforming gene 1 (PTTG1) encodes a multifunctional protein that is involved in many cellular processes. However, the potential role of PTTG1 in tumor formation and its prognostic function in human pan-cancer is still unknown. The analysis of gene alteration, PTTG1 expression, prognostic function, and PTTG1-related immune analysis in 33 types of tumors was performed based on various databases such as The Cancer Genome Atlas database, the Genotype-Tissue Expression database, and the Human Protein Atlas database. Additionally, PTTG1-related gene enrichment analysis was performed to investigate the potential relationship and possible molecular mechanisms between PTTG1 and tumors. Overexpression of PTTG1 may lead to tumor formation and poor prognosis in various tumors. Consequently, PTTG1 acts as a potential oncogene in most tumors. Additionally, PTTG1 is related to immune infiltration, immune checkpoints, tumor mutational burden, and microsatellite instability. Thus, PTTG1 could be potential biomarker for both prognosis and outcomes of tumor treatment and it could also be a promising target in tumor therapy.

Spinal pain is a major clinical problem. Here the authors show that osteoclasts create porous area of endplates of the vertebrae and sensory innervation of porous endplates by Netrin-1 release from osteoclasts mediates PGE2-induced spinal hypersensitivity in mice.

Abstract Background To investigate the feasibility and clinical efficacy of free vascularized iliac bone flap based on deep iliac circumflex vessels graft for the treatment of osteonecrosis of femoral head (ONFH) in young adults. Methods Eighteen patients (19 hips) undergoing ONFH were included from January 2016 to May 2017. After the debridement of the necrotic bones, the contralateral vascularized iliac bone flap was designed and harvested before grafting, in which the deep circumflex iliac vessels and the transverse branch (or ascending branch) of the lateral circumflex femoral artery and their accompanying veins were anastomosed. X-ray was obtained at 1, 3, 6, 9, and 12 months respectively for evaluation of the bone flap healing. Hip function was evaluated with Harris hip score at 18 months postoperatively. Results None of the patients is lost to follow-up. All the hips healed well except for four complications: one patient developed superficial wound infection, one patient had subcutaneous hematoma, and two patients developed anterolateral femoral cutaneous nerve injury. X-ray films at 12 months showed improvement in 13 hips (68.4%), five hips (26.3%) were unchanged, and one femoral head collapse with conversion to total hip arthroplasty (THA) at 14 months postoperatively (5.3%). Postoperative mean Harris hip scores were significantly improved compared to the preoperative results (P

Mammalian spermatogenesis is a highly ordered process that is determined by chromatin-associated moderators which still remain poorly understood. Through a multi-control group proteomics strategy, we confirmed that Sugp2 was a chromatin-associated candidate protein, and its signal arose along spermatogenesis. The expression results showed that Sugp2, which is mainly expressed in the testis, had two transcripts, encoding one protein. During spermatogenesis, Sugp2 was enriched in the nucleus of male germ cells. With the depletion of Sugp2 by CRISPER-Cas9 technology, we found that Sugp2 controlled a network of genes on metal ion and ATP binding, suggesting that alternative splicing regulation by Sugp2 is involved in cellular ion and energy metabolism during spermatogenesis, while it had a little effect on meiotic progression and male fertility. Collectively, these data demonstrated that, as a chromatin-associated protein, Sugp2 mediated the alternative splicing regulatory network during spermatogenesis.

Background: The principle of early flap reconstruction for high-grade traumatic lower-extremity injuries established in 1986 by Godina has been widely accepted. However, the lack of an orthoplastic center in China makes early reconstruction not accessible for all patients with a Gustilo IIIB fracture. This study aimed to analyze the impact of timing on outcomes in lower-extremity traumatic free-flap reconstruction. Methods: A retrospective review identified 394 free-flap reconstructions performed from January 2005 to January 2020 for Gustilo IIIB tibial fractures. Patients were stratified based on the number of debridements: two times or less (early) and more than two times (delayed). The interval between injury and reconstruction, surgery time, hemorrhage volume, length of hospitalization (LoS), wound and bone healing time, flap outcomes, and function restoration were examined based on times of debridement. Results: The mean interval between injury and flap reconstruction in the early-repair group with 6.15 ± 1.82 postoperative days (PODs) was significantly shorter than that of the delayed-repair group with 16.46 ± 4.09 PODs (p < 0.001). The flap harvest time, reconstructive time, and intraoperative blood loss were also significantly less in the early-repair group compared to the delayed-repair group. Interestingly, we observed an 8.20% enlargement of wound size due to multiple debridements in the delayed-repair group. Most importantly, the early-repair group had better outcomes with a decreased risk of total or partial flap necrosis, lower incidence of flap complications, and fewer overall late complications than the delayed-repair group. In addition, the LoS, as well as wound and bone healing time, were notably shorter in the early-repair group. Furthermore, 4.85% of cases in the delayed-repair group experienced additional operations on bone, while no additional operations were performed in the early-repair group. All cases in both groups obtained satisfying functional results, while the early-repair group showed better functional recovery. Conclusions: Early repair with free flaps performed within two instances of debridement had superior outcomes when compared with delayed reconstruction after multiple debridements, consistent with Godina’s findings. We recommended early referral to a higher-level hospital with orthoplastic capabilities after an aggressive and thorough initial debridement carried out by senior surgeons.

In the physiological condition, the skeletal system’s bone resorption and formation are in dynamic balance, called bone homeostasis. However, bone homeostasis is destroyed under pathological conditions, leading to the occurrence of bone metabolism diseases. The expression of hypoxia-inducible factor-1α (HIF-1α) is regulated by oxygen concentration. It affects energy metabolism, which plays a vital role in preventing bone metabolic diseases. This review focuses on the HIF-1α pathway and describes in detail the possible mechanism of its involvement in the regulation of bone homeostasis and angiogenesis, as well as the current experimental studies on the use of HIF-1α in the prevention of bone metabolic diseases. HIF-1α/RANKL/Notch1 pathway bidirectionally regulates the differentiation of macrophages into osteoclasts under different conditions. In addition, HIF-1α is also regulated by many factors, including hypoxia, cofactor activity, non-coding RNA, trace elements, etc. As a pivotal pathway for coupling angiogenesis and osteogenesis, HIF-1α has been widely studied in bone metabolic diseases such as bone defect, osteoporosis, osteonecrosis of the femoral head, fracture, and nonunion. The wide application of biomaterials in bone metabolism also provides a reasonable basis for the experimental study of HIF-1α in preventing bone metabolic diseases.

Backgrounds: The purpose of this study is to present our clinical experience using the Ilizarov bone transfer technique and free-flap technique in the reconstruction of large tibial bone and soft tissue defects, including an evaluation of both the management of postoperative complications and long-term outcomes. Methods: From January 2010 to May 2020, 72 patients with tibia bone and soft tissue defects were retrospectively evaluated. Either an anterolateral thigh perforator flaps (ALTP) or latissimus dorsi musculocutaneous flaps (LD), solely or in combination, were used to cover soft tissue defects. Once the flap was stabilized, an Ilizarov external fixator was applied to the limb. Follow-up was postoperatively performed at 1, 3, 6, 9, and 12 months. Results: Postoperatively, there were two cases of total and five of partial flap necrosis, and two cases of subcutaneous ulcers, which were caused by vascular crisis, infection, and hematoma, respectively. All the patients underwent Ilizarov external fixator surgery after flap recovery. A total of 16 complications occurred, including 3 cases of simple needle tract infection (antibiotic treatment) and 13 cases of complications requiring reoperation. A correlation factor analysis revealed that the main factors affecting the healing time were the defect length and operative complications. All patients with complications treated with the vascularized iliac flap eventually healed completely. Conclusions: The Ilizarov method used together with an ALTP, LD, or a combination thereof yields good clinical results for repairing large bone and soft tissue defects of the tibia, thus reducing the incidence of amputations. However, longer treatment times may be involved, and postoperative complications can occur. The vascularized iliac flap may be a suitable choice for the treatment of postoperative complications of this type of Ilizarov bone transport.

Background: Reconstruction of the large soft-tissue defects in the lower extremity still constitutes a challenge for plastic surgeons. This retrospective study was conducted to compare the surgical and clinical outcomes of the chain-linked bilateral anterolateral thigh perforator flaps and extended latissimus dorsi musculocutaneous flap in the reconstruction of the large soft tissue defects of the lower extremity. Methods: From January 2012 to December 2021, 34 patients aged between 20 and 66 years received chain-linked bilateral anterolateral thigh perforator flaps (15 cases) or extended latissimus dorsi musculocutaneous flaps (19 cases) for the reconstruction of extensive soft-tissue defects in the lower extremity. The two groups were homogeneous in terms of age, etiology, comorbidities, and flap area. In addition, the intraoperative data, outcomes, complications, and long-term follow-up results were collected and analyzed. Results: The extended latissimus dorsi musculocutaneous flap group had a shorter operation time (271.8 ± 59.5 min vs. 429.6 ± 51.9 min), harvest time (58.9 ± 24.8 min vs. 152.7 ± 41.4 min), and anastomosis time (27.2 ± 10.4 min vs. 53.7 ± 8.1 min) than the chain-linked bilateral anterolateral thigh perforator flaps group (p < 0.05). Based on patient self-assessment, the donor site temporary muscle weakness in the extended latissimus dorsi musculocutaneous flap group was significantly more than that in the chain-linked bilateral anterolateral thigh perforator flaps group (p < 0.05). Conclusion: Both methods can repair large defects and restore the function of the injured limbs at a single stage. However, considering the operation time and flap-harvesting time, the authors recommend the extended latissimus dorsi musculocutaneous flap, especially for those who cannot tolerate a prolonged surgery.

Abstract: A 37-year-old man complained of a refractory posterior malleolar ulceration on his left ankle. He was diagnosed with Werner syndrome according to the progeroid clinical features and genetic testing. To approach the ulceration, a free flow-through right anterolateral thigh perforator flap with anterolateral thigh cutaneous nerve was harvested. One year later, he was readmitted due to a new ulceration on his right ankle. We harvested the left anterolateral thigh perforator flap with anterolateral thigh cutaneous nerve to reconstruct the defect. After one more year of follow-up, there was no recurrence of ulcers, and the sensation of the flap recovered partially after 6 months. We conclude that free flow-through anterolateral thigh perforator flap is a feasible choice for the repair of foot ulcers in Werner syndrome.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Polyoxometalates based ionic liquids (POM-ILs) exhibit a high catalytic activity in oxidative desulfurization. In this paper, four new POM-IL hybrids based on transition metal mono-substituted Keggin-type phosphomolybdates, [Bmim]5[PMo11M(H2O)O39] (Bmim = 1-butyl 3-methyl imidazolium; M = Co2+, Ni2+, Zn2+, and Mn2+), have been synthesized and used as catalysts for the oxidation/extractive desulfurization of model oil, in which ILs are used as the extraction solvent and H2O2 as an oxidant under very mild conditions. The factors that affected the desulfurization efficiency were studied and the optimal reaction conditions were obtained. The results showed that the [Bmim]5[PMo11Co(H2O)O39] catalyst demonstrated the best catalytic activity, with sulfur-removal of 99.8%, 85%, and 63% for dibenzothiophene (DBT), 4,6-dimethyldibenzothiophene (4,6-DMDBT), and benzothiophene (BT), respectively, in the case of extraction combining with a oxidative desulfurization system under optimal reaction conditions (5 mL model oil (S content 500 ppm), n(catalyst) = 4 μmol, n(H2O2)/n(Substrate) = 5, T = 50 °C for 60 min with [Omim]BF4 (1 mL) as the extractant). The catalyst can be recycled at least 8 times, and still has stability and high catalytic activity for consecutive desulfurization. Probable reaction mechanisms have been proposed for catalytic oxidative/extractive desulfurization.

Localized corrosion is a serious, hazardous destroyer of steel petroleum pipelines meant for long-time use. However, previous studies on localized corrosion primarily focused on local corrosion morphology and corrosion rate of bulk metals because detecting the corrosion state of occlusive metals is difficult. Herein, we employ a simulating occluded battery unit to disclose the local corrosion behavior of the steel petroleum pipeline (N80 steel) in an occlusive S2--enriched solution. After simulating localized corrosion in the S2- containing corrosion solution using the occluded battery unit, the occlusive solution was acidified and the migration amount of S2- to the occluded area increased. Despite the increase of S2- concentration, the addition of quinoline corrosion inhibitor (0.8 wt%) still effectively impedes the corrosion of the occluded metal. Moderately raising the environmental temperature can stimulate the activity of the inhibitor and promote the inhibition effect. The quinoline corrosion inhibitor displays the maximum inhibition rate at an elevated temperature of 50°C. Meanwhile, a maximum over the temperature of 60°C-70°C will likely accelerate the failure of the inhibitor. [ABSTRACT FROM AUTHOR]

Long-time ischemia worsening transplant outcomes in vascularized composite allotransplantation (VCA) is often neglected. Ischemia-reperfusion injury (IRI) is an inevitable event that follows reperfusion after a period of cold static storage. The pathophysiological mechanismactivates local inflammation, which is a barrier to allograft long-term immune tolerance. The previous publications have not clearly described the relationship between the tissue damage and ischemia time, nor the rejection grade. In this review, we found that the rejection episodes and rejection grade are usually related to the ischemia time, both in clinical and experimental aspects. Moreover, we summarized the potential therapeutic measures to mitigate the ischemia-reperfusion injury. Compare to static preservation, machine perfusion is a promising method that can keep VCA tissue viability and extend preservation time, which is especially beneficial for the expansion of the donor pool and better MHC-matching. [ABSTRACT FROM AUTHOR]

The sensory nerve was recently identified as being involved in regulation of bone mass accrual. We previously discovered that prostaglandin E2 (PGE2) secreted by osteoblasts could activate sensory nerve EP4 receptor to promote bone formation by inhibiting sympathetic activity. However, the fundamental units of bone formation are active osteoblasts, which originate from mesenchymal stromal/stem cells (MSCs). Here, we found that after sensory denervation, knockout of the EP4 receptor in sensory nerves, or knockout of COX-2 in osteoblasts, could significantly promote adipogenesis and inhibit osteogenesis in adult mice. Furthermore, injection of SW033291 (a small molecule that locally increases the PGE2 level) or propranolol (a beta blocker) significantly promoted osteogenesis and inhibited adipogenesis. This effect of SW033291, but not propranolol, was abolished in conditional EP4-KO mice under normal conditions or in the bone repair process. We conclude that the PGE2/EP4 sensory nerve axis could regulate MSC differentiation in bone marrow of adult mice. [ABSTRACT FROM AUTHOR]