Exploring Cr and molten salt interfacial interactions for molten salt applications.

Molten salts play an important role in various energy-related applications such as high-temperature heat transfer fluids and reaction media. However, the extreme molten salt environment causes the degradation of materials, raising safety and sustainability challenges. A fundamental understanding of material-molten salt interfacial evolution is needed. This work studies the transformation of metallic Cr in molten 50/50 mol% KCl-MgCl2via multi-modal in situ synchrotron X-ray nano-tomography, diffraction and spectroscopy combined with density functional theory (DFT) and ab initio molecular dynamics (AIMD) simulations. Notably, in addition to the dissolution of Cr in the molten salt to form porous structures, a δ-A15 Cr phase was found to gradually form as a result of the metal-salt interaction. This phase change of Cr is associated with a change in the coordination environment of Cr at the interface. DFT and AIMD simulations provide a basis for understanding the enhanced stability of δ-A15 Cr vs. bcc Cr, by revealing their competitive phase thermodynamics at elevated temperatures and probing the interfacial behavior of the molten salt at relevant facets. This study provides critical insights into the morphological and chemical evolution of metal-molten salt interfaces. The combination of multimodal synchrotron analysis and atomic simulation also offers an opportunity to explore a broader range of systems critical to energy applications.

In situ synchrotron X-ray total scattering measurements and analysis of colloidal CsPbX3 nanocrystals during flow synthesis.

In situ X-ray scattering measurements of CsPbX3 (X = Cl, Br, I) nanocrystal formation and halide exchange at NSLS-II beamlines were performed in an automated flow reactor. Total scattering measurements were performed at the 28-ID-2 (XPD) beamline and small-angle X-ray scattering at the 16-ID (LiX) beamline. Nanocrystal structural parameters of interest, including size, size distribution and atomic structure, were extracted from modeling the total scattering data. The results highlight the potential of these beamlines and the measurement protocols described in this study for studying dynamic processes of colloidal nanocrystal synthesis in solution with timescales on the order of seconds.

Preliminary Prospective Preoperative and Postoperative Evaluation of Median Nerve Stiffness by Using Sonoelastography.

ABSTRACT: Carpal tunnel syndrome is the most common peripheral nerve entrapment syndrome. No previous studies have compared preoperative and follow-up sonoelastography results or investigated the correlation of median nerve stiffness with the subjective/objective outcomes. Therefore, the aim of this study was to compare the preoperative and postoperative elastography after carpal tunnel release and find the correlation with associated subjective/objective outcomes.From May 2017 to March 2020, 32 patients (6 males, 26 females; 34 hands) with carpal tunnel syndrome were enrolled in this prospective study. Demographic data, QuickDASH score (Chinese version), Boston Carpal Tunnel Questionnaire (Chinese version), nerve conduction velocity/electromyography, and median nerve stiffness by sonoelastography were recorded.Comparisons of preoperative and average sonoelastography findings 1.5 years postoperatively showed a significant decrease in stiffness presented by velocity (Vs) (preoperative Vs, 4.63 ± 1.27 m/s, vs postoperative Vs, 3.39 ± 0.59 m/s; P < 0.001). Changes in subjective functional outcomes also showed the same significant trend. Based on the neurophysiologic study, the improvement of nerve conduction study and elastography have the significant correlation.The same trend of preoperative and postoperative changes in median nerve stiffness and subjective questionnaires/objective neurophysiologic studies may imply that sonoelastography can be used to assess the response to surgery in patients with carpal tunnel syndrome.

Automated Age-Related Macular Degeneration Detector on Optical Coherence Tomography Images Using Slice-Sum Local Binary Patterns and Support Vector Machine.

Artificial intelligence has revolutionised smart medicine, resulting in enhanced medical care. This study presents an automated detector chip for age-related macular degeneration (AMD) using a support vector machine (SVM) and three-dimensional (3D) optical coherence tomography (OCT) volume. The aim is to assist ophthalmologists by reducing the time-consuming AMD medical examination. Using the property of 3D OCT volume, a modified feature vector connected method called slice-sum is proposed, reducing computational complexity while maintaining high detection accuracy. Compared to previous methods, this method significantly reduces computational complexity by at least a hundredfold. Image adjustment and noise removal steps are excluded for classification accuracy, and the feature extraction algorithm of local binary patterns is determined based on hardware consumption considerations. Through optimisation of the feature vector connection method after feature extraction, the computational complexity of SVM detection is significantly reduced, making it applicable to similar 3D datasets. Additionally, the design supports model replacement, allowing users to train and update classification models as needed. Using TSMC 40 nm CMOS technology, the proposed detector achieves a core area of 0.12 mm2 while demonstrating a classification throughput of 8.87 decisions/s at a maximum operating frequency of 454.54 MHz. The detector achieves a final testing classification accuracy of 92.31%.

Perfusion Dynamics during Secondary Flap Debulking with Liposuction.

BACKGROUND: Lower extremity trauma often necessitates reconstruction with flap transfer. One of the reconstructive goals is a thin soft tissue coverage with appropriate contour. Therefore, a secondary debulking of the flap is usually performed. METHODS: Debulking through conventional lipectomy is compared with liposuction followed by excision of the defatted flap excess. Demographic data, surgical details, and postoperative outcomes are compared and analyzed. The perfusion dynamics of the flaps undergoing liposuction debulking are studied by means of perioperative indocyanine green fluorescence angiography, as well as postoperative laser Doppler imaging. RESULTS: Patients undergoing lipectomy (n = 69; 57.5%) or liposuction (n = 51; 42.5%) debulking had a similar rate of postoperative complications. Partial necrosis was observed in 7.2% (lipectomy) versus 7.8% (liposuction) of flaps. Fluorescence angiography showed a substantial decrease in flap perfusion following the infiltration with an epinephrine-containing tumescent solution (74.3% ± 8.2% prior to infiltration versus 16.8% ± 7.1% after infiltration; p < 0.001), resulting in a dark flap appearance. Laser Doppler imaging confirmed the hypoperfusion on postoperative day 1. CONCLUSION: Secondary debulking of a lower extremity flap can be safely and efficiently performed through liposuction combined with peripheral excision of the defatted flap in a single stage. Perfusion studies may show a misleading hypoperfusion of the defatted flap, which does not accurately predict subsequent necrosis or complications.

Evaluating Resource Utilization with Free or Pedicled Perforator Flaps in Distal Leg Reconstruction.

BACKGROUND: The decision between local and free tissue coverage for distal lower leg defects has long been dictated by the location and size of defects. Recent reports of distal defects treated successfully with pedicled perforator flaps demonstrate equivalent clinical outcomes; however, the complication rate can be high. The goal of this study was to evaluate the cost equivalence of free versus pedicled perforator flap to assist decision-making and guide clinical care. METHODS: The institutional database was searched for patients with acute injury over the distal lower extremity requiring free or pedicled perforator flap. Demographic, clinical, and total resource cost was gathered. Patients were matched to Gustilo-Anderson or Arbeitsgemeinschaft fur Osteosynthesefragen classification as well as size of defect and outcomes, and cost compared. RESULTS: We have included 108 free flaps and 22 pedicled perforator flaps in the study. There was no difference in complication rate between groups. Free flaps had significantly more reoperations, required longer operative time, and had longer intensive care unit (ICU) care with higher cost of surgery and overall cost than pedicled flaps. When controlling for size of defect, surgical cost remained significantly different between groups (p = 0.013), but overall cost did not. Multivariable regression analysis indicated flap type to be the primary driver of cost of surgery, while body mass index elevated the total cost. CONCLUSION: Pedicled perforator flap coverage for small to medium-sized defects (< 70 cm2) is a viable and cost-effective option for distal lower leg soft tissue reconstruction after acute traumatic injury with similar clinical outcomes and shorter operative duration and ICU stay.

Heterotopic Digital Replantation in Mutilating Hand Injuries: An Algorithmic Approach Based on 53 Cases and Literature Review.

BACKGROUND: Reconstruction of the mutilated hand is one of the most difficult challenges for hand microsurgeons. When multiple digits are amputated, orthotopic digital replantation of the available remnants may not adequately restore the hand function. In such cases, heterotopic digital replantation may provide a more functional reconstruction. METHODS: Between 1997 and 2018, 53 patients with mutilating hand injuries were treated with heterotopic digital replantation at our institution. A retrospective chart review was conducted to determine the details of the injury, indications for heterotopic digital replantation, and functional outcomes. RESULTS: In total, 173 digits were amputated from 53 patients (one patient suffered from bilateral hand injuries, so totally 54 hands). Sixty-eight digits underwent heterotopic digital replantation, 30 digits had orthotopic digital replantation, and 75 stumps were terminalized. The survival rate of digits treated by heterotopic digital replantation and orthotopic digital replantation was 83.8% (57/68) and 86.7% (26/30), respectively (p = 1). Tripod grip was achieved in 83.3% (45/54) of patients following replantation and optional secondary reconstructive surgeries. CONCLUSION: Heterotopic digital replantation is a practical and reliable method for achieving optimal hand function following mutilating hand injuries. The basic principles are to restore a functional thumb in the first instance, followed by at least two adjacent fingers against which the thumb can oppose. This method is particularly indicated when orthotopic digital replantation of the available amputated parts would yield a suboptimal result.

Comparison of the clinical outcomes between vascularized bone graft and the Masquelet technique for the reconstruction of Gustilo type III open tibial fractures.

BACKGROUND: Gustilo type III tibial fractures commonly involve extensive soft tissue and bony defects, requiring complex reconstructive operations. Although several methods have been proposed, no research has elucidated the efficacies and differences between vascular bone graft (VBG) and the Masquelet technique (MT) to date. We aimed to evaluate and compare the clinical effectiveness of VBG and the MT for the reconstruction of Gustilo type III tibial fractures. METHODS: This retrospective cohort study enrolled patients who underwent reconstruction for Gustilo type III tibial fractures using VBG or the MT in a single center from January 2000 to December 2020. The patients' demographics, injury characteristics, and surgical interventions were documented for analysis. The clinical outcomes including union status, time to union, postoperative infections, and the causes of union failure were compared between the two groups. RESULTS: We enrolled 44 patients: 27 patients underwent VBG, and 17 underwent MT. The average union time was 20.5 ± 15.4 and 15.1 ± 9.0 months in the VBG and MT groups, respectively (p = 0.232). The postoperative deep infection rates were 70.4% and 47.1% in the VBG and MT groups (p = 0.122), respectively. Though not statistically significant, the VBG group had a shorter union time than did the MT group when the bone defect length was > 60 mm (21.0 ± 17.0 versus 23.8 ± 9.4 months, p = 0.729), while the MT group had a shorter union time than did the VBG group when the bone defect was length < 60 mm (17.2 ± 5.6 versus 10.7 ± 4.7 months, p = 0.067). CONCLUSIONS: VBG and MT are both promising reconstruction methods for Gustilo type III tibial fractures. VBG appears to have more potential in reconstructing larger bone defects, while MT may play an important role in smaller bone defects, severe surgical site infections, and osteomyelitis. Therefore, flexible treatment strategies are required for good outcomes in Gustilo type III open tibial fractures.

Popliteal Artery Injury After Fracture and/or Dislocation of the Knee: Risk Stratification for Revascularization Outcome.

BACKGROUND: Managing complex knee trauma involving both vascular and osseous injuries is challenging, yet the available guidelines for efficient popliteal artery injury management after high-velocity blunt knee trauma remain conflicting and inconsistent. In this study, the authors aim to identify the risk factors associated with delayed limb amputation and ischemic muscular sequela postrevascularization. Furthermore, we propose a treatment algorithm to improve the limb salvage rate. METHODS: Patients who presented with traumatic popliteal artery injury resulting in vessel occlusion or rupture, followed by fracture and/or dislocation of the knee from January 2008 to December 2013, were included for retrospective review. RESULTS: Overall delayed amputation rate was 24% (7/29) and 16% (4/25) after successful revascularization. Mangled Extremity Severity Score is higher in the delayed amputation group than the limb-salvaged group (P = 0.02). Higher-impact force (P = 0.03), ischemic limb on presentation (P = 0.03), prolonged ischemia time (P = 0.04), unstable hemodynamics (P = 0.01), longer operation time (P = 0.04), and prolonged intensive care unit stay (P = 0.03) are risk factors of delayed amputation. Longer ischemia time (P = 0.04) and length of popliteal artery injury (P = 0.02) are associated with ischemic muscular sequela. CONCLUSIONS: Mangled Extremity Severity Score is a reliable predictor of limb salvage. An algorithmic approach may improve the outcome of popliteal artery injury after high-velocity blunt knee trauma.

The Effect of Narrow-Band Ultraviolet B Irradiation on the Vascularized Composite Allotransplantation Rat Model.

INTRODUCTION: Vascularized composite allotransplantation (VCA) allows functional and esthetic reconstruction for patients with complex anatomical defects. However, acute and chronic graft rejections are significant obstacles to VCA. Ultraviolet light is an oncogenic environmental hazard. However, ultraviolet B (UVB) has an immunomodulation effect. Therefore, this study aims to elucidate the impact of UVB irradiation on the VCA rat model. METHODS: The rat vascularized bone marrow allotransplantation model was used. A vascularized bone marrow from a Brown Norway rat (RT1Ac) was transplanted into a Lewis rat (RT1Ab). The allograft and surrounding abdominal skin were exposed to narrow-band ultraviolet B (NB-UVB) (311 nm) radiation with an energy of 1350 mJ/cm2 3 times a week until the end of the study period. There were 5 study groups: syngeneic transplantation (group 1), allogeneic transplantation (group 2), allogenic transplantation-NB-UVB (group 3), allogenic transplantation-antilymphocyte serum (ALS)-tacrolimus (group 4), and allogenic transplantation-antilymphocyte serum-tacrolimus-NB-UVB (group 5). RESULTS: Group 5 had decreased graft survival compared with group 4. In the donor cell chimerism analysis, donor cell chimerism decreased significantly after UVB irradiation and was unresponsive to the administered immunosuppressants. After UVB irradiation, the CD8 T-cell ratio was increased, and the regulatory T-cell ratio was decreased. CONCLUSIONS: The preliminary data showed that NB-UVB irradiation of the VCA rat model may decrease graft survival. However, further studies are needed to elucidate the possible mechanisms of this phenomenon.

Vision-Based Learning from Demonstration System for Robot Arms.

Robotic arms have been widely used in various industries and have the advantages of cost savings, high productivity, and efficiency. Although robotic arms are good at increasing efficiency in repetitive tasks, they still need to be re-programmed and optimized when new tasks are to be deployed, resulting in detrimental downtime and high cost. It is therefore the objective of this paper to present a learning from demonstration (LfD) robotic system to provide a more intuitive way for robots to efficiently perform tasks through learning from human demonstration on the basis of two major components: understanding through human demonstration and reproduction by robot arm. To understand human demonstration, we propose a vision-based spatial-temporal action detection method to detect human actions that focuses on meticulous hand movement in real time to establish an action base. An object trajectory inductive method is then proposed to obtain a key path for objects manipulated by the human through multiple demonstrations. In robot reproduction, we integrate the sequence of actions in the action base and the key path derived by the object trajectory inductive method for motion planning to reproduce the task demonstrated by the human user. Because of the capability of learning from demonstration, the robot can reproduce the tasks that the human demonstrated with the help of vision sensors in unseen contexts.

Implantable Immunosuppressant Delivery to Prevent Rejection in Transplantation.

An innovative immunosuppressant with a minimally invasive delivery system has emerged in the biomedical field. The application of biodegradable and biocompatible polymer forms, such as hydrogels, scaffolds, microspheres, and nanoparticles, in transplant recipients to control the release of immunosuppressants can minimize the risk of developing unfavorable conditions. In this review, we summarized several studies that have used implantable immunosuppressant delivery to release therapeutic agents to prolong allograft survival. We also compared their applications, efficacy, efficiency, and safety/side effects with conventional therapeutic-agent administration. Finally, challenges and the future prospective were discussed. Collectively, this review will help relevant readers understand the different approaches to prevent transplant rejection in a new era of therapeutic agent delivery.

Neuromyelitis Optica Spectrum Disorder: From Basic Research to Clinical Perspectives.

Neuromyelitis optica spectrum disorder (NMOSD) is an inflammatory disease of the central nervous system characterized by relapses and autoimmunity caused by antibodies against the astrocyte water channel protein aquaporin-4. Over the past decade, there have been significant advances in the biologic knowledge of NMOSD, which resulted in the IDENTIFICATION of variable disease phenotypes, biomarkers, and complex inflammatory cascades involved in disease pathogenesis. Ongoing clinical trials are looking at new treatments targeting NMOSD relapses. This review aims to provide an update on recent studies regarding issues related to NMOSD, including the pathophysiology of the disease, the potential use of serum and cerebrospinal fluid cytokines as disease biomarkers, the clinical utilization of ocular coherence tomography, and the comparison of different animal models of NMOSD.

A 19-Year Experience With Clavicular Defects: An Algorithm for Flap Selection and Surgical Outcomes.

BACKGROUND: The clavicle contributes to the stability and functional integrity of the shoulder. Clavicle bone defects are uncommon, and the strategy for their management is variable. METHOD: Six patients presented with clavicle bone defects. The causes were as follows: traumatic defects (2 patients), electric injury (1 patient), osteoradionecrosis (2 patients), and nonunion (1 patient). One patient had upper limb palsy for 40 years, and another had posttraumatic shoulder function impairment. A pedicled pectoralis major myocutaneous flap was used for the patient with a dysfunctional limb, and 5 bone flaps (3 free fibular flaps, 1 free iliac flap, and 1 pedicled rib flap) were used for reconstruction in the other patients. RESULT: All flaps (2 pedicled flaps and 4 free flaps) were successfully used for wound repair; the pedicled rib flap demonstrated partial marginal necrosis, and the free fibular flap required reexploration for venous kinking. Five functionally impaired upper limbs showed functional improvements postoperatively. CONCLUSION: For functionless composite clavicles and soft tissue defects, a soft tissue flap will be required for wound repair. A bone flap, especially a fibular flap, is required for the upper limb to show functional recovery. The variety of flaps will be planned according to the defect size comparison between the bone and soft tissue, and ipsilateral upper limb function, and a proposed algorithm will be discussed.

Sonoelastography in the Diagnosis of Carpal Tunnel Syndrome: A Systematic Review of Diagnostic Values Compared With the Normative Population.

BACKGROUND: Sonoelastography (SEL) is widely used for assessing tissue stiffness and pathophysiology. It has also been used to diagnose carpal tunnel syndrome (CTS). However, the current criteria to diagnose CTS in SEL are diverse. The aim of this study was to systematically review the literature and assess the diagnostic value of SEL for CTS. METHODS: A literature review was performed using MEDLINE (PubMed), EMBASE, and the Cochrane Collaboration Library for primary research articles using the keywords sonoelastography and carpal tunnel syndrome. Data related to diagnostic and cutoff value were extracted. Bias assessment was performed. RESULTS: A total of 121 publications were reviewed. Nineteen primary case series met the inclusion criteria and were selected for full analysis. Different diagnostic approaches were identified, with units/expressions including kilopascals, conduct velocity, and strain ratio. The kilopascals and conduct velocity were measured using shear wave elastography, whereas strain ratio was calculated by relative compression quantification. A mean shear modulus cutoff value from 38.25 to 86 kPa and an acoustic radiation force impulse cutoff value of 3.0 to 3.23 m/s were used to diagnose CTS. Eight articles reported strain ratio between the median nerve and nearby tissues with diverse results due to different reference points. The other 3 additional diagnostic values were reported. CONCLUSIONS: Sonoelastography is a useful noninvasive and promising modality to diagnose CTS. It may reflect both the condition of soft tissue scarring and quantitative values for CTS and median nerve stiffness. A diversity of examination values was found in different modalities. A high level of evidence was absent.

End-to-Side Anterior Interosseous Nerve Transfer: A Valuable Alternative for Traumatic High Ulnar Nerve Palsy.

BACKGROUND: The prognosis of high ulnar nerve injury is poor despite nerve repair or grafting. Anterior interosseous nerve (AIN) transfers provide a satisfactory recovery. However, the efficacy of end-to-side (ETS) AIN transfer and optimal timing in Sunderland grade IV/V of high ulnar nerve injury is lacking. OBJECTIVE: The goals were to compare the outcomes of high ulnar nerve injury managed with ETS AIN transfers with those managed with conventional procedures (nerve repair or graft only) and identify differences between early and delayed transfers. METHODS: Patients with isolated high ulnar nerve injury (Sunderland grade IV/V) from 2010 to 2017 were recruited. Patients with conventional treatments and AIN transfers were designated as the control and AIN groups, respectively. Early transfer was defined as the AIN transfer performed within 8 weeks postinjury. Outcomes were measured and analyzed by the British Medical Research Council (BMRC) score, grip strength, and pinch strength. RESULTS: A total of 24 patients with high ulnar nerve injury (Sunderland grade IV/V) were included. There were 11 and 13 patients in the control and AIN groups, respectively. In univariate analysis, both early and delayed AIN transfers demonstrated significantly better motor recovery among BMRC score and strength of grip and pinch at 12 months (P < 0.05). No statistical significance was found between early and delayed transfer. In multivariate analysis, both early and delayed transfers were regarded as strong and independent factors for motor recovery of ulnar nerve. Compared with the control, early [odds ratio (OR), 1.83; P < 0.001] and delayed (OR, 1.59; P < 0.001) transfers showed significant improvement with regard to BMRC scores. The pinch strength in early (OR, 31.68; P < 0.001) and delayed (OR, 26.45; P < 0.001) transfers was also significantly better. CONCLUSION: The ETS AIN transfer, in either early or delayed fashion, significantly improved intrinsic motor recovery in high ulnar nerve injuries classified as Sunderland grade IV/V. The early transfer group demonstrated a trend toward better functional recovery with less downtime.

Automatic Polyp Segmentation in Colonoscopy Images Using a Modified Deep Convolutional Encoder-Decoder Architecture.

Colorectal cancer has become the third most commonly diagnosed form of cancer, and has the second highest fatality rate of cancers worldwide. Currently, optical colonoscopy is the preferred tool of choice for the diagnosis of polyps and to avert colorectal cancer. Colon screening is time-consuming and highly operator dependent. In view of this, a computer-aided diagnosis (CAD) method needs to be developed for the automatic segmentation of polyps in colonoscopy images. This paper proposes a modified SegNet Visual Geometry Group-19 (VGG-19), a form of convolutional neural network, as a CAD method for polyp segmentation. The modifications include skip connections, 5 × 5 convolutional filters, and the concatenation of four dilated convolutions applied in parallel form. The CVC-ClinicDB, CVC-ColonDB, and ETIS-LaribPolypDB databases were used to evaluate the model, and it was found that our proposed polyp segmentation model achieved an accuracy, sensitivity, specificity, precision, mean intersection over union, and dice coefficient of 96.06%, 94.55%, 97.56%, 97.48%, 92.3%, and 95.99%, respectively. These results indicate that our model performs as well as or better than previous schemes in the literature. We believe that this study will offer benefits in terms of the future development of CAD tools for polyp segmentation for colorectal cancer diagnosis and management. In the future, we intend to embed our proposed network into a medical capsule robot for practical usage and try it in a hospital setting with clinicians.

Human Motion Tracking Using 3D Image Features with a Long Short-Term Memory Mechanism Model-An Example of Forward Reaching.

Human motion tracking is widely applied to rehabilitation tasks, and inertial measurement unit (IMU) sensors are a well-known approach for recording motion behavior. IMU sensors can provide accurate information regarding three-dimensional (3D) human motion. However, IMU sensors must be attached to the body, which can be inconvenient or uncomfortable for users. To alleviate this issue, a visual-based tracking system from two-dimensional (2D) RGB images has been studied extensively in recent years and proven to have a suitable performance for human motion tracking. However, the 2D image system has its limitations. Specifically, human motion consists of spatial changes, and the 3D motion features predicted from the 2D images have limitations. In this study, we propose a deep learning (DL) human motion tracking technology using 3D image features with a deep bidirectional long short-term memory (DBLSTM) mechanism model. The experimental results show that, compared with the traditional 2D image system, the proposed system provides improved human motion tracking ability with RMSE in acceleration less than 0.5 (m/s2) X, Y, and Z directions. These findings suggest that the proposed model is a viable approach for future human motion tracking applications.

The Mandible Ameliorates Facial Allograft Rejection and Is Associated with the Development of Regulatory T Cells and Mixed Chimerism.

Vascularized composite allografts contain various tissue components and possess relative antigenicity, eliciting different degrees of alloimmune responses. To investigate the strategies for achieving facial allograft tolerance, we established a mouse hemiface transplant model, including the skin, muscle, mandible, mucosa, and vessels. However, the immunomodulatory effects of the mandible on facial allografts remain unclear. To understand the effects of the mandible on facial allograft survival, we compared the diversities of different facial allograft-elicited alloimmunity between a facial osteomyocutaneous allograft (OMC), including skin, muscle, oral mucosa, and vessels, and especially the mandible, and a myocutaneous allograft (MC) including the skin, muscle, oral mucosa, and vessels, but not the mandible. The different facial allografts of a BALB/c donor were transplanted into a heterotopic neck defect on fully major histocompatibility complex-mismatched C57BL/6 mice. The allogeneic OMC (Allo-OMC) group exhibited significant prolongation of facial allograft survival compared to the allogeneic MC group, both in the presence and absence of FK506 immunosuppressive drugs. With the use of FK506 monotherapy (2 mg/kg) for 21 days, the allo-OMC group, including the mandible, showed prolongation of facial allograft survival of up to 65 days, whereas the myocutaneous allograft, without the mandible, only survived for 34 days. The Allo-OMC group also displayed decreased lymphocyte infiltration into the facial allograft. Both groups showed similar percentages of B cells, T cells, natural killer cells, macrophages, and dendritic cells in the blood, spleen, and lymph nodes. However, a decrease in pro-inflammatory T helper 1 cells and an increase in anti-inflammatory regulatory T cells were observed in the blood and lymph nodes of the Allo-OMC group. Significantly increased percentages of donor immune cells were also observed in three lymphoid organs of the Allo-OMC group, suggesting mixed chimerism induction. These results indicated that the mandible has the potential to induce anti-inflammatory effects and mixed chimerism for prolonging facial allograft survival. The immunomodulatory understanding of the mandible could contribute to reducing the use of immunosuppressive regimens in clinical face allotransplantation including the mandible.

Attitudes of Hand Surgeons and Hand Reconstruction Patients Toward Hand Allotransplantation in Taiwan.

BACKGROUND: Recent advances in immunosuppressive protocols have increasingly made hand allotransplantation a realistic reconstructive option with more than 100 cases performed worldwide. While attitudes toward allotransplantation have been assessed for North American surgeons and patients alike, similar assessments have previously remained unconducted in Asia in general and Taiwan in specific. This study examines the perceptions of both Taiwanese hand surgeons and hand reconstruction patients. METHODS: An email-based survey was sent to all active members of the Taiwanese Society for Surgery of the Hand. Surgeon training backgrounds and practice profiles were gathered as well as current beliefs on indications, risks, ethicality, priority of psychosocial issues, and obstacles to implementation. Patients receiving rehabilitation at Chang Gung Memorial Hospital Linkou after severe upper extremity injuries were invited to complete a patient survey. Demographics, injury characteristics, understanding of allotransplantation and immunosuppression, willingness to donate, and willingness to receive transplantation were assessed. RESULTS: Forty-four hand surgeons responded (24.3% response rate). The majority (61.4%) considered hand allotransplantation to be a high-risk operation, although 40% supported the development of hand allotransplantation under current techniques and immunosuppression. Bilateral hands loss was the most commonly accepted indication for transplant (90.9%), whereas dominant hand loss was less frequently accepted (43.2%). Treatment compliance and functional outcomes were the most frequent psychosocial issues of concern regarding patient counseling. Patient respondents were mostly in the fifth decade of life (29.5%) with at least a high school education (75.0%). Most were aware of the feasibility of hand transplantation (68.2%). Patients were more likely than surgeons to consider nondominant hand, multiple-digit, and thumb-only amputations as indications for transplantation. Functional outcomes and financial considerations were the most frequent patient concerns. CONCLUSIONS: This study indicates there is support for hand allotransplantation as a solution for limb loss in both hand surgeons and hand patients in Taiwan. This study adds to the lack of knowledge regarding surgeon and patient attitudes toward allotransplantation in Asia, although further work is required to assess the willingness of broader Taiwanese medical to refer candidates and for the general population to donate.