Multicomponent Raman spectral regression using complete and incomplete models and convolutional neural networks.

With the advent of hyperspectral Raman imaging technology, especially the rapid and high-resolution imaging schemes, datasets with thousands to millions of spectra are now commonplace. Standard preprocessing and regression methods such as least squares approaches are time consuming and require input from highly trained operators. Here we propose a solution to this analytic bottleneck through a convolutional neural network trained fully on synthetic data and then applied to experimental measurements, including cases where complete spectral information is missing (i.e. an underdetermined model). An advantage of the model is that it combines background correction and regression into a single step, and does not require user-selected parameters. We compare our results with traditional least squares methods, including the popular asymmetric least squares (AsLS) approach. Our results demonstrate that the proposed CNN model boasts less sensitivity to parameter selection, and with a rapid processing speed, with performance equal to or better than comparison methods. The performance is validated on synthetic spectral mixtures, as well as experimentally measured single-vesicle liposome data.

Thrombospondin-1 induced programmed death-ligand 1-mediated immunosuppression by activating the STAT3 pathway in osteosarcoma.

Thrombospondin-1 (TSP1) is generally assumed to suppress the growth of osteosarcoma through inhibiting angiogenesis; however, it is unclear whether TSP1 could affect the antitumor immunity against osteosarcoma. We aimed to explore the immune-related tumor-promoting effects of TSP1 and decipher its underlying mechanism. First, we identified that TSP1 regulated programmed death-ligand 1 (PD-L1) expression, which was related to the CD8+ T cells anergy in osteosarcoma cells. The exact role of PD-L1 in the immunosuppressive effect of TSP1 was then further confirmed by the addition of the PD-L1 neutralizing Ab. With the addition of PD-L1 neutralizing Abs during cocultivation, the inhibition of CD8+ T cells was abolished to a certain extent. Further mechanistic investigations showed that TSP1-induced PD-L1 upregulation was achieved by activation of the signal transducer and activator of transcription 3 (STAT3) pathway. In vivo experiments also indicated that TSP1 overexpression could promote the growth of primary lesions, whereas TSP1 knockdown effectively inhibits the growth of the primary lesion as well as lung metastasis by restoring the antitumor immunity. Thrombospondin-1 knockdown combined with PD-L1 neutralizing Ab achieved a more pronounced antitumor effect. Taken together, our study showed that TSP1 upregulates PD-L1 by activating the STAT3 pathway and, therefore, impairs the antitumor immunity against osteosarcoma.

Super-resolved Raman imaging via galvo-painted structured line illumination.

Traditional line-scan Raman imaging features a rapid imaging speed while preserving complete spectral information, yet has diffraction-limited resolution. Sinusoidally structured line excitation can yield an improvement in the lateral resolution of the Raman image along the line's direction. However, given the need for the line and spectrometer slit to be aligned, the resolution in the perpendicular direction remains diffraction limited. To overcome this, we present here a galvo-modulated structured line imaging system, where a system of three galvos can arbitrarily orient the structured line on the sample plane, while keeping the beam aligned to the spectrometer slit in the detection plane. Thus, a two-fold isotropic improvement in the lateral resolution fold is possible. We demonstrate the feasibility using mixtures of microspheres as chemical and size standards. The results prove an improvement in the lateral resolution of 1.8-fold (limited by line contrast at higher frequencies), while preserving complete spectral information of the sample.

Fast confocal Raman imaging via context-aware compressive sensing.

Raman hyperspectral imaging is a powerful method to obtain detailed chemical information about a wide variety of organic and inorganic samples noninvasively and without labels. However, due to the weak, nonresonant nature of spontaneous Raman scattering, acquiring a Raman imaging dataset is time-consuming and inefficient. In this paper we utilize a compressive imaging strategy coupled with a context-aware image prior to improve Raman imaging speed by 5- to 10-fold compared to classic point-scanning Raman imaging, while maintaining the traditional benefits of point scanning imaging, such as isotropic resolution and confocality. With faster data acquisition, large datasets can be acquired in reasonable timescales, leading to more reliable downstream analysis. On standard samples, context-aware Raman compressive imaging (CARCI) was able to reduce the number of measurements by ∼85% while maintaining high image quality (SSIM >0.85). Using CARCI, we obtained a large dataset of chemical images of fission yeast cells, showing that by collecting 5-fold more cells in a given experiment time, we were able to get more accurate chemical images, identification of rare cells, and improved biochemical modeling. For example, applying VCA to nearly 100 cells' data together, cellular organelles were resolved that were not faithfully reconstructed by a single cell's dataset.

Targeting autophagy enhances atezolizumab-induced mitochondria-related apoptosis in osteosarcoma.

In this study, we identified the multifaceted effects of atezolizumab, a specific monoclonal antibody against PD-L1, in tumor suppression except for restoring antitumor immunity, and investigated the promising ways to improve its efficacy. Atezolizumab could inhibit the proliferation and induce immune-independent apoptosis of osteosarcoma cells. With further exploration, we found that atezolizumab could impair mitochondria of osteosarcoma cells, resulting in increased release of reactive oxygen species and cytochrome-c, eventually leading to mitochondrial-related apoptosis via activating JNK pathway. Nevertheless, the excessive release of reactive oxygen species also activated the protective autophagy of osteosarcoma cells. Therefore, when we combined atezolizumab with autophagy inhibitors, the cytotoxic effect of atezolizumab on osteosarcoma cells was significantly enhanced in vitro. Further in vivo experiments also confirmed that atezolizumab combined with chloroquine achieved the most significant antitumor effect. Taken together, our study indicates that atezolizumab can induce mitochondrial-related apoptosis and protective autophagy independently of the immune system, and targeting autophagy is a promising combinatorial approach to amplify its cytotoxicity.

Nanometer precise red blood cell sizing using a cost-effective quantitative dark field imaging system.

Because of the bulk, complexity, calibration requirements, and need for operator training, most current flow-based blood counting devices are not appropriate for field use. Standard imaging methods could be much more compact, inexpensive, and with minimal calibration requirements. However, due to the diffraction limit, imaging lacks the nanometer precision required to measure red blood cell volumes. To address this challenge, we utilize Mie scattering, which can measure nanometer-scale morphological information from cells, in a dark-field imaging geometry. The approach consists of a custom-built dark-field scattering microscope with symmetrically oblique illumination at a precisely defined angle to record wide-field images of diluted and sphered blood samples. Scattering intensities of each cell under three wavelengths are obtained by segmenting images via digital image processing. These scattering intensities are then used to determine size and hemoglobin information via Mie theory and machine learning. Validation on 90 clinical blood samples confirmed the ability to obtain mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration (MCHC), and red cell distribution width (RDW) with high accuracy. Simulations based on historical data suggest that an instrument with the accuracy achieved in this study could be used for widespread anemia screening.

Low resolution Raman: the impact of spectral resolution on limit of detection and imaging speed in hyperspectral imaging.

The majority of problems in analytical Raman spectroscopy are mathematically over-determined, where many more spectral variables are measured than analytic outputs (such as chemical concentrations) are calculated. Thus, to improve spectral throughput and simplify system design, some researchers have explored the use of low resolution Raman systems for cell or tissue classification, achieving accuracy independent of spectral resolution. However, the tradeoffs inherent in this approach have not been systematically studied. Here, we theoretically and experimentally explore the relationship between spectral resolution and analytical error. We show that decreased spectral resolution leads to spectral signal-to-noise ratio and therefore more reliable results and lower limits of detection for equivalent integration times in blind unmixing of hyperspectral images. Our theoretical analysis demonstrates that the primary benefit of low resolution Raman spectroscopy is in overcoming detector noise (such as thermal or electronic noise). Therefore, the benefits are most pronounced when utilizing lower-grade, uncooled detectors. Therefore, using a low-cost CMOS camera we experimentally demonstrate the ability of low resolution Raman spectroscopy to achieve substantially improved imaging performance compared to fully-resolved Raman spectral imaging, paving the way for cost-effective, pervasive Raman spectroscopy.

Combined Morpho-Chemical Profiling of Individual Extracellular Vesicles and Functional Nanoparticles without Labels.

Biological nanoparticles are important targets of study, yet their small size and tendency to aggregate makes their heterogeneity difficult to profile on a truly single-particle basis. Here we present a label-free system called 'Raman-enabled nanoparticle trapping analysis' (R-NTA) that optically traps individual nanoparticles, records Raman spectra and tracks particle motion to identify chemical composition, size, and refractive index. R-NTA has the unique capacity to characterize aggregation status and absolute chemical concentration at the single-particle level. We validate the method on NIST standards and liposomes, demonstrating that R-NTA can accurately characterize size and chemical heterogeneity, including determining combined morpho-chemical properties such as the number of lamellae in individual liposomes. Applied to extracellular vesicles (EVs), we find distinct differences between EVs from cancerous and noncancerous cells, and that knockdown of the TRPP2 ion channel, which is pathologically highly expressed in laryngeal cancer cells, leads the EVs to more closely resemble EVs from normal epithelial cells. Intriguingly, the differences in EV content are found in small subpopulations of EVs, highlighting the importance of single-particle measurements. These experiments demonstrate the power of the R-NTA system to measure and characterize the morpho-chemical heterogeneity of bionanoparticles.

MicroRNA-200a induces immunosuppression by promoting PTEN-mediated PD-L1 upregulation in osteosarcoma.

In this study, we identified microRNAs that regulate the expression of programmed death-ligand 1(PD-L1) in osteosarcoma and investigated their role in PD-L1-targeted immunotherapy. MicroRNA sequencing analysis showed that the expression of PD-L1 is regulated by microRNA-200a in U2OS, 143B, and K7 osteosarcoma cells. MicroRNA-200a overexpression induced the upregulation of PD-L1 in the osteosarcoma cells. CD8+ T cells co-cultured with microRNA-200a-overexpressing osteosarcoma cells showed reduced survival, proliferation, and secretion of granzyme B and perforin. The same phenomenon was also observed in the K7-derived syngeneic mouse model, as microRNA-200a promoted tumor growth by increasing the percentage of Foxp3+ regulatory T lymphocytes while reducing the proportions of CD4+, CD8+, and IFN-γ+ cytotoxic T lymphocytes. But microRNA-200a overexpression group was also more responsive to PD-L1-targeted immunotherapy than the controls. In addition, the tumor tissues from 32 osteosarcoma patients showed that high expression of microRNA-200a and PD-L1 was associated with poor tumor necrosis rate after chemotherapy. Moreover, we confirmed that tensin homolog deleted on chromosome ten (PTEN) could act as the target gene for microRNA-200a during the upregulation of PD-L1. Thus, our findings provide important and novel insight into a regulatory axis involving microRNA-200a/PTEN/ PD-L1 axis, which determines osteosarcoma growth and the efficacy of PD-L1-targeted immunotherapy.

[Treatment of AO/OTA type 31-A3 intertrochanteric fracture with proximal femoral nail antirotation combined with mini plate reconstruction of lateral femoral wall].

OBJECTIVE: To explore the effectiveness of proximal femoral nail antirotation (PFNA) combined with mini plate for reconstruction of lateral femoral wall in the treatment of type AO/Orthopaedic Trauma Association (AO/OTA) type 31-A3 intertrochanteric fracture. METHODS: The clinical data of 70 elderly patients with AO/OTA type 31-A3 intertrochanteric fracture treated between January 2013 and January 2018 were retrospectively analyzed. They were divided into group A (PFNA alone, 35 cases) and group B (PFNA combined with mini plate reconstruction of lateral femoral wall, 35 cases). There was no significant difference in the general data of gender, age, side, cause of injury, time from injury to operation between the two groups ( P>0.05). The operation time, intraoperative blood loss, fracture healing time, postoperative complications, and the tip apex distance (TAD) at 2 months after operation were recorded and compared between the two groups. Harris hip score was used to evaluate the function at 12 months after operation. RESULTS: Both groups were followed up 9-21 months, with an average of 16.6 months. The operation time and intraoperative blood loss in group A were significantly less than those in group B ( P<0.05); there was no significant difference in TAD between the two groups at 2 months after operation ( t=0.096, P=0.462). There were 5 complications (14.3%) occurred in group A, including 2 cases of blade perforating from the hip joint, 2 cases of screw back out, and 1 case of bone nonunion; only 1 case (2.9%) in group B had screw back out after operation; there was no significant difference in the incidence of complications between the two groups ( χ 2=2.917, P=0.088). All the fracture healed in group B, and 1 patient in group A suffered bone nonunion and eventually main nail fracture. The healing time of fracture in group A [(15.6±2.7) weeks] was significantly longer than that in group B [(12.5±2.5) weeks], showing significant difference ( t=2.064, P=0.023). At 12 months after operation, according to Harris score, the results were excellent in 5 cases, good in 9 cases, fair in 13 cases, and poor in 8 cases in group A, the qualified rate (Harris score>70) was 77.14%; and the results were excellent in 7 cases, good in 11 cases, fair in 16 cases, and poor in 1 case in group B, the qualified rate was 97.14%; there was significant difference in the qualified rate between the two groups ( χ 2=6.248, P=0.012). CONCLUSION: Compared with PFNA alone, the treatment of AO/OTA type 31-A3 intertrochanteric fracture with PFNA combined with mini plate reconstruction of lateral femoral wall can significantly reduce postoperative complications, promote fracture healing, and improve functional recovery of patients after operation.

Natural spider silk as a photonics component for humidity sensing.

Biological microfibers are remarkable materials with diversity in their chemistry, structure and functions that provide a range of solutions for photonic structures. Here we proposed and demonstrated a humidity detection technique for spectral tuning of whispering gallery modes (WGMs) in a cylindrical microresonator formed by a piece of spider egg sac silk (SpEss) from Araneus Ventricosus. We launched a supercontinuum laser into the SpEss via a tapered single-mode fiber to excite WGMs. When the ambient humidity changed, the profile diameter and effective refractive index of the SpEss changed, which caused the WGM resonant dips to shift. The experimental results showed that when the relative humidity (RH) changed from 20% to 75% RH, the average testing sensitivity of the proposed sensor was 389.1 pm/%RH and the maximum testing sensitivity was 606.7 pm/%RH in the range of 60% to 75% RH. Also, the proposed SpEss-based humidity sensor showed a fast response time of 494 ms and good repeatability with fluctuations less than 8% compared with the initial test values. The SpEss-based sensor expanded the application of spider silk as a biodegradable and biocompatible material in biochemical sensing.

Lin28 enhances de novo fatty acid synthesis to promote cancer progression via SREBP-1.

Lin28 plays an important role in promoting tumor development, whereas its exact functions and underlying mechanisms are largely unknown. Here, we show that both human homologs of Lin28 accelerate de novo fatty acid synthesis and promote the conversion from saturated to unsaturated fatty acids via the regulation of SREBP-1. By directly binding to the mRNAs of both SREBP-1 and SCAP, Lin28A/B enhance the translation and maturation of SREBP-1, and protect cancer cells from lipotoxicity. Lin28A/B-stimulated tumor growth is abrogated by SREBP-1 inhibition and by the impairment of the RNA binding properties of Lin28A/B, respectively. Collectively, our findings uncover that post-transcriptional regulation by Lin28A/B enhances de novo fatty acid synthesis and metabolic conversion of saturated and unsaturated fatty acids via SREBP-1, which is critical for cancer progression.

Open reduction and internal fixation of Gustilo type-I and type-II open pilon fractures using a lateral approach.

BACKGROUND: Traditional anteromedial incision for pilon fractures would further increase the damage to the subcutaneous tissues anterior and medial to tibia. In this study, we retrospectively evaluated the method and the outcomes of lateral approach for surgical treatment of Gustilo type-I and type-II open pilon fractures with medial soft tissue injuries. METHODS: From May 2014 to September 2017, 35 patients with Gustilo type-I and type-II open pilon fractures were treated with standard protocol using a lateral approach. The initial wound debridement and application of a spanning external fixator or traction of calcaneal tubercle were performed within 24 h and a definitive fixation was performed when the wound was healed. The mean time from primary surgery to definite surgery was 11.8 (range: 8-16) days. Postoperative radiographs, complications, bone union, and American Orthopedic Foot and Ankle Society (AOFAS) ankle/hind foot score were recorded. RESULTS: The mean follow-up period was 17 months (range: 13-23). The average time to bone union was 22 weeks (range: 18-25). In 35 patients, 2 patients had a superficial wound infection and another 1 patient showed limitation of ankle joint motion. No cases of deep infection, skin necrosis, and symptomatic implant reported. The mean AOFAS score was 89.8 (range: 84-95). On final outcome, 25 patients come under excellent and 10 patients had good result. CONCLUSION: From the results of this study, we can conclude that the lateral approach to treat Gustilo type-I and type-II open pilon fractures was a safe option with a low complication rate. On the other hand, it provides sufficient exposure to restore anatomic articulation, which is worthy of clinical recommendation.

Checkpoint Blockade in Combination With Doxorubicin Augments Tumor Cell Apoptosis in Osteosarcoma.

The aim of this study was to provide a basis for the theory that the combination of conventional chemotherapy and immunotherapy would be an effective treatment for osteosarcoma. Here, the expression of programmed death ligand 1 (PD-L1) in 26 clinical osteosarcoma tissue samples collected before and after chemotherapy was analyzed. The effects of osteosarcoma cells treated with doxorubicin, a conventional chemotherapeutic agent, on the proliferation and apoptosis of CD8 T lymphocytes were investigated in vitro. Thereafter, the effectiveness of doxorubicin combined with an anti-PD-L1 antibody as an osteosarcoma therapy was tested in 24 subcutaneous tumor mouse models. The results showed that the expression of PD-L1 was upregulated by chemotherapy in both the clinical osteosarcoma tissue samples and the osteosarcoma cell lines. The proliferation of CD8 T lymphocytes was inhibited, and apoptosis in CD8 T lymphocytes was enhanced by the doxorubicin-pretreated osteosarcoma cells, whereas this effect was reversed by the anti-PD-L1 antibody. A more effective result was observed when doxorubicin was combined with the anti-PD-L1 antibody in vivo. In short, the combination of conventional chemotherapy and an anti-PD-L1 antibody might be an effective option for osteosarcoma treatment, as anti-PD-L1 antibody can reverse the immunosuppression induced by chemotherapy.

Impact of high-mobility-group A2 overexpression on epithelial-mesenchymal transition in pancreatic cancer.

Background: Tumor metastasis causes high mortality in patients with malignancies. In carcinomas, overexpression of high-mobility-group A2 (HMGA2) in cancer cells would lead to tumor development and epithelial to mesenchymal transition (EMT), promoting metastasis. This study evaluated HMGA2 overexpression for its effects on pancreatic cancer (PC). Methods: HMGA2 protein levels were immunohistochemically assessed in human PC tissue specimens and evaluated for associations with patients' clinicopathological findings. In human PC CAPAN 1 cells after HMGA2 expression was silenced or overexpressed, Transwell migration and invasion assays were performed, and EMT marker levels (E-cadherin, N-cadherin and Vimentin) were determined by immunoblot. Results: HMGA2 and Vimentin were found in 43% and 45% of PC tissue samples, respectively, while E-cadherin was absent in 60%. HMGA2 expression, loss of E-cadherin and Vimentin expression were significantly associated with clinical stage, tumor differentiation and lymph node metastasis. More importantly, univariate and multivariate analysis demonstrated that HMGA2 expression is an independent prognostic factor for patients with pancreatic cancer. Meanwhile, HMGA2-silenced CAPAN 1 cells showed reduced migration and invasion ability while HMGA2-overexpressed CAPAN 1 cells showed increased migration and invasion ability. Increased E-cadherin (epithelial marker) and reduced N-cadherin and Vimentin (mesenchymal markers) were found in HMGA2-silenced cells, while reduced E-cadherin and increased N-cadherin and Vimentin were found in HMGA2-overexpressed cells. Furthermore, Snail and Zeb1 (transcriptional factors) were reduced in HMGA2-silenced cells and increased in HMGA2-overexpressed cells. Conclusion: Our findings demonstrate that HMGA2 expression correlates with advanced tumor grades, lymph node metastasis and poor prognosis and may be a novel prognosis/therapeutic marker for PC.

A modified tarsal sinus approach for intra-articular calcaneal fractures.

BACKGROUND: Plate fixation using traditional lateral L-shape approach for intra-articular calcaneal fractures is complicated by 30% of wound complications, and the lateral small incision techniques with a tarsal sinus approach cannot sufficiently address all the fragments. A modified tarsal sinus approach with combined advantages of traditional lateral L-shape and tarsal sinus approaches for the treatment of intra-articular calcaneal fractures was developed. METHOD: This prospective study included 29 patients (13 Sanders type II and 16 type III) with calcaneal fractures were managed with this technique. Calcaneal height, width, length, Bohler's angle, and Gissane angle were measured preoperatively, postoperatively, and at 1-year follow-up. Functional outcomes were assessed based on American Orthopedic Foot and Ankle Society (AOFAS) ankle/hindfoot score. RESULTS: Twenty-nine patients with average follow-up time of 18 (range 13-29) months were included. The radiographs demonstrated significant corrections of the Bohler's angle and Gissane angle, calcaneal width, length, and height from preoperation to postoperation and 1-year follow-up. Among all follow-up patients, one case had skin necrosis but healed after dressing. Another case had symptoms of numbness in the sural innervation area, which disappeared after 5 months of physical therapy and drug therapy. One case showed degenerative changes of subtalar joint at 1-year follow-up. No other wound complications like incision infection (superficial or deep) and wound dehiscence occurred. At 1-year follow-up, the mean AOFAS score was 90.2 ± 17.7 (range 70-98) and the good and excellent rate was 89.7%. CONCLUSION: The modified tarsal sinus approach in the treatment of Sander's type II and III calcaneal fractures allowed adequate reduction and rigid fixation with low incidence of wound complications. Compared to sinus tarsi approach, this technique required shorter learning curve and was more easily mastered by young orthopedic surgeons. Thus, it was worthy of application clinically.

Patellar height influences knee function in patients with aggressive bone tumors of the proximal tibia after endoprosthetic reconstruction.

BACKGROUND: The proximal tibia is the second most common site of aggressive bone tumors. In proximal tibia resection, the patellar tendon is sectioned one to two centimeters from its insertion on the tibial tubercle, which makes it technically challenging to achieve an appropriate patellar height and firm fixation of the patellar tendon. The purpose of this study was to determine whether the patellar height influences knee function after proximal tibia endoprosthetic reconstruction (EPR). METHODS: Twenty-nine patients with pathologically confirmed aggressive bone tumors in the proximal tibia were retrospectively analyzed. We used the Insall-Salvati ratio (ISR) and the Blackburne-Peel index (BPI) to radiographically analyze the patellar height. Functional outcomes were retrospectively assessed using the Musculoskeletal Tumor Society (MSTS) score, the Oxford Knee Score (OKS) and the range of motion (ROM) which was evaluated through extensor lag and active flexion. Univariate analysis with Pearson's correlation and a multivariate linear regression of patient characteristics and surgery-related changes were performed. RESULTS: The postoperative ISRs were negatively correlated with the functionality domain of the MSTS score (function, gait, walking) and the OKS. Pearson's correlation analysis showed a significant correlation between the postoperative ISR and extensor lag. The change in patellar height had no impact on the active flexion of the knee. CONCLUSIONS: Patellar height is an independent factor contributing to knee function after proximal tibia EPR. The quality of patellar tendon reconstruction is a key point in proximal tibia EPR after tumor resection.

Adaptive Fibrogenic Reprogramming of Osteosarcoma Stem Cells Promotes Metastatic Growth.

It is well established that fibrotic remodeling of the tumor microenvironment favors tumorigenesis, but whether fibrosis underlies malignant progression in other ways is unclear. Here, we report that adaptive myofibroblastic reprogramming of osteosarcoma stem cells (OSCs) results in a critical advantage when establishing lung macro-metastases and spheroid growth but does not affect the growth of primary lesions or monolayer cultures. FGFR2 signaling in OSCs initiates fibrosis, whereas the resultant fibronectin (FN) auto-deposition sustains fibrogenic reprogramming and OSC growth, resembling the process employed by non-malignant myofibroblasts to cause tissue fibrosis. Furthermore, we provide evidence that nintedanib targets the pan FGFR-FN axis to disrupt lung metastasis without affecting the bone lesion growth of OSCs. Thus, myofibroblastic reprogramming of human OSCs in the lungs might represent a druggable trait for treating a deadly metastatic complication.

Clinical and radiological outcome of Gustilo type III open distal tibial and tibial shaft fractures after staged treatment with posterolateral minimally invasive plate osteosynthesis (MIPO) technique.

OBJECTIVES: To evaluate the methods and the outcomes of Gustilo type III open distal tibial and tibial shaft fractures with severe anterior and medial soft-tissue injuries, treated with posterolateral minimally invasive plate osteosynthesis (MIPO) technique. METHODS: From May 2015 to May 2016, 10 patients with Gustilo type III open distal tibial and tibial shaft fractures with severe anterior and medial soft-tissue injuries (Gustilo-Anderson classification IIIA, 6; IIIB, 4) were treated with staged protocol using posterolateral minimally invasive plate osteosynthesis (MIPO) technique. The initial wound lavage, debridement, and application of a spanning external fixator were performed within 24 h and the mean interval from injury to definitive surgical treatment was 12.8 (range 4-21) days. An additional bone graft was performed in two patients when definitive internal fixation was performed. All patients were followed to union. Postoperative radiographs, postoperative complications, bone union, ankle joint motion, and limb functional outcome information of AOFAS ankle-hindfoot score were recorded. RESULTS: The mean follow-up period was 17.8 (range 12-26) months. The mean interval to bony union was 25.8 (range 20-40) weeks. Bone union was achieved in all cases. There were no complications, such as incision breakdown, deep infection, or impingement of the flexor hallucis longus tendon. The average AOFAS score was 90 (range 83-96). In ten patients, two patients had a superficial wound infection and another one patient showed a 6° varus deformity. CONCLUSIONS: Staged treatment using MIPO technique through a posterolateral approach is a reasonable and safe treatment option for open distal tibial and tibial shaft fractures, especially Gustilo type III with severe anterior and medial soft-tissue injuries. However, it should have a higher level of research evidence in more patients to confirm the safety of the clinical application of this technique.

Design of a portable phantom device to simulate tissue oxygenation and blood perfusion.

We propose a portable phantom system for calibration and validation of medical optical devices in a clinical setting. The phantom system comprises a perfusion module and an exchangeable tissue-simulating phantom that simulates tissue oxygenation and blood perfusion. The perfusion module consists of a peristaltic pump, two liquid storage units, and two pressure suppressors. The tissue-simulating phantom is fabricated by a three-dimensional (3D) printing process with microchannels embedded to simulate blood vessels. Optical scattering and absorption properties of biologic tissue are simulated by mixing graphite powder and titanium dioxide powder with clear photoreactive resin at specific ratios. Tissue oxygen saturation (StO2) and blood perfusion are simulated by circulating the mixture of blood and intralipid at different oxygenation levels and flow rates. A house-made multimodal imaging system that combines multispectral imaging and laser speckle imaging are used for non-invasive detection of phantom oxygenation and perfusion, and the measurements are compared with those of a commercial Moor device as well as numerical simulation. By acquiring multimodal imaging data from one phantom and applying the calibration factors in different settings, we demonstrate the technical feasibility to calibrate optical devices for consistent measurements. By simulating retina tissue vasculature and acquiring functional images at different tissue oxygenation and blood perfusion levels, we demonstrate the clinical potential to simulate tissue anomalies. Our experiments imply the clinical potential of a portable, low-cost, and traceable phantom standard to calibrate and validate medical optical devices for improved performance.