Conformation-driven strategy for resilient and functional protein materials.

The exceptional elastic resilience of some protein materials underlies essential biomechanical functions with broad interest in biomedical fields. However, molecular design of elastic resilience is restricted to amino acid sequences of a handful of naturally occurring resilient proteins such as resilin and elastin. Here, we exploit non-resilin/elastin sequences that adopt kinetically stabilized, random coil-dominated conformations to achieve near-perfect resilience comparable with that of resilin and elastin. We also show a direct correlation between resilience and Raman-characterized protein conformations. Furthermore, we demonstrate that metastable conformation of proteins enables the construction of mechanically graded protein materials that exhibit spatially controlled conformations and resilience. These results offer insights into molecular mechanisms of protein elastomers and outline a general conformation-driven strategy for developing resilient and functional protein materials.

Degradome sequencing reveals an integrative miRNA-mediated gene interaction network regulating rice seed vigor.

BACKGROUND: It is well known that seed vigor is essential for agricultural production and rice (Oryza sativa L.) is one of the most important crops in the world. Though we previously reported that miR164c regulates rice seed vigor, but whether and how other miRNAs cooperate with miR164c to regulate seed vigor is still unknown. RESULTS: Based on degradome data of six RNA samples isolated from seeds of the wild-type (WT) indica rice cultivar 'Kasalath' as well as two modified lines in 'Kasalath' background (miR164c-silenced line [MIM164c] and miR164c overexpression line [OE164c]), which were subjected to either no aging treatment or an 8-day artificial aging treatment, 1247 different target transcripts potentially cleaved by 421 miRNAs were identified. The miRNA target genes were functionally annotated via GO and KEGG enrichment analyses. By STRING database assay, a miRNA-mediated gene interaction network regulating seed vigor in rice was revealed, which comprised at least four interconnected pathways: the miR5075-mediated oxidoreductase related pathway, the plant hormone related pathway, the miR164e related pathway, and the previously reported RPS27AA related pathway. Knockout and overexpression of the target gene Os02g0817500 of miR5075 decreased and enhanced seed vigor, respectively. By Y2H assay, the proteins encoded by five seed vigor-related genes, Os08g0295100, Os07g0633100, REFA1, OsPER1 and OsGAPC3, were identified to interact with Os02g0817500. CONCLUSIONS: miRNAs cooperate to regulate seed vigor in rice via an integrative gene interaction network comprising miRNA target genes and other functional genes. The result provided a basis for fully understanding the molecular mechanisms of seed vigor regulation.

Clinical observation of two bone cement distribution modes after percutaneous vertebroplasty for osteoporotic vertebral compression fractures.

BACKGROUND: Current findings suggest that percutaneous vertebroplasty(PVP) is a suitable therapeutic approach for osteoporotic vertebral compression fractures (OVCFs). The present retrospective study aimed to investigate the differences in clinical efficacy and related complications between the two bone cement distribution modes. METHODS: We retrospectively reviewed the medical records of the patients with single-segment OVCFs who underwent bilateral percutaneous vertebroplasty. Patients were divided into blocky and spongy group according to the type of postoperative bone cement distribution. Clinical efficacy and related complications was compared between the two bone cement distribution modes on 24 h after the operation and last follow-up. RESULTS: A total of 329 patients with an average follow up time of 17.54 months were included. The blocky group included 131 patients, 109 females(83.2 %) and 22 males(16.8 %) with a median age of 72.69 ± 7.76 years, while the Spongy group was made up of 198 patients, 38 females(19.2 %) and 160 males(80.8 %) with a median age of 71.11 ± 7.36 years. The VAS and ODI after operation improved significantly in both two groups. The VAS and ODI in the spongy group was significantly lower than that in the blocky group, 24 h postoperatively, and at the last follow-up. There were 42 cases (12.8 %) of adjacent vertebral fractures, 26 cases (19.8 %) in the blocky group and 16 cases (8.1 %) in the spongy group. There were 57 cases (17.3 %) of bone cement leakage, 18 cases (13.7 %) in blocky group and 39 cases (19.7 %) in the spongy group. At 24 h postoperatively and at the last follow-up, local kyphosis and anterior vertebral height were significantly corrected in both groups, but gradually decreased over time, and the degree of correction was significantly higher in the spongy group than in the block group. The change of local kyphosis and loss of vertebral body height were also less severe in the spongy group at the last follow-up. CONCLUSIONS: Compared with blocky group, spongy group can better maintain the height of the vertebral body, correct local kyphosis, reduce the risk of the vertebral body recompression, long-term pain and restore functions.

Biosynthetic Electronic Interfaces for Bridging Microbial and Inorganic Electron Transport.

Electron transport in biological and inorganic systems is mediated through distinct mechanisms and pathways. Their fundamental mismatch in structural and thermodynamic properties has imposed a significant challenge on the effective coupling at the biotic/abiotic interface, which is central to the design and development of bioelectronic devices and their translation toward various engineering applications. Using electrochemically active bacteria, such as G. sulfurreducens, as a model system, here we report a bottom-up, biosynthetic approach to synergize the electron transport and significantly enhance the coupling at the heterogeneous junction. In particular, graphene oxide was exploited as the respiratory electron acceptors, which can be directly reduced by G. sulfurreducens through extracellular electron transfer, closely coupled with outer membrane cytochromes in electroactive conformation, and actively "wire" the redox centers to external electrical contacts. Through this strategy, the contact resistance at the biofilm/electrode interface can be effectively reduced by 90%. Furthermore, the cyclic voltammetry reveals that the electron transfer of the DL-1 biofilm transformed from a low-current (∼0.36 µA), rate-limited profile to a high-current (∼5 µA), diffusion-limited profile. These results suggested that the integration of rGO can minimize the charge transfer barriers at the biofilm/electrode interface. The more transparent contact at the DL-1/electrode interface also enables unambiguous characterization of the inherent electron transport kinetics across the electroactive biofilm independent of cell/electrode interactions. The current work represents a strategically new approach toward the seamless integration of biological and artificial electronics, which is expected to provide critical insights into the fundamentals of biological electron transport and open up new opportunities for applications in biosensing, biocomputing, and bioenergy conversion.

Modularized Field-Effect Transistor Biosensors.

Field-effect transistors (FETs), when functionalized with proper biorecognition elements (such as antibodies or enzymes), represent a unique platform for real-time, specific, label-free transduction of biochemical signals. However, direct immobilization of biorecognition molecules on FETs imposes limitations on reprogrammability, sensor regeneration, and robust device handling. Here we demonstrate a modularized design of FET biosensors with separate biorecognition and transducer modules, which are capable of reversible assembly and disassembly. In particular, hydrogel "stamps" immobilizing bioreceptors have been chosen to build biorecognition modules to reliably interface with FET transducers structurally and functionally. Successful detection of penicillin down to 0.25 mM has been achieved with a penicillinase-encoded hydrogel module, demonstrating effective signal transduction across the hybrid interface. Moreover, sequential integration of urease- and penicillinase-encoded modules on the same FET device allows us to reprogram the sensing modality without cross-contamination. In addition to independent bioreceptor encoding, the modular design also fosters sophisticated control of sensing kinetics by modulating the physiochemical microenvironment in the biorecognition modules. Specifically, the distinction in hydrogel porosity between polyethylene glycol and gelatin enables controlled access and detection of larger molecules, such as poly-l-lysine (MW 150-300 kDa), only through the gelatin module. Biorecognition modules with standardized interface designs have also been exploited to comply with additive mass fabrication by 3D printing, demonstrating potential for low cost, ease of storage, multiplexing, and great customizability for personalized biosensor production. This generic concept presents a unique integration strategy for modularized bioelectronics and could broadly impact hybrid device development.

Hydrogel Gate Graphene Field-Effect Transistors as Multiplexed Biosensors.

Nanoscale field-effect transistors (FETs) represent a unique platform for real time, label-free transduction of biochemical signals with unprecedented sensitivity and spatiotemporal resolution, yet their translation toward practical biomedical applications remains challenging. Herein, we demonstrate the potential to overcome several key limitations of traditional FET sensors by exploiting bioactive hydrogels as the gate material. Spatially defined photopolymerization is utilized to achieve selective patterning of polyethylene glycol on top of individual graphene FET devices, through which multiple biospecific receptors can be independently encapsulated into the hydrogel gate. The hydrogel-mediated integration of penicillinase was demonstrated to effectively catalyze enzymatic reaction in the confined microenvironment, enabling real time, label-free detection of penicillin down to 0.2 mM. Multiplexed functionalization with penicillinase and acetylcholinesterase has been demonstrated to achieve highly specific sensing. In addition, the microenvironment created by the hydrogel gate has been shown to significantly reduce the nonspecific binding of nontarget molecules to graphene channels as well as preserve the encapsulated enzyme activity for at least one week, in comparison to free enzymes showing significant signal loss within one day. This general approach presents a new biointegration strategy and facilitates multiplex detection of bioanalytes on the same platform, which could underwrite new advances in healthcare research.

miR164c and miR168a regulate seed vigor in rice.

MicroRNAs (miRNAs) are key regulators of gene expression in many important biological processes of plants. However, few miRNAs have been shown to regulate seed vigor. Here, we conducted microarray assays to analyze miRNA expression levels in seeds of the rice (Oryza sativa L.) cultivar ZR02. Results showed significant differences in the expression of 11 miRNAs between artificially aged and untreated control seeds. Among these, osa-miR164c was transcriptionally upregulated, while osa-miR168a was downregulated in artificially aged seeds; this was verified by quantitative real-time PCR analysis. Under the same aging condition, osa-miR164c overexpression in OE164c transgenic seeds and osa-miR168a silencing in MIM168a transgenic seeds of the rice cultivar Kasalath led to lower germination rates, whereas osa-miR164c silencing in MIM164c and osa-miR168a overexpression in OE168a resulted in higher seed germination rates compared with wild-type seeds. Meanwhile, changes in cytomembrane permeability of seeds and in the expression level of osa-miR164c target genes (OsPM27 and OsPSK5) and osa-miR168a target genes (OsAGO1 and OsPTR2) under aging conditions coincided with changes in seed vigor induced by osa-miR164c and osa-miR168a. Thus, genetic manipulation of miRNAs has important implications in the development of crop cultivars with high vigor and extended life span of seeds.

Arthroscopic subscapularis augmentation combined with capsulolabral reconstruction is safe and reliable.

PURPOSE: The study aimed to compare modified arthroscopic subscapularis augmentation (MASA) with tenodesis of the upper third of the subscapularis tendon using a tendon combined with capsulolabral reconstruction (Group A) or Bankart repair (Group B) for recurrent anterior shoulder instability (RASI). METHODS: A retrospective series of 49 patients underwent primary surgery for RASI with glenoid bone loss (GBL) < 25%. Outcomes included the Oxford Shoulder Instability Score (OSIS), Visual Analogue Scale (VAS) score, Rowe score, and American Shoulder and Elbow Surgeons (ASES) functional outcome scale score. Recurrent instability, sports activity level, and range of motion (ROM) were also analysed. RESULTS: No significant differences were observed at baseline. Forty-six patients were available for more than 2 years of follow-up. At the last follow-up after surgery, the patients in both groups had experienced significant improvements in all outcome scores (P < 0.05 for all), and obvious decreases in forward flexion and external rotation were noted in both groups (P < 0.05 for all). Group A had superior ASES scores, VAS scores, and OSISs (P < 0.05) but did not experience significant differences in either the Rowe score or ROM compared to Group B. Group A had lower rates of recurrent instability and superior outcomes for the return to sports activities. One patient in Group A had subluxation, and 4 patients in Group B had dislocation or subluxation. No patients in either group experienced neurovascular injury, joint stiffness, or surgical wound infection. CONCLUSION: For RASI with GBL < 25%, MASA with tenodesis of the upper third of the subscapularis tendon using a tendon combined with capsulolabral reconstruction was a safe technique that produced better outcomes in terms of ASES scores, VAS scores, OSISs, the return to sports, and postoperative recurrent instability and did not decrease the ROM compared to that achieved by arthroscopic Bankart repair. LEVEL OF EVIDENCE: III.

Core/Shell Bacterial Cables: A One-Dimensional Platform for Probing Microbial Electron Transfer.

Extracellular electron transfer (EET) from electrochemically active bacteria (EAB) plays a critical role in renewable bioelectricity harvesting through microbial fuel cells (MFC). Comprehensive interpretation and interrogation of EET mechanisms can provide valuable information to enhance MFC performance, which however are still restricted by the intrinsic complexity of natural biofilm. Here, we design core/shell EAB-encapsulating cables as a one-dimensional model system to facilitate EET studies, where the local microenvironments can be rationally controlled to establish structure-function correlations with full biological relevance. In particular, our proof-of-concept studies with Shewanella loihica PV-4 ( S. loihica) encapsulating cables demonstrate the precise modulation of fiber diameters (from 6.9 ± 1.1 to 25.1 ± 2.4 µm) and bacteria interactions, which are found to play important roles in programming the formation of different intercellular structures as revealed by in situ optical and ex situ electron microscopic studies. As-formed bacterial cables exhibit conductivity in the range of 2.5-16.2 mS·cm-1, which is highly dependent on the bacteria density as well as the nature and number of intercellular interconnections. Under electron-acceptor limited conditions, the closely contacted bacteria promote the development of high density self-assembling nanomaterials at cellular interfaces which can be directly translated to the increase of EET efficiency (16.2 mS·cm-1) as compared with isolated, remotely connected bacteria samples (6.4 mS·cm-1). Introducing exceeding concentrations of soluble electron acceptors during cell culture, however, substantially suppresses the formation of cellular interconnections and leads to significantly reduced conductivity (2.5 mS·cm-1). Frequency-dependent measurements further reveal that EET of EAB networks share similar characteristics to electron hopping in conductive polymer matrix, including dominant direct current-conduction in the low frequency region, and alternating current-induced additional electron hopping when the applied frequency is above the critical frequency (105 Hz). The current work represents a strategically new approach for noninvasively probing EET with rationally defined microenvironment and cellular interactions across a wide range of length scales, which is expected to open up new opportunities for tackling the fundamentals and implications of EET.

Arthroscopic revision release of gluteal muscle contracture after failed primary open surgery.

PURPOSE: The treatment of gluteal muscle contracture (GMC) after failed primary open release surgery has rarely been reported in the literature. GMC is a troublesome health problem in some developing countries, and it can result in the limitation of patients' hip function, leading to the development of inferiority complexes. The aim of this study is to evaluate the effect of arthroscopic revision surgery after failed primary open release on patients with GMC. METHODS: A total of 278 hips of 140 patients who underwent arthroscopic revision procedures after failed primary open surgeries were gathered from the department files. All patients were treated using a "three-step" arthroscopic release procedure by the same surgeon group. RESULTS: The mean follow-up for the 136 patients was 38.9 months. There was significant difference (P < 0.05) between the patients' mean post-revision and pre-operative results on the Harris scoring system. Unreleased contracture tissues that needed revision operations included the gluteus maximus, tensor fasciae latae muscle, and gluteus medius in all patients, and the gluteus minimus and hip capsule in 11.0% and 8.1% of patients, respectively. Short-term complications included subcutaneous bruising of the abdomen in 11 patients, extensive ecchymosis in the lateral thigh in 12 patients, and a transient reduction of muscle strength in all patients. No complications involving postoperative incision infection, nerve and blood vessel damage, or positive Trendelenburg sign occurred. Symptoms of hip snapping and limitation of range of motion (ROM), combined with a positive Trendelenburg sign in two patients after the primary open surgery, were all resolved except for the Trendelenburg sign through arthroscopic revision release. The overall satisfaction rate of the revision operations was 90.4%. CONCLUSION: The three-step arthroscopic release procedure is effective for failed primary open GMC surgeries as shown by improved post-operative function and patient satisfaction regardless of which primary procedure was performed.

General strategy for biodetection in high ionic strength solutions using transistor-based nanoelectronic sensors.

Transistor-based nanoelectronic sensors are capable of label-free real-time chemical and biological detection with high sensitivity and spatial resolution, although the short Debye screening length in high ionic strength solutions has made difficult applications relevant to physiological conditions. Here, we describe a new and general strategy to overcome this challenge for field-effect transistor (FET) sensors that involves incorporating a porous and biomolecule permeable polymer layer on the FET sensor. This polymer layer increases the effective screening length in the region immediately adjacent to the device surface and thereby enables detection of biomolecules in high ionic strength solutions in real-time. Studies of silicon nanowire field-effect transistors with additional polyethylene glycol (PEG) modification show that prostate specific antigen (PSA) can be readily detected in solutions with phosphate buffer (PB) concentrations as high as 150 mM, while similar devices without PEG modification only exhibit detectable signals for concentrations ≤10 mM. Concentration-dependent measurements exhibited real-time detection of PSA with a sensitivity of at least 10 nM in 100 mM PB with linear response up to the highest (1000 nM) PSA concentrations tested. The current work represents an important step toward general application of transistor-based nanoelectronic detectors for biochemical sensing in physiological environments and is expected to open up exciting opportunities for in vitro and in vivo biological sensing relevant to basic biology research through medicine.

Characteristic arthroscopic signs of cartilage injuries indicating concomitant occult medial meniscal peripheral tears of posterior horn.

BACKGROUND: Medial posterior horn meniscal tear is difficult to visualise during arthroscopy and is occasionally undetected by preoperative magnetic resonance imaging (MRI). Consequently, attention should be paid to performing a thorough examination and to some characteristic signs that indicate occult meniscal tear. The purpose of this study was to assess an indicative correlation between arthroscopic features of cartilage injury and a concomitant occult meniscal tear. METHODS: We performed a retrospective clinical and radiographic study of a consecutive series of patients between January 2013 and December 2014. Of 1,596 patients, all 78 with wave-like chondral injury of the medial femoral condyle diagnosed at arthroscopy were included in the study. The occurrence, pattern, location and concomitant pathology of medial meniscal injury were analysed. RESULTS: The characteristic wave sign associated with chondral injury in the medial femoral condyle was detected by MRI preoperatively in two cases only; all others were discovered intraoperatively at arthroscopy. Cartilage injury was rated as Outerbridge type II in 53 patients, type III in 24, and type IV in one. Wave sign defects were all characterised by their transverse orientation in the load-bearing femoral condyle. The occult longitudinal peripheral meniscus tear of the posterior horn was seen in all patients with a positive wave sign visualised under arthroscopy. The wave sign was positively correlated with medial peripheral meniscal injury of the posterior horn (P < 0.01). CONCLUSION: Wave sign chondral injury in the medial femoral condyle seen at arthroscopy is a characteristic indicator for concomitant occult medial longitudinal peripheral meniscus tears of the posterior horn. LEVEL OF EVIDENCE: Case series, Level IV.

Nanoparticle facilitated extracellular electron transfer in microbial fuel cells.

Microbial fuel cells (MFCs) have been the focus of substantial research interest due to their potential for long-term, renewable electrical power generation via the metabolism of a broad spectrum of organic substrates, although the low power densities have limited their applications to date. Here, we demonstrate the potential to improve the power extraction by exploiting biogenic inorganic nanoparticles to facilitate extracellular electron transfer in MFCs. Simultaneous short-circuit current recording and optical imaging on a nanotechnology-enabled platform showed substantial current increase from Shewanella PV-4 after the formation of cell/iron sulfide nanoparticle aggregates. Detailed characterization of the structure and composition of the cell/nanoparticle interface revealed crystalline iron sulfide nanoparticles in intimate contact with and uniformly coating the cell membrane. In addition, studies designed to address the fundamental mechanisms of charge transport in this hybrid system showed that charge transport only occurred in the presence of live Shewanella, and moreover demonstrated that the enhanced current output can be attributed to improved electron transfer at cell/electrode interface and through the cellular-networks. Our approach of interconnecting and electrically contacting bacterial cells through biogenic nanoparticles represents a unique and promising direction in MFC research and has the potential to not only advance our fundamental knowledge about electron transfer processes in these biological systems but also overcome a key limitation in MFCs by constructing an electrically connected, three-dimensional cell network from the bottom-up.

Rational growth of branched nanowire heterostructures with synthetically encoded properties and function.

Branched nanostructures represent unique, 3D building blocks for the "bottom-up" paradigm of nanoscale science and technology. Here, we report a rational, multistep approach toward the general synthesis of 3D branched nanowire (NW) heterostructures. Single-crystalline semiconductor, including groups IV, III-V, and II-VI, and metal branches have been selectively grown on core or core/shell NW backbones, with the composition, morphology, and doping of core (core/shell) NWs and branch NWs well controlled during synthesis. Measurements made on the different composition branched NW structures demonstrate encoding of functional p-type/n-type diodes and light-emitting diodes (LEDs) as well as field effect transistors with device function localized at the branch/backbone NW junctions. In addition, multibranch/backbone NW structures were synthesized and used to demonstrate capability to create addressable nanoscale LED arrays, logic circuits, and biological sensors. Our work demonstrates a previously undescribed level of structural and functional complexity in NW materials, and more generally, highlights the potential of bottom-up synthesis to yield increasingly complex functional systems in the future.

Over-the-Top Double-Bundle Revision Anterior Cruciate Ligament Reconstruction Technique With Hybrid Hamstring Tendon Autograft-Allograft and Associated Lateral Extra-articular Tenodesis.

Revision anterior cruciate ligament (ACL) presents many technical challenges that are not commonly seen in primary ACL reconstruction. The purpose of this article is to describe an alternative technique consisting of over-the-top double-bundle ACL revision combined with lateral extra-articular tenodesis using hybrid hamstring tendon autograft-allograft. This technique provides a valid treatment option in ACL revision surgery.

Fangji Huangqi decoction ameliorates membranous nephropathy through the upregulation of BNIP3-mediated mitophagy.

ETHNOPHARMACOLOGICAL RELEVANCE: Fangji Huangqi Decoction (FJHQ), a traditional Chinese medicinal formula outlined in Zhang Zhongjing's "Jin Gui Yao Lue" during the Han Dynasty, is often used to treat conditions characterized by symptoms like edema and dysuria, including membranous nephropathy (MN). Despite its proven clinical effectiveness, the exact mechanisms through which FJHQ acts on MN remain elusive. AIM OF THE STUDY: This study aimed to investigate whether FJHQ enhances BNIP3-mediated mitophagy in podocytes by promoting BNIP3 expression and whether this improvement leads to the amelioration of MN. MATERIALS AND METHODS: In this study, by establishing passive Heymann nephritis (PHN) rats, an experimental rat model of MN induced by sheep anti-rat Fx1A serum, we evaluated the effects of FJHQ in vivo. In vitro experiments were carried out by treating primary podocytes with experimental rat serum. Furthermore, the potential mechanism by which FJHQ acts through BNIP3 was further examined by transfecting primary podocytes with the siRNA of BNIP3 or the corresponding control vector. RESULTS: After 4 weeks, significant kidney damage was observed in the rats in the model group, comparatively, FJHQ markedly decreased urine volume, 24-h urinary protein, blood urea nitrogen (BUN), creatinine (Scr), and increased serum total albumin (ALB). Histology showed that FJHQ caused significant improvements in glomerular hyperplasia, and IgG immune complex deposition in MN rats. JC-1 fluorescence labelling and flow cytometry analysis showed that FJHQ could significantly increase mitochondrial membrane potential in vivo. In the mitochondria of MN model rats, FJHQ was able to down-regulate the expression of P62 and up-regulate the expression of BNIP3, LC3B, and LC3 II/LC3 I, according to Western blot and immunofluorescence studies. Furthermore, FJHQ has been shown to significantly up-regulate mitochondrial membrane potential, down-regulate P62 expression in mitochondria, and up-regulate the expression of BNIP3, LC3B, and LC3 II/LC3 I in mitochondria at the cellular level. After the administration of the autophagy inhibitor chloroquine, the serum of rats treated with FJHQ further increased the expression of LC3 II/LC3 I in primary podocytes, showing higher autophagy flow. After the interference of BNIP3 in podocytes, the effect of FJHQ on mitochondrial membrane potential and autophagy-related proteins almost disappeared. CONCLUSION: FJHQ enhanced mitophagy in podocytes by promoting the expression of BNIP3, thereby contributing to the amelioration of MN. This work reveals the possible underlying mechanism by which FJHQ improves MN and provides a new avenue for MN treatment.

Probing electron transfer mechanisms in Shewanella oneidensis MR-1 using a nanoelectrode platform and single-cell imaging.

Microbial fuel cells (MFCs) represent a promising approach for sustainable energy production as they generate electricity directly from metabolism of organic substrates without the need for catalysts. However, the mechanisms of electron transfer between microbes and electrodes, which could ultimately limit power extraction, remain controversial. Here we demonstrate optically transparent nanoelectrodes as a platform to investigate extracellular electron transfer in Shewanella oneidensis MR-1, where an array of nanoholes precludes or single window allows for direct microbe-electrode contacts. Following addition of cells, short-circuit current measurements showed similar amplitude and temporal response for both electrode configurations, while in situ optical imaging demonstrates that the measured currents were uncorrelated with the cell number on the electrodes. High-resolution imaging showed the presence of thin, 4- to 5-nm diameter filaments emanating from cell bodies, although these filaments do not appear correlated with current generation. Both types of electrodes yielded similar currents at longer times in dense cell layers and exhibited a rapid drop in current upon removal of diffusible mediators. Reintroduction of the original cell-free media yielded a rapid increase in current to ∼80% of original level, whereas imaging showed that the positions of > 70% of cells remained unchanged during solution exchange. Together, these measurements show that electron transfer occurs predominantly by mediated mechanism in this model system. Last, simultaneous measurements of current and cell positions showed that cell motility and electron transfer were inversely correlated. The ability to control and image cell/electrode interactions down to the single-cell level provide a powerful approach for advancing our fundamental understanding of MFCs.

The pattern of collagen production may contribute to the gluteal muscle contracture pathogenic process.

INTRODUCTION: Arthroscopic release is now the gold standard globally for gluteal muscle contracture (GMC) treatment. However, some patients fail to improve after the first operation and are forced to undergo a second operation. This study explores the essential role collagen fibers may play in muscle contracture in GMC. METHODS: From February 2010 to May 2018, 1041 hips of 543 GMC patients underwent arthroscopic release. Among them, 498 (91.7%) patients had bilateral GMC and were admitted to the retrospective cohort study. Pathological testing and type III collagen testing were used in contracture tissue studies. Single-cell RNA-sequencing analysis was applied to explore the role of fibroblasts in muscle repair. RESULTS: Compared with GMC II patients, GMC III patients displayed higher clinical symptoms (P < 0.05). Six weeks after the surgery, the patients in GMC II had a lower prominent hip snap rate, higher JOA score, and better hip range of motion (P < 0.05). Compared with normal muscle tissue, contracture-affected tissue tended to have more type III collagen and form shorter fibers. Recurrent GMC patients seemed to have a higher type III collagen ratio (P < 0.05). In contrast to normally repairable muscle defects, fibroblasts in non-repairable defects were shown to downregulate collagen-related pathways at the early and late stages of tissue repair. DISCUSSION: This study describes the arthroscopic release of GMC. Study findings include the suggestion that the collagen secretion function of fibroblasts and collagen pattern might influence the muscle repair ability and be further involved in the GMC pathogenic process.

RETRACTED: Chen et al. Clinical Effect of Arthroscopic Resection of Extra-Articular Knee Osteochondroma. J. Clin. Med. 2023, 12, 52.

Following publication, the authors of "Clinical Effect of Arthroscopic Resection of Extra-Articular Knee Osteochondroma" by Chen et al. [...].