Effect of Inorganic Fillers on Electrical and Mechanical Properties of Ceramizable Silicone Rubber.

Ceramizable silicone rubber (CSR) composed of silicone rubber matrix and inorganic fillers can be transformed into a dense flame-retardant ceramic upon encountering high temperatures or flames. Conventionally, CSR can be sintered into a dense ceramic at temperatures above 1000 °C, which is higher than the melting point of a copper conductor used in a power cable. In this study, the vulcanization process and mass ratio of inorganic fillers of CSR were studied to lower its ceramization temperature to 950 °C. The electrical and mechanical properties of CSRs and their ceramic bulks were studied with various ratios of wollastonite and muscovite. It was found that the CSR samples could be successfully fabricated using a two-step vulcanization technique (at 120 °C and 150 °C, respectively). As a high ratio of muscovite filler was introduced into the CSR, the sample presented a high dc electrical resistivity of 6.713 × 1014 Ω·cm, and a low dielectric constant of 4.3 and dielectric loss of 0.025 at 50 Hz. After the thermal sintering (at 950 °C for 1 h) of the CSR sample with a high ratio of muscovite, the ceramic sample exhibits a dense microstructure without any pores. The ceramic also demonstrates excellent insulating properties, with a volume resistivity of 8.69 × 1011 Ω·cm, and a low dielectric loss of 0.01 at 50 Hz. Meanwhile, the three-point bending strength of the ceramic sample reaches a value of 110.03 MPa. This study provides a potential route to fabricate CSR used for fire-resistant cables.

Airway collapse hinders recovery in bronchoscopy therapy for postintubation tracheal stenosis patients.

BACKGROUND: Expiratory central airway collapse (ECAC) following postintubation airway stenosis (PITS) is a rare phenomenon. The impact of airway malacia and collapse on the prognosis and the success rate of bronchoscopic interventional therapy in patients with PITS had been inadequately investigated. OBJECTIVE: The aim of this research was to assess the influence of airway malacia and collapse on the efficacy of bronchoscopic interventional therapy in patients with PITS. DESIGN: This retrospective analysis examined the medical documentation of individuals diagnosed with PITS who underwent bronchoscopic intervention at the tertiary interventional pulmonology center of Emergency General Hospital from 2014 to 2021. MAIN OUTCOME MEASURES: Data pertaining to preoperative, perioperative, and postoperative stages were documented and subjected to analysis. RESULTS: The patients in malacia and collapse group (MC group) exhibited a higher frequency of perioperative complications, including intraoperative hypoxemia, need for reoperation within 24 h, and postoperative intensive care unit admission rate (P < 0.05, respectively). Meanwhile, patients in group MC demonstrated significantly worse postoperative scores (higher mMRC score and lower KPS score) compared to those in pure stenosis group (P < 0.05, respectively), along with higher degrees of stenosis after treatment and a lower success rate of bronchoscopic intervention therapy cured (P < 0.05, respectively). Pearson analysis results showed that these terms were all significantly correlated with the occurrence of airway malacia and collapse in the airway (P < 0.05, respectively). CONCLUSION: The presence of malacia or collapse in patients with PITS was associated with increased perioperative complications following bronchoscopic interventional therapy, and significantly reduced the long-term cure rate compared to patients with pure tracheal stenosis. Trial registration Chinese Clinical Trial Registry on 06/12/2021. REGISTRATION NUMBER: ChiCTR2100053991.

The effect of phosphorylation on the conformational dynamics and allostery of the association of death-associated protein kinase with calmodulin.

Protein phosphorylation plays an important role in the signal transduction and is capable of regulation of cell activity. The death-associated protein kinase 1 (DAPK1), as a Ser/Thr kinase, interacts with calmodulin (CaM) to regulate apoptotic and autophagic signaling. Autophosphorylation of DAPK1 at Ser308 located at the autoregulatory domain (ARD) blocks CaM binding and inhibits kinase catalytic activity. However, the mechanism underlying the influence of Ser308 phosphorylation (pS308) on the DAPK1 activity remains unclear. Here, we performed multiple, microsecond length molecular dynamics (MD) simulations, the molecular mechanics generalized Born/surface area (MM-GBSA) binding free energy calculations, principal component analysis, and dynamic cross-correlation analysis to unravel the conformational dynamics and allostery of the DAPK1 - CaM interaction triggered by the pS308 at the ARD. MD simulations showed that pS308 affected the conformational stability of the DAPK1 - CaM complex. Further energetic and structural exploration revealed that pS308 weakened the association of the phosphorylated DAPK1 to CaM, which lowered the susceptibility of DAPK1 to be activated by CaM. This result can provide mechanistic insights into the molecular underpinning through which the DAPK1 kinase activity is modulated by the auto-phosphorylation.Communicated by Ramaswamy H. Sarma.

Nanoparticles targeting mutant p53 overcome chemoresistance and tumor recurrence in non-small cell lung cancer.

Non-small cell lung cancer (NSCLC) shows high drug resistance and leads to low survival due to the high level of mutated Tumor Protein p53 (TP53). Cisplatin is a first-line treatment option for NSCLC, and the p53 mutation is a major factor in chemoresistance. We demonstrate that cisplatin chemotherapy increases the risk of TP53 mutations, further contributing to cisplatin resistance. Encouragingly, we find that the combination of cisplatin and fluvastatin can alleviate this problem. Therefore, we synthesize Fluplatin, a prodrug consisting of cisplatin and fluvastatin. Then, Fluplatin self-assembles and is further encapsulated with poly-(ethylene glycol)-phosphoethanolamine (PEG-PE), we obtain Fluplatin@PEG-PE nanoparticles (FP NPs). FP NPs can degrade mutant p53 (mutp53) and efficiently trigger endoplasmic reticulum stress (ERS). In this study, we show that FP NPs relieve the inhibition of cisplatin chemotherapy caused by mutp53, exhibiting highly effective tumor suppression and improving the poor NSCLC prognosis.

Early and Mid-Term Outcomes of Using the Chimney Technique in Redo Mitral Valve Replacement in Patients with a Small Mitral Annulus.

The outcomes of redo mitral valve replacement (Re-MVR) in a small mitral annulus with the use of the chimney technique are not well documented. The purpose of this study is to present our early experience with this group of patients, illustrating the periop-erative complications and mortality outcomes. From 2019 to 2020, 77 consecutive patients underwent Re-MVR with the use of the chimney technique because of a small mitral annulus. To evaluate heart structural integrity and clinical outcomes, postoperative clinical data and echocardiograms were examined. The mean age was 56.7 ± 15.98 years. All patients underwent mitral valve surgery, of which 62 were mitral valve replacements, 7 mitral valve repairs, and 8 double valve replacements. The preoperative mitral valve mean gradient was 18.07 ± 9.40 mmHg, and the postoperative mitral prosthesis size was 28.51 ± 1.22 mm. The median increment of mitral size enlargement was 4 (0, 6) valve sizes. The mean mitral gradient coming out of the operating room was 10.34 ± 2.12 mmHg, and at the follow-up echocardiogram performed at 3 years after the procedure, it was 10.36 ± 1.70 mmHg. One-year survival was 93.3%, while the 4-year survival rate was 89.3%, with no reoperation. The use of the chimney technique in small mitral valve re-mitral valve replacement results in larger valve sizes. Moreover, the mean gradients over the mitral valve are acceptable both intraoperatively and over time.

Clinical outcomes of short rod technique in posterior lumbar interbody fusion surgery: a minimum of 2-year follow-up.

PURPOSE: We present for the first time a novel entry point of pedicle screws (Short Rod Technique, SRT), which can avoid superior facet violation and has been verified as a safe screw placement method. The purpose of this study is to determine the clinical outcomes of SRT in posterior lumbar interbody fusion (PLIF) surgery. METHODS: We retrospectively analyzed the clinical outcomes of 89 patients who received SRT and 109 patients who received PLIF surgery with regular entry points of pedicle screws with a minimum of 2 years of follow-ups. Patients were divided into three groups according to the number of fusion segments, and the clinical outcomes of the three groups were compared. RESULTS: The length of the wound and the length of rods were significantly shorter in the each SRT group. Less intraoperative blood loss was observed in the SRT group in patients with a single segment and two segments fusions, but not in three segments fusions. Fewer degenerations of the upper adjacent segment were observed in the SRT group in patients with a single segment and three segments fusions. In addition, less postoperative wound pain related to PLIF surgery was observed in the SRT group in patients with two and three segments fusions. CONCLUSION: SRT has been validated as an effective technique with good clinical outcomes, especially for reducing the occurrence of upper ASD in PLIF surgery with a single segment and three segments. The present study provides spinal surgeons with a novel method for performing PLIF surgery.

Lung isolation-a personalized and clinically adapted approach to control bronchoscopy-associated acute massive airway hemorrhage.

BACKGROUND: The current concept of bronchoscopy-associated massive airway hemorrhage is not accurate enough, and the amount of bleeding as the only evaluation criterion cannot comprehensively evaluate magnitude of the effects and the severity. OBJECTIVE: To propose the concept of bronchoscopy-associated acute massive airway hemorrhage, analyze its impact on patients and highlight the treatment approach of acute massive airway hemorrhage without ECMO support. DESIGNS: A retrospective cohort study. SETTING: Include all patients who received bronchoscopy intervention therapy at Interventional Pulmonology Center of Emergency General Hospital from 2004 to December 2021. PATIENTS: 223 patients met the inclusion criteria. INTERVENTION: Patients were divided into two groups: acute massive airway hemorrhage group (n = 29) and non-acute massive airway hemorrhage group (n = 194). MAIN OUTCOME MEASURES: Perioperative adverse events between two groups were the main outcome. Secondary outcome was the impact of lung isolation on patient in group Acute. RESULTS: The incidence of acute massive airway hemorrhage was 0.11%, and the incidence of non-acute massive airway hemorrhage was 0.76% in this study. There were significant differences in the incidence of intraoperative hypoxemia, lowest SpO2, hemorrhagic shock, cardiopulmonary resuscitation, intraoperative mortality, and transfer to ICU between acute group and non-acute group (P<0.05, respectively). Lung isolation was used in 12 patients with acute massive airway hemorrhage, and only 2 patients died during the operation. CONCLUSION: Bronchoscopy-associated acute massive airway hemorrhage had more serious impact on patients due to rapid bleeding, blurred vision of bronchoscopy, inability to stop bleeding quickly, blood filling alveoli, and serious impact on oxygenation of the lung lobes. Polyvinyl chloride single-lumen endotracheal intubation for lung isolation, with its characteristics of low difficulty, wide applicability and available in most hospitals, may reduce the intraoperative mortality of patients with bronchoscopy-associated acute massive airway hemorrhage. TRIAL REGISTRATION: Chinese Clinical Trial Registry on 13/03/2022. REGISTRATION NUMBER: ChiCTR2200057470.

Early outcomes of the "Chimney" commando procedure in the small aortic and mitral annuli.

Background: Commando procedure, the surgical replacement of the mitral and aortic valves combined with reconstruction of the fibrosa fibrous body, is a technical challenge in patients with small aortic and mitral annuli. In this study, we evaluated the safety and early outcomes of the "Chimney" modality of the Commando procedure, in patients with small aortic and mitral annuli, after prior valve surgery, using a self-assembled valved conduit. Methods: From April 2021 to April 2022, 30 consecutive cases of the "Chimney" Commando procedure, with a self-assembled valved conduit and other combined cardiac procedures, were fully performed for re-operative patients with small aortic roots. Data were obtained through a medical record review, at the Asian Heart Hospital in Wuhan, China. Results: The patient's mean age was 52.7 ± 13.53 years, with 93.3% females. All patients had a previous heart valve surgery, 90% of which had double valve replacement (DVR). Hospital death occurred in 3.3% (n = 1) of the patients, due to malignant arrhythmias and multiorgan failure. Postoperative echocardiogram exams showed that the sizes of the aortic and mitral valve prostheses were 24.23 ± 1.60 mm and 28.33 ± 1.21 mm, respectively. All patients had intact intervalvular fibrosa (IVF) repair and no patient had any aberration in the left heart chamber communication. With the exception of one postoperative sick sinus syndrome and one re-sternotomy for bleeding, there were no significant postoperative complications, such as mortality, renal failure requiring ongoing dialysis, or mediastinitis. Echocardiography exams in the sixth postoperative month showed that the mean gradients of the aortic and mitral valves were 16.26 ± 6.44 mmHg and 11.24 ± 4.90 mmHg, respectively. Conclusions: In comparison with the standard Commando operation, the early outcomes and safety of the "Chimney" Commando procedure proved to be a feasible therapeutic option for patients with small aortic and mitral annuli, after prior valve operations. This approach enables the enlargement of the aortic and mitral annuli and the implantation of the necessary valve prosthesis.

Nanoengineered mesenchymal stem cell therapy for pulmonary fibrosis in young and aged mice.

Pulmonary fibrosis (PF) is an age-related interstitial lung disease that results in notable morbidity and mortality. The Food and Drug Administration-approved drugs can decelerate the progression of PF; however, curing aged patients with severe fibrosis is ineffective because of insufficient accumulation of these drugs and wide necrocytosis of type II alveolar epithelial cells (AEC IIs). Here, we constructed a mesenchymal stem cell (MSC)-based nanoengineered platform via the bioconjugation of MSCs and type I collagenase-modified liposomes loaded with nintedanib (MSCs-Lip@NCAF) for treating severe fibrosis. Specifically, MSCs-Lip@NCAF migrated to fibrotic lungs because of the homing characteristic of MSCs and then Lip@NCAF was sensitively released. Subsequently, Lip@NCAF ablated collagen fibers, delivered nintedanib into fibroblasts, and inhibited fibroblast overactivation. MSCs differentiated into AEC IIs to repair alveolar structure and ultimately promote the regeneration of damaged lungs in aged mice. Our findings indicated that MSCs-Lip@NCAF could be used as a promising therapeutic candidate for PF therapy, especially in aged patients.

Thermal conductivity effect on thermophoresis of charged spheroidal colloids in aqueous media.

Thermophoresis of spheroidal colloids in aqueous media under the thermal conductivity effect is analyzed. The thermophoretic velocity and the thermodiffusion coefficient of spheroidal colloids have been formulated for extremely thin electric double layer (EDL) cases. Furthermore, a numerical thermophoretic model is built for arbitrary EDL thickness cases. The parametric studies show that the thermal conductivity mismatch of particle and liquid gives rise to a nonlinear temperature region around the spheroid, with the thickness close to the minor semiaxis. When the EDL region is thin relative to such nonlinear temperature region, the thermal conductivity effect on the thermophoresis of spheroidal colloids is significant, which strongly depends on the ratio of the minor semiaxis to the EDL thickness, the thermal conductivity ratio of particle to liquid, and the particle aspect ratio. Finally, to estimate the thermodiffusion coefficient of spheroidal colloids with arbitrary thermal conductivity, electrolyte concentration, and particle shape, the average dimensionless axial temperature gradient on the spheroidal equator plane in the EDL region is proposed.

Remediation of Acid Mine Drainage (AMD) Using Steel Slag: Mechanism of the Alkalinity Decayed Process.

Steel slag has been proven to be an effective environment remediation media for acid neutralization, and a potential aid to mitigate acid mine drainage (AMD). Yet its acid neutralization capacity (ANC) is frequently inhibited by precipitate after a period of time, while the characteristics of the precipitate formation process are unclear yet. In this study, ANC for basic oxygen steel slag was conducted by neutralization experiments with dilute sulfuric acid (0.1 M) and real AMD. Some partially neutralized steel slag samples were determined by X-ray diffraction (XRD), scanning electron microscopy combined with an energy dispersive spectrometer (SEM-EDS), and N2 adsorption tests to investigate the potential formation process of the precipitate. The results indicated that Ca-bearing constitutes leaching and sulfate formation were two main reactions throughout the neutralization process. A prominent transition turning point from leaching to precipitate was at about 40% of the neutralization process. Tricalcium silicate (Ca3SiO5) played a dominant role in the alkalinity-releasing stage among Ca-bearing components, while the new-formed well crystalline CaSO4 changed the microstructure of steel slag and further hindered alkaline components releasing. For steel slag of 200 mesh size, the ANC value for the steel slag sample was 8.23 mmol H+/g when dilute sulfate acid was used. Neutralization experiments conducted by real AMD confirmed that the steel slag ANC was also influenced by the high contaminants, such as Fe2+, due to the hydroxides precipitate reactions except for sulfate formation reactions.

Evaluation of Supraglottic Jet Oxygenation and Ventilation in 105 Patients During Bronchoscopy Using the Twinstream® Microprocessor-Controlled Jet Ventilator and the Wei Nasal Jet® Tube.

BACKGROUND The Twinstream® ventilator is a microprocessor-controlled electric jet ventilator that allows the simultaneous application of 2 different jet streams, one at low frequency and one at high frequency to result in pulsatile bi-level (p-BLV) mode of ventilation. This study aimed to evaluate supraglottic jet oxygenation and ventilation in 105 patients during bronchoscopy using the Twinstream® microprocessor-controlled jet ventilator and the Wei Nasal Jet® (WNJ) tube. MATERIAL AND METHODS Patients were randomly divided into 2 parallel groups (N=50 per group): group W using the WNJ tube and group M using an endoscopic face mask connected to Twinstream® microprocessor-controlled jet ventilator under monitored anesthesia care. Arterial blood gas was examined and recorded 15 minutes after the initiation of procedure. The demographic and clinical characteristics, procedure duration, doses of anesthetics, and adverse events in the 2 groups were also recorded. RESULTS The arterial partial pressure of carbon dioxide (PaCO2) (P=0.006) and lactic acid (P=0.001) were significantly lower, while pH (P=0.024) was significantly higher than in the group M. Pearson analysis showed that PaCO2 was significantly correlated with ventilation tools (P=0.006) and procedure duration (P=0.003). Multiple linear regression analysis showed that ventilation tools and procedure duration were both independent influencing factors (P=0.006, P=0.002). CONCLUSIONS Supraglottic jet oxygenation and ventilation using the WNJ tube can reduce PaCO2 and had advantages in enhancing oxygenation and ventilation function in patients during bronchoscopy intervention therapy under monitored anesthesia care.

Pathological collagen targeting and penetrating liposomes for idiopathic pulmonary fibrosis therapy.

Idiopathic pulmonary fibrosis (IPF) is a fibrotic interstitial lung disease in which collagen progressively deposits in the supporting framework of the lungs. The pathological collagen creates a recalcitrant barrier in mesenchyme for drug penetration, thus greatly restricting the therapeutical efficacy. On the other hand, this overloaded collagen is gradually exposed to the bloodstream at fibrotic sites because of the vascular hyperpermeability, thus serving as a potential target. Herein, pathological collagen targeting and penetrating liposomes (DP-CC) were constructed to deliver anti-fibrotic dual drugs including pirfenidone (PFD) and dexamethasone (DEX) deep into injured alveoli. The liposomes were co-decorated with collagen binding peptide (CBP) and collagenase (COL). CBP could help vehicle recognize the pathological collagen and target the fibrotic lungs efficiently because of its high affinity to collagen, and COL assisted in breaking through the collagen barrier and delivering vehicle to the center of injured sites. Then, the released dual drugs developed a synergistic anti-fibrotic effect to repair the damaged epithelium and remodel the extracellular matrix (ECM), thus rebuilding the lung architecture. This study provides a promising strategy to deliver drugs deep into pathological collagen accumulated sites for the enhanced treatment of IPF.

A Humidity-Powered Soft Robot with Fast Rolling Locomotion.

A range of soft robotic systems have recently been developed that use soft, flexible materials and respond to environmental stimulus. The greatest challenge in their design is the integration of the actuator, energy sources, and body of robots while achieving fast locomotion and well-defined programmable trajectories. This work presents such a design that operates under constant conditions without the need for an externally modulated stimulus. By using a humidity-sensitive agarose film and overcoming the isotropic and random bending of the film, the robot, which we call the Hydrollbot, harnesses energy from evaporation for spontaneous and continuous fast self-rolling locomotion with a programmable trajectory in a constant-humidity environment. Moreover, the geometric parameters of the film were fine-tuned to maximize the rolling speed, and the optimised hydrollbot is capable of carrying a payload up to 100% of its own weight. The ability to self-propel fast under constant conditions with programmable trajectories will confer practical advantages to this robot in the applications for sensors, medical robots, actuation, etc.

Lung injury induced by different negative suction pressure in patients with pneumoconiosis undergoing whole lung lavage.

BACKGROUND: Pneumoconiosis is a diffuse interstitial fibronodular lung disease, which is caused by the inhalation of crystalline silica. Whole lung lavage (WLL) is a therapeutic procedure used to treat pneumoconiosis. This study is to compare the effects of different negative pressure suction on lung injury in patients with pneumoconiosis undergoing WLL. MATERIALS AND METHODS: A prospective study was conducted with 24 consecutively pneumoconiosis patients who underwent WLL from March 2020 to July 2020 at Emergency General Hospital, China. The patients were divided into two groups: high negative suction pressure group (group H, n = 13, negative suction pressure of 300-400 mmHg) and low negative suction pressure group (group L, n = 11, negative suction pressure of 40-50 mmHg). The arterial blood gas, lung function, lavage data, oxidative stress, and inflammatory responses to access lung injury were monitored. RESULTS: Compared with those of group H, the right and left lung residual were significantly increased in the group L (P = 0.04, P = 0.01). Potential of hydrogen (pH), arterial partial pressure of oxygen (PaO2), arterial partial pressure of carbon dioxide (PaCO2), lactic acid (LAC) and glucose (GLU) varied from point to point in time (P < 0.01, respectively). There was statistical difference in the trend of superoxide dismutase (SOD) and interleukin-10 (IL-10) over time between the two groups (P < 0.01, P = 0.02). In comparison with the group H, the levels of IL-10 (P = 0.01) and SOD (P < 0.01) in WLL fluid were significantly increased in the group L. There was no statistical difference in the trend of maximal volumtary ventilation (MVV), forced vital capacity (FVC), forced expiratory volume in one second (FEV1%), residual volume (RV), residual volume/total lung capacity (RV/TLC), carbon monoxide dispersion factor (DLCO%), forced expiratory volume in one second/ forced vital capacity (FEV1/FVC%) over time between the two groups (P > 0.05, respectively). CONCLUSION: Low negative suction pressure has the potential benefit to reduce lung injury in patients with pneumoconiosis undergoing WLL, although it can lead to increased residual lavage fluid. Despite differing suction strategies, pulmonary function parameters including FEV1%, RV and DLCO% became worse than before WLL. Trial Registration Chinese Clinical Trial registration number ChiCTR2000031024, 21/03/2020.

Adipose-Derived Stem Cells-Derived Exosomes with High Amounts of Circ_0001747 Alleviate Hypoxia/Reoxygenation-Induced Injury in Myocardial Cells by Targeting MiR-199b-3p/MCL1 Axis.

Recent studies demonstrated that circular RNAs play important roles in exosome-mediated cardio-protective effects after acute myocardial infarction (AMI). A previous study reported that circ_0001747 level is down-regulated in mouse hypoxia/reoxygenation (H/R) injury model. However, its biological role and working mechanism in AMI remain largely unknown.Exosomes were isolated from the culture supernatant of adipose-derived stem cells (ADSCs) using an ExoQuick precipitation kit. We treated mouse myocardial cells HL-1 with H/R to explore the role of exosomal circ_0001747 in AMI pathology. Cell viability, proliferation, apoptosis, and inflammation were analyzed by Cell Counting Kit-8 assay, 5-ethynyl-2'-deoxyuridine assay, flow cytometry, and enzyme-linked immunosorbent assay. Dual-luciferase reporter assay and RNA immunoprecipitation assay were conducted to confirm the interaction between microRNA-199b-3p (miR-199b-3p) and circ_0001747 or MCL1 apoptosis regulator, BCL2 family member (MCL1).H/R-induced HL-1 dysfunction was attenuated by the incubation of exosomes derived from ADSCs, especially the exosomes with high amounts of circ_0001747. Circ_0001747 directly targeted miR-199b-3p in HL-1 cells. miR-199b-3p overexpression partly overturned exosomal circ_0001747-mediated protective effects in H/R-induced HL-1 cells. MCL1 was a direct target of miR-199b-3p in HL-1 cells. miR-199b-3p silencing alleviated H/R-induced damage in HL-1 cells partly by up-regulating MCL1. Circ_0001747 can elevate the messenger RNA and protein levels of MCL1 by sequestering miR-199b-3p.Overall, these results indicated that ADSCs-derived exosomes with high amounts of circ_0001747 attenuated H/R-induced HL-1 dysfunction partly by targeting miR-199b-3p/MCL1 signaling.

Clinical survey of a pedigree with hereditary multiple exostoses and identification of EXT­2 gene deletion mutation.

The aim of the present study was to report a clinical survey of hereditary multiple exostoses (HME) in a large Chinese pedigree, and the identification of a novel deletion mutation of exostosin glycosyltransferase 2 (EXT­2) gene. A patient with multiple exostoses with huge cartilage­capped tumors in scapula, knees and ankles received surgery in Department of Orthopedics (Shanghai Changhai Hospital). A total of 20 family members were recruited to the study, with seven members (five male; two female) diagnosed as HME. The family members of the patients with HME were examined, clinical data and peripheral blood samples were collected, and their DNA was sequenced. The incidence of HME in this family pedigree was 35%. Exostoses were most frequently in the tibiae with occurrence in six patients, followed by ribs, femurs, radii, fibulae, scapulae and humeri. DNA sequencing of peripheral blood revealed a novel deletion mutation, c.824­826delGCA, in exon 5 of the EXT­2 gene, which was observed in all the patients with HME, but not in the healthy family members. Several characteristics of HME in the pedigree were observed, such as susceptibility of male gender, decreased average age of onset and height and increased severity of clinical symptoms with generations.

RHOA inhibits chondrogenic differentiation of mesenchymal stem cells in adolescent idiopathic scoliosis.

PURPOSE: The etiology of adolescent idiopathic scoliosis (AIS) remains unclear. The chondrogenic differentiation of mesenchymal stem cells (MSCs) is important in AIS, and the Ras homolog gene family member A (RHOA) is associated with chondrogenesis. The purpose of this study was to explore the effect of RHOA on the chondrogenic differentiation of MSCs in AIS. METHODS: We isolated MSCs from patients with AIS (AIS MSCs) and individuals without AIS (control MSCs). The inhibitor Y27632 was used to inhibit the function of RHOA/ROCK signaling, and plasmid-based overexpression and siRNA-mediated knockdown were used to manipulate RHOA expression. CCK-8 was used to detect cell viability. The phosphorylation levels of LIMK1, MLC2 and cofilin were detected by Western blotting. The mRNA expression of aggrecan, SOX9, and COL2A1 were confirmed using RT-PCR. Immunofluorescence was used to analyze F-actin and collagen II. Alcian blue staining was performed to assess the secretion of glycosaminoglycans (GAGs). RESULTS: We found that RHOA was significantly upregulated in AIS MSCs, and the phosphorylation levels of LIMK1, MLC2, and cofilin were increased. The mRNA expressions of aggrecan, SOX9, and COL2A1 were notably reduced in AIS MSCs. However, these effects were abolished by Y27632 treatment and RHOA knockdown in AIS MSCs. In addition, RHOA knockdown in AIS MSCs increased the content of collagen II and GAGs. RHOA overexpression in the control MSCs markedly activated the RHOA/ROCK signaling and decreased the expression of aggrecan, SOX9, and COL2A1, F-actin, and GAGs. CONCLUSION: RHOA regulates the chondrogenic differentiation ability of MSCs in AIS via the RHOA/ROCK signaling pathway and this regulation may involve SOX9.