VP2 mediates the release of the feline calicivirus RNA genome by puncturing the endosome membrane of infected cells.

Feline calicivirus (FCV) is one of the few members of the Caliciviridae family that grows well in cell lines and, therefore, serves as a surrogate to study the biology of other viruses in the family. Conley et al. (14) demonstrated that upon the receptor engagement to the capsid, FCV VP2 forms a portal-like assembly, which might provide a channel for RNA release. However, the process of calicivirus RNA release is not yet fully understood. Our findings suggest that the separation of the FCV capsid from its genome RNA (gRNA) occurs rapidly in the early endosomes of infected cells. Using a liposome model decorated with the FCV cell receptor fJAM-A, we demonstrate that FCV releases its gRNA into the liposomes by penetrating membranes under low pH conditions. Furthermore, we found that VP2, which is rich in hydrophobic residues at its N-terminus, functions as the pore-forming protein. When we substituted the VP2 N-terminal hydrophobic residues, the gRNA release efficacy of the FCV mutants decreased. In conclusion, our results suggest that in the acidic environment of early endosomes, FCV VP2 functions as the pore-forming protein to mediate gRNA release into the cytoplasm of infected cells. This provides insight into the mechanism of calicivirus genome release.IMPORTANCEResearch on the biology and pathogenicity of certain caliciviruses, such as Norovirus and Sapovirus, is hindered by the lack of easy-to-use cell culture system. Feline calicivirus (FCV), which grows effectively in cell lines, is used as a substitute. At present, there is limited understanding of the genome release mechanism in caliciviruses. Our findings suggest that FCV uses VP2 to pierce the endosome membrane for genome release and provide new insights into the calicivirus gRNA release mechanism.

Efficacy of meniscus suture absorbability on meniscus healing success rate via second-look arthroscopy after meniscal repair: a systematic review and meta-analysis.

BACKGROUND: To preserve the meniscus's function, repairing the torn meniscus has become a common understanding. After which, the search for the ideal suture material is continuous. However, it is still controversial about the efficacy of suture absorbability on meniscus healing. METHODS: This review is designed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. INCLUSION CRITERIA: (1) Studies on meniscus repair; (2) Second-look arthroscopy was performed; (3) The meniscus was repaired by absorbable and non-absorbable sutures; (4) The healing condition of repaired meniscus via second-look arthroscopy was described. EXCLUSION CRITERIA: (1) Animal studies, cadaveric studies, or in vitro research; (2) Meniscus transplantation; (3) Open meniscus repair; (4) Reviews, meta-analysis, case reports, letters, and comments; (5) non-English studies. MEDLINE, Embase, and Cochrane Database were searched up to October 2022. Risk of bias and methodology quality of included literature were assessed according to ROBINS-I and the modified Coleman Methodological Scale (MCMS). Descriptive analysis was performed, and meta-analysis was completed by RevMan5.4.1. RESULTS: Four studies were included in the systematic review. Among them, three studies were brought into the meta-analysis, including 1 cohort study and 2 case series studies about 130 patients with meniscal tears combined with anterior cruciate ligament injury. Forty-two cases were repaired by absorbable sutures, and 88 were repaired by non-absorbable sutures. Using the fixed effect model, there was a statistical difference in the healing success rate between the absorbable and the non-absorbable groups [RR1.20, 95%CI (1.03, 1.40)]. CONCLUSION: In early and limited studies, insufficient evidence supports that non-absorbable sutures in meniscus repair surgery could improve meniscal healing success rate under second-look arthroscopy compared with absorbable sutures. In contrast, available data suggest that absorbable sutures have an advantage in meniscal healing. TRIAL REGISTRATION: The review was registered in the PROSPERO System Review International Pre-Registration System (Registration number CRD42021283739).

Production and application of mouse monoclonal antibodies targeting linear epitopes in pB602L of African swine fever virus.

African swine fever (ASF) is an acute hemorrhagic disease of domestic pigs. The causative agent of ASF, ASF virus (ASFV), is a double-stranded DNA virus, the sole member in the family Asfarviridae. The non-structural protein pB602L of ASFV is a molecular chaperone of the major capsid protein p72 and plays a key role in icosahedral capsid assembly. This protein is antigenic and is a target for developing diagnostic tools for ASF. To generate monoclonal antibodies (mAbs) against pB602L, a prokaryotically expressed recombinant pB602L protein was produced, purified, and used as an antigen to immunize mice. A total of eight mouse mAbs were obtained, and their binding epitopes were screened by Western blot using an overlapping set of polypeptides from pB602L. Three linear epitopes were identified and designated epitope 1 (366ANRERYNY373), epitope 2 (415GPDAPGLSI423), and epitope 3 (498EMLNVPDD505). Based on the epitope recognized, the eight mAbs were placed into three groups: group 1 (B2A1, B2F1, and B2D10), group 2 (B2H10, B2B2, B2D8, and B2A3), and group 3 (B2E12). The mAbs B2A1, B2H10, and B2E12, each representing one of the groups, were used to detect pB602L in ASFV-infected porcine alveolar macrophages (PAMs) and pig tissues, using an indirect fluorescence assay (IFA) and immunohistochemical staining, respectively. The results showed that pB602L was detectable with all three mAbs in immunohistochemical staining, but only B2H10 was suitable for detecting the proteins in ASFV-infected PAMs by IFA. In summary, we developed eight anti-pB602L mouse mAbs recognizing three linear epitopes in the protein, which can be used as reagents for basic and applied research on ASFV.

Tranexamic acid is beneficial for blood management of high tibial osteotomy: a randomized controlled study.

INTRODUCTION: The purpose of this study was to investigate whether TXA can effectively reduce blood loss after HTO and related complications and to evaluate its safety. MATERIALS AND METHODS: From March 2016 to March 2018, 100 patients who underwent medial opening wedge HTO in the Department of Orthopedics, the second affiliated hospital of xi'an jiaotong university, with an average age of 52.8 ± 3.2 years, were randomly divided into the TXA group (using intravenous TXA) and the control group (using the same amount of normal saline), with 50 patients in each group. The postoperative wound drainage volume, decrease in hemoglobin and hematocrit value, total blood loss, wound healing, blood transfusion, deep venous thrombosis (DVT) and pulmonary embolism (PE) were compared between the two groups. RESULTS: The drainage volume on the first postoperative day and the total drainage volume of the TXA group were significantly lower compared with those of the control group (145.7 vs 264.5 ml, 282.3 vs 413.2 ml, P < 0.05). The decreases in the hemoglobin and hematocrit values on the postoperative first, second and fifth days were lower in the TXA group than those in the control group (1.4 VS 3.5, 2.6 vs 3.3, 1.9 vs 2.9 g, P < 0.05; 3.3 vs 5.5, 5.0 vs 9.1, 3.8 vs 7.2%, P < 0.05), and the mean total blood loss was also lower in the TXA group than that in the control group (477.9 vs 834.6 ml, P < 0.05). In the control group, 1 patient had wound hematoma requiring additional paracentesis and pressure dressing, 1 patient had superficial wound infection requiring additional debridement, and 1 patient had postoperative blood transfusion compared to none in the TXA group (P > 0.05). There was no symptomatic DVT or PE in either of the groups. CONCLUSION: Intravenous TXA can effectively and safely reduce blood loss and bleeding-related complications after HTO and was beneficial for the blood management of HTO.

The modified cross-suture technique for unilateral pulled-out anchor during all-inside meniscal repair.

BACKGROUND: Meniscal repair has received increasing attention, but for inexperienced doctors, unilateral suture anchor pulling out may occur during all-inside meniscal repair, and the treatment outcome may be affected. When the errors happened intraoperatively, how to minimize the loss under guaranteeing of treatment effectiveness is a topic worth studying. PURPOSE: To explore the practicability and effectiveness of the modified cross-suture method for arthroscopic remediation of unilateral suture anchor pulling out of an all-inside meniscal repair system. METHODS: From May 2014 to May 2017, 28 patients diagnosed with injuries of the meniscus and anterior cruciate ligaments (ACL) from the First Department of Orthopaedics of the Second Affiliated Hospital of Xi'an Jiaotong University were enrolled in the study as the observation group, including 18 males and 10 females with an average age of 25.5 ± 2.3 years (range 18-42 years). All patients underwent ACL reconstruction concurrently. All meniscus injuries were repaired with an all-inside meniscal repair technique, and 1-3 needles of unilateral suture anchor pulling out occurred intraoperatively. The modified cross-suture method was used to remedy the error of anchor pulling out and to eventually complete an effective repair. Another 30 patients who underwent ACL reconstruction and all-inside meniscal concurrently without unilateral suture anchor pulling out, including 20 males and 10 females with an average age of 26.3 ± 1.9 years (range 19-45 years), were enrolled as the control group. During postoperative follow-up, range of motion, Lachman test and pivot shift test were performed during the physical examination. The clinical healing of the meniscus was evaluated according to the Barrett standard. The meniscus healing status was also confirmed with magnetic resonance imaging (MRI). The function of the knee joint was evaluated according to the IKDC, Lysholm and Tegner scores. RESULTS: Twenty-five patients in the observation group and 28 patients in the control group completed the follow-up, with an average follow-up of 18.4 ± 5.2 months. All operations were performed by the same surgeon. At the follow-up 1 year after the operation, the average knee ROM of the two groups was 125.2 ± 4.3 degrees and 124.7 ± 3.8 degrees, the clinical healing rate of the meniscus of the two groups was 92.0% (23/25) and 92.9% (26/28), the MRI healing rate of the menniscus of the two groups was 72.0% (18/25) and 71.4% (20/28), and the IKDC, Lysholm and Tegner scores of the two groups were 90.52 ± 2.8, 89.17 ± 3.1, and 6.81 ± 1.7 and 91.42 ± 1.9, 90.32 ± 3.4, and 7.02 ± 1.4, respectively. The differences were not statistically significant (P > 0.05). CONCLUSIONS: The modified cross-suture method is practicable and effective for arthroscopic remediation of unilateral suture anchor pulling out in an all-inside meniscal repair system.

A Method of Accurate Bone Tunnel Placement for Anterior Cruciate Ligament Reconstruction Based on 3-Dimensional Printing Technology: A Cadaveric Study.

PURPOSE: To explore a method of bone tunnel placement for anterior cruciate ligament (ACL) reconstruction based on 3-dimensional (3D) printing technology and to assess its accuracy. METHODS: Twenty human cadaveric knees were scanned by thin-layer computed tomography (CT). To obtain data on bones used to establish a knee joint model by computer software, customized bone anchors were installed before CT. The reference point was determined at the femoral and tibial footprint areas of the ACL. The site and direction of the bone tunnels of the femur and tibia were designed and calibrated on the knee joint model according to the reference point. The resin template was designed and printed by 3D printing. Placement of the bone tunnels was accomplished by use of templates, and the cadaveric knees were scanned again to compare the concordance of the internal opening of the bone tunnels and reference points. RESULTS: The twenty 3D printing templates were designed and printed successfully. CT data analysis between the planned and actual drilled tunnel positions showed mean deviations of 0.57 mm (range, 0-1.5 mm; standard deviation, 0.42 mm) at the femur and 0.58 mm (range, 0-1.5 mm; standard deviation, 0.47 mm) at the tibia. CONCLUSIONS: The accuracy of bone tunnel placement for ACL reconstruction in cadaveric adult knees based on 3D printing technology is high. CLINICAL RELEVANCE: This method can improve the accuracy of bone tunnel placement for ACL reconstruction in clinical sports medicine.

Beneficial effect of grape seed proanthocyanidin extract in rabbits with steroid-induced osteonecrosis via protecting against oxidative stress and apoptosis.

BACKGROUND: Oxidative damage and apoptosis play dominant roles in the pathogenesis of steroid-induced osteonecrosis (ON). Grape seed proanthocyanidin extract (GSPE) demonstrates antioxidant and antiapoptotic properties. Our aim was to demonstrate the effects of GSPE in preventing steroid-induced ON in rabbits. METHODS: Osteonecrosis was induced by high-dose methylprednisolone (40 mg/kg). Rabbits in the preventive medicine group were treated with 100 mg/kg/day GSPE for 14 consecutive days, and the presence or absence of ON was examined histopathologically. Oxidative damage in bone tissue was assessed by immunohistochemical staining of 8-oxo-2'-deoxyguanosine (8-OHdG), malondialdehyde (MDA) levels, and activities of antioxidant enzymes Cu/Zn superoxide dismutase (SOD) and phospholipid hydroperoxide glutathione peroxidase (GSH-Px). Apoptosis was detected via quantitative terminal deoxynucleotidyl transferase (TdT) deoxyuridine triphosphate nick end labelling (TUNEL) staining and activated caspase 3 immunoblotting and activity. RESULTS: GSPE significantly attenuated the changes of immunohistochemical staining of 8-OHdG, MDA levels, and antioxidant enzymes activities, which were caused by methylprednisolone administration. Quantitative TUNEL and caspase 3 assay showed lower apoptosis with GSPE application. Simultaneously, GSPE reduced the incidence of steroid-induced ON in an established rabbit model to 17.6 %, compared with 87.5 % in the steroid-only group. CONCLUSION: These results reveal that GSPE treatment could inhibit oxidative damage and apoptosis to exert beneficial effects on reducing the incidence of steroid-induced ON in rabbit models.

Association of toll-like receptor 4 signaling pathway with steroid-induced femoral head osteonecrosis in rats.

Osteonecrosis of the femoral head is frequently observed in patients treated with excessive corticosteroids. However, the pathogenesis of corticosteroid-induced osteonecrosis remains unclear. The purpose of this study was to investigate the role of Toll-like receptor 4 (TLR4) signaling pathway in steroid-induced femoral head osteonecrosis in rats. Male Sprague-Dawley rats were injected intramuscularly with 20 mg/kg methylprednisolone (MP) for 8 weeks, twice per week. The animals were sacrificed at 2, 4 and 8 weeks after the last MP injection, respectively, and then allocated to the 2-, 4- and 8-week model groups (n=24 each). Rats in the control group (n=12) were not given any treatment. Histopathological analysis was performed and the concentration of tartrate-resistant acid phosphatase (TRAP) in plasma was determined. The activation of osteoclasts in the femoral head was assessed by TRAP staining. The expression of TLR4, MyD88, TRAF6 and NF-κB p65 that are involved in TLR4 signaling, and MCP-1 production were detected by using real-time PCR (RT-PCR) and Western blotting. The results showed that the osteonecrosis in the femoral head was clearly observed and the concentration of TRAP in the plasma was increased in the model rats. The femoral head tissues in MP-treated rats were positive for TRAP and the intensity of TRAP staining was greater in MP-treated rats than in control rats. As compared with the control group, the mRNA expression of TLR4 signaling-related factors was enhanced significantly at 4 and 8 weeks, and the protein levels of these factors increased significantly with time. It was concluded that MP could induce the femoral head osteonecrosis in rats, which was associated with osteoclast activation via the TLR4 signaling pathway. These findings suggest that TLR4 signaling pathway plays a pivotal role in the pathogenesis of steroid-induced osteonecrosis.

Arthroscopic Autologous Iliac Bone Grafting With Double-Row Elastic Fixation and Double Antirotating Anchors for Recurrent Anterior Shoulder Dislocation With Massive Glenoid Bone Defect.

The management of recurrent anterior shoulder dislocations with massive glenoid bone defects typically involves arthroscopic intervention. Autologous iliac bone grafting with double-row elastic fixation reportedly yields excellent outcomes. In this article, we introduce a specialized technique for iliac bone grafting that uses double-row elastic fixation and double antirotating anchors. Implementation of this technique prevents the occurrence of iliac graft rotation.

Intramedullary core decompression combined with endoscopic intracapsular decompression and debridement for pre-collapse non-traumatic osteonecrosis of the femoral head.

BACKGROUND: The effect of core decompression on the treatment of pre-collapse non-traumatic osteonecrosis of the femoral head (ONFH) is still limited. This study aimed to explore the efficacy of core decompression combined with intra-articular decompression (debridement of the hip joint and incision of the hip capsule) under hip arthroscopic guidance in patients with pre-collapse ONFH. METHODS: The clinical data of 101 patients with pre-collapse ONFH were analysed retrospectively. Sixty patients (80 hips) received small-diameter multi-channel core decompression alone in first half review period (group B). Forty-one patients (59 hips) were treated with small-diameter multi-channel core decompression combined with intra-articular decompression under hip arthroscopy guidance in second half review period (group A). The surgical duration; intraoperative bleeding; intra-articular pressure(IAP) before and after surgery; length of hospital stay; hospitalisation expenses; visual analogue scale (VAS) score before, 1 week, 4 weeks, 3 months and 1 year after surgery; and Harris score of the hip joint before, 3 months and 1 year after surgery were recorded and compared between group A and group B. X-ray examination was performed every month to observe the collapse of the femoral head within 2 years after surgery, which was compared using the Kaplan-Meier survival curve analysis. RESULTS: When the two groups were compared, the surgical duration was longer and hospitalisation expenses were higher in group A than in group B (P < 0.05). However, the VAS score and the Harris score of the hip joint after surgery improved significantly compared with those before surgery (P < 0.05), which were more apparent in group A than in group B (P < 0.05). X-ray examination revealed that 6 hips in group A and 22 in group B received femoral head collapse at the 2-year follow-up. The survival rate of the femoral head in group A was significantly higher than that in group B (P < 0.05). CONCLUSION: Small-diameter multi-channel core decompression combined with intra-articular decompression (debridement of the hip joint and incision of the hip capsule) under hip arthroscopic guidance for treating early ONFH can more effectively alleviate joint pain, improve joint function and delay ONFH progression.

Addition of Tibial Tubercle Osteotomy to Combined MPFL Reconstruction and Lateral Retinacular Release not Recommended for Recurrent Patellar Dislocation in Patients with 15 to 20 mm TT-TG.

Surgery is the primary treatment for recurrent patellar dislocation. However, there is still a lack of consensus regarding the choice of combined surgical methods due to the complexity of the anatomical factors. This study aimed to investigate the efficacy and radiological changes in medial patellofemoral ligament reconstruction (MPFLR) and lateral retinacular release (LRR) with and without tibial tubercle osteotomy (TTO) for recurrent patellar dislocation in patients with a tibial tubercle-trochlear groove (TT-TG) distance of 15 to 20 mm. Fifty-four patients were enrolled in this retrospective study between 2010 and 2014. The average patient age was 21.6 ± 5.0 years. All patients underwent MPFLR and LRR, and in 18 patients, these procedures were combined with TTO. Patients were evaluated preoperatively and postoperatively for patellar lateral shift, patellar tilt angle, TT-TG distance, Q-angle, Caton-Deschamps index (CDI), Kujala, and Lysholm scores. The minimally clinical important difference was used to compare clinical outcomes between two groups. In the mean follow-up of 82.6 ± 15.9 months, functional scores improved significantly in both groups (p < 0.01). There were no significant differences in postoperative function scores between the two groups (Kujala, p = 0.25, mean difference = 1.5, 95% confidence interval [CI]: -1.4-4.4; Lysholm, p = 0.76, mean difference = -0.6, 95% CI: -5.9-4.7). Additionally, TTO significantly decreased Q-angle (23.6 ± 2.4 vs. 17.4 ± 2.9, p < 0.01), TT-TG (17.1 ± 1.5 vs. 10.4 ± 1.8, p < 0.01), and CDI (1.18 ± 0.12 vs. 1.08 ± 0.07, p < 0.01). Combined MPFLR and LRR with and without TTO are both effective techniques for recurrent patellar dislocation. Additional osteotomy can correct patellar alta and tibial tubercle lateralization. However, given that there were no significant differences in postoperative functional scores or recurrence rate between groups, we may not recommend TTO in addition to MPFLR and LRR in patients with TT-TG of 15 to 20 mm. Long-term and prospective cohort studies are required to assess further outcomes.

Metavirome Analysis Reveals a High Prevalence of Porcine Hemagglutination Encephalomyelitis Virus in Clinically Healthy Pigs in China.

Six swine coronaviruses (SCoVs), which include porcine epidemic diarrhea virus (PEDV), transmissible gastroenteritis virus (TGEV), porcine hemagglutination encephalomyelitis virus (PHEV), porcine respiratory coronavirus (PRCV), swine acute diarrhea syndrome coronavirus (SADS-CoV), and porcine delta coronavirus (PDCoV), have been reported as infecting and causing serious diseases in pigs. To investigate the genetic diversity and spatial distribution of SCoVs in clinically healthy pigs in China, we collected 6400 nasal swabs and 1245 serum samples from clinically healthy pigs at slaughterhouses in 13 provinces in 2017 and pooled them into 17 libraries by type and region for next-generation sequencing (NGS) and metavirome analyses. In total, we identified five species of SCoVs, including PEDV, PDCoV, PHEV, PRCV, and TGEV. Strikingly, PHEV was detected from all the samples in high abundance and its genome sequences accounted for 75.28% of all coronaviruses, while those belonging to TGEV (including PRCV), PEDV, and PDCoV were 20.4%, 2.66%, and 2.37%, respectively. The phylogenetic analysis showed that two lineages of PHEV have been circulating in pig populations in China. We also recognized two PRCVs which lack 672 nucleotides at the N-terminus of the S gene compared with that of TGEV. Together, we disclose preliminarily the genetic diversities of SCoVs in clinically healthy pigs in China and provide new insights into two SCoVs, PHEV and PRCV, that have been somewhat overlooked in previous studies in China.

Effect of different bone cement distributions in percutaneous kyphoplasty on clinical outcomes for osteoporotic vertebral compression fractures: A retrospective study.

Osteoporotic fractures and their complications are becoming increasingly harmful to the elderly. This study aimed to evaluate the clinical results of connected or unconnected bilateral cement after bilateral percutaneous kyphoplasty (PKP) in patients with osteoporotic vertebral compression fractures (OVCF). The clinical data of 217 patients with single-segment OVCF were retrospectively collected. Patients were allocated into 2 groups according to the bilateral bone cement in the vertebrae was connected or unconnected after surgery. The surgery-related indexes of the 2 groups were compared, including operation time; bone cement injection volume; contact situation between bone cement and the upper and lower endplates of the vertebral body; visual analogue scale (VAS) scores before surgery, 1 week and 1 year after surgery; Oswestry disability index (ODI) before surgery, 1 week and 1 year after surgery; local kyphosis angle (LKA) before surgery, 1 week and 1 year after surgery; postoperative vertebral body height at 1 week and 1 year after surgery; vertebral body height restoration rate (HRR) at 1 week and 1 year after surgery. The follow-up results of all patients were recorded. The postoperative VAS, ODI, vertebral body height, LKA and other indexes of the 2 groups were significantly improved compared with those before the operation (P < .05), and there was no significant difference between the 2 groups (P > .05). At the same time, there were no significant difference in vertebral body HRR and bone cement leakage rate between the 2 groups (P > .05). X-ray examination showed that 21 of 217 patients (21/217, 9.8%) had a refracture of the injured vertebral body, including 16 cases (16/121, 13.2%) in the unconnected group and 5 cases (5/96, 5.2%) in the connected group (P < .05). Adjacent vertebrae fractures occurred in 25 cases (25/217, 11.5%), while 19 cases (19/121, 15.7%) were in the unconnected group and 6 cases (6/96, 6.3%) were in the connected group (P < .05). PKP has a good therapeutic effect on OVCF no matter whether the bilateral bone cement is connected or not. However, if the bilateral cement inside the vertebra was connected, the risk of recollapse of the injured vertebrae and the new fracture of adjacent vertebrae could be reduced.

Spatio-temporal spread and evolution of influenza A (H7N9) viruses.

The influenza A (H7N9) virus has been seriously concerned for its potential to cause an influenza pandemic. To understand the spread and evolution process of the virus, a spatial and temporal Bayesian evolutionary analysis was conducted on 2,052 H7N9 viruses isolated during 2013 and 2018. It revealed that the H7N9 virus was probably emerged in a border area of Anhui Province in August 2012, approximately 6 months earlier than the first human case reported. Two major epicenters had been developed in the Yangtze River Delta and Peral River Delta regions by the end of 2013, and from where the viruses have also spread to other regions at an average speed of 6.57 km/d. At least 24 genotypes showing have been developed and each of them showed a distinct spatio-temporal distribution pattern. Furthermore, A random forest algorithm-based model has been developed to predict the occurrence risk of H7N9 virus. The model has a high overall forecasting precision (> 97%) and the monthly H7N9 occurrence risk for each county of China was predicted. These findings provide new insights for a comprehensive understanding of the origin, evolution, and occurrence risk of H7N9 virus. Moreover, our study also lays a theoretical basis for conducting risk-based surveillance and prevention of the disease.

Hoffa's fracture in a five-year-old child diagnosed and treated with the assistance of arthroscopy: A case report.

BACKGROUND: Hoffa's fracture is a coronal-oriented fracture of the femoral condyle. It is rarely observed in pediatric patients that isolated coronal fracture of the medial femoral condyle accompanies an intact lateral femoral condyle. Only a few cases involving Hoffa's fracture of the medial femoral condyle have been reported in patients with undeveloped skeletons. Such a fracture cannot be observed by routine imaging examinations, thus resulting in possible misdiagnosis and further treatment challenges. CASE SUMMARY: A 5-year-old boy with Hoffa's fracture of the medial femoral condyle suffered from right knee pain and severe swelling after being hit by a heavy object. The patient was misdiagnosed and initially treated in a local primary healthcare center. No improvement in his right knee's extension was observed following conservative treatment for 2 wk. The patient was transferred to our hospital, re-diagnosed using arthroscopy, and underwent open reduction and internal fixation. The therapeutic outcome was satisfactory with the screws removed 7 mo after fixation. At the final follow-up of 40 mo, the range of motion in the knee had recovered. There was no varus-valgus instability. CONCLUSION: Hoffa's fracture is rarely seen in children aged 5 years, let alone in the medial condyle, and can easily be misdiagnosed due to limited physical and imaging examinations. Suspected Hoffa's fracture in preschool children should be confirmed based on arthroscopic findings. Open reduction and internal fixation should be performed to protect the articular surface and prevent long-term complications.

Structural Insights into Alphavirus Assembly Revealed by the Cryo-EM Structure of Getah Virus.

Getah virus (GETV) is a member of the alphavirus genus, and it infects a variety of animal species, including horses, pigs, cattle, and foxes. Human infection with this virus has also been reported. The structure of GETV has not yet been determined. In this study, we report the cryo-EM structure of GETV at a resolution of 3.5 Å. This structure reveals conformational polymorphism of the envelope glycoproteins E1 and E2 at icosahedral 3-fold and quasi-3-fold axes, which is believed to be a necessary organization in forming a curvature surface of virions. In our density map, three extra densities are identified, one of which is believed a "pocket factor"; the other two are located by domain D of E2, and they may maintain the stability of E1/E2 heterodimers. We also identify three N-glycosylations at E1 N141, E2 N200, and E2 N262, which might be associated with receptor binding and membrane fusion. The resolving of the structure of GETV provides new insights into the structure and assembly of alphaviruses and lays a basis for studying the differences of biology and pathogenicity between arthritogenic and encephalitic alphaviruses.

Tetramethylpyrazine protects spinal cord and reduces inflammation in a rat model of spinal cord ischemia-reperfusion injury.

OBJECTIVE: Inflammation, which is known to be detrimental to the neurologic outcome during the acute phase after an ischemic stroke, provides a potential target for preventive or therapeutic approach for spinal cord ischemia-reperfusion injury. Tetramethylpyrazine (TMP), a pure compound derived from Ligusticum chuanxiong, is widely used in the treatment of ischemic stroke. The present study aimed to gain a deeper insight into the mechanism underlying the anti-inflammatory effects of TMP on spinal cord ischemia-reperfusion injury. METHODS: Spinal cord ischemia was induced in male Sprague-Dawley rats by balloon occlusion of the thoracic aorta. The experimental groups (n = 30 per group) included sham operation, control (receiving only normal saline), and TMP (30 mg/kg, 30 minutes before occlusion). Neurologic function was assessed by the Basso, Beattie, and Bresnahan (BBB) score at 1, 6, 12, 24, and 48 hours after reperfusion. Histologic changes were studied using Nissl staining. Infarct volume was analyzed using 2,3,5-triphenyltetrazolium chloride staining. Myeloperoxidase (MPO) activity was determined by using a rat MPO assay kit. Interleukin (IL)-1ß, tumor necrosis factor (TNF)-α, IL-10 and nuclear factor (NF)-κB were examined with immunohistochemistry, enzyme-linked immunosorbent assay (ELISA) and Western blotting. RESULTS: Compared with the control group, the TMP group showed significantly improved neurologic outcome (P < .05), decreased infarct volume (42.3% vs 17.4%), and alleviated neutrophil infiltration (0.35 vs 0.18 U/g). TMP treatment reduced the expressions of proinflammatory cytokines TNF-α (28.62 vs 15.23 pg/mg protein) and IL-1ß (13.62 vs 8.24 pg/mg protein), upregulated the expression of anti-inflammatory cytokine IL-10 (18.35 vs 31.26 pg/mg protein), and inhibited the activation of NF-κB (2.78 vs 1.22) in ischemic spinal cord. CONCLUSIONS: Treatment with TMP exerted a neuroprotective effect against spinal cord ischemia-reperfusion injury. The anti-inflammatory effect was believed to be one of the contributing mechanisms.

Hydroxysafflor yellow A protects PC12 cells against the apoptosis induced by oxygen and glucose deprivation.

Hydroxysafflor yellow A (HSYA) was reported neuroprotective under several ischemic models in vivo. In this study, the direct effect of HSYA against oxygen-glucose deprivation (OGD) inducing acute neuronal injury and the underling mechanisms in vitro were investigated. Four-hour oxygen and glucose deprivation (OGD) followed by 20 h reperfusion (adding back oxygen and glucose, OGD-R) was used to induce in vitro ischemia reperfusion injury in differentiated rat pheochromocytoma PC12 cells. HSYA (1, 10, and 100 µmol/l) was added to the cultures 30 min prior to the ischemic insult and was present during OGD and reoxygenation phases. The survival rate of PC12 cells was detected by MTT assay. The contents of malondialdehyde (MDA), superoxide dismutase (SOD) activity were elevated by biochemical method. Hoechst 33258 staining and flow cytometric analysis were used to detect apoptosis; western blotting was used to detect the expression of Bcl-2, Bax, and Cytochrome C protein. The activity of caspase-3 was assessed by colorimetry. HSYA concentration-dependently attenuated neuronal damage with characteristics of increasing injured neuronal absorbance of MTT, decreasing cell apoptosis, and antagonizing decreases in SOD activity and increase in MDA level induced by OGD-R. Moreover, the down-regulation of Bcl-2, up-regulation of Bax and the release of mitochondrial cytochrome c to cytosol and the consequent activation of caspase-3 were reversed by HSYA in a dose-dependent manner. These results suggest that apoptosis is an important characteristic of OGD-R-induced PC 12 death and that treatment of PC12 cells with HSYA can block OGD-R-induced apoptosis through suppression of intracellular oxidative stress and mitochondria dependent caspase cascade.

Mettl14-mediated m6A modification modulates neuron apoptosis during the repair of spinal cord injury by regulating the transformation from pri-mir-375 to miR-375.

BACKGROUND: Spinal cord injury (SCI) is a disabling disorder, resulting in neurological impairments. This study investigated the mechanism of methyltransferase-like 14 (Mettl14) on apoptosis of spinal cord neurons during SCI repair by mediating pri-microRNA (miR) dependent N6-methyladenosine (m6A) methylation. METHODS: The m6A content in total RNA and Mettl14 levels in spinal cord tissues of SCI rats were detected. Mettl14 expression was intervened in SCI rats to examine motor function, neuron apoptosis, and recovery of neurites. The cell model of SCI was established and intervened with Mettl14. miR-375, related to SCI and positively related to Mettl14, was screened out. The expression of miR-375 and pri-miR-375 after Mettl14 intervention was detected. The expression of pri-miR-375 combined with DiGeorge critical region 8 (DGCR8) and that modified by m6A was detected. Furthermore, the possible downstream gene and pathway of miR-375 were analysed. SCI cell model with Mettl14 intervention was combined with Ras-related dexamethasone-induced 1 (RASD1)/miR-375 intervention to observe the apoptosis. RESULTS: Mettl14 level and m6A content in spinal cord tissue were significantly increased. After Mettl14 knockdown, the injured motor function was restored and neuron apoptosis was reduced. In vitro, Mettl14 silencing reduced the apoptosis of SCI cells; miR-375 was reduced and pri-miR-375 was increased; miR-375 targeted RASD1. Silencing Mettl14 inactivated the mTOR pathway. The apoptosis in cells treated with silencing Mettl14 + RASD1/miR-375 was inhibited. CONCLUSIONS: Mettl14-mediated m6A modification inhibited RASD1 and induced the apoptosis of spinal cord neurons in SCI by promoting the transformation of pri-miR-375 to mature miR-375.