Monoaxial Screws Versus Polyaxial Screws Osteosynthesis for Unstable Atlas Fractures: A Retrospective, Comparative Study With a Minimum Follow-Up of 3 years.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: The study aimed to compare the radiological parameters, clinical outcomes, and long-term effects of the posterior osteosynthesis with polyaxial screw-rod system and the monoaxial screw-rod system in the treatment of unstable atlas fractures. METHODS: We retrospectively analyzed the clinical data of 33 patients with posterior ORIF for unstable atlas fractures in our hospital from August 2013 to June 2020, with a minimum of 3 years of follow-up. Polyaxial screws (group A) were used in 12 patients and monoaxial screws (group B) in 21 patients. Perioperative data, radiological parameters, and clinical outcomes were collected and compared between the 2 surgical approaches. RESULTS: The operative time, blood loss, time of screw-rod system placement, and hospital stay were significantly lower in group A than in group B. At the last follow-up, the visual analog scale (VAS) score and anterior arch reduction rate of the atlas in group A were lower than those in group B, while the lateral mass displacement (LMD) in group A was higher than that in group B. There was no significant difference between Group A and Group B in terms of the anterior atlantodental interval (AADI), posterior arch reduction rate of the atlas, range of motion (ROM), and neck disability index (NDI). CONCLUSIONS: Monoaxial screws can achieve better reduction results for unstable atlas fractures, especially for the anterior arch of atlas. However, the surgical operation of monoaxial screws is more complicated than that of polyaxial screws and has more complications. Appropriate implants should be selected for the treatment of unstable atlas fractures based on the type of atlas fracture, the experience of surgeons, and the demands of patients.

Direct osteosynthesis in the treatment of atlas burst fractures: a systematic review.

PURPOSE: The treatment of unstable atlas fractures remains a controversial topic. The study aims at assessing the prognosis and efficacy of osteosynthesis for unstable atlas fractures through a review of the current literature and additionally aims to compare outcomes between the transoral and posterior approaches. METHODS: A systematic review of databases including PubMed, EMBASE, Cochrane, Web of Science, CNKI, and Wanfang was conducted. Titles and abstracts were screened by two reviewers to identify studies meeting pre-defined inclusion criteria for comprehensive analysis. RESULTS: The systematic review included 28 articles, 19 employing the posterior approach and 9 utilizing the transoral approach. It covered osteosynthesis in 297 patients with unstable atlas fractures, comprising 169 treated via the posterior approach and 128 via the transoral approach. Analysis revealed high healing rates and clinical improvement in both approaches, evidenced by improvements in the visual analog scale, range of motion, atlantodens interval, and lateral displacement distance post-surgery. CONCLUSION: Osteosynthesis offers effective treatment for unstable atlas fractures. Both transoral and posterior approaches can achieve good clinical outcomes for fracture, and biomechanical studies have confirmed that osteosynthesis can maintain the stability of the occipitocervical region, preserve the motor function of the atlantoaxial and occipito-atlantoaxial joints, and greatly improve the quality of life of patients. However, variations exist in the indications and surgical risks associated with each method, necessitating their selection based on a thorough clinical evaluation of the patient's condition.

Design of a novel lateral mass screw-plate system for the treatment of unstable atlas fractures: a finite element analysis.

BACKGROUND: Osteosynthesis of unstable atlas fractures preserves joint motion and therefore has a distinct advantage over a range of treatment procedures. To prevent the potential disadvantages associated with osteosynthesis, a new atlas lateral mass screw-plate (LMSP) system has been designed. However, the biomechanical role of using the LMSP system in atlas internal fixation is not known. The aim of this study was to compare the biomechanical stability of a new LMSP with traditional posterior screw and rod (PSR) fixation techniques on the occipitocervical junction (C0-C2) through finite element analysis. METHODS: A nonlinear C0-C2 finite element model of the intact upper cervical spine was developed and validated. The unstable model using the PSR system was then compared with the model using the LMSP system for fixation. A vertical load of 40 N was applied to the C0 to simulate head weight, while a torque of 1.5 Nm was applied to the C0 to simulate flexion, extension, lateral bending, and axial rotation. RESULTS: The range of motion of both systems was close to the intact model. Compared with the LMSP system model, the PSR system model increased flexion, extension, lateral bending, and axial rotation by 4.9%, 3.0%, 5.0%, and 29.5% in the C0-C1 segments, and 4.9%, 2.7%, 2.4%, and 22.6% in the C1-C2, respectively. In flexion, extension, and lateral bending motion, the LMSP system model exhibited similar stress to the PSR system model, while in axial rotation, the PSR system model exhibited higher stress. CONCLUSIONS: The findings of our study indicate that the two tested system models provide comparable stability. However, better stability was achieved during axial rotation with the LMSP system, and in this system, the maximum von Mises stress was less than that of the PSR one. As the atlantoaxial joint functions primarily as a rotational joint, the use of the LMSP system may provide a more stable environment for the joint that has become unstable due to fracture.

Design and preparation of naringenin loaded functional biomimetic nano-drug delivery system for Alzheimer's disease.

Efficient brain drug delivery has been a challenge in the treatment of Alzheimer's Disease and other brain disorders as blood-brain barrier (BBB) impedes most drugs to reach brain. To overcome this obstacle, we developed a novel TGN decorated erythrocyte membrane-coated poly (lactic-co-glycolic acid) nanoparticle (TRNNs). The nanoparticle significantly boosted the penetration (7.3 times) in a U-118MG and HCMEC/D3 cell co-culture BBB model in vitro. Living image was performed to assess the TRNNs distribution in vivo. The fluorescence intensity in the isolated brain of TRDNs-treated mice was about 8 times that of the DNs-treated. In the novel object recognition test, the mice after administration of TRDNs showed higher recognition index (0.414 ± 0.016) than the model group (0.275 ± 0.019). A significant increase in the number of dendritic spines from TRNNs administrated mice hippocampi neurons was observed after Golgi stain. This improvement of neurons was also confirmed by the significant high expression of PSD95 protein level in hippocampi. We measured the OD values of Aß25-35 induced PC12 cells that pre-treatment with different nanoparticles and concluded that TRNNs had a robust neuroprotection effect. Above all, functional biomimetic nanoparticles could increase the accumulation of naringenin into brain, thereby enable the drug to exert greater therapeutic effects.

Erythrocyte membrane-coated nanocarriers modified by TGN for Alzheimer's disease.

Alzheimer's disease (AD) is an aging-related neurodegenerative disease, and the main pathological feature was ß-amyloid protein (Aß) deposition. Recently, bioactive materials-based drug delivery system has been widely investigated for the treatment of AD. In this study, we developed a red blood cells (RBC) membrane-coated polycaprolactone (PCL) nanoparticles (NPs) loading with a therapeutic agent for AD, curcumin (Cur). A functional peptide TGNYKALHPHN (TGN) was conjugated to the surface of membrane for blood-brain barrier (BBB) transport (TGN-RBC-NPs-Cur). TGN peptide can be recognized by receptors on the BBB and has great potential for brain transport. To confirm the targeted delivery of Cur to the brain, a cell co-culturing immortalized human cerebral microvascular endothelial cells and human brain astrocytes glioblastoma (hCMEC/D3 and U-118MG) in vitro model was established. As a result, the BBB transporting ratio of TGN-RBC-NPs-FITC was 29.64% at 12 h which was approximately eight-fold than RBC-NPs-FITC. The improvement of drug accumulation in the AD lesion was confirmed by the NPs modified with the BBB-penetrating peptide in the fluorescence imaging and quantitative analysis with UPLC-MS/MS in vivo. The neuroprotective effects were evaluated with new object recognition behavioral test, in vitro AD cell model, dendritic spine stain, GFAP and IBA1 immunofluorescence stain. The spatial learning and memory abilities of the AD model mice treated with TGN-RBC-NPs-Cur were obviously enhanced compared with the AD control mice and were also better than Cur at the same dosage. These results were consistent with the values of protection index of rat adrenal pheochromocytoma cells (PC12 cells) treated by Aß25-35. TGN-RBC-NPs-Cur increased the dendritic segments densities and restrained activation of microglia and astrocytes of AD mice, as well as reversed cognitive function of AD mice. All of the results demonstrated TGN-RBC-NPs-Cur a promising therapeutic strategy for delaying the progression of AD by designing biomimetic nanosystems to deliver drugs into the brain.

Clinical application of spinal robot in cervical spine surgery: safety and accuracy of posterior pedicle screw placement in comparison with conventional freehand methods.

The novel robot-assisted (RA) technique has been utilized increasingly to improve the accuracy of cervical pedicle screw placement. Although the clinical application of the RA technique has been investigated in several case series and comparative studies, the superiority and safety of RA over conventional freehand (FH) methods remain controversial. Meanwhile, the intra-pedicular accuracy of the two methods has not been compared for patients with cervical traumatic conditions. This study aimed to compare the rate and risk factors of intra-pedicular accuracy of RA versus the conventional FH approach for posterior pedicle screw placement in cervical traumatic diseases. A total of 52 patients with cervical traumatic diseases who received cervical screw placement using RA (26 patients) and FH (26 patients) techniques were retrospectively included. The primary outcome was the intra-pedicular accuracy of cervical pedicle screw placement according to the Gertzbin-Robbins scale. Secondary outcome parameters included surgical time, intraoperative blood loss, postoperative drainage, postoperative hospital stay, and complications. Moreover, the risk factors that possibly affected intra-pedicular accuracy were assessed using univariate analyses. Out of 52 screws inserted using the RA method, 43 screws (82.7%) were classified as grade A, with the remaining 7 (13.5%) and 2 (3.8%) screws classified as grades B and C. In the FH cohort, 60.8% of the 79 screws were graded A, with the remaining screws graded B (21, 26.6%), C (8, 10.1%), and D (2, 2.5%). The RA technique showed a significantly higher rate of optimal intra-pedicular accuracy than the FH method (P = 0.008), but there was no significant difference between the two groups in terms of clinically acceptable accuracy (P = 0.161). Besides, the RA technique showed remarkably longer surgery time, less postoperative drainage, shorter postoperative hospital stay, and equivalent intraoperative blood loss and complications than the FH technique. Furthermore, the univariate analyses showed that severe obliquity of the lateral atlantoaxial joint in the coronal plane (P = 0.003) and shorter width of the lateral mass at the inferior margin of the posterior arch (P = 0.014) were risk factors related to the inaccuracy of C1 screw placement. The diagnosis of HRVA (P < 0.001), severe obliquity of the lateral atlantoaxial joint in the coronal plane (P < 0.001), short pedicle width (P < 0.001), and short pedicle height (P < 0.001) were risk factors related to the inaccuracy of C2 screw placement. RA cervical pedicle screw placement was associated with a higher rate of optimal intra-pedicular accuracy to the FH technique for patients with cervical traumatic conditions. The severe obliquity of the lateral atlantoaxial joint in the coronal plane independently contributed to high rates of the inaccuracy of C1 and C2 screw placements. RA pedicle screw placement is safe and useful for cervical traumatic surgery.

Cell Membrane Biomimetic Nanoparticles with Potential in Treatment of Alzheimer's Disease.

Alzheimer's disease (AD) is to blame for about 60% of dementia cases worldwide. The blood-brain barrier (BBB) prevents many medications for AD from having clinical therapeutic effects that can be used to treat the affected area. Many researchers have turned their attention to cell membrane biomimetic nanoparticles (NPs) to solve this situation. Among them, NPs can extend the half-life of drugs in the body as the "core" of the wrapped drug, and the cell membrane acts as the "shell" of the wrapped NPs to functionalize the NPs, which can further improve the delivery efficiency of nano-drug delivery systems. Researchers are learning that cell membrane biomimetic NPs can circumvent the BBB's restriction, prevent harm to the body's immune system, extend the period that NPs spend in circulation, and have good biocompatibility and cytotoxicity, which increases efficacy of drug release. This review summarized the detailed production process and features of core NPs and further introduced the extraction methods of cell membrane and fusion methods of cell membrane biomimetic NPs. In addition, the targeting peptides for modifying biomimetic NPs to target the BBB to demonstrate the broad prospects of cell membrane biomimetic NPs drug delivery systems were summarized.

Polylactic-co-glycolic acid-based nanoparticles modified with peptides and other linkers cross the blood-brain barrier for targeted drug delivery.

Because of the blood-brain barrier, only a limited fraction of drugs can penetrate the brain. As a result, there is a need to take larger doses of the drug, which may result in numerous undesirable side effects. Over the past few decades, a plethora of research has been conducted to address this issue. In recent years, the field of nanomedicine research has reported promising findings. Currently, numerous types of polylactic-co-glycolic acid-based drug-delivery systems are being studied, and great progress has been made in the modification of their surfaces with a variety of ligands. In this review, the authors highlight the preparation of polylactic-co-glycolic acid-based nanoparticles and single- and dual-targeted peptide modifications for site-specific drug delivery into the brain.

The blood­brain barrier prevents many drugs used to treat brain diseases from having clinical effects. To solve this issue, some promising findings have been reported in the field of nanomedicine research, which will be introduced in this article as possible effective methods for the treatment of brain diseases. This review will focus on the nature of the polylactic-co-glycolic acid polymers involved in the preparation of desired targeted nanocarriers, the synthesis methods for achieving the drug loaded system and the choice and preparation of the targeting agents.

C1 anatomy and dimensions relative to pedicle screw placement.

The recent C1 pedicle screw technique for upper cervical vertebral stabilization allows longer screws to be implanted by setting the screw entry point through the posterior arch of C1, which could provide better biomechanics. However, there is controversy regarding the placement of C1 pedicle screws at different angles. We retrospectively reviewed the computed tomography (CT) scans of 300 patients. The trajectories of medial inclination of 0°, 5°, 10°, and 15° and trajectory of the maximum medial inclination angle were designed for each C1 pedicle on CT images. Screw track length at each angle, the angle of maximum medial inclination, pedicle height, distance from the screw entry point to the midpoint of the C1 posterior tubercle, and screw perforation rate at each angle were measured. The average maximum inclination angle was 17.01°, the maximum inclination angle screw track length was 31.05 mm, and the distance from the screw entry point to the midpoint of the C1 posterior nodule was 21.65 mm. The screw perforation rate was 46.73% at 15° of medial inclination, but only 5.61% at 10°, and no screw perforation at 5°. 26.47% C1 pedicle height < 4 mm. There was no significant difference between the measured data on the left and right sides(P > 0.05), and the measurement of female patients was usually smaller and significantly different from that of male patients(p < 0.05). Our data indicate that a reasonable screw inclination angle of 10° and the safety zone of screw angle can provide safety and avoid screw perforation. However, personalized measurement before surgery is essential.

Robot-Assisted Percutaneous Lag Screw Osteosynthesis for C1 Lateral Mass Fractures: Case Series and Technical Note.

BACKGROUND: C1 lateral mass fractures (LMF) cause abnormal alignment of the upper cervical joints. Conservatively treated cases can develop into late cock-robin junction, requiring a reconstructive surgical procedure of the occipitocervical junction. Partial coronal C1 LMF could be effectively fixed with lag screws. Navigation and robot-assisted techniques have made percutaneous fixation possible and are gradually being used in the upper cervical spine. METHODS: Five consecutive patients with C1 LMF who underwent percutaneous lag screw osteosynthesis under the guidance of a new robotic system were reviewed retrospectively. Preoperative and postoperative computed tomography scans were used to specify the fracture types and to assess the efficacy of fracture reduction. The medical records were reviewed. RESULTS: Among the 5 patients, 4 underwent percutaneous lag screw reduction and fixation with the assistance of the robotic system through a posterior approach and 1 patient underwent a transoral approach. No intraoperative complications, such as screw malposition, neurologic deficit, and vertebral artery injury, occurred. Satisfactory fracture reduction and bone healing were achieved at postoperative follow-up. CONCLUSIONS: Robot-assisted percutaneous lag screw osteosynthesis is a viable option for C1 LMF. Different approaches can be selected according to the distribution of the fracture lines. With the posterior approach, the guidewire tends to deviate from the entry point because of skiving, and the technical problems need to be further solved. Screw implant by a transoral approach is comparatively easy to achieve, but the possibly of infection exists and should be monitored.

Posterior osteosynthesis with a new self-designed lateral mass screw-plate system for unstable atlas burst fractures.

BACKGROUND: In the treatment of unstable atlas fractures using the combined anterior-posterior approach or the posterior monoaxial screw-rod system, factors such as severe trauma or complex surgical procedures still need to be improved despite the favourable reduction effect. This research described and evaluated a new technique for the treatment of unstable atlas fracture using a self-designed lateral mass screw-plate system. METHODS: A total of 10 patients with unstable atlas fractures using this new screw-plate system from January 2019 to December 2021 were retrospectively reviewed. All patients underwent posterior open reduction and internal fixation (ORIF) with a self-designed screw-plate system. The medical records and radiographs before and after surgery were noted. Preoperative and postoperative CT scans were used to determine the type of fracture and evaluate the reduction of fracture. RESULTS: All 10 patients were successfully operated with this new system, with an average follow-up of 16.7 ± 9.6 months. A total of 10 plates were placed, and all 20 screws were inserted into the atlas lateral masses. The mean operating time was 108.7 ± 20.1 min and the average estimated blood loss was 98.0 ± 41.3 ml. The lateral mass displacement (LMD) averaged 7.1 ± 1.9 mm before surgery and almost achieved satisfactory reduction after surgery. All the fractures achieved bony healing without reduction loss or implant failure. No complications (vertebral artery injury, neurologic deficit, or wound infection) occurred in these 10 patients. At the final follow-up, the anterior atlantodens interval (AADI) was 2.3 ± 0.8 mm and the visual analog scale (VAS) was 0.6 ± 0.7 on average. All patients preserved almost full range of motion of the upper cervical spine and achieved a good clinical outcome at the last follow-up. CONCLUSIONS: Posterior osteosynthesis with this new screw-plate system can provide a new therapeutic strategy for unstable atlas fractures with simple and almost satisfactory reduction.

Symptoms and daily experiences reported by children with cancer using a game-based app.

PURPOSE: Mobile health (mHealth) resources, including apps, are emerging as resources to support children in tracking symptoms and other health-related data. The purpose of this study was to describe symptoms and daily experiences reported by elementary school-age children receiving treatment for cancer using the newly developed Color Me Healthy app. DESIGN AND METHODS: Participants in this descriptive study were children 6-12 years of age, who were receiving cancer treatment at a free-standing children's hospital in the Intermountain West of the United States. Children were requested to use the app for at least five days between clinical visits. Children's app-reported data were extracted from individual user accounts for analysis. Quantitative data were summarized descriptively. Qualitative data were summarized using qualitative content analysis. RESULTS: Nineteen children (6-12 years; median 8 years; 7 females) completed 107 days of app use. All children reported symptoms at least once, and 14 reported at least one day with a symptom of moderate or greater severity. Daily experiences reported through the app reflected children's engagement in usual childhood experiences while also describing life with cancer, including symptoms. CONCLUSIONS: Elementary school-age children are capable of self-reporting symptoms using a symptom reporting app, providing preliminary evidence for the potential benefits and clinical relevance of mHealth resources to support health outcomes within this population. PRACTICE IMPLICATIONS: Clinicians should anticipate and support ongoing symptom management needs between clinical visits. Children's self-reported data can promote a person-centered approach to symptom assessment and management.

Histopathologic Findings Associated With Matrix Metalloproteinases Proceeding to Recurrence of Primary Spontaneous Pneumothorax in Adolescents.

Background: Primary spontaneous pneumothorax is potentially life-threatening, and its recurrence is always a serious problem. Pathological examination provides molecular insights into the pathophysiology of primary spontaneous pneumothorax. Objectives: To investigate the association of histopathologic features of primary spontaneous pneumothorax with matrix metalloproteinase expression and their relevance to the recurrence. Methods: A total of 217 tissue section slides in 172 adolescent patients with primary spontaneous pneumothorax were retrospectively reviewed from January 2001 to June 2020. All histopathologic features were recorded and pathologic findings related to ipsilateral recurrence and second surgery were analyzed. Serum levels of matrix metalloproteinases were prospectively measured in 25 primary spontaneous pneumothorax patients receiving surgery and 18 healthy controls. Their relevance to the histopathologic features of primary spontaneous pneumothorax related to its recurrence was also examined. Results: The major presenting histopathologic findings of primary spontaneous pneumothorax were bleb/bulla (98%) followed by fibrosis (68%). Low prevalence of the pathologic findings of granulation tissue and macrophage accumulation were significantly associated with recurrent primary spontaneous pneumothorax, whereas fibrosis was significantly higher in patients receiving more than once surgery. Furthermore, the ratios of matrix metalloproteinase-2/tissue inhibitor of metalloproteinase-1 and matrix metalloproteinase-9/tissue inhibitor of metalloproteinase-1 were significantly higher in theses pathological findings as well as multinucleated giant cells and mesothelial cell hyperplasia in comparison with healthy controls. Conclusions: Low prevalence of macrophage accumulation and granulation tissue related to the overexpression of matrix metalloproteinase-2 and-9 activities may contribute to healing impairment and primary spontaneous pneumothorax recurrence.

Feasibility and acceptability of a game-based symptom-reporting app for children with cancer: perspectives of children and parents.

BACKGROUND: Children with cancer have difficulty identifying and describing the multiple symptoms they experience during hospitalization and between clinical encounters. Mobile health resources, including apps, are potential solutions to support child-centric symptom reporting. This study evaluated the feasibility and acceptability of a newly developed game-based symptom-reporting app for school-age children with cancer. PROCEDURE: Nineteen school-age children (6-12 years of age) receiving treatment for cancer at a COG institution in the Intermountain West of the United States used a game-based symptom-reporting app between clinical visits. Feasibility was evaluated through a summary of actual days of app use and interaction with each of the app's features. Children and their parents participated in interviews regarding the app's acceptability. RESULTS: Children used the app a median of 4 days (range 1-12) and interacted most frequently with the symptom reporting and the drawing features. Children enjoyed aspects of the app that supported their creativity and provided choices. Parents endorsed the interactive nature of the app and the value of the child providing his/her own report. Both children and parents identified additional opportunities to enhance the child's user experience. CONCLUSION: Study results support the preliminary feasibility and acceptability of the app. Children's and parents' responses supported the developmental relevance of the app and its role in enhancing the child's autonomy and serving as an outlet for creativity. Future directions include optimizing the child user's experience and investigating the app's role as a resource to enhance shared decision-making for symptom management.

Radial artery harvesting in coronary artery bypass grafting surgery-Endoscopic or open method? A meta-analysis.

We analyzed the clinical outcomes of open radial artery harvesting (OAH) and endoscopic radial artery harvesting (EAH) undergoing coronary artery bypass grafting (CABG). We designed this meta-analysis conducted using Pubmed, Medline, the Cochrane Library, and EMBASE. Articles with comparisons of OAH and EAH undergoing CABG were included. Primary outcomes included the wound infection rate, the wound complication rate, neurological complications of the forearm, in-hospital mortality, long-term survival, and the patency rate. The results of our study included six randomized controlled trials (RCTs), two non-randomized controlled trials (NRCTs) with matching, and 10 NRCTs. In total, 2919 patients were included in 18 studies, while 1187 (40.7%) and 1732 (59.3%) patients received EAH and OAH, respectively. EAH was associated with a lower incidence of wound infection (RR = 0.29, 95% confidence interval (CI) = 0.14 to 0.60, p = 0.03), and neurological complications over the harvesting site (RR = 0.41, 95% CI = 0.27 to 0.62, p < 0.0001). There was no significant difference in 30-day mortality, long-term survival (over one year), and the graft patency rate. According to our analysis, endoscopic radial artery harvesting can improve the outcome of the harvesting site, without affecting the mortality, long-term survival, and graft patency.

Site-directed MT1-MMP trafficking and surface insertion regulate AChR clustering and remodeling at developing NMJs.

At vertebrate neuromuscular junctions (NMJs), the synaptic basal lamina contains different extracellular matrix (ECM) proteins and synaptogenic factors that induce and maintain synaptic specializations. Here, we report that podosome-like structures (PLSs) induced by ubiquitous ECM proteins regulate the formation and remodeling of acetylcholine receptor (AChR) clusters via focal ECM degradation. Mechanistically, ECM degradation is mediated by PLS-directed trafficking and surface insertion of membrane-type 1 matrix metalloproteinase (MT1-MMP) to AChR clusters through microtubule-capturing mechanisms. Upon synaptic induction, MT1-MMP plays a crucial role in the recruitment of aneural AChR clusters for the assembly of postsynaptic specializations. Lastly, the structural defects of NMJs in embryonic MT1-MMP-/- mice further demonstrate the physiological role of MT1-MMP in normal NMJ development. Collectively, this study suggests that postsynaptic MT1-MMP serves as a molecular switch to synaptogenesis by modulating local ECM environment for the deposition of synaptogenic signals that regulate postsynaptic differentiation at developing NMJs.

Voluntary movement relies on skeletal muscle cells and nerve cells being able to communicate with one another. This communication occurs at a specialized region called the neuromuscular junction, or NMJ for short. These junctions are surrounded by a meshwork of proteins, known as the matrix, which structurally supports the nerve and muscle cells. Muscle cells contain proteins called acetylcholine receptors on their cell surface. When these receptors cluster together at the NMJ, this allows nerve cells to communicate with the muscle cell and tell the muscle to contract. However, these clusters can also form spontaneously without the help of nerve cells at regions away from the communication site. Alongside these spontaneous clusters of acetylcholine receptors are dynamic actin-enriched structures. These structures are responsible for releasing enzymes that digest the surrounding matrix and are commonly found in migrating cells. But as skeletal muscle cells do not migrate, it remained unclear what purpose these structures serve at the NMJ. Now, Chan et al. have used advanced microscopy techniques to show how these actin-enriched structures can help acetylcholine receptors cluster together at the site of communication between the nerve and muscle cells. The experiments showed that these structures direct a molecule called MT1-MMP to the muscle surface. This molecule then clears the surrounding matrix so that signals sent from the nerve can be effectively deposited at the narrow space between these two cells. When the muscle cells receive this initiating signal, acetylcholine receptors are recruited from the spontaneously formed clusters to the communication site, allowing the muscle to contract. When MT1-MMP was experimentally eliminated in mice, this disrupted the recruitment of acetylcholine receptors to the NMJ. Overall, these experiments help researchers understand how clearing the matrix between nerve and muscle cells contributes to the deposition of factors that build the communication site at developing NMJs. In the future this might help develop treatments for movement disorders caused by abnormalities that affect the clearing of matrix proteins in these junctions.

Priority Symptoms, Causes, and Self-Management Strategies Reported by AYAs With Cancer.

CONTEXT: Cancer and symptom experiences of adolescents and young adults (AYAs) with cancer can be highly variable, creating challenges for clinicians and researchers who seek to optimize AYAs' health outcomes. Understanding the heuristics AYAs use to designate priority symptoms can provide insight into the meaning they assign to their symptoms and self-management behaviors. OBJECTIVES: This study described the frequency and characteristics of priority symptoms. It qualitatively explored reasons for a symptom's designation as a priority symptom, perceived causes of priority symptoms, and strategies AYAs use to manage priority symptoms. METHODS: Participants in this single-group, longitudinal study reported symptoms using a heuristics-based symptom reporting tool, the Computerized Symptom Capture Tool, at two scheduled visits for chemotherapy. AYAs designated priority symptoms and responded to three short answer questions: What makes this a priority symptom?, What do you think causes it?, and What do you do to make it better? RESULTS: Eighty-six AYAs, 15-29 years of age (median 19 years), identified 189 priority symptoms. Priority symptoms were of greater severity (t = 3.43; P < 0.01) and distress (t = 4.02; P < 0.01) compared with nonpriority symptoms. Lack of energy, nausea, difficulty sleeping, and pain comprised 39% of priority symptoms. Reasons for priority designation included the impact of the symptom and the attributes of the symptom. Categories of self-management strategies included "Physical Care Strategies," "Things I take (or not)," and "Psychosocial Care Strategies." CONCLUSION: Supporting AYAs to identify their priority symptoms may facilitate a more personalized approach to care. Seeking the patient's perspective regarding priority symptoms could enhance patient-clinician collaboration in symptom management.

Using an incentive spirometer reduces pulmonary complications in patients with traumatic rib fractures: a randomized controlled trial.

BACKGROUND: An incentive spirometer (IS) is a mechanical device that promotes lung expansion. It is commonly used to prevent postoperative lung atelectasis and decrease pulmonary complications after cardiac, lung, or abdominal surgery. This study explored its effect on lung function and pulmonary complication rates in patients with rib fractures. METHODS: Between June 2014 and May 2017, 50 adult patients with traumatic rib fractures were prospectively investigated. Patients who were unconscious, had a history of chronic obstructive pulmonary disease or asthma, or an Injury Severity Score (ISS) ≥ 16 were excluded. Patients were randomly divided into a study group (n = 24), who underwent IS therapy, and a control group (n = 26). All patients received the same analgesic protocol. Chest X-rays and pulmonary function tests (PFTs) were performed on the 5th and 7th days after trauma. RESULTS: The groups were considered demographically homogeneous. The mean age was 55.2 years and 68% were male. Mean pretreatment ISSs and mean number of ribs fractured were not significantly different (8.23 vs. 8.08 and 4 vs. 4, respectively). Of 50 patients, 28 (56%) developed pulmonary complications, which were more prevalent in the control group (80.7% vs. 29.2%; p = 0.001). Altogether, 25 patients had delayed hemothorax, which was more prevalent in the control group (69.2% vs. 29.2%; p = 0.005). Two patients in the control group developed atelectasis, one patient developed pneumothorax, and five patients required thoracostomy. PFT results showed decreased forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1) in the control group. Comparing pre- and posttreatment FVC and FEV1, the study group had significantly greater improvements (p < 0.001). CONCLUSIONS: In conclusion, the use of an IS reduced pulmonary complications and improved PFT results in patients with rib fractures. The IS is a cost-effective device for patients with rib fractures and its use has clinical benefits without harmful effects. TRIAL REGISTRATION: ClinicalTrials.gov, NCT04006587. Registered on 3 July 2019.

Overexpression of matrix metalloproteinase-9 in adolescents with primary spontaneous pneumothorax for surgical intervention.

OBJECTIVE: To determine gene expression profiles associated with bullae formation in patients with primary spontaneous pneumothorax and to identify candidate genes associated with surgical intervention. METHODS: Twenty-four adolescents with primary spontaneous pneumothorax were enrolled prospectively. A global gene expression analysis of 9 paired lung biopsies (lesion and normal adjacent sites) was performed to identify differentially expressed genes associated with spontaneous pneumothorax. Pathway and network analysis was performed using the Database for Annotation, Visualization and Integrated Discovery web tool. Candidate genes and encoding proteins were assessed in blood samples and compared between patients with pneumothorax and healthy control patients. RESULTS: A total of 1519 differentially expressed transcripts corresponding to known genes were identified comparing the lesion lung with paired adjacent normal lung. The altered genes were mainly associated with focal adhesion and extracellular matrix-receptor interaction pathways. Genes involved in proteolysis and peptidase activity were up-regulated predominantly, especially matrix metalloproteinase-1 and -9 genes. Compared with the recovery stage, blood levels of matrix metalloproteinase-9/tissue inhibitor of metalloproteinase-1 were increased at the acute stage in patients with pneumothorax and, when compared between patients treated operatively with those treated nonoperatively, were also significantly greater. In addition, ratios of their serum levels were significantly greater in patients with pneumothorax compared with healthy control patients. Furthermore, matrix metalloproteinase-9 was predominantly overexpressed in neutrophils, alveolar macrophages, and mesothelial cells of lung biopsies. CONCLUSIONS: An imbalance of cell-extracellular matrix interactions appears to be associated with primary spontaneous pneumothorax. Matrix metalloproteinase-9 overexpression may particularly play a role in contributing to pleural porosity for surgical intervention.

Posterior osteosynthesis with monoaxial lateral mass screw-rod system for unstable C1 burst fractures.

BACKGROUND CONTEXT: Surgical treatment for unstable atlas fractures has evolved in recent decades from C1-C2 or C0-C2 fusion to motion-preservation techniques of open reduction and internal fixation (ORIF). However, regardless of a transoral or a posterior approach, the reduction is still not satisfactory. PURPOSE: The article describes and evaluates a new technique for treating unstable atlas fractures by using a monoaxial screw-rod system. STUDY DESIGN: This is a retrospective study. PATIENT SAMPLE: The sample includes adult patients with unstable C1 fractures treated with a posterior monoaxial screw-rod system. OUTCOME MEASURES: The outcome measures included a visual analog pain scale, radiographic reduction (lateral mass displacement [LMD]), maintenance of reduction, C1-C2 instability (anterior atlantodens interval), and complications. MATERIALS AND METHODS: From August 2013 to May 2016, nine consecutive patients with unstable atlas fractures were retrospectively reviewed. All patients were treated with posterior ORIF by using a monoaxial screw-rod system. The medical records and the preoperative and postoperative radiographs were reviewed. Preoperative and postoperative computed tomography scans were used to specify the fracture types and to assess the reduction. RESULTS: All nine patients with a mean age of 50.3 years successfully underwent surgery with this technique, and a follow-up of 17.4±9.3 months was performed. Transverse atlantal ligament (TAL) injury was found in eight of the nine patients: one of type I and seven of type II. The preoperative LMD averaged 7.0±2.2 mm and was restored completely after surgery; all the fractures achieved bony healing without loss of reduction or implant failure. None of the patients had complications of neurologic deficit, vertebral artery injury, or wound infection associated with the surgical procedure. Two patients complained of greater occipital nerve neuralgia after the operation, which gradually disappeared in 1 month. All patients had a well-preserved range of motion of the upper cervical spine at the final follow-up. CONCLUSIONS: Posterior osteosynthesis with a monoaxial screw-rod system is capable of an almost anatomical reduction for the unstable atlas fractures. The TAL incompetence may not be a contraindication to ORIF for C1 fractures, but the long-term effect of C1-C2 instability remains to be further investigated.