Rapid, simple, and economical LC-MS/MS method for simultaneous determination of ceftazidime and avibactam in human plasma and its application in therapeutic drug monitoring.

WHAT IS KNOWN AND OBJECTIVE: Carbapenem-resistant Gram-negative bacterial pathogens continue to threaten public health. Avibactam (AVI), a novel non-ß-lactam ß-lactamase inhibitor, has been approved for use with ceftazidime (CAZ) mainly against carbapenem-resistant Enterobacteriaceae. Therapeutic drug monitoring (TDM) is urgently needed to optimize dosage regimens to maximize efficacy, minimize toxicity, and delay the emergence of resistance. This study aims to develop and validate a rapid, simple, and economical LC-MS/MS method for simultaneous determination of CAZ/AVI in human plasma. METHODS: Samples were processed by simple protein precipitation, and gradient elution strategy was applied to separate CAZ and AVI on a reverse-phase C18 column; with subsequent detection by the mass spectrometer in a positive and negative ion switching mode. Plasma samples from patients were analysed. RESULTS AND DISCUSSION: A 4-min run of LC-MS/MS was developed. The precision, trueness, matrix effect, extraction recovery, carry-over, dilution integrity, and stability were all acceptable for a bioanalytical method. The method was successfully applied to the determination of CAZ and AVI in patients, and a considerable PK variability of CAZ/AVI was observed among patients. WHAT IS NEW AND CONCLUSION: A robust, rapid, simple, and economical LC-MS/MS method for the simultaneous determination of CAZ and AVI was developed. The considerable PK variability of CAZ/AVI among patients demonstrates the clinical significance of TDM.

Does prophylactic vertebral augmentation reduce the refracture rate in osteoporotic vertebral fracture patients: a meta-analysis.

PURPOSE: In order to prevent the recurrent fracture after vertebral augmentation, the concept of prophylactic vertebral augmentation has been proposed, but its efficacy is still controversial. This study aimed to determine the efficacy of prophylactic vertebral augmentation for prevention of refracture in osteoporotic vertebral fracture patients. METHODS: Following PRISMA guidelines, a literature search was performed using PubMed, Embase and Web of Science databases for relevant studies published until February 2021. A meta-analysis of randomized controlled trials and retrospective controlled trials comparing prophylactic group versus nonprophylactic group was conducted. The primary outcome was the incidence of new vertebral compression fracture (VCF), and secondary outcomes were incidence of adjacent vertebral fracture (AVF) and remote vertebral fracture (RVF). RESULTS: A total of 6 studies encompassing 618 patients were included in the meta-analysis. The incidence of new VCF was reported in all six studies, and the result showed no significant difference between the two groups (OR: 0.509; 95% CI: 0.184-1.409). Four studies provided data on the incidence of AVF, and it was revealed that there was no significant difference between the two groups (OR: 0.689; 95% CI: 0.109-4.371). In view of the incidence of RVF, prophylactic group also did not differ significantly compared with nonprophylactic group (OR: 0.535; 95% CI: 0.167-1.709). CONCLUSIONS: The current evidence suggested that prophylactic vertebral augmentation might not be appropriate to diminish the risk of new VCF. Therefore, there is a need to investigate the mechanism of refracture and explore other preventive regimens to reduce the risk.

An injectable and photocurable methacrylate-silk fibroin/nano-hydroxyapatite hydrogel for bone regeneration through osteoimmunomodulation.

Tissue engineering has emerged as a promising approach for addressing bone defects. Most of the traditional 3D printing materials predominantly relying on polymers and ceramics. Although these materials exhibit superior osteogenic effects, their gradual degradation poses a limitation. Digital light processing (DLP) 3D bioprinting that uses natural biomaterials as bioinks has become one of the promising strategies for bone regeneration. In this study, we introduce a hydrogel biomaterial derived from silk fibroin (SF). Notably, we present the novel integration of nano-hydroxyapatite (nHA) into the hydrogel, forming a composite hydrogel that rapidly cross-links upon initiation. Moreover, we demonstrate the loading of nHA through non-covalent bonds in SilMA. In vitro experiments reveal that composite hydrogel scaffolds with 10 % nHA exhibit enhanced osteogenic effects. Transcriptomic analysis indicates that the composite hydrogel promotes bone regeneration by inducing M2 macrophage polarization. Furthermore, rat femoral defect experiments validate the efficacy of SilMA/nHA10 in bone regeneration. This study synthesis of a simple and effective composite hydrogel bioink for bone regeneration, presenting a novel strategy for the future implementation of digital 3D printing technology in bone tissue engineering.

Beyond Magnification and Illumination: Ergonomics with a 3D Exoscope in Lumbar Spine Microsurgery to Reduce Musculoskeletal Injuries.

OBJECTIVE: The risk of musculoskeletal injuries (MSIs) increases over years of practice which may lead to career-ending among surgeons. Exoscopes represent a new generation of imaging systems that help surgeons operate in a more comfortable posture. This article aimed to assess advantages and limitations, especially ergonomics with a 3D exoscope in lumbar spine microsurgery versus an operating microscope (OM) to reduce MSIs. METHODS: From March 2018 to May 2020, 90 patients with lumbar disc herniation undergoing a single-level minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) procedure were included. Forty-seven patients were operated with the assistance of the exoscope and 43 patients were operated with the assistance of the OM. Clinical data, magnification, and illumination were evaluated. In particular, the ergonomics of surgeons was evaluated by a questionnaire (subjective) and a rapid entire body assessment (REBA; objective). RESULTS: The postoperative outcomes were reasonably well balanced between the two groups. The handling of the exoscope was comparable to that of the OM. The depth perception, image quality, and illumination of the exoscope were inferior to those of the OM in MIS-TLIF with long and deep approaches. The educational and training function of the exoscope was superior to that of the OM. Importantly, surgeons rated the ergonomics of the exoscope as very high on the questionnaire and the REBA to the OM (P = 0.017). CONCLUSIONS: This study showed that the exoscope was a safe and effective alternative to the OM for assisting the MIS-TLIF procedure with the unique advantage of ergonomics to reduce musculoskeletal injuries.

Cervical and First Thoracic Spine Hounsfield Units Assessment and Relationship to Clinical Outcomes and Cervical Sagittal Parameters in Patients Undergoing Anterior Cervical Spine Surgery.

OBJECTIVE: This study had 3 objectives: to compare bone mineral density (BMD) from 3 axial slices, subchondral trabecular bone 2 mm inferior to the cranial endplate, middle of the vertebral body, and subchondral trabecular bone 2 mm superior to the caudal endplate; assess BMD variations and correlations of C1-T1 vertebrae; and correlate BMD with clinical outcomes and cervical sagittal parameters in patients undergoing anterior cervical discectomy and fusion. METHODS: The study enrolled 71 patients who underwent anterior cervical discectomy and fusion between March 2017 and January 2020. Patient demographics, clinical outcomes, cervical sagittal parameters, and Hounsfield units (HUs) of C1-T1 vertebrae were recorded. Analysis of variance was performed to compare HUs from the axial slices. Pearson correlation coefficient was performed to calculate the relationship between mean HUs of C1-T1 and to assess correlations of mean HUs with clinical outcomes and cervical sagittal parameters. RESULTS: There were no significant differences between HUs of 3 axial levels. Mean HUs were highest in the mid-cervical spine (C4). Significant correlations in mean HUs among all measured spinal levels were observed. Age, sex, and body mass index were not related to mean HUs. Visual analog scale, Neck Disability Index, and Patient Health Questionnaire-9 scores were not related to HUs before and after surgery. There were significant correlations among mean HUs of C2-T1 vertebrae, C2-C7 sagittal vertical axis, and cranial tilt. Mean HUs of C4 had the strongest correlation with C2-C7 sagittal vertical axis. CONCLUSIONS: To our knowledge, this is the first study of cranial and caudal subchondral trabecular BMD using HUs and comparing them with the middle of the vertebral body and study of correlations between mean HUs of C1-T1 vertebrae and clinical outcomes and cervical sagittal parameters. Correcting C2-C7 sagittal vertical axis and cranial tilt would improve BMD of C1-T1 vertebrae.

Cervical Spine Microsurgery with the High-Definition 3D Exoscope: Advantages and Disadvantages.

OBJECTIVE: The aim of this study was to evaluate our experience with a high-definition 3-dimensional (3D) exoscope (EX) for cervical spine surgery versus a binocular operating microscope (OM). METHODS: A retrospective review of patients undergoing a single-level anterior cervical discectomy and fusion (ACDF) procedure for the treatment of cervical myelopathy from March 2019 to May 2020 was performed. Demographic, perioperative, and clinical outcomes of 50 patients were included, 23 of whom received assistance from the 3D exoscope (EX group) and 27 of whom received assistance from the OM (OM group). Operative baseline and postoperative outcome parameters were evaluated. Periprocedural handling, visualization, and illumination by the EX, as well as surgeons' ergonomics, were scored using a questionnaire and rapid upper limb assessment (RULA). RESULTS: Baseline characteristics were similar between the 2 groups. There were no significant differences between groups in mean operative time, blood loss, duration of admission, or postoperative improvement of symptoms. Both groups showed similar clinical improvements after surgery. There were no intraoperative complications in either group. According to the attending surgeons, the intraoperative handling of instruments for the EX was rated to be comparable to that of the OM. Surgeons rated the comfort level of the intraoperative posture for the EX as very high on the subjective questionnaire and equal to the OM on the objective RULA. When compared with the OM, depth perception, image quality, and illumination for the EX were rated as inferior in ACDF procedures with long approaches. The operative education and training function of the EX was rated to be superior to that of the OM. CONCLUSIONS: Overall, our study showed that the EX appears to be a safe alternative for common ACDF with the unique advantage of excellent comfort and also serves a useful educational tool for the surgical team. However, our investigation revealed several important limitations of this system, including slightly inferior visualization and illumination quality compared with the OM.

Preparation of band gap tunable SnO2 nanotubes and their ethanol sensing properties.

SnO(2) nanotubes have been prepared via a facile hydrothermal method at low temperatures using polycarbonate (PC) membrane as a hard template. The walls of as-prepared SnO(2) nanotubes are composed of fine nanocrysalline particles and the size of SnO(2) nanocrystals could be modified by changing reaction temperature. Formation mechanism of SnO(2) nanotubes is also discussed according to the experimental results. Cathodoluminescence properties of the SnO(2) product indicated that the band gap of the nanostructures increase from 3.75 eV with a particle size 5.6 nm to 3.99 eV with a particle size 3.3 nm. The as-prepared SnO(2) nanotubes were found to show enhanced gas-sensing activity and may be used as a candidate for the fabrication of gas sensors.

Facile fabrication and optical property of hollow SnO2 spheres and their application in water treatment.

Hollow SnO(2) spheres with smooth surface have been fabricated by a low temperature template-free solution phase route via self-assembly of small nanocrystalline particles. These hollow spheres have a very thin shell thickness of about 10 nm and are built from SnO(2) nanocrystals of an average size of 5.3 nm. The evacuation behavior of inside-out Ostwald ripening can be used to explain the formation of hollow spheres according to results of time-dependent reactions. The cathodoluminescence spectrum indicates a blue shift of the band gap emission peak of SnO(2), originating from quantum confinement effect due to the nanoscale size of SnO(2) particles. The as-prepared SnO(2) hollow spheres were also found to exhibit excellent performance in wastewater treatment.

Controlled Growth of Carbon Spheres Through the Mg-Reduction Route.

Hollow spheres, hollow capsules and solid spheres of carbon were selectively synthesized by Mg-reduction of hexachlorobutadiene at appropriate reaction conditions. X-ray powder diffraction and Raman spectra reveal that the as-prepared materials have a well-ordered structure. A possible formation mechanism has been proposed.