Does the Incorporation of Graphene Oxide into PMMA Influence its Antimicrobial Activity?

INTRODUCTION: The increase in infectious diseases mediated by oral bacteria has been one of the most potent threats to human health, specifically to the elderly. Researchers seek to incorporate antimicrobial nanomaterials into PMMA to control the colonization of microorganisms and reduce deadly diseases. OBJECTIVE: To conduct a systematic review to answer the question: "Does graphene oxide incorporated into polymethylmethacrylate influence its antimicrobial activity?" METHODS: The electronic search was performed in PubMed, Embase, Web of Science, Scopus, and Google Scholar databases, and articles published until October 2021 were selected. The search terms were: ("acrylic resin" OR PMMA) AND (graphene OR "oxide graphene") AND (antimicrobial OR antibacterial OR "anti-infective agent"). The risk of bias analysis of the articles was performed using the quasi-experimental study assessment tool adapted from the JBI. RESULTS: Two hundred and fifty-nine articles were found in the databases. After removing the duplicates, 245 were analyzed by title and abstract. Of these, 06 were selected for full reading, of which 03 met the eligibility criteria and were included in this systematic review. CONCLUSION: This systematic review's findings can infer that the incorporation of graphene in the form of graphene-based coatings to PMMA showed antimicrobial effectiveness.

Comparison Between Sagittal Balance Outcomes After Corpectomy, Laminectomy, and Fusion for Cervical Spondylotic Myelopathy: A Matched Cohort Study.

Cervical spondylotic myelopathy (CSM) can be successfully decompressed via either anterior cervical corpectomy and fusion (ACCF) or posterior laminectomy with fusion (LMF). However, few studies have compared the isolated effect of both techniques on cervical sagittal balance, a surrogate end point for clinical outcomes.We aimed to compare the sagittal balance radiological outcomes of ACCF against LMF. A case-matched controlled study of radiological cervical alignment parameters (C0-2, C2-3, index angles, T1 slope, and sagittal vertical axis (SVA)) in two groups of patients was performed by using pre- and postoperative neutral cervical X-rays.In total, 34 patients were enrolled (ACCF n = 17; LMF n = 17). The mean preoperative C2-7 angle was similar (11.58 ± 16.00° for ACCF; 13.36 ± 12.21° for LMF) in both cohorts. Both led to a loss of lordosis (-2.68 ± 13.8°, p = 0.43; -2.94 ± 11.5°, p = 0.31, respectively). At the C0-2, the two operations induced opposite variations (-0.9 ± 8.0°, p = 0.709 for ACCF; 3.5 ± 15.4°, p = 0.357 for LMF). ACCF led to a significant increase in SVA (7.1 ± 11.9 mm, p = 0.002). The C2-3 disk angle more pronouncedly increased with LMF.Both techniques show an equivalent kyphotic effect, with a greater disadvantage for ACCF. The negative impact on SVA changes is greater with ACCF. Both affect the C0-2 unit, with a tendency for kyphosis with ACCF and one for lordosis with LMF. When choosing the appropriate decompression and fusion technique, preoperative sagittal balance parameters should be included in the decision-making process.

Minimally Invasive Posterior Cervical Fusion: A Handsome Option.

Cervical spondylosis is the leading cause of cervical myelopathy. When surgery is indicated, it is commonly addressed through an anterior or posterior cervical approach, such as cervical discectomy and fusion (ACDF) or laminectomy and fusion (LMF). Besides their own merits, each one has specific approach- or device-related complications, such as dysphagia, significant postoperative pain, wound infection, adjacent segment degeneration (ASD), and pseudoarthrosis. Through a tissue-sparing minimally invasive technique, posterior cervical fusion (PCF) has shown unfolding compelling evidence of biomechanical stability, good clinical outcomes, and high fusion rates, with fewer complications and better econometrics. On the basis of our own experience, we discuss here the indications, advantages, and drawbacks of minimally invasive PCF.

Spinal Intradural Extramedullary Tumors: A Retrospective Analysis on Ten-Years' Experience of Minimally Invasive Surgery and a Comparison with the Open Approach.

Spinal intradural extramedullary (ID-EM) tumors are pathologies widely treated through a classical open approach. However, minimally invasive surgery is gaining traction as a comparable treatment option because it carries less morbidity and may reduce healthcare costs.This study aimed to compare the clinical and functional outcomes of open versus minimally invasive approaches for patients with ID-EM tumors. We performed a retrospective analysis on prospectively collected data from patients with ID-EM tumors submitted to surgery. Baseline features and operative variables were compared, including surgery duration and estimated blood loss (EBL). Postoperative data covered tumor histology, length of stay (LOS), complication(s), and neurological status (Medical Research Council (MRC) scale) at the last follow-up.In total, 46 patients were included: 30 (65.2%) operated through an open approach and 16 (34.8%) through a minimally invasive surgical (MIS) approach. The predominant histology type was schwannomas (43.5%). Lesions more frequently affected the lumbar spine (34.8%). The tumor dimensions were similar in both cohorts. The minimally invasive approach was on average 76.7 min faster and correlated positively with less EBL (140 mL less than that of the open approach). Patients in the MIS group had shorter LOSs (5.63 days vs. 17.27 days) and had fewer postoperative complications. No significant difference in functional outcome was found.MIS is as effective as the traditional approach in achieving comparable functional outcomes, with advantages such as shorter surgery durations, less blood loss, and shorter hospital LOSs.

Long-Term Clinical and Radiological Evaluation of Low-Grade Lumbar Spondylolisthesis Stabilization with Rigid Percutaneous Pedicle Screws.

The armamentarium of surgical treatment options for lumbar spondylolisthesis (LS) includes decompression alone, stabilization with interlaminar devices, or instrumented fusion, through open or minimally invasive approaches. Despite its safe profuse use in distinctive lumbar spine disorders, using percutaneous pedicle screws (PPSs) alone to stabilize LS has never been described before. We performed a retrospective study of prospectively collected data, enrolling 24 patients with LS and scrutinizing clinical and radiological outcomes. A statistically significant decrease in visual analog scale (VAS) scores (p < 0.001) and Oswestry Disability Index (ODI) scores (p < 0.001) was observed, as was a reduction in the intake of acetaminophen after surgery (p = 0.022). In the long-term, PPS effectively reduced the index-level range of motion (p < 0.001), reduced preoperative slippage (p = 0.03), and maintained foraminal height, thus accounting for the positive clinical outcomes. It induced a significant segmental kyphotic effect (p < 0.001) that was compensated for by a favorable increase in the pelvic incidence minus lumbar lordosis (PI-LL) index (0.028).

Development of nanostructured silver vanadates decorated with silver nanoparticles as a novel antibacterial agent.

In this work we report the synthesis, characterization and application of silver vanadate nanowires decorated with silver nanoparticles as a novel antibacterial agent. These hybrid materials were synthesized by a precipitation reaction of ammonium vanadate and silver nitrate followed by hydrothermal treatment. The silver vanadate nanowires have lengths of the order of microns and diameters around 60 nm. The silver nanoparticles decorating the nanowires present a diameter distribution varying from 1 to 20 nm. The influence of the pH of the reaction medium on the chemical structure and morphology of silver vanadates was studied and we found that synthesis performed at pH 5.5-6.0 led to silver vanadate nanowires with a higher morphological yield. The antimicrobial activity of these materials was evaluated against three strains of Staphylococcus aureus and very promising results were found. The minimum growth inhibiting concentration value against a MRSA strain was found to be ten folds lower than for the antibiotic oxacillin.

Influence of purified multiwalled carbon nanotubes on the mechanical and morphological behavior in poly (L-lactic acid) matrix.

Poly (L-latic acid) (PLLA) is a bioresorbable polymer widely used as a biomaterial, but its fragility can limit its use. An alternative is to produce polymer nanocomposites, which can enhance the mechanical properties of polymeric matrix, resulting in a material with differentiated properties. In this work, PLLA based nanocomposites containing 0.25, 0.5 and 1.0wt% of purified multiwalled carbon nanotubes (p-MWCNTs) were prepared by the solvent casting method. The morphology and mechanical properties results show an improvement in strain at break for 0.25 and 0.5wt% p-MWCNTs and an increase in stiffness and elastic modulus for all compositions. Nanocomposites presented a p-MWCNTs agglomeration; however, there was a good stress transfer between PLLA and p-MWCNTs, which was confirmed by the increase in the hardness and elastic modulus. Atomic force microscopy analysis indicated an increase in roughness after nanotube addition. The in vitro biological study showed that PLLA/p-MWCNTs nanocomposites are cytocompatible with osteoblasts cells. The capacity of PLLA nanocomposites to stimulate osteogenesis was investigated by alkaline phosphatase (ALP) activity assay. Higher ALP activity was found on osteoblasts cultured on nanocomposites with 0.25 and 0.5wt% p-MWCNT compared to neat PLLA, confirming that PLLA cytocompatibility was improved on these compositions. Finally, our results showed that by a simple and inexpensive solvent casting method, it is possible to manufacture biofunctional nanocomposites devices with potential for orthopedic applications.

Arterial hyperoxia in severe head injury: a useful or harmful option?

There is mounting evidence both from experimental and clinical studies that traumatic brain injury (TBI) is associated with a reduction of aerobic metabolism. This results from a variable combination of impaired substrate delivery and mitochondrial failure. Mitochondria, which are responsible for the production of 95% of cell adenosine triphosphate (ATP), may become compromised after TBI. On the other hand, in the very early period after the primary injury, oxygen delivery may be impaired due to arterial hypoxia and/or to a reduction of cerebral blood flow (CBF). As a consequence, 80-90% of patients who die of head injury show ischemia on histo-pathological examination of the brain tissue. In the absence of an appropriate treatment for TBI, these observations favored the hypothesis that manipulation of brain oxygen delivery could be a therapeutic tool to improve aerobic metabolism. Several strategies were developed, including the increase of cerebral perfusion pressure (CPP) using amines or the increase of arterial partial pressure of oxygen (PaO(2)) through hyperbaric oxygen (HBO) or normobaric hyperoxia. Several experimental and clinical studies, using normobaric hyperoxia, demonstrated an increase in brain tissue oxygen tension and a reduction of brain extracellular lactate levels, but there is no consensus about the biological meaning of these findings. For some authors, they translate an improvement of brain oxidative metabolism, while for others they represent only biological epiphenomena. The current review addresses the rational behind normobaric hyperoxia as a therapeutic application and discusses the experimental and clinical results achieved so far.

Cocaine-related acute subdural hematoma: an emergent cause of cerebrovascular accident.

A case of "spontaneous" acute subdural hematoma caused by cocaine abuse is described. As an isolated cerebrovascular event, related to cocaine abuse, this is the first report in the literature. It also represents a new differential diagnosis for nontraumatic acute subdural haematomas. The putative pathophysiology of the lesion is discussed.

"Basal durotomy" to prevent massive intra-operative traumatic brain swelling.

OBJECTIVE: Massive intraoperative swelling (IOS) is a potential complication of intracranial surgery for traumatic hematomas. We present a novel design of dural opening to minimize the risks of IOS. METHODS: Over the last eight years, we have used and evaluated a "reversed U-shaped" durotomy incision, which leaves the dura intact in the parasagittal region. Accordingly, the dura should be opened initially over the fronto-basal eminence of the frontal lobe anterior to the middle meningeal artery and sylvian region. The incision is then carried across the middle meningeal into the temporal region. Additional slit incisions may be made, as needed, around the circumference of the craniotomy in order to obtain sufficient access to remove a subdural hematoma. RESULTS: We have employed this technique in 220 trauma craniotomies without any case of uncontrolled IOS. In all patients a complete dural closure was obtained. CONCLUSION: When IOS is suspected, basal durotomy proved to be an excellent technique to prevent it, without compromising the total evacuation of the traumatic intracranial hematoma.

Structure characterization and mechanism of growth of PbTe nanocrystals embedded in a silicate glass.

A nanocomposite consisting of PbTe nanocrystals embedded in a silicate glass was studied by small-angle x-ray scattering during the early stage of isothermal annealing at 793 K. A theoretical function based on a model of spherical PbTe nanocrystals surrounded by a Pb and Te depleted shell fits well to all experimental curves. The time dependences of the nanocrystal radius and size of the depleted shell agree with the prediction of the theory of nucleation and growth by the classical mechanism of atomic diffusion.