Rethinking Oncologic Facial Nerve Reconstruction in the Acute Phase Through Classification of the Level of Injury.

Early facial nerve reconstruction should be offered in every patient with oncological resections of the facial nerve due to the debilitating functional and psychosocial consequences of facial nerve palsy. Oncologic pathology or oncologic resection accounts for the second most common cause of facial nerve palsy. In the case of these acute injuries, selecting an adequate method for reconstruction to optimize functional and psychosocial well-being is paramount. Authors advocate consideration of the level of injury as a framework for approaching the viable options of reconstruction systematically. Authors break down oncologic injuries to the facial nerve in three levels in relation to their nerve reconstruction methods and strategies: Level I (intracranial to intratemporal), Level II (intratemporal to extratemporal and intraparotid), and Level III (extratemporal and extraparotid). Clinical features, common clinical scenarios, donor nerves available, recipient nerve, and reconstruction priorities will be present at each level. Additionally, examples of clinical cases will be shared to illustrate the utility of framing acute facial nerve injuries within injury levels. Selecting donor nerves is critical in successful facial nerve reconstruction in oncological patients. Usually, a combination of facial and non-facial donor nerves (Hybrid) is necessary to achieve maximal reinnervation of the mimetic muscles. Our proposed classification of three levels of facial nerve injuries provides a selection guide, which prioritizes methods for function nerve reconstruction in relation of the injury level in oncologic patients while prioritizing functional outcomes.

Structural interactions in polymer-stabilized magnetic nanocomposites.

Superparamagnetic iron oxide nanoparticles (SPIONs) have attracted significant attention because of their nanoscale magnetic properties. SPION aggregates may afford emergent properties, resulting from dipole-dipole interactions between neighbors. Such aggregates can display internal order, with high packing fractions (>20%), and can be stabilized with block co-polymers (BCPs), permitting design of tunable composites for potential nanomedicine, data storage, and electronic sensing applications. Despite the routine use of magnetic fields for aggregate actuation, the impact of those fields on polymer structure, SPION ordering, and magnetic properties is not fully understood. Here, we report that external magnetic fields can induce ordering in SPION aggregates that affect their structure, inter-SPION distance, magnetic properties, and composite Tg. SPION aggregates were synthesized in the presence or absence of magnetic fields or exposed to magnetic fields post-synthesis. They were characterized using transmission electron microscopy (TEM), small angle X-ray scattering (SAXS), superconducting quantum interference device (SQUID) analysis, and differential scanning calorimetry (DSC). SPION aggregate properties depended on the timing of field application. Magnetic field application during synthesis encouraged preservation of SPION chain aggregates stabilized by polymer coatings even after removal of the field, whereas post synthesis application triggered subtle internal reordering, as indicated by increased blocking temperature (TB), that was not observed via SAXS or TEM. These results suggest that magnetic fields are a simple, yet powerful tool to tailor the structure, ordering, and magnetic properties of polymer-stabilized SPION nanocomposites.

Localized Plasmonic Heating for Single-Molecule DNA Rupture Measurements in Optical Tweezers.

To date, studies on the thermodynamic and kinetic processes that underlie biological function and nanomachine actuation in biological- and biology-inspired molecular constructs have primarily focused on photothermal heating of ensemble systems, highlighting the need for probes that are localized within the molecular construct and capable of resolving single-molecule response. Here we present an experimental demonstration of wavelength-selective, localized heating at the single-molecule level using the surface plasmon resonance of a 15 nm gold nanoparticle (AuNP). Our approach is compatible with force-spectroscopy measurements and can be applied to studies of the single-molecule thermodynamic properties of DNA origami nanomachines as well as biomolecular complexes. We further demonstrate wavelength selectivity and establish the temperature dependence of the reaction coordinate for base-pair disruption in the shear-rupture geometry, demonstrating the utility and flexibility of this approach for both fundamental studies of local (nanometer-scale) temperature gradients and rapid and multiplexed nanomachine actuation.

Cooperative control of a DNA origami force sensor.

Biomolecular systems are dependent on a complex interplay of forces. Modern force spectroscopy techniques provide means of interrogating these forces, but they are not optimized for studies in constrained environments as they require attachment to micron-scale probes such as beads or cantilevers. Nanomechanical devices are a promising alternative, but this requires versatile designs that can be tuned to respond to a wide range of forces. We investigate the properties of a nanoscale force sensitive DNA origami device which is highly customizable in geometry, functionalization, and mechanical properties. The device, referred to as the NanoDyn, has a binary (open or closed) response to an applied force by undergoing a reversible structural transition. The transition force is tuned with minor alterations of 1 to 3 DNA oligonucleotides and spans tens of picoNewtons (pN). The DNA oligonucleotide design parameters also strongly influence the efficiency of resetting the initial state, with higher stability devices (≳10 pN) resetting more reliably during repeated force-loading cycles. Finally, we show the opening force is tunable in real time by adding a single DNA oligonucleotide. These results establish the potential of the NanoDyn as a versatile force sensor and provide fundamental insights into how design parameters modulate mechanical and dynamic properties.

Pain Medication Prescribing Patterns in Augmentation Mammoplasty.

Background: The rate of opioid prescribing after low-risk surgical procedures has increased over the past decade, and surgeons are responsible for prescribing approximately one-third of all opioid medications. There is additional supporting evidence that patients only consume about half of the opioids prescribed to them after outpatient plastic surgery. Currently, there is no literature to provide surgeons with reference ranges for how much opioid medication will adequately provide analgesia for patients after undergoing bilateral breast augmentation (BBA) surgery. Objective: To quantify the amount of opioid medication required to adequately control pain for patients after undergoing BBA and use these data to provide recommendations on opioid prescribing practices. Methods: Cross-sectional prospective data were obtained through a take-home medication and pain tracking questionnaire for 56 patients after they underwent either subpectoral or subglandular BBA. Patients documented their pain scores on a 0 to 10 analogue scale and documented the type and amount of pain medication they took for a 7-day period. Results: Our study demonstrated that patients in the subglandular BBA group required an average of either 25 ± 1.2 Tylenol #3 or 19.3 ± 2.3 Tramacet tablets, and the subpectoral group required 27.7 ± 1.7 Tylenol #3 or 25.6 ± 0.9 Tramacet tablets over a 7-day period. There was no statistically significant difference between the 2 surgical groups. Conclusion: We propose a reference range of medication required on average for patients undergoing BBA to obtain adequate pain control in the initial postoperative period that falls within the most recent Canadian guidelines for safe opioid prescribing practices.

Contexte: La fréquence de prescription des opioïdes après des procédures chirurgicales à faible risque a augmenté au cours de la dernière décennie et les chirurgiens sont responsables de la prescription d'environ un tiers de tous les médicaments opioïdes. Des données probantes supplémentaires indiquent que les patients ne consomment qu'environ la moitié des opioïdes qui leur ont été prescrits après une chirurgie plastique en chirurgie de jour. Aucune publication ne procure, à ce jour, des plages de référence aux chirurgiens pour leur indiquer combien d'opioïdes fournira aux patients une analgésie adéquate après avoir subi une chirurgie bilatérale d'augmentation mammaire. Objectif: Quantifier les médicaments opioïdes requis pour contrôler efficacement la douleur chez les patients ayant subi une chirurgie bilatérale d'augmentation mammaire et utiliser ces données pour fournir des recommandations sur les pratiques de prescription des opioïdes. Méthodes: Des données prospectives transversales ont été obtenues au moyen d'un questionnaire à remplir à domicile de suivi des médicaments et de la douleur auprès de 56 patientes venant de subir une chirurgie d'augmentation mammaire sous-pectorale ou sous-glandulaire. Les patientes ont documenté leurs scores de douleur sur une échelle analogique de 0 à 10, ainsi que le type et la quantité de médicament antidouleurs pris pendant une période de 7 jours. Résultats: Notre étude a démontré que les patientes du groupe augmentation mammaire sous glandulaire a nécessité une moyenne de 25 ± 1,2 comprimés de Tylénol #3 ou 19,3 ± 2,3 comprimés de Tramacet; les patientes du groupe sous-pectoral ont nécessité 27,7 ± 1,7 comprimés de Tylénol #3 ou 25,6 ± 0,9 comprimés de Tramacet comprimés sur une période de sept jours. Il n'y a pas eu de différence statistiquement significative entre les deux groupes chirurgicaux. Conclusion: Nous proposons une plage de référence pour les médicaments nécessaires en moyenne pour les patientes subissant une chirurgie d'augmentation mammaire pour contrôler correctement la douleur au cours de la période postopératoire initiale; cette plage de référence correspond aux plus récentes lignes directrices canadiennes sur les pratiques de prescription sécuritaire des opioïdes.

Cooperative control of a DNA origami force sensor.

Most biomolecular systems are dependent on a complex interplay of forces. Modern force spectroscopy techniques provide means of interrogating these forces. These techniques, however, are not optimized for studies in constrained or crowded environments as they typically require micron-scale beads in the case of magnetic or optical tweezers, or direct attachment to a cantilever in the case of atomic force microscopy. We implement a nanoscale force-sensing device using a DNA origami which is highly customizable in geometry, functionalization, and mechanical properties. The device, referred to as the NanoDyn, functions as a binary (open or closed) force sensor that undergoes a structural transition under an external force. The transition force is tuned with minor alterations of 1 to 3 DNA oligonucleotides and spans tens of picoNewtons (pN). This actuation of the NanoDyn is reversible and the design parameters strongly influence the efficiency of resetting the initial state, with higher stability devices (≳10 pN) resetting more reliably during repeated force-loading cycles. Finally, we show that the opening force can be adjusted in real time by the addition of a single DNA oligonucleotide. These results establish the NanoDyn as a versatile force sensor and provide fundamental insights into how design parameters modulate mechanical and dynamic properties.

Evaluating glioblastoma tumour sphere growth and migration in interaction with astrocytes using 3D collagen-hyaluronic acid hydrogels.

Glioblastoma (GB) is an astrocytic brain tumour with a low survival rate, partly because of its highly invasive nature. The GB tumour microenvironment (TME) includes its extracellular matrix (ECM), a variety of brain cell types, unique anatomical structures, and local mechanical cues. As such, researchers have attempted to create biomaterials and culture models that mimic features of TME complexity. Hydrogel materials have been particularly popular because they enable 3D cell culture and mimic TME mechanical properites and chemical composition. Here, we used a 3D collagen I-hyaluronic acid hydrogel material to explore interactions between GB cells and astrocytes, the normal cell type from which GB likely derives. We demonstrate three different spheroid culture configurations, including GB multi-spheres (i.e., GB and astrocyte cells in spheroid co-culture), GB-only mono-spheres cultured with astrocyte-conditioned media, and GB-only mono-spheres cultured with dispersed live or fixed astrocytes. Using U87 and LN229 GB cell lines and primary human astrocytes, we investigated material and experiment variability. We then used time-lapse fluorescence microscopy to measure invasive potential by characterizing the sphere size, migration capacity, and weight-averaged migration distance in these hydrogels. Finally, we developed methods to extract RNA for gene expression analysis from cells cultured in hydrogels. U87 and LN229 cells displayed different migration behaviors. U87 migration occurred primarily as single cells and was reduced with higher numbers of astrocytes in both multi-sphere and mono-sphere plus dispersed astrocyte cultures. In contrast, LN229 migration exhibited features of collective migration and was increased in monosphere plus dispersed astrocyte cultures. Gene expression studies indicated that the most differentially expressed genes in these co-cultures were CA9, HLA-DQA1, TMPRSS2, FPR1, OAS2, and KLRD1. Most differentially expressed genes were related to immune response, inflammation, and cytokine signalling, with greater influence on U87 than LN229. These data show that 3D in vitro hydrogel co-culture models can be used to reveal cell line specific differences in migration and to study differential GB-astrocyte crosstalk.

DNA-caged nanoparticles via electrostatic self-assembly.

DNA-modified nanoparticles enable DNA sensing and therapeutics in nanomedicine and are also crucial for nanoparticle self-assembly with DNA-based materials. However, methods to conjugate DNA to nanoparticle surfaces are limited, inefficient, and lack control. Inspired by DNA tile nanotechnology, we demonstrate a new approach to nanoparticle modification based on electrostatic attraction between negatively charged DNA tiles and positively charged nanoparticles. This approach does not disrupt nanoparticle surfaces and leverages the programmability of DNA nanotechnology to control DNA presentation. We demonstrated this approach using a vareity of nanoparticles, including polymeric micelles, polystyrene beads, gold nanoparticles, and superparamagnetic iron oxide nanoparticles with sizes ranging from 5-20 nm in diameter. DNA cage formation was confirmed through transmission electron microscopy (TEM), neutralization of zeta potential, and a series of fluorescence experiments. DNA cages present "handle" sequences that can be used for reversible target attachment or self-assembly. Handle functionality was verified in solution, at the solid-liquid interface, and inside fixed cells, corresponding to applications in biosensing, DNA microarrays, and erasable immunocytochemistry. These experiments demonstrate the versatility of the electrostatic DNA caging approach and provide a new pathway to nanoparticle modification with DNA that will empower further applications of these materials in medicine and materials science.

Malignant Peripheral Nerve Sheath Tumors of the Brachial Plexus: A Single-Center Experience on Diagnosis, Management, and Outcomes.

INTRODUCTION: The incidence of malignant peripheral nerve sheath tumors (MPNSTs) is 0.001%. Commonly, MPNST arise in neurofibromatosis; however, they can occur sporadically, de novo or from a preexisting neurofibroma. Malignant peripheral nerve sheath tumors are aggressive tumors with high rates of local recurrence and metastasis. The prognosis is poor with 5-year survival rates of 15% to 50%. Unfortunately, given the rarity of these tumors, it is not clear how to best manage these patients. The purposes of this study were (1) to discuss our experience with MPNST and particularly our difficulties with diagnosis and management, and (2) to review the literature. MATERIALS AND METHODS: We report on all tumors of the brachial plexus excised between 2013 and 2019. We report 3 cases of MPNST, their treatment, and their outcomes. RESULTS: Thirteen patients underwent surgical excision of an intrinsic brachial plexus mass. Three of these patients (2 male, 1 female; average age, 36 years) were diagnosed with an MPNST. Two patients with an MPNST had neurofibromatosis type 1. All patients with an MPNST had a tumor >8 cm, motor and sensory deficits, and pain. All 3 patients with MPNST underwent a magnetic resonance imaging (MRI) before diagnosis. The average time from initial symptom onset to MRI was 12.3 months. Only 1 of the MRIs suggested a malignant tumor, with no MRI identifying an MPNST. One patient underwent an excisional biopsy, and 2 had incisional biopsies. Because of the lack of diagnosis preoperatively, all patients had positive margins given the limited extent of surgery. Returning for excision in an attempt to achieve negative margins in a large oncologically contaminated field was not possible because defining the boundaries of the initial surgical field was unachievable; therefore, the initial surgery was their definitive surgical management. All patients were referred to oncology and received radiation therapy. CONCLUSIONS: Malignant peripheral nerve sheath tumors must be suspected in enlarging masses (>5 cm) with the constellation of pain, motor, and sensory deficits. Computed tomography- or ultrasound-guided core needle biopsy under brachial plexus block or sedation is required for definitive diagnosis to allow for a comprehensive approach to the patient's tumor with a higher likelihood of disease-free survival.

Systemic thrombolytic and ultrasound-assisted catheter-directed thrombolysis for treatment of acute pulmonary embolism: a 7-year, multicenter experience.

Treatment of acute pulmonary embolism (PE) varies based upon risk stratification and ranges from outpatient oral anticoagulation to emergency surgical embolectomy. Patients with high-risk PE can be considered for systemic thrombolytic (ST) based upon guideline recommendations, but intermediate-risk PE does not currently have strong evidence to guide primary reperfusion strategies via thrombolytic administration. Ultrasound-assisted catheter-directed thrombolysis (USAT) is an alternative reperfusion option to ST but is not currently recommended as first line in any key guidelines due to limited available evidence. This retrospective, multicenter, observational study compares 210 patients treated with USAT (n = 105) or ST (n = 105) for acute high- or intermediate-risk PE in three hospitals. Baseline characteristics were significant in that severity of illness was higher in those that received ST, which limited comparisons of outcomes. The primary outcome of major bleeding in patients receiving USAT was 15.2% and 22.9% in those that received ST. Efficacy of reperfusion strategy was observed to be 86.7% of patients in USAT group and 65.7% in ST group. Reperfusion strategies had no difference in in-hospital death, intensive care length of stay, or hospital length of stay. Predefined subgroup analysis found that high-risk PE had higher mortality (14.7%) than intermediate-risk PE (0%) regardless of reperfusion strategy. Upon multivariate analysis, high-risk PE was the only independent risk factor for major bleeding while USAT therapy and intermediate-risk PE were independent predictors of efficacy. Due to the difference in baseline severity of illness, direct comparisons in primary outcomes to each group was not performed. We have described real world usage of both USAT and ST and which patients were likely to receive each therapy at these institutions.

Major Publications in the Critical Care Pharmacotherapy Literature: 2021.

To summarize the most impactful articles relevant to the pharmacotherapy of critically ill adult patients published in 2021. DATA SOURCE: PubMed/MEDLINE. STUDY SELECTION: Randomized controlled trials, prospective studies, or systematic review/meta-analyses of adult critical care patients assessing a pharmacotherapeutic intervention and reporting clinical endpoints published between January 1, 2021, and December 31, 2021. DATA EXTRACTION: Candidate articles were organized by clinical domain based on the emerging themes from all studies. A modified Delphi process was applied to obtain consensus on the most impactful publication within each clinical domain based on overall contribution to scientific knowledge and novelty to the literature. DATA SYNTHESIS: The search revealed 830 articles, of which 766 were excluded leaving 64 candidate articles for the Delphi process. These 64 articles were organized by clinical domain including: emergency/neurology, cardiopulmonary, nephrology/fluids, infectious diseases, metabolic, immunomodulation, and nutrition/gastroenterology. Each domain required the a priori defined three Delphi rounds. The resultant most impactful articles from each domain included five randomized controlled trials and two systematic review/meta-analyses. Topics studied included sedation during mechanical ventilation, anticoagulation in COVID-19, extended infusion beta-lactams, interleukin-6 antagonists in COVID-19, balanced crystalloid resuscitation, vitamin C/thiamine/hydrocortisone in sepsis, and promotility agents during enteral feeding. CONCLUSIONS: This synoptic review provides a summary and perspective of the most impactful articles relevant to the pharmacotherapy of critically ill adults published in 2021.

Reversal of apixaban and rivaroxaban with andexanet alfa prior to invasive or surgical procedures.

BACKGROUND: Outcomes following andexanet alfa reversal of factor Xa inhibitors in patients requiring urgent or emergent invasive procedures are lacking. This study aimed to describe efficacy and safety outcomes following andexanet alfa administration within 24 h of an invasive procedure. METHODS: This single-center, observational, retrospective study included patients who received andexanet alfa within 24 h of an invasive or surgical procedure. The primary outcome was hemostatic efficacy graded as excellent, good, or poor using similar definitions to the ANNEXA-4 criteria. Secondary outcomes included hospital discharge disposition, intensive care unit (ICU) and hospital length of stay, 30-day mortality, 30-day thromboischemic event rates, and serum coagulation assay changes pre- and postreversal. RESULTS: Forty-four patients met inclusion criteria; of these, 27 (62.8%) received apixaban and 16 (37.2%) were treated with rivaroxaban prior to admission. The indications for reversal were categorized as intracranial (n = 20 [45.5%]) or extracranial (n = 24 [54.5%]) sites. Majority of patients required emergent operative procedures (18 [40.9%]), followed by invasive device placement (10 [22.7%]) or arterial embolization (9 [20.5%]). Thirty-eight (86.4%) patients were able to be adequately graded for hemostatic efficacy. Overall, 30 (78.9%) patients achieved excellent or good hemostasis within 24 h after periprocedural administration of andexanet alfa (19 [82.6%] apixaban vs. 11 [78.6%] rivaroxaban; 12 [80.0%] intracranial events vs. 18 [78.3%] extracranial events). Discharge disposition was most often to a short- or long-term care facilities (27 [61.4%]). Thirty-day mortality and thromboischemic complications occurred in 15 (34.1%) and 12 (27.3%) patients, respectively. Prothrombin time and antifactor Xa assay results were significantly decreased after andexanet alfa administration (p < 0.05) while thromboelastogram assay values (reaction time, kinetic time, and activated clotting time) showed nonsignificant changes pre- versus postreversal. CONCLUSION: Andexanet alfa may be used for urgent or emergent reversal of apixaban and rivaroxaban peri-procedurally with promising hemostatic outcomes. Further prospective, comparative clinical research is warranted.

Surgical Treatment of Parsonage Turner Syndrome With Primary Nerve Transfers: A Case Series and Cadaver Dissection.

ABSTRACT: Parsonage Turner syndrome (PTS) is the development of severe, spontaneous pain with subsequent nerve palsy. Unfortunately, many patients never achieve full functional recovery, and many have chronic pain. The use of nerve transfers in PTS has not been reported in the literature. We present 4 cases of PTS treated surgically with primary nerve transfer and neurolysis of the affected nerve following the absence of clinical and electrodiagnostic recovery at 5 months from onset. In addition, we present a cadaver dissection demonstrating an interfascicular dissection of the anterior interosseous nerve (AIN) into its components to enable a fascicular transfer in partial AIN neuropathy. Two patients with complete axillary neuropathy underwent a neurorrhaphy between the nerve branch to the lateral head of the triceps and the anterior/middle deltoid nerve branch of the axillary nerve. Two patients with partial AIN neuropathy involving the FDP to the index finger (FDP2) underwent a neurorrhaphy between an extensor carpi radialis brevis nerve branch and the FDP2 nerve branch. All patients had neurolysis of the affected nerves. All subjects recovered at least M4 motor strength. The cadaver dissection demonstrates 3 separate nerve fascicles of the AIN into FPL, FDP2, and pronator quadratus that can be individually selected for reinnervation with a fascicular nerve transfer. Functional recovery for patients with PTS with neurolysis alone is variable. Surgical treatment with neurolysis and a nerve transfer to improve functional recovery when no recovery is seen by 5 months is an option.

Oxidation of quantum dots encapsulated in block copolymer micelles as a function of polymer terminal charge.

Most high-quality quantum dots (QDs) are synthesized in the organic phase, and are often coated with polymers for use in aqueous biological environments. QDs can exhibit fluorescence losses during phase transfer, but evaluating underlying mechanisms (e.g., oxidation, surface etching, loss of colloidal stability) can be challenging because of variation in synthesis methods. Here, fluorescence stability of QDs encapsulated in block co-polymer (BCP) micelles was investigated as a function of BCP terminal functionalization (i.e., -OH, -COOH, and -NH2 groups) and synthesis method (i.e., electrohydrodynamic emulsification-mediated selfassembly (EE-SA), sonication, and manual shaking). Fluorescence losses, fluorescence intensity, energy spectra, and surface composition were assessed using spectrofluorometry and cathodoluminescence spectroscopy (CL) with integrated X-ray photoemission spectroscopy (XPS). QDs passivated using charged BCPs exhibited 50-80% lower fluorescence intensity than those displaying neutral groups (e.g., -OH), which CL/XPS revealed to result from oxidation of surface Cd to CdO. Fluorescence losses were higher for processes with slow formation speed, but minimized in the presence of poly(vinyl alcohol) (PVA) surfactant. These data suggest slower BCP aggregation kinetics rather than electrostatic chain repulsion facilitated QD oxidation. Thus, polymer coating method and BCP structure influence QD oxidation during phase transfer and should be selected to maximize fast aggregation kinetics.

One step closer to cancer nanomedicine.

High-throughput tool uncovers links between cell signaling and nanomaterial uptake.

A Novel Silicone Simulation Model for Microvascular Anastomosis.

Purpose: Surgical simulation of microvascular anastomosis has become increasingly popular. There are several living and silicone models available. Current silicone models fail to accurately reproduce a vessel's loose adventitial layer, which may lead to the development of improper microsurgical technique. Our purpose is to create a realistic 3-dimensional microsurgical simulator that incorporates an adventitial vessel layer for higher fidelity manipulation of vessels. Methods: A microvascular anastomosis simulator was manufactured using metal moulds and inorganic materials. Synthetic tubing was created with a metal cylinder, 1.65 mm in diameter, painted with 2 sequential layers of silicon with a shore hardness of 2A. Silicone was allowed to fully cure in-between layers. Vessel adventitia was created with a 100-micron polyester mesh adhered to the silicone vessel exterior. Once dry, the synthetic tube is removed from the metal cylinder is then clipped to reveal the inner lumen. Both Resident and attending physicians evaluated the model with and without the adventitial layer and completed a questionnaire. Results: Grasping and manipulation of the vessel were scored on Average score 4.5 and 3 out of 5, with adventitia and without, respectively (P = .00906). Usefulness as a teaching tool was scored on average 4.9 and 4.2, with adventitia and without, respectively (P = .0232). The analysis included: simulation realism, educational utility, and overall satisfaction. Responses in all domains were favourable, suggesting the utility of this model. Conclusion: We created a realistic, high fidelity microvascular anastomosis simulator that is low cost and easily reproducible. Initial feedback is encouraging regarding realism, educational utility, and overall usefulness. Further validation is required to assess its effectiveness in resident education and skill transfer to the operating room.

Objectif: La simulation chirurgicale de l'anastomose microvasculaire gagne en popularité. Il existe plusieurs modèles de simulation vivants ou en silicone. Les modèles actuels en silicone ne réussissent pas à reproduire la couche adventitielle lâche, ce qui peut entraîner une technique microchirurgicale inappropriée. Les chercheurs voulaient créer un simulateur microchirurgical tridimensionnel réaliste doté d'une couche adventitielle pour manipuler les vaisseaux avec plus de fiabilité. Méthodologie: Les chercheurs ont fabriqué un simulateur d'anastomose microvasculaire au moyen de moules métalliques et de matières inorganiques. Ils ont créé des tubulures synthétiques à l'aide d'un cylindre métallique d'un diamètre de 1,65 mm, qu'ils ont peint de deux couches séquentielles de silicone d'une dureté Shore A de 2. Ils ont laissé le silicone durcir complètement entre les couches et ont créé la couche adventitielle à l'aide d'une maille de polyester de 100 microns fixée à l'extérieur du vaisseau de silicone. Une fois sèche, la tubulure synthétique est retirée du cylindre métallique, puis coupée pour révéler la lumière interne. Des résidents et des médecins traitants ont évalué le modèle avec et sans la couche adventitielle et rempli un questionnaire. Résultats: La saisie et la manipulation du vaisseau ont obtenu un score moyen de 4,5 et de 3 sur 5, avec et sans la couche adventitielle, respectivement (p = 0,00906). L'utilité de ce vaisseau comme outil d'enseignement a obtenu un score moyen de 4,9 et de 4,2, avec et sans la couche adventitielle, respectivement (p = 0,0232). L'analyse incluait le réalisme de la simulation, l'utilité pour l'enseignement et la satisfaction globale. Les réponses étaient favorables dans tous les domaines, ce qui laisse croire à l'utilité du modèle. Conclusion: Les chercheurs ont créé un simulateur d'anastomose microvasculaire haute-fidélité réaliste, à la fois peu coûteux et facile à reproduire. Les premiers commentaires sont encourageants pour ce qui est du réalisme, de l'utilité pour l'enseignement et de l'utilité globale. Son efficacité lors de l'enseignement aux résidents et du transfert du savoir en salle d'opération devra être validée davantage.

Nanoparticles caged with DNA nanostructures.

Nanoparticles (NPs) offer many benefits in biotechnology because of their small size and unique properties. However, many applications require precise positioning of the NPs or biological targeting molecules on their surfaces. DNA cages constructed from DNA tile, origami, or wireframe nanostructures offer a promising path forward because of their simplicity and programmability that can be used to generate complex, dynamic 2D and 3D geometries. Such materials can be used to pattern DNA on NP surfaces and organize NPs into specific supramolecular structures. DNA-caged NPs can be implemented in biosensing and drug delivery applications with cavities precisely designed to encapsulate-specific biomolecules. Ultimately, such approaches provide a springboard for future DNA robot designs that will enable controlled interactions with biological systems.

Comparison of Ceftriaxone and Antipseudomonal ß-Lactam Antibiotics Utilized for Potential AmpC ß-Lactamase-Producing Organisms.

Background: Induction of antibiotic resistance is associated with increased morbidity and mortality in AmpC ß-lactamase producing Enterobacteriaceae. The use of ceftriaxone is controversial for treatment of these organisms due to concerns for inducible resistance. This study was designed to compare treatment failure rates between ceftriaxone and antipseudomonal ß-lactam antibiotics when used as definitive therapy for organisms most commonly associated with chromosomal AmpC ß-lactamase production. Methods: A retrospective, single-center cohort study was performed enrolling patients hospitalized with monomicrobial Enterobacter, Citrobacter, or Serratia spp. infections. The primary objective compared proportion of treatment failure between groups. All patients received either ceftriaxone or an antipseudomonal ß-lactam alone within 24 hours of culture finalization, and with a duration of at least 72 hours for definitive treatment. Treatment failure was defined as either clinical failure (abnormal white blood cell count or temperature on day 7 or 14 post-antibiotics) or microbiologic failure (regrowth of the same organism at same site within 14 or 21 days). Results: Of 192 total patients, treatment failure was observed in 24/71 patients (34%) receiving ceftriaxone and in 42/121 patients (35%) receiving antipseudomonal ß-lactam (P = .98). No difference was observed between clinical or microbiologic failure rates between groups. The ceftriaxone group had significantly more patients undergoing treatment for urinary tract infections (51% vs 17%, P < .001), but treatment failure rates remained similar between groups when comparing infections of all other sources. Conclusion: Ceftriaxone has comparable treatment failure rates to antipseudomonal ß-lactams for susceptible Enterobacteriaceae infections and may be considered as a therapeutic option. Further, prospective research is needed to validate optimal dosing and application in all sites of infection.

The Addition of a Nerve Transfer to the Treatment of Peroneal Neuropathy Secondary to Intraneural Ganglion: Case Series.

ABSTRACT: Peroneal intraneural ganglia are rare, and their management is controversial. Presently, the accepted treatment of intraneural ganglia is decompression and ligation of the articular nerve branch. Although this treatment prevents recurrence of the ganglia, the resultant motor deficit of foot drop in the case of intraneural peroneal ganglia is unsatisfying. Foot drop is classically treated with splinting or tendon transfers to the foot. We have recently published a case report of a peroneal intraneural ganglion treated by transferring a motor nerve branch of flexor hallucis longus into a nerve branch of tibialis anterior muscle in addition to articular nerve branch ligation and decompression of the intraneural ganglion to restore the patient's ability to dorsiflex. We have since performed this procedure on 4 additional patients with appropriate follow-up. Depending on the initial onset of foot drop and time to surgery, nerve transfer from flexor hallucis longus to anterior tibialis nerve branch may be considered as an adjunct to decompression and articular nerve branch ligation for the treatment of symptomatic peroneal intraneural ganglion.

Synthesis of polymer nanoparticles via electrohydrodynamic emulsification-mediated self-assembly.

HYPOTHESIS: Electrospray can rapidly produce fine, organic solvent-in-water emulsions in the absence of surfactant via electrohydrodynamic emulsification (EE), a reverse configuration of traditional electrospray. This paper investigates whether EE can produce high-quality nanocomposites comprised of block co-polymers and organic nanoparticles (NPs) via the interfacial instability (IS) self-assembly method. Surfactant-free approaches may increase encapsulation efficiency and product uniformity, process speed, and ease of downstream product purification. EXPERIMENTS: All particles were produced using EE-mediated self-assembly (SA) (EE-SA). Particles were produced using poly(lactic-co-glycolic acid) (PLGA) polymers as proof of concept. Then, block copolymer (BCP) micelles were synthesized from polystyrene-block-poly(ethylene oxide) (PS-b-PEO) (PS 9.5 kDa:PEO 18.0 kDa) in the presence and absence of superparamagnetic iron oxide nanoparticles (SPIONs) or quantum dots (QDs). Encapsulant concentration was varied, and the effect of encapsulant NP ligands on final particle size was investigated. FINDINGS: EE-SA generated both pure polymer NPs and nanocomposites containing SPIONs and QDs. PLGA particles spanned from sub- to super-micron sizes. PS-b-PEO NPs and nanocomposites were highly monodisperse, and more highly loaded than those made via a conventional, surfactant-rich IS process. Free ligands decreased the size of pure BCP particles. Increasing encapsulant levels led to a morphological transition from spherical to worm-like to densely loaded structures.