High Fat Diet-Induced Obesity Dysregulates Splenic B Cell Mitochondrial Activity.

Diet-induced obesity impairs mitochondrial respiratory responses in tissues that are highly metabolically active, such as the heart. However, less is known about the impact of obesity on the respiratory activity of specific cell types, such as splenic B cells. B cells are of relevance, as they play functional roles in obesity-induced insulin resistance, inflammation, and responses to infection. Here, we tested the hypothesis that high-fat-diet (HFD)-induced obesity could impair the mitochondrial respiration of intact and permeabilized splenic CD19+ B cells isolated from C57BL/6J mice and activated ex vivo with lipopolysaccharide (LPS). High-resolution respirometry was used with intact and permeabilized cells. To reveal potential mechanistic targets by which HFD-induced obesity dysregulates B cell mitochondria, we conducted proteomic analyses and 3D serial block face scanning electron microscopy (SBFEM). High-resolution respirometry revealed that intact LPS-stimulated B cells of obese mice, relative to controls, displayed lower ATP-linked, as well as maximal uncoupled, respiration. To directly investigate mitochondrial function, we used permeabilized LPS-stimulated B cells, which displayed increased H2O2 emission and production with obesity. We also examined oxidative phosphorylation efficiency simultaneously, which revealed that oxygen consumption and ATP production were decreased in LPS-stimulated B cells with obesity relative to controls. Despite minimal changes in total respiratory complex abundance, in LPS-stimulated B cells of obese mice, three of the top ten most downregulated proteins were all accessory subunits of respiratory complex I. SBFEM showed that B cells of obese mice, compared to controls, underwent no change in mitochondrial cristae integrity but displayed increased mitochondrial volume that was linked to bioenergetic function. Collectively, these results establish a proof of concept that HFD-induced obesity dysregulates the mitochondrial bioenergetic metabolism of activated splenic B cells.

Orthopaedic Trauma Association Global Outreach Task Force Proceedings.

Introduction: In 2020, the Orthopaedic Trauma Association (OTA) adopted an updated strategic plan emphasizing global outreach. A task force was appointed to better understand the current global orthopaedic trauma educational demand and how the organization may better partner with our global colleagues. This article provides a description of the process and the results of the findings. Methods: First, the current international demographics of the OTA membership were reviewed. Then, 2 surveys were distributed. The first was sent to all current members of the OTA to determine how important the members believe that global orthopaedics should be to the organization's mission. The second survey was sent out to our international orthopaedic trauma colleagues. The results of both surveys were reviewed, analyzed, and summarized in an executive summary report which was presented to the OTA Board of Directors earlier this year. Results: The responses from the membership survey indicated a keen interest in the development of global outreach within our organization. The global outreach survey received 72 responses from 28 different countries, mostly lower and lower-middle income countries. This included many countries in Asia and Africa who had no prior relationship with the OTA. Most respondents were already using online educational materials and expressed a desire for more high-quality online offerings as well as regional resource-specific orthopaedic trauma courses. Conclusion: The overwhelming majority of member respondents believe that global orthopaedics is highly important and central to our mission. Similarly, a majority of the international respondents believed that global orthopaedics is necessary and worthwhile. They expressed a need for more educational opportunities and collaboration, particularly in the areas of online offerings as well as regional, resource-specific courses.

Impact of a pyridazine derivative on tripartite synapse ultrastructure in hippocampus: a three-dimensional analysis.

Introduction: We previously discovered a pyridazine derivative compound series that can improve cognitive functions in mouse models of Alzheimer's disease. One of the advanced compounds from this series, LDN/OSU-0215111-M3, was selected as the preclinical development candidate. This compound activates local protein translation at the perisynaptic astrocytic process (PAP) and enhances synaptic plasticity sequentially. While biochemical evidence supports the hypothesis that the compound enhances the structural plasticity of the tripartite synapse, its direct structural impact has not been investigated. Methods: Volume electron microscopy was used to study the hippocampal tripartite synapse three-dimensional structure in 3-month-old wild-type FVB/NJ mice after LDN/OSU-0215111-M3 treatment. Results: LDN/OSU-0215111-M3 increased the size of tertiary apical dendrites, the volume of mushroom spines, the proportion of mushroom spines containing spine apparatus, and alterations in the spine distribution across the surface area of tertiary dendrites. Compound also increased the number of the PAP interacting with the mushroom spines as well as the size of the PAP in contact with the spines. Furthermore, proteomic analysis of the isolated synaptic terminals indicated an increase in dendritic and synaptic proteins as well as suggested a possible involvement of the phospholipase D signaling pathway. To further validate that LDN/OSU-0215111-M3 altered synaptic function, electrophysiological studies showed increased long-term potentiation following compound treatment. Discussion: This study provides direct evidence that pyridazine derivatives enhance the structural and functional plasticity of the tripartite synapse.

Renal disease and diabetes increase the risk of failed outpatient management of cellulitic hand infections: a retrospective cohort study.

BACKGROUND: Hand infections are heterogeneous, and some may undergo successful outpatient management. There are no strict guidelines for determining which patients will likely require inpatient admission for successful treatment, and many patients succeed with outpatient therapy. We sought to determine risk factors for failed outpatient management of cellulitic hand infections. METHODS: We performed a retrospective review of patients who presented to the Emergency Department (ED) for hand cellulitic infections over five years, from 2014 to 2019. Vital signs, lab markers, Charlson Comorbidity Index (CCI), Elixhauser Comorbidity Measure (ECM), and antibiotic use were investigated. Discharge from the ED without subsequent admission was considered an outpatient success, while admission within 30 days of the prior visit was considered a failure. Continuous variables were compared with Welch's t test, and categorical data with Fisher's exact tests. Multivariable logistic regression was performed on comorbidities. Multiple testing adjustment was performed on p-values to generate q-values. RESULTS: Outpatient management was attempted for 1,193 patients. 31 (2.6%) infections failed treatment, and 1,162 (97.4%) infections succeeded. Attempted outpatient treatment was 97.4% successful. Multivariable analysis demonstrated higher odds of failure with renal failure according to both CCI (OR 10.2, p < 0.001, q = 0.002) and ECM (OR 12.63, p = 0.003, q = 0.01) and with diabetes with complications according to the CCI (OR 18.29, p = 0.021, q = 0.032). CONCLUSIONS: Outpatient treatment failure was higher in patients with renal failure and complicated diabetes. These patients require a high index of suspicion for outpatient failure. These comorbidities should influence consideration for inpatient therapy though most patients can undergo successful treatment as outpatients. LEVEL OF EVIDENCE: Level III.

Impact of Aluminum Oxide Nanocoating on Drug Release from Amorphous Solid Dispersion Particles.

Atomic layer coating (ALC) is emerging as a particle engineering strategy to inhibit surface crystallization of amorphous solid dispersions (ASDs). In this study, we turn our attention to evaluating drug release behavior from ALC-coated ASDs, and begin to develop a mechanistic framework. Posaconazole/hydroxypropyl methylcellulose acetate succinate was used as a model system at both 25% and 50% drug loadings. ALC-coatings of aluminum oxide up to 40 nm were evaluated for water sorption kinetics and dissolution performance under a range of pH conditions. Scanning electron microscopy with energy dispersive X-ray analysis was used to investigate the microstructure of partially released ASD particles. Coating thickness and defect density (inferred from deposition rates) were found to impact water sorption kinetics. Despite reduced water sorption kinetics, the presence of a coating was not found to impact dissolution rates under conditions where rapid drug release was observed. Under slower releasing conditions, underlying matrix crystallization was reduced by the coating, enabling greater levels of drug release. These results demonstrate that water was able to penetrate through the ALC coating, hydrating the amorphous solid, which can initiate dissolution of drug and/or polymer (depending on pH conditions). Swelling of the ASD substrate subsequently occurs, disrupting and cracking the coating, which serves to facilitate rapid drug release. Water sorption kinetics are highlighted as a potential predictive tool to investigate the coating quality and its potential impact on dissolution performance. This study has implications for formulation design and evaluation of ALC-coated ASD particles.

Atomic Layer Coating to Inhibit Surface Crystallization of Amorphous Pharmaceutical Powders.

Preventing crystallization is a primary concern when developing amorphous drug formulations. Recently, atomic layer coatings (ALCs) of aluminum oxide demonstrated crystallization inhibition of high drug loading amorphous solid dispersions (ASDs) for over 2 years. The goal of the current study was to probe the breadth and mechanisms of this exciting finding through multiple drug/polymer model systems, as well as particle and coating attributes. The model ASD systems selected provide for a range of hygroscopicity and chemical functional groups, which may contribute to the crystallization inhibition effect of the ALC coatings. Atomic layer coating was performed to apply a 5-25 nm layer of aluminum oxide or zinc oxide onto ASD particles, which imparted enhanced micromeritic properties, namely, reduced agglomeration and improved powder flowability. ASD particles were stored at 40 °C and a selected relative humidity level between 31 and 75%. Crystallization was monitored by X-ray powder diffraction and scanning electron microscopy (SEM) up to 48 weeks. Crystallization was observable by SEM within 1-2 weeks for all uncoated samples. After ALC, crystallization was effectively delayed or completely inhibited in some systems up to 48 weeks. The delay achieved was demonstrated regardless of polymer hygroscopicity, presence or absence of hydroxyl functional groups in drugs and/or polymers, particle size, or coating properties. The crystallization inhibition effect is attributed primarily to decreased surface molecular mobility. ALC has the potential to be a scalable strategy to enhance the physical stability of ASD systems to enable high drug loading and enhanced robustness to temperature or relative humidity excursions.

Audiologic Assessment.

Prior to the fitting of hearing aids, clinicians and patients must discuss the best treatment options for the physical and audiologic needs of the patients. To be able to confidently make these decisions, the clinician should complete a medical and audiological case history. Additionally, clinicians need accurate results from a comprehensive audiologic evaluation. The evaluation should include the following: pure-tone testing, word recognition testing, speech-in-noise testing, and loudness discomfort level measures. This article will outline the process and procedures for acquiring this information in line with the Audiology Practice Standards Organization (APSO) Guidelines for Adult Hearing Aid Fittings Standards 1 and 4. This article will also discuss how results can affect decision-making during the hearing aid selection and fitting process.

Short-term Disability Insurance, Return to Work, and the Responsibility of the Orthopaedic Surgeon.

Millions of Americans are unable to work every day because of illness or injury. Many of these individuals have musculoskeletal issues and are under the care of an orthopaedic surgeon. Short-term disability insurance programs have been developed to address the financial burden experienced by workers who are temporarily without income. Private insurance companies and state-sponsored programs are the two most common forms. Most disability plans require verification from a physician that the worker is unable to work or is able to work in a limited capacity. Quite often, this responsibility falls on the orthopaedic surgeon. Our participation is important and substantial, yet we receive little instruction on the role that we play in this process. This article explains the history and development of short-term disability programs, describes the way they currently function in our country, and clarifies the role of the orthopaedic surgeon in the process.

Surfactants Accelerate Crystallization of Amorphous Nifedipine by Similar Enhancement of Nucleation and Growth Independent of Hydrophilic-Lipophilic Balance.

Amorphous formulations, increasingly employed to deliver poorly soluble drugs, generally contain surfactants to improve wetting and dissolution. These surfactants are often liquids and can potentially increase the mobility of the drug and reduce its stability, but little is known about this effect. Here we investigate the effect of four common nonionic surfactants (Tween 80, Span 80, Triton X-100, and Poloxamer 407) on the crystallization of amorphous nifedipine (NIF). We find that the surfactants significantly enhance the rates of crystal nucleation and growth even at low concentrations, by up to 2 orders of magnitude at 10 wt %. The surfactants tested show similar enhancement effects independent of their structural details and hydrophilic-lipophilic balance (HLB), suggesting that surfactant adsorption at solid/liquid interfaces does not play a major role in crystal nucleation and growth. Importantly, the surfactants accelerate crystal nucleation and growth by a similar factor. This result mirrors the previous finding that a polymer dopant in a molecular glass-former causes similar slowdown of nucleation and growth. These results indicate that nucleation and growth in a deeply supercooled liquid are both mobility-limited, and a dopant mainly functions as a mobility modifier (enhancer or suppressor depending on the dopant). The common surfactants tested are all mobility enhancers and destabilize the amorphous drug, and this negative effect must be managed using stabilizers such as polymers. The effect of surfactants on nucleation can be predicted from the effect on crystal growth and the crystallization kinetics of the pure system, using the same principle previously established for drug-polymer systems. We show how the independently measured nucleation and growth rates enable predictions of the overall crystallization rates.

Ultrastructural view of astrocyte arborization, astrocyte-astrocyte and astrocyte-synapse contacts, intracellular vesicle-like structures, and mitochondrial network.

The complexity of astrocyte morphology and syncytial coupling through gap junctions are crucial for astrocyte function in the brain. However, the ultrastructural details of astrocyte arborization and interactions between neighboring astrocytes remain unknown. While a prevailing view is that synapses selectively contact peripheral astrocyte processes, the precise spatial-location selectivity of synapses abutting astrocytes is unresolved. Additionally, knowing the location and quantity of vesicles and mitochondria are prerequisites to answer two emerging questions - whether astrocytes have a signaling role within the brain and whether astrocytes are highly metabolically active. Here, we provided structural context for these questions by tracing and 3D reconstructing three neighboring astrocytes using serial block-face scanning electron microscopy. Our reconstructions reveal a spongiform astrocytic morphology resulting from the abundance of reflexive and leaflet processes. At the interfaces, varying sizes of astrocyte-astrocyte contacts were identified. Inside an astrocyte domain, synapses contact the entire astrocyte, and synapse-astrocyte contacts increase from soma to terminal leaflets. In contrast to densely packed vesicles at synaptic boutons, vesicle-like structures were scant within astrocytes. Lastly, astrocytes contain dense mitochondrial networks with a mitochondrial volume ratio similar to that of neurites. Together, these ultrastructural details should expand our understanding of functional astrocyte-astrocyte and astrocyte-neuron interactions.

Management of postpartum haemorrhage in a patient with Klippel-Trènaunay syndrome.

Klippel-Trènaunay syndrome is a rare congenital disorder characterised by vascular malformations, which may be exacerbated during pregnancy and pose considerable thromboembolic and haemorrhagic risk for obstetric patients. We report on a patient with this syndrome who underwent elective caesarean section which was indicated due to previous obstetric anal sphincter injury. We describe her multidisciplinary preoperative planning and successful management of major postpartum haemorrhage with uterine compression sutures and intrauterine balloon tamponade ('uterine sandwich').

Diversity in orthopaedic trauma: where we are and where we need to be.

Diversity has multiple dimensions, and individuals' interpretation of diversity varies broadly. The Orthopaedic Trauma Association (OTA) leadership recognized the need to address issues of diversity within the organization and appointed the OTA Diversity Committee in 2020. The OTA Diversity Committee has produced a statement that was confirmed by the OTA's board of directors reflecting the organization's position on diversity: "The OTA promotes and values diversity and inclusion at all levels with the goal of creating an environment where every member has the opportunity to excel in leadership, education, and culturally-competent orthopaedic trauma care." The OTA Diversity Committee surveyed its 1907 OTA members in the United States and Canada to assess its membership's attitudes toward and interpretation of this important topic. METHODS: Two surveys were distributed. One 15-question survey was sent to 1907 OTA members with different membership categories in the United States and Canada requesting basic demographic information and asking how members felt about the degree to which women and underrepresented minorities (URM) are represented within the OTA and within its leadership. A second 11-question survey was sent to 30 past chairs of 2017-2019 OTA educational courses and meetings evaluating their criteria for choosing faculty for OTA courses. Comments were reviewed and summarized to identify recurring themes. RESULTS: Two hundred seven responses from the membership and 14 from course chairs were received from the 1907 surveys that were emailed to OTA members in the United States and Canada. The results reveal awareness of the limited female and URM representation within the OTA. However, there is disagreement in how or even whether this should be addressed at an organizational level. Review of comments from both surveys reveals a number of common themes on these important topics. CONCLUSION: The members and course chairs surveyed recognize that there is limited diversity at the OTA leadership and faculty level. Many members feel that the OTA would benefit from increasing female and URM representation in committees, within the leadership, and as faculty at OTA-sponsored courses. However, survey comments reveal that many members and course chairs feel it is not the organization's role to regulate diversity and that diversity initiatives themselves may introduce an unnecessary form of bias.

Managing Lymphedema in Fracture Care: Current Concepts and Treatment Principles.

Lymphatic flow plays a notable role in the regulation of bone formation and remodeling. Chronic accumulation of the lymph fluid within tissues may lead to issues with proper bone healing after fractures, emphasizing the importance of proper management of lymphedema after trauma. Many associated risk factors place patients at risk for lymphedema, including previous surgery with nodal dissection, radiation therapy, infection, malignancy, family history of congenital lymphedema, and trauma. The benchmark imaging technique for the diagnosis of lymphedema is lymphoscintigraphy. Other modalities include duplex ultrasonography, CT, and MRI. First-line conservative treatment of lymphedema is compression. Complete decongestive therapy or complex physical therapy, also known as decongestive lymphatic therapy (DLT), has shown positive results in reducing lymphedema. Surgical interventions aim to either reconstruct and restore function of the lymphatic system or debulk and reduce tissues and fluids. Understanding the significance of lymphedema on bone healing and techniques available to recognize it are important factors in preventing delay in diagnosis and ensuring proper management of lymphedema after trauma.

The cardiolipin-binding peptide elamipretide mitigates fragmentation of cristae networks following cardiac ischemia reperfusion in rats.

Mitochondrial dysfunction contributes to cardiac pathologies. Barriers to new therapies include an incomplete understanding of underlying molecular culprits and a lack of effective mitochondria-targeted medicines. Here, we test the hypothesis that the cardiolipin-binding peptide elamipretide, a clinical-stage compound under investigation for diseases of mitochondrial dysfunction, mitigates impairments in mitochondrial structure-function observed after rat cardiac ischemia-reperfusion. Respirometry with permeabilized ventricular fibers indicates that ischemia-reperfusion induced decrements in the activity of complexes I, II, and IV are alleviated with elamipretide. Serial block face scanning electron microscopy used to create 3D reconstructions of cristae ultrastructure reveals that disease-induced fragmentation of cristae networks are improved with elamipretide. Mass spectrometry shows elamipretide did not protect against the reduction of cardiolipin concentration after ischemia-reperfusion. Finally, elamipretide improves biophysical properties of biomimetic membranes by aggregating cardiolipin. The data suggest mitochondrial structure-function are interdependent and demonstrate elamipretide targets mitochondrial membranes to sustain cristae networks and improve bioenergetic function.

Predictors for Late Post-Intracerebral Hemorrhage Dementia in Patients with Probable Cerebral Amyloid Angiopathy.

BACKGROUND AND OBJECTIVE: Cerebral amyloid angiopathy (CAA) accounts for the majority of lobar intracerebral hemorrhage (ICH); however, the risk factors for dementia conversion after ICH occurrence in CAA patients are unknown, especially in the long-term period after ICH. Therefore, we aimed to unravel the predictors for late post-ICH dementia (6 months after ICH event) in probable CAA patients. METHODS: From a large consecutive MRI prospective cohort of spontaneous ICH (2006-2017), we identified probable CAA patients (modified Boston criteria) without dementia 6 months post-ICH. Cognitive outcome during follow-up was determined based on the information from standardized clinical visit notes. We used Cox regression analysis to investigate the association between baseline demographic characteristics, past medical history, MRI biomarkers, and late post-ICH dementia conversion (dementia occurred after 6 months). RESULTS: Among 97 non-demented lobar ICH patients with probable CAA, 25 patients (25.8%) developed dementia during a median follow-up time of 2.5 years (IQR 1.5-3.8 years). Pre-existing mild cognitive impairment, increased white matter hyperintensities (WMH) burden, the presence of disseminated cortical superficial siderosis (cSS), and higher total small vessel disease score for CAA were all independent predictors for late dementia conversion. CONCLUSION: In probable CAA patients presenting with lobar ICH, high WMH burden and presence of disseminated cSS are useful neuroimaging biomarkers for dementia risk stratification. These findings have implications for clinical practice and future trial design.

Conventional Amplification for Children and Adults with Severe-to-Profound Hearing Loss.

The primary goal of amplification is to restore audibility without causing discomfort; for someone with severe-to-profound hearing loss, the reduced dynamic range poses unique challenges in hearing-assistive device fitting. These challenges, including physiological limitation, processing difficulties, technology constraints, and other confounding factors, must be considered when selecting, fitting, and counseling for appropriate amplification. Many of the advanced features in hearing aids do not adequately address the unique characteristics of patients with severe-to-profound hearing loss. This review article will attempt to unravel some of the challenges and associated considerations when fitting adults and children with severe-to-profound hearing loss.

Visualizing melanosomes, lipofuscin, and melanolipofuscin in human retinal pigment epithelium using serial block face scanning electron microscopy.

To assess serial section block-face scanning electron microscopy (SBFSEM) for retinal pigment epithelium (RPE) ultrastructure, we determined the number and distribution within RPE cell bodies of melanosomes (M), lipofuscin (L), and melanolipofuscin (ML). Eyes of 4 Caucasian donors (16M, 32F, 76F, 84M) with unremarkable maculas were sectioned and imaged using an SEM fitted with an in-chamber automated ultramicrotome. Aligned image stacks were generated by alternately imaging an epoxy resin block face using backscattered electrons, then removing a 125 nm-thick layer. Series of 249-499 sections containing 5-24 nuclei were examined per eye. Trained readers manually assigned boundaries of individual cells and x,y,z locations of M, L, and ML. A Density Recovery Profile was computed in three dimensions for M, L, and ML. The number of granules per RPE cell body in 16M, 32F, 76F, and 84M eyes, respectively, was 465 ± 127 (mean ± SD), 305 ± 92, 79 ± 40, and 333 ± 134 for L; 13 ± 9; 6 ± 7, 131 ± 55, and 184 ± 66 for ML; and 29 ± 19, 24 ± 12, 12 ± 7, and 7 ± 3 for M. Granule types were spatially organized, with M near apical processes. The effective radius, a sphere of decreased probability for granule occurrence, was 1 µm for L, ML, and M combined. In conclusion, SBFEM reveals that adult human RPE has hundreds of L, LF, and M and that granule spacing is regulated by granule size alone. When obtained for a larger sample, this information will enable hypothesis testing about organelle turnover and regulation in health, aging, and disease, and elucidate how RPE-specific signals are generated in clinical optical coherence tomography and autofluorescence imaging.

Analysis of Brain Mitochondria Using Serial Block-Face Scanning Electron Microscopy.

Human brain is a high energy consuming organ that mainly relies on glucose as a fuel source. Glucose is catabolized by brain mitochondria via glycolysis, tri-carboxylic acid (TCA) cycle and oxidative phosphorylation (OXPHOS) pathways to produce cellular energy in the form of adenosine triphosphate (ATP). Impairment of mitochondrial ATP production causes mitochondrial disorders, which present clinically with prominent neurological and myopathic symptoms. Mitochondrial defects are also present in neurodevelopmental disorders (e.g. autism spectrum disorder) and neurodegenerative disorders (e.g. amyotrophic lateral sclerosis, Alzheimer's and Parkinson's diseases). Thus, there is an increased interest in the field for performing 3D analysis of mitochondrial morphology, structure and distribution under both healthy and disease states. The brain mitochondrial morphology is extremely diverse, with some mitochondria especially those in the synaptic region being in the range of <200 nm diameter, which is below the resolution limit of traditional light microscopy. Expressing a mitochondrially-targeted green fluorescent protein (GFP) in the brain significantly enhances the organellar detection by confocal microscopy. However, it does not overcome the constraints on the sensitivity of detection of relatively small sized mitochondria without oversaturating the images of large sized mitochondria. While serial transmission electron microscopy has been successfully used to characterize mitochondria at the neuronal synapse, this technique is extremely time-consuming especially when comparing multiple samples. The serial block-face scanning electron microscopy (SBFSEM) technique involves an automated process of sectioning, imaging blocks of tissue and data acquisition. Here, we provide a protocol to perform SBFSEM of a defined region from rodent brain to rapidly reconstruct and visualize mitochondrial morphology. This technique could also be used to provide accurate information on mitochondrial number, volume, size and distribution in a defined brain region. Since the obtained image resolution is high (typically under 10 nm) any gross mitochondrial morphological defects may also be detected.