Advances in imaging of chemically reacting flows.

Many important chemically reacting systems are inherently multi-dimensional with spatial and temporal variations in the thermochemical state, which can be strongly coupled to interactions with transport processes. Fundamental insights into these systems require multi-dimensional measurements of the thermochemical state as well as fluid dynamics quantities. Laser-based imaging diagnostics provide spatially and temporally resolved measurements that help address this need. The state of the art in imaging diagnostics is continually progressing with the goal of attaining simultaneous multi-parameter measurements that capture transient processes, particularly those that lead to stochastic events, such as localized extinction in turbulent combustion. Development efforts in imaging diagnostics benefit from advances in laser and detector technology. This article provides a perspective on the progression of increasing dimensionality of laser-based imaging diagnostics and highlights the evolution from single-point measurements to 1D and 2D multi-parameter imaging and 3D high-speed imaging. This evolution is demonstrated using highlights of laser-based imaging techniques in combustion science research as an exemplar of a complex multi-dimensional chemically reacting system with chemistry-transport coupling. Imaging diagnostics impact basic research in other chemically reacting systems as well, such as measurements of near-surface gases in heterogeneous catalysis. The expanding dimensionality of imaging diagnostics leads to larger and more complex datasets that require increasingly demanding approaches to data analysis and provide opportunities for increased collaboration between experimental and computational researchers in tackling these challenges.

The Mark Coventry, MD, Award: Oral Antibiotics Reduce Reinfection After Two-Stage Exchange: A Multicenter, Randomized Controlled Trial.

BACKGROUND: Many patients develop recurrent periprosthetic joint infection after two-stage exchange arthroplasty of the hip or knee. One potential but insufficiently tested strategy to decrease the risk of persistent or recurrent infection is to administer additional antibiotics after the second-stage reimplantation. QUESTIONS/PURPOSES: (1) Does a 3-month course of oral antibiotics decrease the risk of failure secondary to infection after a two-stage exchange? (2) Are there any complications related to the administration of oral antibiotics after a two-stage exchange? (3) In those patients who develop a reinfection, is the infecting organism different from the initial infection? METHODS: Patients at seven centers randomized to receive 3 months of oral antibiotics or no further antibiotic treatment after operative cultures after the second-stage reimplantation were negative. Adult patients undergoing two-stage hip or knee revision arthroplasty for a periprosthetic infection who met Musculoskeletal Infection Society (MSIS) criteria for infection at the first stage were included. Oral antibiotic therapy was tailored to the original infecting organism(s) in consultation with an infectious disease specialist. MSIS criteria as used by the treating surgeon defined failure. Surveillance of patients for complications, including reinfection, occurred at 3 weeks, 6 weeks, 3 months, 12 months, and 24 months. If an organism demonstrated the same antibiotic sensitivities as the original organism, it was considered the same organism; no DNA subtyping was performed. Analysis was performed as intent to treat with all randomized patients included in the groups to which they were randomized. A log-rank survival curve was used to analyze the primary outcome of reinfection. At planned interim analysis (enrollment is ongoing), 59 patients were successfully randomized to the antibiotic group and 48 patients to the control group. Fifty-seven patients had an infection after TKA and 50 after a THA. There was no minimum followup for inclusion in this analysis. The mean followup was 14 months in the antibiotic group and 10 months in the control group. RESULTS: Patients treated with oral antibiotics failed secondary to infection less frequently than those not treated with antibiotics (5% [three of 59] versus 19% [nine of 48]; hazard ratio, 4.37; 95% confidence interval, 1.297-19.748; p = 0.016). Three patients had an adverse reaction to the oral antibiotics severe enough to cause them to stop taking the antibiotics early, and four patients who were randomized to that group did not take the antibiotics as directed. With the numbers available, there were no differences between the study groups in terms of the likelihood that an infection after treatment would be with a new organism (eight of nine in the control group versus one of three in the treatment group, p = 0.087). CONCLUSIONS: This multicenter randomized trial suggests that at short-term followup, the addition of 3 months of oral antibiotics appeared to improve infection-free survival. As a planned interim analysis, however, these results may change as the study reaches closure and the safety profile may yet prove risky. Further followup of this cohort of patients will be necessary to determine whether these preliminary results are durable over time. LEVEL OF EVIDENCE: Level I, therapeutic study.

Quantification and correlation of hip capsular volume to demographic and radiographic predictors.

PURPOSE: The purpose of this study was to develop a novel method to quantify hip capsular volume in patients undergoing hip arthroscopic surgery, utilizing magnetic resonance arthrogram (MRA) and to determine whether there are demographic or radiological factors that are associated with capsular volume. METHODS: A retrospective review was performed from 2006 to 2014 of consecutive patients who presented with hip pain and received a hip MRA and plain radiographs. All patients were suspected of soft tissue injury due to underlying femoroacetabular impingement (FAI). A novel technique using Osirix MD for the quantification of capsular and femoral head volumes was described. RESULTS: Ninety-seven patients met the study criteria and were included for analysis. The average total capsular volume (including the femoral head) measured 79.89 ± 20.35 cm(3), average femoral head volume 46.68 ± 12.32 cm(3), and average true capsular volume measured 33.20 ± 12.58 cm(3). Average total capsular:femoral head volume ratio was 1.74 ± 0.27. Significant differences were seen between genders for total capsular volume (P < 0.01), femoral head volume (P < 0.01), and true capsular volume (P < 0.01). Total capsular volume:femoral head ratio was greater for females, but was not statistically significant (n.s.). Femoral head volume significantly correlated with alpha angle (P < 0.01), height (P < 0.01), BMI (P < 0.01), BMI (P = 0.02), and age (P < 0.01). Total capsular volume significantly correlated with height (P < 0.01), BMI (P = 0.01), and age (P < 0.01). Age was also correlated with true capsular volume (P = 0.011). No significant differences in capsular volumes were found between normal and abnormal radiographic measurements. CONCLUSION: The current study describes a reproducible radiographic measurement for hip capsule volumes from MRAs. Only gender was predictive of total capsular volume, femoral head volume, and true capsular volume. There were no macroscopic anatomical differences evident on MRA. This method showed good intra- and inter-observer reliability and can aid in future research regarding hip capsule volumes. This novel technique may potentially allow clinicians a readily available and reliable method to detect large and redundant capsules, a possible predisposition for hip micro-instability. LEVEL OF EVIDENCE: Retrospective case series, Level IV.

Synovial Chondromatosis of the Elbow With Asymptomatic Ulnar Nerve Compression.

Primary synovial chondromatosis is a rare, benign, proliferative disease of hyaline cartilaginous bodies within the synovium of joints. We report a rare case of primary synovial chondromatosis diffusely affecting the ulnohumeral joint causing pain and motion limitations with extrusion into the cubital tunnel and compressing the ulnar nerve but without any preoperative signs or symptoms of ulnar nerve compression. The patient was successfully treated with an open synovectomy to limit disease progression and improve motion. This case highlights that synovial conditions of the elbow may involve the ulnar nerve even when a patient is asymptomatic. Preoperative use of magnetic resonance imaging of the elbow should be considered in patients undergoing either an open or arthroscopic synovectomy.

Articular shear injuries of the capitellum in adolescents.

BACKGROUND: Fractures of the capitellum are rare and are commonly classified into 4 types. Type II variants involve a shear injury with a mostly articular cartilage component and little subchondral bone. Symptoms upon presentation after these injuries are variable, and the diagnosis can be difficult to make in the immature skeleton. METHODS: We retrospectively reviewed 3 cases of type II capitellar fractures in adolescent athletes who presented for evaluation with the senior author. RESULTS: All patients were initially treated conservatively, without identification or treatment of the capitellar shear component of their injury. Unfortunately, radiocapitellar arthrosis rapidly developed in all 3 and required surgical intervention at our institution. At an average postoperative follow-up of 49 months from the index procedure, patients ultimately had positive outcomes despite advanced degenerative changes on imaging. One patient required 2 subsequent operations for mechanical symptoms and pain. DISCUSSION: The 3 reported cases represent adolescent, athletic patients with missed shear injuries to the capitellum. These patients exhibited low Disabilities of Arm, Shoulder and Hand scores and high Mayo Elbow Performance Scores at final follow-up, but each patient demonstrated advanced degenerative changes on imaging, and 1 patient required 2 subsequent operations for mechanical symptoms and pain. A high index of suspicion is necessary to identify this injury pattern, and proper plain radiographic imaging with a low threshold for advanced imaging is necessary. Although the overall long-term prognosis is unknown for these patients, early recognition likely would have changed the initial conservative management decision in each and, theoretically, might have altered the outcome for these patients.

Prevalence of Femoroacetabular Impingement Imaging Findings in Asymptomatic Volunteers: A Systematic Review.

PURPOSE: The aim of this study was to determine the prevalence of radiographic findings suggestive of femoroacetabular impingement (FAI) in asymptomatic individuals. METHODS: A systematic review was performed using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies reporting radiographic, computed tomographic, or magnetic resonance imaging (MRI) findings that were suggestive of FAI in asymptomatic volunteers were included. Cam, pincer, and combined pathologic conditions were investigated. RESULTS: We identified 26 studies for inclusion, comprising 2,114 asymptomatic hips (57.2% men; 42.8% women). The mean participant age was 25.3 ± 1.5 years. The mean alpha angle in asymptomatic hips was 54.1° ± 5.1°. The prevalence of an asymptomatic cam deformity was 37% (range, 7% to 100% between studies)-54.8% in athletes versus 23.1% in the general population. Of the 17 studies that measured alpha angles, 9 used MRI and 9 used radiography (1 study used both). The mean lateral and anterior center edge angles (CEAs) were 31.2° and 30°, respectively. The prevalence of asymptomatic hips with pincer deformity was 67% (range 61% to 76% between studies). Pincer deformity was poorly defined (4 studies [15%]; focal anterior overcoverage, acetabular retroversion, abnormal CEA or acetabular index, coxa profunda, acetabular protrusio, ischial spine sign, crossover sign, and posterior wall sign). Only 7 studies reported on labral injury, which was found on MRI without intra-articular contrast in 68.1% of hips. CONCLUSIONS: FAI morphologic features and labral injuries are common in asymptomatic patients. Clinical decision making should carefully analyze the association of patient history and physical examination with radiographic imaging. LEVEL OF EVIDENCE: Level IV, systematic review if Level II-IV studies.

Two cases of avascular necrosis after prophylactic pinning of the asymptomatic, contralateral femoral head for slipped capital femoral epiphysis: case report and review of the literature.

BACKGROUND: In a child with a unilateral slipped capital femoral epiphysis (SCFE), the treatment of the radiographically normal, asymptomatic contralateral hip remains controversial. The risks of a subsequent slip have to be measured against the risks involved with an additional surgical procedure. Proponents of prophylactic pinning believe that fixation with a single cannulated screw is a safe method to prevent secondary arthrosis from a missed minor slip. Others argue that in most cases it is an unnecessary procedure and with careful follow-up, any issues with the asymptomatic, normal hip can be identified early and addressed. METHODS: We retrospectively look at 2 cases where avascular necrosis (AVN) developed in the prophylactically pinned asymptomatic and radiographically normal hip in the setting of an identified SCFE on the contralateral hip. RESULTS: Two cases of AVN developed in the prophylactically pinned hips within 8 months of the initial pinning procedure. CONCLUSIONS: This case report demonstrates that prophylactic pinning of an asymptomatic, radiographically normal hip in the setting of a SCFE on the contralateral side is not a benign procedure and is one that has potential for significant complications. The risk of AVN in the prophylactically pinned hip needs to be taken into careful consideration as this risk can have devastating consequences to the patient. LEVEL OF EVIDENCE: Level IV.

Utility of modern arthroscopic simulator training models.

PURPOSE: The purpose of this study was to review the published literature on modern arthroscopic simulator training models to (1) determine the ability to transfer skills learned on the model to the operating room and (2) determine the learning curve required to translate such skills. METHODS: A systematic review of all studies using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines was performed. Two independent reviewers then analyzed studies deemed appropriate for inclusion. Study data collected included participant demographic characteristics, simulator model, type and number of tasks, method of analysis, and results of training, when available. Given the different methods used in each study, descriptive analysis was performed. RESULTS: Nineteen studies met the inclusion criteria (9 shoulder, 9 knee, and 1 hip). A total of 465 participants with a mean age of 30 years were evaluated. Twelve studies (63%) compared task performance among participants of different experience levels, with 100% reporting a positive correlation between experience level and simulator performance. Eight studies (42%) evaluated task performance before and after simulator training, with 6 studies showing improvement after training; 1 study noted no difference in performance after 1 hour of training. One study commented on improved operating room performance after simulator training. No studies commented on the number of training sessions needed to translate skills learned on the models to the operating room. CONCLUSIONS: This review suggests that practice on arthroscopic simulators improves performance on arthroscopic simulators. We cannot, however, definitively comment on whether simulator training correlates to an improved skill set in the operating room. Further work is needed to determine the type and number of training sessions needed to translate arthroscopic skills learned on the models to the operating room. LEVEL OF EVIDENCE: Level IV, systematic review of studies with Level I through IV evidence.

Clarifying the butter Boletes: a new genus, Butyriboletus, is established to accommodate Boletus sect. Appendiculati, and six new species are described.

The butter boletes (Boletus s.l. sect. Appendiculati) are an economically important group of ectomycorrhizal fungi whose basidiocarps have a yellow tube layer that often bruises blue, yellow reticulate stipe, mild flavor and firm yellow-tinged flesh that may or may not turn blue when exposed. Morphological characters and molecular data (ITS and LSU) place this group in a separate phylogenetic clade from Boletus sensu stricto. Here we establish a new genus, Butyriboletus, to accommodate 14 species of butter boletes that range from Asia to Europe, north Africa and North America. We recombine eight previously described butter bolete species and we describe six new species: four from western USA (Bu. persolidus, Bu. primiregius, Bu. autumnigius, Bu. querciregius) and two from Yunnan, China (Bu. yicibus, Bu. sanicibus).

Evidence of capsular defect following hip arthroscopy.

PURPOSE: The purpose of this study is to identify the incidence of capsular defects in patients undergoing revision hip arthroscopy. METHODS: A radiographic and anatomical analysis of MR arthrograms of patients undergoing revision arthroscopy was performed to assess for the presence of capsular defect. Intra-operative images and findings were reviewed. Patients with persistent cam and pincer lesions were excluded. RESULTS: From October 2011 to October 2012, 25 patients underwent revision hip arthroscopy surgery, and 9 patients met our inclusion criteria. Within this series, all patients had post-surgical capsular irregularities and seven patients (78 %) had radiographic evidence of capsule and iliofemoral defects on MR arthrogram. Gross capsular defects were confirmed at revision surgery in two patients. CONCLUSION: The findings of this study demonstrate post-surgical radiographic and anatomical evidence of capsular defects in a select group of patients following hip arthroscopy.

Spatiotemporal uptake characteristics of [18]F-2-fluoro-2-deoxy-D-glucose in a rat middle cerebral artery occlusion model.

BACKGROUND AND PURPOSE: Alterations of cerebral glucose metabolism are well anticipated during cerebral ischemia. However, detailed spatiotemporal characteristics of disturbed cerebral glucose metabolism during acute ischemia remain largely elusive. This study aims to delineate spatiotemporal distributions of [18]F-2-fluoro-2-deoxy-D-glucose (FDG) uptake using positron emission tomography imaging, particularly at the peri-ischemic zone, and its correlation with tissue outcome. METHODS: The intraluminal suture middle cerebral artery occlusion model was used to induce focal cerebral ischemia in rats (n=48). All animals underwent sequential MRI and FDG positron emission tomography imaging at different times (30-150 minutes) after middle cerebral artery occlusion. MR and positron emission tomography images were coregistered. FDG uptake in the peri-ischemic zone was assessed in relation to middle cerebral artery occlusion duration, cerebral blood flow, apparent diffusion coefficient, and 24-hour T2 lesions. RESULTS: Elevated FDG uptake was consistently observed at the peri-ischemic zone surrounding the presumed ischemic core with low FDG uptake. Both the spatial volume and the uptake level of the hyper-uptake region were inversely correlated with the duration of middle cerebral artery occlusion. The hyper-uptake regions exhibited a mild reduction of cerebral blood flow (28.2±3.2%) and apparent diffusion coefficient (9.1±1.4%) when compared with that in the contralateral hemisphere. Colocalization analysis revealed that, with reperfusion, an average of 12.1±1.7% of the hyper-uptake volume was recruited into final infarction. CONCLUSIONS: Elevated FDG uptake at the peri-ischemic zone is consistently observed during acute cerebral ischemia. The region with elevated FDG uptake likely reflects viable tissues that can be salvaged with reperfusion. Therefore, acute FDG positron emission tomography imaging might hold promise in the management of patients with acute stroke.

In-vivo detection of white adipose tissue browning: a multimodality imaging approach.

Detection and differentiation of brown fat in humans poses several challenges, as this tissue is sparse and often mixed with white adipose tissue. Non-invasive detection of beige fat represents an even greater challenge as this tissue is structurally and functionally more like white fat than brown fat. Here we used positron emission tomography with 18F-fluorodeoxyglucose, computed tomography, xenon-enhanced computed tomography, and dynamic contrast-enhanced ultrasound, to non-invasively detect functional and structural changes associated with the browning process of inguinal white fat, induced in mice by chronic stimulation with the ß3-adrenergic receptor agonist CL-316243. These studies reveal a very heterogeneous increase in baseline tissue radiodensity and xenon-enhanced radiodensity, indicative of both an increase in adipocytes water and protein content as well as tissue perfusion, mostly in regions that showed enhanced norepinephrine-stimulated perfusion before CL-316243 treatment. No statistically significant increase in 18F-fluorodeoxyglucose uptake or norepinephrine-stimulated tissue perfusion were observed in the mice after the CL-316243 treatment. The increase in tissue-water content and perfusion, along with the negligible increase in the tissue glucose uptake and norepinephrine-stimulated perfusion deserve more attention, especially considering the potential metabolic role that this tissue may play in whole body metabolism.

Pegloticase co-administered with high MW polyethylene glycol effectively reduces PEG-immunogenicity and restores prolonged circulation in mouse.

The interactions between polymers and the immune system remains poorly controlled. In some instances, the immune system can produce antibodies specific to polymer constituents. Indeed, roughly half of pegloticase patients without immunomodulation develop high titers of anti-PEG antibodies (APA) to the PEG polymers on pegloticase, which then quickly clear the drug from circulation and render the gout treatment ineffective. Here, using pegloticase as a model drug, we show that addition of high molecular weight (MW) free (unconjugated) PEG to pegloticase allows us to control the immunogenicity and mitigates APA induction in mice. Compared to pegloticase mixed with saline, mice repeatedly dosed with pegloticase containing different MW or amount of free PEG possessed 4- to 12- fold lower anti-PEG IgG, and 6- to 10- fold lower anti-PEG IgM, after 3 rounds of pegloticase dosed every 2 weeks. The markedly reduced APA levels, together with competitive inhibition by free PEG, restored the prolonged circulation of pegloticase to levels observed in APA-naïve animals. In contrast, mice with pegloticase-induced APA eliminated nearly all pegloticase from the circulation within just four hours post-injection. These results support the growing literature demonstrating free PEG may effectively suppress drug-induced APA, which in turn may offer sustained therapeutic benefits without requiring broad immunomodulation. We also showed free PEG effectively blocked the PEGylated protein from binding with cells expressing PEG-specific B cell receptors. It provides a template of how we may be able to tune the interactions and immunogenicity of other polymer-modified therapeutics. STATEMENT OF SIGNIFICANCE: A major challenge with engineering materials for drug delivery is their interactions with the immune system. For instance, our body can produce high levels of anti-PEG antibodies (APA). Unfortunately, the field currently lack tools to limit immunostimulation or overcome pre-existing anti-PEG antibodies, without using broad immunosuppression. Here, we showed that simply introducing free PEG into a clinical formulation of PEG-uricase can effectively limit induction of anti-PEG antibodies, and restore their prolonged circulation upon repeated dosing. Our work offers a readily translatable method to safely and effectively restore the use PEG-drugs in patients with PEG-immunity, and provides a template to use unconjugated polymers with low immunogenicity to regulate interactions with the immune system for other polymer-modified therapeutics.

In vivo imaging of brown adipose tissue vasculature reactivity during adrenergic stimulation of non-shivering thermogenesis in mice.

Brown adipose tissue (BAT) is a fat tissue specialized in heat production (non-shivering thermogenesis) and used by mammals to defend core body temperature when exposed to cold. Several studies have shown that during non-shivering thermogenesis the increase in BAT oxygen demand is met by a local and specific increase in tissue's blood flow. While the vasculature of BAT has been extensively studied postmortem in rodents using histology, optical and CT imaging techniques, vasculature changes during stimulation of non-shivering thermogenesis have never been directly detected in vivo. Here, by using computed tomography (CT) angiography with gold nanoparticles we investigate, non-invasively, changes in BAT vasculature during adrenergic stimulation of non-shivering thermogenesis by norepinephrine, a vasoconstrictor known to mediate brown fat heat production, and by CL 316,243, a specific ß3-adrenergic agonist also known to elicit BAT thermogenesis in rodents. We found that while CL 316,243 causes local vasodilation in BAT, with little impact on the rest of the vasculature throughout the body, norepinephrine leads to local vasodilation in addition to peripheral vasoconstriction. As a result, a significantly greater relative increase in BAT perfusion is observed following the injection of NE compared to CL. This study demonstrates the use of in vivo CT angiography as an effective tool in assessing vascular reactivity in BAT both qualitatively and quantitatively in preclinical studies.

A PBPK model recapitulates early kinetics of anti-PEG antibody-mediated clearance of PEG-liposomes.

PEGylation is routinely used to extend the systemic circulation of various protein therapeutics and nanomedicines. Nonetheless, mounting evidence is emerging that individuals exposed to select PEGylated therapeutics can develop antibodies specific to PEG, i.e., anti-PEG antibodies (APA). In turn, APA increase both the risk of hypersensitivity to the drug as well as potential loss of efficacy due to accelerated blood clearance of the drug. Despite the broad implications of APA, the timescales and systemic specificity by which APA can alter the pharmacokinetics and biodistribution of PEGylated drugs remain not well understood. Here, we developed a physiologically based pharmacokinetic (PBPK) model designed to resolve APA's impact on both early- and late-phase pharmacokinetics and biodistribution of intravenously administered PEGylated drugs. Our model accurately recapitulates PK and biodistribution data obtained from PET/CT imaging of radiolabeled PEG-liposomes and PEG-uricase in mice with and without APA, as well as serum levels of PEG-uricase in humans. Our work provides another illustration of the power of high-resolution PBPK models for understanding the pharmacokinetic impacts of anti-drug antibodies and the dynamics with which antibodies can mediate clearance of foreign species.

Biodistribution of Biomimetic Drug Carriers, Mononuclear Cells, and Extracellular Vesicles, in Nonhuman Primates.

Discovery of novel drug delivery systems to the brain remains a key task for successful treatment of neurodegenerative disorders. Herein, the biodistribution of immunocyte-based carriers, peripheral blood mononuclear cells (PBMCs), and monocyte-derived EVs are investigated in adult rhesus macaques using longitudinal PET/MRI imaging. 64 Cu-labeled drug carriers are introduced via different routes of administration: intraperitoneal (IP), intravenous (IV), or intrathecal (IT) injection. Whole body PET/MRI (or PET/CT) images are acquired at 1, 24, and 48 h post injection of 64 Cu-labeled drug carriers, and standardized uptake values (SUVmean and SUVmax ) in the main organs are estimated. The brain retention for both types of carriers increases based on route of administration: IP < IV < IT. Importantly, a single IT injection of PBMCs produces higher brain retention compared to IT injection of EVs. In contrast, EVs show superior brain accumulation compared to the cells when administered via IP and IV routes, respectively. Finally, a comprehensive chemistry panel of blood samples demonstrates no cytotoxic effects of either carrier. Overall, living cells and EVs have a great potential to be used for drug delivery to the brain. When identifying the ideal drug carrier, the route of administration could make big differences in CNS drug delivery.

Defenestrated endothelium delays liver-directed gene transfer in hemophilia A mice.

Hemophilia A is an inherited bleeding disorder caused by defective or deficient coagulation factor VIII (FVIII) activity. Until recently, the only treatment for prevention of bleeding involved IV administration of FVIII. Gene therapy with adeno-associated vectors (AAVs) has shown some efficacy in patients with hemophilia A. However, limitations persist due to AAV-induced cellular stress, immunogenicity, and reduced durability of gene expression. Herein, we examined the efficacy of liver-directed gene transfer in FVIII knock-out mice by AAV8-GFP. Surprisingly, compared with control mice, FVIII knockout (F8TKO) mice showed significant delay in AAV8-GFP transfer in the liver. We found that the delay in liver-directed gene transfer in F8TKO mice was associated with absence of liver sinusoidal endothelial cell (LSEC) fenestration, which led to aberrant expression of several sinusoidal endothelial proteins, causing increased capillarization and decreased permeability of LSECs. This is the first study to link impaired liver-directed gene transfer to liver-endothelium maladaptive structural changes associated with FVIII deficiency in mice.

Linking mycorrhizas to sporocarps: a new species, Geopora cercocarpi, on Cercocarpus ledifolius (Rosaceae).

Mycorrhizal assemblages characterized by molecular data frequently differ from collections of mycorrhizal sporocarps at the same site. Geopora species are frequent mycobionts of ectomycorrhizal roots, but except for G. cooperi they are rarely identified to species by molecular methods. Among the mycobionts of ectomycorrhizas with Cercocarpus ledifolius (Rosaceae) was a fungal species with a 91% BLAST match to G. arenicola. To determine the species of Geopora we surveyed for hypogeous sporocarps under C. ledifolius at sites in southern Oregon where the Geopora mycorrhizas had been collected and identified by DNA sequences of the ITS region. We found sporocarps of a Geopora species with 100% BLAST match to the mycorrhizas. Morphological characters of a white hymenium, inrolled entire margin and large spores, along with a hypogeous habit and a mycorrhizal host of C. ledifolius, distinguished these specimens from previously described species. Here we describe a new species, Geopora cercocarpi.

Near-Surface Gas-Phase Methoxymethanol Is Generated by Methanol Oxidation over Pd-Based Catalysts.

Catalytic conversion of alcohols underlies many commodity and fine chemical syntheses, but a complete mechanistic understanding is lacking. We examined catalytic oxidative conversion of methanol near atmospheric pressure using operando small-aperture molecular beam time-of-flight mass spectrometry, interrogating the gas phase 500 µm above Pd-based catalyst surfaces. In addition to a variety of stable C1-3 species, we detected methoxymethanol (CH3OCH2OH)─a rarely observed and reactive C2 oxygenate that has been proposed to be a critical intermediate in methyl formate production. Methoxymethanol is observed above Pd, AuxPdy alloys, and oxide-supported Pd (common methanol oxidation catalysts). Experiments establish temperature and reactant feed ratio dependences of methoxymethanol generation, and calculations using density functional theory are used to examine the energetics of its likely formation pathway. These results suggest that future development of catalysts and microkinetic models for methanol oxidation should be augmented and constrained to accommodate the formation, desorption, adsorption, and surface reactions involving methoxymethanol.

High MW polyethylene glycol prolongs circulation of pegloticase in mice with anti-PEG antibodies.

Pegloticase is an enzyme used to reduce serum uric acid levels in patients with chronic, treatment-refractory gout. Clinically, about 40% of patients develop high titers of anti-PEG antibodies (APA) after initial treatment, which in turn quickly eliminate subsequent doses of pegloticase from the systemic circulation and render the treatment ineffective. We previously found that pre-infusion with high MW free PEG (40 kDa) can serve as a decoy to saturate circulating APA, preventing binding to a subsequently administered dose of PEG-liposomes and restoring their prolonged circulation in mice, without any detectible toxicity. Here, we investigated the use of 40 kDa free PEG to restore the circulation of radio-labeled pegloticase in mice using longitudinal Positron Emission Tomography (PET) imaging over 4 days. Mice injected with pegloticase developed appreciable APA titers by Day 9, which further increased through Day 14. Compared to naïve mice, mice with pegloticase-induced APA rapidly cleared 89Zr-labeled pegloticase, with ~75% lower pegloticase concentrations in the circulation at four hours after treatment. The 96-h AUC in APA+ mice was less than 30% of the AUC in naïve mice. In contrast, pre-infusion of free PEG into PEG-sensitized mice restored the AUC of pegloticase to ~80% of that seen in naïve mice, resulting in a similar biodistribution to pegloticase in naïve mice over time. These results suggest that pre-infusion of free PEG may be a promising strategy to enable the safe and efficacious use of pegloticase and other PEGylated drugs in patients that have previously failed therapy due to induced APA.