Differentiation state and culture conditions impact neural stem/progenitor cell-derived extracellular vesicle bioactivity.

Extracellular vesicles (EVs) derived from neural progenitor/stem cells (NPSCs) have shown promising efficacy in a variety of preclinical models. However, NPSCs lack critical neuroregenerative functionality such as myelinating capacity. Further, culture conditions used in NPSC EV production lack standardization, limiting reproducibility challenging and potentially potency of the overall approach via lack of optimization. Here, we assessed whether oligodendrocyte precursor cells (OPCs) and immature oligodendrocytes (iOLs), which are further differentiated than NPSCs and which both give rise to mature myelinating oligodendrocytes, could yield EVs with neurotherapeutic properties comparable or superior to those from NPSCs. We additionally examined the effects of extracellular matrix (ECM) coating materials and the presence or absence of growth factors in cell culture on the ultimate properties of EVs. The data show that OPC EVs and iOL EVs performed similarly to NPSC EVs in cell proliferation and anti-inflammatory assays, but NPSC EVs performed better in a neurite outgrowth assay. Additionally, the presence of nerve growth factor (NGF) in culture was found to maximize NPSC EV bioactivity among the conditions tested. NPSC EVs produced under rationally-selected culture conditions (fibronectin + NGF) enhanced axonal regeneration and muscle reinnervation in a rat nerve crush injury model. These results highlight the need for standardization of culture conditions for neurotherapeutic NPSC EV production.

Pharmacological Characterization of a Novel 5-Hydroxybenzothiazolone-Derived ß 2-Adrenoceptor Agonist with Functional Selectivity for Anabolic Effects on Skeletal Muscle Resulting in a Wider Cardiovascular Safety Window in Preclinical Studies.

The anabolic effects of ß 2-adrenoceptor (ß 2-AR) agonists on skeletal muscle have been demonstrated in various species. However, the clinical use of ß 2-AR agonists for skeletal muscle wasting conditions has been limited by their undesired cardiovascular effects. Here, we describe the preclinical pharmacological profile of a novel 5-hydroxybenzothiazolone (5-HOB) derived ß 2-AR agonist in comparison with formoterol as a representative ß 2-AR agonist that have been well characterized. In vitro, 5-HOB has nanomolar affinity for the human ß 2-AR and selectivity over the ß 1-AR and ß 3-AR. 5-HOB also shows potent agonistic activity at the ß 2-AR in primary skeletal muscle myotubes and induces hypertrophy of skeletal muscle myotubes. Compared with formoterol, 5-HOB demonstrates comparable full-agonist activity on cAMP production in skeletal muscle cells and skeletal muscle tissue-derived membranes. In contrast, a greatly reduced intrinsic activity was determined in cardiomyocytes and cell membranes prepared from the rat heart. In addition, 5-HOB shows weak effects on chronotropy, inotropy, and vascular relaxation compared with formoterol. In vivo, 5-HOB significantly increases hind limb muscle weight in rats with attenuated effects on heart weight and ejection fraction, unlike formoterol. Furthermore, changes in cardiovascular parameters after bolus subcutaneous treatment in rats and rhesus monkeys are significantly lower with 5-HOB compared with formoterol. In conclusion, the pharmacological profile of 5-HOB indicates superior tissue selectivity compared with the conventional ß 2-AR agonist formoterol in preclinical studies and supports the notion that such tissue-selective agonists should be investigated for the safe treatment of muscle-wasting conditions without cardiovascular limiting effects.

Optimal flip angle for robust practical quantitative NMR measurement using a fixed pulse length.

NMR quantification has been traditionally performed by using internal standards. Although methods using external reference in NMR quantification have been developed, the major obstacles in using external referencing method are the measurement deviations associated with changing sample conditions and the requirement of pulse width calibration for every sample in order to compensate these errors. The calibration process is time consuming and in some cases impossible. We developed a quantitative NMR method fixed pulse length (FIXPUL) for all measurements without sample-by-sample calibration. The method is based on the use of an optimal flip angle calibrated for an external standard so that the quantitative errors associated with the pulse width variations are minimized. FIXPUL can be implemented on most basic NMR spectrometers and is robust and easily automated. The method is applicable to a wide range of solution NMR samples in chemistry, biology, and drug research and discovery.

Incidence of diplopia after division and reattachment of the inferior oblique muscle during orbital fracture repair.

BACKGROUND: Wide surgical access to the orbital floor and medial wall is often impaired by the course of the inferior oblique muscle. There is no current consensus on the optimal surgical approach for exposure, and techniques involving inferior oblique division are generally shunned for concern of possible complications. OBJECTIVE: To determine the safety and outcomes of inferior oblique division and reattachment for surgical access to the orbital floor and medial wall during orbital fracture repair. METHODS: Retrospective, single-center, review of 85 patients that underwent orbital floor, medial wall or combined fracture repair with division and reattachment of the inferior oblique near its origin. Measured characteristics include surgical approach, type of surgery, time to surgery, pre- and post-operative diplopia, enophthalmos, and complications. RESULTS: Forty-five patients (52.9%) with no pre-operative diplopia were followed up for a mean of six months. Of these, six patients (13.3%) developed post-operative binocular diplopia that resolved in all patients on an average of three months (range 2-6 months). No patients developed torsional diplopia. One patient developed a hematoma two years later attributable to capsular contraction around the implant. CONCLUSION: Division and reattachment of the inferior oblique muscle is a safe method that allows for panoramic surgical visualization of the inferior and medial orbit.

Advancing RF pulse design using an open-competition format: Report from the 2015 ISMRM challenge.

PURPOSE: To advance the best solutions to two important RF pulse design problems with an open head-to-head competition. METHODS: Two sub-challenges were formulated in which contestants competed to design the shortest simultaneous multislice (SMS) refocusing pulses and slice-selective parallel transmission (pTx) excitation pulses, subject to realistic hardware and safety constraints. Short refocusing pulses are needed for spin echo SMS imaging at high multiband factors, and short slice-selective pTx pulses are needed for multislice imaging in ultra-high field MRI. Each sub-challenge comprised two phases, in which the first phase posed problems with a low barrier of entry, and the second phase encouraged solutions that performed well in general. The Challenge ran from October 2015 to May 2016. RESULTS: The pTx Challenge winners developed a spokes pulse design method that combined variable-rate selective excitation with an efficient method to enforce SAR constraints, which achieved 10.6 times shorter pulse durations than conventional approaches. The SMS Challenge winners developed a time-optimal control multiband pulse design algorithm that achieved 5.1 times shorter pulse durations than conventional approaches. CONCLUSION: The Challenge led to rapid step improvements in solutions to significant problems in RF excitation for SMS imaging and ultra-high field MRI. Magn Reson Med 78:1352-1361, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

Descemet membrane detachment during cataract surgery: etiology and management.

PURPOSE OF REVIEW: The review updates the mechanisms, clinical presentations, diagnoses, and managements of Descemet membrane detachment during cataract surgery. RECENT FINDINGS: The advent of new imaging techniques such as anterior segment optical coherence tomography and better comprehension of the clinical and pathological aspects of detachment have improved the diagnosis and treatment of this complication to the extent that the first algorithms and protocols have been proposed. SUMMARY: Though infrequent, Descemet membrane detachment is a complication of intraocular surgery, including cataract surgery and phacoemulsification. Since the first systematic description and classification in the literature by Samuels in 1928 and its characterization as a potential sight-threatening condition by Scheie in 1964, plenty of retrospective and anecdotal evidence contribute to uncertainty and debate. The main controversy still lies in the choice between conservative treatment in hopes of spontaneaous reattachment and surgical treatment in a timely manner to maximize visual recovery.

Correction: A Novel Role for the TIR Domain in Association with Pathogen-Derived Elicitors.

[This corrects the article DOI: 10.1371/journal.pbio.0050068.].

Reduction of voxel bleeding in highly accelerated parallel (1) H MRSI by direct control of the spatial response function.

PURPOSE: To substantially improve spatial localization in magnetic resonance spectroscopic imaging (MRSI) accelerated by parallel imaging. This is important in order to make MRSI more reliable as a tool for clinical applications. METHODS: The sensitivity encoding acceleration technique with spatial overdiscretization is applied for the reconstruction of parallel MRSI. In addition, the spatial response function is optimized by minimizing its deviation from a previously chosen target function. This modified minimum-norm sensitivity encoding-MRSI reconstruction approach is applied in this article for in vivo pulse-acquire MRSI of human brain at 7T with simulated acceleration factors of 2, 4, and 9 as well as actual 4-fold accelerated MRSI. RESULTS: The sidelobes of the spatial response function are significantly suppressed, which reduces far-reaching voxel bleeding. At the same time, the major enlargement of the effective voxel size, which would be introduced by conventional k-space apodization methods, is largely avoided. Regularization allows for a practical trade-off between noise minimization, effective voxel size, and unaliasing. Although not aiming at increasing the nominal spatial resolution, a better spatial specificity is achieved. CONCLUSION: Simultaneous suppression of short- and far-reaching voxel bleeding in MRSI is analyzed and reconstruction of highly accelerated parallel in vivo MRSI is demonstrated.

Quantum-size-controlled photoelectrochemical fabrication of epitaxial InGaN quantum dots.

We demonstrate a new route to the precision fabrication of epitaxial semiconductor nanostructures in the sub-10 nm size regime: quantum-size-controlled photoelectrochemical (QSC-PEC) etching. We show that quantum dots (QDs) can be QSC-PEC-etched from epitaxial InGaN thin films using narrowband laser photoexcitation, and that the QD sizes (and hence bandgaps and photoluminescence wavelengths) are determined by the photoexcitation wavelength. Low-temperature photoluminescence from ensembles of such QDs have peak wavelengths that can be tunably blue shifted by 35 nm (from 440 to 405 nm) and have line widths that narrow by 3 times (from 19 to 6 nm).

Hierarchical IDEAL: fast, robust, and multiresolution separation of multiple chemical species from multiple echo times.

We describe a generalized version of hierarchical IDEAL that can flexibly handle arbitrary chemical species at arbitrary echo times. The proposed work is fast and robust, and it has three key features: (1) multiresolution approach, which allows the method to handle images with disjoint regions, makes it less susceptible to local optima, and reduces the ambiguity of the separation; (2) direct phase estimation, which bypasses the phase wrapping issue, and (3) efficient algebraic formulation, which enables fast calculation and insensitivity to spatially varying phase across the image, from sources such as partial echo acquisition, receiver coils, motion, and flow. Representative results at 1.5 T and 3 T are presented from human ankle, wrist, and a water/oil/silicone phantom.

MRI temporal acceleration techniques.

In recent years, there has been an explosive growth of magnetic resonance imaging (MRI) techniques that allow faster scan speed by exploiting temporal or spatiotemporal redundancy of the images. These techniques improve the performance of dynamic imaging significantly across multiple clinical applications, including cardiac functional examinations, perfusion imaging, blood flow assessment, contrast-enhanced angiography, functional MRI, and interventional imaging, among others. The scan acceleration permits higher spatial resolution, increased temporal resolution, shorter scan duration, or a combination of these benefits. Along with the exciting developments is a dizzying proliferation of acronyms and variations of the techniques. The present review attempts to summarize this rapidly growing topic and presents conceptual frameworks to understand these techniques in terms of their underlying mechanics and connections. Techniques from view sharing, keyhole, k-t, to compressed sensing are covered.

Preclinical evaluation of potential nilotinib cardiotoxicity.

In vitro, concentrations ≥ 10 µM of nilotinib were needed to induce markers of cytotoxicity, apoptosis, and endoplasmic reticulum stress in both neonatal rat ventricular myocytes, a putative target tissue, and non-target heart fibroblasts, indicating a lack of cardiomyocyte-specific nilotinib toxicity in vitro. In rats, oral nilotinib treatment at 80 mg/kg for 4 weeks induced increased heart weight; however, this was not associated with relevant histopathological changes or effects on heart function. Thus, nilotinib at and above clinically relevant concentrations (4.27 µM) did not induce overt cardiovascular pathologies or heart failure in vitro or in vivo under study conditions.

Ultrafast imaging: principles, pitfalls, solutions, and applications.

Ultrafast MRI refers to efficient scan techniques that use a high percentage of the scan time for data acquisition. Often, they are used to achieve short scan duration ranging from sub-second to several seconds. Alternatively, they may form basic components of longer scans that may be more robust or have higher image quality. Several important applications use ultrafast imaging, including real-time dynamic imaging, myocardial perfusion imaging, high-resolution coronary imaging, functional neuroimaging, diffusion imaging, and whole-body scanning. Over the years, echo-planar imaging (EPI) and spiral imaging have been the main ultrafast techniques, and they will be the focus of the review. In practice, there are important challenges with these techniques, as it is easy to push imaging speed too far, resulting in images of a nondiagnostic quality. Thus, it is important to understand and balance the trade-off between speed and image quality. The purpose of this review is to describe how ultrafast imaging works, the potential pitfalls, current solutions to overcome the challenges, and the key applications.

Imatinib does not induce cardiotoxicity at clinically relevant concentrations in preclinical studies.

Cytotoxic concentrations of imatinib mesylate (10-50 microM) were required to trigger markers of apoptosis and endoplasmic reticulum stress response in neonatal rat ventricular myocytes and fibroblasts, with no significant differences observed between c-Abl silenced and nonsilenced cells. In mice, oral or intraperitoneal imatinib treatment did not induce cardiovascular pathology or heart failure. In rats, high doses of oral imatinib did result in some cardiac hypertrophy. Multi-organ toxicities may have increased the cardiac workload and contributed to the cardiac hypertrophy observed in rats only. These data suggest that imatinib is not cardiotoxic at clinically relevant concentrations (5 microM).

Discovery of NVP-LDE225, a Potent and Selective Smoothened Antagonist.

The blockade of aberrant hedgehog (Hh) signaling has shown promise for therapeutic intervention in cancer. A cell-based phenotypic high-throughput screen was performed, and the lead structure (1) was identified as an inhibitor of the Hh pathway via antagonism of the Smoothened receptor (Smo). Structure-activity relationship studies led to the discovery of a potent and specific Smoothened antagonist N-(6-((2S,6R)-2,6-dimethylmorpholino)pyridin-3-yl)-2-methyl-4'-(trifluoromethoxy)biphenyl-3-carboxamide (5m, NVP-LDE225), which is currently in clinical development.

Something old, something new: plant innate immunity and autophagy.

Autophagy performs a variety of established functions during plant growth and development. Recently, autophagy has been further implicated in the regulation of programmed cell death induced during the plant innate immune response. In this chapter we describe specific mechanisms through which autophagy may contribute to a successful defense against pathogen invasion. Accumulating evidence shows that the plant immune system utilizes the chloroplasts as primary sites for the regulation of cell death programs. Viruses also appear to utilize the chloroplast as a site of replication and accumulation, potentially inactivating chloroplast defense signaling in the process. Autophagy-like mechanisms have been observed to target the chloroplast, which we refer to as "chlorophagy," potentially targeting invasive viruses for degradation or regulating chloroplast-based signaling during the immune response. We hypothesize that chlorophagy is significant for the execution of plant immune defenses, during both basal and effector-triggered immunity.

Autophagy and plant innate immunity: Defense through degradation.

Autophagy is a process of bulk degradation and nutrient sequestration that occurs in all eukaryotes. In plants, autophagy is activated during development, environmental stress, starvation, and senescence. Recent evidence suggests that autophagy is also necessary for the proper regulation of hypersensitive response programmed cell death (HR-PCD) during the plant innate immune response. We review autophagy in plants with emphasis on the role of autophagy during innate immunity. We hypothesize a role for autophagy in the degradation of pro-death signals during HR-PCD, with specific focus on reactive oxygen species and their sources. We propose that the plant chloroplasts are an important source of pro-death signals during HR-PCD, and that the chloroplast itself may be targeted for autophagosomal degradation by a process called chlorophagy.

Assessment of left ventricular volumes and mass with fast 3D cine steady-state free precession k-t space broad-use linear acquisition speed-up technique (k-t BLAST).

PURPOSE: To compare left ventricular (LV) volume and mass assessment using two-dimensional (2D) cine steady-state free precession (SSFP) and k-t space broad-use linear acquisition speed-up technique (k-t BLAST) accelerated 3D magnetic resonance imaging (MRI). MATERIALS AND METHODS: On a commercially available 1.5T MR scanner, 2D cine SSFP, six- and eight-fold accelerated 3D k-t BLAST were performed to evaluate LV volumes and mass in 17 volunteers. After semiautomatic segmentation of the different MR data sets, the resulting volumes and mass were compared according to the mean difference, 95% confidence interval, standard deviation (SD), Pearson's correlation coefficient, Bland-Altman analysis, and the Pitman-Morgan test. RESULTS: Data acquisition was successful in all subjects. The number of required breathholds was reduced from a maximal of five for the 2D cine SSFP sequence to two for 3D k-t BLAST sequences. Comparing LV volumes, there was excellent agreement between 2D and 3D cine 8x k-t BLAST SSFP volumes (mean difference +/- 2SD end-diastolic volume [EDV] = 5 +/- 8 mL, end-systolic volume [ESV] = 1 +/-12 mL, and stroke volume [SV] = 3 +/- 8 mL), and mass (-1.8 +/- 9 g). CONCLUSION: k-t BLAST-accelerated 3D sequences allow accurate assessment of LV volumes and mass compared to 2D cine SSFP. This method may reduce costs and increase patient comfort due to shortened data acquisition time and reduced number of breathholds.

Determination of peak velocity in stenotic areas: echocardiography versus k-t SENSE accelerated MR Fourier velocity encoding.

The study was approved by the local ethical committees, and informed consent from each participant was obtained. The purpose of the study was to compare accelerated magnetic resonance (MR) Fourier velocity encoding (FVE), MR phase-contrast velocity mapping, and echocardiography with respect to peak velocity determination in vascular or valvular stenoses. FVE data collection was accelerated by using the k-space and time sensitivity encoding, or k-t SENSE, technique. Peak velocities were evaluated in five healthy volunteers (one woman, four men; mean age, 28 years; range, 23-34 years), three patients with stenotic aortic valves (two women, one man; mean age, 67 years; range, 39-82 years), two patients with pulmonary valvular stenosis (a 14-year-old girl and a 36-year-old man), and two patients with aortic stenosis (two women aged 18 and 27 years). In volunteers, peak velocity determined by the different methods agreed well. In patients, similar peak velocities were obtained by using accelerated MR FVE and echocardiography, while phase-contrast MR imaging results tended to underestimate these values.

A novel role for the TIR domain in association with pathogen-derived elicitors.

Plant innate immunity is mediated by Resistance (R) proteins, which bear a striking resemblance to animal molecules of similar function. Tobacco N is a TIR-NB-LRR R gene that confers resistance to Tobacco mosaic virus, specifically the p50 helicase domain. An intriguing question is how plant R proteins recognize the presence of pathogen-derived Avirulence (Avr) elicitor proteins. We have used biochemical cell fraction and immunoprecipitation in addition to confocal fluorescence microscopy of living tissue to examine the association between N and p50. Surprisingly, both N and p50 are cytoplasmic and nuclear proteins, and N's nuclear localization is required for its function. We also demonstrate an in planta association between N and p50. Further, we show that N's TIR domain is critical for this association, and indeed, it alone can associate with p50. Our results differ from current models for plant innate immunity that propose detection is mediated solely through the LRR domains of these molecules. The data we present support an intricate process of pathogen elicitor recognition by R proteins involving multiple subcellular compartments and the formation of multiple protein complexes.