Citations

Background Remote limb ischemic postconditioning (RLIPoC) has been demonstrated to protect against ischemic stroke. However, the underlying mechanisms of RLIPoC mediating cross‐organ protection remain to be fully elucidated. Methods and Results Ischemic stroke was induced by middle cerebral artery occlusion for 60 minutes. RLIPoC was performed with 3 cycles of 10‐minute ischemia followed by 10‐minute reperfusion of the bilateral femoral arteries immediately after middle cerebral artery reperfusion. The percentage of regulatory T cells (Tregs) in the spleen, blood, and brain was detected using flow cytometry, and the number of Tregs in the ischemic hemisphere was counted using transgenic mice with an enhanced green fluorescent protein‐tagged Foxp3. Furthermore, the metabolic status was monitored dynamically using a multispectral optical imaging system. The Tregs were conditionally depleted in the depletion of Treg transgenic mice after the injection of the diphtheria toxin. The inflammatory response and neuronal apoptosis were investigated using immunofluorescent staining. Infarct volume and neurological deficits were evaluated using magnetic resonance imaging and the modified neurological severity score, respectively. The results showed that RLIPoC substantially reduced infarct volume, improved neurological function, and significantly increased Tregs in the spleen, blood, and ischemic hemisphere after middle cerebral artery occlusion. RLIPoC was followed by subsequent alteration in metabolites, such as flavin adenine dinucleotide and nicotinamide adenine dinucleotide hydrate, both in RLIPoC‐conducted local tissues and circulating blood. Furthermore, nicotinamide adenine dinucleotide hydrate can mimic RLIPoC in increasing Tregs. Conversely, the depletion of Tregs using depletion of Treg mice compromised the neuroprotective effects conferred by RLIPoC. Conclusions RLIPoC protects against ischemic brain injury, at least in part by activating and maintaining the Tregs through the nicotinamide adenine dinucleotide/nicotinamide adenine dinucleotide hydrate pathway.

HYLS1 regulates the ciliary phosphoinositide and hedgehog pathways, implicating a novel pathogenic mechanism for HLS syndrome.

Ischemic stroke results from thrombus becoming lodged in a vessel in the cerebrovascular circulation. The constituents of the thrombus can vary widely and have direct effects on the mechanical properties of the thrombus. Thrombectomy procedures could potentially be improved if the mechanical properties of the thrombus could be determined prior to treatment. In the study, we developed a new non-contact method associated with Rayleigh wave propagations for evaluating mechanical properties of human clotted blood, referred to as ultrasound-mediated optical coherence elastography (UOCE). Due to clot mechanical properties being associated with fibrin and platelet content, eight different clot analogues with varying fibrin/platelets concentrations, from 0.6% (control group) to 19.0%, were produced, and the clot analog in each concentration was repeatedly measured five times. A highly focused transducer with a center frequency of 7.5 MHz was used to generate acoustic radiation forces exerted on the surface of clotted blood to induce Rayleigh wave propagations. The transducer was driven by a 50 dB radio frequency amplifier a 4 ms pulse which was repeated at a rate of 19 Hz. The optical coherence tomography (OCT) acquisition was set to 50 lateral positions and 4000 A-scans for each lateral position at a 76 kHz scan rate for total acquisition time of 52.6 ms. The results demonstrated that the Rayleigh wave group velocities positively correlated with the concentrations of fibrin/platelets. The group velocities ranged from 0.78 ± 0.02 m/s for 0.6% fibrin/platelets and increased to 2.42 ± 0.06 m/s at a fibrin/platelets concentration of 19.0%. There are statistically significant difference ( p <0.05) between control group and all clot analogues with a fibrin/platelets concentration of greater than 2.3%. In conclusion, we propose UOCE as a novel approach capable of evaluating mechanical properties of human blood clots based on Rayleigh wave propagation. This sensitive method can be used for the evaluation of the mechanical properties of human blood clot analogues and thrombectomy samples.

The circadian rhythm is an internal clock responsible for a variety of physiological processes occurring within a 24‐hour cycle. Synchronized by a master clock in the brain, the circadian rhythm consists of a transcriptional‐translational feedback loop (TTFL) capable of inducing oscillating gene expression in all the cells throughout the organism. The TTFL begins with the heterodimerization of two transcription factors, BMAL1 and CLOCK, resulting in the transcription and translation of many circadian‐related genes. The target protein of interest, human neuronal PAS domain protein 2 (hNPAS2) is a paralog of CLOCK that can serve as a positive regulator of the circadian rhythm by heterodimerizing with BMAL1. Previous research suggests that disruption in the expression of hNPAS2 may result in improper circadian functioning and development of sleeping and mental disorders. In this study, the full‐length eukaryotic form of hNPAS2 was cloned into a bacterial expression vector. However, bacterial expression has led to misfolding and aggregation of the recombinant hNPAS2, becoming the central issue of the study. In an effort to obtain soluble and homogeneous hNPAS2, multiple expression and purification methods have been developed. The resultant purified soluble protein will enable future structural and functional studies, which can bring new insights to the regulatory mechanisms of the circadian rhythm and understanding of circadian‐related disorders. Additionally, a portion of this research was integrated into a teaching module delivered by the leading student researcher to a senior undergraduate advanced biochemistry course. Multiple novel pedagogic techniques were employed in the teaching module with the objective of raising the students' interests to research as well as their abilities to apply the principles and concepts of biochemistry learned in the course in a real scientific study. Support or Funding Information Research reported in this poster was supported by the National Institute of General medical Sciences of the National Institutes of Health under linked Award Numbers RL5GM118969, TL4GM118971, AND UL1GM118970. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health Research reported in this poster was supported by the National Research of General Medical Sciences of NIH under award number SC3GM109870 Research reported in this poster was supported has used core facility at BBRC supported by National Institute of Minority Health and Health Disparities under award number 5G12MD007592 This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .

Background There is heterogeneity in the names and anatomical descriptions of regional anesthetic techniques. This may have adverse consequences on education, research, and implementation into clinical practice. We aimed to produce standardized nomenclature for abdominal wall, paraspinal, and chest wall regional anesthetic techniques. Methods We conducted an international consensus study involving experts using a three-round Delphi method to produce a list of names and corresponding descriptions of anatomical targets. After long-list formulation by a Steering Committee, the first and second rounds involved anonymous electronic voting and commenting, with the third round involving a virtual round table discussion aiming to achieve consensus on items that had yet to achieve it. Novel names were presented where required for anatomical clarity and harmonization. Strong consensus was defined as ≥75% agreement and weak consensus as 50% to 74% agreement. Results Sixty expert Collaborators participated in this study. After three rounds and clarification, harmonization, and introduction of novel nomenclature, strong consensus was achieved for the names of 16 block names and weak consensus for four names. For anatomical descriptions, strong consensus was achieved for 19 blocks and weak consensus was achieved for one approach. Several areas requiring further research were identified. Conclusions Harmonization and standardization of nomenclature may improve education, research, and ultimately patient care. We present the first international consensus on nomenclature and anatomical descriptions of blocks of the abdominal wall, chest wall, and paraspinal blocks. We recommend using the consensus results in academic and clinical practice.

We report a technique, named optical coherence viscometry (OCV), to measure the viscosity of Newtonian fluids in a noncontact manner. According to linear wave theory with small amplitudes, capillary waves are associated with fluid mechanical properties. To perform this measurement and avoid the overdamped effects of capillary waves in viscous fluids, transient acoustic radiation force was applied to generate capillary waves. Within a very limited field-of-view using optical coherence tomography, wave motion acquired in the time domain was analyzed using Fourier methods to study the wave velocity dispersion and attenuation relationships for capillary waves, which can reduce the fluid quantity drastically into tissue culture scale. We measure the viscosities of water, water–glycerol solutions with three concentrations, and biological plasma using the proposed OCV and compare the experimental results to theoretical calculations. OCV is sensitive to wave perturbations and can be a promising technique for measuring the viscosity of biological fluids and could be applied in future applications for measurements for lipid membranes in cell biology and tissue engineering investigation.

Mechanical properties in tissues are an important indicator because they are associated with disease states. One of the well-known excitation sources in optical coherence elastography (OCE) to determine mechanical properties is acoustic radiation force (ARF); however, a complicated focusing alignment cannot be avoided. Another excitation source is a piezoelectric (PZT) stack to obtain strain images via compression, which can affect the intrinsic mechanical properties of tissues in tissue engineering. In this study, we report a new technique called two-dimensional (2D) dynamic vibration OCE (DV-OCE) to evaluate 2D wave velocities without tedious focusing alignment procedures and is a non-contact method with respect to the samples. The three-dimensional (3D) Fourier transform was utilized to transfer the traveling waves (x, y, t) into 3D k-space (kx, ky, f). A spatial 2D wavenumber filter and multi-angle directional filter were employed to decompose the waves with omni-directional components into four individual traveling directions. The 2D local wave velocity algorithm was used to calculate a 2D wave velocity map. Six materials, two homogeneous phantoms with 10 mm thickness, two homogeneous phantoms with 2 mm thickness, one heterogeneous phantom with 2 mm diameter inclusion and an ex vivo porcine kidney, were examined in this study. In addition, the ARF-OCE was used to evaluate wave velocities for comparison. Numerical simulations were performed to validate the proposed 2D dynamic vibration OCE technique. We demonstrate that the experimental results were in a good agreement with the results from ARF-OCE (transient OCE) and numerical simulations. Our proposed 2D dynamic vibration OCE could potentially pave the way for mechanical evaluation in tissue engineering and for laboratory translation with easy-to-setup and contactless advantages.

AbstractEmbolectomy is one of the emergency procedures performed to remove emboli. Assessing the composition of human blood clots is an important diagnostic factor and could provide guidance for an appropriate treatment strategy for interventional physicians. Immunostaining has been used to identity compositions of clots as a gold‐standard procedure, but it is time‐consuming and cannot be performed in situ. Here, we proposed that the optical attenuation coefficient of optical coherence tomography (OCT) can be a reliable indicator as a new imaging modality to differentiate clot compositions. Fifteen human blood clots with multiple red blood cell (RBC) compositions from 21% to 95% were prepared using healthy human whole blood. A homogeneous gelatin phantom experiment and numerical simulation based on the Lambert–Beer's law were examined to verify the validity of the attenuation coefficient estimation. The results displayed that optical attenuation coefficients were strongly correlated with RBC compositions. We reported that attenuation coefficients could be a promising biomarker to guide the choice of an appropriate interventional device in a clinical setting and assist in characterizing blood clots.