Blue Arrow Research Articles

Silicon alleviates the toxicity of microplastics on kale by regulating hormones, phytochemicals, ascorbate-glutathione cycling, and photosynthesis

Kale is rich in various essential trace elements and phytochemicals, including glucosinolate and its hydrolyzed product isothiocyanate, which have significant anticancer properties. Nowadays, new types of pollutant microplastics (MP) pose a threat to global ecosystems due to their high bioaccumulation and persistent degradation. Silicon (Si) is commonly used to alleviate abiotic stresses, offering a promising approach to ensure safe food production. However, the mechanisms through which Si mitigates MP toxicity are unknown. In this study, a pot culture experiments was conducted to evaluate the morphogenetic, physiological, and biochemical responses of kale to Si supply under MP stress. The results showed that MP caused the production of reactive oxygen species, inhibited the growth and development of kale, and reduced the content of phytochemicals by interfering with the photosynthetic system, antioxidant defense system, and endogenous hormone regulation network. Si mitigated the adverse effects of MP by enhancing the photosynthetic capacity of kale, regulating the distribution of substances between primary and secondary metabolism, and strengthening the ascorbate-glutathione (AsA-GSH) cycling system. SummaryEffects of microplastic and silicon on key indicators of kale. Note: The red arrows and blue arrows indicate the MP treatment effect compared to the control and Si treatment effect compared to the MP treatment, respectively.

КАЛЛУСООБРАЗОВАНИЕ КАК ФИЗИОЛОГИЧЕСКИЙ ПРИЗНАК НЕДОСТАТКА АУКСИНА В СОСТАВЕ СТИМУЛЯТОРА РИЗОГЕНЕЗА (НА ПРИМЕРЕ УКОРЕНЕНИЯ IN VIVО ЧЕРЕНКОВ ХВОЙНЫХ КУЛЬТУР)

Characteristics of the effectiveness of rooting of coniferous crops are the percentage of rooting, the number of roots formed and their length. Callus formation often accompanies the rooting process, but research data on the relationship of this process with the effectiveness of rooting is contradictory. In the conditions of film cuttings equipped with heated substrate, studies were carried out on the relationship between the rooting of cuttings of coniferous crops and callus formation. To stimulate the rooting of semi-lignified cuttings of Juniperus scopulorum S. cultivar Skyrocket, growth powders Chrysatop and Rizapon 1% containing indolyl-3-butyric acid (IBA) in different concentrations were used. In the control treatment without a stimulant, all cuttings formed callus without rooting; when the bases of the cuttings were dusted with Chrysatop containing 0.25% IBA, callus formation decreased by 3.8 times, and the survival rate was 76%. In the variant with Rizapon powder containing 1% IMC, no callus formation was observed at all, the survival rate reached 81.4%. To stimulate the rooting of green cuttings of Juniperus scopulorum S. variety Blue Arrow, aqueous solutions of potassium salt IMC (IMC-K) were used in the concentration range from 0 to 150 mg/l when the bases of the cuttings were soaked for 16 hours. In the concentration range from 0 to 100 mg/l, an increase in survival rate by 1.89 and 3.87 times was observed, respectively, callus formation decreased by 3.38 times. To stimulate the rooting of semi-lignified cuttings of Thuja occidentalis L. variety Smaragd, Juníperus sabina L. species form and green cuttings of Thuja occidentalis L. variety Brabant, Kornevin growth powder containing 0.5% IBA was used. To obtain a concentration gradient, the powder was diluted with talc. Against the background of high survival rate of cuttings of Thuja occidentalis L. of both varieties – 82.85–96.9%, callus formation decreased from 92.9% in the control variant to 6.3% in the variant with pure Kornevin in cuttings of the Smaragd variety and from 71.88% in the control variant to 19.1% in variant Kornevin:talc 1:1 in cuttings of the Brabant variety. When rooting cuttings of Juniperus sabina L. with an increase in the concentration of IBA in the powder from 0 to 0.25% IBA, the survival rate increased from 10.71 to 89.29%, and the formation of callus on the cuttings decreased from 44.59 to 0%. The data obtained indicate that calus formation can serve as a sign of a lack of exogenous auxin in the rooting stimulator and, accordingly, an increase in the auxin content, all other things being equal, within the effective range is one of the ways to increase the percentage of survival of cuttings of coniferous crops.

Classic Hodgkin Lymphomas Display Neuronal-Glial Lineage Transdifferentiation

The molecular drivers of classic Hodgkin lymphoma (HL) underlying its pathologic and clinical distinctions from non-Hodgkin lymphoma (NHL) have been challenging to uncover. The study of HL has been impeded by the rarity of the Hodgkin-Reed-Sternberg (HRS) cells within a dense tumor microenvironment (TME). Previously, we developed a FACS approach to isolate the HRS cells and profiled their whole exomes and genomes (Reichel et al 2015; Maura et al 2023). These studies did not reveal an HRS-specific mutational signature, but rather mutations that overlap with those of NHL, such as those in SOCS1 and HIST1H1E. These data suggested that non-genetic factors such as the underlying cell state may cooperate with somatic mutations to induce HL. However, we previously lacked the ability to co-map somatic mutations and cell states within the same cancer cells. We thus developed Genotyping of Transcriptomes (GoT; Nam et al 2019) that links single-cell RNA-seq (scRNA-seq) and somatic mutations within the same thousands of individual cells. We applied GoT to primary HL samples (n = 10 HL; 68291 cells, Fig. 1A) after FACS-isolation of HRS cells. We analytically integrated the cells across the samples based on gene expression and identified the expected cell types including B-cells, T-cells, monocytes and HRS cells (Fig. 1B). As expected, the HRS cells displayed low expression of B-cell antigens ( CD19, CD79A) and high levels of TNFRSF8 (CD30), CCL17, CCR7 and PD-L1 (Fig. 1C). GoT data revealed that mutations were restricted to the HRS cells (Fig. 1D). Copy number variation (CNV) analysis further confirmed that CNVs were specific to the HRS cells (Fig. 1E). As scRNA-seq has unveiled marked intratumoral cell state heterogeneity across cancers, we posited that the HRS cells may display heterogeneous cell states. Indeed, we identified distinct cell states (Fig. 1F), including cycling HRS and metabolically-active HRS cells upregulating the translation machinery ( NACA, RACK1). We also observed a cell state with elevated inflammatory signals ( TNF, JUN, FOS, CCL22). One group demonstrated a partially preserved B cell program with high CD19 and CD79A. Unexpectedly, we also identified an HRS state with features of neuronal-glial (NG) transdifferentiation, including genes involved in synapse formation ( NRG2, NRXN3). Consistently, genes upregulated in the NG state were enriched in nervous system and neuronal development pathways (Fig. 1G). We further assessed NG gene expressions across normal cell types and confirmed their specificity to NG lineage cells (Fig. 1H). These findings were consistent with dendritic processes of HRS cells highlighted by CD15 and CD30 (Fig. 1I, red arrows). Areas of CD15/CD30 staining devoid of nucleus (Fig. 1I, blue arrows) corroborated the presence of dendritic processes. These results suggested that the NG differentiation may be a key defining feature of HRS cells, whereby dendritic processes facilitate a tight control of the TME. Consistently, we identified strong HRS-immune complexes that persisted through tissue processing and sorting (Fig. 1F). To determine the degree of plasticity or heritability of the HRS cell states, we integrated VDJ sequencing with GoT (GoT-VDJ), whereby somatic hypermutations in the VDJ served as endogenous barcodes. Phylogenetic reconstructions revealed that HRS cell states were distributed across clades (Fig. 1J), unveiling a plastic interchange of HRS cell states. Consistently, GoT showed that mutant cells were present across the cell states (Fig. 1K), indicating that the cell states were decoupled from the genetic identities. We therefore postulated that the NG program may be encoded epigenetically. We performed single nuclei ATAC-seq on HRS-enriched HL samples (n = 5 samples; Fig. 1L). Compared to admixed B cells, the HRS cells displayed enhanced accessibility for binding motifs of the NG lineage transcription factors (TF), e.g. OLIG1/2 and SOX family (Fig. 1M), revealing the TF networks that govern the lineage infidelity program. We further identified that the NG program is cell intrinsic and at least partially stable through in vitro passaging, as 4 of 5 HL cell lines exhibited the highest NG gene expression compared to NHL cell lines (Fig. 1N). Altogether, these single-cell multi-omics studies indicated that an epigenetically encoded NG program may cooperate with lymphoma driving mutations to drive the development of HL, paving novel avenues of therapy.

Circular permutation at azurin's active site slows down its folding.

Circular permutation (CP) is a technique by which the primary sequence of a protein is rearranged to create new termini. The connectivity of the protein is altered but the overall protein structure generally remains unperturbed. Understanding the effect of CP can help design robust proteins for numerous applications such as in genetic engineering, optoelectronics, and improving catalytic activity. Studies on different protein topologies showed that CP usually affects protein stability as well as unfolding rates. Though a significant number of proteins contain metals or other cofactors, reports of metalloprotein CPs are rare. Thus, we chose a bacterial metalloprotein, azurin, and its CP within the metal-binding site (cpF114). We studied the stabilities, folding, and unfolding rates of apo- and Zn2+-bound CP azurin using fluorescence and circular dichroism. The introduced CP had destabilizing effects on the protein. Also, the folding of the Zn2+-CP protein was much slower than that of the Zn2+-WT or apo-protein. We compared this study to our previously reported azurin-cpN42, where we hadobserved an equilibrium and kinetic intermediate. cpF114 exhibits an apparent two-state equilibrium unfolding but has an off-pathway kinetic intermediate. Our study hinted at CP as a method to modify the energy landscape of proteins to alter their folding pathways. WT azurin, being a faster folder, may have evolved to optimize the folding rate of metal-bound protein compared to its CPs, albeit all of them have the same structure and function. Our study underscores that protein sequence and protein termini positions are crucial for metalloproteins. TOC Figure. (Top) Zn2+-azurin WT structure (PDB code: 1E67) and 2-D topology diagram of Zn2+-cpF114 azurin. (Bottom) Cartoon diagram representing folding (red arrows) and unfolding (blue arrows) of apo- and Zn2+- WT and cpF114 azurins. The width of the arrows represents the rate of the corresponding processes.

Abstract 111: Woven Endo Bridge‐Coil Embolization of a Middle Cerebral Artery Bifurcation Aneurysm with Secondary Lobule

Introduction 18‐36% of all intracranial aneurysms are middle cerebral artery(MCA) bifurcation aneurysms. While some are much higher risk than others, they have an overall low estimated annual rupture rate of 0.36%.(1) MCA bifurcation aneurysms have been historically challenging to treat endovascularly given they often have complex morphology and wide necks. The Woven EndoBridge (WEB) is an ellipsoid embolization device designed to provide intrasaccular flow disruption along the aneurysm neck, which has been proven to be an effective method in treating a wide spectrum of wide‐necked bifurcation aneurysms. Thromboembolism and recanalization are the main concerns in treatment with the WEB device, like any aneurysm treatment approach .(2),(3) Occasionally, irregularities and secondary lobules at the base of the primary aneurysm can have persistent filling despite treatment. Methods We present a case of a right MCA bifurcation aneurysm treated by a WEB device and coil embolization. Results 48‐year‐old female with a medical history significant only for active smoking who presented with sudden onset of the worst headache of her life followed by brief loss of consciousness. No neurological evaluation was sought initially, until 2 weeks later as she continued to experience a moderate‐intensity headache associated with nausea and vomiting with frequent falls. On exam, she was alert and oriented, moving all extremities with full strength. CT head revealed an evolving acute to subacute right MCA infarction with adjacent small volume subarachnoid hemorrhage. CTA head revealed a right MCA bifurcation aneurysm measuring 6 x 6 x 7 mm with irregularity of the wall. Multifocal severe stenosis was noted in the right distal right M1 and right M2 divisions. She underwent a diagnostic subtraction angiography which confirmed an irregular right MCA bifurcation aneurysm measuring 4.3 x 4.5 x 5.7 mm (Figure 1 ‐A,B). While it was believed that the subarachnoid hemorrhage was more likely related to the recent infarct, a decision was made to treat the aneurysm given its relatively large size and irregular shape. Embolization was performed with a WEB SL 6 x 4 mm device (Figure 1: C,D ‐blue arrow). Post‐deployment angiograph showed occlusion of the aneurysm dome but persistent filling of the secondary lobule near the base of the aneurysm. Given this residual lobule filling, a decision was made to continue additional embolization with a hyper soft 3D 2 mm X 2 cm coil(Figure 1: C,D ‐ yellow arrow). Final angiography revealed complete occlusion of the aneurysm. Vasospasm of the distal M2 divisions and multiple M3 branches in the right MCA vascular territory was also noted. Therefore, she was treated with 20 mg of intra‐arterial Verapamil with improvement. She was started on Aspirin 325 mg daily. Daily transcranial dopplers were negative for vasospasm. She remained neurologically stable and was discharged home 5 days after admission ambulating independently. Conclusion With modern advances in endovascular devices, many MCA bifurcation aneurysms can be treated minimally invasively. However, there are some limitations to the WEB since every aneurysm is different and there are a finite number of sizes and shapes available for WEB. This case illustrates that adjunctive coil embolization can successfully occlude a residual secondary base lobule after WEB embolization.

Toward the Development of an Electromechanical Ion-Specific Conveyer Belt

Bromide (Br−) is ubiquitous both in natural waters and those impacted by anthropogenic activities, such as, the discharge of treated or untreated wastewaters, releases from coal-fired power plants and hydraulic fracturing operations, and sea water intrusion. The development of methods for the extraction and purification of Br−, particularly from Br− -rich brines, is regarded as of great economic interest owed to the uses of bromine in many industrial processes. In fact, the removal of Br- from drinking water is beneficial from a public health perspective, as it can lead to the formation of regulated disinfection byproducts (DBPs) during water treatment. Although various alternatives have recently been proposed to remove halide anions, such as bromide, from drinking water, none of them have proven sufficiently effective for large-scale application (see e.g. Ref. 1).The present contribution describes a strategy for the removal and purification of bromide from an aqueous solution containing chloride in amounts that closely mimic those found in natural brine sources. As will be described, this tactic relies on the selective electrosorption of Br− on Au, an inert metal electrode material from such a synthetic brine, and its subsequent desorption into a second aqueous solution devoid of Br−.The all glass multi compartment cell employed for these experiments ‘shown schematically in the figure above consists of a central cylindrical cup filled with 0.01 HClO4 supporting electrolyte, which houses the reference, RE, and counter electrodes connected on either side to two identical cups of smaller diameter, C1 and C2 are separated from the central cup by glass frits so that diffusion between C1 and C2 is negligible. At the start of a regular experiment, C1 is filled with a solution containing 28 mM KCl and 12.5 mM KBr, the synthetic brine, in the supporting electrolyte, and C2 is filled with only supporting electrolyte. In the initial stage of this protocol, a gold foil is immersed in C1, which together with the RE and CE would form a conventional 3-electrode cell and a potential of 1.3 V vs RHE is then applied to the Au foil using a potentiostat to induce anion adsorption for ca.10 s. which is sufficient for Br-(aq) and Cl-(aq) to achieve their equilibrium coverages under the specific conditions of the experiment, as represented by the blue arrow. Based on the results of independent optical measurements, Br-(aq) would be the predominant ion adsorbed on the Au surface at this high potential. Subsequently, the Au foil is emersed from the solution without disconnecting the potentiostat, immersed into C2, and a potential of 0.2 V applied, which is just positive of the onset of hydrogen evolution but negative enough for adsorbed Br- to fully desorb, as represented by the red arrow. This process is then repeated tens of times, at the end of which the composition of the solution in C2 is analyzed using the methylene blue (MB) spectroscopic method described by Uraisin, et al. (2) to determine specifically Br-(aq), and a slightly modified Mohr’s turbidimetry technique, which employs K2CrO4 as the indicator, to determine the total amount of Br-(aq) and Cl-(aq).Four independent runs involving 50 to 75 sequential transfers were performed in order to assess the efficiency of this process, and found to yield an increase in the Br-(aq) concentration from an initial 30% in C1, up to higher than 75% in C2. Overall, the efficiency of this process can be increased by a corresponding increase in the area of the electrode. Alternatively, one can envision a continuous process involving a segmented electrode in the form of a belt and appropriate potential controls, that would be continuously emersed and immersed into C1 and C2, acting as a virtual ionic conveyer. Various aspects of this unique technology and its prospects for large scale implementation will be discussed. Acknowledgements This work was supported by a grant from NSF, CHE-1412060 References Sanchez-Polo, J. Rivera-Utrilla, E. Sahli, U. von Gunten, Ag-Doped Carbon Aerogels For Removing Halide Ions In Water Treatment, Water Res., 41, 2007,1031-1037Uraisin, T. Takayanagi, M. Oshima, D. Nacapricha, S. Motomizu, Kinetic-Spectrophotometric Method For The Determination Of Trace Amounts Of Bromide In Seawater, Talanta, 68, 2006, 951-956 Figure 1

P44: Toward 3D-Printed Microfluidic Artificial Lungs with Complex, Biomimetic Geometries

Purpose: Current hollow-fiber oxygenators used in Extracorporeal Membrane Oxygenation have suboptimal gas exchange performance and hemocompatibility. Microfluidic artificial lungs (µALs) promise smaller feature sizes, improving gas exchange efficiency, and biomimetic flow paths, improving blood compatibility. For the first time, we leverage the geometric freedom of 3D-printing technology to demonstrate µALs with truly 3D, biomimetic branching capillaries and gas-side designs to increase gas exchange surface area. Methods: Two µAL designs were generated in Solidworks and printed on an Asiga MAX X27 UV printer. The first was a “simple branching” µAL (Fig 1A) with quadfurcating, biomimetic branching for blood distribution. The second was a “hatched” µAL (Fig 1B) employing a gas phase with strategically placed supports to maximize gas exchange surface area while maintaining structural stability. These changes are only to the gas, and so the blood-phase is unchanged. Dyed water was used to visualize internal structures (Fig 1D). Geometric analysis and proven models were used to calculate theoretical shear rate and rated flow. Computational Fluid Dynamics (CFD) was used to visualize flow (Fig 1E,F). Experimental pressure drop vs water flow rates were measured (Fig 2). Results: Through geometric analysis (Table 1), branching distribution technique provides more uniform shear stress (0.95-1.34 dyn/cm2) compared to a non-branching “open-plenum” control (0.09-1.27 dyn/cm2). The hatched µAL has a 3.18 mL/min rated flow, 1.7x greater than the 1.84 mL/min rated flow of the non-hatched branching µAL. As a result of the higher rated flow, it also has higher theoretical shear of 1.64-2.31 dyn/cm2 (at rated flow) despite identical blood-side geometry. The branching lung demonstrated a pressure drop up to 12 mmHg at flows up to 5 mL/min (Fig 2). These are significantly larger than analytically predicted values (extrapolated 7 mmHg vs 0.233 mmHg at 3.2 mL/min), prompting investigation into resolution of internal capillaries and effects of surface roughness on pressure drop. Conclusion: We have demonstrated the first 3D-printed branching biomimetic µAL formed from a gas permeable material, with gas-side geometries to improve gas exchange efficiency. These geometries are expected to translate to greater blood flows enabling creation of future animal and human-scale µALs. Table 1. Theoretical calculations. All uALs have 256 8.5mm long 216x324 µm blood and gas channels, with 54 µm-thick membranes. They differ in their effective gas exchange area, and blood distribution method, resulting in differing rated flows, shears, and pressure drops. The Branching uAL employs a branching distribution, resulting in a much tighter shear stress range. The GasHatch uAL employs both a branching distribution, and a blood-gas geometric-synchronization, with 100% rather than 58% of the gas-exchange capillary face being used for gas exchange. Values for a theoretical “control” lung (not fabricated; contains an open plenum/ non-branching distribution region) are displayed for comparison. Flow velocity and shear stresses are calculated separately for capillary and distribution areas.Figure 1. Blood flows are indicated using red arrows, and gas flows are indicated using blue arrows. (A) Design of simple (non-hatched) branched μAL. (B) Close-up of the hatched μAL capillaries and gas channels, showing how gas-side supports are only in regions not adjacent to capillaries and therefore not reducing gas exchange surface area. (C) Hatched μAL with the gas phase filled with blue dye for visualization. (D) Non-hatched branching μAL with blood phase filled with blue dye, and gas phase filled with red dye. (E) CFD visualization of flow velocities in the branching blood distribution network; (F) CFD analysis of pressure drop in the biomimetic blood distribution channels.Figure 2. Pressure drop of branching µALs (water; n=3)

CARD10: Transapical Left Ventricular Assist Device Implantation Using a Novel Accessory in Swine

Background: Conventional left ventricular assist devices (LVADs) require an anastomosis of the outflow graft to the ascending aorta. We developed and tested a LVAD accessory, which combines pump in- and transaortic outflow in a dual lumen adapter, thus, allowing LVAD implantation solely via the left ventricular apex. Methods: The LVAD accessory (Fig. A) consisted of a 3D printed titanium inflow and a 12 mm outflow stent graft. The accessory in combination with a centrifugal LVAD (HeartMate 3, HM3, Abbott, USA) was implanted in 10 adult female Landrace pigs (104 ± 13 kg). A balloon catheter (14 mm Atlas Gold PTA Dilatation Catheter, BD, USA) was introduced via the left femoral artery and placed in the left ventricle. After lower partial sternotomy, pericardiotomy and fixation ring attachment, apical coring was performed in a standard fashion on the beating heart using cardiopulmonary bypass. The balloon was exteriorized, inflated in the outflow graft and both, the accessory with the attached outflow graft, were pulled into the left ventricle and the aorta. The accessory was attached to the fixation ring. The LVAD was connected and deaired, and the balloon catheter was removed. Results: After successful LVAD implantation in all animals, echocardiography revealed no signs of aortic or mitral regurgitation. In eight animals ramp testing was performed. The HM3 flow estimate increased from 3.7 ± 1.2 L/min at 4’500 rpm to 5.4 ± 1.2 L/min at 7’200 rpm (Fig. B). Post-mortem examination (Fig. C) revealed correct placement of the LVAD accessory with the inflow in the left ventricle (blue arrow) and the outflow graft across the aortic valve (yellow arrow). There were neither signs of damage of the aortic (*) or mitral valve (+) nor signs of thrombosis. Conclusion: The novel accessory in combination with a centrifugal LVAD allowed safe and less-invasive LVAD implantation. Ramp testing revealed effective left ventricular support in the acute swine model. Further testing in a chronic heart failure model will be performed to validate these results.

BIO27: Automated PDMS Engraving and Assembly of a Prototype Microfluidic Artificial Lung

Purpose: The ability to cost-effectively produce high-surface area microfluidic devices would bring many small-scale technologies from the realm of research to clinical and commercial applications. In particular microfluidic artificial lungs (µALs) promise improved gas exchange efficiency through micron-scale feature sizes. However, most µALs have only a single layer which limits their rated flows. Efforts to scale up these devices, such as by stacking multiple flat µALs have been labor intensive and resulted in bulky devices. Here, we present an automated roll-to-roll (R2R) manufacturing system and a cylindrical multi-layer µAL. Methods: The R2R system (Fig 1A) begins with a roll of biocompatible silicone rubber (Silpuran 2030). A heavily-modified CO2 laser engraver (Omtech K40 with custom vacuum engraving bed, N2 purge, and custom motherboard) creates patterns in the silicone sheet (Fig 1B). The sheet is then plasma-activated using two CeraPlas F-series cold-plasma wands to bond the PDMS to itself in an irreversible bond. Finally, it is rerolled into a processed device around a 30 mm PDMS core. This entire process from unrolling to rerolling is performed simultaneously and synchronously, allowing the creation of very large area microfluidic devices. Further, it is automated (Arduino Mega 1680), eliminating human error over this repetitive process. Results: Using our automated manufacturing system, we fabricated a 27-layer cylindrical prototype µAL, consisting of 1) an 8-layer base, 2) 11 layers of alternating blood and gas channels, and 3) an 8-layer protective cover. Laser-engraved fluidic channels were triangular, 60 µm deep and 180 µm wide (Fig 1B). If unrolled, the microfluidic part of this system would stretch 1.1 m, and the total length would stretch 2.7 m. This was placed into a custom 3D printed housing which routes blood and gas to their respective microfluidic channels (Fig 2A,B; filled with dyed water for visualization). Empirical pressure drop data were gathered for flows from 1 mL/min to 10 mL/min, which were similar to theoretical values (Fig 3). While the R2R manufacturing system successfully created the prototype 27-layer µAL, the device exhibited some internal fluid pooling and layer-to-layer leaks during fluidic testing. Both issues are believed to be caused by inadequate localized layer-to-layer adhesion. We plan to remedy these issues in the coming months. Conclusion: This roll-to-roll manufacturing system is designed to manufacture the first large surface-area microfluidic devices that are impractical to manufacture by conventional means. This can be employed for large-scale membrane gas exchange such as human-scale µALs.Figure 1. (A) An automated roll to roll manufacturing system for silicone. The path of the silicone is shown in green. The silicone comes on a protective PET backing, which is removed and highlighted in cyan. (B) Confocal scan of engraved Silpuran 2030. Channels were 60 µm deep, and 180 µm wide.Figure 2. (A) Finished device, with custom housing (B) Device with colored water being routed through. Red arrows depict blood connections, and blue arrows depict gas connections. Two of the blood outlets filled with blue dye, and there is a dark blue region indicating imperfect layer-to-layer bonding resulting in leaking.Figure 3. Experimental vs theoretical pressure drop across the μAL (water)

BIO12: Toward a Wearable Extracorporeal CO2 Removal System with Integrated Exhaust Gas CO2 Sensing

Purpose: Extracorporeal membrane oxygenation (ECMO) and extracorporeal carbon dioxide removal (ECCO2R) have been used frequently in the last ten years to treat patients with severe respiratory failure. These therapeutic strategies mitigate the complications associated with invasive mechanical ventilation. Further, concurrent ambulatory and physical therapy is demonstrated to improve patient outcomes, reduce hospital cost, and enhance patient quality-of-life. However, the complexity of these extracorporeal systems and rapid changes in patient metabolism and acid-base balance complicate logistics for ambulation. Here we present a wearable ECCO2R system with exhaust gas CO2 (EGCO2) sensing capabilities. Methods: The wearable ECCO2R system (Fig 1) integrates a blower module, a membrane oxygenator optimized for CO2 removal (MLung), and an exhaust module. Two redundant blowers push air through a flow sensor, to maintain fixed flow rates, then through the MLung. A CO2 sensor (STC31) in the exhaust module senses MLung EGCO2. It is preceded by a water trap, sampling pump, Nafion tubing, and heater which remove moisture and protect the STC31. Pressure sensors record the gas-side pressure drop of the MLung. First, control of sweep flow and CO2 sensing were tested individually. The blower module was attached to the MLung and commanded to maintain a set of target flows. The exhaust module was directly fed compressed CO2 and N2 to ensure it could measure a range of CO2 concentrations. Finally, as a system in-vitro test (Fig 2), the device was electronically integrated and connected to a conditioning lung fed by compressed CO2 and N2. The CO2 concentration in the sweep gas of the conditioning lung was varied to simulate metabolic changes. Results: The assembled device measures 23x20x8 cm and weighs 1.4 kg (with primed MLung and tubing; without batteries). The device quickly (<2s) attained target sweep up to 4 L/min (Fig 3A), and has a maximum sweep flow of 7 L/min with the MLung. It measured EGCO2 for all values tested (Fig 3B; up to 50 mmHg; <1 mmHg error). During the system test with water, the ECCO2R system was able to qualitatively detect changes in EGCO2 caused by the simulated metabolic changes. Conclusion: We present progress toward the first wearable ECCO2R system. Its integrated CO2 sensing makes it a suitable platform for future use as the first ECCO2R with closed-loop feedback control to automatically respond to the respiratory needs of the patient.Figure 1. (A) Blower module showing internals. (B): Sensor module; most components are enclosed. (C) Rendering of system on a patient, with arteriovenous access to the subclavian a. and v.Figure 2. System-level test setup. Blue arrows denote gas flows, and red arrows denote water flows (water is used as an analog for blood). In this test, compressed CO2 was fed into the conditioning lung. The CO2 was dissolved into the circulating water, and then removed by the MLung. Finally, it went to the exhaust module.Figure 3. (A) The device quickly attains desired sweep flows. It has a 7 L/min maximum flow rate when used with the MLung. (B) With a 2-point calibration, the device accurately (<1mmHg) measures CO2 in a gas stream, in reference to an arterial-blood-gas machine.

Walking the 'design-build-test-learn' cycle: flux analysis and genetic engineering reveal the pliability of plant central metabolism.

This article is a Commentary on Morley et al. (2023), 239: 1834–1851.

Simultaneous 3-way Paired Exchange Liver Transplantation Without Nondirected Donation: Novel Strategy to Expand the Donor Pool.

Simultaneous 3-way Paired Exchange Liver Transplantation Without Nondirected Donation: Novel Strategy to Expand the Donor Pool.

Transuterine Ultrasound-Guided Fetal Embolization of Vein of Galen Malformation, Eliminating Postnatal Pathophysiology.

Transuterine Ultrasound-Guided Fetal Embolization of Vein of Galen Malformation, Eliminating Postnatal Pathophysiology.

PO-04-087 NOT ALL THAT SHINES IS GOLD AND NOT EVERY LIGHT UP ON PET SCAN IS CARDIAC SARCOIDOSIS

Cardiac sarcoidosis (CS) and arrhythmogenic right ventricular cardiomyopathy (ARVC) are rare conditions with different pathogenesis but often similar clinical and imaging findings. Therefore differential diagnosis could be challenging. We present a case of ARVC of insidious onset mimicking CS. N/A Our patient is a 51 year-old male with no cardiac history who presented to the emergency room (ER ) with frequent chest pain. Three years ago, work up resulted in negative coronary angiogram and cardiac MRI that showed focal myocardial inflammation so he was diagnosed with myocarditis. This time, he presented to the ER with chest pain and wide complex tachycardia [figure A]. Treatment with metoprolol terminated ventricular tachycardia. Echocardiography revealed normal biventricular function with mild right ventricular (RV) enlargement. The patient underwent PET myocardial perfusion scan that showed focal FDG uptake in the basal septal and inferolateral segments suspicious for sarcoidosis [figure B,C (FDG uptake - blue arrows)]. Repeated CMR demonstrated dilated RV with regional akinesis of the free wall and late gadolinium enhancement (LGE) of RV wall [figure D,E (LGE in right venticle wall-yellow arrows)]. No LGE in the left ventricle was noted. These CMR findings were consistent with ARVC. Due to the discrepancy in the results of both imaging modalities, genetic testing was utilized for further help with the diagnosis. Results were positive for PKP2 gene mutation which is highly suggestive of ARVC. Patient continued beta-blockers and was scheduled to have a defibrillator and genetic counselling. Although CS should be considered in every ARVC like presentation, the final diagnosis should not be built on PET scan results only. Genetic testing, tissue biopsy and even repeat cardiac MRI over the course of the disease are major pillars in such critical diagnosis.

PO-05-155 A CASE OF ALCOHOL LEADING TO ISOLATION IN THE ELECTROPHYSIOLOGY LABORATORY

Ligament of Marshall alcohol ablation is a treatment for refractory atrial fibrillation and left atrial flutter. Left atrial appendage (LAA) isolation resulting from LOM ablation has not been described. To describe a case of LOM alcohol ablation which resulted in left atrial appendage isolation and dissociation of a left atrial appendage reentrant atrial flutter from the atria. A middle aged man with a history of atrial fibrillation and multiple left atrial flutters was referred for repeat ablation after multiple prior unsuccessful ablations. He previously underwent surgical MAZE and 3 endocardial ablations including an anterior mitral line and endocardial and epicardial mitral isthmus line without achieving bidirectional block. He had recurrent, symptomatic atrial flutter despite therapy with dofetilide and metoprolol. The patient presented in an atypical flutter. The ligament of Marshall was cannulated and alcohol was sequentially injected for a total of 3.8 mL. After the first alcohol injection, the tachycardia abruptly terminated on the coronary sinus (CS) catheter and sinus rhythm resumed (Figure, blue arrows), though the surface ECG showed ongoing small atrial flutter waves (Figure, red arrows). Subsequent left atrial mapping confirmed that the left atrial appendage (LAA) was isolated from the remaining left and right atrium and remained in atrial flutter (Figure C). Overdrive pacing from a multipolar catheter in the LAA demonstrated a post-pacing interval within 20 ms of the tachycardia-cycle length (Figure C). Adenosine administration resulted in AV block but no alteration in tachycardia cycle-length. These findings were highly suggestive of a reentrant mechanism. Because 3D mapping was limited by dissociated CS and LAA rhythms, manual activation mapping was performed with earliest activation at the anterior superior LAA. RF ablation at this site resulted in atrial flutter slowing and termination. In a patient with LAA flutter and prior anteroseptal and lateral linear endocardial ablation, LOM alcohol ablation may isolate the LAA. This should be recognized when counseling patients and planning procedures.

PO-02-122 TRACKING AND ABLATING THE MUSCLE SLEEVE/FASCICLE FOR PULMONARY VEIN ISOLATION

Pulmonary vein isolation (PVI) remains the cornerstone for atrial fibrillation (AF) ablation. However, it yields unsatisfactory outcomes requiring repeat procedures especially in persistent AF. Additional linear ablation, or of complex fractionated atrial electrograms, atrial rotors or ganglionated plexi prolongs procedure time and increases complications with small additional benefits. We evaluated the efficacy of a new method of tracking and ablating pulmonary vein (PV) muscle sleeve/fascicle followed by wide area circumferential ablation (WACA) as a method of treatment of AF. To track a muscle sleeve/fascicle, a Lasso catheter was placed into one PV and based on the electrograms pattern on the catheter, sites of exit of muscle sleeves/fascicles were determined along the wide area circumferential ablation (WACA) line. (Panel A of figure shows the electrogram pattern, which suggests two muscle fascicles [red and blue arrows]). Focal ablation at sites on the planned WACA line was then performed to interrupt the muscle sleeve/fascicle connection with atrium (Panel B and C of figure shows point ablation resulting in partial and complete isolation; black arrow marks the location of ablation catheter). The same method was repeated to the ipsilateral PV before full WACA of both PVs was commenced. The strategy was repeated on the contralateral PVs. Ablation of these fascicle-atrium connections resulted in PVI isolation before WACA was completed in all 18 patients. Intravenous adenosine was used at the end to elicit dormant PV connections. We schematically labeled the areas around the PVs into zones and summarized the location of these muscle fascicles in each patient. (Panel D; each dot represents a fascicle and color matches with the PV with which it is associated). Eighteen patients (61±11 years old, 56% male) with AF (12 persistent {67%}) were analyzed in this study. Fascicles were identified in all patients and focal ablation of fascicles resulted in isolation of the PVs. In addition to PVI, 8 had Cavotricuspid isthmus ablation, 1 for right focal atrial tachycardia (AT), one left focal AT, and 1 for biatrial reentrant AT. With a follow-up of 155 ±120 days, 83% of paroxysmal and 75% of persistent AF remained in sinus rhythm. Left atrial dwell time for PVI alone was less than 2 hrs and no complications were seen. The tracking and ablating muscle sleeve/fascicle before performing WACA is a strategy with outcomes superior to previously reported in literature.

Veno-Pulmonary Arterial Extracorporeal Membrane Oxygenation in Severe Acute Respiratory Distress Syndrome: Should We Consider Mechanical Support of the Pulmonary Circulation From the Outset?

Veno-Pulmonary Arterial Extracorporeal Membrane Oxygenation in Severe Acute Respiratory Distress Syndrome: Should We Consider Mechanical Support of the Pulmonary Circulation From the Outset?

A Very Rare Case of Juvenile Dermatomyositis with Typical Cutaneous Clinical Signs

A Very Rare Case of Juvenile Dermatomyositis with Typical Cutaneous Clinical Signs

A stalk with no polyp-A muco-submucosal elongated polyp in the duodenum.

A 62-year-old Caucasian man was referred for upper GI endoscopy with a 6-month history of intermittent abdominal pain, nausea and bloating. Endoscopy revealed a 5-cm elongated lesion arising in D2. A pedunculated polyp (0-Ip) was suspected; however, deeper intubation revealed no polyp at the end of the stalk (Figure 1). Narrow band imaging did not reveal any adenomatous or suspicious features (Figure 2). The base of the polyp was injected with EMR solution (gelofusin, methylene blue and adrenaline 1:100,000), resected by snare cautery (Figure 3) and the defect was closed with two endoclips. Histopathology confirmed a 42 mm × 15 mm cylindrical lesion of hyperplastic duodenal mucosa with submucosal expansion by fibroconnective tissue. Histological analysis demonstrated features of a prominent submucosal vascular component with dilated lymphovascular structures, the absence of inflammatory infiltrate and the absence of significant architectural disturbance (Figure 4). These findings were consistent with a diagnosis of a muco-submucosal elongated polyp.1, 2 Muco-submucosal elongated polyp of the GIT under white light. Muco-submucosal elongated polyp of the GIT under narrow band imaging (NBI). Muco-submucosal elongated polyp of the GIT following resection. Histology section (2X) through the polyp shows architecturally normal small intestinal mucosa (yellow arrow) overlying a core of submucosa containing abundant adipose tissue (blue arrow) with submucosal vessels (green arrows). No significant inflammation is seen. Enteric muco-submucosal elongated polyps are rare, benign gastrointestinal polyps with an elongated, cylindrical ‘worm-like’ endoscopic appearance that is a hallmark of the disease.2, 3 Initially identified in the colon,1 few cases have been reported in the small bowel.3 It is hypothesised that peristaltic movements serve as mechanical traction for redundant mucosa, creating a nidus for polyp growth in these mucosal areas. They can mimic a number of other enteric lesions, in particular prolapsing mucosal folds (associated with diverticular disease) and filiform polyps (associated with inflammatory bowel disease). Immunohistochemistry demonstrates positivity for endothelial vascular markers (CD31) and endothelial lymphatic vessels (D2-40/podoplanin). Endoscopic ultrasound (EUS) can demonstrate the mucosal and submucosal layers of the polyp, with characteristic microcystic components aiding the diagnosis. Symptomatic patients can be treated by endoscopic resection, although treatment may be considered in asymptomatic cases given case reports suggesting an associated risk of intussusception,4 diverticulitis5 and non-polypoid neoplasia.6, 7 Surveillance gastroscopy 3 and 12 months post resection did not reveal any residual polyps. The authors wish to acknowledge the patients who attend, and staff who work in the Endoscopy Unit and the contribution they make to clinical research. There was no funding source for this research. The authors have no conflicts of interest to declare. Data sharing not applicable to this article as no datasets were generated or analysed during the current study.

Images Clinical: Acro‐osteolysis: a complication of systemic sclerosis or rheumatoid arthritis?

The patient, a 63-year-old woman, was seen in the rheumatology clinic for anti-ribonucleoprotein (RNP) negative overlap syndrome (systemic sclerosis [SSc] and high-titre dual-seropositive rheumatoid arthritis [RA]), manifesting as Raynaud syndrome, sclerodactyly, interstitial lung disease, and synovitis. On examination, synovitis was palpated at the right second metacarpophalangeal joint, sclerodactyly was appreciated distal to metacarpophalangeal joints bilaterally, and there was striking fingertip pulp atrophy without any gangrene (Figure 1A). Nailfold capillaroscopy revealed dilatations and dropout. Hand radiographs (Figure 1B) revealed an erosion (white arrow), a distal tuft acro-osteolysis (blue arrows), and a band acro-osteolysis (red arrows). Acro-osteolysis, the absorption of distal bony phalanges, can be radiologically classified as either distal tuft, band, or combined (1). Isolated band pattern occurs in polyvinyl chloride (PVC) exposure, and isolated distal-tuft pattern can be appreciated commonly in SSc, Raynaud syndrome, thermal injury, dermatomyositis, and hyperparathyroidism. Rarely, the isolated tuft pattern can be seen in arthritides (like RA, psoriatic arthritis, and erosive osteoarthritis) with extension of destruction distally from the distal interphalangeal joint (2). The combined pattern occurs in SSc and hyperparathyroidism. The clinical quandary in our patient is that the acro-osteolysis could be from either RA or Raynaud syndrome. However, in the presence of both distinct tuft and band patterns, poorly controlled Raynaud syndrome was the likely culprit for acro-osteolysis rather than the rarely associated RA. Disclosure Form Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.