Successful Isolation Research Articles

High power short duration and very high power short duration protocol: a comparison between two effective strategies of atrial fibrillation transcatheter ablation with radiofrequency

Abstract Introduction Radiofrequency (RF) is the most widely used technique for atrial fibrillation (AF) ablation. Aiming to achieve durable pulmonary vein isolation (PVI) with reduced procedural time and potential thermal side effects, high power short duration (HPSD) and very-high power short duration (v-HPSD) protocols have been developed, exploiting the use of the latest catheter generations. Purpose To assess safety and efficacy of AF ablation using two distinct HPSD settings, aiming to determine the most effective protocol for trans-catheter RF AF ablation. Methods We conducted a retrospective study including patients with paroxysmal or persistent AF: 100 were treated with the HPSD protocol and 100 patients with the v-HPSD one. In the HPSD protocol, RF energy at 40 W was applied for up to 20 seconds for the anterior segments of the pulmonary vein (PV), and 50 W up to 10 seconds for the posterior segments of the PV and the posterior wall (PW). Conversely, in the v-HPSD protocol RF pulses were applied at 50 W with an ablation index (AI) 500 in the anterior segments of PV and 90 W up to 4 sec for the posterior segment of the PV and the PW. Safety and efficacy were assessed during the procedure, during the hospital stay and throughout the entire follow-up duration. Results No relevant clinical and echocardiographic differences were identified between the two groups. Successful PVI and PW isolation was achieved in all cases. The v-HPSD group demonstrated a higher first-pass isolation (FPI) rate compared to the HPSD group. In contrast, the HPSD group exhibited a greater impedance drop (ID), supported by a higher contact force (CF). The RF total time, the procedural time, and the dose-area product (DAP) were significantly lower in the v-HPSD group. No periprocedural complications were reported. During the follow-up no significant differences in AF recurrence rates have been observed. Conclusions The absence of procedural complications underscores the high safety of both protocols. In our study, the v-HPSD group exhibited a superior FPI rate, indicative of enhanced acute efficacy; however it is crucial to underline that the HPSD group included a higher proportion of patients with a history of prior AF ablation. The more elevated ID observed in the HPSD group, indicating the exceptional quality of lesions, could be related to the major conductive heating component compared to v-HPSD. This results in deeper lesions and a more significant ID. Conversely, the brief duration of applications in the v-HPSD protocol contributes to reduce procedural times and diminish radiation exposure. Despite procedural disparities, the follow-up period reveals a low recurrence rate of AF in both groups, emphasizing the effectiveness of both HPSD and v-HPSD protocols in AF treatment.Kaplan-Meier Curve

Radiofrequency catheter ablation for redo procedures after pulmonary vein isolation with the cryoballoon technique: 9-year outcome

Abstract Catheter ablation has become the first line of therapy in patients with symptomatic, recurrent, drug-refractory atrial fibrillation. Cryoablation has been shown to be a safe and effective technique for pulmonary vein isolation. However, there is a significant arrhythmia recurrence rate after cryoablation procedures and there are no established strategies for redo procedures in these patients. Therefore, we have summarized our experience with radiofrequency catheter ablation for redo procedures after pulmonary vein isolation with the cryoballoon technique (including an analysis of pulmonary vein conduction recovery patterns after procedures performed with the first or second generation cryoballoon). Methods Two hundred and twenty patients (paroxysmal AF: 140 patients, persistent AF: 80 patients) had to undergo a redo procedure after initially successful circumferential PV isolation with the cryoballoon technique (First generation: 110 patients (group A); second generation: 110 patients (group B)). The redo ablation procedures were performed using a segmental approach or a circumferential ablation strategy (three-dimensional mapping system) depending on the intra-procedural findings. Results During the redo procedure, a mean number of 1.6 re-conducting PVs were detected (using a circular mapping catheter; group A: 2.2 re-conducting PVs, group B: 1.0 re-conducting PVs). There was a slightly higher incidence of chronic PV reconnections related to the left-sided PV ostia than to the right-sided PVs in both groups. Furthermore, sites of chronic PV reconnection were found more frequently in the inferior parts of the PV ostia than in the superior parts. In 97 patients in group A, a segmental approach was sufficient to eliminate the residual PV conduction because there were only a few recovered PV fibers (1-3 reconnected PVs; group A1). In the remaining 13 patients in group A, a circumferential ablation strategy was used because of a complete recovery of the PV-LA conduction of all four pulmonary veins (group A2). In group B, a segmental approach was sufficient in nearly all patients (109/110) because there was only a minor reconnection of 1-2 PVs. All recovered PVs could be isolated sucessfully again. At 108-month follow-up, 69.1 % of all patients were free from an arrhythmia recurrence (152/220 patients; group A: 72/110 patients (65.5 %), group B: 80/110 patients (72.3 %)). There were no major complications in both groups. Conclusions In patients with an initial circumferential PVI using the cryoballoon technique, a repeat ablation procedure can be performed safely and effectively using radiofrequency catheter ablation. In most cases only a few re-conducting PV fibers were found and therefore, a segmental re-ablation approach seems to be sufficient in the majority of patients (especially in patients treated with the second generation cryoballoon).

Safety and efficacy outcomes in 100 consecutive cases of pulsed field ablation

Abstract Background Pulsed field ablation (PFA) an emerging technology for ablation of atrial fibrillation (AF). This non-thermal ablation modality uses ultrarapid electrical pulses to destabilise cell membranes and can selectively ablate myocardial tissue. Successful pulmonary vein isolation (PVI) and reductions in procedure times compared to other modalities have been observed in initial studies. Aim To report initial outcomes and fluoroscopic times in the first 100 consecutive cases using PFA in AF ablation. Methods The first 100 consecutive PFA cases carried out by a single operator in a single centre were examined. All cases were performed under general anaesthesia, using ultrasound-guided vascular access and TOE-guided transseptal puncture. Outcomes were recorded from the first case in June 2022 to the present day. Electroanatomic mapping (EAM) was carried out using two proprietary systems. Results Procedural information and follow-up was achieved in all 100 patients (see table). The majority (77) were male. Mean age 61. Cardiovascular comorbidities included: hypertension (41), heart failure (12), ischaemic heart disease (10), stroke (4), diabetes mellitus (3). Antiarrhythmic drugs were used by 45 patients (Amiodarone in 22, Dronedarone in 18, Flecainide in 10, Sotalol in 8, Mexiletine in 1) with 55 taking beta blockers only or no rhythm control drugs. Persistent AF accounted for 57 cases, and 91 patients had no prior ablation procedure. Median CHA2DS2VASC 1. Warfarin was used on 1 patient, the other 99 patients underwent ablation on uninterrupted DOAC, most commonly Apixaban. EAM was conducted in 59 patients. Stand-alone PVI was carried out in 68, while 30 underwent an additional posterior wall box isolation, and a mitral isthmus line was added in a further 2 who had atrial flutter (AFl) during the procedure following successful PVI. There were no serious peri-procedural complications. (vascular access complications, pericardial effusion, stroke or death). All 100 patients were discharged following a one-night stay. Clinical pericarditis without effusion occurred in 1 patient on day 2, and resolved with a short course of Colchicine. Mean fluoroscopy time was 9minutes, 12seconds, and reductions in fluoroscopy times correlated significantly with case number (see figure). Mean fluoroscopy time was 2mins, 30secs higher where EAM was used. Sinus rhythm was achieved in 100%. Atrial arrhythmia recurred in 12 patients, 7 with AF and 3 atrial flutter, 2 with typical symptoms which could not be documented. Two of the recurrences were within 24 hours of the procedure. Conclusions This registry data shows that PFA was used to achieve PVI safely, with effective additional substrate ablation also demonstrated. There were no serious peri-procedural complications, and procedural improvements in fluoroscopic times were observed throughout the 100 cases. Long term follow-up data is required to validate the safety and efficacy of this new technology.

LINAC-Based STereotactic Arrhythmia Radioablation (STAR) for paroxysmal atrial fibrillation in elderly: a prospective phase II trial

Abstract Background and aims Stereotactic arrhythmia radioablation (STAR) is a novel therapeutic approach for cardiac arrhythmias. The aim of this trial is to investigate the feasibility of STAR for the treatment of paroxysmal atrial fibrillation (AF) in elderly patients. Method inclusion criteria were: age > 70 years, symptomatic AF, antiarrhythmic drugs failure or intolerance. All patients underwent to 4D cardiac Computed Tomography simulation. The clinical target volume was identified in the area around pulmonary veins (PV). STAR was performed with a total dose of 25 Gy (single fraction) delivered in 3 minutes. Results Twenty patients were enrolled and 18 underwent STAR. One patient withdrew informed consent before treatment and 1 patient was excluded due to unfavorable esophagus position. With a median follow-up (FU) of 16 months (range 12-23), no acute toxicity more than grade 3 was reported. Five patients had a grade 1 esophagitis 24 hours after STAR; eight patients had an asymptomatic grade 1 pericardial effusion, one patient had a torsade de pointes treated effectively by electrical cardioversion and subsequent cardiac ICD implantation. Most patients had a significant reduction in AF episodes. Five patients, due to arrhythmias recurrences after STAR, performed electrophysiological study documenting successful PV isolation. Finally, a significant improvement of quality of life was documented (48 ± 15 at enrollment vs 75 ± 15 at 12 months FU; p < 0.001). Conclusion The present phase II trial demonstrated the feasibility of STAR in paroxysmal AF elderly patients and its potential role in increasing the quality of life. Surely, more robust data are needed about safety and efficacy.

Characterization of conduction recovery and atrial electrophysiological properties after pulmonary vein isolation using pulsed field ablation

Abstract Background Pulsed field ablation (PFA) is a relatively new technology for isolation of pulmonary veins in patients with atrial fibrillation (AF). Data addressing reasons for recurrent atrial fibrillation despite primarily successful pulmonary vein isolation (PVI) using PFA are scarce, due to an up to date limited number of patients treated this way. Objective The aim of this study was to analyze electrophysiological characteristics of reconduction and / or left atrial substrate of patients referred to our center for Re-Do procedures for recurrent AF after an initial PVI using PFA. Methods 90 patients (mean age 66±9 years, 69 male (77%)) had been treated in our center from November 2021 to July 2023 with PVI using PFA. 9 (10%) of these patients were referred for Re-Do procedures. These were performed by radiofrequency ablation (RFA) using Carto system including high density mapping and high power / short duration (HPSD) ablation. We analyzed location of PV reconnection and low voltage areas (LVA) in the left atria. Results 7 out of 9 patients (77%) presented with reconnections of pulmonary veins. In one patient a single vein showed reconduction (RSPV), in 5 patients 2 veins were conducting (1x LSPV, 3x LIPV, 1 left sided common os (LCo), 1x RSPV, 3x RIPV). None of the patients showed 3 or 4 reconnected veins. Areas of reconduction in each vein were: LSPV 1x ridge, 1x posterior; LIPV 1x posterior, 1x anterior and posterior; LCo 1x posterior, RSPV 1x anterior, 2x carina, 1x anterior and posterior; RIPV 1x complete, 2x carina. In 7 patients a fibrotic atrial cardiomyopathy (FACM) was diagnosed via high density mapping of LVA’s. In 2 of these patients all 4 pulmonary veins were chronically isolated after the initial PVI. All patients except one (very small anterior LVA) with FACM ≥1 were treated with additional linear or encircling lesions according to the individual extent of the fibrotic areas. 2 patients had no LVA’s detectable. In one of those 2 patients 2 veins had reconnected. The other patient had chronically isolated veins (no proof of dormant conduction with adenosine) and no detectable non-PV-triggers under isoprenaline. Conclusion In the population of patients undergoing PVI using PFA in our center, only 10% had clinically relevant recurrences leading to the necessity of a Re-Do procedure. Most patients (77%) in this setting had reconnections of pulmonary veins. There is a tendency of posterior reconnections of the left pulmonary veins and reconnections of the carina of the right pulmonary veins, but the number of patients is too small to clearly define predilection sites that have to be paid attention to when using PFA. Additionally, left atrial substrate is an important problem in patients with recurrent AF despite primarily successful PVI and has to be considered and thoroughly addressed in Re-Do procedures.Reconnection of LSPV and anterior LVAAblation of RSPV and LSPV (posterior)

Very high-power short duration ablation metrics predictors of successful pulmonary vein isolation in atrial fibrillation ablation

Abstract Background Previous studies have shown that very high-power short duration (vHPSD) is a safe ablation modality, with similar rate of first pass isolation (FPI) but faster ablation times compared to standard CLOSE protocol guided ablation. While CLOSE protocol uses ablation index to guide energy titration no such index exists for vHPSD ablations yet. Purpose Our aim was to evaluate ablation metrics as predictors of FPI in atrial fibrillation ablation (AF) using vHPSD ablation modality. Methods In a single centre retrospective analysis, we analysed consecutive patients treated for paroxysmal (PAF) or persistent atrial fibrillation (PeAF) with PVI using vHPSD ablation from May 2021 to January 2023. We excluded patients with previous PVI procedures. The analysis was done via a cloud-based commercially available ablation analysis tool CARTONET. We analysed catheter stability, average contact force, absolute impedance drop, number of ablations and cumulative ablation time in relation to first pass isolation (FAAVI – first attempt all veins isolated). Results This is the first larger data study to evaluate ablation metrics in vHPSD using commercially available CARTONET (Figure 1). Based on the inclusion criteria 150 patients were included in the analysis. Baseline characteristics and procedural metrics are presented in Figure 2 - Table. We observed a numerical trend towards higher FAAVI rate with increasing patients number (p=0.10). Complication rate was low (1 pericardial effusion requiring drainage and 1 vascular access site complication). Ablation metrics analysis yielded statistical differences between FAAVI and no FAAVI groups (Figure 2 - Table). Multivariate analysis identified average contact force (odds ratio (OR) 1.001; 95% confidence interval (CI): 0.999-1.003; p=0.047) and catheter stability (OR 0.985; 95% CI: 0.973-0.997; p=0.019) to be independent predictors of FAAVI. Additionally, number of applications (OR 1.000; 95% CI: 0.999-1.000; p=0.042) and total ablation time (OR 0.995; 95% CI: 0.991-0.999; p=0.021) were also independent predictors of FAAVI, possibly indicating larger vein and/or ablation circumferent line to be predictive of no FAAVI. Catheter stability of less than 1.16mm (AUC 0.61; p=0.015) was shown to be discriminative of FAAVI, however discrimination value was poor. Average contact force was not discriminative of FAAVI (AUC 0.58; p=0.105) in our patient cohort. Conclusion Average contact force and catheter stability were predictive of first pass isolation, however only catheter stability was discriminative of FAAVI. Larger data with standardised ablation protocol (interlesion distance) and wider range of ablation metrics is needed to corroborate and further build on these early findings.

Increased left atrial pressure is associated with fibrosis, elevated mechanical load and ventricular diastolic dysfunction in patients undergoing AF catheter ablation

Abstract Background Increased left atrial filling pressures might be a hallmark feature of atrial cardiomyopathy which has been associated with an increased incidence of atrial fibrillation (AF) recurrence even after successful pulmonary vein isolation (PVI). The interplay between left atrial pressure, measured during the ablation procedure, and other parameters characterising atrial and ventricular remodelling in patients with AF remains elusive. Methods and Results Between 2018 and 2022, 182 patients undergoing PVI for paroxysmal or persistent AF were included in the study. Mean left atrial pressure (mLAP) was measured invasively during the ablation procedure after transseptal puncture. A mLAP higher than 15 mmHg was considered the cut-off value for LA hypertension. Bipolar high-density 3D electro-anatomical maps (Carto) obtained during the procedure were used to manually quantify low-voltage (<0.5 mV) and normal voltage areas of the LA surface and a global low-voltage/normal voltage ratio index was derived. Contemporary transthoracic echocardiography data were included to evaluate LV systolic and diastolic function and blood samples were obtained post-procedurally from all patients. In bivariate linear regression analysis, mLAP reached only modest correlation with E/e’ as an imaging marker of diastolic dysfunction (R=0.31, p=0.005) (Figure 1A), with particular differences in mLAP values between patients with marked diastolic impairment (E/e’ > 15) vs. subgroups with mild dysfunction ( 8 < E/e’ ≤ 15) or normal diastolic function (E/e’ ≤ 8 ) (Figure 1B), log NT proBNP (R=0.34, p<0.001) (Figure 1C) and low-voltage/normal voltage ratio index (R=0.21, p=0.014) (Figure 1D). For a total of 158 patients, data about 1 year recurrence of AF were available, of these 22 (13.9%) had a recurrence after two procedures using cryo-energy for the index PVI and radiofrequency ablation for the re-PVI (second procedure). A Kaplan-Meier analysis and log-rank test showed a trend but no statistical significance regarding an increased AF recurrence rate between patients with and without LA hypertension (χ2 = 2.63, p= 0.09) (Figure 2). Conclusion Direct intra-procedural invasive measurement of LA pressures can offer an important and convenient novel piece of information for patients undergoing catheter ablation procedures for AF, with potential implication for post-procedural recurrence risk stratification. Atrial hypertension is only partially related to LV diastolic impairment, atrial fibrosis and myocardial mechanical load burden.

A snapshot of bacterial endophytes isolated from the roots of Vetiver grass (Chrysopogon zizanioides) grown at Bien Hoa airbase, Dong Nai province

Vetiver grass (Chrysopogon zizanioides) with a strong root system has been widely used for environmental pollution treatment. Recently, this grass has been cultivated at Bien Hoa airbase to mitigate dioxin concentration in the contaminated soil. Bacterial endophytes have been recognized to play key roles in plant growth promotion and responses of plant hosts to environmental factors. However, a beneficial association between endophytic bacteria and Vetiver grass root system grown in dioxin-contaminated soil has not been elucidated. In the present study, we isolated sixteen endophytic bacterial strains from the roots of Vetiver grass. The results of DNA sequencing of the 16S rRNA gene revealed that these culturable bacterial endophytes belong to 9 species of different genera. Four strains, including Klebsiella variicola B1, Enterobacter cloacae B4, Enterobacter kobei B6, and Enterobacter cloacae B11, produce high amounts of indol acetic acid (IAA). Strains K. variicola B1 and E. cloacae B4 also produce phytase and phosphatase to dissolve phytate and phosphate, respectively. These strains were selected to evaluate their abilities in promoting the growth of tomato plants as a model. After 28 days of inoculation with the tested strains through the roots, tomato plants grew 19% to 22% faster than the control plants. Conclusively, this study shows for the first time the successful isolation of endophytic bacteria from the roots of Vetiver grass cultivated in dioxin-contaminated soil, and some culturable bacterial strains exhibit as promising candidates for plant growth promotion.

Retinal pigment epithelial cell culture

Objective: Retinal pigment epithelial cells (RPEs), as the main cellular component of the preretinal membrane, whose excessive proliferation can lead to the development of proliferative vitreoretinopathy as interaction with other cellular components and intercellular substance. Here, we developed an effective method to culture RPEs so as to provide effective cell source for later experimental usage. Methods: The harvested of eye cup that retains the retinal pigment epithelium was gently washed three times with phosphate buffered saline (PBS), and was added with 0.02 mg/ml dispase enzyme, which was cut into small pieces and then placed in the incubator for digestion for about half an hour. Subsequently, gently blowing was performed multiple times to detach the RPEs from the retina to collect the RPEs suspension. After implantation into the culture dish, when the cells were grown and covered with 80-90% of the bottom of the bottle, digestion of the cells is carried out with 0.25% trypsin. After removing them from the wall, the digested cell suspension was collected, followed by addition of Dulbecco's modified Eagle medium/Nutrient Mixture F-12 (DMEM/F12) to stop digestion. The mixture was subject to centrifuge at 1000 r/min for 8 min, with the supernatant discarded, and then the cells located in bottom were passaged at 1:3 ratios. During the process, the morphology and viability were observed and cell identification were also performed. Results: Primary cultured cells began to adhere to the wall at 4 h, characterized with a flat and polygonal morphology, rich in pigment particles. On 3 days, there was a significant increase in cell numbers accompanied by cluster formation, resulting in a stabilized cobblestone-like appearance. By 5 days, cells elongated and formed dense clusters. Growth curve analysis revealed robust proliferation at 3 and 5 days. Immunofluorescence staining confirmed that over 90% of the cells were positive for RPE-65, indicating successful isolation and culture of pure rat RPEs. Conclusions: The RPEs cultured by the above method are in good growth and it can be used for further experimental studies.

LINAC–BASED STEREOTACTIC ARRHYTHMIA RADIOABLATION (STAR) FOR PAROXYSMAL ATRIAL FIBRILLATION IN ELDERLY: A PROSPECTIVE PHASE II TRIAL

Abstract Background and Aims The aim of this trial is to investigate the feasibility of radiotherapy for the treatment of paroxysmal atrial fibrillation (AF) in elderly patients. Method inclusion criteria were: age > 70 years, symptomatic AF, antiarrhythmic drugs failure or intolerance. All patients underwent to 4D cardiac Computed Tomography simulation. The clinical target volume was identified in the area around pulmonary veins (PV). STAR was performed with a total dose of 25 Gy (single fraction) delivered in 3 minutes. Results Twenty patients were enrolled and 18 underwent STAR. One patient withdrew informed consent before treatment and 1 patient was excluded due to unfavorable esophagus position. With a median follow–up (FU) of 16 months (range 12–23), no acute toxicity more than grade 3 was reported. Five patients had a grade 1 esophagitis 24 hours after STAR; eight patients had an asymptomatic grade 1 pericardial effusion, one patient had a torsade de pointes treated effectively by electrical cardioversion and subsequent cardiac ICD implantation. Most patients had a significant reduction in AF episodes. Five patients, due to arrhythmias recurrences after STAR, performed electrophysiological study documenting successful PV isolation. Finally, a significant improvement of quality of life was documented (48 ± 15 at enrollment vs 75 ± 15 at 12 months FU; p < 0.001). Conclusion The present phase II trial demonstrated the feasibility of STAR in paroxysmal AF elderly patients and its potential role in increasing the quality of life. Surely, more robust data are needed about safety and efficacy.

ISOLATED PINEAPPLE PEEL MICROCELLULOSE AS A MATRIX FOR POLYPYRROLE-BASED CAPACITOR

This study investigates the viability of utilizing microcellulose extracted from pineapple peel waste as a sustainable and cost-effective matrix material for polypyrrole (PPy)-based capacitors. A novel PPy/microcellulose composite was synthesized with varying pyrrole volumes (1-2 mL) and characterized using Fourier Transform Infrared (FTIR) and X-ray diffraction (XRD) analyses. FTIR analysis confirmed successful cellulose isolation, while XRD indicated a similarity between the extracted pineapple peel and commercial cellulose. Capacitor cells were fabricated using the synthesized composites, and their capacitance performance was evaluated. Notably, cells containing 2 mL of PPy exhibited the highest capacitance values. Additionally, the source of cellulose had minimal influence on the resulting capacitance. This study suggests that microcellulose derived from pineapple peel waste holds promise as a sustainable alternative to traditional matrix materials for high-performance capacitors.

Comparative characterisation of extracellular vesicles from canine and human plasma: a necessary step in biomarker discovery

Extracellular Vesicles (EV) have become an interesting focus as novel biomarkers of disease and are increasingly reported upon in humans and other species. The Minimal Information for Studies of Extracellular Vesicles 2018 (MISEV2018) guidelines were published to improve rigor and standardisation within the EV field and provide a framework for the reliable isolation and characterisation of EV populations. However, this rigor and standardisation has been challenging in the area of comparative medicine. Herein we present the successful isolation of EVs from human and canine plasma using Size Exclusion Chromatography and characterise these EVs according to best international practice. This study provides evidence for the reliable comparison of human and canine EVs isolated by this approach, and a baseline description of the EVs from healthy dogs to inform future biomarker studies. This work also demonstrates that the MISEV2018 guidelines can be successfully applied to EVs isolated from canine plasma.

Redox- and Charge-State Dependent Trends in 5, 6, and 7-Membered Boron Heterocycles: A Neutral Ligand Coordination Chemistry Approach to Boracyclic Cations, Anions, and Radicals.

ConspectusBoron heterocycles represent an important subset of heteroatom-incorporated rings, attracting attention from organic, inorganic, and materials chemists. The empty pz orbital at the boron center makes them stand out as quintessential Lewis acidic molecules, also serving as a means to modulate electronic structure and photophysical properties in a facile manner. As boracycles are ripe for extensive functionalization, they are used in catalysis, chemical biology, materials science, and continue to be explored as chemical synthons for conjugated materials and reagents. Neutral boron(III)-incorporated polycyclic molecules are some of the most studied types of boracycles, and understanding their redox transformations is important for applications relying on electron transfer and charge transport. While relevant redox species can often be electrochemically observed, it remains challenging to isolate and characterize boracycles where the boron center and/or polycyclic skeleton have been chemically reduced.We describe our recent work isolating 5-, 6-, and 7-membered boracyclic radicals, anions, and cations, focusing on stabilization strategies, ligand-mediated bonding situations, and reactivity. We present a versatile neutral ligand coordination chemistry approach that permits the transformation of boracycles from potent electrophiles to powerful nucleophilic heterocycles that facilitate diverse electron transfer and bond activation chemistry. Although there are a wide range of suitable stabilizing ligands, we have employed both diamino-N-heterocyclic carbenes (NHCs) and cyclic(alkyl)(amino) carbenes (CAACs), which led to boracycles with tunable electronic structures and aromaticity trends. We highlight successful isolation of borafluorene radicals and demonstrate their reversible redox behavior, undergoing oxidation to the cation or reduction to the anion. The borafluorene anion is a chemical synthon that has been used to prepare boryl main-group and transition-metal bonds, luminescent oxabora-spirocycles, borafluorenate-crown ethers, and CO-releasing molecules via carbon dioxide activation. We expanded to 6-membered boracycles and characterized neutral bis(NHC-supported 9-boraphenanthrene)s and the corresponding bis(CAAC-stabilized 9-boraphenanthrene) biradical. We detail the interconvertible multiredox states of boraphenalene, where the boraphenalenyl radical, anion, and cation mimic the charge-states of the all-hydrocarbon analogue. Reactivity studies of the boraphenalenyl anion displayed unusual nucleophilic reactivity at multiple sites on the periphery of the boraphenalenyl tricyclic scaffold. Reduced borepins, 7-membered boron containing heterocycles, have also been isolated. We used a stepwise one-pot synthesis combining the halo-borepin precursor, CAAC, and KC8 to afford the monomeric borepin radicals and anions. The π-system was extended to contain two borepin rings fused in a pentacyclic scaffold, which permitted isolation of diborepin biradicals and a diborepin containing a dibora-quinone core.Our goal is to provide a guide explaining the current structure-function trends and isolation strategies for redox-active boron-incorporated polycyclic molecules to initiate the rational design and use of these types of compounds across a vast chemical space.

Phenotypic and Functional Characterization of Bovine Adipose-Derived Mesenchymal Stromal Cells.

Mesenchymal stem cells (MSCs) are increasingly trialed in cellular therapy applications in humans. They can also be applied to treat a range of diseases in animals, particularly in cattle to combat inflammatory conditions and aging-associated degenerative disorders. We sought to demonstrate the feasibility of obtaining MSCs from adipose tissue and characterizing them using established assays. Bovine adipose MSCs (BvAdMSCs) were isolated using in-house optimized tissue digestion protocols and characterized by performing a colony formation assay, cell growth assessments, cell surface marker analysis by immunocytochemistry and flow cytometry, osteogenic and adipogenic differentiation, and secretion of indoleamine 2,3-dioxygenease (IDO). Our results demonstrate the feasibility of successful MSC isolation and culture expansion from bovine adipose tissues with characteristic features of colony formation, in vitro multilineage differentiation into osteogenic and adipogenic lineages, and cell surface marker expression of CD105, CD73, CD90, CD44, and CD166 with negative expression of CD45. BvAdMSCs secreted significant amounts of IDO with or without interferon-gamma stimulation, indicating ability for immunomodulation. We report a viable approach to obtaining autologous adipose-derived MSCs that can be applied as potential adjuvant cell therapy for tissue repair and regeneration in cattle. Our methodology can be utilized by veterinary cell therapy labs for preparing MSCs for disease management in cattle.

Re-discovery of MS-347a as a fungicide candidate through a new drug discovery platform with a multidrug-sensitive Saccharomyces cerevisiae screening system and the introduction of a global secondary metabolism regulator, laeA gene.

We found that the culture broth of fungi showed anti-fungal activity against multidrug-sensitive budding yeast. However, we could not identify the anti-fungal compound due to the small quantity. Therefore, we attempted to increase the productivity of the target compound by the introduction of a global secondary metabolism regulator, laeA to the strain, which led to the successful isolation of 10-folds greater amount of MS-347a (1) than Aspergillus sp. FKI-5362. Compound 1 was not effective against Candida albicans and the detailed anti-fungal activity of 1 remains unverified. After our anti-fungal activity screening, 1 was found to inhibit the growth of broad plant pathogenic fungal species belonging to the Ascomycota. It is noteworthy that 1 showed little insecticidal activity against silkworms, suggesting its selective biological activity against plant pathogenic fungi. Our study implies that the combination strategy of multidrug-sensitive yeast and the introduction of laeA is useful for new anti-fungal drug discovery.

High-frequency optical coherence tomography for endovascular management of cerebral aneurysms.

Endovascular management of intracranial aneurysms has become the mainstay of treatment in recent years; however, retreatment rates remain as high as 1 in 5. High-frequency optical coherence tomography (HF-OCT) is an emerging imaging modality for the assessment, treatment and follow-up of cerebral aneurysms. EMBASE and SCOPUS databases were searched for studies relating to the management of intracranial aneurysm with OCT. A combination of keywords were used including 'cerebral aneurysm', 'intracranial aneurysm', 'high-frequency optical coherence tomography', 'optical coherence tomography', and 'optical frequency domain imaging'. There were 23 papers included in this review. For the assessment of intracranial aneurysm, OCT was able to accurately assess aneurysm morphology as well as detailed analysis of arterial wall layers. During IA treatment, OCT was used to assess and troubleshoot stent placement to optimise successful isolation from the circulation. In the follow-up period, endothelial growth patterns were visualised by OCT imaging. OCT shows promise for the treatment of IAs at all stages of management. Due to the novel development of HF-OCT, there is limited longitudinal data in human studies. Further research in this area is required with a focus specifically on long-term treatment outcomes in humans.

Protective effects of canthaxanthin-loaded seminal exosomes on the quality of human spermatozoa during cryopreservation

Sperm cryopreservation is a common strategy for preserving male fertility; however, it may cause detrimental alterations in the structure and biological role of spermatozoa. The objective of this study is to mitigate the damages caused by cryopreservation through the use of canthaxanthin-loaded seminal exosomes (CAN-loaded EXO). To achieve this, Exosomes were isolated from the human seminal fluid through serial ultracentrifugation and characterized using different methods. Canthaxanthin was loaded into exosomes using the sonication method and incubated with spermatozoa for 1 h. Then the semen was mixed with CryoSperm medium and transferred into straws. The straws were initially placed in nitrogen vapor and then submerged in liquid nitrogen. After one month, the samples were thawed, and sperm parameters, lipid peroxidation, total antioxidant capacity (TAC), reactive oxygen species (ROS) levels, sperm DNA fragmentation (SDF), and sperm apoptosis were assessed. The results demonstrated the successful isolation of exosomes with a spherical morphology, a particle size of 104.5 nm, and a zeta potential of −12.32 mV. Canthaxanthin was loaded into exosomes with an encapsulation efficiency of 63.7 %. Motility and vitality of spermatozoa were improved in the presence of CAN-loaded EXO compared to the control group (p < 0.05). Incubation of spermatozoa with CAN-loaded EXO enhanced TAC levels and decreased ROS levels, lipid peroxidation, SDF, and apoptosis compared to the control group (p < 0.05). However, CAN-loaded EXO had no significant effect on the morphology of spermatozoa. These findings suggest that exosomes have the potential to serve as a novel drug delivery platform for protecting spermatozoa from cryodamage while enhancing the bioavailability of antioxidants.

Helicopter Planet Gear Rim Crack Diagnosis and Trending Using Cepstrum Editing Enhanced with Deconvolution.

Detecting gear rim fatigue cracks using vibration signal analysis is often a challenging task, which typically requires a series of signal processing steps to detect and enhance fault features. This task becomes even harder in helicopter planetary gearboxes due to the complex interactions between different gear sets and the presence of vibration from sources other than the planetary gear set. In this paper, we propose an effectual processing algorithm to isolate and enhance rim crack features and to trend crack growth in planet gears. The algorithm is based on using cepstrum editing (or liftering) of the hunting-tooth synchronous averaged signals (angular domain) to extract harmonics and sidebands of the planet gears and low-pass filtering and minimum entropy deconvolution (MED) to enhance extracted fault features. The algorithm has been successfully applied to a vibration dataset collected from a planet gear rim crack propagation test undertaken in the Helicopter Transmission Test Facility (HTTF) at DSTG Melbourne. In this test, a seeded notch generated by an electric discharge machine (EDM) was used to initiate a fatigue crack that propagated through the gear rim body over 94 load cycles. The proposed algorithm demonstrated a successful isolation of incipient fault features and provided a reliable trending capability to monitor crack progression. Results of a comparative analysis showed that the proposed algorithm outperformed the traditional signal processing approach.

Study on the mechanism of quercetin inducing mesenchymal stem cells to differentiate into fibroblasts through TGF-β1 and IGF-1

BackgroundStem cell differentiation has opened up new avenues for disease treatment, tissue repair, and drug development in the study of regenerative medicine, and has huge application prospects. This study aimed to explore the mechanism of quercetin on the differentiation of mesenchymal stem cells (MSCs) into fibroblasts. MethodsIn this study, cell differentiation experiments and flow cytometry were used to detect the successful isolation of bone marrow MSCs from SD rats. Quercetin at 5, 10, and 20 μM was used as low, medium, and high doses to intervene in MSCs. The cell viability changes of ligament fibroblasts at 24, 48, and 72 hours after quercetin treatment were detected using a CCK-8 cell counting kit. Cell proliferative capacity was determined by flow cytometry. RT-qPCR measured the relative expression levels of TGF-β1, IGF-1, COL-Ⅰ, COL-Ⅲ, FN (fibronectin), and TNMD (Tenomodulin) in different experimental groups. Molecular docking experiments were conducted to explore the binding effect of quercetin on TGF-β1 and IGF-1 proteins. ResultsFlow cytometry verified the successful isolation of MSCs, which had high expression of CD29 and CD73, while lower expression of CD90 and CD45. Experimental results show that low and medium doses of quercetin can enhance cell proliferation, while high doses have no significant effect on cells. Detection of cell proliferation through flow cytometry yielded similar results to CCK-8. Transwell experiments have shown that low and medium doses of quercetin can increase cell migration ability. In addition, RT-qPCR detection showed that quercetin can increase the mRNA expression of TGF-β1 and IGF-1, and promote the expression of COL-Ⅰ, COL-Ⅲ, FN, and TNMD genes in ligament fibroblasts. Molecular docking results showed that quercetin can bind firmly to TGF-β1 and IGF-1. ConclusionOverall, this study revealed the morphological characteristics and identification of MSCs, as well as the regulatory mechanism of quercetin on the behavior of ligament fibroblasts. Quercetin affects the proliferation and gene expression of ligament fibroblasts by regulating the expression of TGF-β1 and IGF-1, which may provide a new perspective for biomedical research on the skeletal system.

Parallel biosensor platform for the detection of carbapenemase-producing E. coli in spiked food and water samples

The rise of carbapenem-resistant E. coli, specifically carbapenemase-producing (CP) strains, in biological samples needs attention. Early detection is crucial in minimizing and controlling their detrimental impact. However, their rapid identification directly from contaminated samples has not been documented well. This study presented an affordable and rapid platform for extraction and detection of CP E. coli, particularly Klebsiella pneumoniae carbapenemase (KPC)-producing E. coli from spiked food and water samples. Glycan-coated magnetic nanoparticles (gMNPs) were utilized to extract the bacteria from contaminated buffer solution, tap water, romaine lettuce, ground beef, and chicken breast samples. The bacterial cell concentration by gMNPs was achieved in the presence of food microparticles and natural microflora. Transmission Electron Microscopy (TEM) illustrated the successful isolation of bacteria and their interaction with gMNPs. For detection, a parallel plasmonic biosensor using dextrin-coated gold nanoparticles (dGNPs) was developed. The biosensor successfully detected KPC-producing E. coli from pure culture by targeting uidA and blaKPC genes and did not require any PCR amplification. The stability of dGNPs, shown by their red appearance, indicated the presence of target DNA. In contrast, their agglomeration, given by their blue or purple color, indicated the absence of target DNA. This stability and agglomeration of the dGNPs were confirmed by TEM and quantified by absorbance spectrum measurements. Further, the designed biosensor platform successfully identified the DNA extracted from water and food samples contaminated with KPC-producing E. coli, with no false positives for the samples contaminated with non-target bacteria. The biosensor successfully detected the target organism, where the original concentration prior to magnetic extraction was 103 CFU/mL. The biosensor results were further confirmed with the standard PCR assay. As a proof-of-concept, these findings indicate promising applications of the integrated platform for cost-effective and rapid bacterial detection from complex matrices within <7 h. The gained insights may facilitate future application of this platform for its complete validation study to improve real-world applicability.