Isthmus Region Research Articles

Observations on the reproductive morphology of the female short-beaked echidna, Tachyglossus aculeatus.

Although monotremes diverged from the therian mammal lineage approximately 187 million years ago, they retain various plesiomorphic and/or reptilian-like anatomical and physiological characteristics. This study examined the morphology of juvenile and adult female reproductive tracts across various stages of the presumptive oestrous cycle, collected opportunistically from cadaver specimens submitted to wildlife hospitals during the breeding season. In adult females, ovaries had a convoluted cortex with follicles protruding from the ovarian surface. While protruding antral follicles were absent from the ovaries of juvenile echidnas, histological analysis identified early developing primordial and primary follicles embedded into the ovarian cortex. The infundibulum epithelial cells of the oviducts were secretory during the follicular phase but not at other stages, the ampulla region was secretory at all stages and is likely responsible for the mucoid layer deposited around the zona pellucida, and the isthmus region of the oviduct appeared to be responsible for initial deposition of the shell coat, as in marsupials. Female echidnas have two separate uteri, which never merge and enter separately into the urogenital sinus (UGS). This study confirmed that both uteri are functional and increase in glandular activity during the luteal phase. In the juvenile uteri, the endometrium was immature with minimal, small uterine glands. A muscular cervical region at the caudal extremity of each uterus, just before the cranial region of the UGS was defined by the absence of glandular tissue in all female echidnas, including the juveniles. There was no evidence of a definitive vaginal region. A clitoris was also detected that possessed a less developed but similar structural (homologous) anatomy to the male penis; urethral ducts while present did not appear to be patent.

Optimized isochronal late activation methods in the visualization and isthmus identification of ventricular tachycardia

BackgroundCatheter ablation of ventricular tachycardia (VT) during sinus rhythm often relies on isochronal late activation mapping (ILAM), a validated means of isthmus identification, whereby points are binned by local activation time (LAT) into 8 isochrones, and isthmus regions are identified as regions with isochronal crowding. The resulting output, however, is inherently discretized, and loss of LAT data occurs. To improve the precision of isthmus identification, we quantify isochronal density and assess the effect of increasing the number of isochrones used and the effectiveness of continuous metrics analogous to ILAM. ObjectiveThe objective of this study was to determine whether current practices in ILAM calculation are optimized for isthmus detection. MethodsPatients undergoing VT ablation were included if high-density maps in both VT and sinus or paced rhythms were available. Isochronal density was assessed at differing numbers of isochrones, and isthmus discrimination was assessed. Continuous metrics that mimicked ILAM by assessing the local distribution of LAT values—using interquartile range or the median absolute deviation—were also defined and assessed. ResultsEight electroanatomic maps (EAMs) were included. Isthmus discrimination improved progressively from a minimum area under the curve (AUC) of 0.600 when assessing the isochronal density of 8-isochrone EAMs to a maximum of 0.776 when assessing the density of 1000-isochrone EAMs (DeLong test, P < .0001). On logistic regression, the continuous metrics using interquartile range (AUC = 0.714) and median absolute deviation (AUC = 0.721) better discriminated isthmus identity than ILAM. ConclusionUsing more isochrones or using continuous ILAM analogues improves isthmus identification. By retaining more data, these metrics could increase the precision of VT ablation.

O-096 Human fallopian tube organoids provide a favorable environment for sperm motility

Abstract Study question Does a human fallopian tube (HFT) organoid model offer a favorable apical environment for human sperm survival and motility? Summary answer The apical compartment of a new model of human fallopian tube organoids provides after differentiation a favorable environment for sperm motility. What is known already Human fallopian tubes are the site of major events that are crucial for achieving an ongoing pregnancy, such as gamete survival and competence, fertilization steps, and preimplantation embryo development. In order to better understand the tubal physiology and tubal factors involved in these reproductive functions, and to improve still suboptimal in vitro conditions for gametes preparation and embryo culture during In Vitro Fertilization IVF, we sought to develop a human fallopian tube organoid model from isolated adult stem cells allowing spermatozoa coculture in the apical compartment. Study design, size, duration Over a two-year period, fallopian tube tissues were collected for organoid culture purposes from 10 “donor” patients undergoing bilateral salpingectomy by laparoscopy for definitive sterilization. After tissue digestion, adult stem cells from the isthmus and ampulla regions were separately seeded in 3D Matrigel and cultured with conventional growth factors for organoid culture and specific factors for differentiation of the female genital tract. Participants/materials, setting, methods HFT organoids were characterized by light microscopy, scanning and transmission electron microscopy, immunofluorescence and transcriptomic analysis. Following simultaneous organoid culture on specific inserts, spermatozoa from five donors were placed either in control media or in the apical compartment of colon or HFT organoids (isthmus and ampulla separately) for 96 hours. Vitality and motility were assessed at 0, 48, and 96 hours on 200 spermatozoa in each condition and in duplicate and compared using Wilcoxon test. Main results and the role of chance Specific fallopian tube differentiation of our model was confirmed by immunofluorescence, transcriptome analysis and electron microscopy observations that exhibited ciliary and secretory cells. We succeeded in releasing spermatozoa in the apical compartment of HFT organoids and in recovering them for sperm analysis. Sperm vitality values are similar in HFT organoids and in commercial sperm media. We demonstrated a superiority of HFT organoid apical compartment for sperm motility compared with other controls (colon organoids, organoid culture media, and conventional commercial sperm washing and fertilization media). At 48 hours of incubation, progressive sperm motility was higher in the apical compartment of HFT organoids (ampulla 30.6% ±17.3, isthmus 29.3% ±14.8) than in commercial fertilization media (15.3% ±14.6) (p &amp;lt; 0.05) and compared with all other conditions. At 96 hours progressive sperm motility was almost nil (&amp;lt;1%) in all conditions except for spermatozoa within HFT organoids (p &amp;lt; 0.05): 11.5% ±14.7 and 12.9% ±16.9 in ampulla and isthmus organoids, respectively. Limitations, reasons for caution This was an in vitro study in which conditions of organoid culture could not exactly mimic the in vivo environment of extracellular matrix and the vascularization of fallopian tubes. Wider implications of the findings This work opens up perspectives for better understanding of HFT physiology. For the first time, it highlights the possibility of developing HFT organoids for reproductive purposes. In the future, it could help us to improve gametes fertilizing abilities and culture conditions of embryos during human assisted reproductive technologies. Trial registration number not applicable

Automating aortic cross-sectional measurement of 3D aorta models.

Aortic dissection carries a mortality as high as 50%, but surgical palliation is also fraught with morbidity risks of stroke or paralysis. As such, a significant focus of medical decision making is on longitudinal aortic diameters. We hypothesize that three-dimensional (3D) modeling affords a more efficient methodology toward automated longitudinal aortic measurement. The first step is to automate the measurement of manually segmented 3D models of the aorta. We developed and validated an algorithm to analyze a 3D segmented aorta and output the maximum dimension of minimum cross-sectional areas in a stepwise progression from the diaphragm to the aortic root. Accordingly, the goal is to assess the diagnostic validity of the 3D modeling measurement as a substitute for existing 2D measurements. From January 2021 to June 2022, 66 3D non-contrast steady-state free precession magnetic resonance images of aortic pathology with clinical aortic measurements were identified; 3D aorta models were manually segmented. A novel mathematical algorithm was applied to each model to generate maximal aortic diameters from the diaphragm to the root, which were then correlated to clinical measurements. With a 76% success rate, we analyzed the resulting 50 3D aortic models utilizing the automated measurement tool. There was an excellent correlation between the automated measurement and the clinical measurement. The intra-class correlation coefficient and -value for each of the nine measured locations of the aorta were as follows: sinus of valsalva, 0.99, ; sino-tubular junction, 0.89, ; ascending aorta, 0.97, ; brachiocephalic artery, 0.96, ; transverse segment 1, 0.89, ; transverse segment 2, 0.93, ; isthmus region, 0.92, ; descending aorta, 0.96, ; and aorta at diaphragm, 0.3, . Automating diagnostic measurements that appease clinical confidence is a critical first step in a fully automated process. This tool demonstrates excellent correlation between measurements derived from manually segmented 3D models and the clinical measurements, laying the foundation for transitioning analytic methodologies from 2D to 3D.

Exploring the morphology of the glandula uropygialis in Denizli rooster: 3 tesla MRI and histological investigation

The aim of this study was to examine the preen gland (uropygial gland) of Denizli rooster, an endemic species for Turkey, both macroscopic and by magnetic resonance imaging and to present its histological formation. Five adult male subjects were used for this study. Although some of the findings of the preen gland in Denizli rooster were quite similar to the previous studies on the various avian species, widely branching secondary sinuses of the both two lobes of the gland were formed different from those. It was observed that the sinuses of these two lobes were connected to each other by forming passageway at the isthmus region of the gland. MR images showed bright white hyper-echoic features due to high fat secretion of the preen gland. Therefore, it was determined that the preen gland could be easily isolated from the surrounding tissues. It was also observed in the MR images that the gland in the Denizli cock has a pair of symmetrical bilateral lobes and is located on both sides. This connection gave rise to thought that the problems occurred by the blockage of the one of the primary canals can be solved by the compensation of another canal connected through this passageway. Thus, the secretion of the gland could be maintained properly.

Non-invasive assessment of the ventricular tachycardia isthmus during sinus rhythm

Abstract Background The ablation of ventricular tachycardias (VT) presents significant challenges due to the complex and time-consuming approaches involved in identifying arrhythmogenic regions. Combining non-invasive electrocardiographic imaging (ECGI) with endocardial mapping could potentially enhance the efficacy of interventions. Objective To evaluate the capability of ECGI in guiding operators towards areas of VT isthmuses during sinus rhythm. Methods Patients with scar-related VT, confirmed by late gadolinium enhancement cardiac magnetic resonance, were prospectively enrolled. We compared the areas of slowed conduction identified by ECGI with the VT sustaining regions identified endocardially. Simultaneous Electroanatomical Mapping (EAM) and ECGI mapping were performed during VT ablation procedures. In patients in whom a hemodynamically stable VT was maintained, the reentry circuit was mapped endocardially, and the ablation target was identified. The left ventricle was segmented into 9 regions, categorized as either VT-isthmus or non-VT isthmus based on EAM findings. Prior to ablation, local activation times (LAT) and conduction velocity (CV) ECGI sinus maps were computed. Slow conduction was quantified non-invasively by computing different ECGI metrics per region, including the mean and the standard deviation (SD) of LAT and CV, the regional Total Activation Time (rTAT) – time span between the earliest and latest activated nodes–, and the Slow Conduction Velocity (SCV) – the percentage of nodes where velocity falls below 60 cm/s -. Results The study included 20 consecutive patients with ischemic cardiomyopathy who were referred for VT ablation. A total of 21 regions linked to the VT isthmus were identified endocardially in 17 patients (age: 66.1±8.8 years, 94.1% male, left ventricular ejection fraction: 26.4±7.3%). Figure 1 illustrates the correlation between the VT circuit and the ECGI sinus map in two patients with extensive left ventricular fibrosis. ECGI metrics related to VT isthmuses exhibited a higher standard deviation in both LAT (18.1±2.0 vs 9.8±1.2 ms; p=0.001), and CV (50.4±4.7 vs 37.1±2.8 cm/s; p=0.011), and a greater percentage of nodes with slowed conduction (13.7±2.7 vs 7.4±1.6 %; p=0.029), compared to non-VT isthmus regions, Figure 2. Multivariate logistic regression analysis revealed that SD-LAT was the strongest predictor of VT isthmus localization. Conclusion ECGI has demonstrated the capability to pinpoint slowed conduction areas responsible for VT in sinus rhythm, showing promise in planning and guiding VT ablation strategies. This advancement paves the way for further research into using this non-invasive tool to improve risk stratification methods for ventricular arrhythmias.

A VERY COMPLEX CASE OF DORV TYPE FALLOT: A CASE REPORT

Abstract Double outlet right ventricle (DORV) is a rare CHD characterized by ventriculoarterial connection in which both great arteries arise entirely or predominantly from the right ventricle. Its prevalence is 0.9% of all CHDs. Several chromosomal abnormalities have been associated with DORV, including trisomy 13, trisomy 18, and chromosome 22q11 deletion. Hearts with DORV are an extremely heterogeneous group showing various morphological features, connections, and relationships at each level of the cardiac segments and intersegmental junctions. As a consequence, the clinical manifestations and required surgical procedures for patients with DORV are variable. The anatomical spectrum is higly variable: it can be associated with ventricular septal defect, transposition of the great arteries (TGA) and functional single ventricle. We report the case of an infant with prenatal diagnosis of CHD and finding partial duplication of the short arm of the X chromosome. Pregnant woman at 22 weeks comes to the outpatient clinic to perform follow–up ultrasound. At that site finding of CHD which was later confirmed at birth and therefore prostaglandin therapy was started. Echocardiogram showed a wide DIV from malalignment with antero–cephalic deviation of the conal septum with significant aortic destroposition configuring picture of double outlet right ventricle. It also presents a complex right efflux obstruction already at subvalvular pulmonary departure. The pulmonary valve presented dysplastic, with en dome motion, hypoplastic. Pulmonary perfusion appears to be provided predominantly by the Botallo‘s duct originating from the isthmic region of the aorta and leading with a long and tortuous course to the pulmonary confluence near the left pulmnary artery with high velocity flow. The remaining findings are normal. Therefore, in view of the clinical picture, he was subjected to palliative surgery of right systemic–pulmonary shunt between the brachiocephalic trunk and right pulmonary artery (modified Blalock–Taussing surgery) in 3.5mm PTFE and ligation of Botallo‘s duct. At subsequent follow–up, the systemic–pulmonary shunt appeared pervious with regular flow. Wide DIV from anterior malalignment with aorta cavalier to DIV. Severe stenosis at complex pulmonary outflow with max gradient up to 124mmHg with dynamic and valvular component. For the subsequent course of treatment, the patient will be discussed collegially.

White Isthmus Transcriptome Analysis Reveals the Mechanism of Translucent Eggshell Formation.

The presence of translucent eggshells is a type of egg quality issue that impacts egg sales. While many researchers have studied them, the exact mechanisms behind their formation remain unclear. In this study, we conducted a transcriptomic differential expression analysis of the isthmus region of the oviduct in both normal egg- and translucent egg-laying hens. The analysis revealed that differentially expressed gene pathways were predominantly concentrated in the synthesis, modification, and transport of eggshell membrane proteins, particularly collagen proteins, which provide structural support. These findings suggest that variations in the physical structure of the eggshell membrane, resulting from changes in its chemical composition, are the fundamental cause of translucent eggshell formation. This research provides a theoretical reference for reducing the occurrence of translucent eggs.

Biomechanical impact of different isthmus positions in mandibular first molar root canals: a finite element analysis.

This study used image-based finite element analysis (FEA) to assess the biomechanical changes in mandibular first molars resulting from alterations in the position of the root canal isthmus. A healthy mandibular first molar, characterized by two intact root canals and a cavity-free surface, was selected as the subject. A three-dimensional model for the molar was established using scanned images of the patient's mandibular teeth. Subsequently, four distinct finite element models were created, each representing varied root canal morphologies: non-isthmus (Group A), isthmus located at the upper 1/3 of the root (Group B), middle 1/3 of the root (Group C), and lower 1/3 of the root (Group D). A static load of 200 N was applied along the tooth's longitudinal axis on the occlusal surface to simulate regular chewing forces. The biomechanical assessment was conducted regarding the mechanical stress profile within the root dentin. The equivalent stress (Von Mises stress) was used to assess the biomechanical features of mandibular teeth under mechanical loading. In Group A (without an isthmus), the maximum stress was 22.2MPa, while experimental groups with an isthmus exhibited higher stresses, reaching up to 29.4MPa. All maximum stresses were concentrated near the apical foramen. The presence of the isthmus modified the stress distribution in the dentin wall of the tooth canal. Notably, dentin stresses at specific locations demonstrated differences: at 8mm from the root tip, Group B: 13.6MPa vs. Group A: 11.4MPa; at 3mm from the root tip, Group C: 14.2MPa vs. Group A: 4.5MPa; at 1mm from the root tip, Group D: 25.1MPa vs. Group A: 10.3MPa. The maximum stress in the root canal dentin within the isthmus region was located either at the top or bottom of the isthmus. A root canal isthmus modifies the stress profile within the dentin. The maximum stress occurs near the apical foramen and significantly increases when the isthmus is located closer to the apical foramina.

Beyond skeletal studies: A computational analysis of nasal airway function in climate adaptation.

Ecogeographic variation in human nasal anatomy has historically been analyzed on skeletal morphology and interpreted in the context of climatic adaptations to respiratory air-conditioning. Only a few studies have analyzed nasal soft tissue morphology, actively involved in air-conditioning physiology. We used in vivo computer tomographic scans of (N = 146) adult individuals from Cambodia, Chile, Russia, and Spain. We conducted (N = 438) airflow simulations during inspiration using computational fluid dynamics to analyze the air-conditioning capacities of the nasal soft tissue in the inflow, functional, and outflow tract, under three different environmental conditions: cold-dry; hot-dry; and hot-humid. We performed statistical comparisons between populations and sexes. Subjects from hot-humid regions showed significantly lower air-conditioning capacities than subjects from colder regions in all the three conditions, specifically within the isthmus region in the inflow tract, and the anterior part of the internal functional tract. Posterior to the functional tract, no differences were detected. No differences between sexes were found in any of the tracts and under any of the conditions. Our statistical analyses support models of climatic adaptations of anterior nasal soft tissue morphology that fit with, and complement, previous research on dry skulls. However, our results challenge a morpho-functional model that attributes air-conditioning capacities exclusively to the functional tract located within the nasal cavity. Instead, our findings support studies that have suggested that both, the external nose and the intra-facial soft tissue airways contribute to efficiently warming and humidifying air during inspiration. This supports functional interpretations in modern midfacial variation and evolution.

Characterization of production units of cured foods in the Isthmus Region, Oaxaca, Mexico

Objective: To characterize the family production units (FPUs) that produce and market cured foods in the Isthmus Region. Design/methodology/approach: The approach was descriptive and correlational. The methodology used was proposed by Chayanov (1925), which proposes the assessment of six factors. A survey was applied and 75 variables were evaluated, Spearman’s correlation and chi-square test were carried out, and contingency tables were generated with the most significant variables. Results: With a higher the level of studies of the head of the family, the number of members was greater and women participated more in decision-making. The production of cured foods is a tradition inherited from one generation to another, and 73% learned the activity from a family member. The workforce is family-based and only family members are involved in 95% of the FPUs. Limitations on study/implications: The vastness of the region makes it difficult to cover other municipalities and insecurity makes it difficult to obtain information. Findings/conclusions: The family structure at the FPUs is nuclear. The woman directs the elaboration of cured foods, so it is considered that she plays an important role in conserving artisanal production.

Telocyte Recruitment During the Emergence of a Metaplastic Niche in the Stomach

Background & AimTelocytes, a recently identified type of sub-epithelial interstitial cell, have garnered attention for their potential roles in tissue homeostasis and repair. However, their contribution to gastric metaplasia remains unexplored. This study aimed to elucidate the role of telocytes in the development of metaplasia within the gastric environment. MethodsTo investigate the presence and behavior of telocytes during metaplastic transitions, we utilized both drug-induced acute injury models (using DMP-777 or L635) and a genetically engineered mouse model (Mist1-Kras). Lineage tracing via the Foxl1-CreERT2;R26R-tdTomato mouse model was used to track telocyte migratory dynamics. Immunofluorescence staining was used to identify telocyte markers and evaluate their correlation with metaplasia-related changes. ResultsWe confirmed the existence of FOXL1+/PDGFRα+ double-positive telocytes in the stomach's isthmus region. As metaplasia developed, we observed a marked increase in the telocyte population. The distribution of telocytes expanded beyond the isthmus to encompass the entire gland and closely reflected the expansion of the proliferative cell zone. Rather than a general response to mucosal damage, the shift in telocyte distribution was associated with the establishment of a metaplastic cell niche at the gland base. Furthermore, lineage-tracing experiments highlighted the active recruitment of telocytes to the emerging metaplastic cell niche, and we observed expression of Wnt5a, Bmp4, and Bmp7 in PDGFRα+ telocytes. ConclusionsThese results suggest that telocytes contribute to the evolution of a gastric metaplasia niche. The dynamic behavior of these stromal cells, their responsiveness to metaplastic changes, and potential association with Wnt5a, Bmp4, and Bmp7 signaling emphasize the significance of telocytes in tissue adaptation and repair.

Eradication of mature biofilm from the isthmus region using Er, Cr: YSGG Laser as an activator of 2% chlorhexidine gluconate.

Challenges in the root canal system, such as isthmus, may limit the action of endodontic equipment and irrigation solutions, so using laser agitation is recommended to upgrade the removal of microbial biofilm. The objective of this study is to assess the effectiveness of the laser in photon-induced photoacoustic streaming protocol agitation of 2% chlorohexidine gluconate in removing mature biofilm in complex root canal systems. Seventy-five mesial roots of the lower first and second molars were separated and cultivated with Enterococcus faecalis bacteria for 30 days (except for the negative control group samples). The samples were divided into four groups (n=15), one group acted as a positive control, other groups were irrigated with 2% chlorohexidine gluconate, some of them were agitated with a passive ultrasonic device, while the other samples were agitated by an Erbium, chromium-doped yttrium, scandium, gallium, and garnet laser in photon-induced photoacoustic streaming protocol. An atomic force microscope was used as a new method to get the results in the isthmus area; A scanning electron microscope was also used in the study to examine the samples before and after the treatment. Statistical Package for Social Sciences software was used to collect and analyze data, and two-way ANOVA was used to compare the means of the test groups. According to the atomic force microscope and scanning electron microscope analyses, Erbium laser and passive ultrasonic activation groups showed higher antimicrobial efficacy than the syringe irrigation group (p<0.05). According to the study's results, the agitation of chlorohexidine gluconate fluid by Erbium laser in photon-induced photoacoustic streaming at 0.75 W offers better Enterococcus faecalis biofilm removal in the difficult-to-reach areas of lower first and second molars. Key words:Atomic force microscope, 2% chlorhexidine gluconate, Enterococcus faecalis, Erbium, chromium-doped yttrium, scandium, gallium, garnet laser, passive ultrasonic.

Arch watch: current approaches and opportunities for improvement.

Coarctation of the aorta (CoA) is a ductus arteriosus (DA)-dependent form of congenital heart disease (CHD) characterized by narrowing in the region of the aortic isthmus. CoA is a challenging diagnosis to make prenatally and is the critical cardiac lesion most likely to go undetected on the pulse oximetry-based newborn critical CHD screen. When undetected CoA causes obstruction to blood flow, life-threatening cardiovascular collapse may result, with a high burden of morbidity and mortality. Hemodynamic monitoring practices during DA closure (known as an "arch watch") vary across institutions and existing tools are often insensitive to developing arch obstruction. Novel measures of tissue oxygenation and oxygen deprivation may improve sensitivity and specificity for identifying evolving hemodynamic compromise in the newborn with CoA. We explore the benefits and limitations of existing and new tools to monitor the physiological changes of the aorta as the DA closes in infants at risk of CoA.

Keratinocytes of the Upper Epidermis and Isthmus of Hair Follicles Express Hemoglobin mRNA and Protein.

The epidermis, the keratinized stratified squamous epithelium surrounding the body surface, offers a valuable framework to investigate how terrestrial animals overcome environmental stresses. However, the mechanisms underlying epidermal barrier function remain nebulous. In this study, we examined genes highly expressed in the human and mouse upper epidermis, the outer frontier that induces various barrier-related genes. Transcriptome analysis revealed that the messenger RNA level of hemoglobin α (HBA), an oxygen carrier in erythroid cells, was enriched in the upper epidermis compared with that in the whole epidermis. Immunostaining analysis confirmed HBA protein expression in human and mouse keratinocytes (KCs) of the stratum spinosum and stratum granulosum. HBA was also expressed in hair follicle KCs in the isthmus region; its expression levels were more prominent than those in interfollicular KCs. HBA expression was not observed in noncutaneous keratinized stratified squamous epithelia of mice, for example, the vagina, esophagus, and forestomach. HBA expression was upregulated in human epidermal KC cultures after UV irradiation, a major cause of skin-specific oxidative stress. Furthermore, HBA knockdown increased UV-induced production of ROS in primary KCs. Our findings suggest that epidermal HBA expression is induced by oxidative stress and acts as an antioxidant, contributing to skin barrier function.

Regional Arch Measurements Differ Between Imaging Modalities in Infants With Aortic Coarctation

BackgroundAortic arch measurements provide a framework for surgical decision-making in neonatal aortic coarctation, specifically in the determination of approach for arch repair by lateral thoracotomy vs median sternotomy. The purpose of this study was to evaluate our experience with transthoracic echocardiography (TTE) and computed tomography angiography (CTA) in the preoperative evaluation of infants with aortic coarctation, specifically comparing arch dimensions as a function of imaging modality. MethodsImaging data were reviewed for all infants undergoing surgical repair of aortic coarctation at our institution from 2012 to 2022. Infants with both TTE and CTA evaluations were included. Aortic measurements were compared at predefined anatomic regions including ascending aorta, proximal arch, distal arch, and isthmus. ResultsDuring the study period, 372 infants underwent surgical coarctation repair; 72 (19.4%) infants had TTE and CTA arch evaluations preoperatively. Significant discrepancies between imaging modalities were defined by poor correlation coefficients and absolute measurement differences and were most prominent in the proximal aortic arch (R2 = 0.23 [−4.4 to 3.2 mm]) and isthmus regions (R2 = 0.11 [−4.2 to 1.7 mm]). Improved correlation was demonstrated in the ascending aorta (R2 = 0.63) and distal aortic arch (R2 = 0.54). ConclusionsSignificant variability exists between TTE- and CTA-derived aortic measurements in infants with coarctation, with proximal arch measurements demonstrating the poorest correlation. This anatomic location represents a commonly used arch region for the determination of approach for repair of neonatal aortic coarctation. Thus, these findings have important implications for current preoperative surgical decision-making paradigms and future prospective study to minimize the risk of residual or recurrent arch obstruction.

Fallopian tube occlusion – anatomical ex vivo studies in advance of preclinical in vivo models for future microstent-based therapeutic concept evaluation

Abstract An unfulfilled pregnancy is often due to impaired patency of the female Fallopian tubes. To circumvent tubal obstruction, cost-intensive in vitro fertilisation (IVF) is currently indicated. The only therapeutic treatment concepts available are transvaginal tubal lavage/catheterization or laparoscopy with minimally invasive or complex surgical tubal reconstruction, which are associated with side effects. The development of new and cost-effective non- or minimally invasive therapeutic concepts that can restore the patency of the Fallopian tubes would be key in the treatment of female infertility and can fulfil the desire to have children. Therefore, in the present work, ex vivo anatomical studies are carried out on various laboratory mammals (pigs, rabbits, guinea pigs). Using these animal models, it was also evaluated whether a sensor-ureterorenoscope can be inserted through the whole female reproductive tract to the Fallopian tubes. This device will be used for endoscopically guided implantation of a novel tubal microstent prototype via its tailor-made delivery system into the isthmus region of the Fallopian tubes in upcoming studies. This work serves to identify an optimal species for a longitudinal animal study, in which the feasibility as well as the tissue reaction to the implant will be evaluated.

Identification of Human Ventricular Tachycardia Demarcated by Fixed Lines of Conduction Block in a 3-Dimensional Hyperboloid Circuit.

The circuit boundaries for reentrant ventricular tachycardia (VT) have been historically conceptualized within a 2-dimensional (2D) construct, with their fixed or functional nature unresolved. This study aimed to examine the correlation between localized lines of conduction block (LOBs) evident during baseline rhythm with lateral isthmus boundaries that 3-dimensionally constrain the VT isthmus as a hyperboloid structure. A total of 175 VT activation maps were correlated with isochronal late activation maps during baseline rhythm in 106 patients who underwent catheter ablation for scar-related VT from 3 centers (42% nonischemic cardiomyopathy). An overt LOB was defined by a deceleration zone with split potentials (≥20 ms isoelectric segment) during baseline rhythm. A novel application of pacing within deceleration zone (≥600 ms) was implemented to unmask a concealed LOB not evident during baseline rhythm. LOBs identified during baseline rhythm or pacing were correlated with isthmus boundaries during VT. Among 202 deceleration zones analyzed during baseline rhythm, an overt LOB was evident in 47%. When differential pacing was performed in 38 deceleration zones without overt LOBs, an underlying concealed LOB was exposed in 84%. In 152 VT activation maps (2D=53, 3-dimensional [3D]=99), 69% of lateral boundaries colocalized with an LOB in 2D activation patterns, and the depth boundary during 3D VT colocalized with an LOB in 79%. In VT circuits with isthmus regions that colocalized with a U-shaped LOB (n=28), the boundary invariably served as both lateral boundaries in 2D and 3D. Overall, 74% of isthmus boundaries were identifiable as fixed LOBs during baseline rhythm or differential pacing. The majority of VT circuit boundaries can be identified as fixed LOBs from intrinsic or paced activation during sinus rhythm. Analysis of activation while pacing within the scar substrate is a novel technique that may unmask concealed LOBs, previously interpreted to be functional in nature. An LOB from the perspective of a myocardial surface is frequently associated with intramural conduction, supporting the existence of a 3D hyperboloid VT circuit structure. Catheter ablation may be simplified to targeting both sides around an identified LOB during sinus rhythm.

The efficacy of a novel SWEEPS laser-activated irrigation compared to ultrasonic activation in the removal of pulp tissue from an isthmus area in the apical third of the root canal.

This study aimed to evaluate the efficacy of Shock Wave Enhanced Emission Photoacoustic Streaming (SWEEPS) in the removal of remaining pulp tissue from the root canal isthmus area in lower molars and compare it with ultrasonically activated irrigation (UAI) and conventional needle irrigation (NI). Forty-one lower molars with isthmuses between mesial canals were included in the study. The teeth were randomly distributed into experimental groups (n = 12/each) based on the final irrigation protocol (SWEEPS, UAI, or NI) and a control group (C) (n = 5). The traditional access cavity of the mesial part of each tooth was made in all samples. The mesial root canals in the experimental groups were instrumented with a Wave One Gold Primary (25/.07) file using 3% sodium hypochlorite (NaOCl) while the distal canal served as a control for the presence of pulp tissue. No treatment was performed in the C group. Sections from the isthmus region were processed for histopathology to measure the remaining pulp tissue (RPT). The results were analyzed using analysis of variance and the Kruskal-Wallis test (α = 0.05). There were no significant differences in the relative surface area of root canals and isthmus among the groups (p > 0.05). Samples in the SWEEPS group had significantly less RPT than UAI, NI, and C (p = 0.003, 0.014, 0.003, respectively). There were no significant differences between the UAI and NI (p = 0.583). SWEEPS was the most efficient in debridement of the root canal isthmus area. UAI and NI showed similar but lower efficiency.

P-348 Correlation between cesarean scar defect and chronic endometritis and its effect on the pregnancy outcomes of in vitro fertilization

Abstract Study question Do patients with symptomatic cesarean scar defect (CSD) have a higher risk of chronic endometritis (CE) and worse early pregnancy outcomes after hysteroscopic reconstruction for CSD? Summary answer Symptomatic CSD has a positive correlation with CE. Antibiotic administration is a promising option for patients with CE to obtain better early pregnancy outcomes. What is known already Cesarean scar defect (CSD), a niche-shaped myometrium defect, can be noticed after cesarean sections (CS). Studies about the impact of CSD on fertility are limited. The uterine isthmic region is a sperm reservoir, and CSD may negatively affect natural fertility. CE could reduce endometrial receptivity and thus leads to a lower clinical pregnancy rate. Secondary infertile patients with a history of CS are quite common in the department of reproductive medicine. However, there was still limited data to determine whether CSD correlates with CE, especially in cases suffering from symptomatic CSD with postmenstrual spotting. Study design, size, duration This is a retrospective study including 118 patients with a leading symptom of postmenstrual spotting and 224 asymptomatic patients from January 1, 2018 to May 31, 2021. Participants/materials, setting, methods Group A was with a leading symptom of postmenstrual spotting, and group B was asymptomatic. Office operative hysteroscopy was performed to correct the CSD for symptomatic patients in group A, and thermoablation of the endometrium in CSD was performed. Out-patient hysteroscopy was performed for asymptomatic patients in group B, and only the morphology of the endometrium was evaluated. Both groups have CD138 immunohistochemistry staining of their endometrium. Main results and the role of chance A higher incidence of CE was found in group A compared with group B (50/118 vs. 62/224, P=0.006, OR = 1.921, 95%CI=1.203-3.068). There were no significant differences in the comparisons of chemical pregnancy rate (26/86 vs. 75/216, P=0.455, OR = 0.815, 95%CI=0.475-1.396), ectopic pregnancy rate (1/86 vs. 1/216, P=0.489, OR = 2.529, 95%CI=0.156-40.901), miscarriage rate (6/86 vs. 22/216, P=0.368, OR = 0.661, 95%CI=0.258-1.692), preterm birth rate (2/86 vs. 4/216, P=1.000, OR = 1.262, 95%CI=0.227-7.020) or full-term pregnancy rate (12/86 vs. 35/216, P=0.626, OR = 0.839, 95%CI=0.413-1.704) between the two groups. Limitations, reasons for caution First, different doctors might have inconsistent judgments on the definition of postmenstrual spotting. Second, three different operators performed the hysteroscopy. It might contribute to the heterogeneity of the study findings. Wider implications of the findings Canalling and thermoablation during hysteroscopy are effective treatments for symptomatic CSD. CSD accompanied by CE should be given more attention before embryo transfer. Trial registration number No. 2020A1515110791