Primary Defect Research Articles

Fascia defect closure versus non-closure in minimal invasive direct inguinal hernia mesh repair: a systematic review and meta-analysis of real-world evidence.

Laparoscopic and robotic inguinal hernia mesh repair are both common surgical procedures worldwide. Postoperative hernia recurrence and seroma formation are important concerns. In ventral hernia, primary defect closure in laparoscopic surgery reduces the recurrence rate. However, there is no synthetic evidence of direct inguinal hernia defect closure versus non-closure in minimal invasive surgery. Therefore, this study investigated the efficacy of defect closure in patients undergoing minimal invasive direct inguinal hernia mesh repair. Eligible studies were identified through a search of PubMed, Embase, Cochrane Library, and CINAHL from their inception until March 2022. Studies examining defect closure in laparoscopic direct inguinal hernia repair were included, and a meta-analysis was performed using the random-effect model. Sensitivity analyses were performed by removing one study at a time. The primary outcomes were hernia recurrence and seroma formation. Acute and chronic postoperative pain, operation time, and length of hospital stay were the secondary outcomes. Five nonrandomized studies and one randomized controlled trial were included. Pooled analysis revealed defect closure might reduce the hernia recurrence rate (risk difference, -0.02; 95% confidence interval [CI] -0.04 to -0.00; p = 0.02). The result of seroma formation (odds ratio, 0.49; 95% CI 0.17-1.46; p = 0.20) showed no significant difference. Moreover, no significant differences were observed in acute postoperative pain, chronic pain, length of hospital stay, and operation time. Our study indicated defect closure seems to be an option to reduce the direct inguinal hernia recurrence rate. No significant benefits were shown in seroma formation and other secondary outcomes. Our study was mostly based on nonrandomized studies and underestimated the effect of defect closure; thus, further high-quality studies are required to draw definitive conclusions.

Literary Racial Impersonation

Literary racial impersonation occurs when a narrative work fails to express the perspective of a minority ethnic or racial group. Interestingly, even when these works express moral themes congenial to promoting empathetic responses towards these groups, they can be met with public outrage if the group’s perspective is portrayed inaccurately. My goal in this paper is to vindicate the intuition that failure to express the perspective of a minority group well renders the work defective, both aesthetically and morally. I argue that available frameworks exploring the connections between aesthetic and moral realms of value are inadequate to analyzing this phenomenon and propose a novel connection between aesthetic and moral values. Specifically, I demonstrate that the primary defect of literary racial impersonation is aesthetic and contingently constitutes a moral defect in our current social context.

Endothelial dysfunction: developmental mechanisms and therapeutic strategies

Introduction: Every year the importance of the normal functioning of the endothelial layer of the vascular wall in maintaining the health of the body becomes more and more obvious.
 The physiological role of the endothelium: The endothelium is a metabolically active organ actively involved in the regulation of hemostasis, modulation of inflammation, maintenance of hemovascular homeostasis, regulation of angio­genesis, vascular tone, and permeability.
 Risk factors for the development of endothelial dysfunction: Currently, insufficient bioavailability of nitric oxide is considered the most significant risk factor for endothelial dysfunction.
 Mechanisms of development of endothelial dysfunction: The genesis of endothelial dysfunction is a multifactorial process. Among various complex mechanisms, this review examines oxidative stress, inflammation, hyperglycemia, vitamin D deficiency, dyslipidemia, excess visceral fat, hyperhomocysteinemia, hyperuricemia, as well as primary genetic defect of endotheliocytes, as the most common causes in the population underlying the development of endo­thelial dysfunction.
 Markers of endothelial dysfunction in various diseases: This article discusses the main biomarkers of endothelial dysfunction currently used, as well as promising biomarkers in the future for laboratory diagnosis of this pathology.
 Therapeutic strategies: Therapeutic approaches to the endothelium in order to prevent or reduce a degree of damage to the vascular wall are briefly described.
 Conclusion: Endothelial dysfunction is a typical pathological process involved in the pathogenesis of many diseases. Thus, pharmacological agents with endothelioprotective properties can provide more therapeutic benefits than a drug without such an effect.

Organoid Technology and Its Role for Theratyping Applications in Cystic Fibrosis.

Cystic fibrosis (CF) is a autosomal recessive, multisystemic disease caused by different mutations in the CFTR gene encoding CF transmembrane conductance regulator. Although symptom management is important to avoid complications, the approval of CFTR modulator drugs in the clinic has demonstrated significant improvements by targeting the primary molecular defect of CF and thereby preventing problems related to CFTR deficiency or dysfunction. CFTR modulator therapies have positively changed the patients' quality of life, especially for those who start their use at the onset of the disease. Due to early diagnosis with the implementation of newborn screening programs and considerable progress in the treatment options, nowadays pediatric mortality was dramatically reduced. In any case, the main obstacle to treat CF is to predict the drug response of patients due to genetic complexity and heterogeneity. Advances in 3D culture systems have led to the extrapolation of disease modeling and individual drug response in vitro by producing mini organs called "organoids" easily obtained from nasal and rectal mucosa biopsies. In this review, we focus primarily on patient-derived intestinal organoids used as in vitro model for CF disease. Organoids combine high-validity of outcomes with a high throughput, thus enabling CF disease classification, drug development and treatment optimization in a personalized manner.

Evaluating the Potential of Lead‐Free Nontoxic Cs2BiAgI6‐Based Double Perovskite Solar Cell

Recently, the efficiency of single‐junction perovskite solar cells has been competing with the crystalline Si solar cells. However, the perovskite absorbers are toxic and susceptible to moisture. Herein, the performance of an environmentally benign and durable Cs2BiAgI6 light harvester using the 1D Solar Cell Capacitance Simulator (SCAPS‐1D) software package is evaluated. The primary physical parameters, namely, defect and doping densities and thickness of the subsequent layers, are varied to achieve high efficiencies. The optimized Cs2BiAgI6‐based double perovskite solar cells with three distinct hole‐transporting layers (HTLs) (i.e., MoO3, CuSCN, and spiro‐OMeTAD) deliver a power conversion efficiency of ≈29% with AZnO as electron transport layer (ETL). Further, a variety of possible rear electrodes are explored, and their effect on the performance is estimated. For real‐time examination of the Cs2BiAgI6‐based double perovskite solar cells, the variation of power conversion efficiency (PCE) concerning the operating temperature is estimated. The thickness of the Cs2BiAgI6 light harvester layer and the bulk defect density are the key aspects in attaining high power conversion efficiencies in Cs2BiAgI6‐based double perovskite solar cells.

Orthostatic Intolerance after COVID-19 Infection: Is Disturbed Microcirculation of the Vasa Vasorum of Capacitance Vessels the Primary Defect?

Following COVID-19 infection, a substantial proportion of patients suffer from persistent symptoms known as Long COVID. Among the main symptoms are fatigue, cognitive dysfunction, muscle weakness and orthostatic intolerance (OI). These symptoms also occur in myalgic encephalomyelitis/chronic fatigue (ME/CFS). OI is highly prevalent in ME/CFS and develops early during or after acute COVID-19 infection. The causes for OI are unknown and autonomic dysfunction is hypothetically assumed to be the primary cause, presumably as a consequence of neuroinflammation. Here, we propose an alternative, primary vascular mechanism as the underlying cause of OI in Long COVID. We assume that the capacitance vessel system, which plays a key role in physiologic orthostatic regulation, becomes dysfunctional due to a disturbance of the microvessels and the vasa vasorum, which supply large parts of the wall of those large vessels. We assume that the known microcirculatory disturbance found after COVID-19 infection, resulting from endothelial dysfunction, microthrombus formation and rheological disturbances of blood cells (altered deformability), also affects the vasa vasorum to impair the function of the capacitance vessels. In an attempt to compensate for the vascular deficit, sympathetic activity overshoots to further worsen OI, resulting in a vicious circle that maintains OI. The resulting orthostatic stress, in turn, plays a key role in autonomic dysfunction and the pathophysiology of ME/CFS.

BPA exposure in L6 myotubes increased basal glucose metabolism in an estrogen receptor-dependent manner but induced insulin resistance

Exposure to bisphenol A (BPA) is associated with insulin resistance and type 2 diabetes (T2D). Since muscle insulin resistance is the primary defect in T2D, we aimed to determine whether BPA alters glucose metabolism in L6 muscle cells. L6 or L6-GLUT4-myc cells were exposed to 1-104 nM BPA or the vehicle (0.1% DMSO) for 7 days. BPA at 103-104 nM significantly decreased the levels of the muscle differentiation markers troponin- T and myosin heavy chain 3. Insulin-stimulated phosphorylation of Akt and GSK3, insulin-stimulated glucose uptake, and insulin-stimulated GLUT4 translocation were significantly decreased with 103-104 nM BPA. Basal glucose uptake and glycolysis (extracellular acidification rates measured by Seahorse XFe96) were increased with 103-104 nM BPA. Levels of ROS detoxifying enzymes were increased with BPA >10nM, while catalase activity was increased with 103-104 nM BPA. However, BPA did not induce oxidative stress (measured by protein carbonylation and lipid peroxidation) nor mitochondrial dysfunction. The effects of BPA on basal glucose uptake and catalase activity, but not on insulin sensitivity, were restored when estrogen receptors (ERs) were inhibited with ICI. These findings suggest that high concentrations of BPA increase muscle glucose uptake through the ERs but induce insulin resistance through another pathway.

Surgical treatment of achalasia: results and quality of life

Abstract Achalasia is a primary defect of esophageal motility of unknown aetiology, characterised by peristaltic dysfunction of the esophagus and impaired relaxation of the lower esophageal sphincter. The most common symptoms are dysphagia, regurgitation, weight loss, and chest burning. There are various treatment options for achalasia: botulinum toxin injections, pneumatic dilatation, Heller myotomy, and peroral endoscopic myotomy. The aim of the study was to access the efficacy and quality of life of patients with achalasia after surgical treatment — laparoscopic Heller myotomy and Dor fundoplication. All of the patients after surgery had a high gastrointestinal quality of life index. For all patients, during the follow-up period (median 2.4 years), the intensity of clinical symptoms after the procedure declined. Laparoscopic Heller myotomy with Dor fundoplication is a safe and effective method of treating achalasia and can reduce clinical symptoms and improve patients' quality of life.

Evidence of redox imbalance and mitochondrial dysfunction in Niemann-Pick type C 1 patients: thein vitro effect of combined therapy with antioxidants and β-cyclodextrin nanoparticles.

Niemann-Pick C disease (NPC) is an autosomal recessive genetic disorder resulting from mutation in one of two cholesterol transport genes: NPC1 or NPC2, causing accumulation of unesterified cholesterol, together with glycosphingolipids, within the endosomal/lysosomal compartment of cells. The result is a severe disease in both multiple peripheral organs and the central nervous system, causing neurodegeneration and early death. However, the pathophysiological mechanisms of NPC1 remain poorly understood. Recent studies have shown that the primary lysosomal defect found in fibroblasts from NPC1 patients is accompanied by a deregulation of mitochondrial organization and function. There is currently no cure for NPC1, but recently the potential of β-cyclodextrin (β-CD) for the treatment of the disease was discovered, which resulted in the redistribution of cholesterol from subcellular compartments to the circulation and increased longevity in an animal model of NPC1. Considering the above, the present work evaluated the in vitro therapeutic potential of β-CD to reduce cholesterol in fibroblasts from NPC1 patients. β-CD was used in its free and nanoparticulate form. We also evaluated the β-CD potential to restore mitochondrial functions, as well as the beneficial combined effects of treatment with antioxidants N-Acetylcysteine (NAC) and Coenzyme Q10 (CoQ10). Besides, we evaluated oxidative and nitrative stress parameters in NPC1 patients. We showed that oxidative and nitrative stress could contribute to the pathophysiology of NPC1, as the levels of lipoperoxidation and the nitrite and nitrate levels were increased in these patients when compared to healthy individuals, as well as DNA damage. The nanoparticles containing β-CD reduced the cholesterol accumulated in the NPC1 fibroblasts. This result was potentiated by the concomitant use of the nanoparticles with the antioxidants NAC and CoQ10 compared to those presented by healthy individuals cells ́. In addition, treatments combining β-CD nanoparticles and antioxidants could reduce mitochondrial oxidative stress, demonstrating advantages compared to free β-CD. The results obtained are promising regarding the combined use of β-CD loaded nanoparticles and antioxidants in the treatment of NPC1 disease.

Photoreceptor function and structure in retinal degenerations caused by biallelic BEST1 mutations

The only approved retinal gene therapy is for biallelic RPE65 mutations which cause a recessive retinopathy with a primary molecular defect located at the retinal pigment epithelium (RPE). For a distinct recessive RPE disease caused by biallelic BEST1 mutations, a pre-clinical proof-of-concept for gene therapy has been demonstrated in canine eyes. The current study was undertaken to consider potential outcome measures for a BEST1 clinical trial in patients demonstrating a classic autosomal recessive bestrophinopathy (ARB) phenotype. Spatial distribution of retinal structure showed a wide expanse of abnormalities including large intraretinal cysts, shallow serous retinal detachments, abnormalities of inner and outer segments, and an unusual prominence of the external limiting membrane. Surrounding the central macula extending from 7 to 30 deg eccentricity, outer nuclear layer was thicker than expected from a cone only retina and implied survival of many rod photoreceptors. Co-localized however, were large losses of rod sensitivity despite preserved cone sensitivities. The dissociation of rod function from rod structure observed, supports a large treatment potential in the paramacular region for biallelic bestrophinopathies.

Novel red-emitting orthorhombic GdInO3:Eu3+ perovskite phosphor: Structural resolution, Judd-Ofelt theory, and comparative investigation with hexagonal counterpart

A novel orthorhombic GdInO3:Eu perovskite red phosphor, endowed with good luminescence properties, was synthesized via a facile co-precipitation route plus controllable thermolysis. Its structural features, optical properties, and luminescent behaviors were compared with the hexagonal counterpart in detail. The two GdInO3 matrixes have relatively wide direct bandgaps (∼5.07 eV for orthorhombic perovskite and ∼5.13 eV for hexagonal phase) and low phonon energies (∼368 cm−1 for orthorhombic perovskite and ∼425 cm−1 for hexagonal contrast). Eu3+ substitution for Gd3+ occupies the C2v symmetry site without an inversion center in orthorhombic GdInO3, while the hexagonal GdInO3 provides two crystallographic positions for Eu3+ residence (∼2/3 at C3 site and ∼1/3 at C6v site). The emission spectra of two phosphors present characteristic 5D0→7FJ transitions of Eu3+ and the optimum activator concentrations are both 10 at.%. They also have good thermal stability of luminescence with relatively high similar activation energies of ∼0.25 eV. F+ center (VO∙ oxygen vacancy) is the primary defect form in the two perovskites, which has little effect on the entire red emission of orthorhombic phosphor but shifts the chromaticity coordinate of hexagonal contrast toward orange region. The orthorhombic GdInO3:Eu phosphor exhibits stronger emission intensity, a longer fluorescence lifetime, and a higher color purity than the hexagonal counterpart. Judd–Ofelt theory further confirms that orthorhombic GdInO3:Eu is an efficient red-emitting material with the relatively large parameters of Ω2 = 7.01 × 10–20 cm–2 and Ω4 = 2.85 × 10–20 cm–2.

Effect of yoga intervention on skeletal muscle linked glucose homeostasis in pre-diabetic individuals: Study protocol for a randomized controlled trial

BackgroundThe pre-diabetic stage is important in terms of identification and timely management due to its reversible nature. Along with other factors, insulin resistance in skeletal muscle is often considered as primary defect before development of overt hyperglycemia and Diabetes Mellitus (DM). Physical exercises are beneficial in prevention of DM by improving skeletal muscle mediated glucose metabolism. Evidence suggests that Yoga interventions appear to be equal and/or superior to exercise in most outcome measures. As the Yogic postures are relatable to exercises, they are considered to improve skeletal muscle function and reverse the pre-diabetic stage. MethodsThis open-labelled, randomized clinical study is planned to evaluate effect of Yoga interventions on muscle mass, strength, endurance and flexibility which are direct/indirect indicators of fat deposition in skeletal muscles. Association between changes in muscle quality/ functionality and glycemic control will also be explored. With ethics committee permission, 120 pre-diabetic individuals of either sex between age group of 35–49 years with BMI range of 25–35 kg/m2 and family history of Type 2 Diabetes Mellitus (T2DM) will be recruited after obtaining written informed consent. They will be randomly allocated to either Yoga or exercise group by computer generated randomized method in a 1:1 ratio. One group will receive defined Yoga interventions, while other group will receive fixed program of physical exercises. Prior to initiating this 12-week study, both groups will undergo a training session for 4 weeks under supervision of a trained instructor. The outcome measures will be parameters related to muscle quality/functionality and glucose metabolism markers. DiscussionOur study aims to explore practicality of Yoga in pre-diabetic stage on skeletal muscle related glycemic control, which is novel. Additionally, the study will generate awareness about pre-diabetes and provide people with active coping skills for reversing it.

OR04-2 WNT2B Deficiency Results in Hyperreninemic Hypoaldosteronism in Humans and Mice

Abstract Proper development and zonation of the adrenal cortex is intimately connected with its lifelong capacity to produce steroid hormones. Both adrenocortical development and homeostasis are mediated in part by paracrine WNT/β-catenin signaling, an essential pathway for zonal maintenance and aldosterone production. Patients harboring homozygous or compound heterozygous loss-of-function (LOF) mutations in the WNT ligand WNT2B present with congenital diarrhea and require parenteral nutrition. Despite evidence for euvolemia, WNT2B-null patients exhibit markedly elevated plasma renin levels with no corresponding increase in aldosterone, suggesting a primary adrenal defect in aldosterone synthesis. To test this hypothesis, we generated both global and conditional Wnt2b knockout mouse models. In the mouse adrenal, Wnt2b is expressed exclusively in the capsule, the outer compartment of mesenchymal cells that overlay and signal to the subcapsular zona glomerulosa (zG), the adrenocortical zone that harbors aldosterone-producing cells and critical long-term progenitor cells. Global loss of Wnt2b from early mouse development results in a near-complete absence of the histological zG. Moreover, Wnt2b-null mice exhibit significantly increased plasma renin but normal aldosterone levels compared to wild-type controls. These data suggest that WNT2B-null patients indeed have an adrenocortical phenotype caused by apparent zG hypofunction. To further define the mechanism(s) by which Wnt2b LOF leads to zG hypofunction, we temporally deleted Wnt2b in the adrenal capsule of adult mice. Wnt2b conditional knockout (cKO) adrenals exhibit a zG-restricted decrease in Wnt/β-catenin signaling as determined by decreased β-catenin activity and target gene expression. Moreover, Wnt2b cKO mice demonstrated a disorganized zG and disrupted adrenocortical zonation. To determine the contribution of WNT2B to aldosterone production, we administered a sodium-deficient diet to control and Wnt2b cKO mice to activate the renin-angiotensin-aldosterone system. Indeed, while control mice exhibited the expected increase in both plasma renin and aldosterone, Wnt2b cKO mice showed marked elevation of renin despite normal aldosterone compared to controls, consistent with hyperreninemic hypoaldosteronism. Together, our work supports a WNT2B-dependent mechanism for adrenal zG development and maintenance in mice and humans and provides relevant models to study the consequences of WNT2B deficiency within the zG. Presentation: Saturday, June 11, 2022 11:45 a.m. - 12:00 p.m.

Depleted Calcium Stores and Increased Calcium Entry in Rod Photoreceptors of the Cacna2d4 Mouse Model of Cone-Rod Dystrophy RCD4.

Unidentified pathogenetic mechanisms and genetic and clinical heterogeneity represent critical factors hindering the development of treatments for inherited retinal dystrophies. Frameshift mutations in Cacna2d4, which codes for an accessory subunit of voltage-gated calcium channels (VGCC), cause cone-rod dystrophy RCD4 in patients, but the underlying mechanisms remain unknown. To define its pathogenetic mechanisms, we investigated the impact of a Cacna2d4 frameshift mutation on the electrophysiological profile and calcium handling of mouse rod photoreceptors by patch-clamp recordings and calcium imaging, respectively. In mutant (MUT) rods, the dysregulation of calcium handling extends beyond the reduction in calcium entry through VGCC and surprisingly involves internal calcium stores' depletion and upregulation of calcium entry via non-selective cationic channels (CSC). The similar dependence of CSC on basal calcium levels in WT and MUT rods suggests that the primary defect in MUT rods lies in defective calcium stores. Calcium stores' depletion, leading to upregulated calcium and sodium influx via CSC, represents a novel and, so far, unsuspected consequence of the Cacna2d4 mutation. Blocking CSC may provide a novel strategy to counteract the well-known pathogenetic mechanisms involved in rod demise, such as the reticulum stress response and calcium and sodium overload due to store depletion.

The novel visual cycle inhibitor (±)-RPE65-61 protects retinal photoreceptors from light-induced degeneration.

The visual cycle refers to a series of biochemical reactions of retinoids in ocular tissues and supports the vision in vertebrates. The visual cycle regenerates visual pigments chromophore, 11-cis-retinal, and eliminates its toxic byproducts from the retina, supporting visual function and retinal neuron survival. Unfortunately, during the visual cycle, when 11-cis-retinal is being regenerated in the retina, toxic byproducts, such as all-trans-retinal and bis-retinoid is N-retinylidene-N-retinylethanolamine (A2E), are produced, which are proposed to contribute to the pathogenesis of the dry form of age-related macular degeneration (AMD). The primary biochemical defect in Stargardt disease (STGD1) is the accelerated synthesis of cytotoxic lipofuscin bisretinoids, such as A2E, in the retinal pigment epithelium (RPE) due to mutations in the ABCA4 gene. To prevent all-trans-retinal—and bisretinoid-mediated retinal degeneration, slowing down the retinoid flow by modulating the visual cycle with a small molecule has been proposed as a therapeutic strategy. The present study describes RPE65-61, a novel, non-retinoid compound, as an inhibitor of RPE65 (a key enzyme in the visual cycle), intended to modulate the excessive activity of the visual cycle to protect the retina from harm degenerative diseases. Our data demonstrated that (±)-RPE65-61 selectively inhibited retinoid isomerase activity of RPE65, with an IC50 of 80 nM. Furthermore, (±)-RPE65-61 inhibited RPE65 via an uncompetitive mechanism. Systemic administration of (±)-RPE65-61 in mice resulted in slower chromophore regeneration after light bleach, confirming in vivo target engagement and visual cycle modulation. Concomitant protection of the mouse retina from high-intensity light damage was also observed. Furthermore, RPE65-61 down-regulated the cyclic GMP-AMP synthase stimulator of interferon genes (cGAS-STING) pathway, decreased the inflammatory factor, and attenuated retinal apoptosis caused by light-induced retinal damage (LIRD), which led to the preservation of the retinal function. Taken together, (±)-RPE65-61 is a potent visual cycle modulator that may provide a neuroprotective therapeutic benefit for patients with STGD and AMD.

OC-020 INCISIONAL HERNIA REPAIR WITH MESH REIMAGINED: PILOT STUDY USING ABDOMINOPLASTY AS PERMANENT AUTOLOGOUS BIOLOGICAL REINFORCEMENT IN HERNIA REPAIR

Abstract Aim EHS consensus recommends mesh implantation for all incisional hernia (IH) repairs, regardless of size. We propose considering abdominoplasty in the algorithm for IH repairs wherein the plicated fascia functions as a permanent autologous biologic onlay repair over the primary repair of the IH. Materials & Methods Four patients with midline IHs underwent abdominoplasty. Their IHs were first closed primarily with #2–0 permanent suture. Next, a two-layer anterior plication of the overlying fascia was performed with permanent suture. No mesh was implanted. Patients were followed up post operatively to monitor for hernia recurrence. Results All patients were female with average age 51 years. All had at least one midline IH (1cm-1.7cm wide). Three (75%) had recurrent IHs. Three (75%) had diastasis recti. Patients were followed at 1 year, with no (0%) recurrence. Conclusion Abdominoplasty may be a safe and effective alternative for IH repair compared to traditional mesh-based repair. In effect, the patient's own plicated fascia functions as a permanent autologous biologic onlay reinforcement to the IH repair. Meanwhile, the plication may reduce tension off the primary defect closure, thus reducing recurrence. Our pilot study in small IHs showed no hernia recurrence one-year postoperatively after abdominoplasty. Thus, abdominoplasty may serve as an alternative surgical option to a subset of patients with IH. We aim to judiciously expand indications for abdominoplasty for IH repair to address wider defects in select candidates. We hope our experience will supplement the current algorithm for IH repairs by providing a non-mesh alternative.

(Invited) Prussian Blue Analogues as Battery Materials

Prussian Blue Analogues (PBAs) have gathered renewed interest recently because of their unique electrochemical properties, several of which are highly desirable for energy storage1. These intriguing properties arise from the interaction of the crystal structure with inserting ions. The general electrochemical equation for the insertion of an alkali metal into a PBA is given by:AxPJ[RK(CN)6]1−y · wH2O + A+ + e− → Ax+1PJ[RK−1(CN)6]1−y · wH2Owhere A is an alkali-metal ion, and P and R are transition-metal ions octahedrally coordinated to six cyanide ligands via the nitrogen and carbon atom, respectively (Figure 1). The value y is the fraction of vacancies in the hexacyanoferrate complex ion (the primary lattice defect). Water can also be present, both as zeolitic and coordinated to deficiently bonded metal ions at vacancies. Figure 1: Schematic representation of the crystal structure of PBAs. The green and dark-blue atoms are transition-metal ions at the R site and P site, respectively. Gray atoms are carbon and light-blue atoms are nitrogen. In my talk, I will show how these exciting properties are linked to the structural diversity of PBAs2 and how their chemistry can be tuned to adapt their electrochemistry to a variety of energy storage applications3,4, with focus on K-ion batteries5–7. References Hurlbutt, K., Wheeler, S., Capone, I. & Pasta, M. Prussian Blue Analogs as Battery Materials. Joule vol. 2 1950–1960 (2018).Cattermull, J., Pasta, M. & Goodwin, A. L. Structural complexity in Prussian blue analogues. Materials Horizons 8, 3178–3186 (2021).Wheeler, S., Capone, I., Day, S., Tang, C. & Pasta, M. Low-Potential Prussian Blue Analogues for Sodium-Ion Batteries: Manganese Hexacyanochromate. Chemistry of Materials 31, 2619–2626 (2019).Hurlbutt, K., Giustino, F., Pasta, M. & Volonakis, G. Electronic Structure and Electron-Transport Properties of Three Metal Hexacyanoferrates. Chemistry of Materials 33, 7067–7074 (2021).Fiore, M. et al. Paving the Way toward Highly Efficient, High-Energy Potassium-Ion Batteries with Ionic Liquid Electrolytes. Chemistry of Materials 32, 7653–7661 (2020).Dhir, S., Wheeler, S., Capone, I. & Pasta, M. Outlook on K-Ion Batteries. Chem 6, 2442–2460 (2020).Cattermull, J. et al. Revealing the structural complexity of Prussian blue analogues: the case of K2Cu[Fe(CN)6]. ChemRxiv (2022) doi:10.26434/chemrxiv-2022-zr5nn. Figure 1

VP.79 Challenges in genetic diagnosis of LAMA2-MD - when the pieces do not fit

Pathogenic variants in the <i>LAMA2</i> gene can cause muscular dystrophy (MD) associated with variable degrees of severity. We describe an infant with a congenital phenotype: severe hypotonia and weakness at birth, elevated creatine kinase levels, brain white-matter alterations and reduced merosin expression in muscle biopsy. Next-generation sequencing (NGS) targeting a panel of genes involved in hereditary myopathies revealed a rare homozygous missense variant in exon 39 of the <i>LAMA2</i> gene. Detailed genotype-phenotype evaluation associated with an incongruent bioinformatics analysis led us to proceed to full <i>LAMA2</i> cDNA analysis. A partial retention of intron 14 was identified, thought to be the primary genetic defect accountable for the patient´s phenotype. Further investigation enabled us to conclude that this splicing event was instigated by the presence of a homozygous intronic substitution located 117bp downstream of exon 14, which created a cryptic splice site. To our knowledge, this splicing variant represents the first pathogenic variant located further from the <i>LAMA2</i> exon-intron boundaries. Besides the importance of cDNA studies, this work highlights the need for critical judgment of any identified variants of unknown significance (VUS) in the definition of the correct and causal genotype.

VP.83 Ion channels and myogenesis in Duchenne muscular dystrophy: Electrophysiological profile of wild-type and dystrophic myoblasts and myocytes

In skeletal muscle, several ion channels interact with the dystrophin complex, which is disrupted in Duchenne muscular dystrophy (DMD). However, little is known about their involvement in myogenesis in DMD. Here, we performed a pilot study to characterize the electrophysiological asset of myoblasts and myocytes at day 2/4/6/11 by using two immortalized mouse satellite-derived cell lines: the wild-type 2B4 and the dystrophic SF1. We evaluated both inward and outward currents at different time points of differentiation by whole-cell patch clamp. 2B4 cells showed an increment of inward currents as the differentiation program progresses. In SF1 myocytes, inward currents increased up to the 6th day of differentiation, like in 2B4 cells. However, day-11 SF1 myocytes showed 50% lower inward currents compared to day-11 2B4 myocytes (5.2 nA vs 2.8 nA at -20 mV). High concentration of tetrodotoxin blocked these inward currents in both day-6 and day-11 2B4/SF1. Outward currents were clearly detectable in day-11 2B4 cells but very small in day-2/4/6 2B4 cells. Conversely, SF1 outward currents reached the highest value at day-6, being 3-fold higher than 6-day 2B4 cells (733 pA vs 283 pA at +60 mV). However, day-11 SF1 myocytes showed 44% lower outward currents, compared to day-11 2B4 cells (722 pA vs 1283 pA). BaCl₂ decreased outward currents in day-6 2B4/SF1 cells and in day-11 2B4 myocytes. In addition, we assessed resting membrane potentials which became more negative as the days of differentiation increased in both cell-lines. However, day-11 SF1 cells had a more depolarised membrane potential, compared to day-11 2B4 myocytes. This preliminary data suggests that during myogenesis, intrinsic impairments in ion channel development are disclosed by dystrophic conditions, likely in relation to the primary defect. Furthermore, electrophysiological characterization of human wild-type and dystrophic myoblasts/myocytes is on-going.

Sirenomelia

Sirenomelia is a rare and fatal congenital defect characterized by varying degrees of lower limb fusion, thoracolumbar spinal anomalies, sacrococcygeal agenesis, genitourinary, and anorectal atresia.There is a strong association with maternal diabetes where relative risk is 1:200-250 and up to 22% of fetuses with this anomaly will have mothers with diabetes.A 34-year-old unbooked G3P2L2 at 35 weeks 5 days of gestational age with previous two live vaginal birth was admitted in the labor room with pain in the abdomen. She had no history of prior antenatal care and belonged to a tribal community with lower socioeconomic status.She was otherwise healthy with no known history of genetic or congenital anomaly in her family. Baby not cried after birth , no activity and hypotonia present . Immediately intubated with ET NO 3 and bag and tube ventilation given and shifted to NICU and put on ACMV mode of ventilationAnomalies observed in sirenomelia are described as the most severe form of caudal regression syndrome. Fusion of the lower extremities, presence of single umbilical and persistent vitelline artery are major features of sirenomelia . Although the primary molecular defect resulting in sirenomelia remains unclear, two main pathogenic hypotheses namely the vascular steal hypothesis and the defective blastogenesis hypothesis are proposed.Sirenomelia is a rare and lethal congenital anomaly. When diagnosed antenatally, termination should be offered. However, prevention is possible and should be the goal.