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In maximally Ca2+-activated demembranated fibres from the mammalian skeletal muscle, the depression of the force by lowering the temperature below the physiological level (~35 °C) is explained by the reduction of force in the myosin motor. Instead, cooling is reported to not affect the force per motor in Ca2+-activated cardiac trabeculae from the rat ventricle. Here, the mechanism of the cardiac performance depression by cooling is reinvestigated with fast sarcomere-level mechanics. We determine the changes in the half-sarcomere compliance of maximally Ca2+-activated demembranated rat trabeculae in the range of temperatures of 10–30 °C and analyse the data in terms of a simplified mechanical model of the half-sarcomere to extract the contribution of myofilaments and myosin motors. We find that the changes in the ensemble force are due to changes in the force per motor, while the fraction of actin-attached motors remains constant independent of temperature. The results demonstrate that in the cardiac myosin, as in the skeletal muscle myosin, the force-generating transition is endothermic. The underlying large heat absorption indicates the interaction of extended hydrophobic surfaces within the myosin motor, like those suggested by the crystallographic model of the working stroke. [ABSTRACT FROM AUTHOR]

The regulation of heart function is attributed to a dual filament mechanism: i) the Ca2+-dependent structural changes in the regulatory proteins of the thin, actin-containing filament making actin available for myosin motor attachment, and ii) the release of motors from their folded (OFF) state on the surface of the thick filament allowing them to attach and pull the actin filament. Thick filament mechanosensing is thought to control the number of motors switching ON in relation to the systolic performance, but its molecular basis is still controversial. Here, we use high spatial resolution X-ray diffraction data from electrically paced rat trabeculae and papillary muscles to provide a molecular explanation of the modulation of heart performance that calls for a revision of the mechanosensing hypothesis. We find that upon stimulation, titin-mediated structural changes in the thick filament switch motors ON throughout the filament within ~1/2 the maximum systolic force. These structural changes also drive Myosin Binding Protein-C (MyBP-C) to promote first motor attachments to actin from the central 1/3 of the half-thick filament. Progression of attachments toward the periphery of half-thick filament with increase in systolic force is carried on by near-neighbor cooperative thin filament activation by attached motors. The identification of the roles of MyBP-C, titin, thin and thick filaments in heart regulation enables their targeting for potential therapeutic interventions. [ABSTRACT FROM AUTHOR]

Chronic kidney disease–associated pruritus (CKD-aP) is a common complication in dialysis patients which is not fully addressed by pharmacological and dialytic therapy. The objective was to review the literature on the effects of extracorporeal blood purification modalities on CKD-aP. The population comprised patients aged ≥18 years on chronic dialysis. PubMed, Embase, and Medline were systematically searched until February 2024 for clinical studies comparing the effect of different dialysis modalities on pruritus intensity. Two reviewers extracted data independently. Risk of bias for randomized controlled trials (RCTs) was assessed using the Cochrane tool. Any extracorporeal blood purification therapy for the treatment of CKD-aP was included. Outcome was quantitative change in pruritus intensity on a validated itching scale. This review included eight RCTs examining five different dialysis modalities, three observational studies examining three dialysis modalities, and six prospective clinical trials assessing four dialysis modalities. These treatments included peritoneal dialysis, low-flux and high-flux dialysis, hemodiafiltration, expanded hemodialysis, hemadsorption, hemodiafiltration with endogenous reinfusion and dialysis with polymethylmethacrylate membrane. Risk of bias was high in most studies. The largest body of evidence was found for the efficacy of hemadsorption. Limitations of evidence included heterogeneity in diagnostic tools and treatment, risk of selection bias, small sample sizes and short follow-up durations that made it challenging to perform a robust systematic review and meta-analysis. Despite the high prevalence of pruritus among dialysis patients, current evidence for efficacy of standard dialytic treatment is weak. The only technique that appears to be effective is hemoadsorption alone or coupled with hemodialysis. More high-quality studies are needed to confirm the long-term benefits. [ABSTRACT FROM AUTHOR]

Introduction: Hemadsorption with new sorbent cartridges is an emerging extracorporeal blood purification technique. Flow distribution inside the sorbent is one of the main issues concerning the device's performance and optimal sorbent utilization. In this experiment, we aimed to investigate the efficacy of vibration during adsorption by measuring the removal of vancomycin. Methods: In this experimental study, 1,000 mL of saline with 10 g of vancomycin was circulated in a closed circuit (set flow of 250 mL/min) simulating a hemadsorption blood run using HA380 minimodule cartridge containing 75 g of wet resin. This vibration model was implemented with a damping head device installed in front of the adsorption cartridge during the experiment. The kinetics of the vancomycin were assessed by removal ratio over 120 min. Results: We found no difference between the two models. Adsorption with and without vibration did not differ significantly for partial reduction ratios, overall amount of adsorbed molecule, or adsorption kinetics. Conclusion: The current design and structure of the minimodule cartridge demonstrated no difference in small-middle solute removal. Further improvement with the addition of mechanical vibration to the device was not observed. [ABSTRACT FROM AUTHOR]

The medaka fish (Oryzias latipes) is a vertebrate model used in developmental biology and genetics. Here we explore its suitability as a model for investigating the molecular mechanisms of human myopathies caused by mutations in sarcomeric proteins. To this end, the relevant mechanical parameters of the intact skeletal muscle of wild-type medaka are determined using the transparent tail at larval stage 40. Tails were mounted at sarcomere length of 2.1 μm in a thermoregulated trough containing physiological solution. Tetanic contractions were elicited at physiological temperature (10C–30C) by electrical stimulation, and sarcomere length changes were recorded with nanometer-microsecond resolution during both isometric and isotonic contractions with a striation follower. The force output has been normalized for the actual fraction of the cross section of the tail occupied by the myofilament lattice, as established with transmission electron microscopy (TEM), and then for the actual density of myofilaments, as established with X-ray diffraction. Under these conditions, the mechanical performance of the contracting muscle of the wild-type larva can be defined at the level of the half-thick filament, where ~300 myosin motors work in parallel as a collective motor, allowing a detailed comparison with the established performance of the skeletal muscle of different vertebrates. The results of this study point out that the medaka fish larva is a suitable model for the investigation of the genotype/phenotype correlations and therapeutic possibilities in skeletal muscle diseases caused by mutations in sarcomeric proteins. NEW & NOTEWORTHY The suitability of the medaka fish as a model for investigating the molecular mechanisms of human myopathies caused by mutations of sarcomeric proteins is tested by combining structural analysis and sarcomere-level mechanics of the skeletal muscle of the tail of medaka larva. The mechanical performance of the medaka muscle, scaled at the level of the myosin-containing thick filament, together with its reduced genome duplication makes this model unique for investigations of the genotype/phenotype correlations in human myopathies. [ABSTRACT FROM AUTHOR]

Background: Extracorporeal removal of bilirubin in patients with severe liver dysfunction is a key blood purification strategy. We conducted an ex vivo study to assess the quantitative capacity to remove bilirubin from plasma of a novel adsorptive cartridge. Methods: We studied a downscaled module of the BS330 Plasma Bilirubin Adsorption Column Cartridge (Jafron Biomedical, Zhuhai City, China) to minimize the plasma requirement in an ex vivo circulation using a solution of hyperbilirubinemic plasma. We measured the bilirubin concentration gap (ΔC) between inlet (Cpin) and outlet (Cpout) of the unit and we calculated the removal ratio (RR) as mass adsorbed at different time points. Moreover, we compared the ex vivo model with the bilirubin adsorption kinetics in a patient with acute on chronic liver failure treated with the BS330 cartridge. Results: Bilirubin concentration change across the cartridge at 30 min was 16.5%, and cartridge saturation was reached at 750 min. We used a minimodule downscaled to 1:3 and containing approximately 131 g of BS330 sorbent beads: the device retained 759 mg of bilirubin with a RR of 78.1% and a RR of 42.6% at 120 min. Thus, the adsorption capacity was 5.76 mg of bilirubin per gram of sorbent. Bilirubin adsorption kinetics in our clinical case with a full-scale unit shows a coherent trend with a total bilirubin mass adsorbed after 180 min of 470 mg. Discussion: Our findings provide the first assessment of bilirubin adsorption in an ex vivo model of plasma perfusion and can be used to design interventional studies in humans, providing guidance for an adequate prescription of treatment frequency and duration. [ABSTRACT FROM AUTHOR]

Introduction: Sepsis is a frequent complication in critically ill patients. Patients may require control of the source of infection, removal of pathogens and damaged cells, and organ support. Often, these targets can be achieved through the utilization of extracorporeal therapies including hemoperfusion for the adsorption of cytokines and other circulating mediators. On extracorporeal organ support, patients are generally treated with antibiotic therapy, and vancomycin is one of the most commonly used antibiotics. Because of the aspecific nature of adsorption, antibiotics can be removed from the circulation, leading to altered plasma levels and requiring prescription adjustment. The aim was to define the amount of vancomycin adsorbed by a sorbent cartridge (HA380, Jafron, China) during hemoperfusion and to establish possible strategies to maintain an effective plasma level in critically ill patients undergoing extracorporeal therapies. Methods: In vitro experiments with incremental concentrations of vancomycin in the test solution (500 and 1,000 mL) were carried out in a recirculation circuit until sorbent saturation was observed. A maximum of 10 g of vancomycin were injected and mini-modules containing 25 g of dry resin were utilized. Results: In different experiments with various concentration of vancomycin, a maximum amount of 244 mg/g of sorbent was adsorbed reaching saturation between 60 and 80 min from the beginning of the experiments. The kinetics of adsorption appears to be governed by a Langmuir-like isotherm with maximal removal speed in the early minutes and a plateau after 60 min. Discussion/Conclusion: HA380 adsorbs significant amounts of vancomycin. Adjusting the achieved results with the experimental mini-module to a full-scale cartridge, a total of 25 g of antibiotic can be removed. This might have affected outcome results in clinical trials. This suggests prescribing administration to critically ill patients requiring hemoperfusion, immediately after or in the inter-session time window. In case of administration during hemoperfusion, adequate adjustment and plasma level monitoring is strongly recommended. [ABSTRACT FROM AUTHOR]

Introduction: A well-functioning peritoneal catheter is key to success of peritoneal dialysis (PD). The Vicenza "short" catheter is a modified Tenckhoff catheter with a shorter intraperitoneal segment. The aim of this study was to evaluate the incidence of catheter-related complications and catheter survival rate using the Vicenza "short" catheter, according to the goals suggested by the International Society for Peritoneal Dialysis (ISPD) guidelines. Second, we compared insertion techniques used in our center. Methods: This is a retrospective cohort, single-center study analyzing incident PD patients undergoing Vicenza "short" peritoneal catheter placement between January 1, 2015, and December 31, 2019. As clinical outcomes, we evaluated catheter patency at 12 months, exit-site/tunnel infection and peritonitis within 30 days of catheter insertion, visceral injury, or significant hemorrhage during the procedure, in accordance with ISPD guidelines. Results: The percentage of patency at 12 months for all catheter insertion methods was 88.91%, and the percentage for laparoscopic placement was 93.75%. The exit-site/tunnel infection and peritonitis occurring within 30 days of catheter insertion were, respectively, 0.75% and 2.2%; the visceral injury leading to intervention was 0.75%. We did not have any case of significant hemorrhage. All results were in line with ISPD guidelines. Conclusion: We conclude that the Vicenza "short" catheter is a suitable device for peritoneal access. The implantation procedure is safe and easy to perform, and both nephrologists and surgeons can do it. A confident use and a proper implantation of the Vicenza "short" catheter help achieve the clinical ISPD goals for the PD access procedure in terms of catheter survival and complication rates. [ABSTRACT FROM AUTHOR]

Background: Patients on maintenance hemodialysis (HD) face complications due to the accumulation of protein-bound uremic toxins, such as advanced glycation end products (AGEs), which contribute to inflammation, oxidative stress, and cardiovascular disease. Conventional HD techniques inadequately remove AGEs. This study evaluates the efficacy of the HA130 hemoadsorption cartridge combined with high-flux HD (HF-HD) in enhancing AGE removal., Methods: This prospective, single-center study included 20 maintenance HD patients randomized into two groups: HF-HD alone (n = 10) and HF-HD plus hemoadsorption (n = 10). Blood samples were collected before and after a single session to measure carboxymethyllysine (CML), soluble RAGE (sRAGE), prolactin, and parathyroid hormone (PTH) levels. Reduction ratios (RR) were calculated, including corrected for hemoconcentration (RRc), to ensure accuracy. Statistical analyses included Mann-Whitney U and Chi-square tests., Results: The HF-HD plus hemoadsorption group showed significantly enhanced removal of CML compared to HF-HD alone, with RRc of 64.7% [52.6-74.9] versus 39.3% [33.8-49.4], respectively (p = 0.045). Similarly, uncorrected reduction ratios demonstrated a trend favoring hemoadsorption, with values of 57.5% [45.1-70.7] versus 30.3% [19.1-44.5] (p = 0.053). Importantly, sRAGE levels were preserved in both groups (RRc: 23.4% (15.1-30.4) vs. 21.8% (16.6-31.7), p = 0.791), highlighting the safety of hemoadsorption. Other biochemical parameters, including prolactin, PTH, albumin, and electrolytes, showed no significant differences between groups. All sessions were completed without adverse events., Conclusion: Combining hemoadsorption with HF-HD significantly enhances CML removal, as evidenced by corrected RR, without compromising protective sRAGE levels. This innovative approach offers a promising adjunctive therapy for reducing AGEs-related complications in end-stage renal disease patients. Further longitudinal studies are needed to confirm these findings and evaluate long-term outcomes., (© 2025 International Center for Artificial Organ and Transplantation (ICAOT) and Wiley Periodicals LLC.)

Introduction. Contrast Induced Encephalopathy (CIE) belongs to Major Adverse Renal and Cardiovascular Events (MARCE) after iodinated contrast medium (IOCM), especially for high-risk patients with several comorbidities such as hypertension, diabetes, heart failure, and Chronic Kidney Disease (CKD). We report a case of CIE in a Peritoneal Dialysis (PD)-patient. Case report. A 78-year-old, affected by diabetes, hypertension, chronic heart failure, and End Stage Renal Disease (ESRD) treated with PD, underwent a carotid Percutaneous Angioplasty (PTA). Immediately after the exam, he developed mental confusion and aphasia. Encephalic CT scan and MRI excluded acute ischemia or hemorrhage but showed cerebral oedema. Mannitol and steroids were administered and additional PD exchange was performed with depurative aim. Within 2 days the patient completely recovered. Discussion. CIE mimics severe neurological diseases. It should be considered as a differential diagnosis if symptoms occur immediately after administration of IOCM, especially in high-risk patients and in case of intra-arterial injection. Clinical presentation includes transient cortical blindness, aphasia, focal neurological defects, and confusion. CIE is often a diagnosis of exclusion, and imaging plays a significant role. Symptoms generally resolve spontaneously within 24-48h, rarely in few days. Symptomatic therapy, including mannitol and steroids could be considered. In literature, CIE is reported only in a few patients affected by ESRD treated with chronic HD, and our is the first available case of a patient treated with chronic PD who developed this rare complication., (Copyright by Società Italiana di Nefrologia SIN, Rome,Italy.)

Autosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary kidney disease and accounts for∼10% of patients on renal replacement therapy. In the last decade, no specific treatment was available and only preventive measures could be put in place to delay the onset of ESRD. Following the results of the TEMPO 3:4 study, tolvaptan was approved in many countries, for the purpose of slowing the progression of renal insufficiency. In Italy tolvaptan is available since 2016 for patients with chronic kidney disease (CKD) stage 1-3, and since 2020 for patients with CKD stage 4, who fulfil the criteria of "rapid disease progression", according to the European recommendations. After this approval, Italian nephrology units have had to change their organization to be able to identify the patients eligible for the drug and to guarantee frequent patient monitoring. In this paper, we present our three-year experiences with tolvaptan, focusing on its safety profile and tolerability, but also on the high burden of care that such therapy represents not only for doctors, but also for patients. Strategies to implement remote monitoring may be useful to reduce the burden of assistance on one side, and the medicalization of ADPKD patients in the early stage of the disease, on the other., (Copyright by Società Italiana di Nefrologia SIN, Rome, Italy.)