Alternans in Genetically Modified Langendorff-Perfused Murine Hearts Modeling Catecholaminergic Polymorphic Ventricular Tachycardia

The relationship between alternans and arrhythmogenicity was studied in genetically modified murine hearts modeling catecholaminergic polymorphic ventricular tachycardia (CPVT) during Langendorff perfusion, before and after treatment with catecholamines and a β-adrenergic antagonist. Heterozygous (RyR2p/s) and homozygous (RyR2s/s) RyR2-P2328S hearts, and wild-type (WT) controls, were studied before and after treatment with epinephrine (100 nM and 1 μM) and propranolol (100 nM). Monophasic action potential recordings demonstrated significantly greater incidences of arrhythmia in RyR2p/s and RyR2s/s hearts as compared to WTs. Arrhythmogenicity in RyR2s/s hearts was associated with alternans, particularly at short baseline cycle lengths. Both phenomena were significantly accentuated by treatment with epinephrine and significantly diminished by treatment with propranolol, in full agreement with clinical expectations. These changes took place, however, despite an absence of changes in mean action potential durations, ventricular effective refractory periods or restitution curve characteristics. Furthermore pooled data from all hearts in which arrhythmia occurred demonstrated significantly greater alternans magnitudes, but similar restitution curve slopes, to hearts that did not demonstrate arrhythmia. These findings thus further validate the RyR2-P2328S murine heart as a model for human CPVT, confirming an alternans phenotype in common with murine genetic models of the Brugada syndrome and the congenital long-QT syndrome type 3. In contrast to these latter similarities, however, this report demonstrates the dissociation of alternans from changes in the properties of restitution curves for the first time in a murine model of a human arrhythmic syndrome

Salt tolerance of halophytes, research questions reviewed in the perspective of saline agriculture

Halophytes of the lower coastal salt marsh show increased salt tolerance, and under high salinity they grow faster than upper marsh species. We could not show reduced growth rate of halophytes compared with glycophytes when grown under non-saline conditions. This indicates limited energy costs associated with high-salt tolerance in plants of genera such as Salicornia, providing a good perspective of saline agriculture cultivating Salicornia as a vegetable crop.We show that halophytes do not occur on non-saline or inland sites because of a reduced growth rate at low soil salinity, but probably due to other ecological traits of glycophytic upper marsh species. These traits provide competitive advantage over lower salt marsh halophytes, such as earlier germination and increased growing season length.Some halophytic Amaranthaceae (Salicornioideae, Chenopodioideae and Suaedoideae) are not just highly salt tolerant, their growth rate is stimulated at a salinity range of 150–300 mM NaCl. Alternatively this may be described as depressed growth at low salinity.Selective pressure for such high-salt tolerance and salt stimulated growth likely occurred with prevailing arid climate and saline soil conditions. Under such conditions highly-salt tolerant succulent Salicornioideae, Chenopodioidea and Suaedoideae may have evolved about 65 Mya. In the context of evolution and diversication of land plants this origin of highly-salt tolerant succulent plants is relatively recent.Such high-salt tolerance might be characterized as constitutive in comparison with inducible (lower) salt tolerance of other dicotyledonae and monocotyledonae (Poaceae) species. Levels of salt tolerance of the latter type span a large range of low, intermediate to high-salt tolerance, but do not include salt stimulated growth. Salt tolerant traits of the latter inducible type appear to have evolved repeatedly and independently.Early highly-salt tolerant succulent Salicornioideae, Chenopodioidea and Suaedoideae were perennial and frost sensitive and occurred in warm temperate and Mediterranean regions. A shift from the perennial Sarcocornia to an annual life form has been phylogenetically dated circa 9.4–4.2 Mya and enabled evolution of annual hygrohalophytes in more northern coastal locations up to boreal and subarctic coastal sites avoiding damage of winter frost. Diversification of such hygrohalophytes was facilitated by polyploidization (e.g. occurrence of tetraploid and diploid Salicornia species), and a high degree of inbreeding allowing sympatric occurrence of Salicornia species in coastal salt marshes.High-level salt tolerance is probably a very complex polygenic trait. It is unlikely that glycophytes would accommodate the appropriate allelic variants at all the loci involved in halophyte salt tolerance. This might explain why attempts to improve crop salt tolerance through conventional breeding and selection have been unsuccessful to date.Genetic engineering provides a viable alternative, but the choice for the appropriate transgenes is hampered by a fundamental lack of knowledge of the mechanisms of salt tolerance in halophytes. The chances to identify the determinant genes through QTL analyses, or comparisons among near isogenic lines (NILS) are limited. Salt-tolerance is usually a species-wide trait in halophytes, and intra-specific divergence in salt tolerance in facultative halophytes seems to be often associated with chromosomal incompatibility.A variety of candidate salt tolerance genes been identified in Arabidopsis thaliana, among which genes encoding Na+ and K+ transporters, and genes involved in the general stress or anti-oxidant response, or in compatible solute metabolism. Many of these genes have been over-expressed in different glycophytic hosts, which usually appeared to alleviate, to some degree, the response to high salinity levels. However, with few exceptions, there are no indications that the same genes would be responsible for the superior salt tolerance in (eu)halophytes. Comparisons of gene expression and gene promoter activity patterns between halophytes and glycophytes are, with few exceptions, virtually lacking, which is a major omission in current day salt tolerance research.Full-genome transcriptomic comparisons between halophytes and related glycophytes through deep sequencing seem to be the most promising strategy to identify candidate genetic determinants of the difference in salt tolerance between halophytes and glycophytes.The most reliable validation of any candidate gene is through silencing the gene in the halophytic genetic background, preferably down to the level at which it is expressed in the glycophyte reference species. This requires genetically accessible halophyte models, which are not available to date, with the exception of Thellungiella halophila. However, more models are required, particularly because T. halophila is not a typical halophyte. Eventually, the pyramiding of validated salt tolerance genes under suitable promoters may be expected to be a viable strategy for crop salt tolerance improvement

Efficient, non‐toxic anion transport by synthetic carriers in cells and epithelia

Transmembrane anion transporters (anionophores) have potential for new modes of biological activity, including therapeutic applications. In particular they might replace the activity of defective anion channels in conditions such as cystic fibrosis. However, data on the biological effects of anionophores are scarce, and it remains uncertain whether such molecules are fundamentally toxic. Here, we report a biological study of an extensive series of powerful anion carriers. Fifteen anionophores were assayed in single cells by monitoring anion transport in real time through fluorescence emission from halide-sensitive yellow fluorescent protein. A bis-(p-nitrophenyl)ureidodecalin shows especially promising activity, including deliverability, potency and persistence. Electrophysiological tests show strong effects in epithelia, close to those of natural anion channels. Toxicity assays yield negative results in three cell lines, suggesting that promotion of anion transport may not be deleterious to cells. We therefore conclude that synthetic anion carriers are realistic candidates for further investigation as treatments for cystic fibrosis.info:eu-repo/semantics/publishe

Why Are Outcomes Different for Registry Patients Enrolled Prospectively and Retrospectively? Insights from the Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF).

Background: Retrospective and prospective observational studies are designed to reflect real-world evidence on clinical practice, but can yield conflicting results. The GARFIELD-AF Registry includes both methods of enrolment and allows analysis of differences in patient characteristics and outcomes that may result. Methods and Results: Patients with atrial fibrillation (AF) and ≥1 risk factor for stroke at diagnosis of AF were recruited either retrospectively (n = 5069) or prospectively (n = 5501) from 19 countries and then followed prospectively. The retrospectively enrolled cohort comprised patients with established AF (for a least 6, and up to 24 months before enrolment), who were identified retrospectively (and baseline and partial follow-up data were collected from the emedical records) and then followed prospectively between 0-18 months (such that the total time of follow-up was 24 months; data collection Dec-2009 and Oct-2010). In the prospectively enrolled cohort, patients with newly diagnosed AF (≤6 weeks after diagnosis) were recruited between Mar-2010 and Oct-2011 and were followed for 24 months after enrolment. Differences between the cohorts were observed in clinical characteristics, including type of AF, stroke prevention strategies, and event rates. More patients in the retrospectively identified cohort received vitamin K antagonists (62.1% vs. 53.2%) and fewer received non-vitamin K oral anticoagulants (1.8% vs . 4.2%). All-cause mortality rates per 100 person-years during the prospective follow-up (starting the first study visit up to 1 year) were significantly lower in the retrospective than prospectively identified cohort (3.04 [95% CI 2.51 to 3.67] vs . 4.05 [95% CI 3.53 to 4.63]; p = 0.016). Conclusions: Interpretations of data from registries that aim to evaluate the characteristics and outcomes of patients with AF must take account of differences in registry design and the impact of recall bias and survivorship bias that is incurred with retrospective enrolment. Clinical Trial Registration: - URL: http://www.clinicaltrials.gov . Unique identifier for GARFIELD-AF (NCT01090362)

The grapevine (Vitis vinifera) aquaporin VvNIP2;1 is a silicon channel localized at the plasma membrane highly expressed in roots

Silicon (Si) supplementation has been shown to improve plant tolerance to different stresses and its accumulation in the aerial organs is mediated by NIP2;1 aquaporins (Lsi channels) and Lsi2-type exporters in roots. In the present study, we tested the hypothesis that grapevine expresses a functional NIP2;1 that accounts for root Si uptake and, eventually, Si accumulation in leaves. Own-rooted grapevine cuttings of the cultivar Vinhão accumulated over 0.2 % Si (dw) in leaves when irrigated with 1.5 mM Si for one month, while Si was undetected in control leaves. Real-time PCR showed that VvNIP2;1 was highly expressed in roots and in green berries. The transient transformation of tobacco leaf epidermal cells mediated by Agrobacterium tumefaciens confirmed VvNIP2;1 localization at the plasma membrane. Transport experiments in oocytes showed that VvNIP2;1 mediates Si and arsenite uptake, whereas permeability studies revealed that VvNIP2;1 expressed in yeast is unable to transport water and glycerol. Si supplementation to pigmented grape cultured cells (cv. Gamay Freáux) had no impact on the total phenolic and anthocyanin content, as well as the growth rate and VvNIP2;1 expression. Long-term experiments should help determine the extent of Si uptake over time and if gapevine can benefit from Si fertilizationinfo:eu-repo/semantics/acceptedVersio

Efficacy and Safety of Prothrombin Complex Concentrate Compared to Fresh Frozen Plasma in Cardiac Surgery: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

\ua9 2025 The Author(s). Published by Wolters Kluwer Health, Inc.Coagulopathy and bleeding are common complications following cardiac surgery, often requiring the use of hemostatic agents such as prothrombin complex concentrate (PCC) or fresh frozen plasma (FFP). This systematic review and meta-analysis compared the efficacy and safety of PCC versus FFP in adult patients undergoing cardiac surgery complicated by bleeding or coagulopathy. A comprehensive search of PubMed, Embase, and Web of Science was conducted from inception to March 30, 2025, identifying randomized controlled trials comparing these interventions. Primary outcomes included chest tube drainage within 24 hours, the number of red blood cell (RBC) units transfused, and the proportion of patients requiring RBC transfusion. Secondary outcomes were hospital and intensive care unit length of stay, the incidence of stroke or transient ischemic attack, thromboembolic events, acute kidney injury, and all-cause mortality within 30 days. Four randomized controlled trials, including 671 patients (PCC: 343; FFP: 328), were analyzed. PCC significantly reduced chest tube output [mean difference = -162.12 mL, 95% confidence interval (CI): -264.46 to -59.78, P = 0.002], number of RBC units transfused (mean difference = -0.93, 95% CI: -1.34 to -0.51, P < 0.0001), and proportion of patients requiring RBC transfusion (risk ratio = 0.81, 95% CI: 0.71-0.91, P = 0.0007). No significant differences were found in intensive care unit/hospital stay, thromboembolic events, stroke/transient ischemic attack, or mortality. Sensitivity analysis suggested a potential reduction in acute kidney injury with PCC. These findings support the selective use of PCC for bleeding management in cardiac surgery

New insights into Plagiogrammaceae (Bacillariophyta) based on multigene phylogenies and morphological characteristics with the description of a new genus and three new species.

Plagiogrammaceae, a poorly described family of diatoms, are common inhabitants of the shallow marine littoral zone, occurring either in the sediments or as epiphytes. Previous molecular phylogenies of the Plagiogrammaceae were inferred but included only up to six genera: Plagiogramma, Dimeregramma, Neofragilaria, Talaroneis, Psammogramma and Psammoneis. In this paper, we describe a new plagiogrammoid genus, Orizaformis, obtained from Bohai Sea (China) and present molecular phylogenies of the family based on three and four genes (nuclear-encoded large and small subunit ribosomal RNAs and chloroplast-encoded rbcL and psbC). Also included in the new phylogenies is Glyphodesmis. The phylogenies suggest that the Plagiogrammaceae is composed of two major clades: one consisting of Talaroneis, Orizaformis and Psammoneis, and the second of Glyphodesmis, Psammogramma, Neofragilaria, Dimeregramma and Plagiogramma. In addition, we describe three new species within established genera: Psammoneis obaidii, which was collected from the Red Sea, Saudi Arabia; and Neofragilaria stilus and Talaroneis biacutifrons from the Mozambique Channel, Indian Ocean, and illustrate two new combination taxa: Neofragilaria anomala and Neofragilaria lineata. Our observations suggest that the biodiversity of the family is strongly needed to be researched, and the phylogenetic analyses provide a useful framework for future studies of Plagiogrammaceae

Influence of oxygen levels on chondrogenesis of porcine mesenchymal stem cells cultured in polycaprolactone scaffolds

[EN] Chondrogenesis of mesenchymal stem cells (MSCs) is known to be regulated by a number of environmental factors, including local oxygen levels. The hypothesis of this study is that the response of MSCs to hypoxia is dependent on the physical and chemical characteristics of the substrate used. The objective of this study was to explore how different modifications to polycaprolactone (PCL) scaffolds influenced the response of MSCs to hypoxia. PCL, PCL-hyaluronic acid (HA), and PCL-Bioglass (R) (BG) scaffolds were seeded with MSCs derived from bone marrow and cultured for 35 days under normoxic or low oxygen conditions, and the resulting biochemical properties of the MSC laden construct were assessed. Low oxygen tension has a positive effect over cell proliferation and macromolecules biosynthesis. Furthermore, hypoxia enhanced the distribution of collagen and glycosaminoglycans (GAGs) deposition through the scaffold. On the other hand, MSCs displayed certain material dependent responses to hypoxia. Low oxygen tension had a positive effect on cell proliferation in BG and HA scaffolds, but only a positive effect on GAGs synthesis in PCL and HA scaffolds. In conclusion, hypoxia increased cell viability and expression of chondrogenic markers but the cell response was modulated by the type of scaffold used.Contract grant sponsors: VI National R&D&i Plan 2008-2011, Iniciativa Ingenio 2010, Consolider Program, CIBER Actions, Instituto de Salud Carlos III, and European Regional Development FundRódenas Rochina, J.; Kelly, DJ.; Gómez Ribelles, JL.; Lebourg, MM. (2017). Influence of oxygen levels on chondrogenesis of porcine mesenchymal stem cells cultured in polycaprolactone scaffolds. Journal of Biomedical Materials Research Part A. 105(6):1684-1691. https://doi.org/10.1002/jbm.a.36043S16841691105

Restitution analysis of alternans and its relationship to arrhythmogenicity in hypokalaemic Langendorff-perfused murine hearts

Alternans and arrhythmogenicity were studied in hypokalaemic (3.0 mM K+) Langendorff-perfused murine hearts paced at high rates. Epicardial and endocardial monophasic action potentials were recorded and durations quantified at 90% repolarization. Alternans and arrhythmia occurred in hypokalaemic, but not normokalaemic (5.2 mM K+) hearts (P < 0.01): this was prevented by treatment with lidocaine (10 μM, P < 0.01). Fourier analysis then confirmed transition from monomorphic to polymorphic waveforms for the first time in the murine heart. Alternans and arrhythmia were associated with increases in the slopes of restitution curves, obtained for the first time in the murine heart, while the anti-arrhythmic effect of lidocaine was associated with decreased slopes. Thus, hypokalaemia significantly increased (P < 0.05) maximal gradients (from 0.55 ± 0.14 to 2.35 ± 0.67 in the epicardium and from 0.67 ± 0.13 to 1.87 ± 0.28 in the endocardium) and critical diastolic intervals (DIs) at which gradients equalled unity (from −2.14 ± 0.52 ms to 50.93 ± 14.45 ms in the epicardium and from 8.14 ± 1.49 ms to 44.64 ± 5 ms in the endocardium). While treatment of normokalaemic hearts with lidocaine had no significant effect (P > 0.05) on either maximal gradients (0.78 ± 0.27 in the epicardium and 0.83 ± 0.45 in the endocardium) or critical DIs (6.06 ± 2.10 ms and 7.04 ± 3.82 ms in the endocardium), treatment of hypokalaemic hearts with lidocaine reduced (P < 0.05) both these parameters (1.05 ± 0.30 in the epicardium and 0.89 ± 0.36 in the endocardium and 30.38 ± 8.88 ms in the epicardium and 31.65 ± 4.78 ms in the endocardium, respectively). We thus demonstrate that alternans contributes a dynamic component to arrhythmic substrate during hypokalaemia, that restitution may furnish an underlying mechanism and that these phenomena are abolished by lidocaine, both recapitulating and clarifying clinical findings

Atrial arrhythmogenesis in wild-type and Scn5a+/Δ murine hearts modelling LQT3 syndrome

Long QT(3) (LQT3) syndrome is associated with abnormal repolarisation kinetics, prolonged action potential durations (APD) and QT intervals and may lead to life-threatening ventricular arrhythmias. However, there have been few physiological studies of its effects on atrial electrophysiology. Programmed electrical stimulation and burst pacing induced atrial arrhythmic episodes in 16 out of 16 (16/16) wild-type (WT) and 7/16 genetically modified Scn5a+/Δ (KPQ) Langendorff-perfused murine hearts modelling LQT3 (P < 0.001 for both), and in 14/16 WT and 1/16 KPQ hearts (P < 0.001 for both; Fisher’s exact test), respectively. The arrhythmogenic WT hearts had significantly larger positive critical intervals (CI), given by the difference between atrial effective refractory periods (AERPs) and action potential durations at 90% recovery (APD90), compared to KPQ hearts (8.1 and 3.2 ms, respectively, P < 0.001). Flecainide prevented atrial arrhythmias in all arrhythmogenic WT (P < 0.001) and KPQ hearts (P < 0.05). It prolonged the AERP to a larger extent than it did the APD90 in both WT and KPQ groups, giving negative CIs. Quinidine similarly exerted anti-arrhythmic effects, prolonged AERP over corresponding APD90 in both WT and KPQ groups. These findings, thus, demonstrate, for the first time, inhibitory effects of the KPQ mutation on atrial arrhythmogenesis and its modification by flecainide and quinidine. They attribute these findings to differences in the CI between WT and mutant hearts, in the presence or absence of these drugs. Thus, prolongation of APD90 over AERP gave positive CI values and increased atrial arrhythmogenicity whereas lengthening of AERP over APD90 reduced such CI values and produced the opposite effect