Low Chloride Solution Research Articles

SLC26A11 Inhibition Reduces Oncotic Neuronal Death and Attenuates Stroke Reperfusion Injury

Neuronal swelling is a pathological feature of stroke which contributes to the formation of cytotoxic edema. Under hypoxic condition, aberrant accumulation of sodium and chloride ions inside neurons increases osmotic pressure, leading to cell volume increase. Sodium entry pathway in neurons has been studied extensively. Here, we determine whether SLC26A11 is the major chloride entry pathway under hypoxia and could be the target for protection against ischemic stroke. In this study, electrophysiological properties of chloride current in primary cultured neurons were characterized using low chloride solution, 4,4′-diisothiocyano-2,2′-stilbenedisulfonic acid, and SLC26A11-specific siRNA under physiological conditions or ATP-depleted conditions. In vivo effect of SLC26A11 was evaluated on a rat stroke reperfusion model. We found that SLC26A11 mRNA in primary cultured neurons was upregulated as early as 6 h after oxygen glucose deprivation, and later, the protein level was elevated accordingly. Blockade of SLC26A11 activity could reduce chloride entry and attenuate hypoxia-induced neuronal swelling. In the animal stroke model, SLC26A11 upregulation was mainly located in surviving neurons close to the infarct core. SLC26A11 inhibition ameliorates infarct formation and improves functional recovery. These findings demonstrate that SLC26A11 is a major pathway for chloride entry in stroke, contributing to neuronal swelling. Inhibition of SLC26A11 could be a novel therapeutic strategy for stroke.

Modeling and Predicting Reduction Reaction Kinetics for a Stainless-Steel in NaCl Solutions

A method for analyzing cathodic polarization curves on stainless steels is described and a framework for predicting the cathodic polarization response for UNS S13800 is developed, including a model for the diffusivity of dissolved oxygen as a function of chloride concentration and temperature. The cathodic polarization behavior of UNS S13800 in NaCl solutions, ranging from dilute to saturated, and across a range of temperature values was studied using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and X-ray photoelectron spectroscopy (XPS). Analysis of the data indicated that the concentration of the solutions affected the ability of the oxide to catalyze reduction reactions. Dilute-to-low concentration solutions exhibited different Tafel slopes in the ORR-activation region while middle-to-high concentration solutions exhibited a single Tafel slope. The XPS and EIS results show a slightly thicker oxide formed in the low chloride concentration solutions over the course of the 18 hour open circuit duration along with a higher concentration of Fe3+ species.. The EIS data also showed the oxide formed in the low chloride solution had a higher charge-transfer resistance while the oxide formed in the high chloride solution had a higher oxide resistance.

Stress Corrosion Cracking of 13Cr-5Ni-2Mo Martensitic Stainless Steel in Methanol

We report a preliminary study of stress corrosion cracking (SCC) of a 13Cr-5Ni-2Mo martensitic stainless steel (UNS S41426), 110 ksi grade in methanol at 82°C. SCC was predominantly intergranular, although transgranular cracking also occurred at low chloride solutions. SCC was eliminated by the absence of oxygen and/or the presence of water. The presence of copper exacerbated the cracking slightly.

Normal Saline Versus Low Chloride Solutions in Treatment of Diabetic Ketoacidosis: A Systematic Review of Clinical Trials.

Traditionally, normal saline solution (NSS) has been the fluid of choice in diabetic ketoacidosis (DKA) patients, but the NSS is an acidic fluid and may lead to the delayed resolution of DKA. A systemic review search was conducted on PubMed, Embase, and Central Cochrane Registry to compare the efficacy of low chloride solutions with normal saline solution in DKA resolution. Randomized clinical trials with normal saline as a control arm and low chloride solutions as an intervention arm were included. Four studies were included in the analysis. The investigated outcomes, including time to resolution for DKA and duration of insulin infusion, varied depending on the endpoint were reported in the studies. Overall, balanced solutions were generally associated with faster correction of pH. The time to reach overall DKA endpoints was comparable in both groups. We concluded that crystalloid solutions may be used as an initial resuscitation fluid in the DKA population and may lead to earlier resolution of acidosis. More clinical trial data is required to reach statistical significance for the hypothesis.

Noble metals doped tin dioxide for sodium hypochlorite synthesis from low concentrated NaCl solutions

AbstractBACKGROUNDCreation of anode materials with high selectivity to the target process is the main problem in low concentration sodium chloride (NaCl) solutions. A specificity of such solutions is the achievement of high potentials at which the anodes traditionally used for the synthesis of chlorine [rutile oxide/titania (RuO2‐TiO2)] are destroyed. The main aim of the work concerns the eveluation of the effect of platinum (Pt) group metals in a tin oxide (SnO2) matrix on the electrocatalytic activity and selectivity in reactions of the synthesis of sodium hypochlorite and chlorate (NaClO and NaClO3) and oxygen (O2) evolution.RESULTSIt was revealed that palladium (Pd) in oxide Ti/SnO2‐Pd and Ti/SnO2‐Pt‐Pd coatings existed in the PdO form, which has a high affinity for hydroxylation. Electrocatalytic activity of coatings in anode processes in low concentrated chloride‐containing solutions would be determined by the bond strength of chemisorbed with the surface O‐containing particles. Participation in the process of Cl‐ oxidation of labile O‐containing particles increased the rate of formation of NaClO and led to inhibition of adverse reactions of O2 evolution and synthesis of chlorates and chlorites.CONCLUSIONA correlation between the selectivity of formation of NaClO and NaClO3, and the activity of the catalyst in the O2 evolution reaction is proposed. Significant formation of chlorates occurred only at the anodes, where in 1 mol L–1 HClO4 the O2 evolution potential was >1.58 V. Parameters influencing the electrocatalytic activity and selectivity of electrode materials in the target process were proposed based on this dependence. © 2021 Society of Chemical Industry (SCI).

Urine the Right Direction: The Consensus Statement From the Committee on Transplant Anesthesia of the American Society of Anesthesiologists on Fluid Management During Kidney Transplantation.

Urine the Right Direction: The Consensus Statement From the Committee on Transplant Anesthesia of the American Society of Anesthesiologists on Fluid Management During Kidney Transplantation.

Comparison of normal saline solution with low-chloride solutions in renal transplants: a meta-analysis

BackgroundNormal saline solution (NSS) has been the fluid of choice for renal transplant patients, but it can lead to hyperchloremic acidosis and hyperkalemia. This study was performed to compare the safety profile of low-chloride solutions with that of NSS in renal transplant patients.MethodsWe conducted a systemic review search on PubMed, Embase, and the Central Cochrane Registry. Randomized clinical trials (RCTs) and matched cohort studies involving NSS as the control arm and low-chloride solutions as an intervention arm were chosen. The standardized mean difference for continuous variables, the odds ratio (OR) for discrete variables, and a 95% confidence interval (CI) for effect sizes were used. A p-value of <0.05 was considered statistically significant. Analysis was performed using a random-effects model irrespective of heterogeneity, which was evaluated using I2 statistics.ResultsNine RCTs and one cohort study with a total of 726 patients were included. After transplantation, serum potassium was significantly lower in the low-chloride group (standardized mean difference compared to NSS group, –0.38 mEq/L; 95% CI, –0.66 to –0.11; p = 0.007). Similarly, postoperative chloride was lower in the low-chloride group (–2.41 mEq/L [–3.34 to –1.48], p < 0.001). No statistically significance was observed in delayed graft function (OR, 0.98 [0.56–1.69], p = 0.93), day 3 creatinine (–0.14 mg/dL [–0.46 to 0.18], p = 0.38), or day 7 urine output (–0.08 L [–0.29 to 0.12], p = 0.43).ConclusionUse of NSS during renal transplant leads to increased incidence of hyperchloremic acidosis with subsequent hyperkalemia, but clinical significance in the form of delayed graft function or postoperative creatinine remains comparable to that of low-chloride solutions.

Corrosion inhibition of AA3003 aluminum alloy by self-assembled layers of myristic acid

PurposeThis paper aims to prepare highly hydrophobic films on aluminum AA3003 using myristic acid (MA) and evaluate its corrosion protection efficiency in a low-chloride solution.Design/methodology/approachThe aluminum surface was initially treated with boiling water to develop a porous nanostructure, and then surface modification was carried out in ethanolic solutions with different concentrations of MA. The surface morphology, wetting behavior and film composition were first characterized, and then, the corrosion behavior was evaluated with electrochemical techniques.FindingsThe best hydrophobicity and corrosion resistance were obtained with 50 mM of MA. For such concentration, a water contact angle of 140° and protective efficiency of 96% were achieved. A multilayer structure was revealed by scanning electron microscope and X-ray photoelectron spectroscopy.Originality/valueThe results of this work shed light on the anticorrosion performance of fatty acid self-assembled multilayers on the surface of Al–Mn alloys.

Capacitive desalination of a low concentration aqueous sodium chloride solution based on a SnO2 and polystyrene co-functionalized graphene oxide electrodes

Capacitive desalination for low concentration saline water (NaCl concentration of <60 mg/L) is becoming ever more important and challenging due to its application in special circumstances, such as water purifiers in pacemakers and precision instruments for integrated circuit boards. Here, we develop SnO2 and aminated polystyrene co-functionalized graphene oxide nanocomposites (SnO2/PPAS-rGO) for the effective removal of low concentration NaCl in water. The excellent electrical and hydrophilic properties of SnO2 can effectively reduce the resistivity and improve the wettability of the entire material, making up for the disadvantage of the hydrophobicity of polymer. The introduction of the N atoms of amphiphilic zwitterionic SnO2/PPAS-rGO can improve the adsorption performance as a result of the interfacial interaction between lone-pair electrons and salt ions, and SnO2 can accelerate the charge transmission and furnish sites for activated adsorption. Polystyrene chains with the SnO2 nanoparticles can maintain the exposure of active sites by preventing the aggregation of GO sheets and inhibit the side reaction between the electrode and electrolyte, thereby guaranteeing structural stability with the aid of polytetrafluoroethylene as a binder. After optimizing the synthetic parameters, SnO2/PPAS-rGO-120 presents an ultrahigh electrosorption capacity of 8.07 mg/g at a cell voltage of 1.8 V with a flow rate of 20 mL/min in an aqueous 30.5 mg/L NaCl solution. Most importantly, SnO2/PPAS-rGO-120 shows an excellent adsorption rate (0.0014 s−1), reversibility and regeneration performance during multiple capacitive desalination processes.

Study Protocol for Better Evidence for Selecting Transplant Fluids (BEST-Fluids): a pragmatic, registry-based, multi-center, double-blind, randomized controlled trial evaluating the effect of intravenous fluid therapy with Plasma-Lyte 148 versus 0.9% saline on delayed graft function in deceased donor kidney transplantation

BackgroundDelayed graft function, the requirement for dialysis due to poor kidney function post-transplant, is a frequent complication of deceased donor kidney transplantation and is associated with inferior outcomes and higher costs. Intravenous fluids given during and after transplantation may affect the risk of poor kidney function after transplant. The most commonly used fluid, isotonic sodium chloride (0.9% saline), contains a high chloride concentration, which may be associated with acute kidney injury, and could increase the risk of delayed graft function. Whether using a balanced, low-chloride fluid instead of 0.9% saline is safe and improves kidney function after deceased donor kidney transplantation is unknown.MethodsBEST-Fluids is an investigator-initiated, pragmatic, registry-based, multi-center, double-blind, randomized controlled trial. The primary objective is to compare the effect of intravenous Plasma-Lyte 148 (Plasmalyte), a balanced, low-chloride solution, with the effect of 0.9% saline on the incidence of delayed graft function in deceased donor kidney transplant recipients. From January 2018 onwards, 800 participants admitted for deceased donor kidney transplantation will be recruited over 3 years in Australia and New Zealand. Participants are randomized 1:1 to either intravenous Plasmalyte or 0.9% saline peri-operatively and until 48 h post-transplant, or until fluid is no longer required; whichever comes first. Follow up is for 1 year. The primary outcome is the incidence of delayed graft function, defined as dialysis in the first 7 days post-transplant. Secondary outcomes include early kidney transplant function (composite of dialysis duration and rate of improvement in graft function when dialysis is not required), hyperkalemia, mortality, graft survival, graft function, quality of life, healthcare resource use, and cost-effectiveness. Participants are enrolled, randomized, and followed up using the Australia and New Zealand Dialysis and Transplant (ANZDATA) Registry.DiscussionIf using Plasmalyte instead of 0.9% saline is effective at reducing delayed graft function and improves other clinical outcomes in deceased donor kidney transplantation, this simple, inexpensive change to using a balanced low-chloride intravenous fluid at the time of transplantation could be easily implemented in the vast majority of transplant settings worldwide.Trial registrationAustralian New Zealand Clinical Trials Registry: ACTRN12617000358347. Registered on 8 March 2017. ClinicalTrials.gov: NCT03829488. Registered on 4 February 2019.

Investigation of the effect of low temperature aging on the mechanical properties and susceptibility to sulfide stress corrosion cracking of 22%Cr duplex stainless steel

Duplex stainless steels (DSS) are corrosion resistant alloys largely used in the oil and gas production industry. Optimum properties are usually obtained with equal fractions of ferrite (δ) and austenite (γ) in the microstructure, which can be obtained by a proper solution heat treatment. However, work hardening can be used for applications where mechanical resistance must be increased, such as in casing and tubulars for oil and gas production. These pipes operate under high pressure in a harsh environment, composed by oil and high chloride water, low pH and high H2S and CO2 partial pressures. Additional strengthening can also be provided by low temperature aging which promotes the fine precipitation of a Cr-rich α’ phase by spinodal decomposition of ferrite. In this work, a DSS with 22%Cr (UNS S31803) received with an un-balanced microstructure (64% of ferrite), was aged at 475 °C for 8 h. For comparison, the material was correctly solution treated to obtain a balanced microstructure, and aged in the same way of the as received one. The effects on tensile mechanical properties, hardness and impact toughness were determined. The sulfide stress corrosion (SSC) susceptibility was evaluated by slow strain rate tensile (SSRT) tests in low pH and high pH2S chloride solution.

Influence of chloride ion adsorption on the kinetics and mechanism of Ru(NH3)63+/2+ electrode reactions

In the experiment, we prepared metal electrodes with sub-micron to nanometer for the scanning electrochemical microscopy to study the kinetics of Ru(NH3)63+/2+ redox system. The rates of reduction of Ru(NH3)6(NO3)3 were found essentially independent of the nature of the electrode material, but mildly dependent upon chloride ion concentration. We observed that the ‘outer-sphere’ reactant of Ru(NH3)6(NO3)3 reduced at relatively slower rates in low-chloride solutions. This phenomenon appears to be compatible with the expected variations in a ligand-bridged mechanism in which the electrostatic repulsions among the specifically adsorbed chloride anions that dominate would have an adverse influence on the adsorption of inner-sphere cationic reactants and thus cause a decrease in the reaction rate. However, as 0.1 M supporting electrolyte KCl was added into the target solution, a significant increase in the reaction rate was measured as a result of the ionic double-layer effect. Cationic complexes will experience the same electrostatic attraction from adsorbed chloride anions as will outer-sphere reactants. It is suggested that the reaction pathway of Ru(NH3)63+ reduction can change from the anion-bridged inner-sphere to the outer-sphere with increasing chloride ion concentration up to 0.1 M.

Low-chloride versus high-chloride hypertonic solution for the treatment of subarachnoid hemorrhage-related complications (The ACETatE trial): study protocol for a pilot randomized controlled trial

BackgroundAneurysmal subarachnoid hemorrhage (aSAH) is a life-threatening condition that results from a ruptured cerebral vessel. Cerebral edema and vasospasm are common complications and frequently require treatment with hypertonic solutions, in particular hypertonic sodium chloride (NaCl). We have previously shown that hyperchloremia in patients with aSAH given hypertonic NaCl is associated with the development of acute kidney injury (AKI), which leads to higher morbidity and mortality. Our current trial aims to study the effect of two hypertonic solutions with different chloride content on serum chloride concentrations in patients with aSAH who are at risk for AKI.MethodsA low ChloridE hyperTonic solution for brain Edema (ACETatE) is a single center, double-blinded, double-dummy pilot trial comparing bolus doses of 23.4% NaCl and 16.4% NaCl/Na-Acetate for the treatment of cerebral edema in patients with aSAH. All patients will be enrolled within 36 h following admission. Randomization will occur once patients who receive hypertonic treatment for cerebral edema develop hyperchloremia (serum Cl− concentration ≥ 109 mmol/L). Subsequent treatment will consist of either NaCl 23.4% or NaCl/Na-Acetate 16.4%. The primary outcome of this study will be the change in serum Cl− concentrations during treatment. Secondary outcomes will include incidence of AKI, mortality, changes in intracranial pressure, and extent of hypernatremia.DiscussionIn patients with aSAH, hyperchloremia is a known risk factor for subsequent development of AKI. The primary goal of this pilot study is to determine the effect of two hypertonic solutions with different Cl− content on serum Cl− concentrations in patients with aSAH who have already developed hyperchloremia. Data will be collected prospectively to determine the extent to which the choice of hypertonic saline solution affects subsequent serum Cl− concentrations and the occurrence of AKI. This approach will allow us to obtain preliminary data to design a large randomized trial assessing the effects of chloride-sparing hypertonic solutions on development of AKI in patients with SAH. This pilot study is the first to prospectively evaluate the relationship between hypertonic solution chloride content and its effect on serum electrolytes and renal function in aSAH patients at risk of AKI due to hyperchloremia.Trial registrationClinicaltrials.gov, NCT03204955. Registered on 28 June 2017.

Rectification of oxygen transfer through the rat colonic epithelium.

AIMTo assess whether higher sensitivity of colonic epithelium to hypoxia at the serosal side is associated with oxygen transfer asymmetry.METHODSRats were fed either with normal chow or a low-sodium diet. Tissues were mounted as flat sheets in a modified, airtight Ussing chamber with oxygen meters in each hemichamber. Mucosal samples from normal diet animals were studied under control conditions, in low-chloride solution and after adding chloride secretion inhibitors and chloride secretagogues. Samples from sodium-deprived rats were studied before and after ouabain addition. In separate experiments, the correlation between short-circuit current and oxygen consumption was analyzed. Finally, hypoxia was induced in one hemichamber to assess the relationship between its oxygen content and the oxygen pressure difference between both hemichambers.RESULTSIn all studied conditions, oxygen consumption was larger in the serosal hemichamber than in the mucosal one (P = 0.0025 to P < 0.0001). Short-circuit current showed significant correlation with both total oxygen consumption (r = 0.765; P = 0.009) in normoxia and oxygen consumption in the serosal hemichamber (r = 0.754; P = 0.011) during mucosal hypoxia, but not with oxygen consumption in the mucosal hemichamber. When hypoxia was induced in the mucosal hemichamber, an oxygen pressure difference of 13 kPa with the serosal hemichamber was enough to keep its oxygen content constant. However, when hypoxia was induced in the serosal hemichamber, the oxygen pressure difference with the mucosal hemichamber necessary to keep its oxygen content constant was 40 kPa (P < 0.0001).CONCLUSIONSerosal oxygen supply is more readily available to support short-circuit current. This may be partly due to a rectifying behavior of transepithelial oxygen transfer.

Fluid composition and acute kidney injury.

To describe recent advances in the understanding of the role of fluid composition in renal outcomes in critically ill patients. The debate on fluid composition is now focused in a pragmatic discussion on fluid electrolyte composition. The resurgence of this debate was propelled by several observational studies that suggested that balanced (i.e., low chloride) solutions were associated with less acute kidney injury in critically ill patients. Nevertheless, a cluster randomized trial failed to show any benefit of balanced solutions. This trial, however, may have failed to detect an effect because of low global illness severity and little fluid infused. If balanced solutions are to be associated with less acute kidney injury, it will probably be in high risk, aggressively resuscitated patients. Additionally, the causal loop involving unbalanced solution infusion, induction of hyperchloremia and acute kidney injury is yet to be closed. Other factors, such as buffer type, speed of infusion and temperature, among others, may also be important. Recent evidence suggests that crystalloid fluid composition matters and can influence renal outcomes in critically ill patients. Further studies should assess the impact and cost-efficiency of balanced solutions in the context of high-risk scenarios.

Calcium Current Properties and Leak Conductance in Mouse Muscle Fibers Overexpressing a Type 1 Hypokalemic Periodic Paralysis Mutant L-Type Calcium Channel

Missense mutations in the gene encoding the alpha1 subunit of the L-type calcium channel CaV1.1 induce type 1 Hypokalemic Periodic Paralysis (HypoPP1). These mutations mainly occur at arginine residues in the fourth transmembrane segment of voltage-sensor domains. Very few studies have investigated the acute effects of these mutations on channel function and muscle membrane electrical properties because of the difficulty to express Cav1.1 in heterologous systems. In the present study we successfully transferred by electroporation the genes encoding the turboGFP-tagged human wildtype (WT) and R1239H HypoPP1 mutant Cav1.1 into hind limb mouse muscles. The expression profile of the two channels showed a regular striated pattern indicative of the localization of the channels in the t-tubule membrane. Measurement of the L-type current using the silicone-clamp technique showed that the maximal conductance and the voltage-dependence of the Cav1.1 channel were significantly reduced and shifted towards negative potentials respectively in fibers expressing R1239H Cav1.1 as compared to fibers expressing WT Cav1.1. Applying voltage ramps from a holding potential of 0, −20, −40 or −60 mV to −120 mV in the presence of an external low-chloride, sodium-free and potassium-free solution revealed a significant higher leak conductance measured between −80 and −120 mV in fibers expressing R1239H Cav1.1. Acidification of the external solution significantly increased the leak inward current, leak conductance and the fluorescence of an internally loaded pH indicator in fibers expressing R1239H. These data suggest that an elevated leak inward current, likely carrying protons, flows at resting membrane potentials in fibers expressing R1239H Cav1.1 and that acidification of the external medium following muscle exercise could contribute to favor the onset of muscle paralysis in HypoPP1.

Perioperative acute kidney injury

Perioperative acute kidney injury (AKI) is not uncommon and is associated with considerable morbidity and mortality. Recently, several definition systems for AKI were proposed, incorporating both small changes of serum creatinine and urinary output reduction as diagnostic criteria. Novel biomarkers are under investigation as fast and accurate predictors of AKI. Several special considerations regarding the risk of AKI are of note in the surgical patient. Co-morbidities are important risk factors for AKI. The surgery in itself, especially emergency and major surgery in the critically ill, is associated with a high incidence of AKI. Certain types of surgeries, such as cardiac and transplantation surgeries, require special attention because they carry higher risk of AKI. Nephrotoxic drugs, contrast dye, and diuretics are commonly used in the perioperative period and are responsible for a significant amount of in-hospital AKI. Before surgery, the anaesthetist is required to identify patients at risk of AKI, optimize anaemia, and treat hypovolaemia. During surgery, normovolaemia is of utmost importance. Additionally, the surgical and anaesthesia team is advised to use measures to reduce blood loss and avoid unnecessary blood transfusion. Hypotension should be avoided because even short periods of mean arterial pressure <55-60 mm Hg carry a risk of postoperative AKI. Higher blood pressures are probably required for hypertensive patients. Urine output can be reduced significantly during surgery and is unrelated to perioperative renal function. Thus, fluids should not be given in excess for the sole purpose of avoiding or treating oliguria. Use of hydroxyethyl starch needs to be reconsidered. Recent evidence indicates a beneficial effect of administering low-chloride solutions.

Mechanisms underlying spontaneous constrictions of postcapillary venules in the rat stomach.

Postcapillary venules (PCVs) play a critical role in regulating capillary hydrostatic pressure, but their contractile mechanisms are not well understood. We examined the properties of spontaneous vasomotion and corresponding Ca(2+) transients in gastric PCV. In the rat gastric submucosa, changes in PCV diameter and intracellular Ca(2+) dynamics were visualised by video tracking system and fluorescent Ca(2+) imaging, respectively, while PCV morphology was examined by immunohistochemistry. Stellate-shaped PCV mural cells expressing α-smooth muscle actin exhibited synchronised spontaneous Ca(2+) transients to develop vasomotion which was abolished by nifedipine (1 μM), cyclopiazonic acid (10 μM), or Ca(2+)-activated Cl(-) channel inhibitors (100 μM niflumic acid, 1 μM T16Ainh-A01). A gap junction blocker (3 μM carbenoxolone) disrupted the synchrony of spontaneous Ca(2+) transients amongst PCV mural cells and attenuated spontaneous vasomotion. Low chloride solution ([Cl(-)]0 = 12.4 mM) also disrupted the synchrony of spontaneous Ca(2+) transients and abolished vasomotion. Na(+)-K(+)-Cl(-) co-transporter inhibitors (10 μM bumetanide, 30 μM furosemide) suppressed spontaneous Ca(2+) transients and vasoconstrictions. A phosphodiesterase type 5 (PDE5) inhibitor (1 μM tadalafil) disrupted the spontaneous Ca(2+) transient synchrony and abolished vasomotion in a nitric oxide (NO)-dependent manner. Thus, gastric PCVs exhibit spontaneous vasomotion, resulting from synchronised spontaneous Ca(2+) transients within a network of stellate-shaped PCV mural cells. An active Cl(-) accumulation partly via Na(+)-K(+)-Cl(-) co-transport appears to be fundamental in maintaining depolarisation upon the opening of Ca(2+)-activated Cl(-) channels that triggers Ca(2+) influx via voltage-dependent L-type Ca(2+) channels. Basal PDE5 activity may continuously counteract vaso-relaxing effects of endothelial NO to maintain spontaneous vasomotion.

Electrophysiological Characteristics of Enteric Neurons Isolated from the Immortomouse

Recently, two enteric neuronal cell lines, one fetal and the other post-natal (IM-PEN), have been developed from the H-2K(b)-tsA58 transgenic mouse (immortomouse). However, their electrophysiological properties are not known. The goal of this study was to determine the electrical excitability and ionic conductance of the immortalized postnatal enteric neuronal (IM-PEN) cell line. Whole cell patch clamp studies, immunohistochemistry and RT-PCR were performed on differentiated IM-PEN cells following propagation at 33 °C and differentiation at 37 °C. Differentiated IM-PEN cells stained positively for the neuron specific markers βIII-tubulin and PGP9.5. The mRNA for several ion channels expressed in enteric neurons were detected by RT-PCR. In current clamp, the resting membrane potential was -24.6 ± 2.1 mV (n = 6) for IM-FEN and -29.8 ± 0.9 mV (n = 30) for IM-PEN. Current injections from Vh -80 mV resulted in passive responses but not action potentials. Depolarizing pulses in the whole cell voltage clamp configuration from Vh -80 mV elicited small nifedipine-sensitive inward currents. Additionally, outward currents with slow deactivating tail currents were blocked by niflumic acid and low chloride solution. A volume-regulated anion current was elicited by hypo-osmotic solution and inhibited by 10 μM DCPIB. Growth with rabbit gastrointestinal smooth muscle did not yield significant differences in the active properties of the IM-PEN cell line. Transient expression of L-type Ca(2+) channels produced large inward currents demonstrating a working mechanism for protein folding and transport. The electrophysiological characteristics of IM-PEN cells suggest that chloride channels in IM-PEN cells play an important role in their resting state, and membrane trafficking of some of the ion channels may preclude their electrical excitability.

塩化物飛来大気腐食環境における鋼の耐候性に及ぼす Cr 添加の影響

The role of chromium contents on atmospheric corrosion of steel in the environment containing chloride ion was studied by exposure test and electrochemical experiments. It was found that corrosion resistance of 1% chromium steel was lower than that of the steel without chromium in the environment whose concentration of chloride ion was very high by the exposure test. On the other hand, containing chromium increases corrosion resistance in the environment with low chloride concentration. In neutral chloride solution corrosion rate of 1% chromium steel was lower than that of the steel without chromium, but was high in low pH chloride solution. The pH dependence of corrosion resistance of 1% chromium steel corresponded with the corrosion resistance by the exposure test.