Plasma potassium rapid change

Although plasma electrolyte levels are quickly and precisely regulated in the mammalian cardiovascular system, even small transient changes in K+ , Na+ , Ca2+ , and/or Mg2+ can significantly alter physiological responses in the heart, blood vessels, and intrinsic (intracardiac) autonomic nervous system. We have used mathematical models of the human atrial action potential (AP) to explore the electrophysiological mechanisms that underlie changes in resting potential (Vr ) and the AP following decreases in plasma K+ , [K+ ]o , that were selected to mimic clinical hypokalemia...

The fungal toxin fusicoccin (FC) induces rapid cell elongation, proton extrusion and plasma membrane hyperpolarization in maize coleoptile cells. Here, these three parameters were simultaneously measured using non-abraded and non-peeled segments with the incubation medium having access to their lumen. The dose-response curve for the FC-induced growth was sigmoidal shaped with the maximum at 10-6 M over 10 h. The amplitudes of the rapid growth and proton extrusion were significantly higher for FC than those for indole-3-acetic acid (IAA)...

BACKGROUND: Routine chemistry testing is typically performed using serum or plasma to assess a patient's clinical status. At our institution, serum is the specimen type used. To reduce processing times, evaluation of plasma-based and rapid serum gel separator tubes was performed. METHODS: We compared the results of routine chemistry analytes collected in serum gel separator tubes (SST), plasma gel separator tubes (PST), rapid serum gel separator tubes (RST), and plasma tubes without gel separators (DGT)...

The association between diabetes insipidus (DI) and chronic dietary K+ deprivation is well known, but it remains uncertain how the disorder develops and whether it is influenced by the sexual dimorphism in K+ handling. Here, we determined the plasma K+ (PK ) threshold for DI in male and female mice and ascertained if DI is initiated by polydipsia or by a central or nephrogenic defect. C57BL6J mice were randomized to a control diet or to graded reductions in dietary K+ for 8 days, and kidney function and transporters involved in water balance were characterized...

OBJECTIVE: To study the biological effects of resveratrol on the growth, electrophysiology, and mitochondrial function of human granulosa cells (h-GCs). DESIGN: Preclinical study. SETTING: Electrophysiology laboratory and in vitro fertilization unit. PATIENT(S): This study included h-GCs from seven infertile women undergoing assisted reproductive techniques. INTERVENTION(S): Human ovarian Granulosa Cell Tumor (GCT) cell line COV434 and h-GCs obtained after oocyte retrieval were cultured in the absence or presence of resveratrol...

Background: Coronavirus disease 2019 (COVID-19) has resulted in more than 610,000 deaths worldwide since December 2019. Given the rapid deterioration of patients' condition before death, markers with efficient prognostic values are urgently required. During the treatment process, notable changes in plasma potassium levels have been observed among severely ill patients. We aimed to evaluate the association between average plasma potassium (Ka + ) levels during hospitalization and 30-day mortality in patients with COVID-19...

OBJECTIVE: To establish a specific and rapid ultra-high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS/MS) method for measuring ticarcillin and clavulanate levels in rat plasma. METHODS: A Waters ACQUITY BEH C18 column (50 mm × 2.1 mm, 1.7 μm) and SCIEX QTRAP® LC-MS/MS System were used. Analyses were conducted to optimize the chromatographic and MS conditions, and the pharmacokinetic parameters of ticarcillin and clavulanate were assessed...

Both ion fluxes and changes of cytosolic pH take an active part in the signal transduction of different environmental stimuli. Here we studied the anoxia-induced alteration of cytosolic K+ concentration, [K+ ]cyt , and cytosolic pH, pHcyt , in rice and wheat, plants with different tolerances to hypoxia. The [K+ ]cyt and pHcyt were measured by fluorescence microscopy in single leaf mesophyll protoplasts loaded with the fluorescent potassium-binding dye PBFI-AM and the pH-sensitive probe BCECF-AM, respectively...

BACKGROUND: Acutely, testosterone (TES) and other androgens are efficacious vasodilators, both in vitro and in vivo; however, their long-term effects on arterial blood pressure (BP) remain unclear. It was hypothesized that endogenous androgens exert long-term anti-hypertensive effects on systemic BP through a combination of genomic and nongenomic effects to enhance vasodilation of the systemic vasculature. METHODS: The long-term effects of endogenous TES and exogenous TES replacement therapy (TRT) on BP were studied in intact (InT) and castrated (CsX) male Sprague-Dawley (SD) and testicular-feminized male (Tfm, androgen receptor defective) rats (12 weeks old)...

Ion channel trafficking powerfully influences cardiac electrical activity as it regulates the number of available channels at the plasma membrane. Studies have largely focused on identifying the molecular determinants of the trafficking of the atria-specific KV 1.5 channel, the molecular basis of the ultra-rapid delayed rectifier current IKur . Besides, regulated KV 1.5 channel recycling upon changes in homeostatic state and mechanical constraints in native cardiomyocytes has been well documented. Here, using cutting-edge imaging in live myocytes, we investigated the dynamics of this channel in the plasma membrane...

BACKGROUND: Sodium-glucose cotransporter-2 inhibitors improve heart failure-related outcomes. The mechanisms underlying these benefits are not well understood, but diuretic properties may contribute. Traditional diuretics such as furosemide induce substantial neurohormonal activation, contributing to the limited improvement in intravascular volume often seen with these agents. However, the proximal tubular site of action of the sodium-glucose cotransporter-2 inhibitors may help circumvent these limitations...

INTRODUCTION: Adrenal venous sampling is useful for discriminating unilateral and bilateral hypersecretion in patients with primary aldosteronism, but it is relatively invasive. To determine the site of hypersecretion more non-invasively, we evaluated predictors of unilateral hypersecretion. MATERIALS AND METHODS: We evaluated the baseline characteristics and the results of confirmatory tests of 123 patients with primary aldosteronism who underwent adrenal venous sampling...

Summary: Ectopic adrenocorticotropic hormone (ACTH) production is an uncommon cause of Cushing's syndrome and, rarely, the source can be a phaeochromocytoma. A 55-year-old man presented following an episode of presumed gastroenteritis with vomiting and general malaise. Further episodes of diarrhoea, joint pains and palpitations followed. On examination, he was hypertensive with no clinical features to suggest hypercortisolaemia. He was subsequently found to have raised plasma normetanephrines of 3...

BACKGROUND: The optimal antiarrhythmic management of recent-onset atrial fibrillation (ROAF) or atrial flutter is controversial and there is a considerable variability in clinical treatment strategies. It is not known if potassium infusion has the potential to convert ROAF or atrial flutter to sinus rhythm (SR). Therefore, we aimed to investigate if patients with ROAF or atrial flutter and plasma-potassium levels ≤4.0 mmol/L have increased probability to convert to SR if the plasma-potassium level is increased towards the upper reference range (4...

OBJECTIVE: To evaluate the impact of the infusion of sodium lactate 500ml upon different biochemical variables and intracranial pressure in patients admitted to the intensive care unit. DESIGN: A prospective experimental single cohort study was carried out. SCOPE: Polyvalent intensive care unit of a university hospital. PATIENTS: Critical patients with shock and intracranial hypertension. PROCEDURE: A 500ml sodium lactate bolus was infused in 15min...

Kir5.1 (encoded by the Kcnj16 gene) is an inwardly rectifying K+ (Kir) channel highly expressed in the aldosterone-sensitive distal nephron of the kidney, where it forms a functional channel with Kir4.1. Kir4.1/Kir5.1 channels are responsible for setting the transepithelial voltage in the distal nephron and collecting ducts and are thereby major determinants of fluid and electrolyte distribution. These channels contribute to renal blood pressure control and have been implicated in salt-sensitive hypertension...

Anthropogenic use of water systems may cause temperature fluctuations between tributaries and large rivers for which physiological population related-effects on osmoregulatory capacity of Atlantic salmon are not well described. We simulated the downstream route in the case of the River Meuse basin to investigate the impact of a 5 °C temperature shift during smoltification on hypo-osmoregulatory capacities of smolts. Three temperature regimes were tested: control temperature-treatment (T1) without temperature shift, early (T2) or late (T3) temperature shift-treatment...

BACKGROUND: Biochemical and metabolic changes in stored RBC may influence the clinical outcome. We aimed to study the temporal changes in the biochemical parameters and the effect of buffy-coat reduction on RBC storage lesions. MATERIALS AND METHODS: A prospective observational study was conducted on fifteen RBC units five each of buffy coat reduced CPD/SAGM (quadruple bags), non-buffycoat reduced CPD/SAGM (triple bags) and non-buffycoat reduced CPDA (double bags)...

Active neurons require a substantial amount of adenosine triphosphate (ATP) to re-establish ion gradients degraded by ion flux across their plasma membranes. Despite this fact, neurons, in contrast to astrocytes, do not contain any significant stores of energy substrates. Recent work has provided evidence for a neuro-metabolic coupling between both cell types, in which increased glycolysis and lactate production in astrocytes support neuronal metabolism. Here, we established the cell type-specific expression of the Förster resonance energy transfer (FRET) based nanosensor ATeam1...

Torsades de pointes is a serious side effect of many drugs that can trigger sudden cardiac death, even in patients with structurally normal hearts. Torsadogenic risk has traditionally been correlated with the blockage of a specific potassium channel and a prolonged recovery period in the electrocardiogram. However, the precise mechanisms by which single channel block translates into heart rhythm disorders remain incompletely understood. Here we establish a multiscale exposure-response simulator that converts block-concentration characteristics from single cell recordings into three-dimensional excitation profiles and electrocardiograms to rapidly assess torsadogenic risk...