Stimulation of adenosine receptor enhances α1 -adrenergic receptor-mediated activation of phospholipase C and Ca2+ mobilization in a pertussis toxin-sensitive manner in FRTL-5 thyroid cells

AbstractNorepinephrine (NE) stimulated FRTL-5 thyroid cells via an α1-adrenergic receptor, resulting in cytosolic Ca2+ ([Ca2+]i) mobilization and activation of phospholipase C. Adenosine and its receptor agonist, phenylisopropyladenosine (PIA), although not exerting a direct effect, markedly enhanced the NE-induced changes. Basal NE action was not totally abolished whereas the permissive action of adenosine and PIA was completely abolished by pretreatment of the cells with islet-activating protein (IAP), pertussis toxin. The decrease in cAMP level induced by adenosine or PIA is not the cause of their permissive effect, since this effect was not reversed by the addition of cAMP-increasing agents. We conclude that an IAP substrate GTP-binding protein(s) plays a novel role in forming a stimulatory coupling between an adenosine receptor and an α1-adrenergic receptor-coupled phospholipase C system

Application of cloud particle sensor sondes for estimating the number concentration of cloud water droplets and liquid water content: case studies in the Arctic region

A cloud particle sensor (CPS) sonde is an observing system attached with a radiosonde sensor to observe the vertical structure of cloud properties. The signals obtained from CPS sondes are related to the phase, size, and number of cloud particles. The system offers economic advantages including human resource and simple operation costs compared with aircraft measurements and land-/satellite-based remote sensing. However, the observed information should be appropriately corrected because of several uncertainties. Here we made field experiments in the Arctic region by launching approximately 40 CPS sondes between 2018 and 2020. Using these data sets, a better practical correction method was proposed to exclude unreliable data, estimate the effective cloud water droplet radius, and determine a correction factor for the total cloud particle count. We apply this method to data obtained in October 2019 over the Arctic Ocean and March 2020 at Ny-Ålesund, Svalbard, Norway, to compare with a particle counter aboard a tethered balloon and liquid water content retrieved by a microwave radiometer. The estimated total particle count and liquid water content from the CPS sondes generally agree with those data. Although further development and validation of CPS sondes based on dedicated laboratory experiments would be required, the practical correction approach proposed here would offer better advantages in retrieving quantitative information on the vertical distribution of cloud microphysics under the condition of a lower number concentration

Modification with platinum of silver-deposited nickel wire electrodes for electrocatalytic oxidation of alcohols

A silver-deposited nickel (Ag/Ni) wire electrode was prepared via a galvanic replacement reaction between Ag⁺ and Ni wire in aqueous solution. It was then found that the Ag/Ni wire electrode could be modified with Pt simply by treating it in an aqueous solution of K₂PtCl₄. Although the deposition of Ag on Ni wire was limited in amount, forming Ag deposits less than 100 nm in size, a considerable increase in the electrocatalytic currents for the oxidation of alcohols could be observed after further modification of the Ag/Ni wire electrodes with Pt. This is in contrast to the fact that it was difficult to produce sufficient electrocatalytic response by modifying Ni wire with Pt directly via a simple galvanic replacement between PtCl₄²⁻ and Ni wire. Thus, the prior deposition of Ag was found to strongly promote modification with Pt via a simple stepwise treatment using AgNO₃ and K₂PtCl₄. This approach should be effective in modifying various Ni materials with Pt, including Ni microparticles

Codeposition of Platinum and Gold on Nickel Wire Electrodes via Galvanic Replacement Reactions for Electrocatalytic Oxidation of Alcohols

Codeposition of Pt and Au on Ni wire was performed using a simple treatment of immersing Ni wire in aqueous solutions containing both K₂PtCl₄ and HAuCl₄. For evaluating the electrochemical properties of the thus-prepared electrodes, cyclic voltammograms (CVs) of 1.0 M ethanol in 1.0 M NaOH aqueous solutions were recorded. Compared with Pt- or Au-deposited Ni wire electrodes prepared by treating Ni wire in aqueous solutions of a single component, e.g., 1.0 mM K₂PtCl₄ or 1.0 mM HAuCl₄, a noteworthy increase in the electrocatalytic current was observed for the oxidation of ethanol with a PtAu-codeposited Ni (PtAu/Ni) wire electrode even when it was prepared in an aqueous solution containing both 0.10 mM K₂PtCl₄ and 0.10 mM HAuCl₄. In addition, the shape and the peak potentials of CVs recorded using PtAu/Ni wire electrodes were found to be different from those recorded with the Pt- or Au-deposited Ni wire electrodes. Because the CV responses typical of the PtAu/Ni wire electrodes were observed even when a PtAu/Ni wire electrode was prepared in an aqueous solution containing both 0.010 mM K₂PtCl₄ and 1.0 mM HAuCl₄, it is considered that a small amount of Pt was effectively modified or incorporated and affected the electrochemical properties significantly. The CV results for ethanol oxidation were compared with those for the electrocatalytic oxidations of methanol, 1-propanol, and 2-propanol. Besides, the CV results recorded with the present PtAu/Ni wire electrodes are discussed in comparison with some previous results obtained using other PtAu nanoelectrocatalysts

Serum Apolipoprotein M Levels are Correlated with Biomarkers of Coagulation

Background:Apolipoprotein M (ApoM) is bound to high-density lipoprotein (HDL) in plasma, and HDL has anticoagulation effects. However, the association between ApoM and biomarkers of coagulation was unclear. Therefore, we investigated relationships between ApoM and biomarkers of coagulation. Methods: Serum samples from 233 Japanese participants including with diabetes mellitus, hypertension, dyslipidemia, or healthy controls were analyzed. Serum ApoM levels were measured using Enzyme-Linked Immuno-Sorbent Assay(ELISA). Results:Analysis of all 233 participants showed that ApoM levels were positively correlated with age (r＝0.284, p＜0.001), total cholesterol (TC;r＝0.477, p＜0.001), HDL-cholesterol (HDL-C;r＝0.234, p＜0.001) and lowdensity lipoprotein cholesterol (LDL-C;r＝0.331, p＜0.001). Higher ApoM levels were correlated with shorter activated partial thromboplastin time(APTT;r＝－0.226,p＝0.001) and prothrombin time(PT,％;r＝0.326,p＜ 0.001). Separate analysis of the 115 healthy controls showed that ApoM levels were positively correlated with age, TC, HDL-C and LDL-C, and higher ApoM levels were correlated with shorter PT. Conclusion:Serum levels of ApoM may influence biomarkers of coagulation

Mutations in the pH-Sensing G-protein-Coupled Receptor GPR68 Cause Amelogenesis Imperfecta

Amelogenesis is the process of dental enamel formation, leading to the deposition of the hardest tissue in the human body. This process requires the intricate regulation of ion transport and controlled changes to the developing enamel matrix pH. The means by which the enamel organ regulates pH during amelogenesis is largely unknown. We identified rare homozygous variants in GPR68 in three families with Amelogenesis Imperfecta, a genetically and phenotypically heterogeneous group of inherited conditions associated with abnormal enamel formation. Each of these homozygous variants (a large in-frame deletion, a frameshift deletion and a missense) were predicted to result in loss of function. GPR68 encodes a proton sensing G-protein-coupled receptor with sensitivity in the pH range that occurs in the developing enamel matrix during amelogenesis. Immunohistochemistry of rat mandibles confirmed localisation of GPR68 in the enamel organ at all stages of amelogenesis. Our data identify a role for GPR68 as a proton sensor that is required for proper enamel formation

Role of sphingosine 1-phosphate in anti-atherogenic actions of high-density lipoprotein

The reverse cholesterol transport mediated by high-density lipoprotein (HDL) is an important mechanism for maintaining body cholesterol, and hence, the crucial anti-atherogenic action of the lipoprotein. Recent studies, however, have shown that HDL exerts a variety of anti-inflammatory and anti-atherogenic actions independently of cholesterol metabolism. The present review provides an overview of the roles of sphingosine 1-phosphate (S1P)/S1P receptor and apolipoprotein A-I/scavenger receptor class B type I systems in the anti-atherogenic HDL actions. In addition, the physiological significance of the existence of S1P in the HDL particles is discussed