scholarly journals A highly-selective chloride microelectrode based on a mercuracarborand anion carrier

2019 ◽  
Author(s):  
Marino DiFranco ◽  
Marbella Quinonez ◽  
Rafal M. Dziedzic ◽  
Alexander M. Spokoyny ◽  
Stephen C. Cannon
Keyword(s):  
Skeletal Muscle ◽  
Liquid Membrane ◽  
Response Times ◽  
Reversal Potential ◽  
Polymeric Membrane ◽  
Membrane Electrode ◽  
Biologically Relevant ◽  
Potentiometric Response ◽  
Wide Range ◽  
Anion Carrier

ABSTRACTThe chloride gradient plays an important role in regulating cell volume, membrane potential, pH, secretion, and the reversal potential of inhibitory GABAA receptors. Measurement of intracellular chloride activity, , using liquid membrane ion-selective microelectrodes (ISM), however, has been limited by the physiochemical properties of Cl ionophores which have caused poor stability, drift, sluggish response times, and interference from other biologically relevant anions. Most importantly, intracellular HCO3− may be up to 4 times more abundant than Cl− (e.g. skeletal muscle) which places severe constraints on the required selectivity of a Cl – sensing ISM.Previously, a sensitive and highly-selective Cl sensor was developed in a polymeric membrane electrode (Badr et al. 1999) using a trinuclear Hg(II) complex containing carborane-based ligands, [9]-mercuracarborand-3, or MC3 for short. Here, we have adapted the use of the MC3 anion carrier in a liquid membrane ion-selective microelectrode and show the MC3-ISM has a linear Nernstian response over a wide range of aCl (0.1 mM to 100 mM), is highly selective for Cl over other biological anions or inhibitors of Cl transport, and has a response time of less than 5 sec. Importantly, over the physiological range of aCl (1 mM to 100 mM) the potentiometric response of the MC3-ISM is insensitive to HCO3− or changes in pH. Finally, we demonstrate the biological application of an MC3-ISM by measuring intracellular aCl, and the response to an external Cl-free challenge, for an isolated skeletal muscle fiber.

scholarly journals A highly-selective chloride microelectrode based on a mercuracarborand anion carrier

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Marino DiFranco ◽  
Marbella Quinonez ◽  
Rafal M. Dziedzic ◽  
Alexander M. Spokoyny ◽  
Stephen C. Cannon
Keyword(s):  
Skeletal Muscle ◽  
Liquid Membrane ◽  
Response Times ◽  
Reversal Potential ◽  
Polymeric Membrane ◽  
Membrane Electrode ◽  
Biologically Relevant ◽  
Potentiometric Response ◽  
Wide Range ◽  
Anion Carrier

AbstractThe chloride gradient plays an important role in regulating cell volume, membrane potential, pH, secretion, and the reversal potential of inhibitory glycine and GABAA receptors. Measurement of intracellular chloride activity, $${{\boldsymbol{a}}}_{{\boldsymbol{Cl}}}^{{\boldsymbol{i}}}$$aCli, using liquid membrane ion-selective microelectrodes (ISM), however, has been limited by the physiochemical properties of Cl− ionophores which have caused poor stability, drift, sluggish response times, and interference from other biologically relevant anions. Most importantly, intracellular $${\bf{HC}}{{\bf{O}}}_{{\bf{3}}}^{-}$$HCO3− may be up to 4 times more abundant than Cl− (e.g. skeletal muscle) which places severe constraints on the required selectivity of a Cl− – sensing ISM. Previously, a sensitive and highly-selective Cl− sensor was developed in a polymeric membrane electrode using a trinuclear Hg(II) complex containing carborane-based ligands, [9]-mercuracarborand-3, or MC3 for short. Here, we have adapted the use of the MC3 anion carrier in a liquid membrane ion-selective microelectrode and show the MC3-ISM has a linear Nernstian response over a wide range of aCl (0.1 mM to 100 mM), is highly selective for Cl− over other biological anions or inhibitors of Cl− transport, and has a 10% to 90% settling  time of 3  sec. Importantly, over the physiological range of aCl (1 mM to 100 mM) the potentiometric response of the MC3-ISM is insensitive to $${\bf{HC}}{{\bf{O}}}_{{\bf{3}}}^{-}$$HCO3− or changes in pH. Finally, we demonstrate the biological application of an MC3-ISM by measuring intracellular aCl, and the response to an external Cl-free challenge, for an isolated skeletal muscle fiber.

Potentiometric Response of Calix[4]pyrrole Liquid Membrane Electrode Towards Neutral Nitrophenols

2001 ◽  
Vol 13 (4) ◽  
pp. 342-346 ◽  
Author(s):  
Tomasz Piotrowski ◽  
Hanna Radecka ◽  
Jerzy Radecki ◽  
Stefaan Depraetere ◽  
Wim Dehaen
Keyword(s):  
Liquid Membrane ◽  
Membrane Electrode ◽  
Potentiometric Response ◽  
Liquid Membrane Electrode

scholarly journals Improved protamine-sensitive membrane electrode for monitoring heparin concentrations in whole blood via protamine titration§

1998 ◽  
Vol 44 (3) ◽  
pp. 606-613 ◽  
Author(s):  
Narayanan Ramamurthy ◽  
Narayan Baliga ◽  
Joyce A Wahr ◽  
Ulrich Schaller ◽  
Victor C Yang ◽  
...  
Keyword(s):  
Whole Blood ◽  
Accurate Method ◽  
Polymeric Membrane ◽  
Membrane Electrode ◽  
Potentiometric Response ◽  
Electrode Method ◽  
Method R ◽  
Sensitive Electrode ◽  
Point Detector

Abstract An improved protamine-sensitive electrode based on a polymeric membrane doped with the charged ion exchanger dinonylnaphthalenesulfonate (DNNS) is used for monitoring heparin concentrations in whole blood. The electrode exhibits significant nonequilibrium potentiometric response to polycationic protamine over the concentration range of 0.5–20 mg/L in undiluted whole-blood samples. The sensor can serve as a simple end point detector for the determination of heparin via potentiometric titrations with protamine. Whole-blood heparin concentrations determined by the electrode method (n ≥157) correlate well with other protamine titration-based methods, including the commercial Hepcon HMS assay (r = 0.934) and a previously reported potentiometric heparin sensor-based method (r = 0.973). Reasonable correlation was also found with a commercial chromogenic anti-Xa heparin assay (r = 0.891) with corresponding plasma samples and appropriate correction for whole-blood hematocrit levels. Whereas a significant positive bias (0.62 kU/L; P <0.001) is observed between the anti-Xa assay and the protamine sensor methods, insignificant bias is observed between the protamine sensor and the Hepcon HMS tests (0.08 kU/L; P = 0.02). The possibility of fully automating these titrations offers a potentially simple, inexpensive, and accurate method for monitoring heparin concentrations in whole blood.

Potentiometry of Na+ in undiluted serum and urine with use of an improved neutral carrier-based solvent polymeric membrane electrode.

1983 ◽  
Vol 29 (8) ◽  
pp. 1508-1512 ◽  
Author(s):  
P Anker ◽  
H B Jenny ◽  
U Wuthier ◽  
R Asper ◽  
D Ammann ◽  
...  
Keyword(s):  
Liquid Membrane ◽  
Atomic Spectrometry ◽  
Polymeric Membrane ◽  
Membrane Electrode ◽  
Selective Electrode ◽  
Direct Potentiometry ◽  
Undiluted Serum ◽  
Polymeric Membrane Electrode ◽  
Liquid Membrane Electrode ◽  
Serum And Urine

Abstract We present an improved Na+-selective liquid membrane electrode for measurement of Na+ concentrations in both undiluted serum and urine. The values for urinary Na+ obtained with the ion-selective electrode agree well with those obtained with the flame photometer. The correlation gives a standard residual deviation of +/- 2.7 mmol/L over the Na+ range of 25-280 mmol/L. In serum, this direct potentiometry yields Na+ concentrations 5.4% (SD 1.1%) higher than those obtained by atomic spectrometry and a standard residual deviation of +/- 1.1 mmol/L. Correction of these values for the volumes of protein and lipid leads to potentiometric values 1.2% (SD 0.7%) lower than those by flame photometry (residual standard deviation: +/- 1.0 mmol/L). Other factors that possibly contribute to this discrepancy are discussed.

Potentiometric Response of Liquid Membrane Electrode Incorporated with Macrocyclic Polyamine Towards Benzoate

2003 ◽  
Vol 36 (7) ◽  
pp. 1325-1334 ◽  
Author(s):  
Laura Bulgariu ◽  
Hanna Radecka ◽  
Marek Pietraszkiewicz ◽  
Oksana Pietraszkiewicz
Keyword(s):  
Liquid Membrane ◽  
Membrane Electrode ◽  
Macrocyclic Polyamine ◽  
Potentiometric Response ◽  
Liquid Membrane Electrode

scholarly journals Autophagy Deficiency by Atg4B Loss Leads to Metabolomic Alterations in Mice

Metabolites ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 481
Author(s):  
Gemma G. Martínez-García ◽  
Raúl F. Pérez ◽  
Álvaro F. Fernández ◽  
Sylvere Durand ◽  
Guido Kroemer ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Amino Acids ◽  
Mammalian Cells ◽  
Tissue Homeostasis ◽  
In Vivo Studies ◽  
Protective Mechanism ◽  
Cardiac Damage ◽  
Wide Range ◽  
First Time

Autophagy is an essential protective mechanism that allows mammalian cells to cope with a variety of stressors and contributes to maintaining cellular and tissue homeostasis. Due to these crucial roles and also to the fact that autophagy malfunction has been described in a wide range of pathologies, an increasing number of in vivo studies involving animal models targeting autophagy genes have been developed. In mammals, total autophagy inactivation is lethal, and constitutive knockout models lacking effectors of this route are not viable, which has hindered so far the analysis of the consequences of a systemic autophagy decline. Here, we take advantage of atg4b−/− mice, an autophagy-deficient model with only partial disruption of the process, to assess the effects of systemic reduction of autophagy on the metabolome. We describe for the first time the metabolic footprint of systemic autophagy decline, showing that impaired autophagy results in highly tissue-dependent alterations that are more accentuated in the skeletal muscle and plasma. These changes, which include changes in the levels of amino-acids, lipids, or nucleosides, sometimes resemble those that are frequently described in conditions like aging, obesity, or cardiac damage. We also discuss different hypotheses on how impaired autophagy may affect the metabolism of several tissues in mammals.

The Impact of Mental States on Semi-autonomous Driving Takeover Performance: A Systematic Review

2020 ◽  
Vol 64 (1) ◽  
pp. 1372-1376
Author(s):  
Gaojian Huang ◽  
Christine Petersen ◽  
Brandon J. Pitts
Keyword(s):  
Systematic Review ◽  
Autonomous Vehicles ◽  
Response Times ◽  
Autonomous Driving ◽  
Mental States ◽  
Manual Control ◽  
Monitoring Systems ◽  
Wide Range ◽  
Different Types ◽  
The Impact

Semi-autonomous vehicles still require drivers to occasionally resume manual control. However, drivers of these vehicles may have different mental states. For example, drivers may be engaged in non-driving related tasks or may exhibit mind wandering behavior. Also, monitoring monotonous driving environments can result in passive fatigue. Given the potential for different types of mental states to negatively affect takeover performance, it will be critical to highlight how mental states affect semi-autonomous takeover. A systematic review was conducted to synthesize the literature on mental states (such as distraction, fatigue, emotion) and takeover performance. This review focuses specifically on five fatigue studies. Overall, studies were too few to observe consistent findings, but some suggest that response times to takeover alerts and post-takeover performance may be affected by fatigue. Ultimately, this review may help researchers improve and develop real-time mental states monitoring systems for a wide range of application domains.

Partial blocking of ion transport at the interface of an ion-selective liquid membrane electrode by neutral surfactants

1998 ◽  
Vol 44 (1) ◽  
pp. 125-132 ◽  
Author(s):  
Qingshan Ye ◽  
A Vincze ◽  
G Horvai ◽  
F.A.M Leermakers
Keyword(s):  
Ion Transport ◽  
Liquid Membrane ◽  
Membrane Electrode ◽  
Partial Blocking ◽  
Liquid Membrane Electrode

Regulation of type II adenylyl cyclase mRNA in rabbit skeletal muscle by chronic motor nerve pacing

1996 ◽  
Vol 271 (2) ◽  
pp. E253-E260 ◽  
Author(s):  
C. E. Torgan ◽  
W. E. Kraus
Keyword(s):  
Gene Expression ◽  
Skeletal Muscle ◽  
Protein Kinase ◽  
Adenylyl Cyclase ◽  
Regulation Of Gene Expression ◽  
Rabbit Skeletal Muscle ◽  
Type Ii ◽  
Wide Range ◽  
Electrical Pacing ◽  
Fast Twitch

Skeletal muscle exhibits a wide range in functional phenotype in response to changes in physiological demands. We have observed that, in response to changes in work patterns, alterations in gene expression of some proteins coincide with changes in adenylyl cyclase (AC) activity [Kraus, W.E., J.P. Longabaugh, and S. B. Liggett. Am. J. Physiol 263 (Endocrinol. Metab. 26): E266-E230, 1992]. We now examine AC isoform transcript prevalence in various rabbit skeletal muscles and in response to changing work demands. Using reverse transcriptase-polymerase chain reaction, we detected type II AC isoform transcripts in rabbit skeletal muscle. Ribonuclease protection analyses revealed that expression of the type II isoform significantly correlated with the percentage of fast-twitch type IIb/IId fibers (r2 = 0.765, P < 0.01). When a fast-twitch muscle was converted to a slow-twitch muscle via chronic electrical pacing, expression of type II AC mRNA significantly decreased. This response occurred 3 days after the onset of stimulation (78% decrease) and was still present after 21 days of stimulation (76% decrease). As type II AC is relatively insensitive to calcium regulation while sensitive to protein kinase C (PKC) signaling, these data provide further impetus for investigations of protein kinase A and PKC cross-talk signaling mechanisms in the regulation of gene expression.

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