Complexation Equilibria and Fluorescent Properties of Chelating Reagents Derived from Ethylene Glycol Bis(β-aminoethylether)-N,N,N′,N′-tetraacetic Acid

1993 ◽  
Vol 66 (11) ◽  
pp. 3377-3381 ◽  
Author(s):  
Akio Yuchi ◽  
Atsushi Tanaka ◽  
Manabu Hirai ◽  
Takashi Yasui ◽  
Hiroko Wada ◽  
...  
Keyword(s):  
Ethylene Glycol ◽  
Tetraacetic Acid ◽  
Fluorescent Properties ◽  
Complexation Equilibria ◽  
Chelating Reagents

Fluorine-doped carbon nitride quantum dots: Ethylene glycol-assisted synthesis, fluorescent properties, and their application for bacterial imaging

Carbon ◽  
2016 ◽  
Vol 109 ◽  
pp. 141-148 ◽  
Author(s):  
Nan Wang ◽  
Hai Fan ◽  
Jianchao Sun ◽  
Zhenwei Han ◽  
Jing Dong ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Ethylene Glycol ◽  
Carbon Nitride ◽  
Fluorescent Properties

Phospholipase A2 activation in human neutrophils requires influx of extracellular Ca2+ and leukotriene B4

1995 ◽  
Vol 268 (1) ◽  
pp. C138-C146 ◽  
Author(s):  
S. Reddy ◽  
R. Bose ◽  
G. H. Rao ◽  
M. Murthy
Keyword(s):  
Ethylene Glycol ◽  
Phospholipase A2 ◽  
Platelet Activating Factor ◽  
Leukotriene B4 ◽  
Lipid Mediators ◽  
Oxidation Products ◽  
Human Neutrophils ◽  
Tetraacetic Acid ◽  
A 23187 ◽  
Transient Elevation

We have demonstrated that phospolipase A2 (PLA2) activation in human neutrophils requires both the influx of extracellular Ca2+ and leukotriene B4 (LTB4). Surprisingly, the eicosanoids (LTB4 and its omega-oxidation products) formed were quantitatively very similar in both thapsigargin (Thap)- and A-23187-stimulated neutrophils. In contrast, Thap had very little effect on the activation of PLA2 when 5-lipoxygenase (5-LO) was blocked by BW755C or MK-886, whereas A-23187 caused a substantial activation. The lack of PLA2 activation in Thap-stimulated neutrophils results from the inhibition of LTB4 formation in the presence of 5-LO inhibitors. It appears that A-23187 activates both LTB4-dependent and -independent PLA2, whereas Thap activates LTB4-dependent PLA2. Experiments with ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid demonstrated that activation of Thap-sensitive PLA2 and 5-LO requires the influx of Ca2+. Neither the transient elevation of cytosolic Ca2+ from intracellular stores nor the sustained Ca2+ influx alone without LTB4 appears sufficient to cause the activation of LTB4-dependent PLA2. We suggest that the activation of LTB4-dependent PLA2 involves 1) a sustained elevation of cytosolic Ca2+ coupled to the influx of extracellular Ca2+ and 2) a coupling between LTB4 and its receptor. We conclude that LTB4-dependent PLA2 plays an important role in the poststimulatory formation of lipid mediators such as prostaglandins, leukotrienes, and platelet-activating factor.

cAMP-stimulated rise of [Ca2+]i in rabbit connecting tubules: role of peritubular Ca

1990 ◽  
Vol 258 (3) ◽  
pp. F751-F755 ◽  
Author(s):  
J. E. Bourdeau ◽  
B. K. Eby
Keyword(s):  
Parathyroid Hormone ◽  
Ethylene Glycol ◽  
Cell Activation ◽  
Proximal Tubules ◽  
Tetraacetic Acid ◽  
Luminal Membrane ◽  
Dose Dependent Fashion ◽  
Dose Dependent

Parathyroid hormone (PTH) increases cytosolic free Ca concentration ([ Ca2+]i) by mechanisms that depend on extracellular Ca in both cultured renal proximal tubules and isolated rabbit connecting tubules (CNTs). In CNTs 8-bromoadenosine 3',5'-cyclic monophosphate (8-BrcAMP) mimics this action, implicating cAMP as a second messenger, and part of the rise, due to increased luminal membrane Ca entry, is likely related to Ca absorption. In cultured proximal tubules the rise in [Ca2+]i, presumably mediated by increased Ca entry across the basolateral plasmalemma, activates gluconeogenesis and shortens microvilli. In the present study we examined cAMP-mediated Ca entry across the basolateral membranes of CNT cells, an effect potentially related to cell activation. Single CNTs were dissected from rabbit kidneys and loaded with fura-2. [Ca2+]i was measured by dual-wavelength excitation during perfusion of isolated segments in vitro. With 1.8 or 2.0 mM Ca in the lumen and the bath, suffusate 8-BrcAMP increased [Ca2+]i within minutes in a dose-dependent fashion. The increase persisted as long as 8-BrcAMP was present and reversed on its withdrawal. With 0.1 microM Ca in the lumen and the bath, 8-BrcAMP, but not ionomycin, failed to increase [Ca2+]i, implying that extracellular Ca is the major source. In tubules perfused with 2 mM ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid to eliminate luminal Ca, but suffused with 1.8 or 2.0 mM Ca, 8-BrcAMP increased [Ca2+]i (though less so than with Ca in the lumen), implying Ca entry across basolateral cell membranes. This rise in [Ca2+]i was attenuated markedly by the presence of 50 microM LaCl3 in the bath.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of external ions on 45Ca efflux from cat intestinal muscle

1980 ◽  
Vol 238 (6) ◽  
pp. G520-G525
Author(s):  
B. A. Curtis ◽  
D. Kreulen ◽  
C. L. Prosser
Keyword(s):  
Smooth Muscle ◽  
Small Intestine ◽  
Electrical Stimulation ◽  
Membrane Potential ◽  
Ethylene Glycol ◽  
Resting Membrane Potential ◽  
Krebs Solution ◽  
Tetraacetic Acid ◽  
Circular Smooth Muscle ◽  
45Ca Efflux

The surface-bound Ca of isolated circular smooth muscle of cat small intestine can be removed by substitution of LiCl for NaCl in Krebs solution. This substitution removed surface-bound Ca (45Ca) and allowed us to study transmembrane 45Ca efflux. Neither the resting membrane potential nor contractility changed when Li was substituted for Na. Li removed the same extracellular 45Ca store as did ethylene glycol-bis-(beta-aminoethylether)-N,N'-tetraacetic acid. The resting transmembrane 45Ca efflux was inhibited by La3+ and was unchanged in Li, tris(hydroxymethyl)aminomethane, arginine, and sucrose Krebs solution. The extra 45Ca efflux observed upon electrical stimulation was no greater in Na-Krebs than Li-Krebs, but during response to acetylcholine the extra 45Ca efflux was greater in Na-Krebs than Li-Krebs. We conclude that the surface-bound Ca is sensitive to external Na and that the transmembrane Ca efflux is not completely dependent on external Na.

EGTA-induced disruption of epithelial cell tight junctions in the lactating caprine mammary gland

1995 ◽  
Vol 269 (4) ◽  
pp. R848-R855 ◽  
Author(s):  
K. Stelwagen ◽  
V. C. Farr ◽  
S. R. Davis ◽  
C. G. Prosser
Keyword(s):  
Blood Flow ◽  
Mammary Gland ◽  
Epithelial Cell ◽  
Ethylene Glycol ◽  
Tight Junctions ◽  
Evans Blue ◽  
Sucrose Solution ◽  
Milk Secretion ◽  
Tetraacetic Acid

The suitability of the Ca2+ chelator ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) to induce disruption of mammary tight junctions (TJ) and its effect on milk secretion were investigated in six goats. EGTA was administered via the teat of one gland as an isosmotic (300 mosmol/l) K-EGTA solution (68 mM EGTA), whereas the control gland received an isosmotic sucrose solution. Lactose, Na, K, and Cl in milk, blood lactose, and the presence of Evans blue (EB) in mammary lymph were used as indicators of TJ disruption. EGTA caused transient (approximately 60 h) changes (P < 0.05) in the concentration of lactose, K, Na, and Cl in milk, consistent with loss of TJ integrity. This was confirmed by a rapid (< 1 h) increase (P < 0.05) in blood lactose levels. Moreover, EB appeared in lymph < 1 h after EGTA+EB treatment. Milk secretion declined unilaterally by 15% (P < 0.05) after EGTA and did not return to baseline until approximately 60 h after EGTA. EGTA caused a unilateral, temporary (first 7 h) increase in mammary blood flow. This study shows that a rapid temporary disruption of mammary TJ can be successfully induced in vivo and that such disruption compromises milk secretion.

scholarly journals MoS2 QDs/8-Armed Poly(Ethylene Glycol) Fluorescence Sensor for Three Nitrotoluenes (TNT) Detection

Biosensors ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 475
Author(s):  
Xiaoyuan Zhang ◽  
Zhiqiang Su
Keyword(s):  
Quantum Dots ◽  
Polyethylene Glycol ◽  
Detection Limit ◽  
Ethylene Glycol ◽  
Hydrazine Hydrate ◽  
Poly Ethylene Glycol ◽  
Fluorescent Properties ◽  
Detection Range ◽  
Poly Ethylene ◽  
Tnt Detection

In this work, ammonia cross-linked 8-armed polyethylene glycol hydrogel material was successfully synthesized and used as a template for synthesizing nanoparticles with fluorescent properties. The 8-armed polyethylene glycol hydrogel template was used to prepare molybdenum disulfide quantum dots (MoS2 QDs). The ammonium tetrathiomolybdate functioned as a molybdenum source and hydrazine hydrate functioned as a reducing agent. The fluorescence properties of the as-prepared MoS2 QDs were investigated. The bursting of fluorescence caused by adding different concentrations of explosive TNT was studied. The study indicated that the synthesized MoS2 QDs can be used for trace TNT detection with a detection limit of 6 nmol/L and a detection range of 16–700 nmol/L. Furthermore, it indicated that the fluorescence-bursting mechanism is static bursting.

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