scholarly journals Spectroscopic, radiochemical, and theoretical studies of the Ga3+-N-2-hydroxyethyl piperazine-N′-2-ethanesulfonic acid (HEPES buffer) system: evidence for the formation of Ga3+- HEPES complexes in68 Ga labeling reactions

2013 ◽  
Vol 8 (3) ◽  
pp. 265-273 ◽  
Author(s):  
André F. Martins ◽  
M. I. M. Prata ◽  
S. P. J. Rodrigues ◽  
Carlos F. G. C. Geraldes ◽  
P. J. Riss ◽  
...  
Keyword(s):  
Buffer System ◽  
Theoretical Studies ◽  
Hepes Buffer ◽  
Ethanesulfonic Acid ◽  
Hydroxyethyl Piperazine

scholarly journals The use of HEPES-buffer in the production of gallium-68 radiopharmaceuticals – time to reconsider strict pharmacopoeial limits?

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Jannie le Roux ◽  
Janke Kleynhans ◽  
Sietske Rubow
Keyword(s):  
Intravenous Infusion ◽  
Short Communication ◽  
Drug Formulation ◽  
Hepes Buffer ◽  
Beneficial Effects ◽  
Molar Activity ◽  
Ethanesulfonic Acid ◽  
Gallium 68 ◽  
Review Current ◽  
Hydroxyethyl Piperazine

AbstractHEPES (4-(2-hydroxyethyl) piperazine-1-ethanesulfonic acid) is a buffer that is used in the radiolabelling of gallium-68 compounds. The beneficial effects of HEPES on molar activity in bioconjugates have been well described. Current strict regulations on the HEPES content in radiopharmaceuticals limit its use when intended for parenteral administration.This short communication summarizes data from the literature on the toxicity of HEPES in dogs after intravenous infusion and the subsequent use in humans. We also highlight the use of HEPES in an FDA labelled intravenous drug formulation. Regulatory institutions may consider this data to review current strict limits.

The Effects of Hepes Buffer on Clotting Tests, Assay of Factors V and VIII and on the Hydrolysis of Esters by Thrombin and Thrombokinase

1976 ◽  
Vol 35 (01) ◽  
pp. 202-210 ◽  
Author(s):  
Phyllis S. Roberts ◽  
Haywood N. Hughes ◽  
Patricia B. Fleming
Keyword(s):  
Ionic Strength ◽  
Human Plasma ◽  
Inhibitory Effect ◽  
Clotting Factors ◽  
Bovine Thrombin ◽  
Hepes Buffer ◽  
Human Thrombin ◽  
Ethanesulfonic Acid ◽  
Hydrolysis Of Esters ◽  
Hydrolysis Of

SummaryShorter clotting times were found in the presence of 50 mM Hepes (N-2-hydroxyethylpiper-azine-N1-2-ethanesulfonic acid) buffer than of 50 mM Imidazole buffer in one-stage assays of factors V and VIII, in modified APTT and PT tests and in tests of the clotting of human plasma by purified human thrombin. All tests were performed at ionic strength 0.155 in the presence of either Hepes. NaOH or Imidazole. HC1 buffer, pH 7.4 at 37°. The faster clotting in the presence of Hepes buffer, therefore, is probably due, at least in part, to acceleration by Hepes of thrombin’s enzymatic action on fibrinogen and/or of the polymerization of the fibrin monomers.Hepes may also have effects on other blood clotting reactions. Rates of hydrolysis of TAME or BAME (p-toluenesulfonyl-or benzoyl-L-arginine methyl ester) at pH 7.4, 37° by purified human or bovine thrombin were essentially the same in 200 mM Hepes as in 250 mM Tris. HQ buffer (rates in Hepes. NaOH or Hepes. KOH buffers were compared with those in Tris. HQ plus NaCl for KC1). However, with purified bovine thrombokinase, rates of TAME hydrolysis in Hepes buffer were accelerated and rates of BAME hydrolysis slightly inhibited. Hepes, therefore, reacts with thrombokinase but whether this accelerates (or inhibits) the rate of converting prothrombin to thrombin remains to be determined. In addition, Hepes has an inhibitory effect on clotting since increasing the concentration of Hepes from 50 mM to 200 mM inhibits clotting in the PT, APTT and bovine thrombin-human plasma tests.Hepes buffer is being added to some plasmas and to some reagents used in clotting tests. It is, therefore, important to realize that its concentration must be monitored closely or erroneous results may be obtained in clotting tests and assays of clotting factors.The clotting times were the same in the presence of 50 mM Tris. HC1 as in Imidazole. HC1 buffers in APTT tests at three ionic strengths but they differed slightly in plasma-thrombin tests. Depending upon the ionic strength, 17 mM Barbital Sodium. HC1 buffer inhibited APTT tests but accelerated plasma-thrombin tests. All the buffers tested, therefore, have individual effects on the clotting tests.

Dissociation between positive inotropic and alkalinizing effects of angiotensin II in feline myocardium

1997 ◽  
Vol 272 (3) ◽  
pp. H1131-H1136 ◽  
Author(s):  
A. Mattiazzi ◽  
N. G. Perez ◽  
M. G. Vila-Petroff ◽  
B. Alvarez ◽  
M. C. Camilion de Hurtado ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Simultaneous Measurement ◽  
Myocardial Contractility ◽  
Positive Inotropic Effect ◽  
Inotropic Effect ◽  
Papillary Muscles ◽  
Ang Ii ◽  
Acetoxymethyl Ester ◽  
Hepes Buffer ◽  
Ethanesulfonic Acid

The present study examines the intracellular pH (pHi) dependence of angiotensin (ANG) II-induced positive inotropic effect in cat papillary muscles contracting isometrically (0.2 Hz, 30 degrees C). Muscles were loaded with the fluorescent dye 2'-7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein acetoxymethyl ester for simultaneous measurement of pHi and contractility. In N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES) buffer (n = 4), there was a temporal dissociation between the positive inotropic and the alkalinizing effects of ANG II (0.5 microM). The positive inotropic effect of ANG II peaked at 9.7 +/- 0.8 min (240 +/- 57% above control) without significant changes in pHi. The increase in pHi became significant (0.05 +/- 0.01 pH units) only after 16 min of exposure to the drug, when the positive inotropic effect of ANG II was already fading. In HCO3- buffer (n = 7), the ANG II-induced positive inotropic effect occurred without significant pHi changes. In the presence of 5 microM ethyl isopropyl amiloride (EIPA, to specifically inhibit the Na+/H+ exchanger), the alkalinizing effect of ANG II was changed to a significant decrease in pHi, despite which ANG II still increased contractility by 87 +/- 16% (n = 6). The results indicate that in HEPES buffer only a fraction of the ANG II-induced positive inotropic effect can be attributed to a pHi change, whereas in a physiological CO2-HCO3- medium the positive inotropic effect of ANG II is independent of pHi changes. Furthermore, an ANG II-induced increase in myocardial contractility was observed even when ANG II administration elicited a decrease in pHi, as occurred after Na+/H+ exchanger blockade. The results show that in feline myocardium, the increase in contractility evoked by ANG II in a physiological CO2-HCO3- medium is not due to an increase in Ca2+ myofilament sensitivity secondary to an increase in myocardial pHi.

scholarly journals Optimization of Enzyme Dilution Buffer and Reaction Buffer for Vaccinia H-1 Related Wild Enzyme Assay and Its Stability at 4°C

2015 ◽  
Vol 15 (2) ◽  
pp. 117-122
Author(s):  
Deegendra Khadka
Keyword(s):  
Therapeutic Target ◽  
Protein Concentration ◽  
Enzyme Assay ◽  
Specific Activity ◽  
Enzyme Stability ◽  
Telomerase Activity ◽  
Buffer System ◽  
Promising Therapeutic Target ◽  
Ethanesulfonic Acid ◽  
The Stability

A human dual specific phosphates (DUSP), Vaccinia H-1 related wild enzyme (VHR), dephosphorylates both phosphotyrosine and phosphoserine/phosphothreonine residue of a protein. VHR is considered as a promising therapeutic target for cancer because the cells lacking VHR are arrested at the G1-S and G2-M transitions of the cell cycle with a decreased telomerase activity. VHR being a therapeutic target for cancer is crucial to know about its stability and its assay procedure conditions. This study was conducted to verify the viability of VHR enzyme at 4°C. Protein concentration and specific activity were calculated from Bradford method and p-nitrophenylphosphate (pNPP) assay by measuring the absorbance at 595 nm and 405 nm respectively in each respective day. The absorbance showed invariable difference in protein concentration and specific activity from starting to final days. Buffers like enzyme dilution and reaction buffers played significant role in VHR enzyme stability and activity. To find out the correct buffer components for carrying out the VHR enzyme assay, several experiments were carried out by using variable constituents in enzyme dilution buffer and reaction buffer. The present study revealed that 3- component buffer system without thiol i.e. Dithiothreitol (DTT) or β-Mercaptoethanol (β-ME) as a reaction buffer and 2-N-morpholino ethanesulfonic acid (MES) buffer with DTT as an enzyme dilution buffer demonstrated invariably different in the stability throughout the experiment.DOI: http://dx.doi.org/njst.v15i2.12127Nepal Journal of Science and Technology Vol. 15, No.2 (2014) 117-122

Negative Cardiac Inotropic Effects of Calcium Ion and of N-2-Hydroxyethylpiperazine-N′-2-ethanesulfonic Acid (HEPES) Buffer at Normal and Low Sodium Concentration

1974 ◽  
Vol 52 (5) ◽  
pp. 1025-1029 ◽  
Author(s):  
Peter E. Dresel
Keyword(s):  
Calcium Ions ◽  
Calcium Ion ◽  
Negative Inotropic Effect ◽  
Sodium Concentration ◽  
Contractile Force ◽  
Inotropic Effects ◽  
Hepes Buffer ◽  
Low Sodium ◽  
Ethanesulfonic Acid ◽  
Krebs Buffer

Isolated electrically driven left atria from rabbits were suspended in N-2-hydroxyethylpiperazine-N′-2-ethanesulfonic acid (HEPES) buffer and exposed to increasing concentration of calcium ions in the presence of different concentrations of sodium. Maximal contractile force occurred at 10 mM Ca and 145 mM Na. Higher concentrations of Ca had a negative inotropic effect. Lowering the Na concentration decreases the concentration of Ca required to observe the negative inotropy, until at 60–70 mM Na, it occurred at 5 mM Ca. This last result was confirmed in Krebs–Henseleit solution. Contractility at low Na and/or Ca media was less in HEPES than in Krebs buffer.

scholarly journals Buffer Standards for pH Measurement of N-(2-Hydroxyethyl)piperazine-N′-2-ethanesulfonic Acid (HEPES) for I=0.16 mol⋅kg−1 from 5 to 55 °C

2009 ◽  
Vol 38 (4) ◽  
pp. 449-458 ◽  
Author(s):  
Rabindra N. Roy ◽  
Lakshmi N. Roy ◽  
Shahaf Ashkenazi ◽  
Joshua T. Wollen ◽  
Craig D. Dunseth ◽  
...  
Keyword(s):  
Ph Measurement ◽  
Ethanesulfonic Acid ◽  
Hydroxyethyl Piperazine

scholarly journals Effects of Andrographolide on Intracellular pH Regulation, Cellular Migration, and Apoptosis in Human Cervical Cancer Cells (Running Tittle: Effects of Andrographolide on pH Regulators and Apoptosis in Cervical Cancer)

Cancers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 387
Author(s):  
Shih-Hurng Loh ◽  
Yi-Ting Tsai ◽  
Shu-Fu Huang ◽  
Tien-Chieh Yu ◽  
Pei-Chun Kuo ◽  
...  
Keyword(s):  
Cervical Cancer ◽  
Cancer Cells ◽  
Intracellular Ph ◽  
Ph Regulation ◽  
Cellular Migration ◽  
Cervical Cancer Cells ◽  
Ethanesulfonic Acid ◽  
Human Cervical Cancer Cells ◽  
Hydroxyethyl Piperazine ◽  
Human Cervical Cancer

Cancer cells have been characterized with alkaline intracellular pH (pHi) values (≥7.2) to enable cancer proliferation, migration, and progression. The aim of the present study was to explore the concentration-dependent effects of Andrographolide, an active diterpenoid compound of herb Andrographis paniculata, on Na+/H+ exchanger isoform 1 (NHE1), cellular migration and apoptosis in human cervical cancer cells (HeLa). The pHi was detected by microspectrofluorometry method, and intracellular acidification was induced by NH4Cl prepulse technique. Viability and protein expression were determined by MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and Western blot, respectively. Human normal endocervical cells (End1), ectocervical cells (Ect1), and HeLa were bought commercially. The resting pHi value of HeLa (≈7.47) was significantly higher than that of End1 and Ect1 (≈7.30), and shifted from alkaline to acidic following acid/base impacts. In HEPES (4-(2-Hydroxyethyl)piperazine-1-ethanesulfonic acid | N-(2-Hydroxyethyl)piperazine-N′-(2-ethanesulfonic acid) -buffered superfusate, NHE1 and V-ATPase co-existed functionally for acid extrusion in HeLa, while only NHE1 existed functionally in End/Ect1. Andrographolide (3–1000 μM) concentration-dependently inhibited NHE1 activity. Cell-migration and expressions of NHE1, V-ATPase, PARP (poly-ADP-ribose-polymerase), pro-Caspase-3, and Bcl-2 were significantly reduced by pretreating with Andrographolide (≥100 μM) for 24–48 h in HeLa. Andrographolide inhibited cell viability of End1-cells/Ect1 and HeLa (≥100 and ≥30 μM, respectively). The present findings implicate the promising clinical applications of Andrographolide on cervical cancer treatment.

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