concentration ratio

4-Hydroxyantipyrine is formed during oxidative deamination of aminopyrine.

MitoA is a ratiometric mass spectrometry probe that can be used for assessing changes in H2S within mitochondria in vivo. MitoA contains a triphenylphosphonium cation component that drives its accumulation in mitochondria where its aryl azide moiety selectively reacts with H2S to produce an amine product, MitoN. Quantifying the MitoN/MitoA ratio by LC-MS/MS reflects the mitochondrial matrix H2S concentration. In a mouse model of acute myocardial infarction with MitoA administered prior to ischemia, the MitoN/MitoA ratio is increased only in the region of ischemia.

PKM2 activator 3 is a highly potent compound that activates PKM2, with an AC 50 value of 90 nM. It exhibits excellent Caco-2 permeability, a low efflux ratio, and remarkable microsomal stability. PKM2 activator 3 is particularly valuable for anticancer research purposes [1]. (AC 50: the concentration at which 50% enzyme activation occurs.)

11-Dehydrocorticosterone is an endogenous mineralocorticoid. It increases Na+/K+-ATPase mRNA expression in vascular smooth muscle cells and inhibits aldosterone action in B. marinus toad bladder tissue in a concentration-dependent manner. 11-Dehydrocorticosterone decreases the sodium/creatine ratio and increases the potassium/creatine ratio in rat urine in a dose-dependent manner in a model of 11β-hydroxysteroid dehydrogenase inhibition induced by carbenoxolone. Chronic administration 11-dehydrocorticosterone increases plasma glucocorticoids levels, body weight gain, and adiposity, as well as induces insulin resistance in mice.

α-Synuclein inhibitor 4 (compound 3gh) is a highly effective, blood-brain barrier-permeable inhibitor of α-Synuclein aggregation, demonstrating potent activity with an IC50 value of 0.98 μM and an inhibition ratio of 91.2% at 30 μM [1].

This novel compound is an orally bioavailable antagonist of P2X3/P2X2/3 receptors, exhibiting potent activity with a pIC50 of 8 in both human and rat, and a pIC50 of 7.3 specifically for the human P2X2/3 receptor. It demonstrates high brain penetration, evidenced by a brain to plasma ratio of 6, and effectively blocks agonist-evoked intracellular Ca2+ flux and inward currents within the nanomolar range (10 nM to 1 µM) in cell lines that express human P2X3 and P2X2/3 receptors recombinantly. The compound also shows favorable pharmacokinetic properties, with a half-life (t1/2) of 1.63 hours and a time to reach maximum concentration (Tmax) of 30 minutes.

This novel compound is an orally bioavailable antagonist of P2X3/P2X2/3 receptors, exhibiting potent activity with a pIC50 of 8 in both human and rat, and a pIC50 of 7.3 specifically for the human P2X2/3 receptor. It demonstrates high brain penetration, evidenced by a brain to plasma ratio of 6, and effectively blocks agonist-evoked intracellular Ca2+ flux and inward currents within the nanomolar range (10 nM to 1 µM) in cell lines that express human P2X3 and P2X2/3 receptors recombinantly. The compound also shows favorable pharmacokinetic properties, with a half-life (t1/2) of 1.63 hours and a time to reach maximum concentration (Tmax) of 30 minutes.

The growth factors, platelet-derived growth factor (PDGF) and basic fibroblast growth factor (bFGF) play major roles in enhanced smooth muscle cells growth in rodent blood vessels after vascular injury. Tyrosine kinase inhibition has been shown to be effective in blocking tyrosine phosphorylation at the PDGF and bFGF receptors in cultured fibroblast and vascular smooth muscle cells which in turn inhibits their proliferation[1]. CGP 53716 is a specific PDGFR tyrosine kinase inhibitor on SMC (smooth muscle cell) proliferation and migration in vitro and in neointimal formationin vivo[3]. CGP 53716 inhibited serum-induced cell growth in RASMC (rat aortic smooth muscle cells). And it completely blocked PDGF-BB tyrosine receptor autophosphorylation in RASMC and 3T3 cells, PDGF-BB-induced phosphorylation of mitogen-activated protein kinase at 1 μM in RASMC and inhibited PDGF-BB-induced c-Fos protein expression at 1 μM in RASMC; consistent with inhibition of PDGF-BB-induced DNA synthesis. Further, CGP 53716 inhibited PDGF-BB-, bFGF- and EGF-induced DNA synthesis in a concentration-dependent manner in each cell line. And it showed a 2- to 4-fold selectivity for PDGF-BB-stimulated DNA synthesis over bFGF or EGF in RASMC or 3T3 cells[1]. CGP 53716 inhibited dose dependently tyrosine phosphorylation of both the known PDGFRs: the PDGFR-α and PDGFR-β. After rat carotid artery ballooning injuryin vivo, the migration of alpha-actin-positive cells on the luminal side of internal elastic lamina was decreased with 50 mg/kg/day of CGP 53716 from 38 ± 10 (control group) to 4 ± 2. Intima/media ratio was inhibited by 40% after 14 days in the CGP 53716-treated group (P=0.028) after rat aortic denudation[3].

Sterculic acid methyl ester, an ester derivative of sterculic acid known for inhibiting Δ9 desaturase, has been found to adversely affect and exhibit toxicity towards R. opacus bacteria at a concentration of 0.75 mM. It not only hampers bacterial growth but also modifies fatty acid composition by reducing stearate and oleate levels, increasing the palmitate ratio, and decreasing overall fatty acid content at 0.25 or 0.5 mM concentrations. Additionally, at 50 ppm, Sterculic acid methyl ester enhances the tumor growth-promoting effects of aflatoxin Q1 in rainbow trout, indicating a synergistic interaction between the two compounds. [Matreya, LLC. Catalog No. 1236]

Arsthinol is an antiprotozoal agent which may have anti-cancer activity. It was found that arsthinol, a trivalent organoarsenic compound (dithiarsolane), has been active in vitro on leukemia cell lines and offers a better therapeutic index than arsenic trioxide, as estimated by the ratio LD50/IC50. Arsthinol induced growth inhibition of NB4 cells at lower concentration (IC50 (concentration inhibiting growth by 50%) = 0.78 +/- 0.08 micromol/l after 24 h) than As(2)O(3) (IC50 = 1.60 +/- 0.23 micromol/l after 24 h) or melarsoprol (IC50 = 1.44 +/- 0.08 micromol/l after 24 h). Arsthinol-cyclodextrin complex demonstrated to have was more effective than arsenic trioxide (As2O3) and melarsoprol on the U87 MG cell line. Importantly, in the in vivo study, significant antitumor activity against heterotopic xenografts was observed after i.p. administration.

Sphingosines are long-chain base precursors of cellular sphingolipids used directly in the synthesis of ceramide, which in combination with sialic acid forms ganglioside. Sphingosine can exist in four stereoisomers, however only sphingosine occurs naturally. Compared to other sphingolipids throughout the body, which are predominantly composed of C-18 sphingosine, only central nervous system (CNS) gangliosides contain significant amounts of sphingosine. The concentration of sphingosine within mammalian brain gangliosides apparently increases with developmental maturation. Furthermore, the ratio of C-18 to C-20 sphingosine in the brain is thought to be related to some nervous system degeneration processes.

MitoP is a phenol product produced by the reaction of H2O2 with the ratiometric mass spectrometry probe MitoB . MitoB contains a triphenylphosphonium cation component that drives its accumulation in mitochondria where its arylboronic moiety selectively reacts with H2O2 to produce MitoP. Quantifying the MitoP/MitoB ratio by LC-MS/MS reflects the mitochondrial matrix H2O2 concentration.