Search results for "Guanidine"
showing 10 items of 78 documents
Human ABCB1 confers cells resistance to cytotoxic guanidine alkaloids from Pterogyne nitens.
2015
Multidrug resistance (MDR) caused by human ABCB1 (P-glycoprotein/MDR1) is one of the major obstacles in chemotherapy. To understand the mechanism of MDR by ABCB1 and circumvent the MDR, in the present study, we established human ABCB1-expressing cells (Flp-In-293/ABCB1 cells) and examined the cytotoxic effects of four guanidine alkaloids from Pterogyne nitens (galegine, nitensidine A, pterogynidine and pterogynine) using Flp-In-293/Mock and Flp-In-293/ABCB1 cells. The activity of ABCB1 in Flp-In-293/ABCB1 cells were confirmed by typical substrates for ABCB1 (taxol and vinblastine) in MTT assay. Flp-In-293/ABCB1 cells were also resistant to the four guanidine alkaloids as well as taxol and v…
Nitensidine A, a guanidine alkaloid from Pterogyne nitens, is a novel substrate for human ABC transporter ABCB1.
2014
The Pterogyne nitens (Fabaceae) tree, native to South America, has been found to produce guanidine alkaloids as well as bioactive flavonols such as kaempferol, quercetin, and rutin. In the present study, we examined the possibility of interaction between human ATP-binding cassette (ABC) transporter ABCB1 and four guanidine alkaloids isolated from P. nitens (i.e., galegine, nitensidine A, pterogynidine, and pterogynine) using human T cell lymphoblast-like leukemia cell line CCRF-CEM and its multi-drug resistant (MDR) counterpart CEM/ADR5000. In XTT assays, CEM/ADR5000 cells were resistant to the four guanidine alkaloids compared to CCRF-CEM cells, although the four guanidine alkaloids exhibi…
Effects of Some Guanidino Compounds on Human Cerebral Arteries
1999
Background and Purpose —Accumulation of endogenous guanidino-substituted analogues of l -arginine in chronic renal failure might contribute to some of the vascular and neurological disorders of this pathology. We tested the hypothesis that in human cerebral arteries, some guanidino compounds may increase vascular tone, through nitric oxide (NO) synthase inhibition, and impair endothelium-dependent relaxation. Methods —Rings of human middle cerebral artery were obtained during autopsy of 26 patients who had died 3 to 12 hours before. The rings were suspended in organ baths for isometric recording of tension. We then studied the responses to N G -monomethyl- l -arginine (L-NMMA), N G , N G -…
Contractile effects of arginine analogues on human internal thoracic and radial arteries
2000
Abstract Objectives: Plasma levels of endogenous guanidino-substituted analogues of L -arginine are increased in various pathologic conditions. In the present study we determined the effects of some of these compounds on basal and stimulated release of nitric oxide in human internal thoracic and radial arteries. Methods: Rings of human internal thoracic and radial arteries were obtained from 16 multiorgan donors. The rings were suspended in organ baths for isometric recording of tension. Results: N G -monomethyl L -arginine (10 –6 to 10 –3 mol/L) and N G ,N G -dimethyl L -arginine (10 –6 to 10 –3 mol/L) caused concentration- and endothelium-dependent contractions. Maximal force of contracti…
Dose escalating safety study of CNS 5161 HCl, a new neuronal glutamate receptor antagonist (NMDA) for the treatment of neuropathic pain
2007
What is already known about this subject • Despite encouraging effects of N-methyl-D-aspartate (NMDA) receptor antagonists in reducing neuropathic pain of different aetiologies, the clinical use of these agents has been limited by their mainly psychotropic side-effects. • In a recent study in healthy volunteers, CNS 5161, a novel noncompetetive NMDA receptor antagonist, was well tolerated up to a dosage of 2000 µg without psychotropic side-effects. • This is the first study to evaluate the maximal tolerated dosage of CNS 5161 and to gain experience about the analgesic effect of CNS 5161 in patients with different pain syndromes. What this study adds • In patients with neuropathic pain CNS 5…
Dual Diagnostic Role of 123I-MIBG Scintigraphy in Inverted-Takotsubo Pattern Cardiomyopathy
2015
We highlight the dual role of I-MIBG scintigraphy in inverted-Takotsubo pattern cardiomyopathy, the diagnosis of which is sometimes challenging: Firstly, I-MIBG scintigraphy can show myocardial sympathetic dysfunction (low I-MIBG uptake) in the hypokinetic basal segments, sparing the left ventricle apex. It is helpful in the imaging diagnosis of inverted-Takotsubo pattern cardiomyopathy and confirms that acute dysfunction of myocardial sympathetic nerve endings occurs with this cardiomyopathy. Secondly, I-MIBG scintigraphy is an accurate imaging examination to detect and localize pheochromocytoma; it can help in the search for an endogenous cause of this adrenergic stress-related cardiomyop…
Myocardial 123metaiodobenzylguanidine uptake in genetic Parkinson's disease.
2008
Myocardial (123)Metaiodobenzylguanidine (MIBG) enables the assessment of postganglionic sympathetic cardiac innervation. MIBG uptake is decreased in nearly all patients with Parkinson's disease (PD). Our objective was to evaluate MIBG uptake in patients with genetic PD. We investigated MIBG uptake in 14 patients with PD associated with mutations in different genes (Parkin, DJ-1, PINK], and leucine-rich repeat kinase 2 -LRRK2), in 15 patients with idiopathic PD, and 10 control subjects. The myocardial MIGB uptake was preserved in 3 of the 4 Parkin-associated Parkinsonisms, in I of the 2 patients with DJ-1 mutations, in 1 of the 2 brothers with PINK] mutations, in 3 of the 6 unrelated patient…
Comparison of131I-metaiodobenzylguanidine scintigraphy with urinary and plasma catecholamine determinations in the diagnosis of pheochromocytoma
1985
In a retrospective study of 31 patients with suspected pheochromocytoma we examined the preoperative results of 131I-metaiodobenzylguanidine (131-I-MIBG) scintigraphy and a fluorimetric urine catecholamine determination test. An additional radioenzymatic plasma catecholamine determination test was performed in 25 patients. In 14 of the 31 patients the diagnosis of pheochromocytoma was later histologically confirmed. In the remaining 17 patients the suspected diagnosis was finally rejected after a clinical decision had been made on the basis of clinical history, symptoms, laboratory and imaging tests. 131-I-MIBG scintigraphy apparently had a very high specificity (no false-positive results a…
Cardioprotective Effects of the Na + /H + Exchange Inhibitor Cariporide in Patients With Acute Anterior Myocardial Infarction Undergoing Direct PTCA
2000
Background —Activation of Na + /H + exchange in myocardial ischemia and/or reperfusion leads to calcium overload and myocardial injury. Experimental studies have shown that Na + /H + exchange inhibitors can attenuate Ca 2+ influx into cardiomyocytes. We therefore performed a multicenter, randomized, placebo-controlled clinical trial to test the hypothesis that inhibition of Na + /H + exchange limits infarct size and improves myocardial function in patients with acute anterior myocardial infarction (MI) treated with direct PTCA. Methods and Results —One hundred patients were randomized to receive placebo (n=51) or a 40-mg intravenous bolus of the Na + /H + exchange inhibitor cariporide (HOE…
Darstellung und H2-agonistische Aktivität alkylsubstituierter 3-(Imidazol-4-yl)propylguanidine Synthesis and H2-Agonistic Activity of Alkyl-3-(imidaz…
1987
Derivate des 3-(Imidazol-4-yl)propylguanidins mit einem Methyl- oder einem 2-(Ethylthio)ethyl-Substituenten2) an der Guanidin-Gruppe weisen am H2-Rezeptor des Meerschweinchenvorhofs nur 10–20% der Histaminaktivitat auf. Dagegen fuhrt die Substitution mit der H2-affinen 2-[(5-Methylimidazol-4-yl) methylthio]ethyl-Gruppierung zu Impromidin, einem hochpotenten H2-Agonisten.