The Experts below are selected from a list of 192 Experts worldwide ranked by ideXlab platform
J M Bone - One of the best experts on this subject based on the ideXlab platform.
-
urinary Catecholamine excretion in relation to renal function
Annals of Clinical Biochemistry, 1999Co-Authors: N B Roberts, John Dutton, P Mcclelland, J M BoneAbstract:The urinary excretions of the free Catecholamines noradrenaline, adrenaline and dopamine were measured in 50 patients (33 men and 17 women) with chronic renal failure. Stability studies showed that the Catecholamines were stable in unacidified urine as long as the pH was not greater than 7.5 and the urine was acidified within 2-3 h of collection. The outputs of noradrenaline and dopamine correlated positively with creatinine clearance and in patients with clearances above 40 mL/min were similar to those in healthy volunteers (n = 20). However, adrenaline output was not correlated with creatinine clearance although it was lower in patients with renal failure compared with healthy volunteers. The urinary free Catecholamine output during the first 10 days after a renal transplant was significantly less than normal, presumably because renal function was still impaired. However, in patients treated with cyclosporin A (CyA) combined with prednisolone the Catecholamine excretion was lower compared with those treated with CyA and azathioprine. Impairment in renal function can have a marked effect on the output of free Catecholamines and must be borne in mind when interpreting values that may have pathological significance.
Jan Szopa - One of the best experts on this subject based on the ideXlab platform.
-
Expression of human dopamine receptor in potato (Solanum tuberosum) results in altered tuber carbon metabolism
BMC Plant Biology, 2005Co-Authors: Aleksandra Skirycz, Anna Świędrych, Jan SzopaAbstract:Background Even though the Catecholamines (dopamine, norepinephrine and epinephrine) have been detected in plants their role is poorly documented. Correlations between norepinephrine, soluble sugars and starch concentration have been recently reported for potato plants over-expressing tyrosine decarboxylase, the enzyme mediating the first step of Catecholamine synthesis. More recently norepinephrine level was shown to significantly increase after osmotic stress, abscisic acid treatment and wounding. Therefore, it is possible that Catecholamines might play a role in plant stress responses by modulating primary carbon metabolism, possibly by a mechanism similar to that in animal cells. Since to date no Catecholamine receptor has been identified in plants we transformed potato plants with a cDNA encoding human dopamine receptor (HD1). Results Tuber analysis of transgenic plants revealed changes in the activities of key enzymes mediating sucrose to starch conversion (ADP-glucose phosphorylase and sucrose synthase) and sucrose synthesis (sucrose phosphate synthase) leading to altered content of both soluble sugars and starch. Surprisingly the Catecholamine level measured in transgenic plants was significantly increased; the reason for this is as yet unknown. However the presence of the receptor affected a broader range of enzyme activities than those affected by the massive accumulation of norepinephrine reported for plants over-expressing tyrosine decarboxylase. Therefore, it is suggested that the presence of the exogenous receptor activates Catecholamine cAMP signalling in plants. Conclusions Our data support the possible involvement of Catecholamines in regulating plant carbon metabolism via cAMP signalling pathway.
-
Identification and quantification of Catecholamines in potato plants (Solanum tuberosum) by GC–MS
Phytochemistry, 2001Co-Authors: Jan Szopa, Grzegorz Wilczyński, Oliver Fiehn, Andreas Wenczel, Lothar WillmitzerAbstract:Abstract Dopamine, norepinephrine, and normetanephrine were identified by GC–MS in potato ( Solanum tuberosum L.) plants, the latter was new for plants. The highest amount of Catecholamines was found in leaves. A developmental stage dependent variation in potato leaf Catecholamines accumulation was also observed with highest level in third leaves. Catecholamine contents decrease during cold storage of tubers to undetectable levels. Mechanical wounding of leaves led to a small increase in the level of Catecholamines investigated.
N B Roberts - One of the best experts on this subject based on the ideXlab platform.
-
urinary Catecholamine excretion in relation to renal function
Annals of Clinical Biochemistry, 1999Co-Authors: N B Roberts, John Dutton, P Mcclelland, J M BoneAbstract:The urinary excretions of the free Catecholamines noradrenaline, adrenaline and dopamine were measured in 50 patients (33 men and 17 women) with chronic renal failure. Stability studies showed that the Catecholamines were stable in unacidified urine as long as the pH was not greater than 7.5 and the urine was acidified within 2-3 h of collection. The outputs of noradrenaline and dopamine correlated positively with creatinine clearance and in patients with clearances above 40 mL/min were similar to those in healthy volunteers (n = 20). However, adrenaline output was not correlated with creatinine clearance although it was lower in patients with renal failure compared with healthy volunteers. The urinary free Catecholamine output during the first 10 days after a renal transplant was significantly less than normal, presumably because renal function was still impaired. However, in patients treated with cyclosporin A (CyA) combined with prednisolone the Catecholamine excretion was lower compared with those treated with CyA and azathioprine. Impairment in renal function can have a marked effect on the output of free Catecholamines and must be borne in mind when interpreting values that may have pathological significance.
Sushil K Mahata - One of the best experts on this subject based on the ideXlab platform.
-
effect of heart failure on Catecholamine granule morphology and storage in chromaffin cells
Journal of Endocrinology, 2016Co-Authors: Sushil K Mahata, Hong Zheng, Kaushik P PatelAbstract:One of the key mechanisms involved in sympathoexcitation in chronic heart failure (HF) is the activation of the adrenal glands. Impact of the elevated Catecholamines on the hemodynamic parameters has been previously demonstrated. However, studies linking the structural effects of such overactivation with secretory performance and cell metabolism in the adrenomedullary chromaffin cells in vivo have not been previously reported. In this study, HF was induced in male Sprague-Dawley rats by ligation of the left coronary artery. Five weeks after surgery, cardiac function was assessed by ventricular hemodynamics. HF rats showed increased adrenal weight and adrenal Catecholamine levels (norepinephrine, epinephrine and dopamine) compared with sham-operated rats. Rats with HF demonstrated increased small synaptic and dense core vesicle in splanchnic–adrenal synapses indicating trans-synaptic activation of Catecholamine biosynthetic enzymes, increased endoplasmic reticulum and Golgi lumen width to meet the demand of increased Catecholamine synthesis and release, and more mitochondria with dilated cristae and glycogen to accommodate for the increased energy demand for the increased biogenesis and exocytosis of Catecholamines from the adrenal medulla. These findings suggest that increased trans-synaptic activation of the chromaffin cells within the adrenal medulla may lead to increased Catecholamines in the circulation which in turn contributes to the enhanced neurohumoral drive, providing a unique mechanistic insight for enhanced Catecholamine levels in plasma commonly observed in chronic HF condition.
Jenn Rachelle U Santos - One of the best experts on this subject based on the ideXlab platform.
-
Catecholamine induced cardiomyopathy in pheochromocytoma how to manage a rare complication in a rare disease
Hormone and Metabolic Research, 2019Co-Authors: Alessandra Brofferio, Jenn Rachelle U Santos, Bruna Viana, Karel PacakAbstract:Pheochromocytomas and paragangliomas (PHEOs) are rare neuroendocrine tumors. Clinical manifestations include different cardiovascular signs and symptoms, which are related to excessive secretion of Catecholamines. Catecholamine-induced cardiomyopathy in PHEO (CICMPP) is a rare but dreaded complication of PHEO. Once patient is diagnosed with this condition, the prognosis is worse and a surgical risk is much higher than expected. This article focuses on how Catecholamines affect the heart and the pathophysiologic mechanism of CICMPP. The cardiovascular responses to Catecholamine depend mostly on which Catecholamine is released as well as the amount of Catecholamine that is released. The acute release of norepinephrine and epinephrine from PHEO increases heart rate, systemic vascular resistance, myocardial contractility, and reduces venous compliance. The excessive adrenergic stimulation by Catecholamine results in severe vasoconstriction and coronary vasospasm, myocardial ischemia, and subsequently damage, and necrosis. Chronically elevated Catecholamine levels lead to significant desensitization of cardiac β-adrenoceptors. The increased levels of the enzyme β-adrenoceptors kinase (βARK) in the heart seems to mediate these biochemical and physiological changes that are consistently correlated with attenuated responsiveness to Catecholamine stimulation. Through these mechanisms different types of cardiomyopathy (CMP) can be formed. This review discusses extensively the 3 types of cardiomyopathies that can be present in a PHEO patient. It also provides the clinical presentation and diagnostic and therapeutic algorithm in managing patients with CICMPP.