Catecholamines

Distribution by Scientific Domains
Distribution within Medical Sciences

Terms modified by Catecholamines

  • catecholamine concentration
  • catecholamine level
  • catecholamine release
  • catecholamine secretion
  • catecholamine synthesis

  • Selected Abstracts


    Catecholamines, hypoxic defence and the neonatal brain

    DEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 2001
    Hugo Lagercrantz
    No abstract is available for this article. [source]


    Electrochemical Behavior of Catecholamines and Related Compounds at In Situ Surfactant Modified Carbon Paste Electrodes

    ELECTROANALYSIS, Issue 2-3 2007
    M.Carmen Blanco-López
    Abstract The voltammetric characteristics of catecholamines: epinephrine (E) and norepinephrine (NE) and related compounds: isoproterenol, metanephrine, L -dopa, methyldopa, vanillylmandelic acid (VMA), and homovanillic acid (HVA) at unmodified and in situ surfactant- modified carbon paste electrodes were comparatively evaluated. For the basic and amphoteric compounds the modification of the electrode surface with submicellar concentrations of anionic surfactants (sodium dodecylsulfate, sodium decylsulfate or sodium dodecylsulfonate) produce an important current enhancement in its oxidation and reduction peak current together with the improvement in the reversibility of the processes. These effects were explained in basis on electrostatic and hydrophobic interactions. On the other hand, the oxidation of acidic metabolites, HVA and VMA, was studied at electrodes modified in situ with cationic surfactants. Under certain conditions the surfactant could stabilise some of the electrochemical reaction intermediates, thus explaining the different voltammetric behaviour of HVA and VMA. [source]


    ISTA13-catecholamine toxicity and metabolism in the ciliated protozoan, Tetrahymena pyriformis

    ENVIRONMENTAL TOXICOLOGY, Issue 6 2009
    Asad Ud-Daula
    Abstract A high throughput culture methodology of unicellular eukaryote Tetrahymena pyriformis, strain GL were used for the determination of catecholamines toxicity and their metabolism. Catecholamines exhibited acute toxicity to Tetrahymena cells where dopamine and L -DOPA showed higher toxic potential of EC10 (0.39 and 0.63 mg/L, respectively) and EC20 (1.1 and 1.0 mg/L, respectively). All the testing catecholamines were highly degradable in the PPY-medium due to the oxidizing environment during incubation. They were also naturally synthesized and released by Tetrahymena cells into the culture medium and increasingly accumulated with time where as noradrenalin demonstrated significant results. Cells were exposed with physiological concentration (0.12 mg/L) and one higher concentration (8.0 mg/L) of catecholamines, resulting noradrenalin depletion and in vivo generation of a metabolite in response to dopamine with higher concentration treatment. This dopamine metabolite was relatively nonpolar compared with the catecholamines and was eluted later from the reverse phase C-18 column. © 2008 Wiley Periodicals, Inc. Environ Toxicol, 2009. [source]


    Increased Dopamine Is Associated With the cGMP and Homocysteine Pathway in Female Migraineurs

    HEADACHE, Issue 1 2010
    Hans-Jürgen Gruber PhD
    (Headache 2010;50:109-116) Background., The group of catecholamines, which include dopamine, adrenaline, and noradrenaline, are neurotransmitters which have been considered to play a role in the pathogenesis of migraine. However, the impact of catecholamines, especially dopamine on migraine as well as the exact mechanisms is not clear to date as previous studies have yielded in part conflicting results. Objective., This study aimed to produce a comprehensive examination of dopamine in migraineurs. Methods., Catecholamines and various parameters of the homocysteine, folate, and iron metabolism as well as cyclic guanosine monophosphate (cGMP) and inflammatory markers were determined in 135 subjects. Results., We found increased dopamine levels in the headache free period in female migraineurs but not in male patients. Increased dopamine is associated with a 3.30-fold higher risk for migraine in women. We found no significant effects of aura symptoms or menstrual cycle phases on dopamine levels. Dopamine is strongly correlated with cGMP and the homocysteine,folate pathway. Conclusion., We show here that female migraineurs exhibit increased dopamine levels in the headache free period which are associated with a higher risk for migraine. [source]


    Negative impact of systemic catecholamine administration on hepatic blood perfusion after porcine liver transplantation

    LIVER TRANSPLANTATION, Issue 2 2005
    Arianeb Mehrabi
    Catecholamines are often administered during and after liver transplantation (LTx) to support systemic perfusion and to increase organ oxygen supply. Some vasoactive agents can compromise visceral organ perfusion. We followed the hypothesis that the vasculature of transplanted livers presents with a higher sensitivity, which leads to an increased vulnerability for flow derangement after application of epinephrine (Epi) or norepinephrine (NorEpi). Hepatic macroperfusion and microperfusion during systemic Epi or NorEpi infusion were measured by Doppler flow and thermodiffusion probes in porcine native, denervated, and transplanted livers (n = 16 in each group). Epi or NorEpi were infused (n = 8 in each subgroup) in predefined dosages (low dose = 5 ,g/kg/minute and high dose = 10 ,g/kg/minute) over 240 minutes. Systemic cardiocirculatory parameters were monitored continuously. Hepatic perfusion data were compared between all groups at comparable time points and dosages. In all native, denervated, and transplanted liver groups, Epi and NorEpi induced an inconsistent rise of mean arterial pressure and heart rate shortly after onset of infusion in both dosages compared with baseline. No significant differences of cardiovascular parameters at comparable time points were observed. In native livers, Epi and NorEpi induced only temporary alterations of hepatic macrocirculation and microcirculation, which returned to baseline 2 hours after onset of infusion. No significant alterations of hepatic blood flow were detected after isolated surgical denervation of the liver. By contrast, transplanted livers showed a progressive decline of hepatic macrocirculation (33,75% reduction) and microcirculation (39,58% reduction) during catecholamine infusions in a dose-dependent fashion. Characteristics of liver blood flow impairment were comparable for both vasoactive agents. In conclusion, pronounced disturbances of hepatic macrocirculation and microcirculation were observed during systemic Epi and NorEpi infusion after LTx compared with native and denervated livers. Microcirculation disturbances after LTx might be explained by impairment of hepatic blood flow regulation caused by an increased sensitivity of hepatic vasculature after ischemia-reperfusion and by lengthening of vasopressor effects caused by reduced hepatocyte metabolism. Clinicians should be aware of this potentially hazardous effect. Therefore, application of catecholamines after clinical LTx should be indicated carefully. (Liver Transpl 2005;11:174,187.) [source]


    Attenuation of Histamine-Induced Endothelial Permeability Responses after Pacing-Induced Heart Failure: Role for Endogenous Catecholamines

    MICROCIRCULATION, Issue 5 2000
    DONNA L. DYESS
    ABSTRACT Objective: After congestive heart failure (CHF), lung endothelial permeability responses to a number of perturbations, including acute barotrauma, angiotensin II, and thapsigargin are blunted. Our hypothesis was that similar attenuation of permeability responses occurs in peripheral vascular beds after CHF. We compared peripheral microvascular permeability responses to the autacoid histamine in control dogs and in dogs paced to heart failure (245 bpm for ,36 days). Since catecholamines attenuate autacoid-induced increases in microvascular permeability in skin and muscle in normal animals, we also tested whether the known elevation in catecholamines in CHF was involved in any downregulation of permeability responses in this group. Methods: Control and paced dogs were anesthetized, intubated, and ventilated, and a hindpaw lymphatic cannulated. The reflection coefficient for total proteins (,) was measured at baseline and during one-hour, local intra-arterial histamine infusion. Results: In controls, , fell from 0.83 ± 0.02 to 0.73 ± 0.04 after histamine (p < 0.05), while in the paced group , was no different from that at baseline (0.77 ± 0.02). To test whether this difference was due to endogenous catecholamines, dogs were pretreated with propranolol (controls only) or the specific ,2 -antagonist ICI 118,551 prior to histamine infusion. After ,-blockade, histamine significantly reduced , in both control (0.83 ± 0.01 to 0.55 ± 0.05) and paced (0.83 ± 0.01 to 0.57 ± 0.07) groups (p < 0.05). Conclusion: We conclude that endogenous catecholamines, acting via ,2 -adrenergic receptors, attenuate the permeability response to histamine in pacing-induced heart failure. [source]


    The Impact of Catecholamines on Defibrillation Threshold in Patients with Implanted Cardioverter Defibrillators

    PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 11 2005
    JAMES S. KALUS
    Objectives: To determine the effect of physiologic catecholamine concentrations on the defibrillation threshold (DFT) in patients with implanted cardioverter defibrillators. Background: DFT is the minimum energy delivered by an implanted cardioverter defibrillator that successfully converts ventricular fibrillation. DFT testing is performed under conscious sedation. Since activities of daily living enhance sympathetic tone substantially over these nadir levels, it is important to explore the impact of catecholamines on DFT. Methods: In this double-blind study, we determined DFT by the step-down method. Patients (n = 50) were stratified by beta-blocker use and then randomized to a 7-minute infusion of epinephrine, norepinephrine, or placebo. After study infusion, DFT testing was repeated. Changes in DFT with different study medications were compared. Subgroup analyses of the effects of catecholamines on DFT, based on beta-blocker use, were also performed. Results: Norepinephrine reduced DFT from baseline measurements by 22.6% (P = 0.008). Neither epinephrine nor placebo impacted DFT (P = 0.999, P = 0.317, respectively). In the subgroup analyses, DFT was reduced with norepinephrine regardless of beta-blocker use, while epinephrine reduced DFT among those receiving beta-blockers. No change in DFT was observed in either of the placebo subgroups. Conclusions: Elevation of plasma norepinephrine concentrations reduces the DFT, while elevations in epinephrine had no effect. Norepinephrine seems to reduce DFT regardless of beta-blocker therapy but epinephrine's effects are beta-blocker dependent. [source]


    Synthesis and analysis of aminochromes by HPLC-photodiode array.

    BIOMEDICAL CHROMATOGRAPHY, Issue 1 2003
    Adrenochrome evaluation in rat blood
    Abstract The catecholamine oxidation process induces cardiotoxicity and neurotoxicity. Catecholamines can oxidize to aminochromes through autoxidation or by enzymatic or non-enzymatic catalysis. Although some toxic effects seem to be related to the formation of aminochromes there is still scarce information concerning the identification and evaluation of these compounds in in vivo models. In this study five catecholamines were oxidized to their respective aminochromes: adrenaline/adrenochrome; noradrenaline/noradrenochrome; dopa/dopachrome; dopamine/dopaminochrome; and isoproterenol/isoprenochrome. The evaluation of the catecholamines oxidation profile was performed by HPLC with photodiode array detection and using either enzymatic (tyrosinase) or non-enzymatic [Ag2O, CuSO4, NaIO4 and K3Fe(CN)6] catalytic systems. The NaIO4 was found to be the most efficient oxidant of catecholamines. An isocratic reverse-phase HPLC method was developed to analyse each pair of catecholamine,aminochrome. The analytical system was then applied to the detection of adrenochrome in rat blood at 490,nm. Thus, adrenochrome was administered i.p. to rats and its concentration in whole blood was monitored after 5, 15 and 25,min. Blood treatment for adrenochrome evaluation consists of an acidification for protein precipitation followed by a rapid neutralization. The results showed a rapid decrease of adrenochrome concentration in blood after its administration. The adrenochrome present in blood was characterized by UV and tandem mass spectrometry. Copyright © 2002 John Wiley & Sons, Ltd. [source]


    Acidosis and Catecholamine Evaluation Following Simulated Law Enforcement "Use of Force" Encounters

    ACADEMIC EMERGENCY MEDICINE, Issue 7 2010
    Jeffrey D. Ho MD
    ACADEMIC EMERGENCY MEDICINE 2010; 17:E60,E68 © 2010 by the Society for Academic Emergency Medicine Abstract Objectives:, Law enforcement authorities are often charged with controlling resisting suspects. These encounters sometimes result in the sudden and unexpected death of the suspect. Drug intoxication, excited delirium syndrome, or excessive uses of force are factors that are often blamed, but sometimes the mechanism of these deaths is not fully understood. It is possible that worsening acidosis or excessive catecholamine release play a part. The objective of this study was to determine the effect on markers of acidosis and catecholamines of various tasks intended to simulate common arrest-related situations. Methods:, Subjects were assigned to one of five task groups: 1) a 150-meter sprint and wall hurdle (simulated flight from arrest); 2) 45 seconds of striking a heavy bag (simulated physical resistance); 3) a 10-second TASER X26 electronic control device exposure; 4) a fleeing and resistance exercise involving a law enforcement dog (K-9); or 5) an oleoresin capsicum (OC) exposure to the face and neck. Baseline serum pH, lactate, potassium, troponin I, catecholamines, and creatine kinase (CK) were evaluated. Serum catecholamines, pH, lactate, and potassium were sampled immediately after the task and every 2 minutes for 10 minutes posttask. Vital signs were repeated immediately after the task. Serum CK and troponin I were evaluated again at 24 hours posttask. Results:, Sixty-six subjects were enrolled; four did not complete their assigned task. One subject lost the intravenous (IV) access after completing the task and did not have data collected, and one subject only received a 5-second TASER device exposure and was excluded from the study, leaving 12 subjects in each task group. The greatest changes in acidosis markers occurred in the sprint and heavy bag groups. Catecholamines increased the most in the heavy bag group and the sprint group and increased to a lesser degree in the TASER, OC, and K-9 groups. Only the sprint group showed an increase in CK at 24 hours. There were no elevations in troponin I in any group, nor any clinically important changes in potassium. Conclusions:, The simulations of physical resistance and fleeing on foot led to the greatest changes in markers of acidosis and catecholamines. These changes may be contributing or causal mechanisms in sudden custodial arrest-related deaths (ARDs). This initial work may have implications in guiding applications of force for law enforcement authorities (LEAs) when apprehending resisting subjects. [source]


    Amperometric Detection of Catecholamine Neurotransmitters Using Electrocatalytic Substrate Recycling at a Laccase Electrode

    ELECTROANALYSIS, Issue 2 2005
    Yvonne Ferry
    Abstract An enzyme electrode based on the coimmobilization of an osmium redox polymer and laccase on glassy carbon electrodes has been applied to ultra sensitive amperometric detection of the catecholamine neurotransmitters dopamine, epinephrine and norepinephrine, resulting in nanomolar detection limits, as low as 4,nM for dopamine. The sensitivity of the electrode is due to signal amplification via oxidation of the catecholamine by the immobilized laccase, which is regenerated by concomitant reduction of oxygen to water, coupled to the electrocatalytic re-reduction of the oxidized catecholamine by the osmium redox complex: electrocatalytic substrate recycling. In addition because the sensor can be operated in reductive mode at ,0.2,V (vs. Ag/AgCl), noise and interferences are diminished. Combined with its high sensitivity this enzyme electrode also exhibited excellent selectivity allowing the detection of catecholamines in the presence of ascorbic acid. However, differentiation between the current responses achieved for the three catecholamines is not possible. The effective mode of constant recycling, resulting in amplification of the current response, of the laccase enzyme electrode sensor combined with the inherent advantages of using electrochemical techniques holds great promise for the future of catecholamine detection and monitoring. [source]


    Circadian rhythm of aromatic l -amino acid decarboxylase in the rat suprachiasmatic nucleus: gene expression and decarboxylating activity in clock oscillating cells

    GENES TO CELLS, Issue 5 2002
    Yoshiki Ishida
    Background: Aromatic l -amino acid decarboxylase (AADC) is the enzyme responsible for the decarboxylation step in both the catecholamine and indoleamine synthetic pathways. In the brain, however, a group of AADC containing neurones is found outside the classical monoaminergic cell groups. Since such non-monoaminergic AADC is expressed abundantly in the suprachiasmatic nucleus (SCN), the mammalian circadian centre, we characterized the role of AADC in circadian oscillation. Results : AADC gene expression was observed in neurones of the dorsomedial subdivision of the SCN and its dorsal continuant in the anterior hypothalamic area. These AADC neurones could uptake exogenously applied L-DOPA and formed dopamine. AADC was co-expressed with vasopressin and the clock gene Per1 in the neurones of the SCN. Circadian gene expression of AADC was observed with a peak at subjective day and a trough at subjective night. The circadian rhythm of AADC enzyme activity in the SCN reflects the expression of the gene. Conclusions: Non-monoaminergic AADC in the SCN is expressed in clock oscillating cells, and the decarboxylating activity of master clock cells are under the control of the circadian rhythm. [source]


    Immunocytochemical evidence for biogenic amines and immunogold labeling of serotonergic synapses in tentacles of Aiptasia pallida (Cnidaria, Anthozoa)

    INVERTEBRATE BIOLOGY, Issue 4 2000
    Jane A. Westfall
    Abstract. Evidence for classical neurotransmitters in sea anemones remains controversial. We used high performance liquid chromatography with electrochemical detection (HPLC-EC) and electron microscopical imunocytochemistry to determine the presence of serotonin and precursor synthetic enzymes of other biogenic amines in tentacles of the sea anemone Aiptasia pallida. Using HPLC-EC we found dopamine and serotonin (5-hydroxytryptamine, 5-HT) in both tentacles and whole animal homogenates. Antibodies to tyrosine hydroxylase, dopamine ,-hydroxylase, phenylethanolamine N-methyltransferase, and 5-HT were used with the peroxidase-antiperoxidase method to reveal positive immunoreactivity to these substances in neurons of tentacles. Immunogold labeling of serial thin sections with the anti-5,HT antibody revealed reactive products in synaptic vesicles at interneuronal, neuromuscular, and neurospirocyte synapses. These results suggest that both catecholamine and indolamine neurotransmitters occur in sea anemones in addition to the neuropeptide Antho-RFamide, indicating the presence of multiple types of transmitter substances in an early nervous system. [source]


    Presynaptic regulation of dopaminergic neurotransmission

    JOURNAL OF NEUROCHEMISTRY, Issue 2 2003
    Yvonne Schmitz
    Abstract The development of electrochemical recordings with small carbon-fiber electrodes has significantly advanced the understanding of the regulation of catecholamine transmission in various brain areas. Recordings in vivo or in slice preparations monitor diffusion of catecholamine following stimulated synaptic release into the surrounding tissue. This synaptic ,overflow' is defined by the amount of release, by the activity of reuptake, and by the diffusion parameters in brain tissue. Such studies have elucidated the complex regulation of catecholamine release and uptake, and how psychostimulants and anti-psychotic drugs interfere with it. Moreover, recordings with carbon-fiber electrodes from cultured neurons have provided analysis of catecholamine release and its plasticity at the quantal level. [source]


    Effect of Urotensin II on PC12 Rat Pheochromocytoma Cells

    JOURNAL OF NEUROENDOCRINOLOGY, Issue 2 2010
    Y. Aita
    Urotensin II (U-II), initially identified as a cyclic peptide from fish urophysis, acts both as a strong vasoconstrictor and vasodilator in the vasculature via its receptor, G-protein coupled receptor 14. In addition, U-II and its receptor are co-expressed in the adrenal medulla, as well as in human pheochromocytomas, suggesting that this peptide may have some function in chromaffin cells. However, the precise role of U-II in these cells is unknown. In the present study, we initially demonstrate that U-II and its receptors mRNA are co-expressed in the rat pheochromocytoma cell line PC12. Moreover, U-II has not effect on tyrosine hydroxylase (TH), the rate-limiting enzyme involved in the biosynthesis of catecholamine, in terms of enzyme activity or at the mRNA level. However, U-II does induce an increase in the phosphorylation of TH specifically at Ser31 without affecting phosphorylation at the two other sites (Ser19 and Ser40). U-II also markedly activates extracellular signal-regulated kinases (ERKs) and p38, but not Jun N-terminal kinase. Blockade of the epidermal growth factor (EGF) receptor by AG1478 significantly reduces activation of ERK, suggesting that EGF receptor transactivation could act upstream of the ERK pathway in PC12 cells. Furthermore, U-II significantly increases dopamine secretion from PC12 cells. Finally, we show that U-II induced significant DNA synthesis in a ERKs and P38 mitogen-activated protein kinase-dependent manner. The results obtained indicate that U-II may exert its effects as a neuromodulator in chromaffin cells. [source]


    Lack of Association of Alcohol Dependence and Habitual Smoking With Catechol-O-methyltransferase

    ALCOHOLISM, Issue 11 2007
    Tatiana Foroud
    Objective:, To test whether variation in the gene encoding the enzyme catechol-O-methyltransferase (COMT), which catalyzes the breakdown of dopamine and other catecholamine neurotransmitters, is associated with the risk for alcohol dependence and habitual smoking. Methods:, Single nucleotide polymophisms (SNPs) were genotyped in a sample of 219 multiplex alcohol-dependent families of European American descent from the Collaborative Study on the Genetics of Alcoholism (COGA). Family-based tests of association were performed to evaluate the evidence of association between the 18 SNPs distributed throughout COMT, including the functional Val158Met polymorphism, and the phenotypes of alcohol dependence, early onset alcohol dependence, habitual smoking, and comorbid alcohol dependence and habitual smoking. Results:, No significant, consistent evidence of association was found with alcohol dependence, early onset alcohol dependence, habitual smoking or the comorbid phenotype. There was no evidence that the functional Val158Met polymorphism, previously reported to be associated with these phenotypes, was associated with any of them. Conclusion:, Despite the substantial size of this study, we did not find evidence to support an association between alcohol dependence or habitual smoking and variation in COMT. [source]


    The use of vasopressin for treating vasodilatory shock and cardiopulmonary arrest

    JOURNAL OF VETERINARY EMERGENCY AND CRITICAL CARE, Issue 2 2009
    DACVIM, Richard D. Scroggin Jr.
    Abstract Objective , To discuss 3 potential mechanisms for loss of peripheral vasomotor tone during vasodilatory shock; review vasopressin physiology; review the available animal experimental and human clinical studies of vasopressin in vasodilatory shock and cardiopulmonary arrest; and make recommendations based on review of the data for the use of vasopressin in vasodilatory shock and cardiopulmonary arrest. Data Sources , Human clinical studies, veterinary experimental studies, forum proceedings, book chapters, and American Heart Association guidelines. Human and Veterinary Data Synthesis , Septic shock is the most common form of vasodilatory shock. The exogenous administration of vasopressin in animal models of fluid-resuscitated septic and hemorrhagic shock significantly increases mean arterial pressure and improves survival. The effect of vasopressin on return to spontaneous circulation, initial cardiac rhythm, and survival compared with epinephrine is mixed. Improved survival in human patients with ventricular fibrillation, pulseless ventricular tachycardia, and nonspecific cardiopulmonary arrest has been observed in 4 small studies of vasopressin versus epinephrine. Three large studies, though, did not find a significant difference between vasopressin and epinephrine in patients with cardiopulmonary arrest regardless of initial cardiac rhythm. No veterinary clinical trials have been performed using vasopressin in cardiopulmonary arrest. Conclusion , Vasopressin (0.01,0.04 U/min, IV) should be considered in small animal veterinary patients with vasodilatory shock that is unresponsive to fluid resuscitation and catecholamine (dobutamine, dopamine, and norepinephrine) administration. Vasopressin (0.2,0.8 U/kg, IV once) administration during cardiopulmonary resuscitation in small animal veterinary patients with pulseless electrical activity or ventricular asystole may be beneficial for myocardial and cerebral blood flow. [source]


    Cardiac failure and multiple organ dysfunction syndrome in a patient with endocrine adenomatosis

    ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 9 2002
    M. W. Dünser
    In this case report, we present the successful therapy of severe cardiac failure in pituitary adrenal insufficiency. A previously healthy 56-year-old-man in pituitary coma due to an atypical variant of multiple endocrine adenomatosis (pituitary adenoma and pheochromocytoma) suffered from cardiac failure resistant to catecholamine and standard hydrocortisone therapy. After two bolus injections of dexamethasone (2 × 24 mg) mean arterial pressure and cardiac function dramatically improved, probably due to restoration of permissive effects on catecholamine action and reversal of pathophysiological mechanisms of cardiac failure. We conclude that in patients with severe cardiovascular failure in pituitary coma the administration of potent glucocorticoids may be more effective in reversing cardiovascular failure than standard dosages of hydrocortisone. [source]


    Composite paraganglioma,ganglioneuroma of the urinary bladder

    PATHOLOGY INTERNATIONAL, Issue 9 2005
    Hiroyuki Usuda
    Presented herein is the case of a 73-year-old man, complaining of dysuria, who had a composite paraganglioma,ganglioneuroma of the urinary bladder (CPGUB). At cystoscopy a submucosal tumor was found in the urinary bladder and resected after transurethral biopsy. The levels of serum catecholamine and 24 h urinary excretion of catecholamine and vanillylmandelic acid were elevated. Grossly, the resected tumor, measuring 4 × 3 × 2.5 cm, had a brownish cut surface with no necrosis and hemorrhage. Histologically, the tumor had alternating cellular and fibrous areas. The cellular areas consisted of polygonal cells, arranged in well-defined nests (Zellballen) and positive for Grimelius staining, with abundant amphophilic to acidophilic cytoplasm, occasionally containing eosinophilic hyaline globules and brown pigments. Although the nuclei of several polygonal cells were bizarre, mitoses and vascular invasion were not found. Fibrous areas consisted of spindle cells, resembling Schwann cell, admixed with ganglionic cells. To the authors' knowledge, only four cases of CPGUB have been reported in the English-language literature. Detailed reported cases and the present case showed no malignant features, such as extra-bladder infiltration and metastasis, and no recurrence in the short length of follow up. Accumulation of long-term follow-up cases may provide valuable prognostic information on this composite tumor. [source]


    Vitamin B2 -sensitized Photo-oxidation of Dopamine

    PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 5 2008
    Walter A. Massad
    Kinetics and mechanism of the photo-oxidation of the natural catecholamine-type neurotransmitter dopamine (DA) has been studied in aqueous solution, under aerobic conditions, in the presence of riboflavin (Rf, vitamin B2) as a photosensitizer. Results indicate the formation of a weak dark complex Rf,DA, with a mean apparent association constant Kass = 30 m,1, only detectable at DA concentrations much higher than those employed in photochemical experiments. An intricate mechanism of competitive reactions operates upon photoirradiation. DA quenches excited singlet and triplet states of Rf, with rate constants of 4.2 × 109 and 2.2 × 109 m,1 s,1, respectively. With the catecholamine in a concentration similar to that of dissolved molecular oxygen in air-saturated water, DA and oxygen competitively quench the triplet excited state of Rf, generating superoxide radical anion (O2,,) and singlet molecular oxygen (O2(1,g)) by processes initiated by electron and energy-transfer mechanisms, respectively. Rate constants values of 1.9 × 108 and 6.6 × 106 m,1 s,1 have been obtained for the overall and reactive (chemical) interaction of DA with O2(1,g). The presence of superoxide dismutase increases both the observed rates of aerobic DA photo-oxidation and oxygen uptake, due to its known catalytic scavenging of O2,,, a species that could revert the overall photo-oxidation effect, according to the proposed reaction mechanism. As in most of the catecholamine oxidative processes described in the literature, aminochrome is the DA oxidation product upon visible light irradiation in the presence of Rf. It is generated with a quantum yield of 0.05. [source]


    Synthesis and analysis of aminochromes by HPLC-photodiode array.

    BIOMEDICAL CHROMATOGRAPHY, Issue 1 2003
    Adrenochrome evaluation in rat blood
    Abstract The catecholamine oxidation process induces cardiotoxicity and neurotoxicity. Catecholamines can oxidize to aminochromes through autoxidation or by enzymatic or non-enzymatic catalysis. Although some toxic effects seem to be related to the formation of aminochromes there is still scarce information concerning the identification and evaluation of these compounds in in vivo models. In this study five catecholamines were oxidized to their respective aminochromes: adrenaline/adrenochrome; noradrenaline/noradrenochrome; dopa/dopachrome; dopamine/dopaminochrome; and isoproterenol/isoprenochrome. The evaluation of the catecholamines oxidation profile was performed by HPLC with photodiode array detection and using either enzymatic (tyrosinase) or non-enzymatic [Ag2O, CuSO4, NaIO4 and K3Fe(CN)6] catalytic systems. The NaIO4 was found to be the most efficient oxidant of catecholamines. An isocratic reverse-phase HPLC method was developed to analyse each pair of catecholamine,aminochrome. The analytical system was then applied to the detection of adrenochrome in rat blood at 490,nm. Thus, adrenochrome was administered i.p. to rats and its concentration in whole blood was monitored after 5, 15 and 25,min. Blood treatment for adrenochrome evaluation consists of an acidification for protein precipitation followed by a rapid neutralization. The results showed a rapid decrease of adrenochrome concentration in blood after its administration. The adrenochrome present in blood was characterized by UV and tandem mass spectrometry. Copyright © 2002 John Wiley & Sons, Ltd. [source]


    Relaxant effects of , -adrenergic agonists on porcine and human detrusor muscle

    ACTA PHYSIOLOGICA, Issue 2 2005
    J. K. Badawi
    Abstract Aim:, Relaxant effects of different , -adrenoceptor agonists on porcine and human detrusor were examined. Thus, the , -adrenoceptor subtype mainly responsible for relaxation in the detrusor muscle of pigs was characterized. Additionally, different effects of several , -agonists in both species were shown. Methods:, Experiments were performed on muscle strips of porcine and human detrusor suspended in a tissue bath. The relaxant effects of the non-selective , -agonist isoprenaline, the selective ,2-agonists procaterol, salbutamol and the selective ,3-agonists BRL 37344, CL 316 243 and CGP 12177 on potassium-induced contraction were investigated. The inhibitory effect of different substances on the maximum contraction and the rank order of potency for endogenous catecholamines was determined in pigs. Furthermore, concentration-relaxation curves were performed for pigs and humans. Results:,Pigs: In the pre-treatment experiments isoprenaline and procaterol showed similar effects. The concentration,response experiments showed that the maximum relaxation induced by procaterol and salbutamol was more than 90%, not significantly different from isoprenaline, whereas the maximum relaxations of CL 316 243, BRL 37344 and CGP 12177 amounted to 68, 70 or 30%, respectively. Rank order of potencies was isoprenaline , adrenaline > noradrenaline. Humans: Isoprenaline, procaterol, salbutamol and CL 316 243 showed a maximum relaxation of 80, 41, 24 and 35% and pD2 values of 6.24, 5.65, 5.48 and 5.55, respectively. Conclusion:,,2-receptors play a main functional role in mediating relaxation of porcine detrusor. Selective ,2- and ,3-agonists similarly relax the human detrusor. Effects were smaller compared with the pig. [source]


    Fate of fatty acids at rest and during exercise: regulatory mechanisms

    ACTA PHYSIOLOGICA, Issue 4 2003
    M. D. Jensen
    Abstract Fatty acids are a major fuel source for humans both at rest and during exercise. Plasma free fatty acids (FFA), although present only in micromolar concentrations, are the major circulating lipid fuel. FFA availability can increase two- to four-fold with moderate intensity exercise. Other potential sources of fatty acids include circulating very low-density lipoprotein (VLDL) triglycerides (TGs) (,1/5 the fuel availability of FFA) and intramyocellular TGs (,2 mmol kg,1 muscle). At rest ,40% of systemic FFA uptake occurs in the splanchnic bed and uptake in legs is ,15,20%. During leg exercise the uptake of FFA in leg tissue increases to 30,60% of systemic uptake and splanchnic uptake decreases to 15%. The fate of VLDL TG fatty acids has not been adequately studied. Intramyocellular TG hydrolysis increases during exercise, but the factors that regulate this response are not clear. The fact that contraction of isolated muscles can stimulate the hydrolysis and oxidation of intramyocellular TGs (in the absence of hormonal or neural input) suggests an intracellular regulation of this process. Additional regulation from changes in catecholamines and insulin may also occur. During moderate intensity exercise circulating FFA and intramyocellular TG provide roughly equal portions of fatty acids for oxidation. In addition to endurance training, dietary factors have been shown to modulate the fatty acid oxidation response to exercise. Much remains to be learned about fatty acid trafficking during exercise. What role do VLDL TG play? How is the oxidation of intramyocellular TGs regulated? Techniques to address these questions in humans are only now becoming available. [source]


    Ontogeny of tyrosine hydroxylase mRNA expression in mid- and forebrain: Neuromeric pattern and novel positive regions

    DEVELOPMENTAL DYNAMICS, Issue 3 2005
    Faustino Marín
    Abstract Tyrosine hydroxylase (TH) is the rate-limiting enzyme in the synthesis of catecholamines and, thus, critical in determining the catecholaminergic phenotype. In this study, we have examined the expression of TH mRNA by in situ hybridization in the embryonic mouse forebrain and midbrain and have mapped its localization according to the neuromeric pattern. We find that early in embryonic development, 10 to 12 days post coitum (dpc), TH mRNA is expressed in ample continuous regions of the neuroepithelium, extending across several neuromeres. However, from 12.5 dpc onward, the expression becomes restricted to discrete regions, which correspond to the dopaminergic nuclei (A8 to A15). In addition to these nuclei previously described, TH mRNA is also observed in regions that do not express this enzyme according to immunohistochemical studies. This difference in relation to protein expression pattern is consequent with the known posttranscriptional regulation of TH expression. The most representative example of a novel positive region is the conspicuous mRNA expression in both medial and lateral ganglionic eminences. This result agrees with reports describing the capacity of striatal stem cells (that is, located at the lateral ganglionic eminence) to become dopaminergic in vitro. Other regions include the isthmic mantle layer and the early floor plate of the midbrain,caudal forebrain. On the whole, the expression map we have obtained opens new perspectives for evolutionary/comparative studies, as well as for therapeutic approaches looking for potentially dopaminergic cells. Developmental Dynamics 234:709,717, 2005. © 2005 Wiley-Liss, Inc. [source]


    Probable trigeminal autonomic cephalgia in a 3-month-old male infant

    DEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 4 2010
    IRENE VAZ
    To my knowledge trigeminal autonomic cephalgias (TACs) have not previously been reported in infancy. The diagnosis is dependent on an accurate history, including parents noting any physical signs at the time of the episode. Obtaining a clear history can be challenging when such symptoms occur in preverbal children. Similarly, physical signs, being transient, may have resolved by the time the parents take the child to a doctor. In addition, the investigations may also be normal. In such circumstances, taking a photograph during an episode can confirm the diagnosis. I describe a case of probable trigeminal autonomic cephalgia starting in a 3-month-old male infant who presented with screaming episodes associated with characteristic changes seen on his face. Investigations, including cranial magnetic resonance imaging, electroencephalography, and urinary catecholamines, were normal. The diagnosis was confirmed from a photograph taken by the parents at the time of the attack. As the condition is very rare in young children, there is little information available in the literature on using treatment for prophylaxis or for aborting acute episodes in this age group. [source]


    Aromatic l -amino acid decarboxylase deficiency associated with epilepsy mimicking non-epileptic involuntary movements

    DEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 11 2008
    Susumu Ito MD
    Aromatic l -amino acid decarboxylase (AADC) deficiency is a rare inborn error of neurotransmitter biosynthesis that leads to a combined deficiency of catecholamines and serotonin and is characterized by global developmental delay, involuntary movements, and autonomic dysfunction. We report the case of an 11-year-old male patient with AADC deficiency who also had epileptic spasms and generalized tonic seizures with asymmetrical features, in addition to frequent involuntary non-epileptic movements. The clinical manifestation of the epileptic attacks apparently resembled that of non-epileptic attacks. It was difficult to differentiate between both attacks without the help of an ictal electroencephalographic study. The epileptic attacks were finally controlled by appropriate antiepileptic drugs. Because an association with epileptic seizures is uncommon in AADC deficiency, some cases may have been regarded as involuntary non-epileptic movements. This indicates that the differentiation of epileptic attacks from non-epileptic ones is indispensable for the adequate treatment of patients with AADC deficiency. [source]


    Is insulin resistance caused by defects in insulin's target cells or by a stressed mind?

    DIABETES/METABOLISM: RESEARCH AND REVIEWS, Issue 6 2005
    Jonas Burén
    Abstract The importance of understanding insulin action is emphasized by the increasing prevalence of insulin resistance in various populations and by the fact that it plays an important pathophysiological role in many common disorders, for example, diabetes, obesity, hypertension and dyslipidemia. The primary factors responsible for the development of insulin resistance are so far unknown, although both genetic and environmental factors are involved. The genetic defects responsible for the common forms of insulin resistance, for example, in type 2 diabetes, are largely unidentified. Some studies from our group as well as by other investigators suggest that cellular insulin resistance is reversible and that it may be secondary to factors in the in vivo environment. These may include insulin-antagonistic action of hormones like catecholamines, glucocorticoids, sex steroids and adipokines as well as dysregulation of autonomic nervous activity and they could contribute to the early development of insulin resistance. Some of these factors can directly impair glucose uptake capacity and this might be due to alterations in key proteins involved in insulin's intracellular signaling pathways. This article briefly summarizes proposed mechanisms behind cellular and whole-body insulin resistance. In particular, we question the role of intrinsic defects in insulin's target cells as primary mechanisms in the development of insulin resistance in type 2 diabetes and we suggest that metabolic and neurohormonal factors instead are the main culprits. Copyright © 2005 John Wiley & Sons, Ltd. [source]


    Characteristic patterns of circadian variation in plasma catecholamine levels, blood pressure and heart rate variability in Type 2 diabetic patients

    DIABETIC MEDICINE, Issue 5 2002
    K. Kondo
    Abstract Aims To investigate whether Type 2 diabetic patients exhibit characteristic patterns of circadian variation in plasma levels of catecholamines, blood pressure (BP) and heart rate variability (HRV). Methods Ten Type 2 diabetic and eight control in-patients were studied. Blood for catecholamine measurement was collected every 4 h, and non-invasive ambulatory BP and heart rate were monitored throughout the day. HRV was determined using frequency domain methods. Results Diabetic patients showed a different pattern of circadian variation in BP and HRV from that of controls, the diurnal-nocturnal differences (D-N) being significantly smaller. The mean 24-h HRV levels were reduced in diabetic subjects. The mean 24-h plasma noradrenaline level of 1.36 ± 0.12 nmol/l in diabetic patients was significantly lower than the 2.03 ± 0.20 nmol/l in controls (P < 0.01). In contrast, no significant difference in adrenaline levels was observed. The mean 24-h plasma noradrenaline level demonstrated a significant positive correlation with D-N in systolic BP (r = 0.49, P = 0.0153). Conclusions The present study demonstrated distinctive patterns of circadian variation in plasma noradrenaline level, BP and HRV in Type 2 diabetic patients, associated with an abnormal circadian pattern of sympathovagal modulation. [source]


    Electrochemical Behavior of Catecholamines and Related Compounds at In Situ Surfactant Modified Carbon Paste Electrodes

    ELECTROANALYSIS, Issue 2-3 2007
    M.Carmen Blanco-López
    Abstract The voltammetric characteristics of catecholamines: epinephrine (E) and norepinephrine (NE) and related compounds: isoproterenol, metanephrine, L -dopa, methyldopa, vanillylmandelic acid (VMA), and homovanillic acid (HVA) at unmodified and in situ surfactant- modified carbon paste electrodes were comparatively evaluated. For the basic and amphoteric compounds the modification of the electrode surface with submicellar concentrations of anionic surfactants (sodium dodecylsulfate, sodium decylsulfate or sodium dodecylsulfonate) produce an important current enhancement in its oxidation and reduction peak current together with the improvement in the reversibility of the processes. These effects were explained in basis on electrostatic and hydrophobic interactions. On the other hand, the oxidation of acidic metabolites, HVA and VMA, was studied at electrodes modified in situ with cationic surfactants. Under certain conditions the surfactant could stabilise some of the electrochemical reaction intermediates, thus explaining the different voltammetric behaviour of HVA and VMA. [source]


    Amperometric Detection of Catecholamine Neurotransmitters Using Electrocatalytic Substrate Recycling at a Laccase Electrode

    ELECTROANALYSIS, Issue 2 2005
    Yvonne Ferry
    Abstract An enzyme electrode based on the coimmobilization of an osmium redox polymer and laccase on glassy carbon electrodes has been applied to ultra sensitive amperometric detection of the catecholamine neurotransmitters dopamine, epinephrine and norepinephrine, resulting in nanomolar detection limits, as low as 4,nM for dopamine. The sensitivity of the electrode is due to signal amplification via oxidation of the catecholamine by the immobilized laccase, which is regenerated by concomitant reduction of oxygen to water, coupled to the electrocatalytic re-reduction of the oxidized catecholamine by the osmium redox complex: electrocatalytic substrate recycling. In addition because the sensor can be operated in reductive mode at ,0.2,V (vs. Ag/AgCl), noise and interferences are diminished. Combined with its high sensitivity this enzyme electrode also exhibited excellent selectivity allowing the detection of catecholamines in the presence of ascorbic acid. However, differentiation between the current responses achieved for the three catecholamines is not possible. The effective mode of constant recycling, resulting in amplification of the current response, of the laccase enzyme electrode sensor combined with the inherent advantages of using electrochemical techniques holds great promise for the future of catecholamine detection and monitoring. [source]


    Dual-asymmetry electrokinetic flow focusing for pre-concentration and analysis of catecholamines in CE electrochemical nanochannels

    ELECTROPHORESIS, Issue 14 2009
    Ren-Guei Wu
    Abstract In this research, a technique incorporating dual-asymmetry electrokinetic flow (DAEKF) was applied to a nanoCE electrochemical device for the pre-concentration and detection of catecholamines. The DAEKF was constructed by first generating a ,-potential difference between the top and bottom walls, which had been pre-treated with O2 and H2O surface plasma, respectively, yielding a 2-D gradient shear flow across the channel depth. The shear flow was then exposed to a varying ,-potential along the downstream direction by control of the field-effect in order to cause downward rotational flow in the channel. By this mechanism, almost all of the samples were effectively brought down to the electrode surface for analysis. Simulations were carried out to reveal the mechanism of concentration caused by the DAEKF, and the results reasonably describe our experiment findings. This DAEKF technique was applied to a glass/glass CE electrochemical nanochip for the analysis of catecholamines. The optimum detection limit was determined to be 1.25 and 3.3,nM of dopamine and catechol, respectively. A detection limit at the zeptomole level for dopamine can be obtained in this device, which is close to the level released by a single neuron cell in vitro. [source]