Delphinidin immobilized on silver nanoparticles for the simultaneous determination of ascorbic acid, noradrenalin, uric acid, and tryptophan

AbstractIn the present study, the fabrication of a new modified electrode for electrocatalytic oxidation of noradrenalin, based on the delphinidin immobilized on silver nanoparticles modified glassy carbon electrode. Cyclic voltammetry was used to investigate the redox properties of this modified electrode. The surface charge transfer rate constant (ks) and the charge transfer coefficient (α) for the electron transfer between the glassy carbon electrode and the immobilized delphinidin were calculated. The differential pulse voltammetry exhibited two linear dynamic ranges and a detection limit of 0.40μM for noradrenalin determination. Moreover, the present electrode could separate the oxidation peak potentials of ascorbic acid, noradrenalin, uric acid, and tryptophan in a mixture. The usefulness of this nanosensor was also investigated for the determination of ascorbic acid, noradrenalin, and uric acid in pharmaceutical and biological fluid samples with satisfactory results

Triacylglycerol synthesis in rat adipose tissue : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Biochemistry at Massey University

Adipose tissue consists of two types of cell; the adipocyte and the non-adipocyte {Rodbell, 1964). The adipocyte is unique amongst mammalian cell types in that one class of component {TG) comprises up to 80% of its weight. These TG's constitute the major energy storage material in higher animals. The importance of adipose tissue in mammalian metabolism lies in its ability to store free-fatty acids {FFA) as TG and to release them again according to physiological demands. It is therefore understandable that the pathways of synthesis and degradation should be under strict control. Apart from adipose tissue TG metabolism is especially active in the mammary gland during lactation and in the liver and intestinal mucosa cells during synthesis and secretion of serum lipoproteins. [From Chapter 1

The influence of motor activity on the development of cardiac arrhythmias during experimental emotional stress

Experimental emotional stress which can produce various disorders of cardiac rhythm: sinus tachycardia, atrial fibrillation, ventricular, extrasystoles and paroxysmal ventricular tachysystoles was studied. In these conditions the adrenalin content in the blood and myocardium is increased 3 to 4 times. It is found that moderate motor activity leads to a relative decrease of adrenalin in the myocardium and arrest of cardiac arrhythmias

Catecholamines of the adrenal medula and their morphological changes during adaptation to repeated immobilization stress

Changes of the adrenal medulla of rats were studied in the course of adaptation to repeated immobilization stress. An increase in the number of cells in the adrenal medulla was found in the adapted animals; this increase was confirmed by weight indices of the medulla and by cell counts per surface unit. Simultaneous karyometric measurements of the nuclei of adrenal medulla cells and an analysis of the catecholamine contents in the adrenals explain the increased activity of the adrenal medulla in the course of adaptation

Distinct forms of synaptic inhibition and neuromodulation regulate calretinin positive neuron excitability in the spinal cord dorsal horn

The dorsal horn (DH) of the spinal cord contains a heterogenous population of neurons that process incoming sensory signals before information ascends to the brain. We have recently characterized calretinin-expressing (CR+) neurons in the DH and shown that they can be divided into excitatory and inhibitory subpopulations. The excitatory population receives high-frequency excitatory synaptic input and expresses delayed firing action potential discharge, whereas the inhibitory population receives weak excitatory drive and exhibits tonic or initial bursting discharge. Here, we characterize inhibitory synaptic input and neuromodulation in the two CR+ populations, in order to determine how each is regulated. We show that excitatory CR+ neurons receive mixed inhibition from GABAergic and glycinergic sources, whereas inhibitory CR+ neurons receive inhibition, which is dominated by glycine. Noradrenaline and serotonin produced robust outward currents in excitatory CR+ neurons, predicting an inhibitory action on these neurons, but neither neuromodulator produced a response in CR+ inhibitory neurons. In contrast, enkephalin (along with selective mu and delta opioid receptor agonists) produced outward currents in inhibitory CR+ neurons, consistent with an inhibitory action but did not affect the excitatory CR+ population. Our findings show that the pharmacology of inhibitory inputs and neuromodulator actions on CR+ cells, along with their excitatory inputs can define these two subpopulations further, and this could be exploited to modulate discrete aspects of sensory processing selectively in the DH

Differential contractile response of critically ill patients to neuromuscular electrical stimulation

BACKGROUND: Neuromuscular electrical stimulation (NMES) has been investigated as a preventative measure for intensive care unit-acquired weakness. Trial results remain contradictory and therefore inconclusive. As it has been shown that NMES does not necessarily lead to a contractile response, our aim was to characterise the response of critically ill patients to NMES and investigate potential outcome benefits of an adequate contractile response. METHODS: This is a sub-analysis of a randomised controlled trial investigating early muscle activating measures together with protocol-based physiotherapy in patients with a SOFA score ≥ 9 within the first 72 h after admission. Included patients received protocol-based physiotherapy twice daily for 20 min and NMES once daily for 20 min, bilaterally on eight muscle groups. Electrical current was increased up to 70 mA or until a contraction was detected visually or on palpation. Muscle strength was measured by a blinded assessor at the first adequate awakening and ICU discharge. RESULTS: One thousand eight hundred twenty-four neuromuscular electrical stimulations in 21 patients starting on day 3.0 (2.0/6.0) after ICU admission were included in this sub-analysis. Contractile response decreased from 64.4% on day 1 to 25.0% on day 7 with a significantly lower response rate in the lower extremities and proximal muscle groups. The electrical current required to elicit a contraction did not change over time (day 1, 50.2 [31.3/58.8] mA; day 7, 45.3 [38.0/57.5] mA). The electrical current necessary for a contractile response was higher in the lower extremities. At the first awakening, patients presented with significant weakness (3.2 [2.5/3.8] MRC score). When dividing the cohort into responders and non-responders (> 50% vs. ≤ 50% contractile response), we observed a significantly higher SOFA score in non-responders. The electrical current necessary for a muscle contraction in responders was significantly lower (38.0 [32.8/42.9] vs. 54.7 [51.3/56.0] mA, p < 0.001). Muscle strength showed higher values in the upper extremities of responders at ICU discharge (4.4 [4.1/4.6] vs. 3.3 [2.8/3.8] MRC score, p = 0.036). CONCLUSION: Patients show a differential contractile response to NMES, which appears to be dependent on the severity of illness and also relevant for potential outcome benefits. TRIAL REGISTRATION: ISRCTN ISRCTN19392591 , registered 17 February 201

Influence of Amines in the Brain and Gastric Wall on Development of Stress Ulcers

With a view to examining the influence of amines in the brain and gastric wall on the development of stress ulcers, the authors loaded rats with the stress of cold restraint after administration of the inhibitory agents of produce and metabolism of amines, and the following findings were obtained. 1. Noradrenalin contents in the brain were significantly reduced after stress. The reduction relatively induced vagotonia and developed ulcers. Accordingly, noradrenalin in the brain associates with the development of stress ulcers. 2. Serotonin contents in the brain were increased significantly after stress, unlike the changes of the noradrenalin contents. But serotonin in the brain was not associated with the development of stress ulcers. 3. Histamine and serotonin contents in the gastric wall were reduced significantly after stress and both amines were associated with the development of stress ulcers. 4. Either of histamine or serotonin in the gastric wall was not be able to be the main cause on the development of stress ulcers, and their association was almost the same degree

Catecholamines and myocardial contractile function during hypodynamia and with an altered thyroid hormone balance

The dynamics of catecholamine content and myocardial contractile function during hypodynamia were studied in 109 white rats whose motor activity was severely restricted for up to 30 days. During the first five days myocardial catecholamine content, contractile function, and physical load tolerance decreased. Small doses of thyroidin counteracted this tendency. After 15 days, noradrenalin content and other indices approached normal levels and, after 30 days, were the same as control levels, although cardiac functional reserve was decreased. Thyroidin administration after 15 days had no noticeable effect. A detailed table shows changes in 17 indices of myocardial contractile function during hypodynamia

Experimental pharmacological research regarding the antidepressant effect of associating doxepin and selegiline in normal mice

The severity and complexity of depression can vary widely among individuals, thus making single drug therapy ineffective in some cases. Taking this fact into account and using a mouse model, we set on investigating the possibility of obtaining a synergism of action between a classical tricyclic antidepressant that inhibits noradrenalin and serotonin reuptake (doxepin), and a modern antidepressant that inhibits type-B monoamine oxidase (selegiline). We measured the antidepressant effect using the forced swimming test and the tail suspension test. We determined motor activity using the Activity Cage test. Our results have shown that the antidepressant effect intensifies significantly in the animals treated with both antidepressants simultaneously compared to those treated only with doxepin. Furthermore, we observed that selegiline decreases the sedative effect of doxepin in the Activity Cage test