Diss. (sammanfattning) Stockholm : Karol. inst. / Härtill 6 uppsatser.

Wong Kwok Kui Wister. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1992. / Includes bibliographical references (leaves 220-236). / ABSTRACT --- p.1 / OBJECTIVES FOR PROJECT --- p.4 / ABBREVIATIONS --- p.6 / Chapter CHAPTER 1 --- INTRODUCTORY LITERATURE REVIEWS / Chapter 1.1 --- Noradrenaline and adrenaline / Chapter 1.1.1 --- History --- p.8 / Chapter 1.2 --- The adrenal medulla / Chapter 1.2.1 --- The anatomy and microcirculation of the adrenal medulla --- p.10 / Chapter 1.2.2 --- Neuro-endocrine control of adrenal medullary secretion --- p.12 / Chapter 1.3 --- Dopamine / Chapter 1.3.1 --- Introduction --- p.14 / Chapter 1.3.2 --- Levels of DA in plasma and urine --- p.14 / Chapter 1.3.3 --- Origins of DA in the urine --- p.15 / Chapter 1.3.4 --- Control of renal DA production --- p.16 / Chapter 1.3.5 --- The actions of DA in the body --- p.17 / Chapter 1.3.6 --- The DA hypothesis --- p.17 / Chapter 1.3.7 --- Urinary NA and AD --- p.18 / Chapter 1.4 --- ACE inhibitors / Chapter 1.4.1 --- Brief review of the pharmacology of ACE inhibitors --- p.19 / Chapter 1.5 --- Catecholamine assays / Chapter 1.5.1 --- Introduction --- p.21 / Chapter 1.5.2 --- Chemistry --- p.22 / Chapter 1.5.3 --- Bioassay --- p.23 / Chapter 1.5.4 --- Colorimetry --- p.25 / Chapter 1.5.5 --- Fluorometry --- p.25 / Chapter 1.5.6 --- Radiochemical techniques --- p.27 / Chapter 1.5.7 --- Radioimmunoassay --- p.29 / Chapter 1.5.8 --- Chromatography --- p.30 / Chapter CHAPTER 2 --- METHODS - DEVELOPMENT OF A CATECHOLAMINE ASSAY & STABILITY STUDIES ON CATECHOLAMINES / Chapter 2.1 --- High performance liquid chromatography and electrochemical detection of catecholamines / Chapter 2.1.1 --- Introduction --- p.38 / Chapter 2.1.2 --- Basic equipment --- p.39 / Chapter 2.1.3 --- Stock aqueous CAT standards --- p.40 / Chapter 2.1.4 --- Mobile phase of HPLC-ECD --- p.40 / Chapter 2.1.5 --- Determination of mobile phase composition and flow rate --- p.41 / Chapter 2.1.6 --- Electrochemical detection --- p.43 / Chapter 2.1.7 --- Linearity and lowest detection limit of HPLC-ECD system --- p.49 / Chapter 2.1.8 --- Maintenance of HPLC-ECD system --- p.54 / Chapter 2.1.9 --- Discussion --- p.56 / Chapter 2.2 --- Sample pre-treatment & stability studies - Human urine / Chapter 2.2.1 --- Pre-treatment --- p.58 / Chapter 2.2.2 --- Analytical performance of the assay --- p.63 / Chapter 2.2.3 --- Stability studies --- p.85 / Chapter 2.2.4 --- Discussion --- p.101 / Chapter 2.2.5 --- Conclusions --- p.108 / Chapter 2.3 --- Sample pre-treatment & stability studies - Rat urine / Chapter 2.3.1 --- Pre-treatment --- p.111 / Chapter 2.3.2 --- Analytical performance of the assay --- p.111 / Chapter 2.3.3 --- Stability studies --- p.119 / Chapter 2.3.4 --- Discussion --- p.131 / Chapter 2.3.5 --- Conclusions --- p.133 / Chapter CHAPTER 3 --- "URINARY CREATININE, SODIUM AND POTASSIUM MEASUREMENTS" / Chapter 3.1 --- Introduction --- p.135 / Chapter 3.2 --- Method / Chapter 3.2.1 --- Urinary creatinine measurement --- p.135 / Chapter 3.2.2 --- Urinary sodium and potassium measurement --- p.136 / Chapter 3.3 --- Results / Chapter 3.3.1 --- Urinary creatinine measurement --- p.136 / Chapter 3.3.2 --- Urinary sodium and potassium measurement --- p.136 / Chapter 3.4 --- Discussion / Chapter 3.4.1 --- Urinary creatinine measurement --- p.136 / Chapter 3.4.2 --- Urinary sodium and potassium measurement --- p.137 / Chapter 3.5 --- Statistics --- p.138 / Chapter 3.6 --- Chemicals --- p.139 / Chapter CHAPTER 4 --- STUDIES ON URINARY EXCRETION OF CATECHOLAMINES IN MAN / Chapter 4.1 --- Population study on the relationships between dietary salt intake and urinary catecholamine output / Chapter 4.1.1 --- Introduction --- p.141 / Chapter 4.1.2 --- Method --- p.142 / Chapter 4.1.3 --- Results --- p.143 / Chapter 4.1.4 --- Discussion --- p.148 / Chapter 4.1.5 --- Conclusions --- p.149 / Chapter 4.2 --- The effect of oral salt loading on urinary catecholamine output / Chapter 4.2.1 --- Introduction --- p.149 / Chapter 4.2.2 --- Methods --- p.150 / Chapter 4.2.3 --- Results --- p.152 / Chapter 4.2.4 --- Discussion --- p.159 / Chapter 4.2.5 --- Conclusions --- p.161 / Chapter 4.3 --- The effects of perindopril on urinary catecholamine outputs / Chapter 4.3.1 --- Introduction --- p.162 / Chapter 4.3.2 --- Methods --- p.165 / Chapter 4.3.3 --- Results --- p.166 / Chapter 4.3.4 --- Discussion --- p.189 / Chapter 4.3.5 --- Conclusions --- p.190 / Chapter CHAPTER 5 --- STUDY ON URINARY EXCRETION OF CATECHOLAMINES AFTER ORAL ADMINISTRATION OF CAPTOPRIL TO RATS / Chapter 5.1 --- Introduction --- p.192 / Chapter 5.2 --- Methods --- p.192 / Chapter 5.3 --- Results --- p.193 / Chapter 5.4 --- Discussion --- p.210 / Chapter 5.5 --- Conclusions --- p.212 / Chapter CHAPTER 6 --- CONCLUSIONS --- p.214 / Chapter CHAPTER 7 --- FUTURE PROSPECTS --- p.216 / PUBLICATIONS TO DATE --- p.218 / ACKNOWLEDGEMENTS --- p.219 / REFERENCES --- p.220

This thesis describes metabolic changes occurring in chromaffin cells when secreting catecholamine (principally adrenaline), and the factors involved in maintaining the rate of secretion. In perfused pig adrenal glands, <sup>31</sup/>p nuclear magnetic resonance showed that nucleotide stored with catecholamine in the secretory vesicles (chromaffin granules) of the chromaffin cell was distinguishable from cytoplasmic nucleotide. Intragranular pH was 5.52 ± 0.15 (± SD, n=8) in ischaemic glands and rose (+ 0.22 ± 0.16 (± SD, n=6)) on recovery of cytoplasmic ATP during perfusion. This suggests that catecholamine accumulation by the granules is not driven by an ATP-generated pH gradient in intact tissue, as cytoplasmic ATP did not reduce intragranular pH. Perfused cortex-free ox adrenal medulla consumed 0.51 ± 0.19 (± SD, n=8) μmole 0₂/min/g wet weight after 210-230 minutes of perfusion, and this rose 30% during 4 minute O.lmM acetylcholine stimulations. This enhancement correlated with secretion but depended on the mode of stimulation, indicating that ATP consumption in secretion itself was an inadequate explanation. The proton-translocating Mg-ATPase of the chromaffin granule may hydrolyse ATP at its uncoupled rate on entering the plasma membrane during secretion by exocytosis. 1.4 ± 0.9 (± SD, n=12) moles of catecholamine were secreted per mole of enhanced oxygen consumption over 16 minutes. From this ratio, the oxygen consumption enhancement is shown to be much larger than that predicted from uncoupled proton pumping. Ouabain-sensitive oxygen consumption rose from < 6% to 18 ± 8% (± SD, n=4) during prolonged acetylcholine stimulation in the absence of calcium, suggesting that Na,K-ATPase was not responsible for all of the oxygen consumption enhancement. On continuous stimulation, secretion showed a biphasic decline in both pig and ox. A decline was also observed on intermittent stimulation. Cell death, potential-sensitive calcium gating and acetylcholine receptor desensitisation were only minor contributors. Little recovery occurred on resting the tissue for 2-3 hours between stimulations. The results are explained in terms of depletion of a pool of chromaffin granules adjacent to the plasma membrane.

The present study has established that physiological concentrations of estradiol can modulate stress-induced increases in plasma epinephrine (EPI). In anesthetized female rats, insulin-induced hypoglycemia (0.25 U/kg) increased plasma EPI concentration to a significantly greater extent in 14-day ovariectomized (OVEX) rats compared to sham-operated controls. In 17-estradiol (E2)-replaced OVEX rats, the hypoglycemia-induced rise in plasma EPI was significantly reduced compared to OVEX rats. This suppression was due to both decreased adrenal medullary output and increased clearance of EPI. Adrenal venous EPI concentration was significantly reduced in OVEX+E2 rats, suggesting that EPI secretion from the adrenalmedulla was decreased by E2 replacement. The underlying mechanism(s) of this apparent E2-mediated reduction in secretion could not be established since 1) the expression levels of the biosynthetic enzymes tyrosine hydroxylase and phenylethanolamine N-methyltransferase were not affected in OVEX+E2 rats, suggesting that EPI biosynthesis is similar in these and OVEX rats; and 2) agonist-induced increases in intracellular CaP2+P were identical in isolated adrenal medullary chromaffin cells exposed to E2 (10 nM) or vehicle for 48 hr, suggesting that stimulus secretion coupling is unaffected by E2 treatment. In contrast, plasma clearance of EPI was significantly increased in OVEX+E2 rats. Although 48 hr exposure to E2 had no effect on intracellular signaling in chromaffin cells, acute (3 min) exposure to micromolar concentrations of E2 dose-dependently and reversibly inhibited agonist-induced CaP 2+Ptransients. Consistent with this observation, acute (30 min) infusions of E2 also significantly reduced the insulin-induced increase in plasma EPI in OVEX rats. These data demonstrate that physiological levels of circulating E2 can modulate hypoglycemia-induced increases in plasma EPI. This effect appears to be mediated by the steroids influence on adrenal medullary EPI output and plasma EPI clearance; however the mechanism(s) underlying these E2-mediated modulations remain undetermined. This study has also established that acute exposure to supra-physiological levels of E2 can suppress hypoglycemia-induced increases in plasma EPI, due at least in part to inhibition of stimulus-secretion coupling.

Thesis (doctoral)--University of Tampere, 1984. / Includes previously published articles. Includes bibliographical references (p. 47-56 (1st group)).

Thesis (Ph.D.)--Georgetown University, 2009. / Includes bibliographical references.

The adrenal medulla is the inner part of adrenal glands located above each kidney, that produces catecholamines. Neuroblastoma and pheochromocytoma are the most prevalent malignancies of the adrenal medulla. Quantitative diagnosis of urinary catecholamines using HPLC-coupled Mass detectors is the current method for the diagnosis of neuroblastoma and pheochromocytoma. There are two major problems with this approach, (i) Because the catecholamines concentrations have short half-life (10-100 s), a series of urine tests must be performed throughout 24hr, detecting each catecholamine separately, is inconvenient and time-consuming; (ii) mass detectors are expensive, bulky, and require highly skilled personal. Vanillylmandelic (VMA), and homavanillic acid (HVA) are the by-products of catecholamines and are emerging alternative biomarker for catecholamines due to their high stability. Here, we developed a rapid, sensitive, miniaturized, and cheaper sensing platform for simultaneous quantifications of dopamine (DA), VMA, and HVA, with the aid of iron single-atom catalysts (Fe-SACs), based electrochemical sensor. SACs are atomically distributed metal atoms that have a maximum atomic utility rate of nearly 100%, compared to 30% for traditional metal nanoparticles. MXene sheets are employed to stabilize Fe-SACs, where, the exposed lone pairs of MXene serve as sites covalently linking high-energy single Fe atoms. MXene/Fe-SACs were synthesized by treating Ti3C2TxMXene with Iron chloride via freeze-drying followed by annealing. The successful formation of the material was verified by state-of-the-art characterizations. The MXene/Fe-SACs show superior electrocatalytic performance to the commonly used Fe- nanomaterials. Then, it was coated on the electrode surface and used to analyze DA, VMA, and HVA simultaneously via cyclic voltammetry (CV) and square-wave voltammetry (SWV). Under optimized conditions, the MXene/Fe-SACs electrochemical sensor showed detection limits as low as 1 nM and a linear range between 1 nM-100 μM for DA, LOD of 5 nM & linear range of 10 nM-100 μM VMA, and LOD of 10 nM & linear range of 20 nM-100 μM HAV. The method proved successful in detecting biomarkers in (spiked) synthetic urine and human serum. Furthermore, the method was successfully demonstrated in the determination of DA release from PC12 live cells, suggesting the wide practical use of SACs in sensing catecholamines-related metabolites.

by Perpetua E. Tan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1996. / Includes bibliographical references (leaves 149-157). / Abstract --- p.9 / Acknowledgments --- p.12 / List of abbreviations --- p.13 / List of Tables --- p.16 / List of Figures --- p.19 / Chapter CHAPTER 1 --- INTRODUCTION --- p.21 / Chapter CHAPTER 2 --- LITERATURE REVIEWS CATECHOLAMINES: NORADRENALINE AND ADRENALINE --- p.25 / Chapter 2.1 --- History --- p.25 / Chapter 2.2 --- Origin of plasma catecholamines --- p.25 / Chapter 2.3 --- Kinetics of entry and removal --- p.28 / Chapter 2.4 --- Levels present in plasma --- p.30 / Chapter 2.5 --- Some factors affecting plasma CA levels --- p.31 / Chapter 2.5.1 --- Effects of age --- p.31 / Chapter 2.5.2 --- Postural change --- p.32 / Chapter 2.5.3 --- Exercise --- p.32 / Chapter 2.5.4 --- Temperature change --- p.32 / Chapter 2.5.5 --- Stress --- p.33 / Chapter 2.5.6 --- Pregnancy --- p.34 / Chapter 2.5.7 --- Disease --- p.35 / Chapter 2.6 --- Actions in the body --- p.35 / Chapter 2.6.1 --- Plasma endogenous catecholamines --- p.35 / Chapter 2.6.2 --- Plasma exogenous catecholamines and medicine --- p.36 / Chapter 2.6.2.1 --- Clinical uses --- p.36 / Chapter 2.6.2.2 --- Effects --- p.37 / Chapter 2.6.2.3 --- Side effects --- p.38 / Chapter 2.7 --- Binding of catecholamines in plasma --- p.38 / Chapter 2.8 --- Measurement of catecholamines in plasma --- p.38 / Chapter 2.8.1 --- Chemistry --- p.38 / Chapter 2.8.2 --- Extraction and purification --- p.39 / Chapter 2.8.3 --- Biological methods --- p.40 / Chapter 2.8.4 --- Colorimetry --- p.41 / Chapter 2.8.5 --- Radioimmunoassay and radioenzymatic assay --- p.41 / Chapter 2.8.6 --- Enzyme-linked immunoassay --- p.42 / Chapter 2.8.7 --- Gas chromatography --- p.42 / Chapter 2.8.8 --- Liquid chromatography --- p.42 / Chapter 2.8.8.1 --- Fluorometry --- p.43 / Chapter 2.8.8.2 --- Electrochemical detection --- p.43 / Chapter 2.9 --- Plasma protein binding of basic drugs --- p.44 / Chapter 2.9.1 --- Binding to albumin --- p.45 / Chapter 2.9.2 --- Binding to alpha-1-acid-glycoprotein --- p.45 / Chapter 2.9.3 --- Binding to other proteins --- p.45 / Chapter 2.9.4 --- Factors affecting drug binding --- p.46 / Chapter 2.9.4.1 --- Pregnancy --- p.46 / Chapter 2.9.4.2 --- Age --- p.46 / Chapter 2.9.4.3 --- Disease states --- p.46 / Chapter 2.9.5 --- Separation procedures to reveal and follow drug protein binding --- p.47 / Chapter 2.9.5.1 --- Equilibrium dialysis --- p.47 / Chapter 2.9.5.2 --- Ultrafiltration --- p.48 / Chapter 2.9.5.3 --- Ultracentrifugation --- p.48 / Chapter 2.9.5.4 --- Gel Filtration --- p.48 / Chapter CHAPTER 3 --- ANALYTICAL TECHNIQUE : PLASMA CATECHOLAMINE ANALYSIS --- p.49 / Chapter 3.1 --- HPLC determination with coulometric detection of catecholamines --- p.49 / Chapter 3.1.1 --- Introduction --- p.49 / Chapter 3.1.2 --- Basic equipment --- p.49 / Chapter 3.1.3 --- Mobile phase preparation --- p.50 / Chapter 3.1.3.1 --- Reagent A (Citrate-acetate-EDTA buffer) --- p.50 / Chapter 3.1.3.2 --- Reagent B (ion pairing reagent) --- p.50 / Chapter 3.1.3.3 --- Mobile phase mixture --- p.50 / Chapter 3.1.4 --- Detector settings --- p.51 / Chapter 3.1.5 --- Sample collection and storage --- p.51 / Chapter 3.2 --- Reagents and solutions --- p.52 / Chapter 3.2.1 --- Acid-washed alumina --- p.52 / Chapter 3.2.2 --- Tris buffer solution --- p.53 / Chapter 3.2.3 --- Washing solution --- p.53 / Chapter 3.2.4 --- Acetic acid solution --- p.53 / Chapter 3.2.5 --- EDTA-HC1 solution --- p.53 / Chapter 3.2.6 --- Citric acid solution --- p.53 / Chapter 3.2.7 --- Stock solutions --- p.54 / Chapter 3.2.7.1 --- Catecholamine standards --- p.54 / Chapter 3.2.7.2 --- Dihydroxybenzylamine (Internal) standard --- p.54 / Chapter 3.2.8 --- Stripped fresh frozen plasma --- p.54 / Chapter 3.2.9 --- Sorensen's phosphate buffer containing 0.6% NaCl --- p.55 / Chapter 3.2.10 --- Control standards --- p.55 / Chapter 3.3 --- Voltammogram of catecholamines and internal standard used --- p.55 / Chapter 3.4 --- Maintenance of the HPLC-Coulometric detector system --- p.56 / Chapter 3.5 --- Optimization of the extraction method --- p.58 / Chapter 3.5.1 --- Amount of alumina for adsorption of CA --- p.58 / Chapter 3.5.2 --- pH of tris buffer for maximum uptake of CA onto alumina --- p.58 / Chapter 3.5.3 --- Optimum time for maximum uptake of CA onto alumina --- p.59 / Chapter 3.5.4 --- Optimum time for maximum desorption of CA into acid solution --- p.59 / Chapter 3.5.5 --- Optimum volume of acid solution for maximum desorption of CA --- p.60 / Chapter 3.6 --- Validation of the method --- p.60 / Chapter 3.6.1 --- Linearity --- p.60 / Chapter 3.6.2 --- Recovery --- p.61 / Chapter 3.6.3 --- Reproducibility --- p.62 / Chapter 3.6.4 --- Stability --- p.62 / Chapter 3.7 --- Results --- p.63 / Chapter 3.8 --- Discussion --- p.79 / Chapter CHAPTER 4 --- CLINICAL APPLICATIONS OF THE CATECHOLAMINE ASSAY --- p.84 / Chapter 4.1 --- Introduction --- p.84 / Chapter 4.1.1 --- Applications of catecholamines assay in clinical science --- p.84 / Chapter 4.2 --- : PLASMA CATECHOLAMINES AFTER INDUCTION OF ANAESTHESIA AT CAESARIAN SECTION --- p.84 / Chapter 4.2.1 --- Introduction --- p.84 / Chapter 4.2.2 --- Patients and methods --- p.86 / Chapter 4.2.3 --- Blood sampling and storage --- p.87 / Chapter 4.2.4 --- Statistics used --- p.87 / Chapter 4.2.5 --- Results --- p.88 / Chapter 4.2.6 --- Discussion --- p.99 / Chapter 4.3 --- EPINEPHRINE INFILTRATION IN SINUS SURGERY --- p.101 / Chapter 4.3.1 --- Introduction --- p.101 / Chapter 4.3.2 --- Patients and methods --- p.102 / Chapter 4.3.3 --- Blood sampling and storage --- p.103 / Chapter 4.3.4 --- Results --- p.104 / Chapter 4.3.5 --- Discussion --- p.108 / Chapter CHAPTER 5 --- ANALYTICAL TECHNIQUE: PLASMA PROTEIN BINDING OF CATECHOLAMINES --- p.110 / Chapter 5.1 --- Equilibrium dialysis for protein binding of drugs --- p.110 / Chapter 5.1.1 --- Introduction --- p.110 / Chapter 5.1.2 --- Dialyzing apparatus --- p.110 / Chapter 5.1.3 --- Sample collection and storage --- p.111 / Chapter 5.1.4 --- Reagents and solutions --- p.111 / Chapter 5.1.4.1 --- Ascorbic acid --- p.111 / Chapter 5.1.4.2 --- Glutathione --- p.111 / Chapter 5.1.4.3 --- Sodium metabisulfite --- p.111 / Chapter 5.1.4.4 --- Dialysis buffer --- p.111 / Chapter 5.1.5 --- Dialysis membrane --- p.112 / Chapter 5.1.6 --- Equilibrium dialysis --- p.112 / Chapter 5.2 --- Optimization of the binding parameters --- p.113 / Chapter 5.2.1 --- Types of preservatives for stability of catecholamines during dialysis --- p.113 / Chapter 5.2.2 --- Dialysis buffer --- p.114 / Chapter 5.2.3 --- Dialysis time and volume of sample --- p.114 / Chapter 5.2.4 --- Dialysis membrane --- p.115 / Chapter 5.2.5 --- Catecholamines concentration for dialysis --- p.114 / Chapter 5.3 --- Total protein analysis- Lowry Method --- p.115 / Chapter 5.3.1 --- Reagents and solutions --- p.116 / Chapter 5.3.1.1 --- Reagent A (Alkaline copper reagent) --- p.116 / Chapter 5.3.1.2 --- Reagent B (Folin-Ciocalteus phenol reagent with water) --- p.116 / Chapter 5.3.2 --- Stock standard and controls --- p.116 / Chapter 5.3.2.1 --- Human serum albumin standard --- p.116 / Chapter 5.3.2.2 --- Controls --- p.116 / Chapter 5.3.3 --- Procedure --- p.116 / Chapter 5.4 --- Results --- p.117 / Chapter 5.5 --- Discussion --- p.126 / Chapter CHAPTER 6 --- CONCLUSIONS --- p.130 / APPENDIX --- p.134 / CHEMICALS AND REAGENTS --- p.146 / REFERENCES --- p.149

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2009. / Härtill 6 uppsatser.

Diss. (sammanfattning) Stockholm : Karol inst.,2003. / Härtill 6 uppsatser.