Studies on catecholamines and 5-hydroxytryptamine and the significance of their metabolites in animal tissues and body fluids

The papers presented in this thesis describe the development of methods for the estimation of adrenaline, noradrenaline, dopamine, 5-hydroxytryptamine and some of their metabolites and the application of such estimations to some problems of biological interest. The major part of the thesis is concerned with the metabolism of these amines in the mammalian central nervous system. The papers are presented in three groups.The first group is made up of papers in which the estimation of 5-hydroxytryptamine (5-HT) or its metabolite 5-hydroxy-indol-3-yl acetic acid (5-HIAA) was measured.1. On the question of the occurrence and metabolism of 5-hydroxy-tryptamine and related indole compounds in mammalian semen. By T. Mann, R. P. Seamark and D. F. Sharman. Br. J. Pharmac. Chemother. 17, 208 - 217, 1961.In this paper it was shown conclusively that the semen of man, bull, boar, ram and dog contains little or no 5-hydroxytryptamine.2. Drug-induced changes in the concentration of 5-0R indolyl compounds in cerebrospinal fluid and caudate nucleus. By G. V. Ashcroft and D. P. Sharman. Br. J. Pharmac. Chemother. 19. 155 - 160, 1962.Because of an earlier observation by Ashcroft and Sharman (Nature, Lond.,186, 1050 - 1051, i960) that the cerebrospinal fluid of depressed patients contained a lower concentration of 5-hydroxyindolyl compounds than normal, the effect of reserpine, a drug known to reduce the concentration of 5-hydroxytryptamine in the brain, on the concentration of such compounds in the cerebrospinal fluid of the dog was examined. It was found that the concentration of 5-hydroxyindolyl compounds in the cerebrospinal fluid was increased after reserpine.3. The effect of a-methyldopa on the metabolism of 5-hydroxy-tryptamine in rat brain. By D. P. Sharman and S. E. Smith. J. Neurochem. 403 - 406, 1962.In this paper, the concentration of 5-HIAA in the brain was used as an index of the rate at which 5-HT was released in this tissue after a-methyldopa, an inhibitor of the formation of 5-HT,was given to rats.4. The action of 2-aminotetralin ({3-tetrahydronaphthylamine) on the metabolism of 5-hydroxytryptamine in the brain of the mouse. By D. Robinson and D. P. Sharman. Br. J. Pharmao. Chemother. 29. 535 - 341, 1967.2-Aminotetralin causes a reduction in the concentration of 5- hydroxyindol-3-ylacetic acid in the brain of the mouse (paper 12). The possible causes of this effect were' examined.The second group consists mainly of papers which describe the development of methods of estimating dopamine and its acid metabolites 3,4-dihydroxyphenylacetio acid (DOPAC) and 4-hydroxy-3-methoxyphenyl acetic acid (homovanillic acidj HVA), their application to several problems, chiefly to a study of the rate of utilisation of dopamine in the brain and also the effect of drugs on the metabolism of this amine.5. Chemical and physiological changes produced by arterial infusion of dihydroxyphenylalanine into one cerebral hemisphere of the cat. By R. Dagirmanjian, R. Laverty, P. Mantegazzini, D. P. Sharman and M. Vogt. J. Neurochem. 10, 177 - 182, 1965.The infusion of 3,4-dihydroxyphenylalanine (DOPA) into one carotid artery of the cat can cause arousal of the brain on the side of the infusion. It was shown that this unilateral arousal is accompanied by an increase in the concentration of dopamine in the caudate nucleus, hypothalamus and midbrain reticular formation on the same side of the brain.6. The subcellular localisation of dopamine and acetylcholine in the dog caudate nucleus. By R. Laverty, I. A. Michaelson, D.P. Sharman and V. P. Whittaker. Br. J. Pharmac. Chemother. 21, 482 - 490, 1963.7. Localisation of acetylcholine, 5-hydroxytryptamine and noradrenaline within subcellular particles derived from guinea-pig subcortical brain tissue. By I. A. Michaelson, V. P. Whittaker, R. Laverty and D. P. Sharman. Biochem. Pharmacol. 12. 1450-1453, 1963.8. A fluorimetric method for the estimation ti 4-hydroxy-3-methoxyphenylacetic acid (homovanillic acid) and its identification in brain tissue. By D. F. Sharman. Br. J. Pharinac. Chemother. 20. 204 - 213, 1963.9. The estimation of small quantities of 3,4-dihydroxyphenylethylamine in tissues. By R. Laverty and D. F. Sharman. Br. J. Pharmac. Chemother. 24, 538 - 548, 1965.10. Modification by drugs of the metabolism of 3,4-dihydroxyphenylethylamine, noradrenaline and 5-hydroxytryptamine in the brain. By R. Laverty and D. F. Sharraan. Br. J. Pharmac. Chemother. 24. 759 - 772, 1965.11. The effect of drugs on the homovanillie aoid content of the corpus striatum of some rodents. By A. V. Juorio, D. F. Sharman and T. Trajkov. Br. J. Pharmac. Chemother. 26. 385 - 392, 1966.12. Changes in the metabolism of 3,4-dihydroxyphenylethylamine (dopamine) in the striatum of the mouse induced by drugs. By D. F. Sharman, Br. J. Pharmac. Chemother. 28. 153 - 163, 1966.13. A discussion of the modes of action of drugs which increase the concentration of 4-hydroxy-3-methoxyphenylacetic acid (homovanillic acid) in the striatum of the mouse. By D. P. Sharman. Br. J. Pharmac. Chemother. 30, 620 - 626, 1967.14. Homovanillic acid and dihydroxyphenylacetic acid in the striatum of monkeys with brain lesions. By D. P. Sharman, L. J. Poirier, G. P. Murphy and T. L. Sourkes. Can. J. Physiol. Pharmacol. 49. 57 - 62, 1967.15. Release by tubocurarine of dopamine and homovanillic acid from the superfused caudate nucleus. By P. J. Portig, D. P. Sharman and Marthe Vogt. J. Physiol. Lond. 194. 565 - 572, 1968.16. The effect of tropolone on the formation of 3,4-dihydroxyphenylacetic acid and 4-hydroxy-3-methoxyphenylacetic acid in the brain of the mouse. By G. P. Murphy, D. Robinson and D. P. Sharman. Br. J. Pharmac. Chemother. j>6, 107 - 115, 1969.17. Turnover of amines using probenecid to block the egress of metabolites. By D. P. Sharman. Metabolism of brain amines. Edited by G. Hooper, Macmillan, London, pp. 34 - 37, 1969.These papers form the main part of the thesis and attempt to relate the concentration of HVA in the central nervous system to the rate at which dopamine is utilised in this tissue. The locus of the metabolism of dopamine in the central nervous system is discussed.The papers in the third group are concerned with noradrenaline or its glycol metabolites.18. Noradrenaline content in the heart and spleen of the mouse tinder normal conditions and after administration of some drugs. By D. P. Sharman, S. Vanov and Marthe Vogt. Br. J. Pharmac. Chemother. 11, 527 - 533, 1962.This study was made to investigate a report of what appeared to he unusual behaviour of the tissue catecholamines in the mouse. The method used to estimate the noradrenaline was designed to incorporate as many controls as was possible to ensure that correct estimates were obtained. The earlier report could not be confirmed.19. Iontophoretic release of adrenaline noradrenaline and 5-hydroxytryptamine from raicropipettes. By K. Krnjevic, R. Laverty and D. P. Sharman. Br. J. Pharmac. Chemother. 20, 491 - 496, 1963.Fluorimetric methods were used to measure the relation between the release of these amines and the electrical charge applied to micropipettes used for the iontophoretic application of drugs to single neurones.20. The action of 2,4,5-trihydroxyphenylethylamine on the storage and release of noradrenaline. By R. Laverty, D. P. Sharman and Marthe Vogt. Br. J. Pharmac. Chemother. 24, 549 - 560, 1965.2,4,5-Trihydroxyphenylethylamine causes a rapid and long lasting depletion of noradrenaline from the mouse heart. A new method was developed for the estimation of the former amine and was used to show that it did not persist in the tissue or was tightly bound in the tissue.21. The noradrenaline content of the caudate nucleus of the rabbit. By D. P. Sharman and Marthe Vogt. J. Neurochem. 12. 62, 1965.This short paper illustrates a frequently reported erroneous result when a commonly used fluorimetric method for the estimation of nor-adrenaline is applied to those brain tissues which contain very little of this amine.22. Gas chromatographic evidence for the presence of glycol metabolites of catecholamines in brain tissue. By B. F. Sharman. J. Physiol. Lond. 200. 35 - 35P, 1969.23. Glycol metabolites of noradrenaline in brain tissue. By D. P. Sharman. Accepted for publication by Br. J. Pharmac. Chemother. 1969.The application of gas liquid chromatography and electron capture detection to the estimation of glycol metabolites of noradrenaline in the brain is described. The possibility of using a similar technique for the estimation of noradrenaline and normetanephrine is discussed.These two papers describe the estimation of noradrenaline, dopamine, 5-hydroxytryptamine and acetylcholine in particles obtained by sub-cellular fractionation of brain tissues. The first shows that dopamine is associated with a particle that is similar to,but distinguish¬ able from, that with which acetylcholine is associated. The second paper demonstrates that the storage sites within subcellular particles for acetylcholine and those for noradrenaline and 5-hydroxytryptamine are different

Exploring access to end of life care for ethnic minorities with end stage kidney disease through recruitment in action research

BACKGROUND: Variation in provision of palliative care in kidney services and practitioner concerns to provide equitable access led to the development of this study which focussed on the perspectives of South Asian patients and their care providers. As people with a South Asian background experience a higher risk of Type 2 Diabetes (T2DM) and end stage kidney failure (ESKF) compared to the majority population but wait longer for a transplant, there is a need for end of life care to be accessible for this group of patients. Furthermore because non English speakers and people at end of life are often excluded from research there is a dearth of research evidence with which to inform service improvement. This paper aims to explore issues relating to the process of recruitment of patients for a research project which contribute to our understanding of access to end of life care for ethnic minority patients in the kidney setting. METHODS: The study employed an action research methodology with interviews and focus groups to capture and reflect on the process of engaging with South Asian patients about end of life care. Researchers and kidney care clinicians on four NHS sites in the UK recruited South Asian patients with ESKF who were requiring end of life care to take part in individual interviews; and other clinicians who provided care to South Asian kidney patients at end of life to take part in focus groups exploring end of life care issues. In action research planning, action and evaluation are interlinked and data were analysed with emergent themes fed back to care providers through the research cycle. Reflections on the process of patient recruitment generated focus group discussions about access which were analysed thematically and reported here. RESULTS: Sixteen patients were recruited to interview and 45 different care providers took part in 14 focus groups across the sites. The process of recruiting patients to interview and subsequent focus group data highlighted some of the key issues concerning access to end of life care. These were: the identification of patients approaching end of life; and their awareness of end of life care; language barriers and informal carers' roles in mediating communication; and contrasting cultures in end of life kidney care. CONCLUSIONS: Reflection on the process of recruitment in this action research study provided insight into the complex scenario of end of life in kidney care. Some of the emerging issues such as the difficulty identifying patients are likely to be common across all patient groups, whilst others concerning language barriers and third party communication are more specific to ethnic minorities. A focus on South Asian ethnicity contributes to better understanding of patient perspectives and generic concepts as well as access to end of life kidney care for this group of patients in the UK. Action research was a useful methodology for achieving this and for informing future research to include informal carers and other ethnic groups.Peer reviewedFinal Published versio

Increased light, moderate, and severe clear-air turbulence in response to climate change

Anthropogenic climate change is expected to strengthen the vertical wind shears at aircraft cruising altitudes within the atmospheric jet streams. Such a strengthening would increase the prevalence of shear instabilities, which generate clear-air turbulence. Climate modelling studies have indicated that the amount of moderate-or-greater clear-air turbulence on transatlantic flight routes in winter will increase significantly in future as the climate changes. However, the individual responses of light, moderate, and severe clear-air turbulence have not previously been studied, despite their importance for aircraft operations. Here we use climate model simulations to analyse the transatlantic wintertime clear-air turbulence response to climate change in five aviation-relevant turbulence strength categories. We find that the probability distributions for an ensemble of 21 clear-air turbulence diagnostics generally gain probability in their right-hand tails when the atmospheric carbon dioxide concentration is doubled. By converting the diagnostics into equivalent eddy dissipation rates, we find that the ensemble-average airspace volume containing light clear-air turbulence increases by 59% (with an intra-ensemble range of 43–68%), light-to-moderate by 75% (39–96%), moderate by 94% (37–118%), moderate-to-severe by 127% (30–170%), and severe by 149% (36–188%). These results suggest that the prevalence of transatlantic wintertime clear-air turbulence will increase significantly in all aviation-relevant strength categories as the climate changes

Principal Findings of the Invasive Blood Pressure Meta-Analysis Consortium (Inspect) on the Accuracy of Brachial Cuff Blood Pressure Devices

OBJECTIVE: Accurate measurement of blood pressure (BP) is crucial for hypertension management. Accuracy of brachial cuff (B_CUFF) devices to measure invasive (intra-arterial) BP at the brachial artery (B_INV) and aorta (A_INV) has never been systematically assessed. This study aimed to determine the: 1) relationship between B_INV and A_INV; 2) accuracy of B_CUFF devices to estimate invasive BP and; 3) accuracy of B_CUFF devices to classify BP thresholds. DESIGN AND METHOD: Three individual patient meta-analyses (by search of online databases and systematic review supplemented by measurements in a tertiary hospital cardiac catheterization laboratory) were performed to determine: 1) B_INV versus A_INV BP; 2) B_CUFF versus B_INV BP and A_INV BP and; 3) B_CUFF for BP classification versus invasive BP. RESULTS: Most subjects (90%) were patients undergoing cardiac catheterization (total N = 3004; mean age 58.7 years, 95%CI [54.0, 63.4], 68% male). As shown in the table: 1) B_INV systolic BP (SBP) was significantly higher than A_INV SBP whilst A_INV diastolic BP (DBP) was slightly higher than B_INV DBP. 2) B_CUFF underestimated B_INV SBP and overestimated B_INV DBP. The mean difference between B_CUFF SBP and A_INV SBP was small, whilst B_CUFF DBP overestimated A_INV DBP. However, according to mean absolute difference, B_CUFF and A_INV showed poor agreement. 3) B_CUFF correctly classified 31.1/28.4% of high-normal (SBP 130–139 mmHg), 54.2/52.6% of grade I (SBP 140–159 mmHg) and 45.2/50.3% of grade II (SBP 160–179 mmHg) hypertension cases, using B_INV/A_INV, respectively, as the reference. Correct classification was more frequent for SBP B_CUFF values 75%). CONCLUSIONS: While recognising the clinical importance of B_CUFF devices, there is wide variability in device accuracy for measuring intra-arterial BP. Although B_CUFF devices are reasonable for correctly classifying BP at low and very high BP thresholds, more accurate B_CUFF devices in the high-normal BP to grade II hypertension range should improve hypertension management

A potent nonporphyrin class of photodynamic therapeutic agent: cellular localisation, cytotoxic potential and influence of hypoxia

We have developed a totally new class of nonporphyrin photodynamic therapeutic agents with a specific focus on two lead candidates azadipyrromethene (ADPM)01 and ADPM06. Confocal laser scanning microscopy imaging showed that these compounds are exclusively localised to the cytosolic compartment, with specific accumulation in the endoplasmic reticulum and to a lesser extent in the mitochondria. Light-induced toxicity assays, carried out over a broad range of human tumour cell lines, displayed EC50 values in the micro-molar range for ADPM01 and nano-molar range for ADPM06, with no discernable activity bias for a specific cell type. Strikingly, the more active agent, ADPM06, even retained significant activity under hypoxic conditions. Both photosensitisers showed low to nondeterminable dark toxicity. Flow cytometric analysis revealed that ADPM01 and ADPM06 were highly effective at inducing apoptosis as a mode of cell death. The photophysical and biological characteristics of these PDT agents suggest that they have potential for the development of new anticancer therapeutics

The Play Behaviours of Roma Children in Transylvania

The Roma children of Transylvania are probably the most materially deprived in Europe. They often live in one-room shacks made from wood and mud, with no running water, no sanitation, and sometimes no heating. Many rely on charity for their food and medicines. But, are they play deprived? This paper summarises an observational study of the play behaviours of children in a small Roma village. It highlights the striking contrast between the abject poverty that characterises their lives and the general happiness of the children. These children live their limited lives to the full. They ‘play everywhere and with everything’, but not in the generally accepted sense of that phrase. The usual niceties of privacy, personal possessions and property boundaries are irrelevant here. Their play is rich in imagination and creativity; it is living proof of Nicholson’s theory of loose parts

Fatigue life of machined components

A correlation between machining process and fatigue strength of machined components clearly exists. However, a complete picture of the knowledge on this is not readily available for practical applications. This study addresses this issue by investigating the effects of machining methods on fatigue life of commonly used materials, such as titanium alloys, steel, aluminium alloys and nickel alloys from previous literature. Effects of turning, milling, grinding and different non-conventional machining processes on fatigue strength of above-mentioned materials have been investigated in detail with correlated information. It is found that the effect of materials is not significant except steel in which phase change causes volume expansion, resulting in compressive/tensile residual stresses based on the amounts of white layers. It is very complex to identify the influence of surface roughness on the fatigue strength of machined components in the presence of residual stresses. The polishing process improves the surface roughness, but removes the surface layers that contain compressive residual stresses to decrease the fatigue strength of polished specimens. The compressive and tensile residual stresses improve and reduce fatigue strength, respectively. Grinding process induces tensile residual stresses on the machined surfaces due to high temperature generation. On the other hand, milling and turning processes induce compressive residual stresses. High temperature non-conventional machining generates a network of micro-cracks on the surfaces in addition to tensile residual stresses to subsequently reduce fatigue strength of machined components. Embedded grits of abrasive water jet machining degrade the fatigue performance of components machined by this method