Thesis (Ph. D.)--University of Hawaii at Manoa, 1990. / Includes bibliographical references (leaves 134-152) / Microfiche. / xvi, 152 leaves, bound ill. 29 cm

En hématologie, des tensioactifs tels que les saponines sont utilisés comme agent érythrolytique afin de compter et identifier les différentes populations de globules blancs, qui sont mille fois moins abondants que les érythrocytes. Ces saponines sont utilisées pour leur lyse sélective des globules rouges dans les réactifs d’HORIBA Médical. Au cours de cette thèse, nous avons étudié l’action de différents tensioactifs sur les cellules sanguines afin d’avoir une meilleure compréhension des interactions tensioactifs/membrane. Le premier projet a porté sur l’observation et la caractérisation des effets des saponines sur les érythrocytes par des méthodes microscopiques et spectrophotométriques, dans le but d’obtenir une meilleure compréhension de leur sélectivité vis-à-vis des globules rouges. Nous avons ainsi démontré la participation du cholestérol, des transporteurs tels que la bande 3 et du cytosquelette lors de la lyse par les saponines. Dans une seconde étude, des recherches ont été entreprises afin d’identifier les propriétés requises d’un tensioactif pour obtenir un agent lytique efficace. Nous avons sélectionné deux types de familles de tensioactifs, l’une non-ionique de type éther d’alcool polyoxyéthylèné, et l’autre anionique à base d’acides aminés. Ces études se sont concentrées sur la relation entre le pouvoir érythrolytique et certains paramètres physico-chimiques des tensioactifs tels que la concentration micellaire critique (CMC), la balance hydrophile-lipophile (HLB), le coefficient de partage entre la membrane et le milieu aqueux (Kb), et le packing parameter (P). Nous avons montré qu’une considération globale de l’ensemble de ces paramètres était nécessaire pour pouvoir prédire les interactions des tensioactifs avec la membrane des érythrocytes. Enfin, l’effet lytique de ces tensioactifs sur les leucocytes a été étudié en cytométrie en flux afin de vérifier l’intégrité des globules blancs lors des différentes lyses. Les résultats obtenus au cours de ces travaux de thèse rendent possible le développement de futurs réactifs hématologiques pour la différenciation leucocytaire. / Surfactants such as saponins are employed, in the haematology field, as erythrolytic agent in order to count and to identify different leukocyte populations, which are typically thousand times less abundant than erythrocytes. These saponins are used for erythrocytes selective lysis in HORIBA Medical reagents. This thesis aimed to study the action of different surfactants on red blood cells in order to have a better understanding of surfactants/membrane interactions. The first project involved the observation and the characterization of saponins effects on erythrocytes by microscopic and spectrophotometric methods, in order to understand saponins selectivity regarding erythrocytes. We have thus demonstrated the participation of cholesterol, transporters such as band 3 and erythrocyte cytoskeleton during saponins lysis. In a second study, investigations have been performed in order to identify surfactants properties required to get a suitable erythrocyte lysing agent. We have chosen two surfactants families: non-ionic surfactants of the polyoxyethylene alkyl ethers series and anionic amino acid-based surfactants. These studies are focused on the relation between surfactants erythrolytic potency and some physico-chemical parameters such as the critical micellar concentration (CMC), the hydrophile-lipophile balance (HLB), the surfactants membrane / water partition coefficient (Kb) and the packing parameter (P). We have thus shown that the global consideration of all these physico-chemical parameters was necessary to predict surfactants interactions with the erythrocytes membrane. Finally, the lytic effects of surfactants on leukocytes were studied in flow cytometry to verify leukocytes integrity during different lysis. The results obtained in this thesis make possible the future development of hematological reagent for leukocytes differentiation.

Previous studies on the medical use of ozone therapies show a very diverse array of results, from ozone reducing the amount of HIV virus in the blood, to no effect, to causing the death of several patients due to pulmonary embolism and infections. However, ozone therapies are widely used in Europe and considered medically safe. In the U.S., doctors in 28 states use ozone therapies. The objectives of this study were to investigate the effects of medical grade ozone at varying concentrations used in ozone therapies. These were achieved by evaluating the C-reactive protein, erythrocyte sedimentation rate, total reduced and oxidized glutathione content of erythrocytes which were all markers used to determine ozone injury/inflammation. Despite the fact that ozone is a very strong oxidant, previous research indicates that depending on the dose and the health status of the biological system, sometimes ozone can act as an antioxidant. The medical exposure range for ozone is between 20-80 mg/ml with an average of 50 mg/ml. The concentrations used in this study were 20, 40, 80 and 160 mg/ml. Ozone was generated in the "Breath Lab" at USF from medical grade oxygen obtained through electrical corona arc discharge using an OL80C ozone generator. De-identified blood samples of 10 ml blood/sample containing EDTA as anticoagulant were obtained from the James A. Haley VA Hospital patients. Equal volumes of blood and ozone gas mixture were allowed to mix in ozone-resistant syringes prior to dividing each sample into three parts, one for each corresponding parameter to be studied. The C-reactive protein was analyzed through ELISA using the colorimetric method available from Helica Biosystems; erythrocyte sedimentation rate was measured in graduated sedimentation tubes; the total reduced glutathione (GSH) and oxidized glutathione (GSSG) content of erythrocytes was determined according to the colorimetric method developed by the Oxford Biomedical Research. Overall, the concentrations of ozone used did not have a statistically significant effect on the parameters investigated. However, a small percentage of the blood samples showed an improvement in the parameters studied, especially at the highest ozone concentration.

Charles University University of Porto Faculty of Pharmacy in Hradec Králové Faculty of Pharmacy Department of Pharmacology and Toxicology Department of Biological Sciences Student: Karolína Zubatá Supervisor: doc. PharmDr. Martina Čečková, Ph.D. Consultants: Susana Rocha, Ph.D., prof. Alice Santos-Silva, Ph.D. Title of diploma thesis: Oxidative stress biomarkers of the erythrocyte in the newborn - a follow-up study Increased levels of oxidative stress (OS) have been described in healthy, full-term newborns as a consequence of the drastic changes introduced by birth and by the exposure to extrauterine environment. Our intention was to examine the OS levels in red blood cells (RBCs) of neonates and to further understand the changes that the newborn organism undergoes with its newly- acquired autonomy as this knowledge is limited and there are no reference values. Umbilical cord blood samples were collected from a small population of newborns (n = 8) and several hematological and biochemistry parameters were evaluated. Our experimental data consist of OS biomarkers measurements performed in different fractions of blood (RBC membrane, total RBCs and plasma): membrane bound hemoglobin (MBH), lipid peroxidation (LPO), quantification of catalase (CAT) and glutathione peroxidase (GPx) activities,...

京都大学 / 0048 / 新制・課程博士 / 博士(生命科学) / 甲第18626号 / 生博第317号 / 新制||生||42(附属図書館) / 31526 / 京都大学大学院生命科学研究科統合生命科学専攻 / (主査)教授 上村 匡, 教授 西田 栄介, 教授 James Hejna / 学位規則第4条第1項該当 / Doctor of Philosophy in Life Sciences / Kyoto University / DGAM

Exposure of human erythrocytes to elevated intracellular calcium causes alterations in cell shape and stimulates shedding of the cell membrane in the form of microvesicles. We hypothesized that both the shape transition and microvesiculation are influenced by microscopic membrane physical properties such as lipid order. To test this hypothesis, membrane properties were manipulated by varying the experimental temperature, membrane cholesterol content, and the internal ionic environment. Changes in membrane order were assessed using steady-state fluorescence spectroscopy with an environment-sensitive probe, laurdan. Our observations led us to the following conclusions: 1) the modest temperature dependence of membrane structure observed with laurdan is shifted to lower temperatures and becomes more cooperative upon removal of membrane cholesterol, 2) the calcium-induced shape change observed in erythrocytes requires a decrease in membrane order, 3) the influence of membrane order is not limited to shape transitions induced only by calcium, and 4) decreased order is also a permissive factor for microvesicle shedding. Our data suggest that while the mechansims that regulate the shape transition and the release of microvesicles are different, they both require a state of membrane disorder.

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Fresh isolated erythrocyte ghost membranes and erythrocyte suspensions were incubated with an organic hydroperoxide, tert-butyl hydroperoxide, to establish the in vitro oxidative stress models. Circulating erythrocytes from normal individuals were fractionated into subpopulations of different ages by ultracentrifugation and used as an in vivo model. In these models, membrane iPF2alpha-III content accumulation was proportional to oxidative stress and correlated with decreased membrane fluidity. In circulating erythrocytes, membrane iPF2alpha-III increased with age and inversely correlated with membrane fluidity only in the core region. / Oxidative stress is involved in the pathophysiology of a wide variety of human diseases. Isoprostanes, a family of prostaglandin derivatives, are mainly derived from free radical peroxidation of specific polyunsaturated fatty acids (PUFA). Measurement of F2-isoprostanes (F2-iPs) or one specific biologically active isomer (iPF2alpha-III) is considered to be a reliable lipid peroxidation marker in human diseases. However, the association observed between increased plasma/urine F2-iPs and diseases does not necessarily reflect tissue oxidative damages. Circulating erythrocytes, a tissue with limited biosynthetic capacity and poor repair mechanism, would offer a number of advantages for assessment of in vivo oxidative damages. In this thesis, human erythrocyte membrane iPF2alpha-III content was investigated as a new marker for in vivo oxidative stress assessment. Membrane fluidity was used as an indirect marker of cellular function. / To use membrane iPF2alpha-III in a human disease with known oxidative stress burden, 49 Chinese patients on long-term haemodialysis and 31 healthy Chinese subjects were recruited. Both plasma and membrane iPF 2alpha-III showed that haemodialysis patients had increased oxidative stress. Only membrane iPF2alpha-III, but not the conventional used plasma iPF2alpha-III, correlated with membrane fluidity. Furthermore, the significant inverse correlation between membrane iPF 2alpha-III and the core region of membrane fluidity was observed for this group of patients too. Since membrane iPF2alpha-III was shown to provide a link between oxidative stress and erythrocyte function, it would be considered as a new marker of in vivo erythrocyte oxidative stress assessment. (Abstract shortened by UMI.) / Yu Xiongwen. / "July 2005." / Advisers: Wai Kei Christopher Lam; Chung Shun Ho. / Source: Dissertation Abstracts International, Volume: 67-07, Section: B, page: 3724. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (p. 198-223). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract in English and Chinese. / School code: 1307.