Thèses sur le sujet « Human ferritin »

Thesis (M.S.)--West Virginia University, 2002.
Title from document title page. Document formatted into pages; contains vi, 43 p. Vita. Includes abstract. Includes bibliographical references (p. 34-36).

Athletes commonly use altitude exposure in an attempt to improve their aerobic performance at sea level. Altitude exposure enhances erythropoiesis and iron-dependent oxidative and glycolytic enzyme production, for this reason, athletes must maintain a healthy iron balance at altitude. A negative iron balance at altitude may limit such physiological adaptations, potentially reducing the performance benefits of altitude exposure. This thesis examined the regulation of iron metabolism during acute (~31 min, Study One) and prolonged altitude exposure (14 days, Study Two). Finally, Study Three examined how daily oral iron supplementation influenced haemoglobin mass (Hbmass) and iron parameter responses to prolonged, moderate altitude exposure in a large cohort of elite athletes. Specifically, Study One found acute (~31 min) interval exercise [5 × 4 min at 90% of the maximal aerobic running velocity (vVO2max)] increased post-exercise interleukin-6 (IL-6) production and elevated hepcidin production 3 h thereafter in both normoxia (fraction of inspired oxygen (FIO2) = 0.2093) and normobaric hypoxia (i.e. 3,000 m simulated altitude; FIO2 = 0.1450). These results suggest exercise performed in acute hypoxia does not alter the post-exercise hepcidin response, relative to exercise in normoxia, possibly owing to the short duration of the hypoxic stimulus. Prolonged altitude exposure suppresses resting hepcidin levels in sojourning mountaineers, but its influence on the post-exercise hepcidin response exercise has not yet been investigated. Therefore, Study Two investigated how 14 days of live high: train low (LHTL) (exposure to 3,000 m simulated altitude for 14 h.d-1) influenced resting levels of hepcidin, erythropoietin (EPO) and blood iron parameters. Study Two also examined the post-exercise hepcidin and iron parameter responses to interval exercise (5 × 1,000 m at 90% of the maximal aerobic running velocity) performed in normoxia (600 m natural altitude) and normobaric hypoxia (i.e. ~3,000 m simulated altitude), following 11 and 14 days of LHTL. The post-exercise hepcidin response was compared with interval exercise performed at a matched exercise intensity in normoxia or hypoxia before LHTL. Here, LHTL suppressed resting hepcidin levels after two days of exposure, but the post-exercise hepcidin response to interval exercise was similar in normoxia and hypoxia, both before and after LHTL. Additionally, Hbmass increased by 2.2% and plasma ferritin levels decreased following LHTL. In conclusion, prolonged, moderate altitude exposure suppresses resting hepcidin levels, which likely ensures more iron can be transported to the erythron to support accelerated erythropoiesis. Prolonged altitude exposure places a large burden on body iron stores because additional iron is required to support accelerated erythropoiesis. Accordingly, athletes often ingest oral iron supplements during altitude exposure to ensure they maintain a healthy iron balance. By analysing ten years of haematological data collected from welltrained athletes who undertook two-to-four weeks of LHTL at simulated (3,000 m) or natural (1,350-2,700 m) altitudes, Study Three established how oral iron supplement dose moderates the Hbmass, serum ferritin and transferrin saturation response to prolonged moderate altitude exposure. In general, athletes supplemented with 105 mg.d- 1 or 210 mg.d-1 of oral iron supplement increased their Hbmass from pre-altitude levels by 3.3% and 4.0% respectively. Serum ferritin levels decreased by 33.2% in non-iron supplemented athletes and by 13.8% in athletes supplemented with 105 mg.d-1 of oral iron, however, those athletes who ingested 210 mg.d-1 markedly increased their iron storage compartment by 36.8% after moderate altitude exposure. Thus, daily oral iron supplementation at altitude assists athletes to maintain a healthy iron balance, providing them with sufficient iron to sustain accelerated erythropoiesis. In conclusion, this thesis suggests exercise in acute hypoxia does not seem to alter the post-exercise hepcidin response relative to exercise in normoxia, but prolonged altitude exposure suppresses resting hepcidin levels and may attenuate the magnitude of postexercise hepcidin response after 14 days of LHTL. Finally, daily oral iron supplementation may support iron balance and Hbmass production in athletes undertaking prolonged moderate altitude exposure.

Iron deficiency anemia is the most common nutritional deficiency disease worldwide (Mahan & Escott-Stump, 2004). Iron deficiency anemia is of major concern especially in women of child bearing age and those who follow a vegetarian diet. The objective of this study was to compare the nutrient and hematological values related to iron status in female university students following a vegetarian versus following a nonvegetarian diet. This study took a cross sectional analysis of 39 female students at California Polytechnic State University (Cal Poly State University) in San Luis Obispo, CA. Of the participants 19 were following a vegetarian diet and 20 were following a nonvegetarian diet. To participate, individuals had to be female, current Cal Poly students, and between the ages of 18 and 22 years old. Those taking vitamin or mineral supplements, medications (including oral contraceptives), smokers, and pregnant women were excluded. Characteristic, demographic, and anthropometric data were collected through interview, nutrient intake was accessed by averaging three day food records, and hematological parameters were measured. Statistical analysis used nonparametric techniques including the Mann-Whitney Wilcoxon statistical test for demographics and baseline characteristics, the Spearman Rank Correlation analysis and Fisher’s Exact statistical test for associations between vegetarians and nonvegetarians. Results found no significant difference in iron intake between vegetarians and nonvegetarians, however nonvegetarians had higher mean intakes of iron at 16.82 (SD 6.36) mg/day compared to vegetarians at 14.84 (SD 7.10) mg/day (p=0.482). A similar percentage of vegetarians at 66.7% (n=8) compared to nonvegetarians at 65% (n=13) were under the Recommended Daily Allowance (18 mg per day for females 19 to 30 years of age) for mean iron consumption. There were slightly more nonvegetarians at 10% (n=2) compared to vegetarians at 8.3% (n=1) under the Estimated Average Requirement (8.1 mg/day for females 19 to 30 years of age) for mean iron intake. No significant difference was found for serum iron, serum ferritin, transferrin saturation, and total iron binding capacity between vegetarians and nonvegetarians. Finding revealed serum ferritin, the most common iron status indicator, was lower for vegetarians at 23.16 (SD15.54) ng/mL compared to nonvegetarians at 27.75 (SD 18.01) ng/mL (p=0.47). When looking at the stages of iron balance, there was greater percentage of vegetarians with hematological results (serum iron <40 µg/dL, total iron binging capacity of >410 µg/dL, transferrin saturation <15%, and serum ferritin <10 ng/mL) indicating iron deficiency anemia or stage IV negative iron balance compared to nonvegetarians. There was no significant correlation between iron intake and serum ferritin, however results showed a positive association (r=0.28, p=0.09). In conclusion, vegetarian participants are believed to be at higher risk of developing negative iron balance compared to nonvegetarians due to lower iron consumption and lower serum ferritin concentrations. Female university students following a vegetarian diet should be educated on iron deficiency anemia and prevention of iron depletion.

Triple A syndrome is caused by mutations in AAAS encoding the protein ALADIN. We investigated the role of ALADIN in the human adrenocortical cell line NCI-H295R1 by either over-expression or down-regulation of ALADIN. Our findings indicate that AAAS knock-down induces a down-regulation of genes coding for type II microsomal cytochrome P450 hydroxylases CYP17A1 and CYP21A2 and their electron donor enzyme cytochrome P450 oxidoreductase, thereby decreasing biosynthesis of precursor metabolites required for glucocorticoid and androgen production. Furthermore we demonstrate that ALADIN deficiency leads to increased susceptibility to oxidative stress and alteration in redox homeostasis after paraquat treatment. Finally, we show significantly impaired nuclear import of DNA ligase 1, aprataxin and ferritin heavy chain 1 in ALADIN knock-down cells. We conclude that down-regulating ALADIN results in decreased oxidative stress response leading to alteration in steroidogenesis, highlighting our knock-down cell model as an important in-vitro tool for studying the adrenal phenotype in triple A syndrome.

The aim of this thesis was to study maternal and infant effects of delayed cord clamping (≥180 seconds, DCC) compared to early (≤10 seconds, ECC) in a randomised controlled trial. Practice and guidelines regarding when to clamp the cord vary globally, and different meta-analyses have shown contradictory conclusions on benefits and disadvantages of DCC and ECC. The study population consisted of 382 term infants born after normal pregnancies and randomised to DCC or ECC after birth. The primary objective was iron stores and iron deficiency at 4 months of age, but the thesis was designed to investigate a wide range of suggested effects associated with cord clamping. Paper I showed that DCC was associated with improved iron stores at 4 months (45% higher ferritin) and that the incidence of iron deficiency was reduced from 5.7% to 0.6%. Neonatal anaemia at 2-3 days was less frequent in the DCC group, 1.2% vs. 6.3%. There were no differences between the groups in respiratory symptoms, polycythaemia, or hyperbilirubinaemia. In paper II we demonstrated that DCC versus ECC was not associated with higher risk for maternal post partum haemorrhage and rendered a comparable ratio of valid umbilical artery blood gas samples. In paper III, the Ages and Stages Questionnaire was used to assess neurodevelopment at 4 months. The total scores did not differ, but the DCC group had a higher score in the problem-solving domain and a lower score in the personal-social domain. Immunoglobulin G level was 0.7 g/L higher in the DCC group at 2–3 days, but did not differ at 4 months. Symptoms of infection up to 4 months were comparable between groups. Finally, in paper IV, iron stores and neurodevelopment were similar between groups at 12 months. Gender specific outcome on neurodevelopment at 12 months was discovered, implying positive effects from DCC on boys and negative on girls. We conclude that delaying umbilical cord clamping for 180 seconds is safe and associated with a significantly reduced risk for iron deficiency at 4 months, which may have neurodevelopmental effects at a later age.

Background Due to small iron stores and rapid growth during the first months of life, infants with low birth weight (LBW) are at risk of iron deficiency (ID). ID in infancy is associated with irreversible impaired neurodevelopment. Preventive iron supplementation may reduce the risk of ID and benefit neurodevelopment, but there is also a possible risk of adverse effects. More than 50% of all LBW infants are born with marginally LBW (MLBW, 2000-2500g), and it is not known if they benefit from iron supplementation. Methods We randomized 285 healthy, Swedish, MLBW infants to receive 3 different doses of oral iron supplements; 0 (Placebo), 1, and 2 mg/kg/day from six weeks to six months of age. Iron status, during and after the intervention was assessed and so was the prevalence of ID and ID anemia (IDA), growth, morbidity and the interplay with iron and the erythropoetic hormones hepcidin and erythropoietin (EPO). As a proxy for conduction speed in the developing brain, auditory brainstem response (ABR) was analyzed at six months. In a follow up at 3.5 years of age, the children were assessed with a cognitive test (WPPSI-III) and a validated parental checklist of behavioral problems (CBCL), and compared to a matched reference group of 95 children born with normal birth weight. Results At six months of age, the prevalence of ID and IDA was significantly higher in the placebo group compared to the iron supplemented infants. 36% had ID in the placebo group, compared to 8% and 4 % in the 1 and 2mg/kg/day-groups, respectively. The prevalence of IDA was 10%, 3% and 0%, respectively. ABR-latencies did not correlate with the iron intake and was not increased in infants with ID or IDA. ABR wave V latencies were similar in all three groups. Hepcidin correlated to ferritin and increased in supplemented infants while EPO, which was negatively correlated to iron status indicators, decreased. At follow up there were no differences in cognitive scores between the groups but the prevalence of behavioral problems was significantly higher in the placebo group compared to those supplemented and to controls. The relative risk increase of CBCL-scores above a validated cutoff was 4.5 (1.4 – 14.2) in the placebo-group compared to supplemented children. There was no detected difference in growth or morbidity at any age. Conclusion MLBW infants are at risk of ID in infancy and behavioral problems at 3 years of age. Iron supplementation at a dose of 1-2 mg/kg/day from six weeks to six months of age reduces the risks with no adverse effects, suggesting both short and long term benefit. MLBW infants should be included in general iron supplementation programs during their first six months of life.

Les réseaux BAN (Body Area Network) révolutionnent le concept de la surveillance et de la prise en charge à distance de la santé du patient. Le BAN fournit des informations sur l'état de santé du patient en temps réel quelque soit l'endroit où il se trouve. Dans le « télé monitoring », des capteurs de mouvement, de respiration ou du rythme cardiaque placés à l'intérieur ou sur le corps humain transmettent des données via le réseau sans fil constituant le BAN, une antenne étant associée à chaque nœud du réseau. La communication peut être in/on, on/on ou on/off selon que les antennes sont placées à l'intérieur, sur ou à l'extérieur du corps. Le développement des BAN nécessite la réalisation de modèles (ou fantômes) simulant au mieux les propriétés électromagnétiques du corps humain. Des antennes portables, miniaturisées doivent être réalisées avec des contraintes d'intégration d'une part (aux vêtements, à des objets type montre ou badge), des contraintes de résistance ou de prise en compte de l'influence du corps d'autre part. La réduction de l'impact des antennes sur les tissus en terme de SAR (Specific Absorption Rate) doit également être considérée. Dans ce travail, l'objectif est de développer des fantômes valables pour les communications dans et sur le corps. Les matériaux de base sélectionnés sont d'origine biologique (biocéramiques et biopolymères) avec des propriétés proches de celles des tissus humains. Ces fantômes étant biocompatibles, ils sont essentiellement non toxiques alors que les fantômes usuels le sont en général. D'autre part, différents types d'antennes conformables, fonctionnant dans la bande ISM 2.4 GHz ont été développées et étudiées dans la perspective du BAN. Les antennes voient leur adaptation et leur efficacité chuter au contact ou à proximité du corps, ce qui constitue un écueil majeur pour établir une bonne communication. Différentes méthodes permettant de réduire l'influence du corps (plan de masse à l'arrière, surface haute impédance, feuille de ferrite polymère) sont testés et leurs avantages et inconvénients développés. Des mesures de SAR permettent aussi de démontrer l'efficacité de ces méthodes sur la réduction de la puissance absorbée par les tissus. Au final, ce travail apporte une contribution à l'étude théorique et expérimentale de l'interaction entre corps humain et antenne dans le cadre des réseaux BAN appliqués à la télésurveillance de la santé

Memoria para optar al Título Profesional de Médico Veterinario
La ferritina es una proteína que se encuentra en alimentos de origen animal y vegetal. Esta proteína tiene como función almacenar hasta 4.500 átomos de hierro en su interior como reserva. Se ha postulado que la ferritina tiene una vía de absorción intestinal propia. Sin embargo, en un estudio previo se demostró que el hierro ferritínico competía por la vía de absorción de Fe no-hemínico (Fe no-Hem) cuando era administrada en cápsulas de liberación gástrica. Objetivo: Determinar si el hierro ferritínico de origen animal compite por la vía de absorción del Fe no-Hem cuando es liberado a nivel duodenal. Sujetos y métodos: 30 mujeres, sanas de entre 35 a 45 años de edad, participaron en 2 protocolos de absorción. En el protocolo A se hizo competir 0,5 mg de Fe como ferritina marcada intrínsicamente con 55Fe ó 59Fe, con 0; 4,5; 9,5 y 49,5 mg de Fe como FeSO4. Los compuestos fueron administrados en cápsulas de liberación entérica. Por otra parte, es sabido que al ácido ascórbico (AA) es un fuerte favorecedor de la absorción de Fe no-Hem, por tanto en el protocolo B se probó si el AA mejoraba la absorción del Fe ferritínico (relación molar AA:Fe, 4:1). Estos compuestos fueron ingeridos tanto en cápsulas de liberación gástrica como entérica. En ambos protocolos, los días 1, 2, 14 y 15 fueron administrados los compuestos marcados con isótopos de Fe y en los días 14 y 28 se midió la radiactividad circulante para determinar la biodisponibilidad de hierro. Se estableció el estado de nutrición de hierro de los sujetos por mediciones de hemoglobina, VCM, Zn-protoporfirina, saturación de transferrina y ferritina sérica. Resultados: El promedio geométrico de biodisponibilidad del hierro ferritínico del protocolo A fue de 26,3; 22,1; 14,3 y 9,6% para dosis de competencia con Fe no-Hem de 0; 4,5; 9,5 y 49,5 mg respectivamente (ANDEVA para muestras repetidas, p<0,05). En el protocolo B, el promedio geométrico de biodisponibilidad de hierro ferritínico solo liberado gástricamente fue de 38,8% y al ser administrado junto con ácido ascórbico, el valor fue de 31,2% (tpar de Student, N.S.). La ferritina liberada entéricamente, presentó promedios geométricos de 32,5% cuando se ingirió sola y 43,3% cuando se administró junto a ácido ascórbico (tpar de Student, p<0,03). Conclusión: Los resultados de estos estudios sugieren que el hierro ferritínico es liberado a nivel duodenal, pasa a formar parte del pool común de hierro no hemínico, y por tanto estaría compitiendo por los transportadores del Fe no-Hem ubicados en el enterocito. Esto indicaría que el hierro ferritínico se absorbería por la vía del Fe no-Hem

This thesis dealt with the study of the human ferritins family, the main iron storage proteins. It focused on the development of efficient methods for the heterologous expression in E.coli of different types of human ferritins. These samples have been used for the study of iron pathways in ferritin via structural approaches and to unreveal novel features of this class of nanocage proteins. This work permitted the identification of the key residues in the catalytic ferroxidase site of H-type ferritin, and of the nucleation site of ferroxidase-inactive L-type ferritin. The design, production and functional characterization of a number of mutants allowed to validate the mechanistic hypotheses suggested by the structural data. Thanks to its endogenous origin and its peculiar nanocage structure, ferritin has been exploited as a nanocarrier for the delivery of contrast agents and/or drugs. Following this interest, a study of the interaction between ferritin and some drug molecules has been also discussed.

Human ferritin H-chain (HFt) nanoparticles represent one of the most appropriate vectors for cellular delivery of molecules thanks to their specific cell internalization by human Transferrin Receptor 1 (CD71), a transmembrane receptor overexpressed in most cancer cell types. In this PhD thesis I report the determination of the structure of HFt and CD71 in the form of complex, by using cryo electron microscopy (cryo-EM) technique. The two proteins have been shown to interact very tightly with nanomolar affinity, as assessed by Surface Plasmon Resonance (SPR) experiments. Our cryo-EM data unveil the residues involved in this contact and provide a sound structural basis to elaborate on the possibility of developing alternative ferritin-like anti-viral or anti-parasite therapeutic ligand, be it an antibody or a peptidomimetic capable of blocking the “common contacts” epitope on CD71 residue, and to further engineering ferritins as theranostic agents. In this thesis I also report the development and characterization, in vitro and in vivo, of two HFt-based nanovectors containing Mitoxantrone (MIT) or Genz-644282 as cancer drug payload, named HFt-MP-PASE-MIT or The-0504, respectively. The results reported here are very promising and pave the way for an effective cancer-targeted chemotherapy using our HFt-based nanovector platforms.

碩士
國立臺灣大學
農業化學研究所
91
Ferritin is a major protein involved in metabolism of ferrum and recognized as a nonspecific tumor marker. In this study, two murine anti-ferritin monoclonal antibody-producing hybridomas were obtained, and designated as A3B7G and A8F respectively. Isotype of the antibody A3B7G was identified as IgG2a heavy chain and k light chain. DEAE-650 ion exchange and Protein G columns were used to purify IgG. IgM was purified by Sephacryl S-200 gel filtration and IgM affinity purification columns. These antibodies were used to develop sandwich enzyme-linked immunosorbent assay （ELISA） to detect ferritin quantitatively. A8F antibody was used as a catcher on Nunc 96-well ELISA plates and A3B7G conjugated with horseradish peroxidase（HRP） was used as a detection antibody. Antibodies and HRP conjugated by sodium periodate revealed better detection than those conjugated by SMCC. Detection range of ferritin was from 30 to 1000 ng/mL, and r2=0.9968. The antibody---IgG was immobilized on the silver electrode of quartz chips by physical adsorption methods. When the concentration of the IgG was 0.5 mg/mL, we got the most adsorbed IgG on chips and the ΔF(Fab-F0)= 580 Hz. We found that when using the method to exam different concentrations of ferritin, the results were opposite to theoretical valves. So we concluded that IgG couldn’t be stably immobilized on quartz chips. Through making use of cystamine-glutaraldhyde and 3-Glycidoxypropyl-trimethoxysilane methods to immobilize antibodies on chips would let us get the maximum changed shaking frequencies. But the silver electrodes were easy to peel off from the chips after it is blocked.

碩士
東海大學
化學系
99
This studies has discussed to modify CdSe quantum dots (QDs) on screen-printed carbon electrodes, and conjugate to antibody detected glyphosate and human serum ferritin, developing a QDs electrochemiluminescence (ECL) biosensor. First a carbon Nanotube (CNT) and chitosan (CHIT) mixture coating on electrode surface, forming a CNT-CHIT thin film , then the surface modified thioglycolic acid (TGA) CdSe/TGA QDs is fixed in the thin film. use (3-Aminopropyl)triethoxysilane (APS) and N-succinimidyl-4-(maleimido- -methyl) cyclohexanecarboxylate (SMCC) to link antibody with the QDs on electrode surface. When antigen in sample solution reacted with antibody producing immunocomplex , will cause changed of the QDs surface state , result in ECL intensity decayed. This dissertation has two parts: The first part detects Gly by the QDs cajugated Gly antibody modified screen printing carbon electrode, examines the mensurable range is 0.01~20.0 ng/mL, the linear correlation coefficient (R2) 0.9906. The second part replace the screen printing carbon electrode surface QDs conjugated antibody by ferritin antibody. Detecting human serum ferritin mensurable range is 0.1~20.0 ng/mL, the linear correlation coefficient (R2) 0.9952, detection limit 0.07 ng/mL. Observes in the blood 5 kind of possibly influential species, including: The human serum albumin, Alpha-Fetoprotein, human hemoglobin, human transferrin, ferric chloride. The influence of those species are not serious of our method. To analyze in 10 volunteer blood serum's ferritin result compared with the ELISA method, under 95% confidence degree, those result has good Similarity. Demonstrated that the QDs ECL biosensor sensing ferritin has the high sensitivity, high accuracy, simultaneously cost not expensive, and may produce once a lot.