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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
511

Reproductive Biology of the Female Bottlenose Dolphin (Tursiops Truncatus)

Muraco, Holley Stone 11 December 2015 (has links)
The goal of this long-term study was to better understand the reproductive biology of the female bottlenose dolphin (Tursiops truncatus) and provide a hypothesis for how dolphins may communicate reproductive readiness to one another. Utilizing conditioned dolphins in aquaria, this dissertation examined several previously unknown aspects of dolphin reproduction, including ovarian follicular dynamics during the luteinizing hormone surge, urinary prolactin levels, estrus behavior, vaginal fluid arboriform arrangement, in-situ vaginal and cervical anatomy during estrus, reversed-phase high-performance liquid chromatography (RP-HPLC) of urine samples to identify proteins and peptides that may be used in chemical communication, and a review and anatomical analysis of dolphin vibrassal crypts. The diffusely seasonal dolphin estrous cycle is not controlled by photoperiod and has a 10-day follicular and 20-day luteal phase. A brief ovulatory LH surge is followed by ovulation within 48 hours. An ethogram of 20 reproductive behaviors was developed, and all occurrences of reproductive behavior were analyzed during conceptive estrous cycles. A novel form of standing heat estrus, termed immobility, was observed, and estrus dolphins displayed genital nuzzling, active and passive mounting with other females, and an increase of standing heat intensity as LH levels rose. Prolactin plays a role in pregnancy maintenance, mammary development, allo-mothering behavior, lactation, and lactational anestrus. Dolphins are similar to sows where weaning causes a return to estrus, and in the boar effect, where days to ovulation are shortened in the presence of a mature male. Dolphin vaginal fluid showed crystallization arrangements with large open mesh patterns, conducive to sperm transport, during the estrogenic follicular phase, and closed mesh during the luteal phase. RP-HPLC analysis revealed that urine contained large amounts of peptides and proteins with peaks that change throughout the estrous cycle and with changes in social grouping. Remnant vibrissae from dolphin follicular crypts were sectioned, and it was hypothesized that trigeminal nerve endings could act similarly to those found in the nasal mucosa of terrestrial species and respond to chemical stimuli. This study provides new data to better understand the reproductive biology of a holaquatic mammal.
512

Density and proximity of unconventional oil and gas wells and concentrations of trace elements in urine, hair, nails and tap water samples from pregnant women living in Northeastern British Columbia

Gasparyan, Lilit 07 1900 (has links)
The Peace River Valley (British Columbia, Canada) is an area of intensive unconventional oil and gas (UOG) exploitation, an activity that can release contaminants with possible adverse effects on the fetus. My project aimed to estimate the importance of this exposure. For this aim, we 1) measured concentrations of 21 trace elements in tap water and biological (hair, urine, nails) samples from 85 pregnant women in this region; 2) compared them with those from the general population and health-based guidance values; 3) assessed their correlations between matrices; and 4) evaluated their associations with the density and proximity of UOG wells (i.e., wells within radii of 2.5 km, 5 km, 10 km, and with all wells in British Columbia around residences). Spearman's rank correlation and multiple linear regression analyses adjusted covariates were performed. Our results showed higher urinary and hair levels of certain trace elements compared to reference populations (e.g., Co, Ba, Sr, Mn, V, Ga). Concentrations in tap water correlated strongest with concentrations in hair, followed by nails and urine. Positive (e.g., Al, Mn, Cu, Ga, Cd, Ba, Cr, Sr, U) and negative (e.g., Fe) associations were observed between the density and proximity of UOG wells and the concentrations of certain trace elements in tap water, hair, and nails. Our results suggest that pregnant women living in an active area of UOG exploitation are likely to be more exposed to certain trace elements than the general population, but the association with density and proximity to wells remains uncertain. / La vallée de la rivière de la Paix (Colombie-Britannique, Canada) est une zone d’exploitation de pétrole et de gaz naturel par méthodes non-conventionnelles (PGNNC), une activité qui est susceptible de libérer des contaminants avec des effets nocifs possibles sur le foetus. Mon projet visait à estimer l’importance de cette exposition. À cette fin, nous avons 1) mesuré les concentrations de 21 éléments traces dans des échantillons de cheveux, d'ongles, d'urine et d'eau du robinet de 85 femmes enceintes de cette région, 2) comparé celles-ci avec celles de la population générale et des valeurs-guides, 3) évalué leur corrélation entre matrices et 4) évalué leur association avec la densité et proximité des puits (mesures pour des rayons de 2,5 km, 5 km, 10 km, et sans limite autour des résidences). Des analyses de corrélation de Spearman et de régression linéaire multiple ajustées pour certaines variables ont été effectuées. Les concentrations urinaires et capillaires étaient plus élevées pour certains éléments traces par rapport aux populations de référence (p. ex. Co, Ba, Sr, Mn, V, Ga). Les concentrations dans l'eau du robinet étaient plus fortement corrélées avec les concentrations dans les cheveux, suivis des ongles et de l'urine. Des associations positives (p. ex. Al, Mn, Cu, Ga, Cd, Ba, Cr, Sr, U) et négatives (p. ex. Fe) ont été observées entre la densité/proximité des puits de PGNNC et les concentrations de certains éléments traces dans les échantillons d'eau, de cheveux et d’ongles. Nos résultats portent à croire que les femmes enceintes vivant dans une zone active de PGNNC sont susceptibles d’être plus exposées à certains éléments traces que la population générale, mais le lien avec la densité et la proximité des puits demeure incertain.
513

Élaboration d'une approche de biosurveillance humaine pour évaluer l'exposition aux métaux et éléments traces de la population libanaise et son association avec la consommation d'eau potable

Nasser Eddine, Nessrine 08 1900 (has links)
Dans le contexte libanais, les infrastructures de traitement et d’approvisionnement en eau potable ne sont pas optimales et il existe un manque de connaissances sur l’association entre la consommation d’eau et les niveaux d’exposition aux métaux et éléments traces. La présente étude est une première tentative faisant état de l'exposition aux métaux et aux éléments traces dans des sous-groupes de la population libanaise en utilisant une approche de biosurveillance multi-matrices. Les concentrations en 11 métaux et éléments traces (aluminium (Al), arsenic (As), cadmium (Cd), chrome (Cr), cuivre (Cu), fer (Fe), plomb (Pb), manganèse (Mn), sélénium (Se), uranium (U), zinc (Zn)) ont été mesurées dans des échantillons d'urine, de cheveux et d'ongles d’orteils d'un groupe de la population et les niveaux ont été comparés en fonction de l'âge, du sexe, du tabagisme, du statut économique, de la zone géographique et de la source d'eau potable. Alors que la plupart des concentrations urinaires et d'ongles n'étaient pas statistiquement différentes entre les hommes et les femmes, les concentrations mesurées d'éléments dans les cheveux étaient statistiquement plus élevées chez les femmes que chez les hommes. Les concentrations urinaires d'Al, Cu, Se et Zn étaient statistiquement plus élevées chez les enfants comparativement aux adolescents et aux adultes. Les concentrations de plusieurs éléments dans les cheveux et les ongles (As, Cd, Pb, Mn, Se dans les cheveux et les ongles plus Al, Fe dans les ongles d’orteils) étaient significativement plus élevées chez les enfants que chez les adolescents et/ou adultes (MG chez les enfants vs. les adolescents vs. les adultes dans les cheveux: 0,009 vs 0,009 vs. 0.005 µg As/g (p<0,01); 0,046 vs. 0,016 vs. 0,022 µg Cd/ g (p<0,05); 1,16 vs. 0,580 vs. 0,627 µg Pb/g (p<0,1); 0,305 vs. 0,168 vs. 0,275 µg Mn/g (p<0,1); 0,365 vs. 0,370 vs. 0,217 µg Se/g (p<0,05) et dans les ongles d’orteils : 17,0 vs. 14,3 vs. 7,31 µg Al/g et 56,9 vs. 46,0 vs. 23,8 µg Fe/g (p<0,05). Le statut tabagique n’a aucune influence sur les concentrations de As, cd et Pb. Les niveaux de Cd, Pb et Mn étaient également statistiquement plus élevés dans les échantillons des sous-groupes ayant un statut économique inférieur (Cd et Pb dans les 3 matrices urines, cheveux et ongles d’orteils respectivement de 0,223 µg Cd/L(p<0,1); 0,062 µg Cd/ g (p<0,05) et 0,038 µg Cd/ g (p<0,01); 1,16 µg Pb/L(p<0,05); 1,84 µg Pb/ g (p<0,01) et 0,840 µg Pb/ g (p<0,01) et Mn dans les cheveux et ongles d’orteils respectivement de 0,434 µg Mn/ g (p<0,05); 0,689 µg Mn/g (p<0,05). Les mêmes tendances ont été observées pour la stratification en fonction de la zone géographique, mais la différence n'était pas statistiquement significative, sauf pour le Pb dans l'urine où les participants de Beyrouth centre avaient des niveaux urinaires significativement moins élevés que les autres zones (0,560 µg Pb/L(p<0,01). Très peu de corrélations ont été identifiées entre les sources d’eau potable et les concentrations des métaux et éléments traces dans les urines, cheveux et ongles d’orteils. Cependant, une corrélation a été trouvée entre les niveaux d’As, Cd et Pb dans les cheveux et les ongles d’orteils respectivement (r = 0,4, p<0,05); (r = 0,310, p<0,05) et (r = 0.,270, p<0,1). Dans l’ensemble, les résultats ont montré que la population était exposée à des concentrations plus élevées de certains métaux que les autres populations, une attention particulière doit être accordée à l'exposition aux As, Cd et Pb, Mn et Se. Bien que la source d'eau n'ait pas contribué à la différence dans les niveaux d'exposition, les niveaux de certains métaux et éléments traces différaient selon l'âge, le sexe, les zones géographiques de résidence et le statut économique. Il pourrait être pertinent d'étendre ce type d'enquête à une initiative de biosurveillance humaine à grande échelle dans la population libanaise afin de valider et de généraliser les résultats et d'observer les tendances temporelles dans le temps. / In the Lebanese context, drinking water treatment and supply infrastructures are not optimal and it exists a lack of knowledge on the association between water consumption and levels of exposure to metals and trace elements. The present study is a first attempt reporting exposure to metals and trace elements in subgroups of the Lebanese population using a multi-matrix biomonitoring approach. Concentrations of 11 metals and trace elements (aluminum (Al), arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), lead (Pb), manganese (Mn), selenium (Se), uranium (U), zinc (Zn)) were measured in urine, hair and toenail samples from a population group and the levels were compared according to the age, gender, smoking status, economic status, geographic area, and source of drinking water. While most urinary and nail concentrations were not statistically different between men and women, measured element concentrations in hair were statistically higher in women than in men. Urinary concentrations of Al, Cu, Se and Zn were statistically higher in children compared to adolescents and adults. Concentrations of several elements in hair and nails (As, Cd, Pb, Mn, Se in hair and toenails plus Al, Fe in toenails) were significantly higher in children than in adolescents and/or adults (MG in children vs. adolescents vs. adults in hair: 0.009 vs. 0.009 vs. 0.005 µg As/g (p<0.01); 0.046 vs. 0.016 vs. 0.022 µg Cd/g (p< 0.05), 1.16 vs. 0.580 vs. 0.627 µg Pb/g (p<0.1), 0.305 vs. 0.168 vs. 0.275 µg Mn/g (p<0.1), 0.365 vs. 0.370 vs. 0.217 µg Se/g (p<0.05) and in the nails: 17.0 vs. 14.3 vs. 7.31 µg Al/g and 56.9 vs. 46.0 vs. 23.8 µg Fe/g. Smoking status has no influence on the concentrations of metals and trace elements. The levels of Cd, Pb and Mn were also statistically higher in the samples of the subgroups with a lower economic status (Cd and Pb in the 3 matrices urine, hair and toenails respectively of 0.223 µg Cd/L (p<0, 1);0.062 µg Cd/g (p<0.05) and 0.038 µg Cd/g (p<0.01);1.16 µg Pb/L(p<0.05);1.84 µg Pb/ g (p<0.01) and 0.840 µg Pb/g (p<0.01) and Mn in hair and toenails respectively 0.434 µg Mn/g (p<0.05), 0.689 µg Mn/g (p <0.05). The same trends were observed for stratification according to geographical area, but the difference was not statistically significant, except for Pb in urine where participants from central Beirut had significantly lower urinary levels than the others zones (0.560 µg Pb/L (p<0.01). Very few correlations have been identified between the sources of drinking water and the concentrations of metals and trace elements in urine, hair and toenails. However, a correlation was found between As, Cd and Pb levels in hair and toenails respectively r = 0.4, p<0.05), r = 0.310, p<0.05) and r = 0.270, p<0.1). Overall, the results showed that the population was exposed to higher concentrations of some metals than other populations, particular attention should be paid to exposure to As, Cd and Pb, Mn and Se. Although water source did not contribute to the difference in exposure levels, levels of some metals and trace elements differed by age, sex, smoking status, geographic areas of residence, and economic status. It might be relevant to extend this type of investigation to a large-scale human biomonitoring initiative in the Lebanese population in order to validate and generalize the results and to observe temporal trends over time.
514

Metabolomic Assessment of Dietary Interventions in Obesity by Capillary Electrophoresis Mass Spectrometry

Lam, Karen Phoebe January 2018 (has links)
Capillary electrophoresis mass spectrometry (CE-MS) is a versatile instrumental method for metabolomics, which allows for comprehensive metabolite profiling of volume-limited biological specimens in order to better understand the molecular mechanisms associated with chronic diseases, including an alarming epidemic of obesity worldwide. Multiplexed CE separations enable high-throughput metabolite screening with quality assurance to prevent false discoveries when combined with rigorous method validation, robust experimental designs, complementary statistical methods, and high-resolution tandem mass spectrometry (MS/MS) for unknown metabolite identification. In this thesis, multiplexed CE-MS technology is applied for both targeted and untargeted metabolite profiling of various biological fluids, including covalently bound thiol-protein conjugates, as well as free circulating metabolites in serum and plasma, and excreted/bio-transformed compounds in urine due to complex host-gut microflora co-metabolism. This work was applied to characterize aberrant metabolic responses of obese subjects in response to dietary challenges, and measure the benefits of dietary interventions that reduce adiposity without deleterious muscle loss. Chapter 2 presents, a simple, sensitive yet robust analytical protocol to expand metabolome coverage in CE-MS for the discovery of labile protein thiols in human plasma using a rapid chemical derivatization method based on N-tert-butylmaleimide (NTBM). Chapter 3 describes targeted metabolite profiling of serum and plasma to investigate the differential metabolic responses between healthy and unhealthy obese individuals before and after consumption of a standardized high-caloric meal, respectively. Chapter 4 of this thesis describes an untargeted metabolite profiling strategy for urine using multisegment-injection (MSI)-CE-MS for elucidating the effects of protein supplementation following a short-term dietary weight-loss intervention study. This work revealed six urinary metabolites that were classified as top-ranking treatment response biomarkers useful for discriminating between subjects consuming carbohydrate (control), soy, and whey supplemented diets. In summary, this thesis demonstrated the successful implementation of multiplexed CE-MS technology for biomarker discovery in nutritional-based metabolomic studies as required for more effective treatment and prevention of obesity for innovations in public health. / Thesis / Doctor of Philosophy (PhD)
515

TARGETED AND NON-TARGETED METABOLITE ANALYSIS FOR DISEASE RISK ASSESSMENT: MEASURING BIOMARKERS OF SMOKE EXPOSURE AND HABITUAL DIET

Wellington, Nadine L January 2019 (has links)
Exposomics applies metabolomics methods and technologies to the comprehensive analysis of all low molecular weight molecules (< 1.5 kDa) in complex biological samples to characterize the interaction between cellular metabolism and exogenous lifestyle exposures that determine health and quality of life. To fully access the diverse classes of biological molecules related to an individual’s metabolic profile, metabolomics frequently requires the use of complementary analytical platforms, and employs targeted and untargeted molecular profiling strategies to identify biomarkers that are clinically relevant to an individual’s health status. Chapter 2 describes a quinoline-based boronic acid biosensor for N-acetylneuraminic acid that undergoes a striking binding enhancement under strongly acidic conditions. For the first time, this work allows for direct analysis of acidic sugars with high selectivity when using UV absorbance or fluorescence detection based on formation of a highly stable boronate ester complex with metabolites containing an α-hydroxycarboxylate moiety. Chapter 3 describes a targeted analysis of 24 different organic contaminants using GC-MS that can serve as biomarkers of recent smoke exposure following search-and-rescue training exercises by firefighters located at three different sites across the province of Ontario. Importantly, skin and possible respiratory uptake of various polycyclic aromatic hydrocarbons, methoxyphenols, and resin acids was confirmed by peak excretion of several wood smoke biomarkers in urine within 6 h following acute exposure. Chapter 4 applied a cross-platform metabolomics strategy based on CE-MS and GC-MS in order to identify and validate dietary biomarkers in matching plasma and urine samples collected from healthy participants in the pilot Diet and Gene Interaction Study (DIGEST). For the first time, we demonstrate that a panel of metabolites can serve as reliable biomarkers following contrasting Prudent and Western diets over 2 weeks of food provisions, which correlated well with self-reported diet records. This work paves the way for the development of objective biomarkers for accurate assessment of wood smoke exposures, as well as complex dietary patterns as required for new advances in occupational health and nutritional epidemiology. / Dissertation / Doctor of Philosophy (PhD) / Exposomics is an emerging multidisciplinary science aimed at deciphering the complex interactions that impact human health and gene expression, such as lifestyle choices (i.e., habitual diet) and lifelong environmental exposures. There is growing interest in identifying biomarkers that can be readily measured for chronic disease prevention given an alarming global prevalence of obesity and cardiometabolic disorders, including heart disease, type 2 diabetes and cancer. The research in this thesis focuses on developing new analytical methods for identifying and quantifying metabolites that may allow for better assessments of human health, and has contributed to the development of novel biosensors for the targeted analysis of N-acetylneuraminic (sialic) acid and related acidic sugars, as well as high resolution methods for broad spectrum analysis of biotransformed organic contaminants from smoke exposure by GC-MS, and plasma and urinary metabolites that differentiate contrasting Prudent and Western diets and correlate well with self-reported diet records.
516

Studies on the Reaction of Dietary Methylglyoxal and Creatine during Simulated Gastrointestinal Digestion and in Human Volunteers

Treibmann, Stephanie, Groß, Julia, Pätzold, Susann, Henle, Thomas 18 April 2024 (has links)
The reactive 1,2-dicarbonyl compound methylglyoxal (MGO) is consumed with food and its concentrations decrease during digestion. In the present paper, the reaction of MGO with creatine, arginine, and lysine during simulated digestion, and its reaction with creatine during the digestion in human volunteers, was studied. Therefore, simulated digestion experiments with a gastric and an intestinal phase were performed. Additionally, an intervention study with 12 subjects consuming MGO-containing Manuka honey and creatine simultaneously or separately was conducted. Derivatization with o-phenylenediamine and HPLC–UV was used to measure MGO, while creatine and glycated amino compounds were analyzed via HPLC–MS/MS. We show that MGO quickly reacts with creatine and arginine, but not lysine, during simulated digestion. Creatine reacts with 56% of MGO to form the hydroimidazolone MG-HCr, and arginine reacted with 4% of MGO to form the hydroimidazolone MG-H1. In the intervention study, urinary MG-HCr excretion is higher in subjects who consumed MGO and creatine simultaneously compared to subjects who ingested the substances separately. This demonstrates that the 1,2-dicarbonyl compound MGO reacts with amino compounds during human digestion, and glycated adducts are formed. These contribute to dietary glycation products consumed, and should be considered in studies investigating their physiological consequences.
517

Cigarette smoke-induced transgenerational alterations in genome stability in cord blood of human F1 offspring

Laubenthal, Julian, Zlobinskaya, O., Poterlowicz, Krzysztof, Baumgartner, Adolf, Gdula, Michal R., Fthenou, E., Keramarou, M., Hepworth, S.J., Kleinjans, J.C., van Schooten, F.J., Brunborg, G., Godschalk, R.W., Schmid, Thomas E., Anderson, Diana January 2012 (has links)
No / The relevance of preconceptional and prenatal toxicant exposures for genomic stability in offspring is difficult to analyze in human populations, because gestational exposures usually cannot be separated from preconceptional exposures. To analyze the roles of exposures during gestation and conception on genomic stability in the offspring, stability was assessed via the Comet assay and highly sensitive, semiautomated confocal laser scans of gammaH2AX foci in cord, maternal, and paternal blood as well as spermatozoa from 39 families in Crete, Greece, and the United Kingdom. With use of multivariate linear regression analysis with backward selection, preconceptional paternal smoking (% tail DNA: P>0.032; gammaH2AX foci: P>0.018) and gestational maternal (% tail DNA: P>0.033) smoking were found to statistically significantly predict DNA damage in the cord blood of F1 offspring. Maternal passive smoke exposure was not identified as a predictor of DNA damage in cord blood, indicating that the effect of paternal smoking may be transmitted via the spermatozoal genome. Taken together, these studies reveal a role for cigarette smoke in the induction of DNA alterations in human F1 offspring via exposures of the fetus in utero or the paternal germline. Moreover, the identification of transgenerational DNA alterations in the unexposed F1 offspring of smoking-exposed fathers supports the claim that cigarette smoke is a human germ cell mutagen.
518

Novel Diagnostic and Prognostic Methods for Cancer and Cancer Associated Thrombosis

Oto Martínez, Ana Julia 02 August 2023 (has links)
Tesis por compendio / [ES] El cáncer constituye la segunda causa de muerte en España. El tromboembolismo venoso (TEV), una complicación del cáncer, conlleva gran gasto del presupuesto sanitario y representa la segunda causa de muerte en estos pacientes. Sin embargo, las herramientas actuales disponibles para la identificación de pacientes oncológicos con elevado riesgo trombótico son limitadas. Adicionalmente, no existen métodos simples, mínimamente invasivos y económicos de diagnóstico de cáncer vesical. Por este motivo, se utilizan técnicas dañinas como la tomografía computarizada la cual implica una elevada dosis de exposición a radiación y procedimientos invasivos como la cistoscopia. Además, un estado hipercoagulable parece tener una relación directa con una mayor carga tumoral y un peor pronóstico. El objetivo principal de la presente Tesis Doctoral es explorar la utilidad clínica de nuevos métodos diagnósticos y pronósticos para el cáncer y sus complicaciones trombóticas. En la primera parte de la Tesis, nos hemos centrado en el papel de miRNAs en orina como biomarcadores de cáncer vesical. Hemos identificado al miR-29c-3p como el miRNA más estable por lo que fue utilizado como normalizador. Hemos ajustado un modelo de regresión logística ordinal para el diagnóstico y estratificación de cáncer vesical utilizando la expresión de miRNAs en orina de pacientes y controles. Este modelo incluyó la expresión de 7 miRNAs: miR-221-3p, miR-93-5p, miR-362-3p, miR-191-5p, miR-200c-3p, miR-192-5p y miR-21-5p. En la segunda parte de la Tesis, nos centramos en el estudio de nuevos biomarcadores para la trombosis asociada a cáncer. Analizamos el potencial predictivo de los miRNAs y de marcadores de activación de neutrófilos en pacientes con cáncer pancreático y pacientes con glioma y meningioma. En cáncer pancreático, obtuvimos un perfil de 7 miRNAs (miR-486-5p, miR-106b-5p, let-7i-5p, let-7g-5p, miR-144-3p, miR-19a-3p y miR-103a-3p) capaz de estimar el riesgo de TEV al diagnóstico con dianas incluidas en las rutas pancreatic cancer y complement and coagulation cascades. En el estudio de los marcadores de activación de neutrófilos, obtuvimos un nuevo modelo predictivo de TEV con la calprotectina como variable predictora. Respecto al estudio de trombosis asociada a cáncer en tumores intracraneales, en pacientes con glioma, ajustamos y validamos un modelo predictivo de embolismo pulmonar (EP) postquirúrgico con 6 miRNAs: miR-363-3p, miR-93-3p, miR-22-5p, miR-451a, miR-222-3p y miR-140-3p y otro con cfDNA y mieloperoxidasa como predictores. Además, hemos combinado los dos tipos de marcadores y hemos obtenido un modelo con mayor capacidad predictiva que incluye a miR-140-3p y a la mieloperoxidasa como predictores. En pacientes con meningioma, ajustamos y validamos un modelo predictivo de EP postquirúrgico con 6 miRNAs: miR-29a-3p, miR-660-5p, miR-331-3p, miR-126-5p, miR-23a-3p y miR-23b-3p. En conclusión, proponemos diferentes perfiles de biomarcadores para el diagnóstico de cáncer de vejiga y para la identificación de pacientes oncológicos con elevado riesgo de trombosis. / [CA] El càncer constitueix la segona causa de mort a Espanya. El tromboembolisme venós (TEV), una complicació del càncer, representa la segona causa de mort en aquests pacients i comporta una gran despesa sanitària. No obstant això, les eines disponibles actualment per a la identificació de pacients oncològics amb elevat risc trombòtic són limitades. Actualment, no existeixen mètodes diagnòstics per al càncer de bufeta senzills, mínimament invasius i econòmics. Per aquest motiu, s'utilitzen tècniques nocives com la tomografia computada la qual implica una elevada dosi d'exposició a radiació i procediments invasius com la cistoscòpia. A més, un estat hipercoagulable sembla tindre una relació directa amb una major càrrega tumoral i un pitjor pronòstic. L'objectiu principal de la present Tesi Doctoral fou explorar la utilitat clínica de nous mètodes diagnòstics i pronòstics per al càncer i les seues complicacions trombòtiques. En la primera part de la Tesi, ens hem centrat en el paper dels microRNAs (miRNAs) en orina com biomarcadors de càncer de bufeta. Hem identificat al miR-29c-3p com el miRNA més estable per la qual cosa va ser utilitzat com a normalitzador. Hem ajustat un model de regressió logística ordinal per al diagnòstic i estratificació de càncer de bufeta utilitzant l'expressió de miRNAs en orina de pacients i controls. Aquest model va incloure l'expressió de 7 miRNAs: miR-221-3p, miR-93-5p, miR-362-3p, miR-191-5p, miR-200c-3p, miR-192-5p i miR-21-5p. En la segona part de la Tesi, ens centràrem en l'estudi de nous biomarcadors per a la trombosi associada a càncer. Analitzàrem el potencial predictiu dels miRNAs i de marcadors d'activació de neutròfils en pacients amb càncer pancreàtic i pacients amb glioma i meningioma. En càncer pancreàtic, vàrem obtindre un perfil de 7 miRNAs (miR-486-5p, miR-106b-5p, let-7i-5p, let-7g-5p, miR-144-3p, miR-19a-3p i miR-103a-3p) capaç d'estimar el risc de TEV al diagnostic dels pacients els quals tenen dianes incloses en les rutes biològiques pancreatic cancer y complement and coagulation cascades. En el estudi dels marcadors d¿activació de neutròfils, vàrem obtenir un altre model predictiu de TEV amb la calprotectina com a variable predictora. Respecte a l'estudi de trombosi associada a càncer en tumors intracranials, en pacients amb glioma, ajustàrem i validàrem un model predictiu d'embolisme pulmonar (EP) incidental postquirúrgic amb 6 miRNAs (miR-363-3p, miR-93-3p, miR-22-5p, miR-451a, miR-222-3p i miR-140-3p) i un altre amb cfDNA i mieloperoxidasa com a predictors. A més, vàrem combinar els dos tipus de marcadors i vàrem obtenir un model amb major capacitat predictiva que inclou al miR-140-3p i la mieloperoxidasa com a predictors. En pacients amb meningioma, ajustàrem i validàrem un model predictiu d¿EP incidental postquirúrgic amb 6 miRNAs: miR-29a-3p, miR-660-5p, miR-331-3p, miR-126-5p, miR-23a-3p i miR-23b-3p. En conclusió, proposem diferents perfils de biomarcadors per al diagnòstic de càncer de bufeta i per a la identificació de pacients oncològics amb elevat risc de trombosi. / [EN] Cancer is the second leading cause of death in Spain. Collaterally, venous thromboembolism (VTE), as a complication of cancer, consumes a great part of its healthcare budget and, more importantly, it is the second cause of death in these patients. However, limited tools are available to identify high risk patients. Additionally, a simple, minimally invasive and economical diagnostic methods for bladder cancer are also lacking. For that aim, harmful techniques are used like CT scan with high radiation exposure and invasive procedures like cystoscopy. Moreover, a hypercoagulable state seems directly related to a large tumor burden and poor prognosis. The overall aim of this Doctoral Thesis is to explore the clinical utility of novel diagnostic and prognostic methods for cancer and its thrombotic complications. In the first part of this Doctoral Thesis, we focused on the role of urine miRNAs as bladder cancer biomarkers. We identified miR-29c-3p as the most stable miRNA and was therefore used as normalizer. We adjusted an ordinal logistic regression model for the diagnosis and stratification of BC using the urine miRNA expression levels of patients and controls. This model included 7 miRNAs: miR-221-3p, miR-93-5p, miR-362-3p, miR-191-5p, miR-200c-3p, miR-192-5p and miR-21-5p. In the second part of this Doctoral Thesis, we focused on the study of novel biomarkers for cancer-associated thrombosis. We analyzed the predictive potential of miRNAs and neutrophil activation markers of thrombotic events in patients with pancreatic cancer and patients with glioma and meningioma. In pancreatic cancer, we obtained a profile of 7 miRNAs (miR-486-5p, miR-106b-5p, let-7i-5p, let-7g-5p, miR-144-3p, miR-19a-3p and miR-103a-3p) able to estimate the risk of potential VTE at diagnosis with targets involved in the pancreatic cancer and complement and coagulation cascades pathways. In the study of the neutrophil activation makers, we obtained a new predictive model of VTE with calprotectin as predictor. Regarding the study of cancer-associated thrombosis in intracranial tumors, in glioma patients, we adjusted and validated a predictive model for post-surgical pulmonary embolism (PE) with 6 miRNAs: miR-363-3p, miR-93-3p, miR-22-5p, miR-451a, miR-222-3p and miR-140-3p, and another with cfDNA and myeloperoxidase as predictors. Furthermore, we combined both types of biomarkers and obtained an improved model using myeloperoxidase and miR-140-3p as predictors. In meningioma patients we fitted and validated a predictive model with 6 miRNAs: miR-29a-3p, miR-660-5p, miR-331-3p, miR-126-5p, miR-23a-3p and miR-23b-3p. In conclusion, we propose several profiles of biomarkers for the diagnosis of bladder cancer and for the identification of oncologic patients at high risk of suffering a thrombotic event. / Oto Martínez, AJ. (2022). Novel Diagnostic and Prognostic Methods for Cancer and Cancer Associated Thrombosis [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/181510 / Compendio
519

Modeling and causal inference methods for analyzing and transporting an environmental mixture effect

Mayer, Melanie Nicole January 2024 (has links)
An environmental mixture is composed of multiple environmental exposures. Quantifying this joint effect on health outcomes mirrors what occurs in nature, offering significant benefits to environmental epidemiological research. However, analyzing the impact of an environmental mixture poses numerous statistical and inferential challenges. Motivated by the Strong Heart Study (SHS), a prospective cohort study of cardiovascular disease (CVD) outcomes among three American Indian communities where urine samples were collected at three visits and analyzed for concentrations of various metal exposures, this dissertation aims to improve our ability to analyze the effect of multiple, continuous, and correlated exposures with complex relationships on a health outcome using observational study data, such as the metal mixture exposure in the SHS. The contributions of this dissertation address two challenges inherent in environmental mixture analyses: modeling methods and the transportability of estimated effects. In the first project presented in this dissertation, our goal was to evaluate the performance of available modeling methods for estimating the impact of an environmental mixture on survival outcomes. While survival time outcomes (also known as time-to-event outcomes) are very common in epidemiological studies, little attention has been given to examining the performance of existing modeling methods when estimating the effect of an environmental mixture on a survival outcome. In this chapter, we identified applicable and readily available modeling methods, assessed their performance through simulations replicating various real-world scenarios, and applied the selected methods to estimate the effect of a metal mixture on CVD incidence in the SHS. We examined proportional hazards (PH) based models as well as more flexible, machine learning-style models. Our simulations found that, when the PH assumption held, the effect estimates via flexible models had higher bias and variance compared to PH methods. However, when the PH assumption was violated, this discrepancy between the methods decreased and the more flexible methods achieved higher coverage. These simulation findings underscore the importance of demonstrating the robustness of findings across various modeling approaches in environmental epidemiology. In the SHS analysis, all methods found a significant, harmful effect of the metal mixture on incident CVD. However, the more flexible approaches found larger point estimates with wider confidence bands. The second and third projects of this dissertation focus on constructing a framework for transporting an environmental mixture effect across populations. Numerous methods exist for analyzing environmental mixture effects within a population where sample data is available for. However, being able to adjust these effects based on the exposure/covariate distribution of a different target population would enable more precise estimation of the mixture effect in that population. This, in turn, allows for more accurate estimation of effects for populations distinct from those sampled. This broadens available data sources and provides significant advantages to researchers and policymakers interested in specific populations. The second project leverages causal inference concepts to formally extend the transportability literature to the environmental mixtures context. We defined a relevant intervention with favorable properties concerning the exposure concentration positivity assumption and explicitly outline the assumptions needed to transport its effect across two observational studies. To assess whether the target population is well represented in the study population sample, which is required for the positivity of population membership assumption, a matching algorithm is proposed. Subject's environmental mixture exposure profiles are incorporated into subject matching on exposures and covariates between the two populations. Simulation results demonstrate that the matching algorithm effectively detects non-overlap across populations, with well-overlapped populations yielding minimally biased transported effect estimates, while those with insufficient overlap exhibit greater bias. Applying this framework, we estimated the effects of a metal mixture on coronary artery calcification (CAC) in the SHS cohort by transporting the effects observed in the Multi-Ethnic Study of Atherosclerosis (MESA). Although CAC was not directly measured in the SHS, its importance as a subclinical indicator of advanced atherosclerosis and its link to elevated cardiovascular risk underscore the significance of exploring its relationship with metal exposures in the SHS. Despite larger effects observed in the MESA population, significant effects persisted within the SHS, providing insights for innovative strategies in preventing and treating atherosclerosis progression among American Indian populations. In the third project, we turned our focus to violations of internal and external validity exchangeability assumptions. We proposed the use of a negative control exposure analysis modeled with Bayesian Kernel Machine Regression with hierarchical variable selection to identify unmeasured confounding in the context of multiple, continuous, and correlated exposures when exposures are measured at various time points. Additionally, we developed a novel method for detecting violations of transportability assumptions by assessing the transportability of an effect within a study population. If the internal validity assumptions are plausible, then the inability to transport an effect within a study population suggests the presence of unmeasured effect modification in the study sample. Through simulations, we demonstrated the efficacy of these methods in detecting unmeasured confounding and effect modification. We applied these methods to assess the robustness of the estimated effect of a metal mixture on fasting blood glucose levels in the SHS to violations of transportability assumptions and found evidence of both unmeasured confounding and effect modification. However, the internal effect estimate remained significant and robust to unmeasured confounding.
520

Development of Smart Devices for the Detection of Metabolites of Toxic Substances and Disease-Related Enzyme Overexpression

Domínguez Rodríguez, Marcia 18 January 2024 (has links)
Tesis por compendio / [ES] Esta tesis se enfoca en el desarrollo de dispositivos inteligentes para detectar metabolitos de sustancias tóxicas y la sobreexpresión enzimática relacionada con enfermedades. Se aborda la limitación de las técnicas de diagnóstico convencionales y se destaca la utilidad de la orina como muestra biológica. Se discuten conceptos de materiales mesoporosos de sílice, reconocimiento molecular y sondas moleculares fluorogénicas. Los objetivos se detallan, y luego se presenta un nanodispositivo para detectar ácido trans,trans-mucónico (t,t-MA) en orina (S4). Se describe una sonda fluorogénica en el infrarrojo cercano para la detección de elevados niveles de alanina aminopeptidasa en orina (NB-ALA). También se presentan nuevas sondas para detectar biomarcadores de cáncer (NB-SO3-Leu y NB-SO3-Ala), resaltando la importancia de su solubilidad y eliminación renal. Finalmente, se propone una sonda molecular no invasiva (Cy7-MAO) para detectar la enzima monoamina oxidasa a través de medidas de fluorescencia en la orina. Las conclusiones subrayan el potencial de estos sistemas para el diagnóstico y tratamiento de enfermedades. / [CA] Aquesta tesi s'enfoca en el desenvolupament de dispositius intel·ligents per detectar metabòlits de substàncies tòxiques i la sobreexpressió enzimàtica relacionada amb malalties. S'aborda la limitació de les tècniques de diagnòstic convencionals i destaca la utilitat de l'orina com a mostra biològica. Es discuteixen conceptes de materials mesoporosos de sílice, reconeixement molecular i sondes moleculars fluorogèniques. Els objectius es detallen, i després es presenta un nanodispositiu per detectar àcid trans, transmucònic (t, t-MA) en orina (S4). Es descriu una sonda fluorogènica a l'infraroig proper per a la detecció d'elevats nivells d'alanina aminopeptidasa en orina (NB-ALA). També es presenten noves sondes per detectar biomarcadors de càncer (NB-SO3-Leu i NB-SO3-Ala), ressaltant la importància de la seva solubilitat i eliminació renal. Finalment, es proposa una sonda molecular no invasiva (Cy7-MAO) per detectar l'enzim monoamina oxidasa a través de mesures de fluorescència a l'orina. Les conclusions subratllen el potencial d'aquests sistemes per al diagnòstic i el tractament de malalties. / [EN] This PhD thesis focuses on the development of smart devices for detecting metabolites of toxic substances and enzyme overexpression related to diseases. It addresses the limitations of conventional diagnostic techniques and highlights the usefulness of urine as a biological sample. Concepts of mesoporous silica materials, molecular recognition, and fluorogenic molecular probes are discussed. The objectives are outlined, and then a nanodevice for detecting trans, trans-muconic acid (t,t-MA) in urine (S4) is presented. A near-infrared fluorogenic probe for the detection of high levels of alanine aminopeptidase in urine (NB-ALA) is described. New probes for detecting cancer biomarkers (NB-SO3-Leu and NB-SO3-Ala) are also introduced, emphasizing the importance of their solubility and renal elimination. Finally, a non-invasive molecular probe (Cy7-MAO) is proposed for detecting monoamine oxidase enzyme through fluorescence measurements in urine. The conclusions underscore the potential of these systems for the diagnosis and treatment of diseases. / Domínguez Rodríguez, M. (2023). Development of Smart Devices for the Detection of Metabolites of Toxic Substances and Disease-Related Enzyme Overexpression [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/202015 / Compendio

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