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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.
471

Modelización matemática de la fragilidad valorada mediante el Índice Frágil-VIG y el SPPB, de la dependencia para las actividades básicas de la vida diaria y de la mortalidad en población general de 70 años o más. Validación del Índice Frágil-VIG respecto al SPPB.

Camacho Torregrosa, Susana 01 July 2024 (has links)
[ES] El envejecimiento poblacional y su progresión, es un hecho que debe ser abordado para el bienestar sanitario y social futuro, especialmente de las personas mayores, y por extensión, de toda la sociedad. En este sentido, la fragilidad, entendida como el declive progresivo en los sistemas fisiológicos relacionados con la edad, juega un papel clave. El estudio de la fragilidad mediante el Índice Frágil-VIG, permite abordar a los pacientes en la práctica clínica de una manera multidimensional, estableciendo un diagnóstico situacional. La presente tesis se compone de dos partes diferenciadas. Se realiza un análisis no paramétrico mediante el método Kaplan-Meier de las variables sociodemográficas y clínicas, para determinar los factores pronósticos de fragilidad según el Índice Frágil-VIG, de fragilidad según el Short Physical Performance Battery, de dependencia para las actividades básicas de la vida diaria, y de mortalidad. Posteriormente se procede a realizar análisis multivariantes mediante el modelo de regresión de Cox. Para el desarrollo de los modelos, se sigue la estrategia sugerida por Collett. Previamente, se realiza la validación del Índice Frágil-VIG respecto al Short Physical Performance Battery. Respecto al análisis no paramétrico, fueron factores pronósticos de fragilidad según el Índice Frágil-VIG el estado civil, el nivel de cronicidad y el número de convivientes; factores pronósticos de fragilidad según el Short Physical Performance Battery el nivel de cronicidad y el Índice Frágil-VIG; factores pronósticos de dependencia para las actividades básicas de la vida diaria el estado civil, la fragilidad según el Índice Frágil-VIG y el nivel de cronicidad; y factores pronósticos de mortalidad fueron la dependencia para las actividades básicas de la vida diaria, la fragilidad según el Índice Frágil-VIG, el nivel de estudios, el estado civil, el nivel de cronicidad y el sexo. En el análisis multivariante, las variables incluidas en los modelos de fragilidad según el Índice Frágil-VIG y la dependencia para las actividades básicas de la vida diaria, fueron el estado civil, el nivel de cronicidad y el sexo. En el modelo multivariante de fragilidad según el Short Physical Performance Battery fueron significativas las variables nivel de cronicidad y el número de convivientes. Y finalmente, en el modelo multivariante de mortalidad, resultaron significativas las variables nivel de estudios, el sexo y la fragilidad según el Índice Frágil-VIG. El Índice Frágil-VIG presentó una adecuada validez convergente y discriminativa respecto al Short Physical Performance Battery. Un 20% de las personas difirieron en el diagnóstico de fragilidad entre ambas herramientas, presentando perfiles diferentes. La validación del Índice Frágil-VIG ha fortalecido el uso del mismo para el desarrollo de los modelos. Los grupos de riesgo desarrollados pueden ayudar a establecer estrategias de salud diferenciadas, tanto a nivel individual en la consulta como a nivel poblacional. Con el objetivo de facilitar su implementación en la práctica clínica diaria, se han desarrollado nomogramas que permiten visualizar fácilmente con el objetivo de poder disponer de manera gráfica una herramienta aplicable en la consulta. / [CA] L'envelliment poblacional i la seua progressió, és un fet que ha de ser abordat per al benestar sanitari i social futur, especialment de les persones majors, i per extensió, de tota la societat. En este sentit, la fragilitat, entesa com el declivi progressiu en els sistemes fisiològics relacionats amb l'edat, juga un paper clau. L'estudi de la fragilitat mitjançant l'Índex Fràgil-VIG, permet abordar als pacients en la pràctica clínica d'una manera multidimensional, establint un diagnòstic situacional. La present tesi es compon de dues parts diferenciades. Es realitza una anàlisi no paramètric mitjançant el mètode Kaplan-Meier de les variables sociodemogràfiques i clíniques, per a determinar els factors pronòstics de fragilitat segons l'Índex Fràgil-VIG, de fragilitat segons el Short Physical Performance Battery, de dependència per a les activitats bàsiques de la vida diària, i de mortalitat. Posteriorment es procedix a realitzar anàlisi multivariants mitjançant el model de regressió de Cox. Per al desenvolupament dels models, se seguix l'estratègia suggerida per Collett. Prèviament, es realitza la validació de l'Índex Fràgil-VIG respecte al Short Physical Performance Battery. Respecte a l'anàlisi no paramètric, van ser factors pronòstics de fragilitat segons l'Índex Fràgil-VIG l'estat civil, el nivell de cronicitat i el nombre de convivents; factors pronòstics de fragilitat segons el Short Physical Performance Battery el nivell de cronicitat i la fragilitat segons l'Índex Fràgil-VIG; factors pronòstics de dependència per a les activitats bàsiques de la vida diària l'estat civil, la fragilitat segons l'Índex Fràgil-VIG i el nivell de cronicitat; i factors pronòstics de mortalitat van ser la dependència per a les activitats bàsiques de la vida diària, la fragilitat segons l'Índex Fràgil-VIG, el nivell d'estudis, l'estat civil, el nivell de cronicitat i el sexe. En l'anàlisi multivariant, les variables incloses en els models de fragilitat segons l'Índex Fràgil-VIG i la dependència per a les activitats bàsiques de la vida diària, van ser l'estat civil, el nivell de cronicitat i el sexe. En el model multivariant de fragilitat segons el Short Physical Performance Battery van ser significatives les variables nivell de cronicitat i el nombre de convivents. I finalment, en el model multivariant de mortalitat, van resultar significatives les variables nivell d'estudis, el sexe i la fragilitat segons l'Índex Fràgil-VIG. L'Índex Fràgil-VIG va presentar una adequada validesa convergent i discriminativa respecte al Short Physical Performance Battery. Un 20% de les persones van diferir en el diagnòstic de fragilitat entre totes dues eines, presentant perfils diferents. La validació de l'Índex Fràgil-VIG ha enfortit l'ús del mateix per al desenvolupament dels models. Els grups de risc desenvolupats poden ajudar a establir estratègies de salut diferenciades, tant a nivell individual en la consulta com a nivell poblacional. Amb l'objectiu de facilitar la seua implementació en la pràctica clínica diària, s'han desenvolupat nomogrames que permeten visualitzar fàcilment amb l'objectiu de poder disposar de manera gràfica una eina aplicable en la consulta. / [EN] Population aging and its progression is a fact that must be addressed for the future health and social well-being, especially of the elder people, and by extension, of society as a whole. In this sense, frailty, understood as the progressive decline in physiological systems related to age, plays a remarkable role. The study of frailty using the Frail Index-VIG allows patients to be approached in clinical practice with a multidimensional view, thus establishing a situational diagnosis. This thesis is composed of two different parts. A non-parametric analysis is carried out using the Kaplan-Meier method of the sociodemographic and clinical variables to determine the prognostic factors of frailty according to the Frail-VIG Index, frailty according to the Short Physical Performance Battery, dependency for basic activities of the daily life, and mortality. Subsequently, multivariate analysis were performed using the Cox regression model. For the development of the models, we follow the strategy suggested by Collett. Previously, validation of the Frail-VIG Index is carried out regarding the Short Physical Performance Battery. Regarding the non-parametric analysis, marital status, chronicity level and number of cohabitants, were prognostic factors for frailty according to the Frail-VIG Index; chronicity level and frailty according to the Frail-VIG Index were prognostic factors for frailty according to the Short Physical Performance Battery; prognostic factors for dependency in basic activities of daily living were marital status, frailty according to the Frail-VIG Index and chronicity level; and mortality prognostic factors were dependency for basic activities of daily living, frailty according to the Frail-VIG Index, educational level, marital status, chronicity level and sex. In the multivariate analysis, the variables included in the frailty models using the Frail-VIG Index and dependency for basic activities of daily living were marital status, chronicity level and sex. In the multivariate model of frailty according to the Short Physical Performance Battery, the variables chronicity level and number of cohabitants were significant. And finally, in the multivariate mortality model, the variables level of education, sex and frailty according to the Frail-VIG Index were significant. The Frail Index-VIG presented adequate convergent and discriminative validity compared to the Short Physical Performance Battery. 20% of participants differed in the diagnosis of frailty between both tools, by presenting different profiles. The validation of the Frail-VIG Index has firmed up its use for the development of models. The risk groups might help to establish differentiated health strategies, both at the individual level in the clinical practice and at the population level. In order to facilitate the clinical practice, we developed nomograms that allow an easy visualization of the different risks. / Camacho Torregrosa, S. (2024). Modelización matemática de la fragilidad valorada mediante el Índice Frágil-VIG y el SPPB, de la dependencia para las actividades básicas de la vida diaria y de la mortalidad en población general de 70 años o más. Validación del Índice Frágil-VIG respecto al SPPB [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/205710
472

台灣股票市場散戶存活率之研究 / How and Why Individual Investors Quit?

陳明憲, Chen, Ming-Hsien Unknown Date (has links)
Who can survive longer and what factors could prolong the trading life of individual investors in the market? This is the questions we ask in the dissertation. Based on our knowledge, there is not any research about the issue of survival analysis on analyzing individual investors in stock market. The paper classifies three possibilities could affect the trading life of investors: personal characteristics, trading behavior, and market condition. In the dissertation, we use tick-by-tick transaction data from the Taiwan Stock Exchange to profile survivors versus non-survivors, to investigate how the traders’ characteristics (such as, gender), trading behaviors (such as the degree of diversification, trading amount and trading frequency) and market condition affect the trading life of investors. We borrow the proportional hazard models proposed by Cox (1972) who used in bio-statistics to analyze the survival rate. Using the Kaplan-Meier curves for male and female, we find that survival functions and hazard rates of female investors have better survival prognosis than the male investors. Different timing of entering results in distinct patterns of survival curves and hazard rates. Investors entering that market in the bull and bear market have a larger survival rate than those who enter the market in normal time during the trading life from 1 to 7 years. Moreover, as the trading life increases larger 7 year, the three curves of bull, bear and normal market conditions, respectively, appear to get closer, suggesting that if trading life is shorter than 7 years, the investors entering in the bull and bear markets seemly have lower hazard ratio than that in the normal market to leave the market. Finally, the results of Cox’s proportional hazard model show that female investors stay in the market 74 days longer than the male. Trading cycle increasing by one day will prolong the traders in the market by 4.8 days. Average volume per trade measured in ten thousands does not have economic effect on the trading duration, although its estimate is statistically significant. A one percentage increase of portfolio return will reduce about 151 days of the trading life. One more stock in the portfolio will prolong about 133 days in the trading life. The effect on the trading duration of trading performance of those who enter in the bull market is positive. / Who can survive longer and what factors could prolong the trading life of individual investors in the market? This is the questions we ask in the dissertation. Based on our knowledge, there is not any research about the issue of survival analysis on analyzing individual investors in stock market. The paper classifies three possibilities could affect the trading life of investors: personal characteristics, trading behavior, and market condition. In the dissertation, we use tick-by-tick transaction data from the Taiwan Stock Exchange to profile survivors versus non-survivors, to investigate how the traders’ characteristics (such as, gender), trading behaviors (such as the degree of diversification, trading amount and trading frequency) and market condition affect the trading life of investors. We borrow the proportional hazard models proposed by Cox (1972) who used in bio-statistics to analyze the survival rate. Using the Kaplan-Meier curves for male and female, we find that survival functions and hazard rates of female investors have better survival prognosis than the male investors. Different timing of entering results in distinct patterns of survival curves and hazard rates. Investors entering that market in the bull and bear market have a larger survival rate than those who enter the market in normal time during the trading life from 1 to 7 years. Moreover, as the trading life increases larger 7 year, the three curves of bull, bear and normal market conditions, respectively, appear to get closer, suggesting that if trading life is shorter than 7 years, the investors entering in the bull and bear markets seemly have lower hazard ratio than that in the normal market to leave the market. Finally, the results of Cox’s proportional hazard model show that female investors stay in the market 74 days longer than the male. Trading cycle increasing by one day will prolong the traders in the market by 4.8 days. Average volume per trade measured in ten thousands does not have economic effect on the trading duration, although its estimate is statistically significant. A one percentage increase of portfolio return will reduce about 151 days of the trading life. One more stock in the portfolio will prolong about 133 days in the trading life. The effect on the trading duration of trading performance of those who enter in the bull market is positive.
473

HOME-BASED REHABILITATION AND ITS IMPACT ON HOSPITAL UTILIZATION

Knott, T. CHRISTINE 27 June 2013 (has links)
There is compelling evidence for the effectiveness of home-based occupational therapy and physiotherapy rehabilitation for community dwelling elderly who may struggle with basic activities and the functions of daily living and mobility. Nonetheless, an estimated 2% of home care’s elderly clients receive these therapies. Ontario’s home care data indicates that 78% of clients that could benefit from these specific therapies are not receiving them. The study examined a subset of elderly clients receiving home care following a hospital discharge during 2009-2010. The aim of this study was to: understand the difference between those home care clients who received occupational therapy or physiotherapy and those who did not; and determine if receiving these therapies impacted the utilization of hospital emergency departments and inpatient admissions. A retrospective cohort design and multivariate and survival analysis of hospital and home care administrative data structured the study. Results suggest that home-based rehabilitation is offered to a minority of the home care population. Distinct client characteristics and process variables significantly associated with the increased likelihood of receiving home-based occupational and physical therapies included: clients who were older, females, admitted to home care from hospital inpatient units, assessed as non-acute for clinical and service needs and required more home making support and assistance with activities of daily living. Almost one quarter of the total sample returned to hospital. Visits to emergency departments accounted for the greater part of hospital utilization and primarily for sub-acute general symptoms and signs, post-procedural complications, infections or acute episodes from chronic obstructive pulmonary disease and renal failure. Slightly over half of the clients returning to hospital did not receive home-based rehabilitation. Clients who received occupational therapy returned to the hospital sooner following their home care admission whereas clients receiving physiotherapy spent the longest time before rehospitalizing. The majority of the clients receiving occupational therapy were admitted to home care having just resolved sub-acute conditions or symptoms, many of which are known to influence functional and physical decline. Moreover, analysis of process variables indicated that the wait time for a referral to occupational therapy was two times longer compared to physiotherapy. These same clients also waited, on average, over one month before an occupational therapist’s first visit. The need to discriminate who receives home-based rehabilitation is essential to understanding how specific therapies contribute to improving systems outcomes. This study is the first examination that focuses specifically on home-based occupational therapy and physiotherapy rehabilitation and the client characteristics and process variables associated with receiving/not receiving these therapies and the impact these factors have on the time-to-rehospitalization. / Thesis (Ph.D, Rehabilitation Science) -- Queen's University, 2013-06-27 12:24:53.085
474

Atrial fibrillation in cardiac surgery

Ahlsson, Anders January 2008 (has links)
Atrial fibrillation (AF) is the most common arrhythmia seen in clinical practice. In cardiac surgery, one-third of the patients experience episodes of AF during the first postoperative days (postoperative AF), and patients with preoperative AF (concomitant AF) can be offered ablation procedures in conjunction with surgery, in order to restore ordinary sinus rhythm (SR). The aim of this work was to study the relation between postoperative AF and inflammation; the long-term consequences of postoperative AF on mortality and late arrhythmia; and atrial function after concomitant surgical ablation for AF. In 524 open-heart surgery patients, C-reactive protein (CRP) serum concentrations were measured before and on the third day after surgery. There was no correlation between levels of CRP and the development of postoperative AF. All 1,419 patients with no history of AF, undergoing primary aortocoronary bypass surgery (CABG) in the years 1997–2000 were followed up after 8.0 years. The mortality rate was 191 deaths/1,000 patients (19.1%) in patients with no AF and 140 deaths/419 patients (33.4%) in patients with postoperative AF. Postoperative AF was an age-independent risk factor for late mortality, with a hazard ratio (HR) of 1.56 (95% CI 1.23–1.98). Postoperative AF patients had a more than doubled risk of death due to cerebral ischaemia, myocardial infarction, sudden death, and heart failure compared with patients without AF. All 571 consecutive patients undergoing primary CABG during the years 1999–2000 were followed-up after 6 years. Questionnaires were obtained from 91.6% of surviving patients and an electrocardiogram (ECG) from 88.3% of all patients. In postoperative AF patients, 14.1% had AF at follow-up, compared with 2.8% of patients with no AF at surgery (p<.001). An episode of postoperative AF was found to be an independent risk factor for development of late AF, with an adjusted risk ratio (RR) of 3.11 (95% CI 1.41–6.87). Epicardial microwave ablation was performed in 20 open-heart surgery patients with concomitant AF. Transthoracic echocardiography was performed preoperatively and at 6 months postoperatively. At 12 months postoperatively 14/19 patients (74%) were in SR with no anti-arrhythmic drugs. All patients in SR had preserved left and right atrial filling waves (A-waves) and Tissue velocity echocardiography (TVE) showed preserved atrial wall velocities and atrial strain. In conclusion, postoperative AF is an independent risk factor for late mortality and later development of AF. There is no correlation between the inflammatory marker CRP and postoperative AF. Epicardial microwave ablation of concomitant AF results in SR in the majority of patients and seems to preserve atrial mechanical function.
475

Prognostički faktori za preživljavanje kod gerijatrijskih bolesnika sa uznapredovalim stadijumom nemikrocelularnog karcinoma bronha / Prognostic factors for survival in geriatric patients with advanced stage of non-small cell lung cancer

Sazdanić-Velikić Danica 23 September 2016 (has links)
<p>UVOD: Savremenim dijagnostičkim i terapijskim dostignućima, kao i unapređenjem preventivnih mera produžen je životni vek ljudi. Starenje stanovni&scaron;tva je fenomen koji zahvata ceo svet. Povećanje broja starijeg stanovni&scaron;tva je udruženo sa porastom broja obolelih od karcinoma u ovoj starosnoj grupi, jer je starenje samo po sebi riziko faktor za nastanak karcinoma. Incidenca pojave karcinoma naglo raste od 50-te godine života sa vrhom u 80-toj godini života. U osoba starijih od 65 godina se dijagnostikuje 58% svih karcinoma, a 30% u starijih od 70 godina. Godine starosti nisu kontraindikaciija za sprovođenje hemioterapije kod starih bolesnika sa karcinomom. Starenje je povezano sa izmenjenom farmakodinamikom i farmakokinetikom antitumorskih lekova i povećanom osetljivo&scaron;ću normalnog tkiva na toksične komplikacije, te je odluka kliničara kod davanja hemioterapije ovoj starosnoj kategoriji bolesnika sa karcinomom uvek vrlo kompleksna i zahteva dobru procenu i odgovarajuću selekciju bolesnika za ovaj tretman. MATERIJAL I METODE: Doktorska disertacija obuhvata rezultate delom restrospektivnog, a delom prospektivnog opservacionog istraživanja sprovedenog u periodu 01.01.2011. do 31.12.2013.godine u Institutu za plućne bolesti Vojvodine u Sremskoj Kamenici, u kojem je praćeno 152 bolesnika starosti 65 i vi&scaron;e godina kod kojih je dijagnostikovan nemikrocelularni karcinom bronha u uznapredovalom stadijumu bolesti, a koji su lečeni kombinovanim hemioterapijskim režimom na bazi platine. Kao prognostički faktori su uzeti: starosna dob bolesnika (grupa mlađih od 75 godina i starih 75 i vi&scaron;e godina), pol, navika pu&scaron;enja cigareta (pu&scaron;ač, nepu&scaron;ač, biv&scaron;i pu&scaron;ač), navika konzumiranja alkohola, performans status (prema ECOG-Eastern Cooperative Oncology Group skali) u momentu postavljanja dijagnoze, patohistolo&scaron;ki tip tumora (adenokarcinom, skvamozni karcinom, drugo), stadijum bolesti (IIIb, IV), veličina tumora (manje od 6 cm i 6 cm i vi&scaron;e), TNM status prema klasifikaciji tumora (7.revizija), parametri krvne slike (vrednosti leukocita, hemoglobina, trombocita), biohemijski parametri (vrednosti laktat-dehidrogenaze (LDH), alkalne fosfataze, aspartat- aminotransferaze (AST), alanin-aminotransferaze (ALT), kalijuma, natrijuma, bilirubina) na početku terapije, komorbiditeti u momentu postavljanja dijagnoze (broj komorbiditeta po sistemima, Charlson index), simptomi bolesti (ka&scaron;alj, hemoptizije, otežano disanje, bol u grudnom ko&scaron;u, promuklost, smetnje gutanja, sindrom gornje &scaron;uplje vene, bol u kostima, simptomi od strane centralnog nervnog sistema, povi&scaron;ena telesna temperatura), gubitak na telesnoj masi (vi&scaron;e od 5% u prethodnih 6 meseci), indeks telesne mase (&lt;18,5kg/m&sup2; pothranjen, 18,5-24,9kg/m&sup2; normalno uhranjen, 25-29,9kg/m&sup2; prekomerna telesna masa, ˃30kg/m&sup2; gojaznost). Svi potencijalni prognostički faktori su evaluirani univarijantnom analizom, a potom su svi faktori rizika za koje je utvrđena značajnost analizirani primenom multivarijantne logističke regresije, u cilju prepoznavanja nezavisnih prediktora za dvogodi&scaron;nje preživljavanje. Za otkrivanje nezavisnih prediktora preživljavanja na dve godine je primenjena binarna logistička regresiona analiza, a kao potencijalni prediktori su bile sledeće varijable: starost ispod 75 godina, pu&scaron;ačka navika, patohistolo&scaron;ki tip karcinoma, stadijum bolesti IV, T4 status, M1b status, prisustvo respiratornog komorbiditeta, otežano disanje, bol u grudima. Kumulativno preživljavanje je prikazano Kaplan-Meier-ovim krivama. Primenom multivarijantne Cox- regresione analize su dobijeni nezavisni prediktori kumulativnog preživljavanja. Iz dobijenih prognostičkih faktora koji se izdvajaju kao nezavisni prediktori za preživljavanje su kreirani matematički modeli za dvogodi&scaron;nje preživljavanje. CILJ ISTRAŽIVANJA: Utvrditi uticaj pojedinih prognostičkih faktora na dvogodi&scaron;nje preživljavanje ovih bolesnika i iz toga izvesti matematički model za stratifikaciju ovih bolesnika u odnosu na dvogodi&scaron;nje preživljavanje. REZULTATI: Analizom prognostičkih faktora je utvrđeno da grupa bolesnika starih 75 godina i vi&scaron;e ima ne&scaron;to duže dvogodi&scaron;nje preživljavanje od grupe bolesnika mlađih od 75 godina, ali bez statističke značajnosti, bolesnici sa tumorom veličine 6 cm i vi&scaron;e imaju kraće dvogodi&scaron;nje preživljavanje u odnosu na bolesnike sa tumorom manjim od 6 cm, bolesnici kod kojih je u momentu postavljanja dijagnoze T status tumora bio T4, a M status M1b imaju kraće dvogodi&scaron;nje preživljavanje, bolesnici kod kojih je na početku tretmana u laboratorijskim nalazima bila prisutna anemija i povi&scaron;ene vrednosti LDH imaju kraće dvogodi&scaron;nje preživljavanje, prisustvo vi&scaron;e komorbiditeta utiče na kraće preživljavanje, bolesnici sa gubitkom na telesnoj masi većim od 5% u periodu 6 meseci pre postavljanja dijagnoze bolesti imaju kraće dvogodi&scaron;nje preživljavanje. Kreirana su dva matematička modela (jedan za preživljavanje na 2 godine i jedan za kumulativno preživljavanje) za stratifikaciju gerijatrijskih bolesnika sa uznapredovalim stadijumom nemikrocelularnog karcinoma bronha lečenih hemioterapijom na bazi platine u odnosu na dvogodi&scaron;nje preživljavanje. ZAKLJUČAK: Dobijeni matematički modeli za preživljavanje gerijatrijskih bolesnika sa uznapredovalim stadijumom nemikrocelularnog karcinoma bronha lečenih hemioterapijom na bazi platine na jednostavan način stratifikuju bolesnike u odnosu na preterapijske prognostičke faktore za razliku od sveobuhvatne gerijatrijske procene koja je vremenski zahtevna procedura i zahteva obučen kadar.</p> / <p>INTRODUCTION: Nowadays life expectancy is prolonged due to modern diagnostic and therapy achievements, as well as promotion of preventive measurements. Aging of population is a phenomenon in the whole world. Increasing number of elderly population is accompanied with the increased number of diagnosed cancer in this age group, because the aging themselves is a risk factor for development of cancer. The appearance of cancer rapidly rises from the age of fifty with the peak at the age of eighty. 58% of cancer diagnoses are in the people older than sixty-five years and 30% in people older than seventy years. The age is not contraindication for chemotherapy treatment in older patient with cancer. The aging is associated with disturbed pharmacodynamics and pharmacokinetics of antitumor drugs and increased susceptibility of normal tissue for toxic complications, therefore clinical decision for introducing chemotherapy is very complex and requires good assessment and proper selection of the patients for this treatment. MATERIAL AND METHODS: This doctoral thesis includes results of partly retrospective and partly prospective observational research conducted in the period 01.01.2011. until 31.12.2013. at the Institute for pulmonary diseases of Vojvodina in Sremska Kamenica, which includes 152 lung cancer patients 65 and more years old with diagnosed non-small cell lung cancer in advanced stage treated with combined platinum based chemotherapy regimen. These prognostic factors are included: age of patients (group &lt;75 years, group &ge;75 years old), sex, smoking cessation (smoker, former smoker, non smoker), alcohol consuming habit, performance status (according to the ECOG-Eastern Cooperative Oncology Group scale) in the moment of confirmed diagnosis, pathohistological type of tumor (adenocarcinoma, squamous cell carcinoma, other), stage of disease (IIIb, IV), tumor size (&lt;6cm and &ge;6cm), TNM status according tumor classification (7th revision), blood count parameters (leucocyte, hemoglobin level, thrombocyte), biochemical parameters (lactate-dehydrogenase level (LDH), alkaline phosphatase level, aspartate aminotransferase level (AST), alanine aminotransferase level (ALT), potassium level, sodium level, bilirubin level) on the start of the chemotherapy, comorbidities at the moment of diagnosis (number of comorbid conditions, Charlson index), symptoms of the disease (cough, hemoptysis, dyspnea, chest pain, hoarseness, swallowing difficulties, caval venae compression symptoms, bone pain, central nervous symptoms, increased body temperature), weight loss (˃ 5% in the previous 6 months), body mass index (&lt;18,5kg/m&sup2; underweight 18,5-24,9kg/m&sup2; normal weight, 25-29,9kg/m&sup2; overweight , ˃30kg/m&sup2; obese). All potential prognostic factors were evaluated with univariante analysis, and after that all factors with confirmed significance were analysed with multivariante logistic regression, in order to identify independent predictors for 2-year survival. Binary logistic regression analysis was applied for identifying independent predictors for 2-years survival and those variables were analysed : age &lt;75 years, smoking cessation, pathohistological type of cancer, stage of disease IV, T4 status, M1b status, presence of respiratory comorbidity, dyspnea, chest pain. Cumulative survival of those patients was shown with Kaplan-Meier prognostic curves. Two mathematical model for 2-year survival was created from the factors confirmed as independent predictors for survival. AIM: This research objectives were to determine the influence of certain prognostic factors on 2-years survival of those patients and to create mathematical model for stratification of those patients related to 2-years survival. RESULTS: Univariante analysis confirmed that the group of patients older than 75 years and more have had better 2-year survival than group of patient younger than 75 year, but without the statistically significance, patients with tumor size &ge;6cm have had worst 2-year survival in comparison with patients with tumor size &lt;6cm, patients with tumor status T4 at the moment of diagnosis and M status M1b have had the shorter 2-year survival, patients with anemia and increased LDH level on the start of the chemotherapy treatment have had shorter 2-year survival, the presence of more comorbid conditions at the moment of diagnosis influence on shorter 2-year survival, patients with weight loss more than 5% in the previous 6 months have had shorter 2-year survival. Two mathematical models were created (one for 2-year survival and the other for the cumulative survival) for stratification of elderly patients with advanced staged non-small cell lung cancer treated with combined platinum based chemotherapy regimen related to 2-year survival. CONSLUSION: Created mathematical models for stratification of elderly patients with advanced staged non-small cell lung cancer treated with combined platinum based chemotherapy regimen more easily stratify patients compared to pretreatment prognostic factors as opposed to comprehensive geriatric assessment which is time-consuming procedure and requires trained personnel.</p>
476

An integrated genomic approach for the identification and analysis of single nucleotide polymorphisms that affect cancer in humans

Repapi, Emmanouela January 2013 (has links)
The identification of genetic variants such as single nucleotide polymorphisms (SNPs), which affect cancer progression, survival and response to treatments could help in the design of better prevention and treatment strategies. Genome-wide association studies (GWAS) have provided the first step of identifying SNPs associating with cancer risk. However, identifying the causal SNPs responsible for the associations has proven challenging, and GWAS have not been successful for time-to-event phenotypes such as cancer progression, due to the insurmountable obstacle of the large sample size needed. The aim of this thesis is to design and implement strategies that combine the identification of SNPs significantly associated with cancer, focusing on time-to-event phenotypes, with detailed bioinformatics analysis to allow for further experimental validation and modelling, to better understand cancer-associated genomic loci and accelerate their incorporation into the clinic. First, a methodology that utilises the Random Survival Forest is developed and combined with a bioinformatics analysis that ranks SNPs according to their potential to result in differential protein levels or activity, in order to identify SNPs that affect the progression of B-cell chronic lymphocytic leukaemia. Next, an analysis that aims to extend our understanding of the role of SNPs in mediating the cellular responses to chemotherapeutic agents is applied. SNPs that could associate with differential cellular growth responses in cancer cell line panels are identified, and their association with the differential survival of cancer patients is explored. Finally, the potential roles of SNPs in affecting the transcriptional regulation of key cancer genes resulting in differential cancer risk are assessed. First, by focusing on SNPs in an important transcription factor binding motif that has been shown to be extremely sensitive to single base pair changes (the E-box) and next, by exploring the possibility that polymorphic transcription factor binding sites could underlie the significant associations noted in cancer GWAS.
477

STATISTICAL MODELS AND ANALYSIS OF GROWTH PROCESSES IN BIOLOGICAL TISSUE

Xia, Jun 15 December 2016 (has links)
The mechanisms that control growth processes in biology tissues have attracted continuous research interest despite their complexity. With the emergence of big data experimental approaches there is an urgent need to develop statistical and computational models to fit the experimental data and that can be used to make predictions to guide future research. In this work we apply statistical methods on growth process of different biological tissues, focusing on development of neuron dendrites and tumor cells. We first examine the neuron cell growth process, which has implications in neural tissue regenerations, by using a computational model with uniform branching probability and a maximum overall length constraint. One crucial outcome is that we can relate the parameter fits from our model to real data from our experimental collaborators, in order to examine the usefulness of our model under different biological conditions. Our methods can now directly compare branching probabilities of different experimental conditions and provide confidence intervals for these population-level measures. In addition, we have obtained analytical results that show that the underlying probability distribution for this process follows a geometrical progression increase at nearby distances and an approximately geometrical series decrease for far away regions, which can be used to estimate the spatial location of the maximum of the probability distribution. This result is important, since we would expect maximum number of dendrites in this region; this estimate is related to the probability of success for finding a neural target at that distance during a blind search. We then examined tumor growth processes which have similar evolutional evolution in the sense that they have an initial rapid growth that eventually becomes limited by the resource constraint. For the tumor cells evolution, we found an exponential growth model best describes the experimental data, based on the accuracy and robustness of models. Furthermore, we incorporated this growth rate model into logistic regression models that predict the growth rate of each patient with biomarkers; this formulation can be very useful for clinical trials. Overall, this study aimed to assess the molecular and clinic pathological determinants of breast cancer (BC) growth rate in vivo.
478

Validation des modèles statistiques tenant compte des variables dépendantes du temps en prévention primaire des maladies cérébrovasculaires

Kis, Loredana 07 1900 (has links)
L’intérêt principal de cette recherche porte sur la validation d’une méthode statistique en pharmaco-épidémiologie. Plus précisément, nous allons comparer les résultats d’une étude précédente réalisée avec un devis cas-témoins niché dans la cohorte utilisé pour tenir compte de l’exposition moyenne au traitement : – aux résultats obtenus dans un devis cohorte, en utilisant la variable exposition variant dans le temps, sans faire d’ajustement pour le temps passé depuis l’exposition ; – aux résultats obtenus en utilisant l’exposition cumulative pondérée par le passé récent ; – aux résultats obtenus selon la méthode bayésienne. Les covariables seront estimées par l’approche classique ainsi qu’en utilisant l’approche non paramétrique bayésienne. Pour la deuxième le moyennage bayésien des modèles sera utilisé pour modéliser l’incertitude face au choix des modèles. La technique utilisée dans l’approche bayésienne a été proposée en 1997 mais selon notre connaissance elle n’a pas été utilisée avec une variable dépendante du temps. Afin de modéliser l’effet cumulatif de l’exposition variant dans le temps, dans l’approche classique la fonction assignant les poids selon le passé récent sera estimée en utilisant des splines de régression. Afin de pouvoir comparer les résultats avec une étude précédemment réalisée, une cohorte de personnes ayant un diagnostique d’hypertension sera construite en utilisant les bases des données de la RAMQ et de Med-Echo. Le modèle de Cox incluant deux variables qui varient dans le temps sera utilisé. Les variables qui varient dans le temps considérées dans ce mémoire sont iv la variable dépendante (premier évènement cérébrovasculaire) et une des variables indépendantes, notamment l’exposition / The main interest of this research is the validation of a statistical method in pharmacoepidemiology. Specifically, we will compare the results of a previous study performed with a nested case-control which took into account the average exposure to treatment to : – results obtained in a cohort study, using the time-dependent exposure, with no adjustment for time since exposure ; – results obtained using the cumulative exposure weighted by the recent past ; – results obtained using the Bayesian model averaging. Covariates are estimated by the classical approach and by using a nonparametric Bayesian approach. In the later, the Bayesian model averaging will be used to model the uncertainty in the choice of models. To model the cumulative effect of exposure which varies over time, in the classical approach the function assigning weights according to recency will be estimated using regression splines. In order to compare the results with previous studies, a cohort of people diagnosed with hypertension will be constructed using the databases of the RAMQ and Med-Echo. The Cox model including two variables which vary in time will be used. The time-dependent variables considered in this paper are the dependent variable (first stroke event) and one of the independent variables, namely the exposure.
479

AN ASSOCIATION STUDY BETWEEN ADULT BLOOD PRESSURE AND TIME TO FIRST CARDIOVASCULAR DISEASE

Pu, Yongjia 01 January 2015 (has links)
BACKGROUND: Several studies have demonstrated the association between the time to hypertension event and multiple baseline measurements for adults, yet other survival cardiovascular disease (CVD) outcomes such as high cholesterol and heart attack have been somewhat less considered. The Fels Longitudinal Study (FLS) provides us an opportunity to connect adult blood pressure (BP) at certain ages to the time to first CVD outcomes. The availability of long-term serial BP measurements from FLS also potentially allows us to evaluate if the trend of the measured BP biomarkers over time predicts survival outcomes in adulthood through statistical modeling. METHODS: When the reference standard is right-censored time-to-event (survival) outcome, the C index or concordance C, is commonly used as a summary measure of discrimination between a survival outcome that is possibly right censored and a predictive-score variable, say, a measured biomarker or a composite-score output from a statistical model that combines multiple biomarkers. When we have subjects longitudinally followed up, it is of primary interest to assess if some baseline measurements predict the time-to-event outcome. Specifically, in this study, systolic blood pressure, diastolic blood pressure, as well as their variation over time, are considered predictive biomarkers, and we assess their predictive ability for certain time-to-event outcomes in terms of the C index. RESULTS: There are a few summary C index differences that are statistically significant in predicting and discriminating certain CVD metric at certain age stage, though some of these differences are altered in the presence of medicine treatment and lifestyle characteristics. The variation of systolic BP measures over time has a significantly different predicting ability comparing with systolic BP measures at certain given time point, for predicting certain survival outcome such as high cholesterol level. CONCLUSIONS: Adult systolic and diastolic BP measurements may have significantly different ability in predicting time to first CVD events. The fluctuation of BP measurements over time may have better association than BP measurement at a single baseline time point, with the time to first CVD events.
480

Caractérisation de l'hétérogénéité tumorale sur des images issues de la tomographie par émission de positons (TEP) / Intra-tumor heterogeneity characterization on positron emission tomography (PET)

Tixier, Florent 30 April 2013 (has links)
Le cancer est chaque année responsable de 7,6 millions de décès dans le monde. L'amélioration des traitements constitue donc un enjeu majeur de santé publique. Il a été démontré que l'association d'un diagnostic précoce et d'un traitement efficace était associée à un impact significatif sur la survie des patients. De nombreux facteurs pronostics de la survie ont été identités et sont actuellement utilisés en routine clinique. Ce diagnostic est souvent réalisé en partieà l'aide de l'imagerie de Tomographie par Emission de Positons (TEP), cette dernière s'étantavérée être un outil très performant pour l'identification des tumeurs et métastases dans uncertain nombre de modèles de cancer. La TEP fait partie des modalités d'imagerie fonctionnelleet a donc le potentiel de fournir des informations liées à la biologie sous-jacente des cancers.Toutefois, du fait de sa faible résolution spatiale, elle n'avait que très peu été utilisée avec cet objectif.Ce travail de thèse a consisté à étudier des paramètres quantitatifs pouvant être extraitsde ces images, plus spécifiquement ceux permettant la caractérisation de l'hétérogénéité intratumorale. Nous avons pu identifier un ensemble de paramètres issus de l'analyse de texture quisont reproductibles, robustes aux effets de volume partiel et à la méthode de segmentation, etvraisemblablement liés à la physiologie tumorale. Nous avons également pu mettre en évidencele potentiel de ces paramètres extraits d'images de diagnostic, pour contribuer à la prédiction dela réponse thérapeutique ainsi que comme facteur pronostic. Ces nouveaux indices quantitatifspourraient à relativement court terme venir compléter les facteurs de référence courammentutilisés aujourd'hui en oncologie pour la prise en charge thérapeutique des patients. / Cancer is responsible every year for the death of 7.6 million people. Treatments improvement is thus of the greatest importance regarding public health. The association of an early diagnosis with an efficient treatment was shown to lead to a significant impact on patients survival rates. Numerous prognostic factors have been identified and are now being used in clinical routine. Nowadays, Positron Emission Tomography (PET) imaging is often used for tumor and metastasis identification because of its established accuracy in numerous cancer models. PET belongs to the functional imaging techniques and may potentially therefore provide information relative to cancer biology. Nevertheless, because of its low spatial resolution, this technique has not been extensively considered for such a purpose. This thesis work aimed at studying quantitative parameters that could be extracted from PET images through texture analysis, in order to characterize tumor heterogeneity. We identified a set of reproducible parameters, robust with respect to partial volume effects as well as segmentation methods that are probably related to the tumor physiology. We have also demonstrated the power of these parameters obtained from diagnostic images for contributing in predicting the therapeutic response as prognostic factors. These new quantitative parameters could in the relatively short term be utilized complementarily to standard oncology factors for patient management purposes.

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