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Business demography dynamics in Portugal: a semi-parametric survival analysis

Nunes, Alcina; Sarmento, Elsa
Fonte: The Institute for Business and Finance Research Publicador: The Institute for Business and Finance Research
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
36.21%
We address the post-entry performance of new Portuguese firms by investigating the structural characteristics of the hazard and survival functions, using semi-parametric survival analysis for the total economy and its broad sectors. In order to approach the prevalence of some stylized facts and determinants of new firm survival, a new entrepreneurship database was produced, using the administrative data of Quadros de Pessoal, following the Eurostat/OECD´s internationally comparable business demography methodology. In line with the literature, we find that firms that start small and experience faster post-entry growth, face a higher probability of survival. Firm’s current size dimension matters particularly for the Services sector probability of survival. In industries characterized by high entry rates, post-entry survival is more difficult. This happens mostly in Agriculture and the Construction sectors in Portugal. We find a different result from the literature, for the effect of industry growth in survival rates. Firms operating in industries which are growing faster, seem to suffer from a higher probability of failure. The combined effect of turbulence and entry and growth variables help explaining this unexpected effect of industry growth on survival probabilities. By correcting heterogeneity...

Business survival in portuguese regions

Nunes, Alcina; Sarmento, Elsa
Fonte: GEE/GPEARI Publicador: GEE/GPEARI
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
36.21%
This work addresses the post-entry performance of employer enterprises for seven regions in Portugal, at the NUT II level, by investigating the structural characteristics of survival, using non-parametric and semi-parametric methods, during the period 1985 to 2007. The last decades of the 20th century were characterized by a period of creative destruction in Portugal. In particular, regions such as Norte, Algarve and Madeira show the highest growth rates in enterprise births, deaths and firm churn. After 2000, firms´ births and deaths are relatively less turbulent. In the non-parametric analysis, we identify statistically significant disparities among regions. Norte has the lowest survival rate and Centro holds the longest surviving firms. The survival gap between these two regions widens over time. Concerning the semi-parametric analysis, firm’s current size dimension is a strong determinant for the probability of survival, particularly in the Norte and Açores. In industries characterized by high entry rates at the moment of a firm’s birth, post-entry survival becomes harder, especially in the south and in the Portuguese archipelagos, the regions with the lowest number of active employer enterprises. A higher entry rate combined with fast growth rates for any given industry also generates a shorter duration of firms. Manufacturing is the sector where more firms are more likely to abandon the market...

A brief survival analysis framework for portuguese firms

Nunes, Alcina; Sarmento, Elsa
Fonte: Clute Institute Publicador: Clute Institute
Tipo: Conferência ou Objeto de Conferência
Português
Relevância na Pesquisa
36.21%
We address the post-entry performance of new Portuguese firms by investigating the structural characteristics of the hazard and survival functions, using non-parametric and semi-parametric survival analysis for the total economy and its broad sectors. In order to approach the prevalence of some stylized facts and determinants of new firm survival, a new entrepreneurship database was produced, using the administrative data of Quadros de Pessoal, following the Eurostat/OECD´s internationally comparable business demography methodology. In line with the literature, we find that firms that start small and experience faster post-entry growth, face a higher probability of survival. Firm’s current size dimension matters particularly for the services sector probability of survival. In industries characterized by high entry rates, post-entry survival is more difficult. This happens mostly in Agriculture and the Construction sectors in Portugal. We find a different result from the literature, for the effect of industry growth in survival rates. Firms operating in industries which are growing faster, seem to suffer from a higher probability of failure. The combined effect of turbulence and entry and growth variables help explaining this unexpected effect of industry growth on survival probabilities.

Nodules Less Than 20 mm and Vascular Invasion are Predictors of Survival in Small Hepatocellular Carcinoma

KIKUCHI, Luciana O. O.; PARANAGUA-VEZOZZO, Denise C.; CHAGAS, Aline L.; MELLO, Evandro S.; ALVES, Venancio A. F.; FARIAS, Alberto Q.; PIETROBON, Ricardo; CARRILHO, Flair J.
Fonte: LIPPINCOTT WILLIAMS & WILKINS Publicador: LIPPINCOTT WILLIAMS & WILKINS
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
36.23%
Background: The aims of this study were to analyze the overall survival of patients with cirrhosis and small hepatocellular carcinoma (HCC) and identify independent pretreatment predictors of survival in Brazil. Methods: Between 1998 and 2003, 74 patients with cirrhosis and small HCC were evaluated. Predictors of survival were identified using the Kaplan-Meier survival curves and the Cox model. Results: The overall survival rates were 80%, 41%, and 17% at 12, 36, and 60 months, respectively. The mean length of follow-up after HCC diagnosis was 23 months (median 22 mo, range: I to 86 mo) for the entire group. Univariate analysis showed that model for endstage liver disease (MELD) score (P = 0.016), Child-Pugh classification (P = 0.007), alpha-fetoprotein level (P = 0.006), number of nodules (P = 0.041), tumor diameter (P = 0.009), and vascular invasion (P < 0.0001) were significant predictors Of Survival. Cox regression analysis identified vascular invasion (relative risk = 14.60, confidence interval 95% = 3.3-64.56, P < 0.001) and tumor size > 20 mm (relative risk = 2.14, confidence interval 95% = 1.07-4.2, P = 0.030) as independent predictors of decreased survival. Treatment of HCC was related to increased overall survival. Conclusions: Identification of HCC smaller than 20 mm is associated with longer survival. Presence of vascular invasion...

Corneal graft survival after therapeutic keratoplasty for Acanthamoeba keratitis

KASHIWABUCHI, Renata T.; FREITAS, Denise de; ALVARENGA, Lenio S.; VIEIRA, Luiz; CONTARINI, Patricia; SATO, Elcio; FORONDA, Annette; HOFLING-LIMA, Ana Luisa
Fonte: WILEY-BLACKWELL Publicador: WILEY-BLACKWELL
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
36.21%
Purpose: To describe corneal graft survival and visual outcome after therapeutic penetrating keratoplasty in patients with Acanthamoeba keratitis (AK) that is unresponsive to clinical treatment. Methods: Retrospective study. Thirty-two patients with AK who underwent therapeutic penetrating keratoplasty (tPK) from August 1996 to August 2005 were included. Data relating to clinical features, visual acuity, surgical technique, graft survival and complications were collected. Graft survival was evaluated by the Kaplan-Meier method and comparisons were performed using the Log-rank test. Results: Most patients (62.5%) were female. Mean age [+/- standard deviation (SD)] was 35 (+/- 13) years (range 15-68 years). All patients were contact lens wearers. Eighteen patients (56%) presented paralytic mydriasis and glaucoma during the treatment. Thirteen patients (40%) developed glaucoma after surgery; eight of them (61%) required a second PK because of graft failure. Of the 32 keratoplasty eyes, 56.2% presented graft failure at any follow-up point. Forty-five per cent of graft failures occurred before the 12 month follow-up, so 55% remained clear in the first year after surgery. Twelve patients underwent a second PK; seven of them failed and 45% were clear at 1 year. Two patients presented graft recurrence of amoebic infection. There was no significant difference in graft survival when eyes with or without mydriasis were compared (P = 0.40). Eyes with glaucoma presented a significantly shorter graft survival (P = 0.01). Conclusion: Penetrating keratoplasty is a treatment option for eyes that are unresponsive to clinical treatment infections. However...

The impact of late diagnosis on the survival of patients following their first AIDS-related hospitalization in Belo Horizonte, Brazil

da Costa Oliveira, Maria Tereza; Dias de Oliveira Latorre, Maria do Rosario; Greco, Dirceu Bartolomeu
Fonte: ROUTLEDGE JOURNALS, TAYLOR & FRANCIS LTD; ABINGDON Publicador: ROUTLEDGE JOURNALS, TAYLOR & FRANCIS LTD; ABINGDON
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
36.21%
The purpose of this study is to estimate the survival probability of patients following their first admission for the treatment of AIDS to an infectious disease reference hospital in Belo Horizonte, Brazil, during 2005. Study subjects were monitored during a 12-month period to identify factors associated with survival probability. Late diagnosis was recorded among many of the 250 study subjects: almost half (44.8%) were diagnosed less than 30 days prior to or during their hospitalization. A high mortality rate was also detected: 39.6% of the subjects died during the 12 months of monitoring. The cumulative survival probability of the cohort group was estimated at 68.0% after 3 months and at 61.2% after 12 months. However, certain patient subgroups analyzed had even lower cumulative survival probabilities after 12 months of monitoring: if diagnosed during hospitalization, it was estimated at only 48.0% and those with no record of antiretroviral treatment had a 48.5% cumulative survival probability. Patients with severe anemia had the lowest survival probability, similar among the two lymphocyte count groups (<1000 mm(3) and >= 1000 mm(3)), the former with a 45.5% survival probability and the latter with a 46.7% one. The proportional death risk was 2.5-fold higher for men residing in other area than the capital city of the State of Minas Gerais and greater metropolitan region when compared with women residing there. The findings of this study highlight the importance of early diagnosis for predicting patient survival and reinforce the necessity off acilitating HIV diagnosis.

Survival of AIDS patients in Sao Paulo-Brazil in the pre- and post-HAART eras: a cohort study

Tancredi, Mariza V; Waldman, Eliseu A
Fonte: BMC Publicador: BMC
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
36.21%
Background Brazil was the first middle-income country to provide free and universal access to AIDS treatment. Understanding the impact of this policy is key to promote ongoing improvement of current intervention strategies. The aim of this study was to compare mortality rates and survival in a cohort of AIDS patients before and after the introduction of antiretrovirals (ARV) and to investigate predictors of survival. Methods A retrospective cohort study of AIDS patients aged 13 years or more living in the city of Sao Paulo was conducted. All patients were recruited from an STD/HIV outpatient clinic between 1988 and 2003 and followed up until 2005. We estimated AIDS mortality rates in person-years (py) and carried out a survival analysis using the Kaplan-Meier method. The Cox proportional hazards model was used to assess predictors of survival in AIDS patients. Results The study cohort comprised 6,594 patients. The yearly mean mortality rates were 17.6, 23.2, and 7.8 per 1,000 py for the study periods 1988–1993, 1994–1996, and 1997–2003, respectively. Median survival time was 13.4 and 22.3 months for patients entering the study in the first and second study periods and survival time was 108 months or more in 72% of those entering the study during 1997–2003. Factors independently associated with shorter survival included: AIDS diagnosis during the 1994–1996 (HR 2.0) and 1988–1993 (HR 3.2) periods; 50 years of age or more (HR 2.0); exposure category of injection drug users (IDU) (HR 1.5); 8 years of schooling or less (HR 1.4); no schooling (HR 2.1); and CD4+ counts between 350 and 500 cells/mm3 (HR 1.2) and less than 350 cells/mm3 at AIDS diagnosis (HR 1.3). Conclusions The study showed a strong impact following the introduction of HAART in 1996 with decreased AIDS mortality...

Registro brasileiro de ressuscitação cardiopulmonar intra-hospitalar: fatores prognósticos de sobrevivência pós-ressuscitação; Brazilian Registry of in-hospital Cardiopulmonary Resuscitation: post-resuscitation survival prognostic factors

Guimarães, Hélio Penna
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 13/06/2011 Português
Relevância na Pesquisa
36.25%
Introdução: Apesar dos avanços e uniformização preconizada pelas diretrizes mundiais de ressuscitação cardiopulmonar (RCP), ainda é insuficiente o conhecimento da efetividade da RCP intra-hospitalar no Brasil. Neste estudo avaliamos variáveis clínicas e demográficas de pacientes submetidos à RCP e preditores independentes associados à sobrevivência imediata (recuperação da circulação espontânea acima de 24h), sobrevivência até a alta hospitalar, em seis e doze meses. Métodos: este estudo transversal incluiu, de forma prospectiva, 763 pacientes em parada cardiorrespiratória (PCR) entre 1º de novembro de 2007 a 1º de novembro de 2010, ocorrida no ambiente intra-hospitalar de 17 hospitais gerais e institutos de especialidades. As manobras de RCP foram executadas em 575 pacientes. Resultados: A modalidade de PCR mais frequente foi a assistolia (40,7%), seguida de atividade elétrica sem pulso (39,3%). A sobrevivência imediata foi de 48,8%, sobrevivência até a alta hospitalar foi de 13%, de 4,3% em seis e de 3,8% em doze meses. Os preditores independentes associados à sobrevivência imediata foram o ritmo inicial em fibrilação ventricular ou taquicardia ventricular sem pulso (Razão de Taxas RT 1,31; IC 95% 1...

Análise de sobrevida de pacientes coinfectados HIV/HCV de um centro de referência em DST/AIDS no município de São Paulo; Survival analysis of HIV/HCV co-infected patients at a STD/AIDS reference center in the city of São Paulo

Alencar, Wong Kuen
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 16/09/2011 Português
Relevância na Pesquisa
36.21%
Introdução: A estimativa de sobrevida de pacientes com HIV/aids aumentou após a terapia antirretroviral de alta potência: no entanto, a mortalidade por doenças hepáticas também cresceu. Objetivos: Estimar a probabilidade acumulada de sobrevida após o diagnóstico de aids entre pacientes coinfectados HIV/HCV e realizar análise exploratória para investigar fatores relacionados à sobrevida desses pacientes. Metodologia: Estudo de coorte não concorrente, utilizando sistemas de Informações: o de Agravos de Notificação, o de informação laboratorial e o de informação da vigilância epidemiológica do Centro de Referência e Treinamento DST/AIDS-SP, de pacientes com aids maiores de 13 anos, acompanhados no ambulatório geral. As variáveis estudadas foram: hepatite C, hepatite B, categoria de exposição, contagem de células T CD4+, faixa etária, escolaridade, cor, sexo e períodos de diagnóstico de aids: 1986 a 1993, 1994 a 1996, 1997 a 2002 e 2003 a 2010. Foi utilizado o estimador de Kaplan-Meier, o modelo de Cox e as estimativas das hazard ratio (HR) com os respectivos intervalos de confiança (IC 95 por cento ). Resultados: De um total de 2.864 pessoas incluídas, com idade mediana de 35 anos, 219 foram a óbito (7...

Análise da sobrevida do paciente e do enxerto de diabéticos submetidos a diferentes modalidades de transplante; Analysis of patient and graft survival of diabetic patients undergoing different modalities of transplantation

Mesquita, Pablo Girardelli Mendonça
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 11/12/2013 Português
Relevância na Pesquisa
36.3%
O diabetes mellitus (DM) é a principal causa de doença renal crônica (DRC) em vários países do mundo. Para pacientes diabéticos com DRC estágio 5 e indicação da terapia renal substitutiva, o transplante (Tx) renal representa uma modalidade terapêutica com técnica bem estabelecida e com excelentes resultados. O transplante simultâneo de rim-pâncreas (TSRP), uma alternativa mais recente praticada em um número mais restrito de centros, apresenta resultados positivos adicionais no controle metabólico, na qualidade de vida e nas complicações crônicas do diabetes. Entretanto, está associado a um risco maior de complicações pós-operatórias e maior número de internações. Tanto o transplante renal quanto o TSRP estão associados a melhor sobrevida do paciente em relação à diálise. A escolha da melhor modalidade de transplante para o paciente diabético com DRC ainda não está clara. O objetivo deste estudo foi analisar os resultados de diferentes modalidades de transplante em pacientes diabéticos com DRC estágio 5, realizados em 3 Centros Brasileiros de Transplante. Assim, analisar a sobrevida do paciente e do enxerto renal após 1, 5 e 8 anos em pacientes DM tipo 1 submetidos a TSRP comparados com transplante renal isolado com doador vivo (DM1-DV) ou transplante de renal isolado com doador falecido (DM1-DF) (Estudo de 3 modalidades de Tx em DM tipo1). Além disso...

Alerta e proteção parental na sobrevivência do câncer do filho; Parental alertness and protection in cancer survival of children

Dias, Patrícia Luciana Moreira
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 25/02/2014 Português
Relevância na Pesquisa
36.21%
Introdução: O número de crianças e adolescentes que sobrevivem ao câncer tem aumentado de maneira significativa nas últimas décadas. A sobrevivência é uma experiência que não se limita àquele que sobreviveu ao câncer, mas engloba também a sua família. Considerando as evidências do impacto que o câncer exerce sobre a vida familiar e sobre o relacionamento entre pais e criança com câncer, este estudo tem como foco famílias de crianças e adolescentes que sobreviveram ao câncer, na perspectiva da parentalidade. Objetivos: Identificar os elementos do processo da parentalidade na sobrevivência do câncer infantojuvenil e apresentar um modelo teórico deste processo que represente a integração desses elementos. Metodologia: Estudo qualitativo, que teve como referenciais teórico e metodológico, respectivamente, o Interacionismo Simbólico e a Teoria Fundamentada nos Dados. Os dados foram coletados por meio de entrevistas com nove casais, pais e mães de crianças e adolescentes que sobreviveram ao câncer infantojuvenil. Resultados: A análise comparativa dos dados permitiu compreender o processo da parentalidade na sobrevivência do câncer revelada pelo modelo teórico ALERTA E PROTEÇÃO PARENTAL NA SOBREVIVÊNCIA DO CÂNCER DO FILHO. O modelo evidencia que os elementos simbólicos essenciais para a construção e o exercício da parentalidade no contexto da sobrevivência do câncer estão estruturados em torno de dois fenômenos: O TEMPO DE LUTA CONTRA O CÂNCER DO FILHO...

Impact of MELD allocation policy on survival outcomes after liver transplantation: a single-center study in northeast Brazil

Batista,Thales Paulo; Sabat,Bernardo David; Melo,Paulo Sérgio V.; Miranda,Luiz Eduardo C.; Fonseca-Neto,Olival Cirilo L.; Amorim,Américo Gusmão; Lacerda,Cláudio Moura
Fonte: Faculdade de Medicina / USP Publicador: Faculdade de Medicina / USP
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2011 Português
Relevância na Pesquisa
36.23%
OBJECTIVE: To analyze the impact of model for end-stage liver disease (MELD) allocation policy on survival outcomes after liver transplantation (LT). INTRODUCTION: Considering that an ideal system of grafts allocation should also ensure improved survival after transplantation, changes in allocation policies need to be evaluated in different contexts as an evolutionary process. METHODS: A retrospective cohort study was carried out among patients who underwent LT at the University of Pernambuco. Two groups of patients transplanted before and after the MELD allocation policy implementation were identified and compared using early postoperative mortality and post-LT survival as end-points. RESULTS: Overall, early postoperative mortality did not significantly differ between cohorts (16.43% vs. 8.14%; p = 0.112). Although at 6 and 36-months the difference between pre-vs. post-MELD survival was only marginally significant (p = 0.066 and p = 0.063; respectively), better short, medium and long-term post-LT survival were observed in the post-MELD period. Subgroups analysis showed special benefits to patients categorized as nonhepatocellular carcinoma (non-HCC) and moderate risk, as determined by MELD score (15-20). DISCUSSION: This study ensured a more robust estimate of how the MELD policy affected post-LT survival outcomes in Brazil and was the first to show significantly better survival after this new policy was implemented. Additionally...

Survival on long-term oxygen therapy in chronic airflow limitation: from evidence to outcomes in the routine clinical setting

Crockett, A.; Cranston, J.; Moss, J.; Alpers, J.
Fonte: Blackwell Publishing Asia Publicador: Blackwell Publishing Asia
Tipo: Artigo de Revista Científica
Publicado em //2001 Português
Relevância na Pesquisa
36.23%
BACKGROUND: Two previous randomized controlled trials (RCT) demonstrated that the administration of long-term oxygen therapy (LTOT) improved survival in selected patients with hypoxic chronic obstructive pulmonary disease (COPD) or chronic airflow limitation (CAL). AIMS: The aim of the present study was to investigate whether the survival of CAL patients prescribed LTOT at Flinders Medical Centre (FMC) was gender and age related, and equivalent to that of the previous RCT. METHODS: A list of patients prescribed domiciliary oxygen therapy for CAL at FMC was generated from Respiratory Unit records and hospital financial records for the supply of this therapy. Survival was compared with that reported for the original RCT, and for Swedish and Belgian COPD patients. Factors influencing survival were studied. RESULTS: Five hundred and five (249 males, 256 females) patients were prescribed LTOT for CAL at FMC during the study period and included in the survival analysis. The patients were elderly with multiple comorbidities. Survival was less than for the control arms of the previous RCT (apart from the Medical Research Council Working Party (MRC) female group) but comparable with recent overseas data. Overall crude survival was 75.1%, 51.3%...

Trends in survival from colonic cancer: the impact of subspecialization

Hoffmann, D.; Moore, J.; Roder, D.
Fonte: BLACKWELL SCIENCE Publicador: BLACKWELL SCIENCE
Tipo: Artigo de Revista Científica
Publicado em //1997 Português
Relevância na Pesquisa
36.22%
BACKGROUND: Data from population-based registries have demonstrated a recent increase in case survival for colonic cancer which has been attributed to earlier diagnosis. The present study was performed to identify time trends in case survival for patients with colonic cancer in a single institution, and to identify factors associated with any such improvement. METHODS: Data regarding 1264 patients with colonic cancer who were diagnosed between January 1981 and December 1995 were obtained from the Royal Adelaide Hospital Cancer Registry. Prognostic factors examined were age, sex, Australian clinicopathologic stage (ACPS), differentiation and year of diagnosis. Survival analyses were performed using the Kaplan-Meier method, and differences between patient subgroups were tested using univariate and multivariate Cox analyses. Patterns of adjuvant therapy were stable throughout the study period. RESULTS: The study group comprised 1264 patients. Key independent predictors of case survival after controlling for covariables were found to be earlier-stage disease (P < 0.001), moderately or well differentiated tumours (P < 0.001), and more recently diagnosed tumours (P = 0.011). Specifically, the 5-year survival rates (+/- SE) increased from 40.3% (+/- 3.2) for 1981-83 to 48.3% (+/- 3.3) for 1984-86 and 51.6% (+/- 2.1) for 1987-95. This increase in case survival was temporally associated with the establishment of a specialty colorectal surgical unit within the Royal Adelaide Hospital. CONCLUSIONS: This study of patients with colonic cancer from a single institution confirms previously observed...

A new approach to the "apparent survival" problem: Estimating true survival rates from mark-recapture studies

Gilroy, J.; Virzi, T.; Boulton, R.; Lockwood, J.
Fonte: Ecological Soc Amer Publicador: Ecological Soc Amer
Tipo: Artigo de Revista Científica
Publicado em //2012 Português
Relevância na Pesquisa
36.23%
Survival estimates generated from live capture-mark-recapture studies may be negatively biased due to the permanent emigration of marked individuals from the study area. In the absence of a robust analytical solution, researchers typically sidestep this problem by simply reporting estimates using the term "apparent survival." Here, we present a hierarchical Bayesian multistate model designed to estimate true survival by accounting for predicted rates of permanent emigration. Initially we use dispersal kernels to generate spatial projections of dispersal probability around each capture location. From these projections, we estimate emigration probability for each marked individual and use the resulting values to generate bias-adjusted survival estimates from individual capture histories. When tested using simulated data sets featuring variable detection probabilities, survival rates, and dispersal patterns, the model consistently eliminated negative biases shown by apparent survival estimates from standard models. When applied to a case study concerning juvenile survival in the endangered Cape Sable Seaside Sparrow (Ammodramus maritimus mirabilis), bias-adjusted survival estimates increased more than twofold above apparent survival estimates. Our approach is applicable to any capture-mark-recapture study design and should be particularly valuable for organisms with dispersive juvenile life stages.; James J. Gilroy...

Experimental investigation of the cell survival in dose cold spot

Sjostedt, S.; Bezak, E.; Marcu, L.
Fonte: Informa Healthcare Publicador: Informa Healthcare
Tipo: Artigo de Revista Científica
Publicado em //2014 Português
Relevância na Pesquisa
36.22%
The aim of this work was to investigate the impact of intercellular contact during radiation exposure on cell survival in regions of reduced dose. Methods. The PC3 human prostate adenocarcinoma cell line was irradiated using a 6 MV x-ray beam to assess clonogenic cell deaths with the specific aim to investigate cell survival in a dose cold spot. Radiation-induced cell survival in a 20% lower dose region, compared to that of cells receiving 100% of the prescribed dose (2 Gy), was assessed for experimental set-ups when under-irradiated cells were either in direct contact with cells receiving 2 Gy or irradiated separately. In addition, the results were compared against non-irradiated controls. Results. A significant (p < 0.001) decrease in cell survival was found when cells, collocated in the same flask, received either 100% or 80% of the prescribed dose (the dose distribution contained a cold spot of 20% lower dose) compared to non-irradiated cells. However, in the experiment in which the entire flask was exposed to only 80% of the prescribed dose, the mean difference in cell survival compared to non-irradiated control was not significant (p > 0.05). This was contrary to a significant decrease (p < 0.001) in survival of cells receiving 100% of the prescribed dose versus the control. Additionally...

Cancer survival for Aboriginal and Torres Strait Islander Australians: a national study of survival rates and excess mortality

Condon, J.R.; Zhang, X.; Baade, P.; Griffiths, K.; Cunningham, J.; Roder, D.M.; Coory, M.; Jelfs, P.L.; Threlfall, T.
Fonte: BioMed Central Publicador: BioMed Central
Tipo: Artigo de Revista Científica
Publicado em //2014 Português
Relevância na Pesquisa
36.26%
BACKGROUND: National cancer survival statistics are available for the total Australian population but not Indigenous Australians, although their cancer mortality rates are known to be higher than those of other Australians. We aimed to validate analysis methods and report cancer survival rates for Indigenous Australians as the basis for regular national reporting. METHODS: We used national cancer registrations data to calculate all-cancer and site-specific relative survival for Indigenous Australians (compared with non-Indigenous Australians) diagnosed in 2001-2005. Because of limited availability of Indigenous life tables, we validated and used cause-specific survival (rather than relative survival) for proportional hazards regression to analyze time trends and regional variation in all-cancer survival between 1991 and 2005. RESULTS: Survival was lower for Indigenous than non-Indigenous Australians for all cancers combined and for many cancer sites. The excess mortality of Indigenous people with cancer was restricted to the first three years after diagnosis, and greatest in the first year. Survival was lower for rural and remote than urban residents; this disparity was much greater for Indigenous people. Survival improved between 1991 and 2005 for non-Indigenous people (mortality decreased by 28%)...

Effekte psychoonkologischer Interventionen auf die Überlebenszeit und die Lebensqualität von PatientInnen unter Stammzelltransplantation; Effects of psycho-oncological interventions on survival time and quality of life for patients undergoing stem cell transplantation

Domann, Ursula
Fonte: Universidade de Tubinga Publicador: Universidade de Tubinga
Tipo: Dissertação
Português
Relevância na Pesquisa
36.22%
Hintergrund: Trotz großer Fortschritte in der Medizin ist die allogene Stammzelltransplantation weiterhin mit vielfältigen transplantationsbedingten physischen und psychischen Problemen verbunden. Die Überlebenszeit, rezidivfreie Zeit und die Lebensqualität sind Themen, die dabei von allgemeinem Interesse sind. Im psychoonkologischen Bereich wurde diese Gruppe von Patientinnen bisher noch nicht dahingehend untersucht, welchen Einfluss psychoonkologische Interventionen auf die Überlebenszeit und die Lebensqualität haben. Patienten und Methode: Es handelte sich um eine prospektive, longitudinale Studie, wobei die PatientInnen des Transplantationszentrums Tübingen einem ABBA-Untersuchungsdesigns zugeordnet wurden (A=Kontrollgruppe, B=Interventionsgruppe). 70 PatientInnen mit allogener Stammzelltransplantation konnten von September 1999 bis Dezember 2001 für die Studie rekrutiert werden. 34 Pat. gehörten der Kontrollgruppe an, die die medizinische Therapie as usual bekamen und 36 Pat. gehörten zur Interventionsgruppe, die zusätzliche psychoonkologische Interventionen (Entspannungsübungen, Imaginationen, supportive und kognitiv-behaviorale Interventionen) erhielten. Medizinische und psychologische (EORTC-QLQ-30) Parameter wurden bei Aufnahme auf Station...

Impact of MELD allocation policy on survival outcomes after liver transplantation: a single-center study in northeast Brazil

Batista, Thales Paulo; Sabat, Bernardo David; Melo, Paulo Sérgio V.; Miranda, Luiz Eduardo C.; Fonseca-Neto, Olival Cirilo L.; Amorim, Américo Gusmão; Lacerda, Cláudio Moura
Fonte: Universidade de São Paulo. Faculdade de Medicina Publicador: Universidade de São Paulo. Faculdade de Medicina
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; ; ; ; ; Formato: application/pdf
Publicado em 01/01/2011 Português
Relevância na Pesquisa
36.23%
OBJECTIVE: To analyze the impact of model for end-stage liver disease (MELD) allocation policy on survival outcomes after liver transplantation (LT). INTRODUCTION: Considering that an ideal system of grafts allocation should also ensure improved survival after transplantation, changes in allocation policies need to be evaluated in different contexts as an evolutionary process. METHODS: A retrospective cohort study was carried out among patients who underwent LT at the University of Pernambuco. Two groups of patients transplanted before and after the MELD allocation policy implementation were identified and compared using early postoperative mortality and post-LT survival as end-points. RESULTS: Overall, early postoperative mortality did not significantly differ between cohorts (16.43% vs. 8.14%; p = 0.112). Although at 6 and 36-months the difference between pre-vs. post-MELD survival was only marginally significant (p = 0.066 and p = 0.063; respectively), better short, medium and long-term post-LT survival were observed in the post-MELD period. Subgroups analysis showed special benefits to patients categorized as nonhepatocellular carcinoma (non-HCC) and moderate risk, as determined by MELD score (15-20). DISCUSSION: This study ensured a more robust estimate of how the MELD policy affected post-LT survival outcomes in Brazil and was the first to show significantly better survival after this new policy was implemented. Additionally...

Acute rejection during the first six-months after transplantation: temporal trends regarding risk factors and effects on graft and patient survival

Costa,Rui; Malheiro,Jorge; Santos,Clara; Fonseca,Isabel; Martins,La Salete; Pedroso,Sofia; Almeida,Manuela; Dias,Leonidio; Castro-Henriques,Antonio; Morgado,Teresa; Cabrita,Antonio
Fonte: Sociedade Portuguesa de Nefrologia Publicador: Sociedade Portuguesa de Nefrologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2014 Português
Relevância na Pesquisa
36.23%
Objective: To determine risk factors for acute rejection in the first 6 months post- transplant and their effect on death-censored graft and patient survival in the 990-1999 and 2000-2009 periods. Patients and Methods: Retrospective analysis of acute rejection episodes was performed separately in two periods: 1990-1999 and 2000-2009. Multivariate logistic regression analysis was performed in order to identify risk factors for acute rejection. Death-censored graft and patient survival comparison between patients with or without acute rejection occurrence was performed by Kaplan-Meier analysis. Multivariate Cox regression analysis identified independent predictors for death-censored graft and patient survival, assuming the following model: acute rejection, patient’s age (< 40 vs. ≥ 40 years) and gender, time on haemodialysis / peritoneal dialysis (< 36 vs. ≥ 36 months), live vs. deceased donor (only after the year 2000), HLA mismatches (0-3 vs. 4-6), PRA (≤ 15 vs. > 15%), number of previous kidney transplants (< 2 vs. ≥ 2), status of hepatitis B/C, donor´s age (< 38 vs. ≥ 38 years) and gender, delayed graft function (DGF), ATG use in induction immunosuppression (IS), MMF or Tacrolimus use in induction / maintenance IS (after 2000). Results: A total of 1299 kidney transplants were analyzed. Acute rejection was more frequently diagnosed in the 1990s (26.2% vs. 11.1%...