Synthesis of sub-5 nm Co-doped SnO2_2 nanoparticles and their structural, microstructural, optical and photocatalytic properties

A swift chemical route to synthesize Co-doped SnO$_2$ nanopowders is described. Pure and highly stable Sn$_{1-x}$Co$_x$O$_{2-\delta}$ (0 $\le$ x $\le$ 0.15) crystalline nanoparticles were synthesized, with mean grain sizes < 5 nm and the dopant element homogeneously distributed in substitutional sites of the SnO$_2$ matrix. The UV-visible diffuse reflectance spectra of the Sn$_{1-x}$Co$_x$O$_{2-\delta}$ samples reveal red shifts, the optical bandgap energies decreasing with increasing Co concentration. The Urbach energies of the samples were calculated and correlated with their bandgap energies. The photocatalytic activity of the Sn$_{1-x}$Co$_x$O$_{2-\delta}$ samples was investigated for the 4-hydroxylbenzoic acid (4-HBA) degradation process. A complete photodegradation of a 10 ppm 4-HBA solution was achieved using 0.02% (w/w) of Sn$_{0.95}$Co$_{0.05}$O$_{2-\delta}$ nanoparticles in 60 min of irradiation.Comment: 29 pages, 2 tables, 10 figure

Modelling competing risks in nephrology research: an example in peritoneal dialysis

BACKGROUND: Modelling competing risks is an essential issue in Nephrology Research. In peritoneal dialysis studies, sometimes inappropriate methods (i.e. Kaplan-Meier method) have been used to estimate probabilities for an event of interest in the presence of competing risks. In this situation a competing risk analysis should be preferable. The objectives of this study are to describe the bias resulting from the application of standard survival analysis to estimate peritonitis-free patient survival and to provide alternative statistical approaches taking competing risks into account. METHODS: The sample comprises patients included in a university hospital peritoneal dialysis program between October 1985 and June 2011 (n = 449). Cumulative incidence function and competing risk regression models based on cause-specific and subdistribution hazards were discussed. RESULTS: The probability of occurrence of the first peritonitis is wrongly overestimated using Kaplan-Meier method. The cause-specific hazard model showed that factors associated with shorter time to first peritonitis were age (>=55 years) and previous treatment (haemodialysis). Taking competing risks into account in the subdistribution hazard model, age remained significant while gender (female) but not previous treatment was identified as a factor associated with a higher probability of first peritonitis event. CONCLUSIONS: In the presence of competing risks outcomes, Kaplan-Meier estimates are biased as they overestimated the probability of the occurrence of an event of interest. Methods which take competing risks into account provide unbiased estimates of cumulative incidence for each specific outcome experienced by patients. Multivariable regression models such as those based on cause-specific hazard and on subdistribution hazard should be used in this competing risk setting

Peritoneal dialysis dropouts in different age and era cohorts: focus on the elderly

Introduction and Aims: Peritoneal dialysis (PD) is an efficient renal replacement therapy (RRT), but still remains underutilized at any age. Clinicians fear the rate of dropouts and lower technique survival, particularly in elderly patients. The authors aimed to explore such outcomes over the past 3 decades, in different age and era cohorts. Methods: Consecutive incident patients starting PD were identified from an ongoing registry-base prospective study of quality assessment. In order to control for an era effect, patients were assigned to 6 cohorts (5 years interval) according to the admission year between 1985 and 2014. Regression models taking competing risks into account were performed to identify potential prognostic factors for death and transfer to haemodialysis (HD) (adjusted for age, gender, diabetes, cohort era, automated peritoneal dialysis (APD) use, and first treatment modality – PD first, PD after HD, PD after renal transplant (RT). Then the patients were studied according to age at enrolment in the programme: A (18 44 years; n = 193); B (45 64 years; n = 176) and C (≥ 65 years old; n = 75). The HD transfer rates using Poisson analysis were evaluated. The incidence of dropout rates was compared at different times and between age groups, focusing particular attention on the elderly. Results: A total of 525 patients were evaluated: 211 male (40.2%), aged 48 ± 15.7 years old, on PD for 23 (IQR 9 – 41.5) months. The major cause of dropout technique was transfer to HD (35.4%), followed by renal transplantation (27.6%) and death (21.7%). The probability of technical failure and renal transplantation at 2 and 5 years was 19.2% and 18.1% and 34.2%; 27.4%, respectively. Probability of death at 2 and 5 years was 12.7%, and 21.8%, respectively. The contemporary cohort was associated with a lower risk of mortality and lower risk of transfer to haemodialysis, with greater access to renal transplantation. The regression model Fine & Gray showed that older age was associated with increased mortality, but was not associated with greater technical failure. Transfer to HD occurred in the elderly at a rate of 11epy/100 patient year (in comparison to 15 and 14 epy/100 patient-year in non-elderly groups A and B, respectively P= 0.33). The proportions of specific causes of technique failure did not change significantly according to age cohort. The dropout rates due to access-related-infection and ultrafiltration failure decreased in the elderly group in the more contemporary cohort, despite the differences were not statistically significant. Conclusions: The dropout by technique failure decreased significantly in the recent decade. Age at admission in peritoneal dialysis did not show to be a compromising factor of the technique survivalIntrodução e Objetivos: A diálise peritoneal (DP) é uma técnica substitutiva da função renal (TSFR) com eficácia semelhante à hemodiálise (HD); no entanto, ainda permanece subutilizada em qualquer idade. Os médicos temem o elevado drop-out da técnica e a sua menor sobrevida, particularmente nos doentes idosos. Os autores pretenderam explorar causas de drop-out e sobrevida da técnica ao longo das últimas três décadas, em diferentes faixas etárias, centrando uma atenção particular no idoso. Métodos: Foram usados dados do registo prospetivo do programa hospitalar de doentes adultos incidentes em DP. Tendo em conta as diferentes épocas, os doentes foram divididos em 6 coortes (5 anos de intervalo) de acordo com o ano de admissão no programa (1985-2014). Usaram-se modelos de regressão tendo em conta a análise de riscos competitivos para identificar potenciais fatores de prognóstico para a morte e transferência para HD (ajustados para a idade, género, diabetes, era, tipo de técnica e primeira modalidade de TSFR). Posteriormente, os doentes foram estudados de acordo com a idade à admissão no programa: A (18 44 anos); B (45 64 anos) e C (≥ 65 anos de idade). Foram avaliadas as taxas de transferência para HD usando a análise de Poisson. As taxas de incidência de drop-out foram comparadas em diferentes épocas e entre os grupos etários, focando particular atenção no doente idoso. Resultados: Foram avaliados 525 pacientes: 211 eram do sexo masculino (40,2%), com idade média de 48 ± 15,7 anos, com follow-up mediano de 23 meses (IQR 9-41,5). A maior causa de drop-out da técnica foi a transferência para HD (35,4%), seguida do transplante renal (27,6%) e de morte (21,7%). A probabilidade de falência técnica e transplantação renal aos 2 e aos 5 anos foi 19,2% e 18,1% e 34,2%; 27,4%, respetivamente. A probabilidade de morte aos 2 e aos 5 anos foi 12,7%, e 21,8%, respetivamente. A coorte mais recente associou-se a menor risco de mortalidade e menor transferência para HD. O modelo de regressão Fine & Gray mostrou que a idade avançada se associou a maior mortalidade, contudo não se associou a maior falência técnica. Nos idosos, a taxa de transferência para HD foi 11,2 episódios/100 doentes-ano (em comparação com 15 e 14 episódios/100 doentes-ano nos grupos A e B, respectivamente, p= 0,33). Não houve diferenças significativas nas causas de transferência para HD entre os diferentes grupos etários. As taxas de drop-out por falência de acessos e por falência de ultrafiltração diminuíram no grupo mais velho e na coorte mais recente, contudo as diferenças não foram estatisticamente significativas entre os grupos. Conclusões: O drop-out por falência técnica diminuiu significativamente na década mais recente. A idade de admissão na diálise peritoneal não mostrou ser um fator de comprometimento da sobrevida da técnic

Hepatocyte growth factor signalizes peritoneal membrane failure in peritoneal dialysis

BACKGROUND: Hepatocyte growth factor (HGF) counteracts peritoneal fibrosis in animal models and in-vitro studies, but no study explored effluent HGF in peritoneal dialysis (PD) patients with ultrafiltration failure (UFF). Our aim was to assess the relationship between effluent HGF with UF profile, free water transport (FWT) and small-solute transport. METHODS: We performed 4-hour, 3.86% PET with additional UF measurement at 60 minutes in 68 PD patients. MTACcreatinine, FWT, small-pore ultrafiltration, and effluent HGF were quantified. RESULTS: Effluent HGF negatively correlated with UF (r=-0.80, p=0.009) and FWT (r=-0.69, p=0.04). Patients with UFF had higher dialysate HGF (103 pg/mL vs 77 pg/mL, p=0.018) and, although not statistically significant, those with FWT compromise had also higher dialysate HGF compared with subgroup of UFF without FWT compromise (104 pg/mL vs 88 pg/mL, p=0.08). FWT≤45% without clinical UFF was documented in some patients who also had increased effluent HGF. CONCLUSIONS: Dialysate HGF concentration is significantly higher among patients with UFF, specially, if FWT is impaired, being a sign of peritoneal membrane deterioration.This study was partially performed with the help of investigations grants from Sociedade Portuguesa de Nefrologia. This work was also supported by UMIB/ICBAS – University of Porto (UP). Multidisciplinary Unit for Biomedical Research (UMIB) is funded by grants from Foundation for Science and Technology (Fcomp-01-0124-FEDER-015896

Effect of hydroxyethyl starch on acute renal injury in a model of hepatic ischemia-reperfusion

BACKGROUND: Hepatic vascular control techniques employed during liver surgery are usually associated with ischemia-reperfusion injury, which could cause acute renal dysfunction. The murine model has been used in the study of this injury. Hydroxyethyl starch has recognized anti-inflammatory properties and improves microcirculation. Third generation hydroxyethyl starches, namely 130/0.4, show a better safety profile than previous molecules. OBJECTIVES: Evaluation of renal injury in a murine model of partial normothermic hepatic ischemia-reperfusion injury and assessment of hydroxyethyl starch 130/0.4 effect on this injury. METHODS: Seventy-two male Wistar rats were randomized into six groups with identical characteristics (n = 12 x 6). In three of them, the ischemia-reperfusion injury groups, we placed a clamp in the vascular pedicle of the median and left liver lobes, inducing hepatic ischemia (70%), and removed the clamp 60 minutes later (IRI + HES and IRI + HS groups, with HES or hypertonic saline (7.5%) administration during reperfusion, respectively, and IRI group, without fluid therapy). The control groups were sham-operated without hepatic ischemia and treated likewise (sham + HES, sham + HS and sham groups). After 120 minutes of reperfusion in the ischemia-reperfusion injury groups and 180 minutes in the controls we drew blood from the aorta artery for creatinine, urea and alanine aminotransferase quantification and removed kidney and liver samples for histopathological analysis. RESULTS: As already published by our group, the partial hepatic ischemia-reperfusion injury model showed liver injury. In the present work, the IRI group had higher creatinine, urea and histopathological score than sham (p < 0.05). Creatinine and urea mean concentrations were significantly lower both in IRI+HES (23.08 µmol/L and 8.38 mmol/L, respectively) and IRI + HS (26.59 µmol/L and 7.82 mmol/L) when compared to IRI (40.101 µmol/L and 11.25 mmol/L). There was no significant difference between IRI + HES and IRI + HS groups (serum markers and histopathology).Conclusion: The hepatic ischemia-reperfusion injury murine model was effective in producing kidney injury. Both the hydroxyethyl starch 130/0.4 and the hypertonic saline protected the kidney in this context and were not harmful for this organ in the controls. Further studies are necessary to assess clinical implications of hydroxyethyl starch 130/0.4 administration in liver surgery

Different kidney function trajectory patterns before dialysis in elderly patients: clinical implications and outcomes

Background. Identifying trajectories of kidney disease progression in chronic kidney disease (CKD) patients may help to deliver better care. We aimed to identify and characterize trajectories of renal function decline in CKD patients and to investigate their association with mortality after dialysis.Methods. This retrospective cohort study included 378 CKD patients who initiated dialysis (aged 65 years and over) between 2009 and 2016. Were considered mixed models using linear quadratic and cubic models to define the trajectories, and we used probabilistic clustering procedures. Patient characteristics and care practices at and before dialysis were examined by multivariable multinomial logistic regression. The association of these trajectories with mortality after dialysis was examined using Cox models.Results. Four distinct groups of eGFR trajectories decline before dialysis were identified: slower decline (18.3%), gradual decline (18.3%), early rapid decline (41.2%), and rapid decline (22.2%). Patients with rapid eGFR decline were more likely to have diabetes, more cognitive impairment, to have been hospitalized before dialysis, and were less likely to have received pre-dialysis care compared to the patients with a slower decline. They had a higher risk of death within the first and fourth year after dialysis initiation, and after being more than 4 years in dialysis.Conclusions. There are different patterns of eGFR trajectories before dialysis initiation in the elderly, that may help to identify those who are more likely to experience an accelerated decline in kidney function, with impact on pre ESKD care and in the mortality risk after dialysis

Biomarkers and Imaging Findings of Anderson-Fabry Disease-What We Know Now

Anderson-Fabry disease (AFD) is an X-linked lysosomal storage disorder, caused by deficiency or absence of the alpha-galactosidase A activity, with a consequent glycosphingolipid accumulation. Biomarkers and imaging findings may be useful for diagnosis, identification of an organ involvement, therapy monitoring and prognosis. The aim of this article is to review the current available literature on biomarkers and imaging findings of AFD patients. An extensive bibliographic review from PubMed, Medline and Clinical Key databases was performed by a group of experts from nephrology, neurology, genetics, cardiology and internal medicine, aiming for consensus. Lyso-GB3 is a valuable biomarker to establish the diagnosis. Proteinuria and creatinine are the most valuable to detect renal damage. Troponin I and high-sensitivity assays for cardiac troponin T can identify patients with cardiac lesions, but new techniques of cardiac imaging are essential to detect incipient damage. Specific cerebrovascular imaging findings are present in AFD patients. Techniques as metabolomics and proteomics have been developed in order to find an AFD fingerprint. Lyso-GB3 is important for evaluating the pathogenic mutations and monitoring the response to treatment. Many biomarkers can detect renal, cardiac and cerebrovascular involvement, but none of these have proved to be important to monitoring the response to treatment. Imaging features are preferred in order to find cardiac and cerebrovascular compromise in AFD patients.info:eu-repo/semantics/publishedVersio

Pericardial and pleural effusions associated with sirolimus and discussion of possible mechanisms

Sirolimus, a mammalian target of rapamycin inhibitor, is an increasingly used immunosuppressant in solid-organ transplantation. There are an increasing number of reports of unusual oedematous adverse effects associated with this drug, including lymphoedema, ascites and pleural effusions, and a few reports of pericardial effusions. No pathophysiological explanation for these phenomena has been disclosed. We report a 33-year-old sirolimus-treated kidney transplant recipient with chronic pericardial and pleural effusions identified nine years after transplantation. He was initially treated for a presumed tuberculous pericarditis, even though cultures for Mycobacterium tuberculosis were negative. After 12 months of antitubercular therapy, visceral effusions persisted. Pericardial effusion was drained and stabilised. After exclusion of other causes, sirolimus toxicity was considered the most likely cause. Two months after discontinuation of sirolimus, visceraleffusions disappeared. Interaction of mammalian target of rapamycin inhibitors with mediators of lymphangiogenesis may be a common link in oedematous states associated with sirolimus

O inquérito à Arquitectura Regional Portuguesa e a antropologia: Um caso de transversalidade metodológica

A presente comunicação expõe os resultados de uma investigação em curso conduzida pelas autoras desta comunicação, cujas primeiras abordagens permitiram identificar no Inquérito da Arquitectura Regional Portuguesa uma importante fonte de informação para o aprofundamento do estudo da morfologia urbana em Portugal (MaratMendes e Cabrita, 2015). Assim, partindo dos primeiros resultados dessa investigação, que permitiram identificar a realização de uma sistematização de carácter tipo-morfológico em Portugal, nos finais da primeira metade do século XX, conduzida por Arquitectos Portugueses que participaram na realização do Inquérito atrás referido, através de um confronto com as abordagens morfológicas em uso pelos geógrafos portugueses à época, e identificadas pelas autoras desta comunicação, torna-se agora oportuno aferir que metodologias foram utilizadas pelos Arquitectos, bem como quais as suas eventuais partilhas com métodos conduzidos por outras áreas disciplinares, nomeadamente a Antropologia. No sentido de responder ao objetivo atrás exposto, esta comunicação expõe os resultados de um estudo comparativo das abordagens metodológicas conduzidas por Arquitectos e Antropólogos nas suas análises a um território específico, cujo interesse partilharam durante um mesmo período temporal. O território em apreço refere-se à aldeia de Rio de Onor e aldeias circundantes, que se localiza no noroeste de Portugal. Especificamente, na região identificada como Zona 2 do Inquérito da Arquitectura Regional Portuguesa. O confronto da abordagem metodológica identificada para os Arquitectos e Antropólogos, contemporâneos à realização do Inquérito, leva-nos a concluir pela existência de uma partilha de metodologias que nos propomos aqui a identificar, e que incluem alguns denominadores comuns, nomeadamente a observação directa, a utilização de dados de outras disciplinas, a reflexão e sistematização e a incidência na obra colectiva. Julgamos igualmente importante reflectir sobre o facto de a abordagem metodológica atrás identificada, para os Arquitectos da Zona 2 do Inquérito ter sido central na preparação das soluções propositivas apresentadas por alguns desses arquitectos ao 10º Congresso dos CIAM, em 1956. Configura-se assim a existência de uma transversalidade metodológica, praticada pelos Arquitectos, comum às abordagens dos Antropólogos, contudo vocacionada para aspectos propositivos do projecto; procurando responder por um lado à contemporaneidade dos problemas colocados e com conhecimento das condições locais, nas vertentes do ambiente físico e humano, que também hoje constituem questões prementes na prática profissional de todos os agentes da intervenção na cidade e no território, nomeadamente os arquitectos.info:eu-repo/semantics/publishedVersio