Clinical implications of anti-HLA antibodies testing in kidney transplantation

Alloantibodies against donor human leukocyte antigens (HLA), termed as donor‑specific antibodies (DSA), are one of the most important factors for both early and late kidney allograft dysfunction. In the past, these antibodies were mainly detected through cell‑based crossmatch tests. Recently, new techniques such as solid phase immunoassays (SPI) have revealed these antibodies in patient sera with a high degree of detail, previously unimaginable. They have allowed us to accurately determine recipients’ allosensitization status, improve pre‑transplant risk assessment with a potential donor and post‑transplant alloimmune monitoring. However, the high sensitivity of these new assays has also created areas of uncertainty about their clinical impact. In the pre‑transplant setting, the presence of preformed DSA has been associated with an increased risk of antibody‑mediated rejection (AMR) and subsequent allograft loss. Nevertheless, several studies have shown that not all DSA are deleterious. Hence, understanding the clinical correlations of DSA characteristics, namely strength, HLA class, complement‑fixing ability or IgG subclasses, is paramount for an adequate stratification of the immunological risk at transplant. Furthermore, given that the number of allosensitized patients on waiting lists is increasing, the added information from these new SPI is essential to improve their chance of being transplanted with an admissible immunological risk. After transplantation, the appearance of de novo DSA (dnDSA) has also been associated with a deleterious effect on kidney allograft survival. Moreover, it has been acknowledged that a majority of late allograft failures are caused by alloantibody‑driven injury. The current challenges, in this setting, are determining cost‑effective DSA screening protocols and understanding which patients could benefit from specific interventions. Furthermore, although therapeutic strategies to control antibody‑induced damage remain limited, the longitudinal surveillance of dnDSA emergence and the clinical correlations of their characteristics will play a crucial role in the improvement of late kidney allograft survival.info:eu-repo/semantics/publishedVersio

Control and comparison of the antioxidant capacity of beers

The purpose of the present work is to determine the antioxidant capacity (AC) of 27 commercial beers. The AC indicates the degree of protection of a certain organism against oxidative damage provoked by reactive oxygen and nitrogen species. Assays were carried out by the following methods: (i) total radical trapping antioxidant parameter (TRAP); (ii) trolox equivalent antioxidant capacity (TEAC); (iii) trolox equivalent antioxidant capacity (DPPH); (iv) ferric-ion reducing antioxidant parameter (FRAP); (v) cupric reducing antioxidant capacity (CUPRAC); (vi) oxygen radical absorbance capacity (ORAC). Ascorbic acid (AA), gallic acid (GA) and trolox (TR) were used as standards. All beers showed antioxidant power, but a wide range of ACs was observed. The effect of several factors upon these differences was studied. Statistical differences were found between ACs of beers of different colours. ORAC method provided always higher experimental ACs, of significant statistical differences to other assays

Impacto da sensibilização anti -MICA pré -transplante na rejeição e sobrevida do enxerto

Background: Evidence supporting deleterious effect of preformed major histocompatibility class I chain-related A (MICA) antibodies in rejection incidence and graft survival is still unclear. Methods: Retrospective analysis of 554 kidney transplanted patients. Comparison between positive or negative for MICA antibodies patients was performed to characterize sensitizing triggers. Further classification according to pre-transplant flow cytometry-recorded anti–MICA and/or anti-human leukocyte antigen (HLA) antibodies was made to determine first year rejection incidence and graft survival. Multivariate analysis was applied to determine predictors for acute rejection. Results: Pre-formed anti-MICA antibodies were detected in 41 patients (7.4%). HLA sensitization, blood transfusions and pregnancies were frequently found in anti-MICA+ patients but only pre-formed anti-HLA class I antibodies showed independent association (OR 2.67, p= 0.02). Comparing to MICA-/HLA–, MICA-/HLA+ group presented significantly lower first year rejection-free survival (78.6% vs. 89.3%, p< 0.01), mostly occurred in the first six months, while no difference was found in MICA+/HLA– (88.9% vs. 89.3%, p= ns). MICA-/HLA+ showed independent impact in rejection (OR 2.09, p= 0.03), while no evidence was found in MICA+/HLA- (OR 1.08, p= ns). At 4 years, MICA-/HLA+ group presented lower graft survival (85.8% vs. 95.3%, p= 0.03). Again, no difference was found in MICA+/HLA- group (95.1% vs. 95.3%, p= ns). Conclusion: Our results do not support HLA-independent deleterious pathogenic role of pre-formed MICA antibodies on first year rejection incidence and graft survival.Introdução: O efeito deletério dos anticorpos para antigénios MICA (major histocompatibility class I chain-related A) na incidência de rejeição aguda e sobrevida do enxerto ainda não está consensualmente estabelecido. Metódos: Estudo retrospetivo de 554 transplantados renais. A análise comparativa entre doentes positivos e negativos para anticorpos anti-MICA pré-formados foi realizada para avaliar eventos sensibilizadores. A incidência de rejeição aguda no primeiro ano pós transplante renal e a sobrevida do enxerto renal foram determinadas consoante o resultado da citometria de fluxo pré-transplante para anticorpos anti-MICA e/ou anti- HLA (anti-human leukocyte antigen). Aplicou-se um modelo de análise multivariada para identificação de preditores independentes para rejeição aguda. Resultados: Foram identificados 41 doentes (7.4%) com anticorpos anti-MICA pré formados. A sensibilização para HLA, as transfusões sanguíneas e gestações prévias foram mais frequentes nos doentes MICA + mas apenas a presença de anticorpos anti-HLA classe I apresentou uma associação independente (OR 2.67, p= 0.02). Comparativamente ao grupo MICA-/HLA–, o grupo MICA-/HLA+ apresentou menor sobrevida livre de rejeição ao 1º ano (78.6% vs. 89.3%, p< 0.01), maioritariamente ocorrida nos primeiros seis meses, enquanto que nenhuma diferença foi encontrada com o grupo MICA+/HLA– (88.9% vs. 89.3%, p= ns). Apenas o status MICA-/HLA+ teve impacto independente na incidência de rejeição (OR 2.09, p= 0.03), ao contrário do status MICA+/HLA- (OR 1.08, p= ns). O grupo MICA-/HLA+ apresentou menor sobrevida do enxerto censurada para a morte aos 4 anos (85.8% vs. 95.3%, p= 0.03), não se verificando diferenças no grupo MICA+/HLA- (95.1% vs. 95.3%, p= ns). Conclusão: Os nossos resultados não suportam um efeito deletério dos anticorpos pré-formados para MICA, independente da sensibilização HLA, na incidência de rejeição aguda no 1º ano pós transplante e na sobrevida do enxerto

Implications for patients waiting for a kidney transplant of using the calculated panel reactive antibody (cPRA)

Introduction: Kidney transplant improves survival even in highly‑sensitized (HS) patients. To overcome their disadvantage in accessing transplantation, those with high Complement Dependent Cytotoxic PRA (CDC‑PRA) receive additional points during allocation. Whether this strategy reaches all HS patients and how long they wait for a transplant is largely undetermined. Methods: Patients on our unit’s active wait‑list for kidney transplantation in the year 2014 were analyzed. CDC‑PRA and calculated PRA (cPRA) were recorded. To obtain cPRA, antibodies in the last serum available specific for HLA‑A, ‑B or –DR with an intensity > 1000 MFI were considered. Results: The cPRA values in the population (N=551) were 0% (N=312), 1‑79% (N=118) and ≥ 80% (22%; N=121). Among these groups, the proportion of women (29.5, 55.9 and 61.2%, P 50%. Moreover, only 30% of HS by cPRA patients received the extra points designed to improve their transplantability. We consider that both CDC‑PRA and cPRA should be taken into account when defining HS status.info:eu-repo/semantics/publishedVersio

Capacidade antioxidante de cervejas comerciais

Mestrado em Engenharia QuímicaO estudo da capacidade antioxidante (CA) de cervejas consistiu na determinação e avaliação da CA de cervejas comerciais, disponíveis no mercado nacional. A CA indica o grau de protecção conferido ao organismo relativamente a danos oxidativos radicalares envolvidos em processos degenerativos. A CA foi determinada pelos métodos (i) Total radical trapping antioxidant parameter (TRAP); (ii) Trolox equivalent antioxidant capacity (TEAC); (iii) Trolox equivalent antioxidant capacity (DPPH); (iv) Ferric ion reducing antioxidant parameter (FRAP); (v) Cupric reducing antioxidant capacity (CUPRAC); (vi) Oxygen radical absorbance capacity (ORAC). Estes métodos são ópticos e baseiam-se na inibição de radicais livres em solução. Os valores de CA foram calculados relativamente aos compostos ácido ascórbico (AA), ácido gálico (AG) e o trolox (TR). No sentido de esclarecer o efeito de alguns factores na CA das várias amostras de cerveja procedeu-se à análise estatística dos resultados com base no teste ANOVA (analysis of variance). Os factores considerados neste estudo foram: método de análise, composto padrão, marca comercial, tipo, origem, corantes, aromas, antioxidantes, edulcorantes, teor de álcool, cor, sumo e outros aditivos. O teste ANOVA sugeriu a existência de diferenças estatisticamente significativas entre as marcas nos métodos FRAP (para o padrão AG) e no método ORAC. Relativamente ao teor de álcool, somente o método ORAC, para os padrões AG e TR, sugeriu existirem dois subgrupos diferentes. Todos os métodos indicaram diferenças estatisticamente significativas entre os vários grupos de cores da cerveja. No estudo relativo ao efeito do método verificou-se que, para todos os padrões, o método ORAC apresentou diferenças estatisticamente significativas dos restantes, tendo valores de CA muito superiores aos dos restantes métodos usados. No efeito dos padrões concluiu-se que, para todos os métodos, existiam diferenças estatisticamente significativas entre os vários padrões. No método TRAP e CUPRAC todos os padrões se comportaram de forma distinta, nos métodos TEAC e FRAP o padrão AG apresentou CA inferiores aos restantes, pertencendo a um subgrupo diferente. O método DPPH sugeriu que o AG produzia valores de CA superiores aos dos demais padrões. O método ORAC registou um comportamento semelhante, mas para o padrão TR.The antioxidant capacity (CA) of beers was studied by means of its determination and evaluation in commercial beers, available in national market. The CA indicates the degree of protection of a certain organism against the radical oxidative damage, correlated to degenerative diseases. The CA was determinate several methods, such as (i) Total radical trapping antioxidant parameter (TRAP); (ii) Trolox equivalent antioxidant capacity (TEAC); (iii) Trolox equivalent antioxidant capacity (DPPH); (iv) Ferric ion reducing antioxidant parameter (FRAP); (v) Cupric reducing antioxidant capacity (CUPRAC); (vi) Oxygen radical absorbance capacity (ORAC). These are optical methods based in the inhibition of free radicals in aqueous solution. Ascorbic acid (AA), Gallic acid (AG) and Trolox (TR) were used as standards. The effect of some factors upon the observed CA was studied by ANOVA statistical analyses (analysis of variance). Method, standard, commercial brand, kind of fermentation (ale or lager), origin, colorants, flavors, antioxidants, sweeteners, alcohol, color, juice and other additives, were the factors under evaluation. The ANOVA test suggested statistical differences between commercial brands for FRAP (for the standard AG) and ORAC methods. With regard to alcohol level, only ORAC method (standards AG e TR) suggested significant statistical differences between the observed groups. All methods pointed out statistical differences within the different color groups of beers. Evaluation of the effect of method upon CA indicated that ORAC provided higher experimental CA values, of significant statistical differences to other methods. With regard to the effect of standards the observed results depend on the experimental method. TRAP and CUPRAC point out statistical differences within all standards. TEAC and FRAP suggested lower CA for AG. On the contrary, DPPH produced higher CA for AG standard. ORAC method showed statistical differences and higher CA when TR was used as standard

Yeast metabolic state identification using micro-fiber optics spectroscopy

Saccharomyces cerevisiae morphology is known to be dependent on the cell physiological state and environmental conditions. On their environment, wild yeasts tend to form complex colonies architectures, such as stress response and pseudohyphal filaments morphologies, far away from the ones found inside bioreactors, where the regular cell cycle is observed under controlled conditions (e.g. budding and flocculating colonies). In this work we explore the feasibility of using micro-fiber optics spectroscopy to classify Saccharomyces cerevisiae S288C colony structures in YPD media, under different growth conditions, such as: i) no alcohol; ii) 1 % (v/v) Ethanol; iii) 1 % (v/v) 1-butanol; iv) 1 % (v/v) Isopropanol; v) 1 % (v/v) Tert-Amyl alcohol (2 Methyl-2-butanol); vi) 0,2 % (v/v) 2-Furaldehyde; vii) 5 % (w/v) 5 (Hydroxymethyl)-furfural; and viii) 1 % (w/v) (-)-Adenosine3', 5'cyclic monophosphate. The microscopy system includes a hyperspectral camera apparatus and a micro fiber (sustained by micro manipulator) optics system for spectroscopy. Results show that micro fiber optics system spectroscopy has the potential for yeasts metabolic state identification once the spectral signatures of colonies differs from each others. This technique associated with others physico-chemical information can benefit the creation of an information system capable of providing extremely detailed information about yeast metabolic state that will aid both scientists and engineers to study and develop new biotechnological products.The author J.S. Silva tanks to the Fundacao para a Ciencia e Tecnologia for the PhD grant SFRH/BD/48616/2008. Paula Tafulo acknowledges the support of FCT, fellowship SFRH/BD/68924/2010. Part of this research was funded by the project PTDC/BIO/69310/2006.info:eu-repo/semantics/publishedVersio