External quality assessment providers' services appear to more impact the immunohaematology performance of laboratories than national regulatory and economic conditions.

OBJECTIVES: Medical laboratories may, at their own discretion, exceed but not undercut regulatory quality requirements. Available economic resources, however, may drive or hinder eagerness to exceed minimum requirements. Depending on the respective scopes of regulatory and economic framework conditions, differing levels of quality efforts to safeguard laboratory performance can be anticipated. However, this has not yet been investigated. METHODS: Immunohaematology external quality assessment (EQA) results collected by 26 EQA providers from their participant laboratories in 73 countries from 2004 to 2019 were evaluated. Error rates were aggregated in groups according to the respective national regulatory and economic framework conditions, to whether or not expert advice was provided in case of incorrect results, and the frequency of EQA samples. RESULTS: These representative data indicate no association between national regulatory (mandatory participation in EQA, monitoring of performance of individual laboratories by authorities, financial consequences of incorrect results) and economic (level of national income, share of national health expenditure) conditions to the quality performance of medical laboratories in immunohaematology. However, EQA providers' support for laboratories in the event of incorrect results appear to be associated with lower error rates, but a high EQA sample frequency with higher error rates. CONCLUSIONS: Further research into the impact of introducing or changing services of EQA providers is needed to confirm the results found in this first of its kind study.

Flavonoids and immune function in human: a systematic review.

Flavonoids, through a modulation of immune function, have been suggested to be involved in the role played by plant foods in disease prevention. We performed a systematic search in the MEDLINE database to review the effect of flavonoid-rich foods and flavonoids supplements on immune function. A total of 58 studies, were identified as suitable: 41 addressed in vivo proinflammatory cytokines and 15 measured ex vivo markers of immune function. According to our findings and on the basis of single food items, the number of studies in humans is limited and, for galenic supplements, only quercetin has been investigated. More evidences are needed to clarify the role of flavonoids as modulator of immune function in humans.

Effect of plant foods and beverages on plasma non-enzymatic antioxidant capacity in human subjects: a meta-analysis.

Non-enzymatic antioxidant capacity (NEAC) represents a sensitive biomarker measuring the in vivo antioxidant potential of vegetable foods. To evaluate the effectiveness of plant-derived foods and beverages on the plasma non-enzymatic antioxidant system, we analysed all literature published upto May 2010. Data were extracted by two authors independently, and the effect size was summarised using standardised mean differences by a random-effects model. For the analysis, eighty-eight studies were included, reporting a total number of 122 interventions and involving 2890 subjects. There was overall evidence of the effectiveness of fruit, vegetables, dietary patterns based on plant foods, red wine and tea in increasing plasma NEAC. No changes were found for chocolate and fruit juices. We observed an overall effect size three times higher in subjects with risk factors when compared with healthy subjects. Total radical-trapping antioxidant parameter, oxygen radical absorbance capacity and ferric-reducing antioxidant power methods showed a similar increase in plasma NEAC following dietary supplementation, whereas Trolox equivalent antioxidant capacity did not respond to dietary supplementation. Data from the present meta-analysis show that plant-derived foods represent an effective strategy to enhance an endogenous antioxidant network in humans. This is particularly evident in the presence of oxidative stress-related risk factors.

Functional foods and nutraceuticals as therapeutic tools for the treatment of diet-related diseases.

In Western societies, the incidence of diet-related diseases is progressively increasing due to greater availability of hypercaloric food and a sedentary lifestyle. Obesity, diabetes, atherosclerosis, and neurodegeneration are major diet-related pathologies that share a common pathogenic denominator of low-grade inflammation. Functional foods and nutraceuticals may represent a novel therapeutic approach to prevent or attenuate diet-related disease in view of their ability to exert anti-inflammatory responses. In particular, activation of intestinal T regulatory cells and homeostatic regulation of the gut microbiota have the potential to reduce low-grade inflammation in diet-related diseases. In this review, clinical applications of polyphenol-rich functional foods and nutraceuticals in postprandial inflammation, obesity, and ageing will be discussed. We have placed special emphasis on polyphenols since they are broadly distributed in plants.

The Role of polyphenols in the modulation of plasma Non-Enzymatic Antioxidant Capacity (NEAC).

Dietary polyphenols have been shown to scavenge free radicals, modulating cellular redox transcription factors in different in vitro and ex vivo models. Dietary intervention studies have shown that consumption of plant foods modulates plasma Non-Enzymatic Antioxidant Capacity (NEAC), a biomarker of the endogenous antioxidant network, in human subjects. However, the identification of the molecules responsible for this effect are yet to be obtained and evidences of an antioxidant in vivo action of polyphenols are conflicting. There is a clear discrepancy between polyphenols (PP) concentration in body fluids and the extent of increase of plasma NEAC. The low degree of absorption and the extensive metabolism of PP within the body have raised questions about their contribution to the endogenous antioxidant network. This work will discuss the role of polyphenols from galenic preparation, food extracts, and selected dietary sources as modulators of plasma NEAC in humans.

Sequence motifs in MADS transcription factors responsible for specificity and diversification of protein-protein interaction.

Protein sequences encompass tertiary structures and contain information about specific molecular interactions, which in turn determine biological functions of proteins. Knowledge about how protein sequences define interaction specificity is largely missing, in particular for paralogous protein families with high sequence similarity, such as the plant MADS domain transcription factor family. In comparison to the situation in mammalian species, this important family of transcription regulators has expanded enormously in plant species and contains over 100 members in the model plant species Arabidopsis thaliana. Here, we provide insight into the mechanisms that determine protein-protein interaction specificity for the Arabidopsis MADS domain transcription factor family, using an integrated computational and experimental approach. Plant MADS proteins have highly similar amino acid sequences, but their dimerization patterns vary substantially. Our computational analysis uncovered small sequence regions that explain observed differences in dimerization patterns with reasonable accuracy. Furthermore, we show the usefulness of the method for prediction of MADS domain transcription factor interaction networks in other plant species. Introduction of mutations in the predicted interaction motifs demonstrated that single amino acid mutations can have a large effect and lead to loss or gain of specific interactions. In addition, various performed bioinformatics analyses shed light on the way evolution has shaped MADS domain transcription factor interaction specificity. Identified protein-protein interaction motifs appeared to be strongly conserved among orthologs, indicating their evolutionary importance. We also provide evidence that mutations in these motifs can be a source for sub- or neo-functionalization. The analyses presented here take us a step forward in understanding protein-protein interactions and the interplay between protein sequences and network evolution.

Prevention of postprandial metabolic stress in humans: role of fruit-derived products.

The consumption of unbalanced meals, consisting of foods rich in lipids and/or carbohydrates and calories, has been associated to a postprandial metabolic stress that involves the increase of the production of free radicals and proinflammatory markers. Growing evidence suggest that dietary polyphenols contained in fruit-derived products, such as fruit juices, are involved in the role played by plant foods in disease prevention. Their association to a calorie-dense meal may help to attenuate the onset of postprandial metabolic and inflammatory stress. The available evidence in the literature investigating the effects of polyphenols rich fruit juices on the modulation of postprandial-induced metabolic stress in humans will be presented and discussed.

Oxidative stress in atherosclerosis development: the central role of LDL and oxidative burst.

The involvement of both oxidative stress and hyperlipaemia in atherosclerosis development is well established. Oxidative burst is an innate immune response to infection, the latter being associated also with marked changes in lipid and lipoprotein metabolism, aimed to neutralize endotoxin toxic effects. On the other hand, lipid overload may increase lipopolysaccharide circulating levels and oxidative stress. Whilst these changes may be beneficial from the perspective of host defense, if they become chronic, they likely increase the risk of atherosclerosis. In particular, oxidation of lipoproteins, resulting from an imbalance of the pro- and antioxidant equilibrium, is involved in the pathologic process of atherosclerosis, changing cellular functions. Lipid oxidation, induced by leukocytes derived reactive oxygen species, can amplify foam cell formation through oxidized low density lipoproteins LDL (oxLDL) formation and uptake. The main enzymes, operating during oxidative burst, involved in LDL oxidation are NADPH oxidase and myeloperoxidase. In vitro studies have shown that oxLDL are able to induce many proatherogenic processes, including modulation of oxidative burst. OxLDL may also induce maturation of dendritic cells and regulate the shift from classical (M1) to alternative (M2) macrophage activation and from T helper 1 to T helper 2 response, suggesting that these could act as a bridge between innate and adaptative immunity, both involved in plaque development. Understanding the relationship between oxLDL and leukocyte oxidative burst helps to explain the involvement of innate immune responses in the early phases of atherosclerosis. The present review focuses on this interplay.

Lymphocytes as internal standard in oxidative burst analysis by cytometry: a new data analysis approach.

We propose a new data analysis approach for reactive oxygen species detection using Dihydrorhodamine 123 in blood monocytes and neutrophils. This approach, based on data transformation using lymphocytes as internal standard, allows to appreciate free radical production by monocytes also without Phorbol 12-myristate 13-acetate (PMA) activation. In addition, this method is sensitive to differences in healthy subjects due to sub-pathological conditions, such as hypercholesterolemia.

Predicting the impact of alternative splicing on plant MADS domain protein function.

Several genome-wide studies demonstrated that alternative splicing (AS) significantly increases the transcriptome complexity in plants. However, the impact of AS on the functional diversity of proteins is difficult to assess using genome-wide approaches. The availability of detailed sequence annotations for specific genes and gene families allows for a more detailed assessment of the potential effect of AS on their function. One example is the plant MADS-domain transcription factor family, members of which interact to form protein complexes that function in transcription regulation. Here, we perform an in silico analysis of the potential impact of AS on the protein-protein interaction capabilities of MIKC-type MADS-domain proteins. We first confirmed the expression of transcript isoforms resulting from predicted AS events. Expressed transcript isoforms were considered functional if they were likely to be translated and if their corresponding AS events either had an effect on predicted dimerisation motifs or occurred in regions known to be involved in multimeric complex formation, or otherwise, if their effect was conserved in different species. Nine out of twelve MIKC MADS-box genes predicted to produce multiple protein isoforms harbored putative functional AS events according to those criteria. AS events with conserved effects were only found at the borders of or within the K-box domain. We illustrate how AS can contribute to the evolution of interaction networks through an example of selective inclusion of a recently evolved interaction motif in the MADS AFFECTING FLOWERING1-3 (MAF1-3) subclade. Furthermore, we demonstrate the potential effect of an AS event in SHORT VEGETATIVE PHASE (SVP), resulting in the deletion of a short sequence stretch including a predicted interaction motif, by overexpression of the fully spliced and the alternatively spliced SVP transcripts. For most of the AS events we were able to formulate hypotheses about the potential impact on the interaction capabilities of the encoded MIKC proteins.

Antioxidant properties of 4-methylcoumarins in in vitro cell-free systems.

4-methylcoumarins that possess two hydroxyl groups ortho to each other in the benzenoid ring have shown to have excellent antioxidant and radical-scavenging properties in different experimental models. Furthermore, they cannot be metabolized by the liver P450 monoxygenases and thus cannot form 3,4-coumarin epoxides, which are believed to be mutagenic. Herein, we present a study on the structure activity relationship of eight synthetic 4-methylcoumarins, carried out by employing a series of different chemical cell-free tests. These compounds were tested by means of three assays involving one redox reaction with the oxidant (DPPH assay, ABTS.+ assay and FRAP). Other assays were employed to evaluate the antioxidant properties of the coumarins under investigation against NO, O2.- and HClO, which are some of the major reactive oxygen and nitrogen species causing damage in the human body. Finally, we have measured the protective capacity of these coumarins against the oxidative damage in a simple biomimetic model of phospholipid membranes. Our results confirm the good antioxidant activity of the 7,8-hydroxy-4-methylcoumarins. In general, their activity is not significantly affected by the introduction of an ethoxycarbonylmethyl or an ethoxycarbonylethyl moiety at the C3 position. A discrete antioxidant activity is retained also by the 7,8-diacetoxy-4-methylcoumarins, although they are less efficient than the corresponding 7,8-dihydroxy compounds. Furthermore, as demonstrated in the brine shrimp toxicity test, none of the tested coumarins significantly affect the larvae viability. Two of the 4-methylcoumarins (7,8-dihydroxy-4-methylcoumarin and 7,8-dihydroxy-3-ethoxycarbonylethyl-4-methylcoumarin), very interestingly, showed strong scavenging activities against the superoxide anion and were also very effective in protecting the lipid bilayer against peroxidation. On the basis of these findings, these 4-methylcoumarins may be considered as potential therapeutic candidates for pathological conditions characterized by free radical overproduction.