Sequenom MassARRAY approach in the arrhythmogenic right ventricular cardiomyopathy post-mortem setting: clinical and forensic implications

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a rare cardiac disease characterized by myocardial fibrofatty replacement, which can lead to sudden death. Previous studies have described a reduction of plakoglobin (PKG) protein at the level of intercalated disks as the hallmark of ARVC. The main objective of this study was to investigate the involvement of desmosome mutations in the histological phenotype of ARVC. We performed a genetic analysis of ARVC cases, and histological characterization of ARVC heart tissue samples. We genetically analyzed 48 ARVC cases distributed into two groups: 42 human tissue heart samples with conclusive diagnoses of ARVC after post-mortem examination; and six DNA samples from peripheral blood of living patients who were clinically diagnosed. Sequenom MassARRAY analysis revealed three ARVC-associated variants in three patients in 42 tissue samples (7.14 %). Three individuals carried one single pathogenic mutation, p.R811S _PKP2, p.S824L_DSC2, and p.T526M_PKP2 in postmortem samples. In the living patients group, Sequenom MassARRAY revealed no mutation, however, later Sanger sequencing analysis identified three ARVC mutations in 2/6 patients not included in the Sequenom design. In post-mortem tissue samples we performed immunohistochemical labeling for desmosomal proteins and Connexin 43. This study revealed that PKP2 carriers present either absent or clearly reduced PKG immunolabeling, while the DSC2 carrier showed PKG immunolabeling similar to control samples. Immunolabeling for Cx43 did not show any differences compared to controls. The present Sequenom MassARRAY design is a useful tool for post-mortem genetic diagnosis of ARVC. Plakoglobin reduction occurs at intercalated disks, while other desmosome proteins and Cx43 remain unaltered.

Towards light-mediated sensing of bacterial comfort

Bacterial comfort is central to biotechnological applications. Here, we report the characterization of different sensoring systems, the first step within a broader synthetic biology-inspired light-mediated strategy to determine Escherichia coli perception of environmental factors critical to bacterial performance. We did so by directly 'asking' bacterial cultures with light-encoded questions corresponding to the excitation wavelength of fluorescent proteins placed under the control of environment-sensitive promoters. We built four genetic constructions with fluorescent proteins responding to glucose, temperature, oxygen and nitrogen; and a fifth construction allowing UV-induced expression of heterologous genes. Our engineered strains proved able to give feedback in response to key environmental factors and to express heterologous proteins upon light induction. This light-based dialoguing strategy reported here is the first effort towards developing a human-bacteria interphase with both fundamental and applied implications.

SIGNIFICANCE AND IMPACT OF THE STUDY

The results we present here are at the core of a larger synthetic biology research effort aiming at establishing a dialogue with bacteria. The framework is to convert the human voice into electric pulses, these into light pulses exciting bacterial fluorescent proteins, and convert light-emission back into electric pulses, which will be finally transformed into synthetic voice messages. We report here the first results of the project, in the form of light-based determination of key parameters for bacterial comfort. The ultimate goal of this strategy is to combine different engineered populations to have a combined feedback from the pool.

A computational knowledge-based model for emulating human performance in the Iowa Gambling Task

A new computational knowledge-based model for emulating human performance in decision making tasks is proposed. This model is mainly based on the knowledge acquired through past experience, the knowledge extracted from the environment and the relationships between the concepts that represent these two kinds of knowledge. The proposed model divides the decision making process into two phases. The first phase lies in the estimation of the decision outcomes using a net of concepts. In the second phase, the proposed model uses a value function to score each possible alternative. The design of the model focuses on some psychological and neurophysiological evidence from current research. In order to validate the model, it is compared with other widely used models that implement different theories of decision making under risk and uncertainty. The model comparison is centered on a well defined task, the Iowa Gambling Task, used in several psychological experiments. The comparison applies an evaluation method based on the optimization of each model in order to emulate human performance individually starting both the participant and the model from the same environmentally available information. The results show that the performance of the proposed model is quantitatively better than the other compared models. Besides, using relevant concepts extracted from interviews with the participants increases the performance of the proposed model.

Genetic testing of candidate genes in arrhythmogenic right ventricular cardiomyopathy/dysplasia

Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is a rare cardiac genetic disease characterized by the presence of structural alterations in the right ventricle which may cause ventricular arrhythmias and may induce sudden cardiac death. ARVC/D has been associated with mutations in genes encoding myocyte adhesion proteins. However, only 30%-50% of patients have mutations in these genes. Genetic testing is useful in obtaining a diagnosis, particularly in individuals who do not completely fulfill clinical criteria, thereby also enabling the undertaking of preventive strategies in family members. The main goal of this study was to identify mutations in candidate genes associated with intercalate disks that could be potentially involved in ARVC/D pathogenesis. We analyze a cohort of 14 Spanish unrelated patients clinically diagnosed with ARVC/D without any genetic alteration in all previously known responsible genes. Thus, a genetic screening has been performed in 7 additional potential candidate genes (ACTC1 -actin alpha cardiac muscle 1-, CDHN -cadherin 2 type 1 or N-cadherin-, CTNNA1 -catenin alpha 1-, Cx43 or GJA1 -gap junction protein alpha 1-, MVCL -Metavinculin-, MYL2 -myosin light chain 2- and MYL3 -myosin light chain 3-) by direct sequencing analysis. Our genetic analysis did not identify any disease-causing mutation. Thirty single nucleotides polymorphisms were found, six of them novel. In conclusion, our ARVC/D Spanish cohort has not shown any mutations in the analyzed candidate genes despite their involvement in formation and maintenance of the intercalated disk.

Contact angioedema and rhinoconjunctivitis caused by Dendrobaena species and Sarcophaga carnaria used as fishing bait

The flesh fly Sarcophaga carnaria is commonly used as fishing bait. Immunoglobulin (Ig) E-mediated reactions caused by the handling of this bait have been reported. The earthworm Dendrobaena species is increasingly being used as fishing bait but there have been no reported cases of allergy to this species to date. We studied a 26-year-old amateur angler who presented rhinoconjunctivitis, urticaria, and angioedema on handling S carnaria. He started to use Dendrobaena species instead but developed the same symptoms. The aim of this study was to identify the allergens involved in the patient's clinical reactions. The study was performed using immunoglobulin (Ig) E immunoblotting and immunoblotting inhibition assays.The patient's serum detected allergens from Dendrobaena species (of an apparent molecular weight of approximately 150, 60, 37, 24, 21 and 19 kDa) and S. carnaria (approximately 70 kDa and a smear ranging from 50 to 40 kDa). The patient was diagnosed with allergy to both Dendrobaena species and 5 carnaria. This is the first case describing Dendrobaena species as an allergic agent.

Morphological traits in Portuguese Bordaleira de Entre Douro e Minho sheep: divergence of the breed

Production of the autochthonous Portuguese sheep breed Bordaleira de Entre Douro e Minho (BEDM) is directly associated with the concept of sustainable agriculture. This concept focuses on the adaptation of animal populations to adverse environmental conditions, high biological efficiency and traditional management. Native BEDM sheep can be divided into the following two types on the basis of their geographic location in Portugal and how they are managed: the Várzea, which is found mainly in the lower Entre Douro e Minho region, and the Mountain type, which traditionally prefers common areas. In the present work, we analysed records of liveweight, 15 body measurements and eight indexes of the BEDM sheep, to explore the ability to distinguish different characteristics between BEDM sheep populations. The records that were obtained and analysed by principal component analysis for 412 BEDM sheep (68 males and 344 females) included the following: heights at withers (HW), at back (HB), at rump (HR) and at chest (HC); lengths of trunk (LT), of rump (LR), of head (LH) and of perineum (LP); widths of head (WH), of chest (WC), of biiliac (WBIIL) and of biischiatic (WBIIS); perimeters of the shin (PS), thorax (PT), and abdomen (PA); and finally indexes such as cephalic index (CI), thoracic index (TI), pelvic index (PI), body index (BI), relative chest depth index (RDCI), lateral corporal index (LCI), relative shin thickness index (RTSI) and dactyl–thoracic index (DTI). The Várzea BEDM was morphologically superior to the Mountain variety, with this superiority more evident in females. Height measurements, especially HW in adult females, provided an excellent measurement reference for biometrical breed studies. Functional index values confirmed the BEDM Mountain variety’s appropriateness for mountainous regions. Relationships among body measurements suggested that the breed standard needed to be updated. The research presented here was used by the Portuguese Ministery to split BEDM into two new breeds; the traditional variety called Várzea now represents the new BEDM breed, whereas the Mountain variety represents the new Churra do Minho breed.

Adsorption of MCPA on goethite and humic acid-coated goethite

Anionic pesticides are adsorbed on the mineral oxide fraction of the soil surface but considerably less on the organic fraction, so that the presence of organic matter causes a decrease in the amount of pesticide adsorbed, and may affect the mechanism of adsorption. In the present study we investigated the adsorption of the weak acid pesticide MCPA on the surface of goethite and of humic acid-coated goethite, selected as models of the mineral oxide fraction and organic components present in soil systems. Adsorption of the anionic form of the pesticide on goethite fitted an S-type isotherm and the amount adsorbed increased as the ionic strength decreased and the pH of the medium decreased. Application of the charge distribution multi site complexation model (CD-MUSIC model) enabled interpretation of the results, which suggested the formation of inner and outer sphere complexes between the pesticide and the singly-coordinated surface sites of goethite. Less pesticide was adsorbed on the humic acid-coated goethite than on the bare goethite and the pattern fitted an L-type isotherm, which indicates a change in the mechanism of adsorption. Simplified calculations with the CD-MUSIC model enabled interpretation of the results, which suggested that the pesticide molecules form the same type of surface complexes as in the previous case.

Role of genetic testing in arrhythmogenic right ventricular cardiomyopathy/dysplasia

In a cohort of patients with confirmed or suspected arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D), genetic testing is useful in confirming the diagnosis, particularly in individuals who do not completely fulfil Task Force criteria for the disease, thereby also enabling the adoption of preventive measures in family members. Due to the high percentage of novel mutations that are expected to be identified in ARVC/D, the use of genetic screening technology based on the identification of known mutations seems to have very restricted value. Our results support that the presence of certain genetic variations could play a role in the final phenotype of patients with ARVC/D, where single and compound mutation carriers would have more symptomatic forms of the disease and the polymorphism P366L could be associated to a more benign phenotype.

Effect of pH and ionic strength on the binding of paraquat and MCPA by soil fulvic and humic acids

The effect of pH and ionic strength on the interaction between pesticides (paraquat and MCPA) and humic substances (soil extracted humic acid and fulvic acid) was interpreted with a simple electrostatic model. Potentiometric titrations were carried out, the charge curves for the humic substances were obtained for three values of ionic strength, and the parameters that define proton binding to humic and fulvic acid were calculated by application of the NICA-Donnan model. The binding isotherms were obtained for paraquat-humic acid and paraquat-fulvic acid at three different pH values and two ionic strengths, and the MCPA-fulvic acid binding isotherms for two pH values and two ionic strengths. Binding experiments were carried out by use of a membrane dialysis technique and the concentrations of pesticide were measured by HPLC. The amount of paraquat bound to the humic substances increased with pH, decreased with increasing ionic strength, decreased in the presence of Ca(2+) and was greater for humic acid than for fulvic acid. Much less binding was observed with MCPA than with paraquat, and therefore the isotherms were not well defined. The application of a simple electrostatic model enabled us to conclude that the effect of pH and ionic strength on binding of paraquat to humic substances is due to the effect that these parameters have on the humic substance charge, and the model provided an excellent reproduction of the experimental binding isotherms.