Low impact of different SNP panels from two building-loci pipelines on RAD-Seq population genomic metrics: case study on five diverse aquatic species.

BACKGROUND: The irruption of Next-generation sequencing (NGS) and restriction site-associated DNA sequencing (RAD-seq) in the last decade has led to the identification of thousands of molecular markers and their genotyping for refined genomic screening. This approach has been especially useful for non-model organisms with limited genomic resources. Many building-loci pipelines have been developed to obtain robust single nucleotide polymorphism (SNPs) genotyping datasets using a de novo RAD-seq approach, i.e. without reference genomes. Here, the performances of two building-loci pipelines, STACKS 2 and Meyer's 2b-RAD v2.1 pipeline, were compared using a diverse set of aquatic species representing different genomic and/or population structure scenarios. Two bivalve species (Manila clam and common edible cockle) and three fish species (brown trout, silver catfish and small-spotted catshark) were studied. Four SNP panels were evaluated in each species to test both different building-loci pipelines and criteria for SNP selection. Furthermore, for Manila clam and brown trout, a reference genome approach was used as control. RESULTS: Despite different outcomes were observed between pipelines and species with the diverse SNP calling and filtering steps tested, no remarkable differences were found on genetic diversity and differentiation within species with the SNP panels obtained with a de novo approach. The main differences were found in brown trout between the de novo and reference genome approaches. Genotyped vs missing data mismatches were the main genotyping difference detected between the two building-loci pipelines or between the de novo and reference genome comparisons. CONCLUSIONS: Tested building-loci pipelines for selection of SNP panels seem to have low influence on population genetics inference across the diverse case-study scenarios here studied. However, preliminary trials with different bioinformatic pipelines are suggested to evaluate their influence on population parameters according with the specific goals of each study.

A global community effort to decipher the unique biology of annual killifish.

Over the past 50 years, annual killifishes arose as alternative model organisms for studies of vertebrate biology. The annual fish offers exceptional advantages for studies of genetics, genomics, developmental biology, population dynamics, ecology, biogeography, and evolution. They inhabit extremely variable freshwater environments in Africa and South America, have a short lifespan and a set of unique and fascinating developmental characteristics. Embryos survive within the dry substrate during the dry season, whereas the adult population dies. Thus, the survival of the populations is entirely dependent on the buried embryos that hatch the next rainy season. Although Old and New World species share similarities in their life cycle, they also have different adaptive responses associated with climate-related selective pressures. Therefore, contrasting different species from these areas is essential to understand unique adaptations to heterogeneous environment. A network of laboratories (United States, Czech Republic, Italy, Brazil, Chile, and Uruguay) is working and collaborating on many aspects of the biology of annual fishes. Participating researchers share projects and cross-training undergraduate and graduate students. These efforts resulted in two International Symposia (2010 and 2015) that took place in Montevideo and an international book. Herein, we summarize the progress made by this global community of scientists. Developmental Dynamics 246:807-811, 2017. © 2017 Wiley Periodicals, Inc.

First complete mitochondrial genome of the South American annual fish Austrolebias charrua (Cyprinodontiformes: Rivulidae): peculiar features among cyprinodontiforms mitogenomes.

BACKGROUND: Among teleosts, the South American genus Austrolebias (Cyprinodontiformes: Rivulidae) includes 42 taxa of annual fishes divided into five different species groups. It is a monophyletic genus, but morphological and molecular data do not resolve the relationship among intrageneric clades and high rates of substitution have been previously described in some mitochondrial genes. In this work, the complete mitogenome of a species of the genus was determined for the first time. We determined its structure, gene order and evolutionary peculiar features, which will allow us to evaluate the performance of mitochondrial genes in the phylogenetic resolution at different taxonomic levels. RESULTS: Regarding gene content and order, the circular mitogenome of A. charrua (17,271 pb) presents the typical pattern of vertebrate mitogenomes. It contains the full complement of 13 proteins-coding genes, 22 tRNA, 2 rRNA and one non-coding control region. Notably, the tRNA-Cys was only 57 bp in length and lacks the D-loop arm. In three full sibling individuals, heteroplasmatic condition was detected due to a total of 12 variable sites in seven protein-coding genes. Among cyprinodontiforms, the mitogenome of A. charrua exhibits the lowest G+C content (37 %) and GCskew, as well as the highest strand asymmetry with a net difference of T over A at 1st and 3rd codon positions. Considering the 12 coding-genes of the H strand, correspondence analyses of nucleotide composition and codon usage show that A and T at 1st and 3rd codon positions have the highest weight in the first axis, and segregate annual species from the other cyprinodontiforms analyzed. Given the annual life-style, their mitogenomes could be under different selective pressures. All 13 protein-coding genes are under strong purifying selection and we did not find any significant evidence of nucleotide sites showing episodic selection (dN >dS) at annual lineages. When fast evolving third codon positions were removed from alignments, the "supergene" tree recovers our reference species phylogeny as well as the Cytb, ND4L and ND6 genes. Therefore, third codon positions seem to be saturated in the aforementioned coding regions at intergeneric Cyprinodontiformes comparisons. CONCLUSIONS: The complete mitogenome obtained in present work, offers relevant data for further comparative studies on molecular phylogeny and systematics of this taxonomic controversial endemic genus of annual fishes.

Coevolution between Contracaecum (Nematoda, Anisakidae) and Austrolebias (Cyprinodontiformes, Rivulidae) host-parasite complex from SW Atlantic coastal basins.

In recent years, molecular studies in host-parasite interactions in terms of coevolution have become important. Larvae (L3) of two species of Contracaecum were found parasitizing species of Rivulidae in the Atlantic coastal basins from Uruguay. The aim of this study is to determine the patterns of differentiation of this host-parasite complex in order to clarify possible coevolutionary events in such interaction throughout phylogeographic approach using both nuclear and mitochondrial molecular markers (internal transcribed spacers (ITS) and cytochrome oxidase subunit 1 (cox-1)). Based on both markers, intraspecific variation in Contracaecum species was lower than 2 %, while interspecific variation was greater than 10 %. Both species of Contracaecum constitute monophyletic groups. Contracaecum resulted in a paraphyletic genus when incorporating other Contracaecum species and closely related nematode sequences from GenBank. ITS regions showed that Contracaecum sp. 1 is more closely related to other species of the same genus than with their counterparts from Atlantic coastal basins in Uruguay. Haplotype network for both markers corroborate the existence of two distinct taxa. While ITS pairwise FST comparisons and the indirect estimate of gene flow confirm the existence of two distinct Contracaecum species, mitochondrial gene detected low levels of migrants between some of the populations from both species. Our results suggest that coevolution in this host-parasite complex species is plausible. Parasite cladogenetic events occur almost simultaneously with the separation of the hypothetical ancestors of each species complex of Austrolebias during Pliocene. Additionally, the two lineages of Contracaecum colonize differently the species within each of the Austrolebias complexes.

Sex determination in annual fishes: Searching for the master sex-determining gene in Austrolebias charrua (Cyprinodontiformes, Rivulidae).

Evolution of sex determination and differentiation in fishes involves a broad range of sex strategies (hermaphroditism, gonochorism, unisexuality, environmental and genetic sex determination). Annual fishes inhabit temporary ponds that dry out during the dry season when adults die. The embryos exhibit an atypical developmental pattern and remain buried in the bottom mud until the next rainy season. To elucidate genomic factors involved in the sex determination in annual fish, we explored the presence of a candidate sex-specific gene related to the cascade network in Austrolebias charrua. All phylogenetic analyses showed a high posterior probability of occurrence for a clade integrated by nuclear sequences (aprox. 900 bp) from both adults (male and female), with partial cDNA fragments of A. charrua from juveniles (male) and the dsx D. melanogaster gene. The expressed fragment was detected from blastula to adulthood stages showing a sexually dimorphic expression pattern. The isolated cDNA sequence is clearly related to dsx D. melanogaster gene and might be located near the top of the sex determination cascade in this species.

First report of Spirometra (Eucestoda; Diphyllobothriidae) naturally occurring in a fish host.

Spirometra Faust, Campbell et Kellogg, 1929 is a genus of cestodes belonging to the family Diphyllobothriidae. To date, amphibians, reptiles, and mammals are known second intermediate hosts of these parasites; humans can also be infected (the zoonotic disease is known as sparganosis or spirometrosis). Although the number of phylogenetic studies on Spirometra spp. has increased worldwide in recent years, there are few in South America. Specifically in Uruguay, molecular studies have shown that tapeworms of S. decipiens (Diesing, 1850) complexes 1 and 2 are present in this country. In this study, we characterised the larvae of Spirometra present in the annual fish Austrolebias charrua Costa et Cheffe. Phylogenetic analysis of the cytochrome c oxidase subunit I (COI) sequences of these larvae showed that they belong to S. decipiens complex 1. This is the first report of teleost fishes serving as a second intermediate host for tapeworms of the genus Spirometra in nature.

Aging, Physical Exercise, Telomeres, and Sarcopenia: A Narrative Review.

Human aging is a gradual and adaptive process characterized by a decrease in the homeostatic response, leading to biochemical and molecular changes that are driven by hallmarks of aging, such as oxidative stress (OxS), chronic inflammation, and telomere shortening. One of the diseases associated with the hallmarks of aging, which has a great impact on functionality and quality of life, is sarcopenia. However, the relationship between telomere length, sarcopenia, and age-related mortality has not been extensively studied. Moderate physical exercise has been shown to have a positive effect on sarcopenia, decreasing OxS and inflammation, and inducing protective effects on telomeric DNA. This results in decreased DNA strand breaks, reduced OxS and IA, and activation of repair pathways. Higher levels of physical activity are associated with an apparent increase in telomere length. This review aims to present the current state of the art of knowledge on the effect of physical exercise on telomeric maintenance and activation of repair mechanisms in sarcopenia.

The Supplementation of Sechium edule var. nigrum spinosum (Chayote) Promotes Nrf2-Mediated Antioxidant Protection in Older Adults with Metabolic Syndrome.

The aim was to determine the effect of Sechium edule var. nigrum spinosum (chayote) on gene expression related to antioxidant protection mechanisms and the inflammatory process in older adults with metabolic syndrome (MetS). A quasi-experimental study was carried out in a convenience sample of 46 older adults diagnosed with MetS: (i) placebo group (PG; n = 20); (ii) experimental group (EG; n = 26). The clinical, biochemical, anthropometric parameters and SOD, GPx, and CAT enzyme activity, alongside total oxidant status (TOS), total antioxidant status (TAS), oxidative stress index (OSI), cytokines (IL-6, IL-8 and TNF-α), and mRNA expression of SOD, GPx, CAT, IL-6, IL-8, TNF-α, Nrf2, NFkB p50, and NFkB p65, were measured at baseline and 6 months post-intervention. A statistically significant decrease was observed in TOS (baseline, 28.9 ± 3.6 vs. post, 23.7 ± 3.4, p < 0.01) and OSI (baseline, 24.1 ± 3.8 vs. post, 17.7 ± 4), as well as an increase in IL-6 (baseline, 10.7 ± 1.1 vs. post, 12.3 ± 2, p = 0.03), SOD activity (baseline, 167.1 ± 11.9 vs. post, 180.6 ± 7.6, p < 0.05), CAT activity (baseline, 1.0 ± 0.2 vs. post, 1.3 ± 0.2, p < 0.01), and TAS (baseline, 1.1 ± 0.1 vs. post, 1.4 ± 0.1, p < 0.01) in the EG compared to the PG. Regarding the expression of Nrf2, SOD, and IL-6, the EG showed a significant increase vs. basal levels (47%, 44%, and 43%, respectively). Our findings suggest that Sechium edule supplementation promotes the antioxidant response and decreases oxidative stress via Nrf2.

The consumption of Sechium edule (chayote) has antioxidant effect and prevents telomere attrition in older adults with metabolic syndrome.

OBJECTIVE: To determine the effect of the consumption of Sechium edule (1.5 g/day) for six months on oxidative stress (OxS) and inflammation markers and its association with telomere length (TL) in older adults with metabolic syndrome (MetS). METHODS: The study was conducted in a sample of 48 older adults: placebo (EP) and experimental (EG) groups. Lipoperoxides, protein carbonylation, 8-OHdG, total oxidant status (TOS), SOD, GPx, H2O2 inhibition, total antioxidant status (TAS), inflammatory cytokines (IL6, IL10, TNF-α), and TL were measured before and six months post-treatment. RESULTS: We found a significant decrease in the levels of lipoperoxides, protein carbonylation, 8-OHdG, TOS in the EG in comparison PG. Likewise, a significante increase of TAS, IL-6, and IL-10 levels was found at six months post-treatment in EG in comparison with PG. TL showed a statistically significant decrease in PG compared to post-treatment EG. CONCLUSIONS: Our findigns showed that the supplementation of Sechium edule has antioxidant, and anti-inflammatory effects, and diminushion of shortening of telomeric DNA in older adults with MetS. This would be the first study that shows that the intervention with Sechium edule has a possible geroprotective effect by preventing telomeres from shortening as usually happens in these patients. Therefore, suggesting a protection of telomeric DNA and genomic DNA.

Comorbidity and nutritional status in adult with advanced chronic kidney disease influence the decision-making choice of renal replacement therapy modality: A retrospective 5-year study.

Background: Nutritional and inflammation status are significant predictors of morbidity and mortality risk in advanced chronic kidney disease (ACKD). To date, there are a limited number of clinical studies on the influence of nutritional status in ACKD stages 4-5 on the choice of renal replacement therapy (RRT) modality. Aim: This study aimed to examine relationships between comorbidity and nutritional and inflammatory status and the decision-making on the choice of RRT modalities in adults with ACKD. Methods: A retrospective cross-sectional study was conducted on 211 patients with ACKD with stages 4-5 from 2016 to 2021. Comorbidity was assessed using the Charlson comorbidity index (CCI) according to severity (CCI: ≤ 3 and >3 points). Clinical and nutritional assessment was carried out by prognosis nutritional index (PNI), laboratory parameters [serum s-albumin, s-prealbumin, and C-reactive protein (s-CRP)], and anthropometric measurements. The initial decision-making of the different RRT modalities [(in-center, home-based hemodialysis (HD), and peritoneal dialysis (PD)] as well as the informed therapeutic options (conservative treatment of CKD or pre-dialysis living donor transplantation) were recorded. The sample was classified according to gender, time on follow-up in the ACKD unit (≤ 6 and >6 months), and the initial decision-making of RRT (in-center and home-RRT). Univariate and multivariate regression analyses were carried out for evaluating the independent predictors of home-based RRT. Results: Of the 211 patients with ACKD, 47.4% (n = 100) were in stage 5 CKD, mainly elderly men (65.4%). DM was the main etiology of CKD (22.7%) together with hypertension (96.6%) as a CV risk factor. Higher CCI scores were significantly found in men, and severe comorbidity with a CCI score > 3 points was 99.1%. The mean time of follow-up time in the ACKD unit was 9.6 ± 12.8 months. A significantly higher CCI was found in those patients with a follow-up time > 6 months, as well as higher mean values of eGFR, s-albumin, s-prealbumin, s-transferrin, and hemoglobin, and lower s-CRP than those with a follow-up <6 months (all, at least p < 0.05). The mean PNI score was 38.9 ± 5.5 points, and a PNI score ≤ 39 points was found in 36.5%. S-albumin level > 3.8 g/dl was found in 71.1% (n = 150), and values of s-CRP ≤ 1 mg/dl were 82.9% (n = 175). PEW prevalence was 15.2%. The initial choice of RRT modality was higher in in-center HD (n = 119 patients; 56.4%) than in home-based RRT (n = 81; 40.5%). Patients who chose home-based RRT had significantly lower CCI scores and higher mean values of s-albumin, s-prealbumin, s-transferrin, hemoglobin, and eGFR and lower s-CRP than those who chose in-center RRT (p < 0.001). Logistic regression demonstrated that s-albumin (OR: 0.147) and a follow-up time in the ACKD unit >6 months (OR: 0.440) were significantly associated with the likelihood of decision-making to choose a home-based RRT modality (all, at least p < 0.05). Conclusion: Regular monitoring and follow-up of sociodemographic factors, comorbidity, and nutritional and inflammatory status in a multidisciplinary ACKD unit significantly influenced decision-making on the choice of RRT modality and outcome in patients with non-dialysis ACKD.

Living in Temporary Ponds Loading Giant Genomes: The Neotropical Annual Killifish Genus Austrolebias as New Outstanding Evolutionary Model.

The term Annual killifish describes a short-lived and amazing group of vertebrates inhabiting temporary ponds exposed to an extremely variable environment during its short lifespan in South America and Africa, leading to the death of the entire adult population during the dry season. Austrolebias is a specious genus of the family Rivulidae, with ∼58 currently recognized species, extensively distributed in the temperate Neotropical region. Herein, we reviewed different aspects of the evolutionary biology with emphasis on the genome dynamic linked to the burst speciation process in this genus. Austrolebias constitutes an excellent model to study the genomic evolutionary processes underlying speciation events, since all the species of this genus analyzed so far share an unusually large genome size, with an average DNA content of 5.95 ± 0.45 picograms per diploid cell (mean C-value of about 2.98 pg). The drastic nuclear DNA-increasing would be associated with a considerable proportion of transposable elements (TEs) found in the Austrolebias genomes. The genomic proportion of the moderately repetitive DNA in the A. charrua genome represents approximately twice (45%) the amount of the repetitive components of the highly related sympatric and syntopic rivulinae taxon Cynopoecilus melanotaenia (25%), as well as from other rivulids and actinopterygian fish. These events could explain the great genome instability, the high genetic diversity, chromosome variability, as well as the morphological diversity in species of Austrolebias. Thus, species of this genus represent new model systems linking different evolutionary processes: drastic genome increase, massive TEs genomic representation, high chromosome instability, occurrence of natural hybridization between sister species, and burst speciation events.

An Evaluation of Serological Tests to Determine Postvaccinal Immunity to SARS-CoV-2 by mRNA Vaccines.

BACKGROUND: The duration of the protective efficacy of vaccines against SARS-CoV-2 is unknown. Thus, an evaluation of the clinical performance of available tests is required. OBJECTIVES: To evaluate the clinical performance of LFIA immunoassay compared to ELIA and CLIA immunoassays available in Europe for the detection of IgG antibodies generated by mRNA vaccines against SARS-CoV-2. METHODS: Two automated immunoassays (the EUROIMMUN anti-SARS-CoV-2 IgG S1 ELISA and the LIAISON de Diasorin anti-SARS-CoV-2 IgG S1/S2 test) and a lateral flow immunoassay (the Livzon LFIA anti-SARS-CoV-2 IgG S test) were tested. We analyzed 300 samples distributed in three groups: 100 subjects aged over 18 years and under 45 years, 100 subjects aged between 45 and 65 years, and 100 subjects aged over 65 years. The samples were collected before vaccination; at 21 days; and then at 1, 2, 3, and 6 months after vaccination. The sensitivity, specificity, positive predictive value, negative predictive value, positive probability quotient, negative probability quotient, and concordance (kappa index) were calculated for each serological test. RESULTS: The maximum sensitivity values for IgG were 98.7%, 98.1%, and 97.8% for the EUROIMMUN ELISA, Abbott CLIA, and Livzon LFIA tests, respectively, and the maximum specificity values for IgG were 99.4%, 99.9%%, and 98.4% for the ELISA, CLIA, and LFIA tests, respectively, at the third month after vaccination, representing a decrease in the antibody levels after the sixth month. The best agreement was observed between the ELISA and CLIA tests at 100% (k = 1.00). The agreement between the ELIA, CLIA, and LFIA tests was 99% (k = 0.964) at the second and third month after vaccination. Seroconversion was faster and more durable in the younger age groups. CONCLUSION: Our study examined the equivalent and homogeneous clinical performance for IgG of three immunoassays after vaccination and found LFIA to be the most cost-effective, reliable, and accurate for routine use in population seroconversion and seroprevalence studies.

Nutritional Predictors of Mortality after 10 Years of Follow-Up in Patients with Chronic Kidney Disease at a Multidisciplinary Unit of Advanced Chronic Kidney Disease.

Nutritional monitoring in advanced chronic kidney disease (ACKD) units provides personalized care and improves clinical outcomes. This study aimed to identify mortality risk factors in chronic kidney disease (CKD) patients on nutritional follow-up in the multidisciplinary ACKD unit. A retrospective cross-sectional observational study was conducted in 307 CKD patients' stage 3b, 4−5 followed-up for 10 years. Clinical and nutritional monitoring was performed by malnutrition-inflammation score (MIS), biochemical parameters (s-albumin, s-prealbumin, and serum C-reactive protein (s-CRP), body composition measured by bioelectrical impedance analysis (BIA), anthropometry, and handgrip strength measurements. The sample was classified into non-survivors, survivors, and censored groups. Of the 307 CKD patients, the prevalence of protein-energy wasting (PEW) was 27.0% using MIS > 5 points, s-CRP > 1 mg/dL was 19.20%, and 27.18% died. Survivors had higher significant body cell mass (BCM%) and phase angle (PA). Survival analyses significantly showed that age > 72 years, MIS > 5 points, s-prealbumin ≤ 30 mg/dL, PA ≤ 4°, and gender-adjusted handgrip strength (HGS) were associated with an increased risk of mortality. By univariate and multivariate Cox regression, time on follow-up (HR:0.97), s-prealbumin (HR:0.94), and right handgrip strength (HR:0.96) were independent predictors of mortality risk at 10 years of follow-up in the ACKD unit. Nutritional monitoring in patients with stage 3b, 4−5 CKD helps to identify and treat nutritional risk early and improve adverse mortality prognosis.

Antioxidant and Anti-Inflammatory Effect of the Consumption of Powdered Concentrate of Sechium edule var. nigrum spinosum in Mexican Older Adults with Metabolic Syndrome.

Metabolic syndrome (MetS) has a high prevalence in older adults and is a risk factor for cardiovascular diseases and complications of old age. It has also been related to oxidative stress (OxS) and chronic inflammation (CI) and their consequent alterations. Therefore, it is important to propose therapeutic alternatives such as the consumption of Sechium edule (Chayote), since hypoglycemic, hypotensive, and lipogenesis inhibitor properties are attributed to it. We carried out a study in 81 older adults (OA) with MetS to determine the effect of consumption of chayote powder concentrate (500 mg, three times a day) for six months, with a baseline measurement, at three and six months in an experimental group (EG) (n = 41) and a placebo group (PG) (n = 40), all with a diagnosis of MetS according to the criteria of National Adult Treatment Panel of the National Cholesterol Program III (NCEP/ATP III). Anthropometric, biochemical, OxS markers, and inflammation measurements were performed on all participants, basal, three, and six months after. A statistically significant decrease was found in the concentration of lipoperoxides (TBARS), 8-isoprostanes, 8-OHdG, oxidative stress score (OSS), HbA1c, blood pressure, and in the number of MetS diagnostic criteria, as well as an increase in total antioxidant status (TAS), antioxidant gap (GAP), superoxide dismutase (SOD), interleukin 10 (IL-10), and HDL-cholesterol in EG. The results suggest that the consumption of Sechium edule powder has a hypotensive, hypoglycemic, antioxidant, and anti-inflammatory effect in OA with MetS and reduced the percentage of patients with MetS.

Micrometric measurement of the density of stained odontoblast processes.

UNLABELLED: The embryological, structural and functional unit of the dentine-pulp complex shares the odontoblast, located in the border of the dentine pulp, with basal nuclei and organelles. The odontoblast process emerges from its apical pole. It is formed by microtubules, microfilaments and vesicles covered by membranes penetrating the dentinal tubules, isolated from the inter-tubular matrix, along the extent of the dentine. The objective of this study was to evaluate the efficacy of three staining techniques: hematoxylin-eosin, periodic acid-Schiff and Schmorl, by staining the process, from beginning to end, and compare the results with the erosion technique. Thirty human teeth were employed in the trial; after their extraction the pulp was fixated, the pieces demineralized in nitric acid at 8%, the collagen filaments eliminated with Type II Collagenase, the tissue was stained, and the measurements were made. The portions with no pulp were prepared with the erosion technique. RESULTS: Comparing the best results obtained by staining with the values obtained with the erosion technique, the former showed lower values. CONCLUSION: Staining techniques show lower density of the staining processes compared with the dentinal tubules in the erosion technique.

Magnetic resonance imaging in patients with self-locating peritoneal catheters: Is it safe?

The fact that self-locating catheters have a piece of metal at the tip leads to doubt and uncertainty around performing magnetic resonance imaging (MRI) in patients with this type of catheter. We simulated a peritoneum with a weighted catheter to ascertain how the catheter behaved during MRI scans in 1.5 T and 3 T machines. We also reviewed cases in which MRI had been performed in patients with this type of catheter. In the simulation, the tip of the self-locating peritoneal catheter caused a magnetic susceptibility artefact that made it difficult to see nearby areas, but it proved to be a safe device for MRI. 14 MRI scans were performed in patients with self-locating catheters, none in the abdominal area. There were no complications in the patients or the technique after performing MRI.

Telomere Length and Oxidative Stress and Its Relation with Metabolic Syndrome Components in the Aging.

A great amount of scientific evidence supports that Oxidative Stress (OxS) can contribute to telomeric attrition and also plays an important role in the development of certain age-related diseases, among them the metabolic syndrome (MetS), which is characterised by clinical and biochemical alterations such as obesity, dyslipidaemia, arterial hypertension, hyperglycaemia, and insulin resistance, all of which are considered as risk factors for type 2 diabetes mellitus (T2DM) and cardiovascular diseases, which are associated in turn with an increase of OxS. In this sense, we review scientific evidence that supports the association between OxS with telomere length (TL) dynamics and the relationship with MetS components in aging. It was analysed whether each MetS component affects the telomere length separately or if they all affect it together. Likewise, this review provides a summary of the structure and function of telomeres and telomerase, the mechanisms of telomeric DNA repair, how telomere length may influence the fate of cells or be linked to inflammation and the development of age-related diseases, and finally, how the lifestyles can affect telomere length.

Magnetic resonance imaging in patients with self-locating peritoneal catheters: Is it safe? / Resonancia magnética en pacientes con catéteres peritoneales autoposicionantes: ¿se puede?

The fact that self-locating catheters have a piece of metal at the tip leads to doubt and uncertainty around performing magnetic resonance imaging (MRI) in patients with this type of catheter. We simulated a peritoneum with a weighted catheter to ascertain how the catheter behaved during MRI scans in 1.5T and 3T machines. We also reviewed cases in which MRI had been performed in patients with this type of catheter. In the simulation, the tip of the self-locating peritoneal catheter caused a magnetic susceptibility artefact that made it difficult to see nearby areas, but it proved to be a safe device for MRI. 14 MRI scans were performed in patients with self-locating catheters, none in the abdominal area. There were no complications in the patients or the technique after performing MRI.

Population Genomics in Rhamdia quelen (Heptapteridae, Siluriformes) Reveals Deep Divergence and Adaptation in the Neotropical Region.

Rhamdia quelen, a Neotropical fish with hybridization between highly divergent mitochondrial DNA (mtDNA) lineages, represents an interesting evolutionary model. Previous studies suggested that there might be demographic differences between coastal lagoons and riverine environments, as well as divergent populations that could be reproductively isolated. Here, we investigated the genetic diversity pattern of this taxon in the Southern Neotropical Basin system that includes the La Plata Basin, Patos-Merin lagoon basin and the coastal lagoons draining to the SW Atlantic Ocean, through a population genomics approach using 2b-RAD-sequencing-derived single nucleotide polymorphisms (SNPs). The genomic scan identified selection footprints associated with divergence and suggested local adaptation environmental drivers. Two major genomic clusters latitudinally distributed in the Northern and Southern basins were identified, along with consistent signatures of divergent selection between them. Population structure based on the whole set of loci and on the presumptive neutral vs. adaptive loci showed deep genomic divergence between the two major clusters. Annotation of the most consistent SNPs under divergent selection revealed some interesting candidate genes for further functional studies. Moreover, signals of adaptation to a coastal lagoon environment mediated by purifying selection were found. These new insights provide a better understanding of the complex evolutionary history of R. quelen in the southernmost basin of the Neotropical region.

Effect of Sechium edule var. nigrum spinosum (Chayote) on Telomerase Levels and Antioxidant Capacity in Older Adults with Metabolic Syndrome.

Patients with metabolic syndrome (MetS) have a redox imbalance, due to a decay in antioxidant capacity. Oxidative stress (OxS) is considered an important modulator of telomere shortening and telomerase activity. One of the fruits that has been associated with an antioxidant effect is Sechium edule and although its properties are well established, there is only one exploratory study evaluating its effectiveness in patients with MetS. The present investigation is a much more robust and controlled study, including a placebo group. Hence, we determined the effect of consumption of the dried fruit powder (500 mg, three times per day) for three months. We measured effects on telomerase levels, antioxidant capacity, and markers for OxS. The study was performed in a sample of 75 older adults: placebo group (n = 30) and experimental group (n = 45) with the diagnosis of MetS according to the National Adult Treatment Panel of the National Cholesterol Program III (NCEP/ATP III) criteria. All markers were measured before and after three months of treatment. There was a statistically significant decrease in lipoperoxides and protein carbonylation with an increased superoxide dismutase (SOD), as well as sustained levels of telomerase in patients who consumed Sechium edule. Our findings suggest that consumption of this fruit has a hypoglycemic, hypotensive, and antioxidant effect, without altering telomerase levels, which could suggest better protection against telomere shortening.