564 research outputs found

    Plasma Soluble Human Elastin Fragments as an Intra-Aneurysmal Localized Biomarker for Ruptured Intracranial Aneurysm

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    Background—Fragmentation of the tunica media is a hallmark of intracranial aneurysm formation, often leading to aneurysmal progression and subsequent rupture. The objective of this study is to determine the plasma level of elastin fragments in the lumen of ruptured versus unruptured human intracranial aneurysms. Methods and Results—One hundred consecutive patients with/without ruptured saccular intracranial aneurysms undergoing endovascular coiling or stent-assisted coiling were recruited. Blood samples were collected from the lumen of intracranial aneurysm using a microcatheter. The tip of the microcatheter was placed inside the aneurysm’s sac in close proximity to the inner wall of the dome. Plasma levels of elastin fragments were measured using an ELISA-based method. Mean plasma level of soluble human elastin fragments was significantly greater in ruptured aneurysms when compared with nonruptured aneurysms (102.0±15.5 versus 39.3±9.6 ng/mL; P\u3c0.001). Mean plasma level of soluble human elastin fragments did not have significant correlation with age, sex, size, or aneurysm location. Conclusions—The present study revealed that a significantly higher concentration of soluble human elastin fragments in the lumen of ruptured intracranial aneurysms when compared with nonruptured ones. © 2018 The Authors

    Genetic Overview of the Maya Populations: Mitochondrial DNA Haplogroups

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    We identified the mitochondrial DNA haplogroups A, B, C and D in 75 present-day Maya individuals, 24 Maya individuals of the colonial period and one pre-Columbian Maya individual from Quintana Roo, Mexico. We examined these data together with those of 21 Maya populations accounting for 647 present-day Maya individuals and 104 ancient Maya individuals. A demographic study based on the analysis of fertility and endogamy was carried out in two modern Maya populations to identify cultural factors that influence the mitochondrial haplogroup genetic diversity. Most present-day and ancient Maya populations show a distribution pattern of mitochondrial haplogroup frequencies A, C, B and D in decreasing order, with haplogroup D absent in several populations. Considering only modern Maya populations with at least 50 individuals analyzed, the present-day Tzotzil and Lacandon populations from Chiapas show the higher and lower genetic diversities, 0.706 and 0.025 respectively. Our results show small genetic differences between the Maya populations with exception of the present-day Tojolabal and Lacandon populations from Chiapas. The present-day Lacandon population from Chiapas is different to other Maya populations in showing almost only haplogroup A. This result suggests a long history of isolation and endogamy as well as a possible founder effect inside the Lacandonian rain-forest. The contemporary Tojolabal population is the only one with an unusual mitochondrial haplogroup pattern exhibiting a frequency of haplogroup B higher than A and the absence of haplogroup C. With a small sample size, the pre-Columbian Copan Maya show a high content of haplogroup C and a low frequency of haplogroup D. The genetic homogeneity of the Maya populations is indicative of a common origin and nearly continuous gene flow in the long-term within a general isolation of the whole group, conversely to the Nahua populations that had different origins. Our demographic study showed high fertility rates and high levels of endogamy in the present-day Maya populations from Quintana Roo here analyzed that are consistent with their general low genetic diversity. We propose that the genetic similarity among ancient and present-day Maya populations persists due to a strong sense of social cohesion and identity that impacts their marriage practices maintaining this cultural group isolated. These factors have constrained gene flow inside the Maya region and impeded the differentiation among the Maya. Discernment of genetic differentiation within the peninsula is constrained by the lack of sampling documentation in the literature

    Functional ecology of soil microbial communities along a glacier forefield in Tierra del Fuego (Chile)

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    A previously established chronosequence from Pia Glacier forefield in Tierra del Fuego (Chile) containing soils of different ages (from bare soils to forest ones) is analyzed. We used this chronosequence as framework to postulate that microbial successional development would be accompanied by changes in functionality. To test this, the GeoChip functional microarray was used to identify diversity of genes involved in microbial carbon and nitrogen metabolism, as well as other genes related to microbial stress response and biotic interactions. Changes in putative functionality generally reflected succession-related taxonomic composition of soil microbiota. Major shifts in carbon fixation and catabolism were observed, as well as major changes in nitrogen metabolism. At initial microbial dominated succession stages, microorganisms could be mainly involved in pathways that help to increase nutrient availability, while more complex microbial transformations such as denitrification and methanogenesis, and later degradation of complex organic substrates, could be more prevalent at vegetated successional states. Shifts in virus populations broadly reflected changes in microbial diversity. Conversely, stress response pathways appeared relatively well conserved for communities along the entire chronosequence. We conclude that nutrient utilization is likely the major driver of microbial succession in these soils. [Int Microbiol 19(3):161-173 (2016)]Keywords: Functional genes · antibiotic resistance · GeoChip microarray · primary succession · chronosequenc

    Proper motions of field L and T dwarfs -II

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    By using images taken with WFCAM on UKIRT and SofI on the NTT and combining them with 2MASS we have measured proper motions for 126 L and T dwarfs in the dwarf archive. Two of these L dwarfs appear to have M dwarf common proper motion companions, and 2 also appear to be high velocity dwarfs, indicating possible membership of the thick disc. We have also compared the motion of these 126 objects to that of numerous moving groups, and have identified new members of the Hyades, Ursa Major and Pleiades moving groups. These new objects, as well as those identified in Jameson et al. (2008) have allowed us to refine the L dwarf sequence for Ursa Major that was defined by Jameson et al. (2008).Comment: Accepted for publication in MNRAS. 10 pages, 3 figure

    Bird pollination of Canary Island endemic plants

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    The Canary Islands are home to a guild of endemic, threatened bird pollinated plants. Previous work has suggested that these plants evolved floral traits as adaptations to pollination by flower specialist sunbirds, but subsequently they appear to be have co-opted passerine birds as sub-optimal pollinators. To test this idea we carried out a quantitative study of the pollination biology of three of the bird pollinated plants, Canarina canariensis (Campanulaceae), Isoplexis canariensis (Veronicaceae) and Lotus berthelotii (Fabaceae), on the island of Tenerife. Using colour vision models, we predicted the detectability of flowers to bird and bee pollinators. We measured pollinator visitation rates, nectar standing crops, as well as seed set and pollen removal and deposition. These data showed that the plants are effectively pollinated by non-flower specialist passerine birds that only occasionally visit flowers. The large nectar standing crops and extended flower longevities (>10days) of Canarina and Isoplexis suggests that they have evolved bird pollination system that effectively exploits these low frequency non-specialist pollen vectors and is in no way suboptimal. Seed set in two of the three species was high, and was significantly reduced or zero in flowers where pollinator access was restricted. In L. berthelotii, however, no fruit set was observed, probably because the plants were self incompatible horticultural clones of a single genet. We also show that, while all three species are easily detectable for birds, the orange Canarina and the red Lotus (but less so the yellow-orange Isoplexis) should be difficult to detect for insect pollinators without specialised red receptors, such as bumblebees. Contrary to expectations if we accept that the flowers are primarily adapted to sunbird pollination, the chiffchaff (Phylloscopus canariensis) was an effective pollinator of these species

    Alta proporción de macrodisco en pacientes de dos centros oftalmológicos en el occidente de Honduras

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    Background: When the optic nerve has a surface greater than 2.5mm2, and without associated pathologies, it is a macrodisc, whose excavation is proportional to its increased size. Based on the distribution under the Gauss curve, it can be defined as a “macrodisc” when it is more than 2 standard deviations above the mean. Only 2.3% of the population is expected to exceed these limits. Objective: To determine the average optic disc size and the proportion of macrodisc in the population without glaucoma or retinal pathologies that attends two ophthalmological clinics in Western Honduras in the period from July 2021 to July 2022. Methods: Retrospective descriptive study. Morphometric parame-ters of the optic disc were measured using ZEISS Cirrus HD Model 4000 Optical Coherence Tomography. Macrodisc was defined as: optic disc area >2.5 mm2 and disc area of the mean plus twofold standard deviations. Results: The proportion of macrodisc was 31% considering the definition of disc area >2.5 mm2, and 3% con-sidering the definition based on the distribution under the Gauss curve (>3.17mm2). An average optic disc area of 2.28±0.45 mm2was obtained, cup/disc (C/D) ratio of 0.59±0.13, vertical C/D ratio of 0.56±0.13, neuroretinal rim area of 1.37±0.22 mm2, retinal nerve fiber layer thickness (CFNR) of 97.4±10.664μm. Discussion:The average disc area obtained is greater than Caucasians, like Hispanics, and less than Afro-descendants and Asians

    Scrophularia arguta, a widespread annual plant in the Canary Islands: a single recent colonization event or a more complex phylogeographic pattern?

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    Many studies have addressed evolution and phylogeography of plant taxa in oceanic islands, but have primarily focused on endemics because of the assumption that in widespread taxa the absence of morphological differentiation between island and mainland populations is due to recent colonization. In this paper, we studied the phylogeography of Scrophularia arguta, a widespread annual species, in an attempt to determine the number and spatiotemporal origins of dispersal events to Canary Islands. Four different regions, ITS and ETS from nDNA and psbA-trnH and psbJ-petA from cpDNA, were used to date divergence events within S. arguta lineages and determine the phylogenetic relationships among populations. A haplotype network was obtained to elucidate the phylogenetic relationships among haplotypes. Our results support an ancient origin of S. arguta (Miocene) with expansion and genetic differentiation in the Pliocene coinciding with the aridification of northern Africa and the formation of the Mediterranean climate. Indeed, results indicate for Canary Islands three different events of colonization, including two ancient events that probably happened in the Pliocene and have originated the genetically most divergent populations into this species and, interestingly, a recent third event of colonization of Gran Canaria from mainland instead from the closest islands (Tenerife or Fuerteventura). In spite of the great genetic divergence among populations, it has not implied any morphological variation. Our work highlights the importance of nonendemic species to the genetic richness and conservation of island flora and the significance of the island populations of widespread taxa in the global biodiversity.Trabajo financiado por: Ministerio de Ciencia e Innovación y Fondos FEDER. Proyecto CGL2011-24140 (I+D+i)peerReviewe
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