1,720,983 research outputs found
Analysis and distribution of per- and polyfluoroalkyl substances in decidua and villi placenta explants
Full text linkPlacenta mediates the transfer of nutrients, oxygen and drugs from mother to fetus. It is constituted by two cellular layers separated by the intervillous space: the outer is in direct contact with maternal blood (decidua placenta), and the inner (villi) directly in contact with the fetus. Environmental contaminants, such as per-and polyfluoroalkyl substances (PFAS) also demonstrated the ability to cross the tissue multiple layers, posing at risk the health of the fetus. The aim of the present study was to analyse the PFAS amount in decidua and villi placenta explants and to study differences in their distribution among the two side of this organ. The determination of 23 PFAS was carried out by liquid chromatography coupled to high-resolution accurate mass spectrometry (LC-HRAM). Our research included women who delivered at term between 2021 and 2022. Our data indicated that all samples contained at least one PFAS, demonstrating the ubiquitarian presence of these compounds in our population. A high occurrence of PFOS, PFOA and PFHxS, followed by PFHxA, PFBS and PFUnA was found. The fluorotelomer 6:2 FTS was also present in more than 40% of samples and this represent the first data on placenta explants. Mean and median PFAS values for decidual explants were 0.5 ng/g and 0.4 ng/g (SD 0.3), while for villi explants mean and median values were 0.6 ng/g and 0.4 ng/g (SD 0.4). A different pattern of accumulation was observed between villi and decidual explants for PFOS, PFOA and PFUnA (villi > decidua) and PFHxA, PFHxS, PFBS and 6:2 FTS (decidua > villi). Even if the mechanism of this selectively accumuation is not yet understood, molecular degree of ionization and its lipophilicity could at least in part explain this difference. This study ex-pands the limited data describing PFAS levels in the placenta and pose attention on PFAS exposure during pregnancy
HIF-1α expression by immunohistochemistry and mRNA-210 levels by real time polymerase chain reaction in post-mortem cardiac tissues: A pilot study
Full text linkIntroduction: The postmortem diagnosis of acute myocardial ischemia (AMI) represents a challenging issue in forensic practice. Immunohistochemical studies and gene expression studies are becoming a promising field of research in forensic pathology. The present study aims to evaluate HIF-1α expression through immunohistochemistry (IHC), and mRNA-210 level using real-time polymerase chain reaction (RT-PCR), in order to define if HIF-1α and mRNA-210 in post-mortem myocardium could be adopted in the diagnosis of AMI. Materials and Methods: Thirty-five deceased individuals, who underwent forensic autopsy at the Legal Medicine Service of the University of Parma, between 2010 and 2018, were investigated. The cohort was divided into two groups according to the cause of death (sudden deaths caused by AMI vs control cases). Cardiac specimens were collected during autopsy, then samples were processed for morphological evaluation using haematoxylin–eosin staining, for IHC, and for RT-PCR. HIF-1α expression and mRNA-210 levels were investigated. Results: Statistical evaluation demonstrated statistically significant differences in terms of number of IHC positive vessels, leukocytes, and cardiomyocytes between the two groups. Moreover, in the majority of cases, immunostaining positivity was observed only in myocardial and subendocardial samples. With reference to mRNA-210, the difference between the two groups proved to be statistically significant. Conclusions: The present study indicates that HIF-1α and mRNA-210 in post-mortem cardiac specimens could represent appropriate biomarkers in the diagnosis of AMI. The current study was primarily limited by the scarcity of the cohort, so further research is required to confirm these preliminary observations
Mineral fibres and asbestos bodies in human lung tissue: A case study
Full text linkOne of the open questions regarding the asbestos problem is the fate of the mineral fibres in the body once inhaled and deposited in the deep respiratory system. In this context, the present paper reports the results of an electron microscopy study of both mineral fibres and asbestos bodies found in the lung tissue of a patient who died of malignant mesothelioma due to past occupational exposure. In concert with previous in vivo animal studies, our data provide evidence that amphibole asbestos fibres are durable in the lungs, whereas chrysotile fibres are transformed into a silica-rich product, which can be easily cleared. Amphibole fibres recovered from samples of tissue of the deceased display a high degree of crystallinity but also show a very thin amorphous layer on their surface; 31% of the fibres are coated with asbestos bodies consisting of a mixture of ferroproteins (mainly ferritin). Here, we propose an improved model for the coating process. Formation of a coating on the fibres is a defence mechanism against fibres that are longer than 10 μm and thinner than 0.5 μm, which macrophages cannot engulf. The mature asbestos bodies show signs of degradation, and the iron stored in ferritin may be released and potentially increase oxidative stress in the lung tissue
Cellularity Defects Are Not Ubiquitous in the Brains of Fetuses With Down Syndrome
No full textDown syndrome (DS) is a genetic pathology characterized by various developmental defects. Unlike other clinical problems, intellectual disability is an invariant clinical trait of DS. Impairment of neurogenesis accompanied by brain hypotrophy is a typical neurodevelopmental phenotype of DS, suggesting that a reduction in the number of cells forming the brain may be a key determinant of intellectual disability. Previous evidence showed that fetuses with DS exhibit widespread hypocellularity in brain regions belonging to the temporal lobe memory systems, which may account for the typical explicit memory impairment that characterizes DS. In the current study, we have examined the basal ganglia, the insular cortex (INS), and the cingulate cortex (CCX) of fetuses with DS and age-matched controls (18–22 weeks of gestation), to establish whether cellularity defects involve regions that are not primarily involved in explicit memory. We found that fetuses with DS exhibit a notable hypocellularity in the putamen (−30%) and globus pallidus (−35%). In contrast, no cellularity differences were found in the INS and CCX, indicating that hypocellularity is not ubiquitous in the DS brain. The hypocellularity found in the basal ganglia, which are critically implicated in the control of movement, suggests that such alterations may contribute to the motor abnormalities of DS. The normal cytoarchitecture of the INS and CCX suggests that the alterations exhibited by people with DS in functions in which these regions are involved are not attributable to neuron paucity
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
CYP2B6, ABCB1 and OPRM1 profile in a stillborn affected by chronic methadone intoxication
No full textVariations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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