Evolutionary Changes in the Complexity of the Tectum of Nontetrapods: A Cladistic Approach

Background: The tectum is a structure localized in the roof of the midbrain in vertebrates, and is taken to be highly conserved in evolution. The present article assessed three hypotheses concerning the evolution of lamination and citoarchitecture of the tectum of nontetrapod animals: 1) There is a significant degree of phylogenetic inertia in both traits studied (number of cellular layers and number of cell classes in tectum); 2) Both traits are positively correlated accross evolution after correction for phylogeny; and 3) Different developmental pathways should generate different patterns of lamination and cytoarchitecture. Methodology/Principal Findings: The hypotheses were tested using analytical-computational tools for phylogenetic hypothesis testing. Both traits presented a considerably large phylogenetic signal and were positively associated. However, no difference was found between two clades classified as per the general developmental pathways of their brains. Conclusions/Significance: The evidence amassed points to more variation in the tectum than would be expected by phylogeny in three species from the taxa analysed; this variation is not better explained by differences in the main course of development, as would be predicted by the developmental clade hypothesis. Those findings shed new light on th

Brain-heart crosstalk: the many faces of stress-related cardiomyopathy syndromes in anaesthesia and intensive care.

Neurogenic stress cardiomyopathy (NSC) is a well-known syndrome complicating the early phase after an acute brain injury, potentially affecting outcomes. This article is a review of recent data on the putative role of localization and lateralization of brain lesions in NSC, cardiac innervation abnormalities, and new polymorphisms and other genetic causes of the sympathetic nervous system over-activity. Concerns regarding the management of stress-related cardiomyopathy syndromes during the perioperative period are also discussed. Future clinical research should explore whether specific factors explain different patient susceptibilities to the disease and should be directed towards early identification and stratification of patients at risk, so that such patients can be more carefully monitored and appropriately managed in critical care and during the perioperative perio

Cell Fate of Retinal Progenitor Cells: In Ovo UbC-StarTrack Analysis

Clonal cell analysis outlines the ontogenic potential of single progenitor cells, allowing the elucidation of the neural heterogeneity among different cell types and their lineages. In this work, we analyze the potency of retinal stem/progenitor cells through development using the chick embryo as a model. We implemented in ovo the clonal genetic tracing strategy UbC-StarTrack for tracking retinal cell lineages derived from individual progenitors of the ciliary margin at E3.5 (HH21-22). The clonal assignment of the derived-cell progeny was performed in the neural retina at E11.5-12 (HH38) through the identification of sibling cells as cells expressing the same combination of fluorophores. Moreover, cell types were assessed based on their cellular morphology and laminar location. Ciliary margin derived-cell progenies are organized in columnar associations distributed along the peripheral retina with a limited tangential dispersion. The analysis revealed that, at the early stages of development, this region harbors multipotent and committed progenitor cells

Influence of non-occupational sources on the levels of biomarkers of internal dose for use in biological monitoring of occupational exposure to extremely low concentrations of benzene

To study how traditional (t,t-muconic acid--t,t-MA and S-phenylmercapturic--SPMA) and new (urinary benzene) urinary biomarkers of internal dose can contribute to exclude an occupational source of exposure to extremely low concentrations of benzene, also analyzing the influence that non-occupational sources of exposure, such as cigarette smoking and urban pollution, can have on the levels of these biomarkers.Assessment was made of 6 workers employed at a groundwater purification plant polluted by benzene (exposed) and 6 administrative clerks employed at the same plant (controls); both groups included smokers and non-smokers. Environmental monitoring (fixed and personal samplings lasting 8 hours) and biological monitoring (determinations of t,t-MA, SPMA, urinary benzene, and urinary creatinine so as to apply suitable adjustments) were performed in exposed workers on 10 successive days, including also rest days (background exposure), and in controls only once.Airborne benzene always resulted lower than the limit of detection of the analytical method in both fixed and personal samplings done on exposed workers and controls during working days, while personal samplings done on exposed workers during rest days showed benzene concentrations even higher than 5 microg/m3, that is the limit value for ambient air quality. Concentrations of t,t-MA, SPMA and urinary benzene did not show differences between exposed workers, regardless of whether they were studied on working or rest days, and controls and appeared to be largely within the reference value range for the Italian population. All biomarkers of internal dose examined in the study showed significantly higher values in smokers than non-smokers. In the latter, SPMA was always below the limit of detection, while urinary benzene resulted higher than the limit of detection in 60.0\% and 87.5\% of the determinations done on working and on rest days, respectively.In situations of occupational exposure to extremely low doses of benzene or of absence of exposure, the application of an integrated environmental--biological monitoring approach, involving the determination of SPMA and/or urinary benzene, together with a careful evaluation of those factors determining non-occupational exposure to the toxicant, seems indispensable in order to be able to exclude the presence of occupational exposure. In these particular situations of occupational exposure to benzene, the interpretation of the results of environmental and biological monitoring should not only consider the TLV or BEI, but also the limit value for ambient air quality and the reference value for the general population, since benzene is able to determine genotoxic carcinogenic effects even at exposure to extremely low concentrations of the toxicant

Ruolo dei fattori non occupazionali nel condizionare i livelli di indicatori di dose interna utilizzati per monitorare l\u2019esposizione occupazionale a concentrazioni molto molto basse di benzene

RIASSUNTO. INTRODUZIONE. Studiare il contributo che tradizionali (acido t,t-muconico - t,t-MA ed S-fenilmercapturico - SPMA) e nuovi (benzene urinario) biomarcatori urinari di dose interna possono fornire per escludere l\u2019origine occupazionale di esposizioni a concentrazioni molto molto basse di benzene, considerando altres\uec l\u2019influenza che fonti di esposizione non occupazionale ad esso, quali fumo di sigaretta ed inquinamento delle aree urbane, possono avere sui livelli di questi indicatori. MATERIALI E METODI. Sono stati esaminati 6 lavoratori che operavano presso un impianto di depurazione di acqua di falda contaminata da benzene (esposti) e 6 impiegati amministrativi che lavoravano presso la stessa azienda (controlli); entrambi i gruppi comprendevano fumatori e non fumatori. Il monitoraggio ambientale (campionamenti fissi e personali della durata di 8 ore) ed il monitoraggio biologico (determinazione di t,t-MA, SPMA, benzene urinario, creatinina urinaria per la correzione dei biomarcatori) sono stati effettuati negli esposti per 10 giorni consecutivi, comprendenti anche i giorni di riposo (ambienti di vita), e nei controlli una sola volta. RISULTATI. L\u2019esposizione ambientale a benzene \ue8 risultata sempre inferiore al limite di rilevabilit\ue0 della metodica analitica in tutti i campionamenti, sia fissi che personali, eseguiti su esposti e controlli durante i giorni di lavoro, mentre le misurazioni personali effettuate sugli esposti durante i giorni di riposo hanno mostrato concentrazioni di benzene anche superiori a 5 μg/m3, che rappresenta il valore limite di qualit\ue0 dell\u2019aria degli ambienti di vita. Le concentrazioni di t,t-MA, SPMA e benzene urinario non hanno mostrato differenze tra esposti, indipendentemente se considerati nei giorni di lavoro o di riposo, e controlli e sono apparse sostanzialmente comprese nel range dei valori di riferimento per la popolazione italiana. Per tutti gli indicatori di dose interna studiati sono stati osservati valori significativamente pi\uf9 alti nei fumatori rispetto ai non fumatori. In questi ultimi, l\u2019SPMA \ue8 risultato sempre inferiore al limite di rilevabilit\ue0 mentre il benzene urinario \ue8 risultato dosabile nel 60.0% delle determinazioni effettuate nei giorni di lavoro e nell\u201987.5% di quelle effettuate nei giorni di riposo. CONCLUSIONI. In condizioni di esposizione occupazionale molto molto bassa o assente a benzene, per escludere l\u2019esposizione occupazionale si rende indispensabile applicare un approccio integrato monitoraggio ambientale - monitoraggio biologico con determinazione di SPMA e/o benzene urinario, insieme ad un\u2019attenta valutazione dei fattori che possono aver determinato un\u2019esposizione non occupazionale al tossico. In queste particolari situazioni di esposizione occupazionale a benzene l\u2019interpretazione dei risultati del monitoraggio ambientale e di quello biologico non deve tenere conto soltanto dei TLV o degli IBE, ma anche dei valori limite di qualit\ue0 dell\u2019aria degli ambienti di vita e rispettivamente dei valori di riferimento della popolazione generale, considerata la possibilit\ue0 di comparsa degli effetti cancerogeni genotossici del benzene anche a concentrazioni di esposizione molto molto basse