GDF15 promotes simultaneous astrocyte remodeling and tight junction strengthening at the blood–brain barrier

Perivascular astrocyte processes (PAP) surround cerebral endothelial cells (ECs) and modulate the strengthening of tight junctions to influence blood–brain barrier (BBB) permeability. Morphologically altered astrocytes may affect barrier properties and trigger the onset of brain pathologies. However, astrocyte-dependent mediators of these events remain poorly studied. Here, we show a pharmacologically driven elevated expression and release of growth/differentiation factor 15 (GDF15) in rat primary astrocytes and cerebral PAP. GDF15 has been shown to possess trophic properties for motor neurons, prompting us to hypothesize similar effects on astrocytes. Indeed, its increased expression and release occurred simultaneously to morphological changes of astrocytes in vitro and PAP, suggesting modulatory effects of GDF15 on these cells, but also neighboring EC. Administration of recombinant GDF15 was sufficient to promote astrocyte remodeling and enhance barrier properties between ECs in vitro, whereas its pharmacogenetic abrogation prevented these effects. We validated our findings in male high anxiety-related behavior rats, an animal model of depressive-like behavior, with shrunk PAP associated with reduced expression of the junctional protein claudin-5, which were both restored by a pharmacologically induced increase in GDF15 expression. Thus, we identified GDF15 as an astrocyte-derived trigger of astrocyte process remodeling linked to enhanced tight junction strengthening at the BBB.     

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Psychotherapie Forum -     

Multi‐tissue cytogenetic analysis for the diagnosis of mosaic Down syndrome: A case report

Less than one percent of individuals with Down syndrome exhibit mosaicism, a biological phenomenon that describes an individual who has two or more genetically distinct cell lines. The percentage of mosaicism in different tissues can impact the presence of clinical findings and hinder cytogenetic diagnosis. We report a case of mosaicism for trisomy 21 diagnosed after multi‐tissue cytogenetic analysis of peripheral blood and buccal mucosa, associated with significant intellectual disability, dysmorphic facial features, congenital heart defects, macropenis, and imperforate anus.     

Revealing the Pb Whisker Growth Mechanism from Al-Alloy Surface and Morphological Dependency on Material Stress and Growth Environment

Spontaneous metallic Pb whisker formation from Pb and Bi containing Al-alloy’s surfaces is a newly discovered phenomenon. The whiskers display unique formations, growth and morphology, which give the opportunity to be applied for specialized sensor and electronics applications. Within this work, the impact of environmental conditions (gas composition and moisture) is investigated and correlated with the modification of whisker evolution and growth dynamics. Furthermore, the residual stress state of the aluminum matrix using deep cryogenic treatment is modified and used to further increase whisker nucleation and growth by up to three- and seven-fold, respectively, supported by quantitative results. The results of this paper indicate the possibility to manipulate the whisker not only in terms of their kinetics but also their morphology (optimal conditions are 20% O₂ and 35% humidity). Such features allow the tailoring of the whisker structure and surface to volume ratio, which can be optimized for different applications. Finally, this research provides new insight into the growth dynamics of the whiskers through in situ and ex situ measurements, providing further evidence of the complex nucleation and growth mechanisms that dictate the spontaneous growth of Pb whiskers from Al-alloy 6026 surfaces with growth velocities up to 1.15 µm/s.     

Mineralogical and Technological Characterization of Zeolites from Basin and Range as Pozzolanic Addition of Cement

The present paper assesses petrographic, mineralogical, chemical, and technological features of different zeolitic tuff samples from various western USA districts of the Basin and Range Province containing mainly erionite, mordenite, clinoptilolite/heulandite and phillipsite. The aim of this characterization is to evaluate the pozzolanic activity of these samples according to European normative UNI-EN 196/5 (Fratini test) to program a possible use as addition for blended cements. Petrographic and mineralogical results show that the two phillipsite-bearing tuffs have a higher theoretical Cation Exchange Capacity (CEC) than the other samples; technological characterization shows a pozzolanic behavior for all the samples but higher for the tuff samples containing phillipsite, which shows a higher reactivity with CaO. All the samples could be thus advantageously employed for the preparation of blended cements, potentially reducing CO₂ emissions by 70–90%.