scholarly journals Probing tissue-scale deformation by in vivo force application reveals a fast tissue softening during early embryogenesis

2017 ◽  
Author(s):  
Arturo D’Angelo ◽  
Kai Dierkes ◽  
Carlo Carolis ◽  
Guillaume Salbreux ◽  
Jérôme Solon
Keyword(s):  
Material Properties ◽  
Rapid Change ◽  
Early Embryogenesis ◽  
Tissue Response ◽  
Mechanical Parameters ◽  
Major Contributor ◽  
Pharmacological Treatments ◽  
Tissue Material ◽  
Over Time

AbstractDuring development, cell-generated forces induce tissue-scale deformations to shape the organism. Here, we present a method that allows to quantitatively relate such tissue-scale deformations to spatially localized forces and measure mechanical properties of epithelia in vivo. Our approach is based on the application of controlled forces on microparticles embedded in individual cells of an embryo. Combining measurements of the bead displacement with the analysis of induced deformation fields in a continuum mechanics framework, we can quantify tissue material properties and follow their change over time. In particular, we uncover a rapid change in tissue response occurring during Drosophila cellularization, resulting from a softening of the blastoderm and an increase of external friction. Pharmacological treatments reveal that in addition to actomyosin, the microtubule cytoskeleton is a major contributor to epithelial mechanics at that stage. Overall, our method allows for measuring essential mechanical parameters governing tissue-scale deformations and flows occurring during morphogenesis.

scholarly journals Lineage commitment of embryonic cells involves MEK1-dependent clearance of pluripotency regulator Ventx2

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Pierluigi Scerbo ◽  
Leslie Marchal ◽  
Laurent Kodjabachian
Keyword(s):  
Cell Division ◽  
Cell Fate ◽  
Early Embryogenesis ◽  
Embryonic Cells ◽  
Pluripotent Cells ◽  
Embryonic Tissues ◽  
Pluripotency Gene ◽  
Related Transcription Factor ◽  
Over Time

During early embryogenesis, cells must exit pluripotency and commit to multiple lineages in all germ-layers. How this transition is operated in vivo is poorly understood. Here, we report that MEK1 and the Nanog-related transcription factor Ventx2 coordinate this transition. MEK1 was required to make Xenopus pluripotent cells competent to respond to all cell fate inducers tested. Importantly, MEK1 activity was necessary to clear the pluripotency protein Ventx2 at the onset of gastrulation. Thus, concomitant MEK1 and Ventx2 knockdown restored the competence of embryonic cells to differentiate. Strikingly, MEK1 appeared to control the asymmetric inheritance of Ventx2 protein following cell division. Consistently, when Ventx2 lacked a functional PEST-destruction motif, it was stabilized, displayed symmetric distribution during cell division and could efficiently maintain pluripotency gene expression over time. We suggest that asymmetric clearance of pluripotency regulators may represent an important mechanism to ensure the progressive assembly of primitive embryonic tissues.

scholarly journals Microindentation for in vivo measurement of bone tissue material properties in atypical femoral fracture patients and controls

2012 ◽  
Vol 28 (1) ◽  
pp. 162-168 ◽  
Author(s):  
Roberto C Güerri-Fernández ◽  
Xavier Nogués ◽  
José M Quesada Gómez ◽  
Elisa Torres del Pliego ◽  
Lluís Puig ◽  
...  
Keyword(s):  
Bone Tissue ◽  
Material Properties ◽  
Femoral Fracture ◽  
Atypical Femoral Fracture ◽  
In Vivo Measurement ◽  
Tissue Material

The Development of Homologous (Canine/Anti-Canine) Antibodies in Dogs with Haemophilia A (Factor VIII Deficiency): A Ten-Year Longitudinal Study

1993 ◽  
Vol 69 (01) ◽  
pp. 021-024 ◽  
Author(s):  
Shawn Tinlin ◽  
Sandra Webster ◽  
Alan R Giles
Keyword(s):  
Factor Viii ◽  
Canine Model ◽  
Significant Inhibition ◽  
Human Condition ◽  
Haemophilia A ◽  
Variable Expression ◽  
The Family ◽  
Over Time

SummaryThe development of inhibitors to factor VIII in patients with haemophilia A remains as a serious complication of replacement therapy. An apparently analogous condition has been described in a canine model of haemophilia A (Giles et al., Blood 1984; 63:451). These animals and their relatives have now been followed for 10 years. The observation that the propensity for inhibitor development was not related to the ancestral factor VIII gene has been confirmed by the demonstration of vertical transmission through three generations of the segment of the family related to a normal (non-carrier) female that was introduced for breeding purposes. Haemophilic animals unrelated to this animal have not developed functionally significant factor VIII inhibitors despite intensive factor VIII replacement. Two animals have shown occasional laboratory evidence of factor VIII inhibition but this has not been translated into clinical significant inhibition in vivo as assessed by clinical response and F.VIII recovery and survival characteristics. Substantial heterogeneity of inhibitor expression both in vitro and in vivo has been observed between animals and in individual animals over time. Spontaneous loss of inhibitors has been observed without any therapies designed to induce tolerance, etc., being instituted. There is also phenotypic evidence of polyclonality of the immune response with variable expression over time in a given animal. These observations may have relevance to the human condition both in determining the pathogenetic factors involved in this condition and in highlighting the heterogeneity of its expression which suggests the need for caution in the interpretation of the outcome of interventions designed to modulate inhibitor activity.

Cytocompatibility and Material Properties of Poly-carbonate Urethane/Carbon Nanofiber Composites for Neural Applications

2003 ◽  
Vol 774 ◽  
Author(s):  
Janice L. McKenzie ◽  
Michael C. Waid ◽  
Riyi Shi ◽  
Thomas J. Webster
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanofibers ◽  
Material Properties ◽  
Carbon Nanofiber ◽  
Scar Tissue ◽  
Tissue Response ◽  
Positive Interactions ◽  
Weight Percentage ◽  
Poly Carbonate

AbstractCarbon nanofibers possess excellent conductivity properties, which may be beneficial in the design of more effective neural prostheses, however, limited evidence on their cytocompatibility properties exists. The objective of the present in vitro study was to determine cytocompatibility and material properties of formulations containing carbon nanofibers to predict the gliotic scar tissue response. Poly-carbonate urethane was combined with carbon nanofibers in varying weight percentages to provide a supportive matrix with beneficial bulk electrical and mechanical properties. The substrates were tested for mechanical properties and conductivity. Astrocytes (glial scar tissue-forming cells) were seeded onto the substrates for adhesion. Results provided the first evidence that astrocytes preferentially adhered to the composite material that contained the lowest weight percentage of carbon nanofibers. Positive interactions with neurons, and, at the same time, limited astrocyte functions leading to decreased gliotic scar tissue formation are essential for increased neuronal implant efficacy.

scholarly journals Prevalence and Photobiology of Photosynthetic Dinoflagellate Endosymbionts in the Nudibranch Berghia stephanieae

Animals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 2200
Author(s):  
Ruben X. G. Silva ◽  
Paulo Cartaxana ◽  
Ricardo Calado
Keyword(s):  
Food Deprivation ◽  
Photosynthetic Efficiency ◽  
Rapid Decrease ◽  
Complete Loss ◽  
Symbiotic Association ◽  
Non Invasive ◽  
Sea Slugs ◽  
Non Destructive ◽  
Over Time

Berghia stephanieae is a stenophagous sea slug that preys upon glass anemones, such as Exaiptasia diaphana. Glass anemones host photosynthetic dinoflagellate endosymbionts that sea slugs ingest when consuming E. diaphana. However, the prevalence of these photosynthetic dinoflagellate endosymbionts in sea slugs appears to be short-lived, particularly if B.stephanieae is deprived of prey that host these microalgae (e.g., during bleaching events impacting glass anemones). In the present study, we investigated this scenario, along with food deprivation, and validated the use of a non-invasive and non-destructive approach employing chlorophyll fluorescence as a proxy to monitor the persistence of the association between sea slugs and endosymbiotic photosynthetic dinoflagellates acquired through the consumption of glass anemones. Berghia stephanieae deprived of a trophic source hosting photosynthetic dinoflagellate endosymbionts (e.g., through food deprivation or by feeding on bleached E. diaphana) showed a rapid decrease in minimum fluorescence (Fo) and photosynthetic efficiency (Fv/Fm) when compared to sea slugs fed with symbiotic anemones. A complete loss of endosymbionts was observed within 8 days, confirming that no true symbiotic association was established. The present work opens a new window of opportunity to rapidly monitor in vivo and over time the prevalence of associations between sea slugs and photosynthetic dinoflagellate endosymbionts, particularly during bleaching events that prevent sea slugs from incorporating new microalgae through trophic interactions.

scholarly journals Burst of Corneal Dendritic Cells during Trastuzumab and Paclitaxel Treatment

Diagnostics ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 838
Author(s):  
Katharina A. Sterenczak ◽  
Nadine Stache ◽  
Sebastian Bohn ◽  
Stephan Allgeier ◽  
Bernd Köhler ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Dendritic Cells ◽  
Cancer Therapy ◽  
Adverse Effects ◽  
Laser Scanning Microscopy ◽  
Sensory Nerves ◽  
Confocal Laser ◽  
Corneal Nerves ◽  
Over Time

During breast cancer therapy, paclitaxel and trastuzumab are both associated with adverse effects such as chemotherapy-induced peripheral neuropathy and other systemic side effects including ocular complications. Corneal nerves are considered part of the peripheral nervous system and can be imaged non-invasively by confocal laser scanning microscopy (CLSM) on the cellular level. Thus, in vivo CLSM imaging of structures of the corneal subbasal nerve plexus (SNP) such as sensory nerves or dendritic cells (DCs) can be a powerful tool for the assessment of corneal complications during cancer treatment. During the present study, the SNP of a breast cancer patient was analyzed over time by using large-scale in vivo CLSM in the course of paclitaxel and trastuzumab therapy. The same corneal regions could be re-identified over time. While the subbasal nerve morphology did not alter significantly, a change in dendritic cell density and an additional local burst within the first 11 weeks of therapy was detected, indicating treatment-mediated corneal inflammatory processes. Ocular structures such as nerves and dendritic cells could represent useful biomarkers for the assessment of ocular adverse effects during cancer therapy and their management, leading to a better visual prognosis.

In vivo praziquantel efficacy of Schistosoma japonicum over time: a systematic review and meta-analysis

Acta Tropica ◽  
2021 ◽  
pp. 106048
Author(s):  
Qiu-Fu Yu ◽  
Jie-Ying Zhang ◽  
Meng-Tao Sun ◽  
Man-Man Gu ◽  
Hui-Ying Zou ◽  
...  
Keyword(s):  
Systematic Review ◽  
Schistosoma Japonicum ◽  
Meta Analysis ◽  
Over Time

scholarly journals Ultramicronized Palmitoylethanolamide (um-PEA): A New Possible Adjuvant Treatment in COVID-19 patients

2021 ◽  
Vol 14 (4) ◽  
pp. 336
Author(s):  
Annalisa Noce ◽  
Maria Albanese ◽  
Giulia Marrone ◽  
Manuela Di Lauro ◽  
Anna Pietroboni Zaitseva ◽  
...  
Keyword(s):  
Adjuvant Treatment ◽  
Pulmonary Involvement ◽  
In Vivo Studies ◽  
Pharmacological Treatments ◽  
Beneficial Effects ◽  
Coronavirus Infection ◽  
Ultramicronized Palmitoylethanolamide ◽  
Potential Use

The Coronavirus Disease-19 (COVID-19) pandemic has caused more than 100,000,000 cases of coronavirus infection in the world in just a year, of which there were 2 million deaths. Its clinical picture is characterized by pulmonary involvement that culminates, in the most severe cases, in acute respiratory distress syndrome (ARDS). However, COVID-19 affects other organs and systems, including cardiovascular, urinary, gastrointestinal, and nervous systems. Currently, unique-drug therapy is not supported by international guidelines. In this context, it is important to resort to adjuvant therapies in combination with traditional pharmacological treatments. Among natural bioactive compounds, palmitoylethanolamide (PEA) seems to have potentially beneficial effects. In fact, the Food and Drug Administration (FDA) authorized an ongoing clinical trial with ultramicronized (um)-PEA as an add-on therapy in the treatment of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) infection. In support of this hypothesis, in vitro and in vivo studies have highlighted the immunomodulatory, anti-inflammatory, neuroprotective and pain-relieving effects of PEA, especially in its um form. The purpose of this review is to highlight the potential use of um-PEA as an adjuvant treatment in SARS-CoV-2 infection.

In vivo behavior of trimethylene carbonate and ε-caprolactone-based (co)polymer networks: Degradation and tissue response

2010 ◽  
Vol 95A (3) ◽  
pp. 940-949 ◽  
Author(s):  
Erhan Bat ◽  
Josée A. Plantinga ◽  
Martin C. Harmsen ◽  
Marja J. A. van Luyn ◽  
Jan Feijen ◽  
...  
Keyword(s):  
Polymer Networks ◽  
Tissue Response ◽  
Trimethylene Carbonate

The Role of Mechanical Tension in Neurons

2010 ◽  
Vol 1274 ◽  
Author(s):  
Taher Saif ◽  
Jagannathan Rajagopalan ◽  
Alireza Tofangchi
Keyword(s):  
Mechanical Response ◽  
Mechanical Forces ◽  
Active Tension ◽  
Mechanical Tension ◽  
Deformation Response ◽  
Linear Force ◽  
Tension Regulation ◽  
Over Time

AbstractWe used high resolution micromechanical force sensors to study the in vivo mechanical response of embryonic Drosophila neurons. Our experiments show that Drosophila axons have a rest tension of a few nN and respond to mechanical forces in a manner characteristic of viscoelastic solids. In response to fast externally applied stretch they show a linear force-deformation response and when the applied stretch is held constant the force in the axons relaxes to a steady state value over time. More importantly, when the tension in the axons is suddenly reduced by releasing the external force the neurons actively restore the tension, sometimes close to their resting value. Along with the recent findings of Siechen et al (Proc. Natl. Acad. Sci. USA 106, 12611 (2009)) showing a link between mechanical tension and synaptic plasticity, our observation of active tension regulation in neurons suggest an important role for mechanical forces in the functioning of neurons in vivo.

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