In-Vitro Stress Relaxation Response of Neonatal Peripheral Nerves

Abstract Background Schwann cells (SCs) play a crucial role in the repair of peripheral nerves. This is due to their ability to proliferate, migrate, and provide trophic support to axon regrowth. During peripheral nerve injury, SCs de-differentiate and reprogram to gain the ability to repair nerves. Cysteine-rich 61 (Cyr61/CCN1) is a member of the CCN family of matrix cell proteins and have been reported to be abundant in the secretome of repair mediating SCs. In this study we investigate the function of Cyr61 in SCs. Results We observed Cyr61 was expressed both in vivo and in vitro. The promoting effect of Cyr61 on SC proliferation and migration was through autocrine and paracrine mechanisms. SCs expressed αvβ3 integrin and the effect of Cyr61 on SC proliferation and migration could be blocked via αvβ3 integrin. Cyr61 could influence c-Jun protein expression in cultured SCs. Conclusions In this study, we found that Cyr61 promotes SC proliferation and migration via αvβ3 integrin and regulates c-Jun expression. Our study contributes to the understanding of cellular and molecular mechanisms underlying SC’s function during nerve injury, and thus, may facilitate the regeneration of peripheral nerves after injury.

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Effect of thermal exposure on the strength and stress relaxation response of AA-7075-T6 material

Materials Chemistry and Physics ◽

10.1016/j.matchemphys.2021.124791 ◽

2021 ◽

pp. 124791

Author(s):

M.Z. Butt ◽

Samee Ullah ◽

M. Rashid Khan ◽

Sajjad Ahmad ◽

Syed Zafar Ilyas

Keyword(s):

Stress Relaxation ◽

Thermal Exposure ◽

Relaxation Response ◽

Aa 7075

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Enlisting the Ixodes scapularis Embryonic ISE6 Cell Line to Investigate the Neuronal Basis of Tick—Pathogen Interactions

Pathogens ◽

10.3390/pathogens10010070 ◽

2021 ◽

Vol 10 (1) ◽

pp. 70

Author(s):

Lourdes Mateos-Hernández ◽

Natália Pipová ◽

Eléonore Allain ◽

Céline Henry ◽

Clotilde Rouxel ◽

...

Keyword(s):

Cell Line ◽

Peripheral Nerves ◽

Ixodes Scapularis ◽

Embryonic Cell ◽

Cell Subpopulation ◽

In Vivo Experiments

Neuropeptides are small signaling molecules expressed in the tick central nervous system, i.e., the synganglion. The neuronal-like Ixodes scapularis embryonic cell line, ISE6, is an effective tool frequently used for examining tick–pathogen interactions. We detected 37 neuropeptide transcripts in the I. scapularis ISE6 cell line using in silico methods, and six of these neuropeptide genes were used for experimental validation. Among these six neuropeptide genes, the tachykinin-related peptide (TRP) of ISE6 cells varied in transcript expression depending on the infection strain of the tick-borne pathogen, Anaplasma phagocytophilum. The immunocytochemistry of TRP revealed cytoplasmic expression in a prominent ISE6 cell subpopulation. The presence of TRP was also confirmed in A. phagocytophilum-infected ISE6 cells. The in situ hybridization and immunohistochemistry of TRP of I. scapularis synganglion revealed expression in distinct neuronal cells. In addition, TRP immunoreaction was detected in axons exiting the synganglion via peripheral nerves as well as in hemal nerve-associated lateral segmental organs. The characterization of a complete Ixodes neuropeptidome in ISE6 cells may serve as an effective in vitro tool to study how tick-borne pathogens interact with synganglion components that are vital to tick physiology. Therefore, our current study is a potential stepping stone for in vivo experiments to further examine the neuronal basis of tick–pathogen interactions.

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Developmental potential of neural crest-derived cells migrating from segments of developing quail bowel back-grafted into younger chick host embryos

Development ◽

10.1242/dev.109.2.411 ◽

1990 ◽

Vol 109 (2) ◽

pp. 411-423 ◽

Cited By ~ 11

Author(s):

T.P. Rothman ◽

N.M. Le Douarin ◽

J.C. Fontaine-Perus ◽

M.D. Gershon

Keyword(s):

Neural Crest ◽

Neural Tube ◽

Peripheral Nerves ◽

Sympathetic Ganglia ◽

Limb Bud ◽

Pigment Cells ◽

Developmental Potential ◽

Migratory Experience ◽

Host Embryo

The technique of back-transplantation was used to investigate the developmental potential of neural crest-derived cells that have migrated to and colonized the avian bowel. Segments of quail bowel (removed at E4) were grafted between the somites and neural tube of younger (E2) chick host embryos. Grafts were placed at a truncal level, adjacent to somites 14–24. Initial experiments, done in vitro, confirmed that crest-derived cells are capable of migrating out of segments of foregut explanted at E4. The foregut, which at E4 has been colonized by cells derived from the vagal crest, served as the donor tissue. Comparative observations were made following grafts of control tissues, which included hindgut, lung primordia, mesonephros and limb bud. Additional experiments were done with chimeric bowel in which only the crest-derived cells were of quail origin. Targets in the host embryos colonized by crest-derived cells from the foregut grafts included the neural tube, spinal roots and ganglia, peripheral nerves, sympathetic ganglia and the adrenals, but not the gut. Donor cells in these target organs were immunostained by the monoclonal antibody, NC-1, indicating that they were crest-derived and developing along neural or glial lineages. Some of the crest-derived cells (NC-1-immunoreactive) that left the bowel and reached sympathetic ganglia, but not peripheral nerves or dorsal root ganglia, co-expressed tyrosine hydroxylase immunoreactivity, a neural characteristic never expressed by crest-derived cells in the avian gut. None of the cells leaving enteric back-grafts produced pigment. Cells of mesodermal origin were also found to leave donor explants and aggregate in dermis and feather germs near the grafts. These observations indicate that crest-derived cells, having previously migrated to the bowel, retain the ability to migrate to distant sites in a younger embryo. The routes taken by these cells appear to reflect, not their previous migratory experience, but the level of the host embryo into which the graft is placed. Some of the population of crest-derived cells that leave the back-transplanted gut remain capable of expressing phenotypes that they do not express within the bowel in situ, but which are appropriate for the site in the host embryo to which they migrate.

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In vitro stress effect on degradation and drug release behaviors of basic fibroblast growth factor – poly(lactic-co-glycolic-acid) microsphere

Drug Design Development and Therapy ◽

10.2147/dddt.s93554 ◽

2016 ◽

pp. 431 ◽

Cited By ~ 5

Author(s):

Yan Xiong ◽

Zeping Yu ◽

Yun Lang ◽

Hong Li ◽

Yonggang Yan ◽

...

Keyword(s):

Growth Factor ◽

Drug Release ◽

Fibroblast Growth Factor ◽

Basic Fibroblast Growth Factor ◽

Glycolic Acid ◽

Stress Effect ◽

Fibroblast Growth ◽

In Vitro Stress

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Mechanics of the cellular microenvironment as perceived by cells in vivo

10.1101/2021.01.04.425259 ◽

2021 ◽

Author(s):

Alessandro Mongera ◽

Marie Pochitaloff ◽

Hannah J. Gustafson ◽

Georgina A. Stooke-Vaughan ◽

Payam Rowghanian ◽

...

Keyword(s):

Stress Relaxation ◽

Mechanical Parameters ◽

Cellular Microenvironment ◽

Stem Cell Maintenance ◽

Quantitative Studies ◽

Cell Proliferation And Differentiation ◽

3D Microenvironment ◽

Proliferation And Differentiation

Tissue morphogenesis and repair, as well as organ homeostasis, require cells to constantly monitor their 3D microenvironment and adapt their behaviors in response to local biochemical and mechanical cues1-6. In vitro studies have shown that substrate stiffness and stress relaxation are important mechanical parameters in the control of cell proliferation and differentiation, stem cell maintenance, cell migration 7-11, as well as tumor progression and metastasis12,13. Yet, the mechanical parameters of the microenvironment that cells perceive in vivo, within 3D tissues, remain unknown. In complex materials with strain- and time-dependent material properties, the perceived mechanical parameters depend both on the strain and timescales at which the material is mechanically probed14. Here, we quantify in vivo and in situ the mechanics of the cellular microenvironment that cells probe during vertebrate presomitic mesoderm (PSM) specification. By analyzing the magnitude and dynamics of endogenous, cell-generated strains, we show that individual cells preferentially probe the stiffness associated with deformations of the supracellular, foam-like tissue architecture. We reveal how stress relaxation leads to a perceived microenvironment stiffness that decreases over time, with cells probing the softest regime. While stress relaxation timescales are spatially uniform in the tissue, most mechanical parameters, including those probed by cells, vary along the anteroposterior axis, as mesodermal progenitors commit to different lineages. Understanding the mechanical parameters that cells probe in their native 3D environment is important for quantitative studies of mechanosensation in vivo2-4,6,15 and can help design scaffolds for tissue engineering applications16-18.

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Post-Fatigue Creep and Stress Relaxation Response of a Hybrid Polymer Composite

Volume 14: Emerging Technologies; Materials: Genetics to Structures; Safety Engineering and Risk Analysis ◽

10.1115/imece2017-71177 ◽

2017 ◽

Author(s):

Raghu V. Prakash ◽

Monalisha Maharana

Keyword(s):

Stress Relaxation ◽

Polymer Composites ◽

Polymer Composite ◽

Fatigue Loading ◽

Synthetic Fiber ◽

Relaxation Response ◽

Hybrid Polymer ◽

Fatigue Cycling ◽

Creep And Stress Relaxation ◽

Hybrid Polymer Composite

Polymer composites have a characteristic, composition specific visco-elastic property which influences the damage progression during fatigue cycling. While some researchers have studied the time dependent constitutive response of polymer composites during the first cycle of fatigue loading, very few have experimentally investigated the dependence of visco-elastic response of built-up polymer composite materials at various stages of fatigue cycling [1]. Our earlier studies on fatigue response of polymer composites focused primarily on the stiffness degradation as a function of applied cycles of loading, which represents the gross response of the material [2]. While doing such an experiment, complimentary experimental techniques to measure the temperature evolution was attempted through the use of infrared thermal imaging technique, which gave some insight into the change in temperature response as a function of fatigue cycling. However, there was no systematic measurement of creep and stress relaxation response of the composite material as a function of induced fatigue damage. The present paper describes the results of creep and stress-relaxation obtained during uni-axial fatigue loading of a hybrid polymer composite material. For this purpose, a woven carbon fiber mat was chosen as the synthetic fiber and Flax fiber in the unidirectional form was chosen as the natural fiber that is laid between the two layers of woven carbon fiber mat. Epoxy LY 556 and hardener Araldite® was used for building up of composite laminate by hand-lay-up technique. Dog-bone shaped tensile specimens with a gage width of 13 mm and gage length of 57 mm were extracted from the 250 × 250 mm sq. plate laminate of 2.1 mm thickness using a numerical controlled milling machine. The specimens were tested at 35% of their median tensile strengths under fatigue at a positive stress ratio (Pmin/Pmax) of 0.1 in tension-tension loading. Prior to start of fatigue loading, the specimens were held in load control and the strain in the gage length was measured for understanding the creep response over 2500 seconds. For stress-relaxation characterization, the specimens were held in extensometer control over a period of 2500 sec. The creep and stress relaxation tests were carried out after periodic intervals of fatigue cycling. It was observed that in the case of un-impacted specimens, the creep rate is consistent with the stiffness variation, which in turn, is dependent on the number of fatigue cycles - till it showed signs of de-lamination. Thereafter it was governed by the woven synthetic fiber response. Similarly, the stress relaxation response was found to decrease with increasing fatigue cycles. In case of impacted specimens, the local deformation had a prominent role in terms of creep and stress relaxation response.

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New therapeutic patents used for the treatment of leprosy: a review

Epidemiology and Infection ◽

10.1017/s0950268818002145 ◽

2018 ◽

Vol 146 (14) ◽

pp. 1746-1749 ◽

Cited By ~ 2

Author(s):

Nayara Gomes Lima Santos ◽

Karen Perez Pereira Ramos ◽

Saravanan Shanmugam ◽

Fernanda Oliveira de Carvalho ◽

Luciana Garcez Barreto Teixeira ◽

...

Keyword(s):

Peripheral Nerves ◽

Peripheral Neuropathies ◽

Loss Of Function ◽

Cutaneous Lesions ◽

Patent Classification ◽

Human Needs ◽

International Patent ◽

Different Types ◽

New Treatment

AbstractLeprosy is a granulomatous disease, infectious and transmissible, which affects the skin and peripheral nerves, havingMycobacterium lepraeas causative agent. The manifestation of this disease causes cutaneous lesions, peripheral neuropathies and, in more extreme cases, may generate deformities and disabilities in affected individuals. Patents were identified using the descriptor ‘leprosy’ and code A61K of the international patent classification, which indicates only products that meet human needs. The analysis was made using theWIPO,ESPACENETandUSPTOdatabases, until the month of September 2016. Through this review, we found a variety of in vitro, pre-clinical and clinical studies relating to the treatment of leprosy with different types of compounds and forms of administration. New treatment proposals should include pain reduction capabilities, prevention or limitation of the appearance of cutaneous lesions, as well as prevention of the progression of the disease to more severe stages that may lead to loss of function or potentiate the individual's immune response to theM. lepraebacillus in order to prevent bacterial spread. We concluded that any patents developed with natural products were not found in the treatment of leprosy. All the deposited products were synthetic origin, mostly tested in humans and of varied forms of administration.

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