scholarly journals Fluoride Treatment and In Vitro Corrosion Behavior of Mg-Nd-Y-Zn-Zr Alloys Type

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 566
Author(s):  
Pham Hong Quan ◽  
Iulian Antoniac ◽  
Florin Miculescu ◽  
Aurora Antoniac ◽  
Veronica Manescu (Păltânea) ◽  
...  
Keyword(s):  
Corrosion Behavior ◽  
Orthopedic Implants ◽  
Immersion Test ◽  
Nacl Solution ◽  
Fluoride Ions ◽  
Fluoride Treatment ◽  
Cardiovascular Stents ◽  
Before And After

Fluoride conversion coatings on Mg present many advantages, among which one can find the reduction of the corrosion rate under “in vivo” or “in vitro” conditions and the promotion of the calcium phosphate deposition. Moreover, the fluoride ions released from MgF2 do not present cytotoxic effects and inhibit the biofilm formation, and thus these treated alloys are very suitable for cardiovascular stents and biodegradable orthopedic implants. In this paper, the biodegradation behavior of four new magnesium biodegradable alloys that have been developed in the laboratory conditions, before and after surface modifications by fluoride conversion (and sandblasting) coatings, are analyzed. We performed structural and surface analysis (XRD, SEM, contact angle) before and after applying different surface treatments. Furthermore, we studied the electrochemical behavior and biodegradation of all experimental samples after immersion test performed in NaCl solution. For a better evaluation, we also used LM and SEM for evaluation of the corroded samples after immersion test. The results showed an improved corrosion resistance for HF treated alloy in the NaCl solution. The chemical composition, uniformity, thickness and stability of the layers generated on the surface of the alloys significantly influence their corrosion behavior. Our study reveals that HF treatment is a beneficial way to improve the biofunctional properties required for the studied magnesium alloys to be used as biomaterials for manufacturing the orthopedic implants.

scholarly journals The Effect of Physiological Incubation on the Properties of Elastic Magnetic Composites for Soft Biomedical Sensors

Sensors ◽  
2021 ◽  
Vol 21 (21) ◽  
pp. 7122
Author(s):  
Joanna Mystkowska ◽  
Anna Powojska ◽  
Dawid Łysik ◽  
Joanna Niewęgłowska ◽  
Gilbert Santiago Cañón Bermúdez ◽  
...  
Keyword(s):  
Point Of View ◽  
Nacl Solution ◽  
Magnetic Composites ◽  
Biomedical Sensors ◽  
Before And After ◽  
Properties Of Materials ◽  
Positive Effect ◽  
Comprehensive Study

Magnetic micro- and nanoparticles (MPs)-based composite materials are widely used in various applications in electronics, biotechnology, and medicine. This group of silicone composites have advantageous magnetic and mechanical properties as well as sufficient flexibility and biocompatibility. These composites can be applied in medicine for biological sensing, drug delivery, tissue engineering, and as remote-controlled microrobots operating in vivo. In this work, the properties of polydimethylsiloxane (PDMS)-based composites with different percentages (30 wt.%, 50 wt.%, 70 wt.%) of NdFeB microparticles as a filler were characterized. The novelty of the work was to determine the influence of the percentage of MP content and physiological conditioning on the properties of the PDMS-MP composites after in vitro incubation. An important essence of the work was a comprehensive study of the properties of materials important from the point of view of medical applications. Materials were tested before and after conditioning in 0.9 wt.% NaCl solution at a temperature of 37 °C. Several studies were carried out, including thermal, physicochemical, and rheological tests. The results show that with an increase of the incubation time, most of the measured thermal and physicochemical parameters decreased. The presence of the magnetic filler, especially at a concentration of 70 wt.%, has a positive effect on thermal stability and physicochemical and rheological properties. The performed tests provided important results, which can lead to further research for a broader application of magnetic composites in the biomedical field.

Radiolabeled r-Hirudin as a Measure of Thrombin Activity at, or within, the Rabbit Aorta Wall In Vitro and In Vivo

1994 ◽  
Vol 71 (04) ◽  
pp. 499-506 ◽  
Author(s):  
Mark W C Hatton ◽  
Bonnie Ross-Ouellet
Keyword(s):  
Rabbit Aorta ◽  
Balloon Injury ◽  
Recombinant Hirudin ◽  
Aorta Wall ◽  
Thrombin Activity ◽  
Before And After ◽  
The Matrix

SummaryThe behavior of 125I-labeled recombinant hirudin towards the uninjured and de-endothelialized rabbit aorta wall has been studied in vitro and in vivo to determine its usefulness as an indicator of thrombin activity associated with the aorta wall. Thrombin adsorbed to either sulfopropyl-Sephadex or heparin-Sepharose bound >95% of 125I-r-hirudin and the complex remained bound to the matrix. Binding of 125I-r-hirudin to the exposed aorta subendothelium (intima-media) in vitro was increased substantially if the tissue was pre-treated with thrombin; the quantity of l25I-r-hirudin bound to the de-endothelialized intima-media (i.e. balloon-injured in vitro) correlated positively with the quantity of bound 131I-thrombin (p <0.01). Aortas balloon-injured in vivo were measured for thrombin release from, and binding of 125I-r-hirudin to, the de-endothelialized intimal surface in vitro; 125I-r-hirudin binding correlated with the amount of active thrombin released (p <0.001). Uptake of 125I-r-hirudin by the aorta wall in vivo was proportional to the uptake of 131I-fibrinogen (as an indicator of thrombin activity) before and after balloon injury. After 30 min in the circulation, specific 125I-r-hirudin binding to the uninjured and de-endo- thelialized (at 1.5 h after injury) aorta wall was equivalent to 3.4 (± 2.5) and 25.6 (±18.1) fmol of thrombin/cm2 of intima-media, respectively. Possibly, only hirudin-accessible, glycosaminoglycan-bound thrombin is measured in this way.

scholarly journals miR-146a-5p Promotes Chondrocyte Apoptosis and Inhibits Autophagy of Osteoarthritis by Targeting NUMB

Cartilage ◽  
2021 ◽  
pp. 194760352110235
Author(s):  
Hongjun Zhang ◽  
Wendi Zheng ◽  
Du Li ◽  
Jia Zheng
Keyword(s):  
Caspase 3 ◽  
Cartilage Tissue ◽  
Luciferase Reporter ◽  
Chondrocyte Apoptosis ◽  
Knee Cartilage ◽  
Before And After ◽  
Related Proteins ◽  
Human And Mouse

Objective miR-146a-5p was found to be significantly upregulated in cartilage tissue of patients with osteoarthritis (OA). NUMB was shown to be involved in the autophagy regulation process of cells. We aimed to learn whether NUMB was involved in the apoptosis or autophagy process of chondrocytes in OA and related with miR-146a-5p. Methods QRT-PCR was used to detect miR-146a-5p level in 22 OA cartilage tissues and 22 controls. The targets of miR-146a-5p were analyzed using software and the luciferase reporter experiment. The apoptosis and autophagy, and related proteins were detected in chondrocytes treated with miR-146a-5p mimic/inhibitor or pcDNA3.1-NUMB/si-NUMB and IL-1β, respectively. In vivo experiment, intra-articular injection of miR-146a-5p antagomir/NC was administered at the knee of OA male mice before and after model construction. Chondrocyte apoptosis and the expression of apoptosis and autophagy-related proteins were also detected. Results miR-146a-5p was highly expressed in knee cartilage tissue of patients with OA, while NUMB was lowly expressed and negatively regulated by miR-146a-5p. Upregulation of miR-146a-5p can promote cell apoptosis and reduce autophagy of human and mouse chondrocytes by modulating the levels of cleaved caspase-3, cleaved PARP, Bax, Beclin 1, ATG5, p62, LC3-I, and LC3-II. Increasing the low level of NUMB reversed the effects of miR-146a-5p on chondrocyte apoptosis and autophagy. Intra-articular injection of miR-146a-5p antagomir can also reverse the effects of miR-146a-5p on the apoptosis and autophagy of knee joint chondrocytes in OA mice. Conclusion Downregulation of miR-146a-5p suppresses the apoptosis and promotes autophagy of chondrocytes by targeting NUMB in vivo and in vitro.

scholarly journals Detection of Anthrax Toxin in the Serum of Animals Infected with Bacillus anthracis by Using Engineered Immunoassays

2006 ◽  
Vol 13 (6) ◽  
pp. 671-677 ◽  
Author(s):  
Robert Mabry ◽  
Kathleen Brasky ◽  
Robert Geiger ◽  
Ricardo Carrion ◽  
Gene B. Hubbard ◽  
...  
Keyword(s):  
Bacillus Anthracis ◽  
Protective Antigen ◽  
Lethal Factor ◽  
Systemic Circulation ◽  
Rapid Identification ◽  
Anthrax Toxin ◽  
Soluble Form ◽  
Before And After

ABSTRACT Several strategies that target anthrax toxin are being developed as therapies for infection by Bacillus anthracis. Although the action of the tripartite anthrax toxin has been extensively studied in vitro, relatively little is known about the presence of toxins during an infection in vivo. We developed a series of sensitive sandwich enzyme-linked immunosorbent assays (ELISAs) for detection of both the protective antigen (PA) and lethal factor (LF) components of the anthrax exotoxin in serum. The assays utilize as capture agents an engineered high-affinity antibody to PA, a soluble form of the extracellular domain of the anthrax toxin receptor (ANTXR2/CMG2), or PA itself. Sandwich immunoassays were used to detect and quantify PA and LF in animals infected with the Ames or Vollum strains of anthrax spores. PA and LF were detected before and after signs of toxemia were observed, with increasing levels reported in the late stages of the infection. These results represent the detection of free PA and LF by ELISA in the systemic circulation of two animal models exposed to either of the two fully virulent strains of anthrax. Simple anthrax toxin detection ELISAs could prove useful in the evaluation of potential therapies and possibly as a clinical diagnostic to complement other strategies for the rapid identification of B. anthracis infection.

Tracings of Behavior of Myoblasts Cultured Under Couette Type of Shear Flow Between Parallel Disks

2021 ◽  
Author(s):  
Shigehiro Hashimoto ◽  
Hiroki Yonezawa
Keyword(s):  
Shear Stress ◽  
Shear Flow ◽  
Rotating Disk ◽  
Time Lapse ◽  
Mechanical Stimuli ◽  
Parallel Disks ◽  
Before And After ◽  
A Cell

Abstract A cell deforms and migrates on the scaffold under mechanical stimuli in vivo. In this study, a cell with division during shear stress stimulation has been observed in vitro. Before and after division, both migration and deformation of each cell were analyzed. To make a Couette-type shear flow, the medium was sandwiched between parallel disks (the lower stationary culture-disc and the upper rotating disk) with a constant gap. The wall shear stress (1.5 Pa &lt; τ &lt; 2 Pa) on the surface of the lower culture plate was controlled by the rotational speed of the upper disc. Myoblasts (C2C12: mouse myoblast cell line) were used in the test. After cultivation without flow for 24 hours for adhesion of the cells to the lower disk, constant τ was applied to the cells in the incubator for 7 days. The behavior of each cell during shear was tracked by time-lapse images observed by an inverted phase contrast microscope placed in the incubator. Experimental results show that each cell tends to divide after higher activities: deformation and migration. The tendency is remarkable at the shear stress of 1.5 Pa.

Fistulous-type vein of Galen malformation phantom model for endovascular training and research

2016 ◽  
Vol 9 (9) ◽  
pp. 880-886
Author(s):  
Dan Meila ◽  
Katharina Melber ◽  
Dominik Grieb ◽  
Collin Jacobs ◽  
Heinrich Lanfermann ◽  
...  
Keyword(s):  
Treatment Options ◽  
Endovascular Embolization ◽  
High Flow ◽  
Vein Of Galen ◽  
Vein Of Galen Malformation ◽  
Phantom Model ◽  
Before And After ◽  
And Training

IntroductionVein of Galen malformation (VGM), a high-flow intracranial arteriovenous shunt, is among the most severe neurovascular diseases in childhood. In many cases untreated children die or survive only severely disabled. Endovascular embolization is the preferred treatment.ObjectiveTo develop a simple fistulous-type VGM phantom model for teaching and training of different endovascular treatment methods and to investigate new treatment options and devices.MethodsAn experimental in vitro pulsatile phantom model was developed imitating a high-flow fistulous-type VGM, which is typical, especially in the neonatal phase. Pressure measurements at different arterial sites were performed before and after closure of the VGM. Closure of the VGM was achieved by coiling using a combined microcatheter-based transvenous and transarterial approach called ‘kissing microcatheter technique’.ResultsThe behaviour of the phantom model in vitro under fluoroscopy and under angiographic runs was extremely similar to that in in vivo conditions in children. The results showed that intra-arterial pressures changed and increased statistically significantly at all measurement sites after embolization, as in human arteriovenous malformation. We also demonstrated different and complementary visualizations of hemodynamics and angioarchitecture by antegrade and retrograde microcatheter injections.ConclusionsOur phantom model behaves like a typical fistulous-type VGM and can be used in vitro for teaching and training and for further research. It offers a new and better understanding of hemodynamics and angioarchitecture in the endovascular management of VGM.

scholarly journals In vivo hypotensive effect and in vitro inhibitory activity of some Cyperaceae species

2013 ◽  
Vol 49 (4) ◽  
pp. 803-809
Author(s):  
Monica Lacerda Lopes Martins ◽  
Henrique Poltronieri Pacheco ◽  
Iara Giuberti Perini ◽  
Dominik Lenz ◽  
Tadeu Uggere de Andrade ◽  
...  
Keyword(s):  
Inhibitory Activity ◽  
Colorimetric Assay ◽  
Hypotensive Effect ◽  
Ace Inhibition ◽  
Inhibitory Effect ◽  
Positive Control ◽  
Total Phenolic ◽  
Before And After

In 1820, French naturalist August Saint Hillaire, during a visit in Espírito Santo (ES), a state in southeastern Brazil, reported a popular use of Cyperaceae species as antidote to snake bites. The plant may even have a hypotensive effect, though it was never properly researched. The in vitro inhibitory of the angiotensin converting enzyme (ACE) activity of eigth ethanolic extracts of Cyperaceae was evaluated by colorimetric assay. Total phenolic and flavonoids were determined using colorimetric assay. The hypotensive effect of the active specie (Rhychonospora exaltata, ERE) and the in vivo ACE assay was measured in vivo using male Wistar Kyoto (ERE, 0.01-100mg/kg), with acetylcholine (ACh) as positive control (5 µg/kg, i.v.). The evaluation of ACE in vivo inhibitory effect was performed comparing the mean arterial pressure before and after ERE (10 mg/kg) in animals which received injection of angiotensin I (ANG I; 0,03, 03 and 300 µg/kg, i.v.). Captopril (30 mg/kg) was used as positive control. Bulbostylis capillaris (86.89 ± 15.20%) and ERE (74.89 ± 11.95%, ERE) were considered active in the in vitro ACE inhibition assay, at 100 µg/mL concentration. ACh lead to a hypotensive effect before and after ERE's curve (-40±5% and -41±3%). ERE showed a dose-dependent hypotensive effect and a in vivo ACE inhibitory effect. Cyperaceae species showed an inhibitory activity of ACE, in vitro, as well as high content of total phenolic and flavonoids. ERE exhibited an inhibitory effect on both in vitro and in vivo ACE. The selection of species used in popular medicine as antidotes, along with the in vitro assay of ACE inhibition, might be a biomonitoring method for the screening of new medicinal plants with hypotensive properties.

scholarly journals Protein oligomerization is the biochemical process highly up-regulated in porcine oocytes before in vitro maturation (IVM)

2018 ◽  
Vol 6 (4) ◽  
pp. 155-162 ◽  
Author(s):  
Sylwia Borys-Wójcik ◽  
Ievgenia Kocherova ◽  
Piotr Celichowski ◽  
Małgorzata Popis ◽  
Michal Jeseta ◽  
...  
Keyword(s):  
In Vitro Maturation ◽  
Protein Oligomerization ◽  
Dynamic Nature ◽  
Affymetrix Microarray ◽  
Expression Of Genes ◽  
Before And After ◽  
Porcine Oocyte ◽  
Lower Expression

AbstractA wide variety of mechanisms controlling oligomerization are observed. The dynamic nature of protein oligomerization is important for bioactivity control. The oocyte must undergo a series of changes to become a mature form before it can fully participate in the processes associated with its function as a female gamete. The growth of oocytes in the follicular environment is accompanied by surrounding somatic cumulus (CCs) and granulosa cells (GCs). It has been shown that oocytes tested before and after in vitro maturation (IVM) differ significantly in the transcriptomic and proteomic profiles. The aim of this study was to determine new proteomic markers for the oligomerization of porcine oocyte proteins that are associated with cell maturation competence. The Affymetrix microarray assay was performed to examine the gene expression profile associated with protein oligomerization in oocytes before and after IVM. In total, 12258 different transcriptomes were analyzed, of which 419 genes with lower expression in oocytes after IVM. We found 9 genes: GJA1, VCP, JUP, MIF, MAP3K1, INSR, ANGPTL4, EIF2AK3, DECR1, which were significantly down-regulated in oocytes after IVM (in vitro group) compared to oocytes analyzed before IVM (in vivo group). The higher expression of genes involved in the oligomerization of the protein before IVM indicates that they can be recognized as important markers of biological activation of proteins necessary for the further growth and development of pig embryos.

scholarly journals Modeling glioblastoma invasion using human brain organoids and single-cell transcriptomics

2019 ◽  
Author(s):  
Teresa G Krieger ◽  
Stephan M Tirier ◽  
Jeongbin Park ◽  
Tanja Eisemann ◽  
Heike Peterziel ◽  
...  
Keyword(s):  
Single Cell ◽  
Specific Treatment ◽  
Cellular Heterogeneity ◽  
Patient Specific ◽  
Before And After ◽  
Invasive Capacity ◽  
Transcriptional Changes ◽  
Potential Interactions

AbstractGlioblastoma multiforme (GBM) are devastating neoplasms with high invasive capacity. GBM has been difficult to study in vitro. Therapeutic progress is also limited by cellular heterogeneity within and between tumors. To address these challenges, we present an experimental model using human cerebral organoids as a scaffold for patient-derived glioblastoma cell invasion. By tissue clearing and confocal microscopy, we show that tumor cells within organoids extend a network of long microtubes, recapitulating the in vivo behavior of GBM. Single-cell RNA-seq of GBM cells before and after co-culture with organoid cells reveals transcriptional changes implicated in the invasion process that are coherent across patient samples, indicating that GBM cells reactively upregulate genes required for their dispersion. Functional therapeutic targets are identified by an in silico receptor-ligand pairing screen detecting potential interactions between GBM and organoid cells. Taken together, our model has proven useful for studying GBM invasion and transcriptional heterogeneity in vitro, with applications for both pharmacological screens and patient-specific treatment selection at a time scale amenable to clinical practice.

scholarly journals Electrodeposited Platinum Iridium Enables Microstimulation With Carbon Fiber Electrodes

2021 ◽  
Vol 3 ◽  
Author(s):  
Elena della Valle ◽  
Beomseo Koo ◽  
Paras R. Patel ◽  
Quentin Whitsitt ◽  
Erin K. Purcell ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Cross Sections ◽  
Minimal Scarring ◽  
Pulse Testing ◽  
Implant Tests ◽  
Before And After ◽  
Voltage Transients ◽  
Scanning Electron

Ultrasmall microelectrode arrays have the potential to improve the spatial resolution of microstimulation. Carbon fiber (CF) microelectrodes with cross-sections of less than 8 μm have been demonstrated to penetrate cortical tissue and evoke minimal scarring in chronic implant tests. In this study, we investigate the stability and performance of neural stimulation electrodes comprised of electrodeposited platinum-iridium (PtIr) on carbon fibers. We conducted pulse testing and characterized charge injection in vitro and recorded voltage transients in vitro and in vivo. Standard electrochemical measurements (impedance spectroscopy and cyclic voltammetry) and visual inspection (scanning electron microscopy) were used to assess changes due to pulsing. Similar to other studies, the application of pulses caused a decrease in impedance and a reduction in voltage transients, but analysis of the impedance data suggests that these changes are due to surface modification and not permanent changes to the electrode. Comparison of scanning electron microscope images before and after pulse testing confirmed electrode stability.

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