scholarly journals Application of Ultrasound on Monitoring the Evolution of the Collagen Fiber Reinforced nHAC/CS CompositesIn Vivo

2014 ◽  
Vol 2014 ◽  
pp. 1-9
Author(s):  
Yan Chen ◽  
Yuting Yan ◽  
Xiaoming Li ◽  
He Li ◽  
Huiting Tan ◽  
...  
Keyword(s):  
Collagen Fiber ◽  
Soft Tissues ◽  
Degradation Process ◽  
Ultrasound Images ◽  
Fiber Reinforced ◽  
Bone Mesenchymal Stem Cells ◽  
Feasible Alternative ◽  
The Impact

To date, fiber reinforce scaffolds have been largely applied to repair hard and soft tissues. Meanwhile, monitoring the scaffolds for long periodsin vivois recognized as a crucial issue before its wide use. As a consequence, there is a growing need for noninvasive and convenient methods to analyze the implantation remolding processin situand in real time. In this paper, diagnostic medical ultrasound was used to monitor thein vivobone formation and degradation process of the novel mineralized collagen fiber reinforced composite which is synthesized by chitosan (CS), nanohydroxyapatite (nHA), and collagen fiber (Col). To observe the impact of cells on bone remodeling process, the scaffolds were planted into the back of the SD rats with and without rat bone mesenchymal stem cells (rBMSCs). Systematic data of scaffoldsin vivowas extracted from ultrasound images. Significant consistency between the data from the ultrasound and DXA could be observedP<0.05. This indicated that ultrasound may serve as a feasible alternative for noninvasive monitoring the evolution of scaffoldsin situduring cell growth.

Vascular permeability alterations induced by arsenic

2004 ◽  
Vol 23 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Shih-Chieh Chen ◽  
Ming-Hsien Tsai ◽  
Hsiu-Jen Wang ◽  
Hsin-Su Yu ◽  
Louis W Chang
Keyword(s):  
Vascular Permeability ◽  
Evans Blue ◽  
Graphite Furnace ◽  
Vascular Leakage ◽  
Arsenic Content ◽  
India Ink ◽  
The Impact ◽  
In Situ Exposure

The impact of arsenic on the integrity of blood vessels in vivo via in situ exposure (local injection) of arsenic was investigated. Vascular permeability changes were evaluated by means of the Evans blue assay and the India ink tracer techniques. Rats were intravenously injected with Evans blue followed by intradermal injections of various doses of sodium arsenite on the back skins of the animals. Evans blue at different time points was extracted and assayed as indices of vascular leakage. Skin at various time point injection sites was sampled for arsenic measurement via graphite furnace atomic absorption spectroscopy. Our time course study with Evans blue technique demonstrated a biphasic pattern of vascular permeability change: an early phase of permeability reduction and a later phase of permeability promotion at all dose levels tested. The India ink tracer technique also demonstrated a time-correlated increase in vascular labelling in the tissues examined, signifying an increase in vascular leakage with time. Moreover, we found that despite an early increase in tissue arsenic content at time of injection, tissue arsenic declined rapidly and returned to near control levels after 30-60 min. Thus, an inverse correlation between tissue arsenic content and the extent of vascular permeability was apparent. This study provides the first demonstration that in situ exposure to arsenic will produce vascular dysfunction (vascular leakage) in vivo.

Effect of superelastic shape memory alloy wires on the impact behavior of carbon fiber reinforced in situ polymerized poly(butylene terephthalate) composites

2011 ◽  
Vol 65 (5) ◽  
pp. 863-865 ◽  
Author(s):  
J. Aurrekoetxea ◽  
J. Zurbitu ◽  
I. Ortiz de Mendibil ◽  
A. Agirregomezkorta ◽  
M. Sánchez-Soto ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Impact Behavior ◽  
Fiber Reinforced ◽  
Butylene Terephthalate ◽  
Carbon Fiber Reinforced ◽  
The Impact

scholarly journals Effect of fiber crosslinking on collagen-fiber reinforced collagen-chondroitin-6-sulfate materials for regenerating load-bearing soft tissues

2012 ◽  
Vol 101A (1) ◽  
pp. 176-184 ◽  
Author(s):  
J. H. Shepherd ◽  
S. Ghose ◽  
S. J. Kew ◽  
A. Moavenian ◽  
S. M. Best ◽  
...  
Keyword(s):  
Collagen Fiber ◽  
Soft Tissues ◽  
Fiber Reinforced ◽  
Load Bearing

scholarly journals Phagocytosis and Efferocytosis by Resident Macrophages in the Mouse Pancreas

2021 ◽  
Vol 12 ◽  
Author(s):  
Kristel Parv ◽  
Nestori Westerlund ◽  
Kevin Merchant ◽  
Milad Komijani ◽  
Robin S. Lindsay ◽  
...  
Keyword(s):  
Confocal Imaging ◽  
Mouse Pancreas ◽  
Tissue Microenvironment ◽  
Inflammatory State ◽  
Islet Dysfunction ◽  
Diabetes Development ◽  
The Impact

The tissue microenvironment in the mouse pancreas has been shown to promote very different polarizations of resident macrophages with islet-resident macrophages displaying an inflammatory “M1” profile and macrophages in the exocrine tissue mostly displaying an alternatively activated “M2” profile. The impact of this polarization on tissue homeostasis and diabetes development is unclear. In this study, the ability of pancreas-resident macrophages to phagocyte bacterial and endogenous debris was investigated. Mouse endocrine and exocrine tissues were separated, and tissue-resident macrophages were isolated by magnetic immunolabeling. Isolated macrophages were subjected to flow cytometry for polarization markers and qPCR for phagocytosis-related genes. Functional in vitro investigations included phagocytosis and efferocytosis assays using pH-sensitive fluorescent bacterial particles and dead fluorescent neutrophils, respectively. Intravital confocal imaging of in situ phagocytosis and efferocytosis in the pancreas was used to confirm findings in vivo. Gene expression analysis revealed no significant overall difference in expression of most phagocytosis-related genes in islet-resident vs. exocrine-resident macrophages included in the analysis. In this study, pancreas-resident macrophages were shown to differ in their ability to phagocyte bacterial and endogenous debris depending on their microenvironment. This difference in abilities may be one of the factors polarizing islet-resident macrophages to an inflammatory state since phagocytosis has been found to imprint macrophage heterogeneity. It remains unclear if this difference has any implications in the development of islet dysfunction or autoimmunity.

scholarly journals Mechanical Response Changes in Porcine Tricuspid Valve Anterior Leaflet Under Osmotic-Induced Swelling

2019 ◽  
Vol 6 (3) ◽  
pp. 70 ◽  
Author(s):  
Samuel D. Salinas ◽  
Margaret M. Clark ◽  
Rouzbeh Amini
Keyword(s):  
Tricuspid Valve ◽  
Soft Tissues ◽  
Mechanical Response ◽  
Ex Vivo ◽  
Control Group ◽  
Anterior Leaflet ◽  
Buffer Solution ◽  
Tissue Samples ◽  
The Impact

Since many soft tissues function in an isotonic in-vivo environment, it is expected that physiological osmolarity will be maintained when conducting experiments on these tissues ex-vivo. In this study, we aimed to examine how not adhering to such a practice may alter the mechanical response of the tricuspid valve (TV) anterior leaflet. Tissue specimens were immersed in deionized (DI) water prior to quantification of the stress–strain responses using an in-plane biaxial mechanical testing device. Following a two-hour immersion in DI water, the tissue thickness increased an average of 107.3% in the DI water group compared to only 6.8% in the control group, in which the tissue samples were submerged in an isotonic phosphate buffered saline solution for the same period of time. Tissue strains evaluated at 85 kPa revealed a significant reduction in the radial direction, from 34.8% to 20%, following immersion in DI water. However, no significant change was observed in the control group. Our study demonstrated the impact of a hypo-osmotic environment on the mechanical response of TV anterior leaflet. The imbalance in ions leads to water absorption in the valvular tissue that can alter its mechanical response. As such, in ex-vivo experiments for which the native mechanical response of the valves is important, using an isotonic buffer solution is essential.

scholarly journals A Method for Predicting Collagen Fiber Realignment in Non-Planar Tissue Surfaces as Applied to Glenohumeral Capsule During Clinically Relevant Deformation

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Rouzbeh Amini ◽  
Carrie A. Voycheck ◽  
Richard E. Debski
Keyword(s):  
Collagen Fiber ◽  
Soft Tissues ◽  
Deformation Gradient ◽  
Experimental Methods ◽  
New Method ◽  
Fiber Distribution ◽  
Tissue Surfaces ◽  
3D Deformation ◽  
Glenohumeral Capsule

Previously developed experimental methods to characterize micro-structural tissue changes under planar mechanical loading may not be applicable for clinically relevant cases. Such limitation stems from the fact that soft tissues, represented by two-dimensional surfaces, generally do not undergo planar deformations in vivo. To address the problem, a method was developed to directly predict changes in the collagen fiber distribution of nonplanar tissue surfaces following 3D deformation. Assuming that the collagen fiber distribution was known in the un-deformed configuration via experimental methods, changes in the fiber distribution were predicted using 3D deformation. As this method was solely based on kinematics and did not require solving the stress balance equations, the computational efforts were much reduced. In other words, with the assumption of affine deformation, the deformed collagen fiber distribution was calculated using only the deformation gradient tensor (obtained via an in-plane convective curvilinear coordinate system) and the associated un-deformed collagen fiber distribution. The new method was then applied to the glenohumeral capsule during simulated clinical exams. To quantify deformation, positional markers were attached to the capsule and their 3D coordinates were recorded in the reference position and three clinically relevant joint positions. Our results showed that at 60deg of external rotation, the glenoid side of the posterior axillary pouch had significant changes in fiber distribution in comparison to the other sub-regions. The larger degree of collagen fiber alignment on the glenoid side suggests that this region is more prone to injury. It also compares well with previous experimental and clinical studies indicating maximum principle strains to be greater on the glenoid compared to the humeral side. An advantage of the new method is that it can also be easily applied to map experimentally measured collagen fiber distribution (obtained via methods that require flattening of tissue) to their in vivo nonplanar configuration. Thus, the new method could be applied to many other nonplanar fibrous tissues such as the ocular shell, heart valves, and blood vessels.

scholarly journals Modeling Fatigue Damage in Chemically Treated Soft Tissues

2000 ◽  
Author(s):  
William S. Slaughter ◽  
Michael S. Sacks
Keyword(s):  
Mechanical Properties ◽  
Fatigue Damage ◽  
Chemical Treatment ◽  
Damage Mechanics ◽  
Collagen Fiber ◽  
Soft Tissues ◽  
Cardiac Valve ◽  
Chemically Treated ◽  
Treatment Technologies ◽  
The Impact

Abstract Chemically treated, biologically derived tissues are used extensively in cardiac valve bioprostheses. Unfortunately, while extensive research has focused on chemical treatment technologies to reduce negative in-vivo effects such as mineralization and to enhance overall biocompatibility, little work has been done on understanding the effects of fatigue on tissue mechanical properties. In the current work, a structure-based damage mechanics model for the evolution of mechanical properties with cyclic loading of chemically treated soft tissues is presented. The model is used to clarify and relate the impact of different structural changes, such as collagen fiber debonding and collagen fiber weakening, to changes in macro-level tissue mechanical properties. The fatigue damage model will ultimately serve as a guide for the development of key experiments for fatigue damage assessment of novel chemical treatment technologies. This will aid in the rational development, as opposed to the current ad-hoc approach, of novel chemically modified collagenous biomaterials for more durable cardiac valve bioprostheses.

scholarly journals Thermo-Responsive Hydrogels Based on Methylcellulose/Persian Gum Loaded With Taxifolin Enhance Bone Regeneration: An in Vitro / in Vivo Study

2021 ◽  
Author(s):  
Zahra Sadat Sajadi-Javan ◽  
Jaleh Varshosaz ◽  
Mina Mirian ◽  
Maziar Manshaei ◽  
Atousa Aminzadeh
Keyword(s):  
Animal Studies ◽  
Bone Defects ◽  
Halloysite Nanotubes ◽  
Thermosensitive Hydrogel ◽  
Alizarin Red ◽  
The Impact ◽  
Responsive Hydrogels

Abstract In-situ forming hydrogels have gained noticeable attention to encapsulate osteogenic agents and regenerate irregular-shape bone defects. In this study, a novel thermosensitive hydrogel based on blended methylcellulose (MC) with Persian gum (PG) was fabricated and enriched with taxifolin (TAX) loaded halloysite nanotubes (HNTs) to enhance mechanical and biological characteristics of the hydrogel in bone tissue engineering. The injectability, mechanical and rheological tests were performed for different hydrogel formulations containing 0.25-1.5 w/v% PG and 1-7 w/v% HNTs. Also, to evaluate the impact of PG and HNTs on hydrogel behavior, the degradation rate and swelling degree of hydrogels were assessed. The optimized MC/PG/HNTs hydrogel containing 1% PG and 3% HNTs (MC/PG-1/HNTs 3%) was easily injectable and gelled rapidly at physiological temperature, while it had the highest mechanical strength due to the existence of PG and HNTs. In vitro release study of TAX from this system also revealed more sustained release compared to HNTs-TAX nanoparticles. Furthermore, the interaction of cells with hydrogel and osteo-conductivity was studied using osteoblast-like cells (MG-63). Results showed higher cell adhesion, proliferation, and gene expression for MC/PG-1/HNTs-TAX hydrogel compared to MC/PG-1 and MC/PG-1/HNTs 3% possibly due to the synergic effect of HNTs and TAX. In addition, Alizarin Red S staining and alkaline phosphatase measurements indicated that the existence of HNTs-TAX promoted osteogenic differentiation. Eventually, animal studies on the femoral defects indicated improved remedy when using the MC/PG-1/HNTs-TAX hydrogel carrying MG-63 cells.

Does Finishing and Polishing of Restorative Materials Affect Bacterial Adhesion and Biofilm Formation? A Systematic Review

2018 ◽  
Vol 43 (1) ◽  
pp. E37-E52 ◽  
Author(s):  
DAM Dutra ◽  
GKR Pereira ◽  
KZ Kantorski ◽  
LF Valandro ◽  
FB Zanatta
Keyword(s):  
Systematic Review ◽  
Bacterial Adhesion ◽  
Biofilm Formation ◽  
Surface Characteristics ◽  
Periodontal Inflammation ◽  
Restorative Materials ◽  
The Impact

SUMMARY Biofilm (bacterial plaque) accumulation on the surface of restorative materials favors the occurrence of secondary caries and periodontal inflammation. Surface characteristics of restorations can be modified by finishing and/or polishing procedures and may affect bacterial adhesion. The aim of this systematic review was to characterize how finishing and polishing methods affect the surface properties of different restorative materials with regard to bacterial adhesion and biofilm formation. Searches were carried out in MEDLINE-PubMed, EMBASE, Cochrane-CENTRAL, and LILACS databases. From 2882 potential articles found in the initial searches, only 18 met the eligible criteria and were included in this review (12 with in vitro design, four with in situ design, and two clinical trials). However, they presented high heterogeneity regarding materials considered and methodology for evaluating the desired outcome. Risk bias analysis showed that only two studies presented low risk (whereas 11 showed high and five showed medium risk). Thus, only descriptive analyses considering study design, materials, intervention (finishing/polishing), surface characteristics (roughness and surface free energy), and protocol for biofilm formation (bacterial adhesion) could be performed. Some conclusions could be drawn: the impact of roughness on bacterial adhesion seems to be related not to a roughness threshold (as previously believed) but rather to a range, the range of surface roughness among different polishing methods is wide and material dependent, finishing invariably creates a rougher surface and should always be followed by a polishing method, each dental material requires its own treatment modality to obtain and maintain as smooth a surface as possible, and in vitro designs do not seem to be powerful tools to draw relevant conclusions, so in vivo and in situ designs become strongly recommended.

scholarly journals Osteogenesis Capability and Degradation Property Evaluation of Injectable Biomaterials: Comparison of Computed Tomography and Ultrasound

2013 ◽  
Vol 2013 ◽  
pp. 1-8
Author(s):  
Yan Chen ◽  
Yuting Yan ◽  
Xiaoming Li ◽  
He Li ◽  
Yue Yuan ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Quantitative Evaluation ◽  
Ultrasound Images ◽  
Noninvasive Technique ◽  
In Situ Forming ◽  
Property Evaluation ◽  
Analysis Technique ◽  
Defect Repair

Injectable biomaterials, which can be physically inserted into a target site without the use of surgery, have received increasing attention in tissue engineering during the last decade. There is also a growing need for quantitative evaluation of the injectable biomaterial directly and noninvasively. The objectives of this study are to originate a quantitative noninvasive technique for evaluation of in situ forming bone biomaterials and to validate the feasibility of diagnostic ultrasound images analysis technique. The potential of ultrasound for quantitative evaluation of tissue development was compared with computed tomography (CT)in vivo. A strong correlation was witnessed between ultrasound gray-scale values (GV) and volumetric mean of CT value (HUm) (r=0.95). Meanwhile, the volume of the material area could be estimated by ultrasound maximum cross-section pixel, which demonstrates a certain consistency with CT mask volume in 3D reconstruction images (r=0.87). In conclusion, ultrasound imaging, which is corresponding with the traditional CT, can be used to evaluate osteogenesis capability and degradation property of injectable biomaterials. It may be a noninvasive, nonradioactive, and effective aid to monitor ossification and reconstruction of biomaterials at the implant region for bone defect repair.

Sign in / Sign up

Export Citation Format

Share Document