scholarly journals In Vivo Simulation of Magnesium Degradability Using a New Fluid Dynamic Bench Testing Approach

2019 ◽  
Vol 20 (19) ◽  
pp. 4859 ◽  
Author(s):  
Ole Jung ◽  
Dario Porchetta ◽  
Marie-Luise Schroeder ◽  
Martin Klein ◽  
Nils Wegner ◽  
...  
Keyword(s):  
Degradation Rate ◽  
Test Bench ◽  
Fluid Dynamic ◽  
Dynamic Test ◽  
Gas Production ◽  
Hydrogen Gas ◽  
Human Blood Plasma ◽  
Degradation Rates

The degradation rate of magnesium (Mg) alloys is a key parameter to develop Mg-based biomaterials and ensure in vivo-mechanical stability as well as to minimize hydrogen gas production, which otherwise can lead to adverse effects in clinical applications. However, in vitro and in vivo results of the same material often differ largely. In the present study, a dynamic test bench with several single bioreactor cells was constructed to measure the volume of hydrogen gas which evolves during magnesium degradation to indicate the degradation rate in vivo. Degradation medium comparable with human blood plasma was used to simulate body fluids. The media was pumped through the different bioreactor cells under a constant flow rate and 37 °C to simulate physiological conditions. A total of three different Mg groups were successively tested: Mg WE43, and two different WE43 plasma electrolytically oxidized (PEO) variants. The results were compared with other methods to detect magnesium degradation (pH, potentiodynamic polarization (PDP), cytocompatibility, SEM (scanning electron microscopy)). The non-ceramized specimens showed the highest degradation rates and vast standard deviations. In contrast, the two PEO samples demonstrated reduced degradation rates with diminished standard deviation. The pH values showed above-average constant levels between 7.4–7.7, likely due to the constant exchange of the fluids. SEM revealed severe cracks on the surface of WE43 after degradation, whereas the ceramized surfaces showed significantly decreased signs of corrosion. PDP results confirmed the improved corrosion resistance of both PEO samples. While WE43 showed slight toxicity in vitro, satisfactory cytocompatibility was achieved for the PEO test samples. In summary, the dynamic test bench constructed in this study enables reliable and simple measurement of Mg degradation to simulate the in vivo environment. Furthermore, PEO treatment of magnesium is a promising method to adjust magnesium degradation.

scholarly journals Mg-Zn-Ca Alloys for Hemostasis Clips for Vessel Ligation: In Vitro and In Vivo Studies of Their Degradation and Response

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3039 ◽  
Author(s):  
Yen-Hao Chang ◽  
Chun Chieh Tseng ◽  
Chih-Yeh Chao ◽  
Chung-Hwan Chen ◽  
Sung-Yen Lin ◽  
...  
Keyword(s):  
Degradation Rate ◽  
Protective Layer ◽  
Dip Coating ◽  
In Vivo Studies ◽  
Surface Measurement ◽  
In Vivo Experiments ◽  
Degradation Rates ◽  
And Behavior

To control the degradation rate of magnesium (Mg) alloys, chitosan (CHI) and L-glutamic acid (LGA) were used as coatings on Mg-Zn-Ca alloys via dip coating. In this study, either two or seven CHI/LGA layers were applied as a coating on Mg-2.8Zn-0.8Ca alloy (ZX31) and Mg-2.8Zn-0.8Ca hemostasis clips (ZX31 clips). The morphologies, compositions, and surface roughness of the specimens were characterized via scanning electron microscopy, Fourier transform infrared spectroscopy, and surface measurement devices. The degradation rates and behavior of the specimens were evaluated by immersing them in simulated body fluids and by applying these ZX31 clips on rabbits’ uterine tubes for five weeks. The specimen with seven layers (ZX31(CHI/LGA)7) exhibited improved corrosion behavior when compared with ZX31 or ZX31(CHI/LGA)2, with a reduced degradation rate of the Mg alloy in a simulated body environment. In vivo experiments showed that ZX31 clips exhibited good biocompatibilities in each group but could not maintain the clamping function for five weeks. The weight loss of ZX31(CHI/LGA)7 was significantly lower than that of the other groups. Consequently, it was verified that CHI can be used as a protective layer on a magnesium alloy surface via in vitro and in vivo experiments.

In vitro methods as predictors of voluntary intake and digestibility of hays fed to sheep

2002 ◽  
Vol 53 (4) ◽  
pp. 471 ◽  
Author(s):  
M. D. Carro ◽  
S. López ◽  
J. S. González ◽  
F. J. Ovejero ◽  
M. J. Ranilla
Keyword(s):  
Degradation Rate ◽  
Rumen Fluid ◽  
Predictive Ability ◽  
Gas Production ◽  
Regression Equation ◽  
Multiple Regression Equation ◽  
In Vitro Methods ◽  
First Order Kinetics

Eleven sun-cured hays were used to study the suitability of different in vitro methods to predict their voluntary dry matter (DM) intake (VDMI; g DM/kg liveweight) and in vivo DM digestibility (DMD; g/kg). The methods used were: (1) gas production at different incubation times when hays were incubated in vitro with buffered rumen fluid, (2) DM disappearance at different incubation times with cellulase (CEL), (3) release of sugars to the supernatant after incubation with cellulase, and (4) optical density of the supernatant at λ = 280 nm (as an indicator of phenolic compounds release) after incubation with cellulase. All kinetic data were fitted to first-order kinetics models to estimate the rate of degradation and the potential degradability, and the average degradation rate and effective degradability (ED) were calculated. The most accurate prediction of VDMI was by using the average degradation rate of the CEL method in a single regression equation, which accounted for 0.78 of the variation in intake (residual s.d. = 1.40). When only data from grass-rich hays were considered, the inclusion of potential degradability and rate of degradation of the CEL method in a multiple regression equation accounted for 0.98 of the variation in intake (residual s.d. = 0.32). The ED of the CEL method explained 0.93 and 0.92 of the variation in the in vivo DMD for all hays and grass-rich hays, respectively (residual s.d. = 18.1 and 21.7, respectively). The predictive ability of the different methods is discussed and compared with that of the in situ technique that has been previously reported.

scholarly journals Biocompatibility and Degradation Behavior of Molybdenum in an In Vivo Rat Model

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7776
Author(s):  
Antje Schauer ◽  
Christian Redlich ◽  
Jakob Scheibler ◽  
Georg Poehle ◽  
Peggy Barthel ◽  
...  
Keyword(s):  
Vessel Wall ◽  
Degradation Rate ◽  
Degradation Behavior ◽  
C Reactive Protein ◽  
In Vitro Degradation ◽  
Reactive Protein ◽  
Degradation Rates ◽  
In Vivo Degradation

The biocompatibility and degradation behavior of pure molybdenum (Mo) as a bioresorbable metallic material (BMM) for implant applications were investigated. In vitro degradation of a commercially available Mo wire (ø250 µm) was examined after immersion in modified Kokubo’s SBF for 28 days at 37 °C and pH 7.4. For assessment of in vivo degradation, the Mo wire was implanted into the abdominal aorta of female Wistar rats for 3, 6 and 12 months. Microstructure and corrosion behavior were analyzed by means of SEM/EDX analysis. After explantation, Mo levels in serum, urine, aortic vessel wall and organs were investigated via ICP-OES analysis. Furthermore, histological analyses of the liver, kidneys, spleen, brain and lungs were performed, as well as blood count and differentiation by FACS analysis. Levels of the C-reactive protein were measured in blood plasma of all the animals. In vitro and in vivo degradation behavior was very similar, with formation of uniform, non-passivating and dissolving product layers without occurrence of a localized corrosion attack. The in vitro degradation rate was 101.6 µg/(cm2·d) which corresponds to 33.6 µm/y after 28 days. The in vivo degradation rates of 12, 33 and 36 µg/(cm2·d) were observed after 3, 6 and 12 months for the samples properly implanted in the aortic vessel wall. This corresponds with a degradation rate of 13.5 µm/y for the 12-month cohort. However, the magnitude of degradation strongly depended on the implant site, with the wires incorporated into the vessel wall showing the most severe degradation. Degradation of the implanted Mo wire neither induced an increase in serum or urine Mo levels nor were elevated Mo levels found in the liver and kidneys compared with the respective controls. Only in the direct vicinity of the implant in the aortic vessel wall, a significant amount of Mo was found, which, however, was far below the amounts to be expected from degrading wires. No abnormalities were detected for all timepoints in histological and blood analyses compared to the control group. The C-reactive protein levels were similar between all the groups, indicating no inflammation processes. These findings suggest that dissolved Mo from a degrading implant is physiologically transported and excreted. Furthermore, radiographic and µCT analyses revealed excellent radiopacity of Mo in tissues. These findings and the unique combination with its extraordinary mechanical properties make Mo an interesting alternative for established BMMs.

scholarly journals Dose–Response Effects of 3-Nitrooxypropanol Combined with Low- and High-Concentrate Feed Proportions in the Dairy Cow Ration on Fermentation Parameters in a Rumen Simulation Technique

Animals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1784
Author(s):  
Matthias Schilde ◽  
Dirk von Soosten ◽  
Liane Hüther ◽  
Susanne Kersten ◽  
Ulrich Meyer ◽  
...  
Keyword(s):  
Dose Response ◽  
Gas Production ◽  
Hydrogen Gas ◽  
Simulation Technique ◽  
Mitigation Strategies ◽  
Feed Additive ◽  
Future Research ◽  
Dependent Manner ◽  
Dose Dependent

Methane (CH4) from ruminal feed degradation is a major pollutant from ruminant livestock, which calls for mitigation strategies. The purpose of the present 4 × 2 factorial arrangement was to investigate the dose–response relationships between four doses of the CH4 inhibitor 3-nitrooxypropanol (3-NOP) and potential synergistic effects with low (LC) or high (HC) concentrate feed proportions (CFP) on CH4 reduction as both mitigation approaches differ in their mode of action (direct 3-NOP vs. indirect CFP effects). Diet substrates and 3-NOP were incubated in a rumen simulation technique to measure the concentration and production of volatile fatty acids (VFA), fermentation gases as well as substrate disappearance. Negative side effects on fermentation regarding total VFA and gas production as well as nutrient degradability were observed for neither CFP nor 3-NOP. CH4 production decreased from 10% up to 97% in a dose-dependent manner with increasing 3-NOP inclusion rate (dose: p < 0.001) but irrespective of CFP (CFP × dose: p = 0.094). Hydrogen gas accumulated correspondingly with increased 3-NOP dose (dose: p < 0.001). In vitro pH (p = 0.019) and redox potential (p = 0.066) varied by CFP, whereas the latter fluctuated with 3-NOP dose (p = 0.01). Acetate and iso-butyrate (mol %) decreased with 3-NOP dose, whereas iso-valerate increased (dose: p < 0.001). Propionate and valerate varied inconsistently due to 3-NOP supplementation. The feed additive 3-NOP was proven to be a dose-dependent yet effective CH4 inhibitor under conditions in vitro. The observed lack of additivity of increased CFP on the CH4 inhibition potential of 3-NOP needs to be verified in future research testing further diet types both in vitro and in vivo.

In Vitro Degradation of β-TCP/PLLA Scaffolds with Different Proportions of β-TCP

2007 ◽  
Vol 336-338 ◽  
pp. 1545-1548
Author(s):  
Lin Luo ◽  
Guang Fu Yin ◽  
Yun Zhang ◽  
Ya Dong Yao ◽  
Wei Zhong Yang ◽  
...  
Keyword(s):  
Degradation Rate ◽  
Porous Scaffolds ◽  
Carbonate Apatite ◽  
Tissue Formation ◽  
Cellular Attachment ◽  
Biodegradable Scaffolds ◽  
Scaffold Structure ◽  
Mechanical Strengths

Porous biodegradable scaffolds are widely used in bone tissue engineering to provide temporary templates for cellular attachment and matrix synthesis. Ideally, the degradation rate in vivo may be similar or slightly less than that of tissue formation, allowing for the maintenance of the scaffold structure and the mechanical support during early stages of tissue formation. Eventually, the 3-D spaces occupied by the porous scaffolds will be replaced by newly formed tissue. In this work, β-tricalcium phosphate/Poly-L lactide (β-TCP/PLLA) scaffolds with different proportions of β-TCP to PLLA were investigated. The effects of β-TCP proportions on degradation rate and mechanical strengths of the scaffolds were evaluated in simulated body fluid (SBF) at 37°C up to 42 days. Results show that: different proportions of β-TCP to PLLA have significant influence on degradation behaviors of the scaffolds, and mechanical strengths of the scaffolds with weight proportion of β-TCP to PLLA being 2 to 1 are much higher than those of the others during the degradation period. And in this period, the scaffolds biodegrade slowly, and Hydroxyl Carbonate Apatite (HCA) forms in the surface of the material.

In Vitro and In Vivo Degradation, Mechanical Properties, and Histocompatibility of Weft-Knitted Silk Mesh-Like Grafts

2022 ◽  
Vol 12 (2) ◽  
pp. 411-416
Author(s):  
Liang Tang ◽  
Si-Yu Zhao ◽  
Ya-Dong Yang ◽  
Geng Yang ◽  
Wen-Yuan Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Simulated Body Fluid ◽  
Body Fluid ◽  
Degradation Rate ◽  
Maximum Load ◽  
Artificial Ligament ◽  
In Vivo Degradation

To investigate the degradation, mechanical properties, and histocompatibility of weft-knitted silk mesh-like grafts, we carried out the In Vitro and In Vivo silk grafts degradation assay. The In Vitro degradation experiment was performed by immersing the silk grafts in simulated body fluid for 1 year, and the results showed that the degradation rate of the silk mesh-like grafts was very slow, and there were few changes in the mechanical properties and quality of the silk mesh-like graft. In Vivo degradation assay was taken by implantation of the silk mesh-like grafts into the subcutaneous muscles of rabbits. At 3, 6, and 12 months postoperation, the rate of mass loss was 19.36%, 31.84%, and 58.77%, respectively, and the maximum load was 63.85%, 34.63%, and 10.76%, respectively of that prior to degradation. The results showed that the degradation rate of the silk graft and the loss of mechanical properties In Vivo were faster than the results obtained in the In Vitro experiments. In addition, there were no significant differences in secretion of serum IL-6 and TNF-α between the experimental and normal rabbits (P >0.05), suggesting no obvious inflammatory reaction. The findings suggest that the weft-knitted silk mesh-like grafts have good mechanical properties, histocompatibility, and In Vivo degradation rate, and therefore represent a candidate material for artificial ligament

Degradation Behaviour of Metallic Biomaterials for Degradable Stents

2006 ◽  
Vol 15-17 ◽  
pp. 113-118 ◽  
Author(s):  
Hendra Hermawan ◽  
Maryam Moravej ◽  
Dominique Dubé ◽  
Michel Fiset ◽  
D. Mantovani
Keyword(s):  
Potentiodynamic Polarization ◽  
Degradation Rate ◽  
Corrosion Behaviour ◽  
Dynamic Test ◽  
Potential Candidate ◽  
Human Coronary Artery ◽  
Ion Release ◽  
Degradation Behaviour ◽  
Static Immersion

The short-term need of scaffolding function of stent and the prevention of potential longterm complication of permanently implanted stent have directed to the original idea of biodegradable stent. Selecting and developing materials showing appropriate mechanical and degradation properties are key steps for the development of this new class of medical devices. Therefore, the study of their in vitro degradation behaviour is mandatory for the selection of potential candidate materials suited in vivo. In this work, the degradation behaviour of current studied biodegradable metals including three magnesium alloys (Mg, AM60B and AZ91D), pure iron and Fe-35Mn was investigated. The tests were performed in a simulated blood plasma solution at 37±0.1 oC, using three different methods; potentiodynamic polarization, static immersion, and dynamic test in a test-bench which mimics the flow condition in human coronary artery. Degradation rate was determined as ion release rate measured by using atomic adsorption spectroscopy (AAS) and also estimated from weight loss and corrosion current. Surface morphology and chemical composition of corroded specimens were analyzed by using SEM/EDS. The three degradation methods provide consistent results in corrosion tendency, where Mg showed the highest corrosion rate followed by AZ91D, AM60B, Fe-35Mn and iron. Potentiodynamic polarization gives a rapid estimation of corrosion behaviour and rate. Static immersion test shows the effect of time on the degradation rate and behaviour. Dynamic test provides the closest approach to the environment after stent implantation and its results show the effect of the flow on the materials degradation. In conclusion, the three investigated methods can be applied for screening, selecting and validating materials for degradable stent application before going further to in vivo assessments.

scholarly journals In vitro and in vivo assessment of biomedical Mg–Ca alloys for bone implant applications

2018 ◽  
Vol 16 (3) ◽  
pp. 126-136 ◽  
Author(s):  
Preeti Makkar ◽  
Swapan Kumar Sarkar ◽  
Andrew R. Padalhin ◽  
Byoung-Gi Moon ◽  
Young Seon Lee ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Bone Formation ◽  
Femoral Condyle ◽  
Immersion Test ◽  
Hydrogen Gas ◽  
In Vivo Studies ◽  
Biodegradable Implant ◽  
In Vitro Degradation

Background: Magnesium (Mg)-based alloys are considered to be promising materials for implant application due to their excellent biocompatibility, biodegradability, and mechanical properties close to bone. However, low corrosion resistance and fast degradation are limiting their application. Mg–Ca alloys have huge potential owing to a similar density to bone, good corrosion resistance, and as Mg is essential for Ca incorporation into bone. The objective of the present work is to determine the in vitro degradation and in vivo performance of binary Mg– xCa alloy ( x = 0.5 or 5.0 wt%) to assess its usability for degradable implant applications. Methods: Microstructural evolutions for Mg– xCa alloys were characterized by optical, SEM, EDX, and XRD. In vitro degradation tests were conducted via immersion test in phosphate buffer saline solution. In vivo performance in terms of interface, biocompatibility, and biodegradability of Mg– xCa alloys was examined by implanting samples into rabbit femoral condyle for 2 and 4 weeks. Results: Microstructural results showed the enhancement in intermetallic Mg2Ca phase with increase in Ca content. Immersion tests revealed that the dissolution rate varies linearly, with Ca content exhibiting more hydrogen gas evolution, increased pH, and higher degradation for Mg–5.0Ca alloy. In vivo studies showed good biocompatibility with enhanced bone formation for Mg–0.5Ca after 4 weeks of implantation compared with Mg–5.0Ca alloy. Higher initial corrosion rate with prolonged inflammation and rapid degradation was noticed in Mg–5.0Ca compared with Mg–0.5Ca alloy. Conclusions: The results suggest that Mg–0.5Ca alloy could be used as a temporary biodegradable implant material for clinical applications owing to its controlled in vivo degradation, reduced inflammation, and high bone-formation capability.

scholarly journals Nutritional diversity of Brachiaria ruziziensis clones

2018 ◽  
Vol 48 (2) ◽  
Author(s):  
Ellen de Almeida Moreira ◽  
Shirley Motta de Souza ◽  
Alexandre Lima Ferreira ◽  
Thierry Ribeiro Tomich ◽  
José Augusto Gomes Azevêdo ◽  
...  
Keyword(s):  
Degradation Rate ◽  
Neutral Detergent Fiber ◽  
Ruminal Fermentation ◽  
Dry Matter Digestibility ◽  
Brachiaria Ruziziensis ◽  
Hierarchical Grouping ◽  
Degradation Rates ◽  
Main Components ◽  
Lower Contribution

ABSTRACT: The aim of this study was to evaluate the nutritional diversity of Brachiaria ruziziensis clones through chemical composition and in vitro kinetics of ruminal fermentation. Twenty three clones of Brachiaria ruziziensis were used (15, 16, 46, 174, 411, 590, 651, 670, 768, 776, 844, 859, 950, 965, 970, 975, 1067, 1093, 1296, 1765, 1806, 1894 and 1972) and Brachiaria ruziziensis cv. ‘Kennedy’, Brachiaria brizantha cv. ‘Marandu’ and Brachiaria decumbens cv. ‘Basilisk’ as controls within 27 days of harvesting. The experimental design used randomized blocks with 26 treatments (genotypes) and three replications. Evaluation of the nutritional divergence was performed using principal components analysis, based on the following discriminatory variables: in vitro dry matter digestibility (IVDMD), neutral detergent fiber (NDF), lignin, crude protein (CP), degradation rate of non-fibrous carbohydrates (KdNFC) and degradation rate of fibrous carbohydrates (KdFC). The evaluation of the nutritional diversity of Brachiaria genotypes was based on the two main components (IVDMD and NDF), which explains 96.2% of the total variance Variables of lower contribution to the discrimination of the clones were as degradation rates of the fibrous and non-fibrous carbohydrates. In the agglomerative hierarchical grouping analysis, five distinct groups were identified, where V group, formed by clones 46, 768 and 1067 have higher values of IVDMD compared to the other clones.

Effect of non-digestible oligosaccharides in diets for weaner pigs on in vitro fermentation

1998 ◽  
Vol 1998 ◽  
pp. 30-30 ◽  
Author(s):  
J.G.M. Houdijk ◽  
B.A. Williams ◽  
S. Tamminga ◽  
M.W.A. Verstegen
Keyword(s):  
Gas Production ◽  
Production Technique ◽  
In Vitro Fermentation ◽  
Weaner Pigs

Dietary fructooligosaccharides (FOS) shifted the proportion of propionate (↑) and acetate (↓) compared to transgalactooligosaccharides (TOS) in weaner pigs' ileal digesta, both in vivo and in vitro (Houdijk et al., 1997). This could be related to different fermentation rates between these so-called non-digestible oligosaccharides (NDOs). These rates were studied via the cumulative gas production technique comparing FOS, TOS, and glucose.

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