Biomechanical Modeling of the Rectum for the Design of a Novel Artificial Anal Sphincter

2010 ◽  
Vol 44 (3) ◽  
pp. 257-260 ◽  
Author(s):  
Peng Zan ◽  
Guozheng Yan ◽  
Hua Liu ◽  
Banghua Yang ◽  
Yujuan Zhao ◽  
...  
Keyword(s):  
Anal Sphincter ◽  
Biomechanical Properties ◽  
Biomechanical Modeling ◽  
Sphincter Muscle ◽  
Artificial Anal Sphincter ◽  
Compression Function ◽  
Tissue Ischemia ◽  
Micro Pump ◽  
Human Rectum

Abstract This paper discusses biomechanical issues that are related to the option of a novel artificial anal sphincter around the human rectum. The prosthesis consists of a compression cuff system inside and a reservoir cuff system outside, which is placed around the debilitated sphincter muscle. The micro-pump shifts fluid between the cuffs and thus takes over the expansion and compression function of the sphincter muscle. However, the human rectum is not a rigid pipe, and motion in it is further complicated by the fact that the bowel is susceptible to damage. With the goal of engineering a safe and reliable machine, the biomechanical properties of the in-vivo porcine rectum are studied and the tissue ischemia is analyzed.

A Novel Artificial Anal Sphincter System in an in Vitro and in Vivo Experiment

2014 ◽  
Vol 37 (3) ◽  
pp. 253-263 ◽  
Author(s):  
Lei Ke ◽  
Guo-Zheng Yan ◽  
Hua Liu ◽  
Ping-Ping Jiang ◽  
Zhi-Qiang Liu ◽  
...  
Keyword(s):  
Anal Sphincter ◽  
Artificial Anal Sphincter ◽  
In Vivo Experiment

Inhibition of hyperplasia during the implantation of the puborectalis-like artificial anal sphincter

2020 ◽  
Vol 43 (7) ◽  
pp. 482-493
Author(s):  
Zerun Zhou ◽  
Guozhen Yan ◽  
Zhiwu Wang ◽  
Pingping Jiang ◽  
Shengjian Yao ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Anal Sphincter ◽  
Power Supply ◽  
Outer Shell ◽  
Power Supply Unit ◽  
Artificial Anal Sphincter ◽  
In Vivo Experiments ◽  
Nylon 12 ◽  
Transmission Structure

Objectives: This study aims to extend the implantation lifetime of the puborectalis-like artificial anal sphincter by inhibiting the occurrence of hyperplasia following the implantation process. Method: A new transmission structure was designed inside the puborectalis-like artificial anal sphincter to generate an adequate torque to maintain the feces, even if hyperplasia developed around the prosthetic sphincter. An outer shell was added to the prosthetic sphincter to decelerate the occurrence of hyperplasia on the outer shell side. Medical titanium alloy was tested to replace the nylon-12 prosthetic sphincter, while polyetheretherketone was used for the construction of the power supply unit in the puborectalis-like artificial anal sphincter system instead of nylon-12. In vivo experiments were conducted to evaluate all the methods presented in this study with 10 Pa Ma piglets, 1 domestic pig, and 1 beagle dog during the past 2 years. Results: Compared with the previous prosthetic sphincter that was equipped with a fixed-axle gear transmission, the new transmission structure is equipped with a planet-gear train managed to generate a prosthetic sphincter output with a 53% larger torque but with the same size and type of motor as that used previously and increase the implantation lifetime by 56%. After the replacement of the nylon-12, the new prosthetic sphincter made of medical titanium alloy succeeded in extending the implanted lifetime by 83%. In addition, the lifetime was increased by 143%, when an outer shell was added to the prosthetic sphincter. Polyetheretherketone significantly decreased the growth rate of hyperplasia around the power supply unit by 44% after the replacement of the power supply unit material. After the combination of all the improvements, the longest implantation lifetime of the puborectalis-like artificial anal sphincter during the in vivo experiments was 7 months and 10 days, which reflected an improvement of 249%. Conclusion: All methods posted in this study were evaluated to be effective to prolong the implantation lifetime of the puborectalis-like artificial anal sphincter. Among the methods proposed, the most effective was the addition of the outer shell to the puborectalis-like artificial anal sphincter. The least effective method was the improvement of the transmission structure. Medical titanium alloy and polyetheretherketone were good replacements for nylon-12 that managed to extend the implantation lifetime and yield a moderate improvement.

In Vitro and In Vivo Assessment of an Intelligent Artificial Anal Sphincter in Rabbits

2011 ◽  
Vol 35 (10) ◽  
pp. 964-969 ◽  
Author(s):  
Zong-Hai Huang ◽  
Fu-Jun Shi ◽  
Fei Chen ◽  
Fei-Xue Liang ◽  
Qiang Li ◽  
...  
Keyword(s):  
Anal Sphincter ◽  
Artificial Anal Sphincter ◽  
In Vivo Assessment

scholarly journals Biomechanics of Neutrophil Tethers

Life ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 515
Author(s):  
Andrea Cugno ◽  
Alex Marki ◽  
Klaus Ley
Keyword(s):  
Cell Activation ◽  
Optical Trap ◽  
Biomechanical Properties ◽  
Force Microscopy ◽  
Advantages And Disadvantages ◽  
Atomic Force ◽  
Microfluidic Flow ◽  
Biomembrane Force Probe ◽  
Membrane Reservoir

Leukocytes, including neutrophils, which are propelled by blood flow, can roll on inflamed endothelium using transient bonds between selectins and their ligands, and integrins and their ligands. When such receptor–ligand bonds last long enough, the leukocyte microvilli become extended and eventually form thin, 20 m long tethers. Tether formation can be observed in blood vessels in vivo and in microfluidic flow chambers. Tethers can also be extracted using micropipette aspiration, biomembrane force probe, optical trap, or atomic force microscopy approaches. Here, we review the biomechanical properties of leukocyte tethers as gleaned from such measurements and discuss the advantages and disadvantages of each approach. We also review and discuss viscoelastic models that describe the dependence of tether formation on time, force, rate of loading, and cell activation. We close by emphasizing the need to combine experimental observations with quantitative models and computer simulations to understand how tether formation is affected by membrane tension, membrane reservoir, and interactions of the membrane with the cytoskeleton.

scholarly journals Histological, Biomechanical, and Biological Properties of Genipin-Crosslinked Decellularized Peripheral Nerves

2021 ◽  
Vol 22 (2) ◽  
pp. 674
Author(s):  
Óscar Darío García-García ◽  
Marwa El Soury ◽  
David González-Quevedo ◽  
David Sánchez-Porras ◽  
Jesús Chato-Astrain ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Nerve Repair ◽  
Wistar Rat ◽  
Biomechanical Properties ◽  
Biological Properties ◽  
Suitable Alternative ◽  
Promising Alternative ◽  
Histological Pattern ◽  
The Impact

Acellular nerve allografts (ANGs) represent a promising alternative in nerve repair. Our aim is to improve the structural and biomechanical properties of biocompatible Sondell (SD) and Roosens (RS) based ANGs using genipin (GP) as a crosslinker agent ex vivo. The impact of two concentrations of GP (0.10% and 0.25%) on Wistar rat sciatic nerve-derived ANGs was assessed at the histological, biomechanical, and biocompatibility levels. Histology confirmed the differences between SD and RS procedures, but not remarkable changes were induced by GP, which helped to preserve the nerve histological pattern. Tensile test revealed that GP enhanced the biomechanical properties of SD and RS ANGs, being the crosslinked RS ANGs more comparable to the native nerves used as control. The evaluation of the ANGs biocompatibility conducted with adipose-derived mesenchymal stem cells cultured within the ANGs confirmed a high degree of biocompatibility in all ANGs, especially in RS and RS-GP 0.10% ANGs. Finally, this study demonstrates that the use of GP could be an efficient alternative to improve the biomechanical properties of ANGs with a slight impact on the biocompatibility and histological pattern. For these reasons, we hypothesize that our novel crosslinked ANGs could be a suitable alternative for future in vivo preclinical studies.

scholarly journals A composite scaffold of Wharton’s jelly and chondroitin sulphate loaded with human umbilical cord mesenchymal stem cells repairs articular cartilage defects in rat knee

2021 ◽  
Vol 32 (4) ◽  
Author(s):  
Zhong Li ◽  
Yikang Bi ◽  
Qi Wu ◽  
Chao Chen ◽  
Lu Zhou ◽  
...  
Keyword(s):  
Stem Cells ◽  
Articular Cartilage ◽  
Composite Scaffold ◽  
Biomechanical Properties ◽  
Cartilage Defects ◽  
Human Umbilical Cord ◽  
Composite Scaffolds ◽  
Articular Cartilage Defects

AbstractTo evaluate the performance of a composite scaffold of Wharton’s jelly (WJ) and chondroitin sulfate (CS) and the effect of the composite scaffold loaded with human umbilical cord mesenchymal stem cells (hUCMSCs) in repairing articular cartilage defects, two experiments were carried out. The in vitro experiments involved identification of the hUCMSCs, construction of the biomimetic composite scaffolds by the physical and chemical crosslinking of WJ and CS, and testing of the biomechanical properties of both the composite scaffold and the WJ scaffold. In the in vivo experiments, composite scaffolds loaded with hUCMSCs and WJ scaffolds loaded with hUCMSCs were applied to repair articular cartilage defects in the rat knee. Moreover, their repair effects were evaluated by the unaided eye, histological observations, and the immunogenicity of scaffolds and hUCMSCs. We found that in vitro, the Young’s modulus of the composite scaffold (WJ-CS) was higher than that of the WJ scaffold. In vivo, the composite scaffold loaded with hUCMSCs repaired rat cartilage defects better than did the WJ scaffold loaded with hUCMSCs. Both the scaffold and hUCMSCs showed low immunogenicity. These results demonstrate that the in vitro construction of a human-derived WJ-CS composite scaffold enhances the biomechanical properties of WJ and that the repair of knee cartilage defects in rats is better with the composite scaffold than with the single WJ scaffold if the scaffold is loaded with hUCMSCs.

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