China
Africa
Explore chapters and articles related to this topic
Mg-RE-Based Alloy Systems for Biomedical Applications
Published in Yufeng Zheng, Magnesium Alloys as Degradable Biomaterials, 2015
The Mg-2Y-1Zn alloy showed promising mechanical performance and microstructural stability in a previous study of Hanzi et al. (2010). In order to gain insight into the in vivo performance of the Mg-2Y-1Zn alloy, a preliminary animal study on Gottingen minipigs was performed. Sample disks of 4 mm diameter and 0.4 mm thickness were implanted into four different types of tissue in the abdomen (liver, lesser omentum) and in the abdominal wall (rectus abdominis muscle, subcutaneous tissue), respectively. All animals were in good general condition until sacrifice and showed no adverse reactions. Figure 11.18 shows the histopathological preparations derived from Mg-2Y-1Zn samples in various types of tissues, and it indicates homogeneous degradation and only limited gas formation during in vivo testing. The characteristics of the tissue reactions indicate good biocompatibility, and the Mg-2Y-1Zn alloy is believed to be promising for degradable implant applications.
Design of Abdominal Wall Hernioplasty Meshes Guided by Mechanobiology and the Wound Healing Response
Published in Jiro Nagatomi, Eno Essien Ebong, Mechanobiology Handbook, 2018
Shawn J. Peniston, Karen J.L. Burg, Shalaby W. Shalaby
Indirect inguinal hernias occur when a visceral sac leaves the abdominal cavity, enters the deep inguinal ring, and transcends the spermatic cord. The hernial sac contains peritoneum and viscera such as adipose tissue, intestinal loops, or omentum and is surrounded by all three fascial coverings of the spermatic cord. The hernia can traverse the entire inguinal canal and exit through the superficial inguinal ring. In severe cases the hernial sac enters the scrotum. Indirect inguinal hernias can occur in women, but they are twenty times more likely in males.
Gastrointestinal imaging 1: oesophagus, stomach and bowel
Published in Sarah McWilliams, Practical Radiological Anatomy, 2011
Fig. 4.4 (a) Diagram showing the stomach in an axial plain with the peritoneal reflections. The gastrosplenic ligament is shown, an important site for metastasis and the lesser omentum. The lesser omentum continues to join the liver as the gastrohepatic ligament. (b) Axial CT upper abdomen post-contrast showing the gastrohepatic ligament (1) and gastrosplenic ligament (2).
Comparison of small intestinal submucosa and polypropylene mesh for abdominal wall defect repair
Published in Journal of Biomaterials Science, Polymer Edition, 2018
Zhu-Le Wang, Shi-Zhou Wu, Zhi-Feng Li, Jin-Hai Guo, Yi Zhang, Jin-Kui Pi, Jun-Gen Hu, Xi-Jing Yang, Fu-Guo Huang, Hui-Qi Xie
Each dog was anesthetized with 0.04 mg/kg atropine and 15 mg/kg ketamine administered intramuscularly and 14–20 mg/kg thiopental sodium administered intravenously; anesthesia was maintained by inhalation of isoflurane and oxygen through an endotracheal tube. After successful anesthesia, the animal was fixed on the operating table in the supine position, with the abdominal hair removed. On the right side of the nipple, a skin incision of ~10 cm in length was made, followed by cutting the skin and subcutaneous tissue. The skin of the two sides was separated by blunt separation, revealing the muscular layer. The size of the defective area was measured and sintered at four vertices of the quasi-defective area with an electric knife as a surgical marker. Using the electric knife, we cut four mark points in the muscle (approximately 0.5 cm deep) of the abdominal cavity and raised the mark points to separate the omentum and abdominal wall. Subsequently, we cut the muscle tissue between the four incisions with an electric knife and completely cut a 4 cm × 6 cm section of the muscle with the peritoneum (Beagle model; Figure 1). We found that a 6 cm × 10 cm patch could be successfully used to repair the defect area without tension using 3-0 non-absorbable sutures (continuous hemstick suture); hence, this size was used for all SIS and SIS + PPM composite patches. In the case of the composite patches, the SIS was placed directly adjacent to the deep abdominal organs while the PPM was adjacent to the subcutaneous tissue at the shallow surface. After repair, the skin was sutured subcutaneously (3-0 non-absorbable suture; continuous subcutaneous tissue suture, and interrupted skin suture). All animals were fed in individual cages and administered cefazolin (500 mg, intravenously) once a day for 3 days postoperatively.
Fucoidan-based hydrogels particles as versatile carriers for diabetes treatment strategies
Published in Journal of Biomaterials Science, Polymer Edition, 2022
Lara L. Reys, Simone S. Silva, Diana Soares da Costa, Rui L. Reis, Tiago H. Silva
Despite being much less abundant than T2D, the higher morbidity, severity of the symptoms and drastic impact on patients’ quality of life associated with T1D pushed the development of new therapeutic strategies for this disease, as well as models to better understand it. In this perspective, insulin sustained delivery systems have been proposed as a therapeutic approach [10–15], as well as the development of devices for the encapsulation of insulin-producing pancreatic cells and islets of Langerhans, mainly based in hydrogels [16]. Different materials and processing methodologies are being explored, as carboxymethyl cellulose cryogels [17], hydrophilic polyurethanes processed as porous tough hydrogels [18], poly(ethylene glycol) hydrogel membrane functionalized with glucagon-like peptide [19], and more frequently alginate-based systems [20],including alginate-poly-l-lysine-alginate microcapsules[21], 3D printed porous alginate hydrogels [22], and even alginate coatings into nylon threads [23]. The resulting constructs are generally envisaged for further implantation near the patient liver [24, 25], but other implantation sites are also being studied, such as kidney capsule, spleen, intraperitoneal transplantation and omentum pouch, gastrointestinal wall intramuscular and subcutaneous site. In all the rational is the same, with the device being designed to support cell viability and reestablish the physiological secretion of insulin, while protecting the encapsulated cells from the host immune system [24, 26], although currently several bottlenecks are still to be surpassed [20, 27]. One of these is the foreign-body response that encapsulation materials may elicit, recognized for instance in alginate hydrogels, to which the combination with immunomodulating compounds may be the solution, as recently proposed with a chemically-modified alginate Z1-Y15 encapsulating viable pancreatic islets being implanted in a non-human primate model during 4 months without the need of immunosuppression drugs [28]. Other strategies also involve the use of bioactive compounds from marine resources as potential anti-diabetic drugs [29], such as fucoidan (Fu) a marine polysaccharide which has been reported as capable to regulate blood glucose homeostasis [30], besides several other biological activities, namely regarding antioxidant and immunomodulation effects [31]. Moreover, being a polysaccharide found in the cell wall of brown macroalgae, its role as a structural component for the development of biomaterials is being also addressed [32]. Thus, we hypothesized that Fu-based hydrogels may be attractive for the development of multifunctional carriers, as besides acting as support material for cells and drugs, may also enable the improvement of encapsulated cells viability by reducing oxidative stress [33] or modulate the immune response upon implantation. In this regard, the work reported herein aimed the establishment of Fu hydrogels without the use of additional polymers and evaluate their capacity to support drug loading and sustained release, as well as in vitro culture of pancreatic cells, as first assessment of carrier functionality.