It is clear that the use of bone grafts has obviously grown in the last years for periodontal and maxillofacial applications. Although autogenous graft is the gold standard due to its neglected risk of disease transmission and developing a harmful immune response following its implantation, a variety of complication like pain or arterial injury, as well as, donor site morbidity are likely to be provoked(1). Therefore, allograft is considered an appropriate modality. However, they can initiate unwanted immune response (2, 3). The ideal osteoinductive and osteoconductive properties are obtained with fresh allograft. However, they trigger severe immune response (4, 5). Trials have been done to reduce such immunogenicity. Studies have revealed …show more content…
The macrophages first identify allo-antigens, and then they engulf these antigens to be finally presented via MHC molecule. Following this step, macrophages secrete (IL-1, IL-6 and TNF-α) in order to activate T cells and to attract more macrophages (33-36). The activated lymphocytes release a variety of cytokines either to stimulate the differentiation and proliferation of osteoclasts either directly or indirectly like IL-7 (37), IL-15 (38), IL-17 by Th17 (39-41) and INF-γ (42), or suppress osteoclastogenesis as IL-4 (43), and IL-13 (38). T cells are classified into two major types CD8 and CD4. CD4 cells include Th1, Th2, Th17, and Treg cells. The latter have the ability to suppress immune reactions, and consequently graft rejection …show more content…
Moreover, different cytokines play a crucial role in controlling bone remodeling. It has been revealed that the main regulatory cytokines are RANKL, RANK, OPG, M-CSF, IGF-I, IGF-II, TGF-β, interleukin1 (IL-1), IL-6, tumor necrosis factor a (TNF-α) (52).Generally, there is a group of cytokines that is responsible for regulation of osteoblasts including IL-1, 3, 7, 10, 13,TNF-α and interferon-γ. While IL-1, 3, 4, 6–8, 10–13, 15, 17, 18, 23, TNF-α, OPG, leukocyte inhibition factor (LIF), M-CSF, and interferon-g are involved in the regulation of osteoclasts
However some of the basic bone functions include storing of crucial nutrients, minerals and lipids, producing red blood cells for the body, protect the organs such as heart, ribs and the brain, aide in movement and also to act as a buffer for pH. With the differences in all of the bones there are four things that remain the same in each bone, their cells. Bones are made up of four different cells; osteoblasts, osteoclasts, osteocytes and bone lining cells. Osteoblasts produce and secrete matrix proteins and then transport the minerals into the matrix. Osteoclasts are responsible for the breaking down of tissue. The osteoblasts and osteoclasts are both responsible for remodeling and rebuilding of bones as we grow and age. The production of osteoclasts for resorption is initiated by the hormone, the parathyroid hormone. Osteocytes are the mature versions of osteoblasts because they are trapped in the bone matrix they produced. The osteocytes that are trapped continue making bone to help with strength and the health of the bone matrix. The bone lining cells are found in the inactive bone surfaces which are typically found in
An osteoblast is a “baby” bone cell whose main job is to secrete osteoid which forms the hardened, or calcified, bone matrix. Osteocytes are formed from osteoblasts. Osteocytes are the mature bones cells that have been completely differentiated. They are found in the lacunae of hard bone and have a spider-like appearance due to their canaliculi. Osteoclasts are a different type of cell formed from the mesenchymal cells. These cells are not related to osteoblasts or osteocytes. Their job is to basically “eat” the bone to create cavities and other hallow spaces during bone remodeling. Finally, the cells form differentiate to form fibroblasts and fibrocytes. These fibroblasts and fibrocytes secrete and form the matrix for fibrous connective tissue which is an essential component of the
The etiology of calcaneal fracture is usually high energy trauma such as fall from a height or motor vehicle crash 1,2.
In orthopedic surgery, iliac bone graft which is commonly used for treatment nonunion or spinal fusion is contained multipotential stem cells or mesenchymal progenitor cells. These cells are found approximately 1 in 10,000 nucleated cells in the bone marrow. Friedenstein et al. (1970) reported that a rare population of cells was found by plastic-adherent ability (Friedenstein et al., 1970). These cells are capable of proliferation and mesenchymal lineages differentiation (Pittenger et al., 1999, Caplan, 1991). Unique antigens of MSCs (hMSCs) are controversy and the limited popularity of sorting cells techniques are not as widely used as gradient media in MSC isolation. Most MSC populations have been isolated by plastic adherent ability which is similar to that originally used by Friedenstein. Direct BM plating method is commonly used for cells from small animal (Lennon and Caplan, 2006, Nadri et al., 2007) but in human bone marrow, Density gradient centrifugation is the most commonly used method for isolating MSCs.
The major practical issue to be surmounted with any transplant is immunological. For a transplant to be successful the transplanted tissue must not...
The skeletal system consists of 206 bones and has other body attachments that assist in connecting them which are tendons, ligaments, and cartilage. The skeletal system provides vital functions for the human body. The functions this system provides are support, movement, protection, blood cell production, storage for calcium and endocrine regulation. Bone serves as the basic unit of the human skeletal system. Ossification is characterized as a process that produces new bone. This process is also known as bone formation. Bone formation consists of two types of development. They are intramembranous and endochondral formation. Intramembranous ossification takes place when cells within the membrane change and become osteochondral progenitor cells.
The decision to have breast reconstruction is a personal one. Getting as much information as possible is the first step in making this decision. Knowing how this procedure is done is part of that investigative process.
A femoral head preserving operation having satisfactory results in long term follow up should be the treatment of choice in younger individuals and THR in elderly where femoral head is badly damaged and in younger patients with multisystem diseases and poor general health. Considering the life style of people of our country who needs squatting habit, decompression of femoral head and TFL muscle pedicle bone grafting is a good option both in early and even in advanced stages of the disease unless the femoral head is badly deformed or collapsed more than 5mm. Considering its technical simplicity compared to the use of other vascularised bone grafts like vascularised fibular or vascular pedicle iliac crest graft, the above method can be recommended in patients of developing countries like ours where osteonecrosis is common.
Osteoporosis is a serious disease that leads to a faster than normal loss of the bone density, which puts the bone at a higher risk for fractures. In order to understand the causes of Osteoporosis, it is important to understand how bones are formed. Bone is a living tissue that is made mainly of collagen, calcium phosphate, and calcium carbonate. The mixture of collagen and calcium gives the bone strength and flexibility. The body deposits new bones and removes old ones; moreover, there are two types of bone cells that control the reproduction of bones. Cells called osteoclasts breakdown bone tissues thus, damaging the bone. Once the damaged bone is removed, cells called osteoblasts, use minerals including calcium and phosphate from the blood stream to make new healthy bone tissues. In order for osteoblasts and osteoclasts to work properly, hormones such us thyroid, estrogen, testosterone, and growth hormones are
Osteoporosis is a systemic, debilitating disease of the skeleton, characterized by significantly decreased bone mass in combination with the deterioration of bone microarchitecture. Osteoporosis has three types of categories the first category is type 1 which occurs in women after menopause and results from declining levels of estrogen and other sex hormones in the body, this could also occur in men due to low levels of the sex hormone testosterone. Type 2 is called Senile Osteoporosis, which occurs in elderly men as well as elderly women because of decreased bone formation due to aging. Type 3 is caused by long term use of medication usually with steroids and drugs to treat elipsy. Osteoporosis which literally means “Porous Bone”,
An allograft is either bone, cartilage, tissue, ligament, tendon or any section of the skin that is donated from another person that is deceased. Allografts do contain osteoconductive scaffolds with minimal osteoinductive factors. A disadvantage of Allografts is the risk of bacterial contamination or the possibility of viral transmission diseases such as hepatitis and human immunodeficiency5. Jorgenson et al.6 Conducted a prospective analysis in lumbar fusion of allografts versus autografts in the same patient and concluded that an ethylene oxide-treated allograft is inferior to an autograft and should not be used for posterior lumbar fusions(Level II). Further, An et al.7conducted a prospective comparison of autografts and allografts for adult posterolateral lumbar spinal fusion and reported that autografts resulted in significantly greater bone density, followed by the mixture of autografts and allografts, frozen allografts, and freeze-dried allografts (Level II). These reports indicate that allografts alone were not able to achieve a sufficient fusion rate for posterior spinal fusion in the adult
The human body endures a great deal of wear and injury during its lifetime. It is for this reason that the body has several tissues that are capable of regeneration. Bone is one of those tissues that receives extensive use so it is necessary that it is strong in order to carry out its functions; however, it will occasionally face injury. Although our bones are capable of regeneration, a new method would help the elderly and others that have a more difficult time healing after injury. I viewed a “TED Talk” lecture, which discussed a new way of regenerating bone with the help of our own bodies. Molly Stevens, the head of a biomaterials lab, presented “A New Way to Grow Bone” where she discussed a new technique called “in vivo bioreactor”. She also answered why this new procedure is beneficial. Researchers like Stevens are constantly trying to find innovative new techniques and they do this by asking questions. The question that Stevens presented in the video was an intriguing one: “Can we recreate the regeneration of bone on demand and transplant it?”.
The skeletal system is composed of two hundred and six bones in the human body. Functions such as the tendons, cartilage, and ligaments connect the bones and tissues together. Bone tissues make up about 18% of the weight of the human body. There are two types of tissue inside the bones. They consist of; compact bone and spongy bone. First, compact bone depicts the main shaft of long bones in the human body such as the arms and legs. Its tissue is dense and hard and it also makes up the outer layer of most bones in our body. Meanwhile, spongy bone tissue is made up of smaller plates occupied with red bone marrow. Mostly, it is found at the ends of long bones such as the head of the femur.
Bone cancer is classified into primary bone cancer & secondary bone cancer. Basically, Primary bone cancer starts in the bone; then the cancer initially forms in the cells of the bone; while the secondary cancer starts elsewhere in the body and gets spread to the bone.
The Skeletal System, also known as the Skeleton make up a framework that support the body and protect the organs. The Skeleton consists of the bones and joints of the body. In the human body there is 300 bones at birth, these then fuse together to make 206 bones in a fully grown adult. The Skeleton is made up of two divisions: The axial and appendicular Skeleton.