Lamellar bone

Fluorid ions stimulate bone formation by a direct mitogenic effect on osteoblasts mediated via protein kinase activation and other pathways. Further to these cellular effects, fluorides alter hydroxyapatite crystals in the bone matrix. In low doses, fluorides induce lamellar bone, while at higher doses abnormal woven bone with inferior quality is formed. The effect of fluorides on normal and abnormal (e.g. osteoporotic) bone therefore depends on the dose administered. 

Figure 2. Diagram of two osteocytes (1) in the lamellar bone of calcified bone matrix (3). Two neighboring lamellae (2) with different collagen fiber orientations (7) are visible. The osteocytic cell bodies are located in lacunae and are surrounded by a thin layer of uncalcified matrix (4). Their cell processes (5) are housed in canaliculi (6). Some of the gap junctions between the cell processes are indicated (arrows). Modified from Krstic (1978).

Sauren, Y.M.H.F., Mieremet, R.H.P., Groot, C.G. and Scherft, J.P. (1992) An electron microscopic study on the presence of proteoglycans on the mineralized matrix of rat and human compact lamellar bone. The Anatomical Record 232 36-44... 

The other microarchitectural form of bone, lamellar bone, actively replaces maturing woven bone and, consequently, contains up to 100 times more mineralized matrix or hydroxyapatite these hydroxyapatite crystals... 

Cortical bone, also called compact or lamellar bone, is remodelled from woven bone by means of vascular channels that invade the embryonic bone from its periosteal and endosteal surfaces. It forms the internal and external tables of flat bones and the external surfaces of long bones. The primary structural unit is an osteon, also known as a Haversian system, a cylindrical shaped lamellar bone surrounding longitudinally oriented vascular channels (the Haversian canals). Horizontally oriented canals (Volkmann canals) connect adjacent osteons. The mechanical strength of cortical bone results from the tight packing of the osteons. 

Figure 3 Structures of mammal bone (a) Haversian systems and osteons, (b) Pl)rwood-like structure with twisted lamella, (c) Lamellar bone showing the different orientations of fibers in successive lamella, (d) Minerahzed collagen fibers...

Figure 23 Mammalian bone at different levels of resolution (a) Collagen fibril with associated mineral, (b) Woven bone (random collagen distribution), (c) Lamellar bone showing separate lamellae with collagen organized in domains with preferred orientation alternating in adjacent lamellae, (d) Woven bone with blood channels shown as dark spots, woven bone stippled, (e) Primary lamellar bone orientation indicated by dashes, (f) Haversian bone, a collection of haversian systems are shown as a longitudinal structure. Each system has concentric lamellae around a central blood channel. Darkened area represents an empty (eroded) portion of the section which will be reconstituted with new bone, (g) Alternation of woven and lamellar bone, (h) Various orientations of heavily mineralized (cortical, or compact) bone, (i) Trabecular, or cancellous, bone (Wainwright et aL, 1976) (reproduced by permission of Hodder Arnold from Mechanical Design in Organisms, 1976).

Fig shows the histolq ical observation after 1(a), 4(b), 8 eeks(c) by optical miaoscopy. The area dose to FGM implant in Fig.2 is enlarged to M r uriagnifiearinti. In 1 week new bone is immature and mtiher difficult to recognize. After 4 weeks the newly formed waven Ixme is dearly observed dose to the implant but not yet in direct contact After 8 weeks the implant is folly surrounded and directly contact with the new bone. The new bone is enou mature and scxne parts were remodeled to the lamellar bone. Bone marrow is also seen with vdiite contrast... 

Patients with this disorder, which is probably inherited as an autosomal recessive trait, suffer from marked skeletal deformities due to rapid turnover of lamellar bone with failure to lay down compact cortical bone (E19, T4). Abnormal amino acids are excreted in the urine and serum alkaline phosphatase, which is indistinguishable from that circulating in patients with other skeletal disorders (E19), is spectacularly elevated. 

Ossifying fibromyxoid tumor (OFMT) of soft parts is a slowly growing mesenchymal lesion with a propensity to arise on the extremities, in the deep subcutis or skeletal muscles. Microscopically, this neoplasm is composed of lobulated nests of compact, cytologically bland round cells in a variably myxoid or densely hyalinized stroma. An incomplete shell of lamellar bone is a usual feature, but it may be absent in selected instances. The tumor cells of OFMT stain strongly and diffusely for S-100 protein and vimentin in most cases.Occasional reactivity may also be seen for keratin, CD57, synapto-... 

Weiner, S., W. Traub, and H. D. Wagner. 1999. Lamellar bone structure-function relations. J. Struc. Biol. 126 241-255. 

Reznikov, N., Shahar, R., and Weiner, S. (2014a) Three-dimensional structure of human lamellar bone the presence of two different materials and new insight into the hierarchical organization. Bone, 59, 93-104. 

Weiner, S., Traub, W., and Wagner, H. (1999) Lamellar bone structure-function relation. /. Struct. Biol., 126, 241-255. 

Plexiform Also called laminar. The form of parallel lamellar bone found in younger, immature nonhuman mammals. 

PTFE barriers were completely repaired with bone tissue, whereas incomplete lamellar bone formation was detected in defects treated with Gengiflex membranes, resulting in voids and lack of continuity of bone deposition. This demonstrated that the non-porous PTFE barrier is a more effective alternative to treat osseous defects than a bacterial cellulose membrane. 

Lamellar bone Parallel fibrils and/or fiber bundles are arranged in layers, with the fihril orientation in each layer being different. 

Certain combinations of fibril array organizations result in specific stmctures, like the formation of lamellar bone into secondary osteons, as described in Section 9.03.3.5.2. 

Akiva, U., Wagner, H. D., and Weiner, S. (1998), Modelling the three-dimensional elastic constants of parallel-fibred and lamellar bone, J. Mater. Sci. 33(6) 1497-1509. 

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