Bone early phase

Hematopoiesis is defined as the development and maturation of blood cells and their precursors. In utero, hematopoiesis may occur in the liver, spleen, and bone marrow. However, after birth, it occurs exclusively in the bone marrow. All blood cells are generated from a common hematopoietic precursor, or stem cell. These stem cells are self-renewing and pluripotent and thus are able to commit to any one of the different lines of maturation that give rise to platelet-producing megakaryocytes, lymphoid, erythroid, and myeloid cells. The myeloid cell line produces monocytes, basophils, neutrophils, and eosinophils, whereas the lymphoid stem cell differentiates to form circulating B and T lymphocytes. In contrast to the ordered development of normal cells, the development of leukemia seems to represent an arrest in differentiation at an early phase in the continuum of stem cell to mature cell.1... 

Studies involving fluid shear, hydrostatic compression, biaxial and uniaxial stretch, or a combination of two or more of these factors indicate that fluid shear is a major factor affecting bone cell metabolism and cells subjected to mechanical stress reshape and align themselves with their long axis perpendicular to the axis of force. Cells also exhibited remodeling of the actin cytoskeleton and increases in PKC levels, processes thought to be involved in the early phase of mechanochemical transduction. 

Solid organ or bone marrow transplant recipients are a vulnerable group of patients prone to infectious and non-infectious metabolic encephalopathy (Todd, 2006). Depending on the time of the occurrence of the encephalopathy, several scenarios need to be considered. During the early phase of engraflment (usually the first 30 days) patients are vulnerable to infections with Candida, aspergillus, and the herpes... 

The most commonly employed model is the early uptake (EU) model, where U is deemed to have been taken up sufficiently shortly after burial for the bone to approximate to a closed system. Justification for the validity of early uptake seems to have stemmed from Szabo s (1979) suggestion, later elaborated on by Rae and Ivanovich (1986), that Uranium is fixed in the bone in the U oxidation state, facilitated by the reduction of U by decay products of the organic phase of bone, collagen. Since the bulk of collagen is lost rapidly from the bone (on the U-series time-scale at least), it is assumed Uranium will be taken up rapidly, and then uptake will cease. 

The presence of trace amounts of water in the organic phase is known to affect profoundly the rate of solid-liquid PTC processes. [11-13] Only recently has this problem been addressed by work in our laboratory as well as by Liotta and Sasson. Early in our polymerization studies we found that PTC polymerization did not occur in "bone dry" or "wet" solvents. Consequently, we undertook a... 

Among the apatite substituents, carbonate has been the subject of many studies. The apatite present in dental enamel is not a pure HA, but rather a corbonate apatite with a carbonate content of 2—3 %. There is still a controversy about the location of the carbonate in enamel, dentine and bone. While most recent studies agree that carbonate appears to be substituting within the lattice rather than existing in an amorphous phase, there is still some disagreement as to the actual position of the carbonate. The presence and location of the carbonate in dental enamel may relate directly to the risk of carious attack. Carbonate has been shown to be leaked preferentially from early carious lesions81. ... 

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