Bone loss properties

Selective estrogen receptor modulators (SERMs) are synthetic compounds with partially agonistic and partially antagonistic estrogenic properties. In bone, SERMs inhibit bone resorption via the mechanisms known for estrogens. Major SERMs are tamoxifen, a triphenylethylene compound, and raloxifene. In postmenopausal women, the latter has been shown to prevent bone loss and to reduce fracture risk by 40%. 

Ovariectomized (ovx) cynomolgus monkeys represent a common model for postmenopausal osteoporosis because they experience regular menstrual cycles, hormonal fluctuations and bone loss upon ovariectomy. Both, ovx monkeys and postmenopausal osteoporotic women showed similar modifications in trabecular mineral properties [65], specifically a decreased mineral matrix ratio, increased crystallinity and increased carbonate content relative to controls. In addition, the spatial variation in the mineral matrix ratio was the same in humans and monkeys. 

Since PMMA has mechanical properties that are similar to bone, its use in joint replacement devices may allow a more physiologic transfer of loads from the prosthesis to the remaining bone, which may in turn reduce stress-shielding and the resulting bone loss. PMMA stabilizes implants within the surrounding bone, reducing unwanted micromotions and can act as a load damper [5]. 

Hydroxyapatite [Caio(P04)6(OH)2] (HA) is one of the most stable forms of calcium phosphate (Kim and Mendis, 2006) and is used in variety of areas, including orthopedic, dental and maxillofacial applications. HA has recently emerged as an important compound for artificial bone preparation due to its osteoconductive properties. The structural similarity of HA with the bone has proven that it can mimic the natural function of bone due to its biocompatibility and osteoconductive nature. However, the mechanical strength of HA is a serious concern when it is used to replace or treat bone loss or defects (Zhou and Lee, 2011). Composite scaffold of... 

As the therapy of AMD is very limited, there is an urgent need to develop an intervention to prevent vision loss. The epidemiological data together with the well-documented antioxidant properties of carotenoids in studies in vitro and with proven increases in macular pigment density in most people via dietary supplementation (Beatty et al., 2004 Berendschot et al., 2000 Bone et al., 2003 Hammond et al., 1997 Iannaccone et al., 2007 Landrum et al., 1997), including patients with early AMD (Koh et al., 2004 Obana et al., 2008 Richer et al., 2007 Trieschmann... 

Moreover hemopoietic stem cells-precursors derived from cord blood have higher potential of proliferation and expansion than their analogues from adult bone marrow. Extended cord blood use as a source of hemopoietic cells resulted in the necessity to establish cord blood banks where the samples could be stored in a frozen state at -196 C for a long time with no loss of their biological properties. 

Vitamin C is essential for the formation of collagen, the principal structural protein in skin, bone, tendons, and ligaments, being a cofactor in the hydroxylation of the amino acids proline to 4-hydroxyproline, and of lysine to 5-hydroxylysine. These hydroxyamino acids account for up to 25% of the collagen structure. Vitamin C is also associated with some other hydroxylation reactions, e.g. the hydroxylation of tyrosine to dopa (dihydroxyphenylalanine) in the pathway to catecholamines (see Box 15.3). Deficiency leads to scurvy, a condition characterized by muscular pain, skin lesions, fragile blood vessels, bleeding gums, and tooth loss. Vitamin C also has valuable antioxidant properties (see Box 9.2), and these are exploited commercially in the food industries. 

Lead is an acute and a chronic toxicant. Acute effects are ataxia, headache, vomiting, stupor, hallucination, tremors and convulsions. Chronic symptoms from occupational exposure include weight loss, anemia, kidney damage and memory loss. (Patnaik, P. 1999. A Comprehensive Guide to the Hazardous Properties of Chemical Substarwes, 2nbrain damage has been noted among children. Lead bioaccumulates in bones and teeth. The metal is classified as an environmental priority pollutant by the US EPA. 

Bone marrow toxicity is the major side effect of chlorambucil. Nausea is uncommon or mUd, and hair loss does not occur. Chlorambucil shares the immunosuppressive, teratogenic, and carcinogenic properties of the nitrogen mustards. 

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