Bones remodelling

Pyridinium species comprise collagen cross-links that are formed during bone remodeling by osteoblasts. These cross-links are released into the serum and excreted in... 

Bone turnover Skeletal turnover Skeletal metabolism Bone remodelling... 

Bone remodelling, which continues throughout adult life, is necessary for the maintenance of normal bone structure and requires that bone formation and resorption should be balanced. Bone remodelling occurs in focal or discrete packets know as bone multicellular unit (BMU). In this process, both bone formation and resorption occur at the same place so that there is no change in the shape of the bone. After a certain amount of bone is removed as a result of osteoclastic resorption and the osteoclasts have moved away from the site, a reversal phase takes place in which a cement line is laid down. Osteoblasts then synthesize matrix, which becomes mineralised. The BMU remodeling sequence normally takes about 3 months to produce a bone structure unit (Fig. 2). 

Hormonal Regnlationof Calcinm Homeostasis and Bone Remodelling... 

PTH is the most important regulator of bone remodelling and calcium homeostasis. PTH is an 84-amino acid polypeptide and is secreted by the parathyroid glands in response to reductions in blood levels of ionised calcium. The primary physiological effect of PTH is to increase serum calcium. To this aim, PTH acts on the kidney to decrease urine calcium, increase mine phosphate, and increase the conversion of 25-OH-vitamin D to l,25-(OH)2-vitamin D. PTH acts on bone acutely to increase bone resorption and thus release skeletal calcium into the circulation. However, due to the coupling of bone resorption and bone formation, the longer-term effect of increased PTH secretion is to increase both bone resorption and bone formation. 

Bone Metabolism. Figure 2 The bone remodelling cycle. 

Bone Formation The building of new bone through osteoblasts. Bone formation, which is part of the bone remodelling process, includes the synthesis of organic matter (mostly collagen type 1) and subsequent mineralisation. 

Paget s disease is a chronic bone disorder characterized by abnormal bone remodeling. The disease disrupts the growth of new bone tissue causing the bone to thicken and become soft. This weakens the bone, which increases susceptibility of fracture even with slight trauma or collapse of the bone (eg, the vertebrae). 

WATKINS B A and SEIFERT M F (2001) Lipids as modulators of bone remodelling. Curr Opin Clin Nutr Metab Care 4, 105-10. 

Adhesion in vivo appears to be dynamic. Bonding to bone was observed to be disrupted as extensive bone remodelling took place, and then reestablished once damage had been repaired (Brook, Craig Lamb, 1991b). 

ELECTROCHEMICAL ASPECTS OE BONE REMODELING AND ERACTURE REPAIR 413... 

ELECTROCHEMICAL ASPECTS OF BONE REMODELING AND FRACTURE REPAIR... 

Guzelsu, N., and A. J. Salkind, Electrochemical aspects of bone remodeling, in Electrochemistry in Transition, J. Murphy, Ed., Plenum Press, New York, 1991. 

Under normal circumstances, the skeleton undergoes a dynamic process of bone remodeling. Bone tissue responds to stress and injury through continuous replacement and repair. This process is completed by the basic multicellular unit, which includes both osteoblasts and osteoclasts. Osteoclasts are involved with resorption or breakdown of bone and continuously create microscopic cavities in bone tissue. Osteoblasts are involved in bone formation and continuously mineralize new bone in the cavities created by osteoclasts. Until peak bone mass is achieved between the ages of 25 and 35, bone formation exceeds bone resorption for an overall increase in bone mass. Trabecular bone is more susceptible to bone remodeling in part owing to its larger surface area. 

Bone remodeling The constant process of bone turnover involving bone resorption followed by bone formation. 

The bone disease osteoporosis results when an imbalance occurs in the normal course of bone remodeling, a dynamic and highly regulated... 

The piezoelectric properties of collagen have been investigated in complex biological systems such as bone and tendon. The piezoelectric properties of bone have a great interest in view of their role in bone remodeling. The bone stress... 

Teriparatide is a recombinant product representing the first 34 amino acids in human parathyroid hormone. Teriparatide increases bone formation, the bone remodeling rate, and osteoblast number and activity. Both bone mass and architecture are improved. 

Diaz Curiel M, Calero JA, Guerrero R, Gala J, Gazapo R, de la Piedra C (1998) Effects of LY-117018 HC1 on bone remodeling and mineral density in the oophorectomized rat. Am J Obstet Gynecol 178 320-325... 

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