Calcium in the bone

Since this increased calcium loss, the quality of dietary protein may be important in conserving body calcium in the bone reservoir via the kidney. Human renal studies have corroborated animal data in-so-far as calcium excretion as influenced by urinary acidity is concerned. This was emphasized by Marone et al. (15) who reported increased excretion of calcium in the acidotic dog and by Zemel, et al. (27) who studied calcium filtration by the kidney. They fed subjects low or high-protein (50 or 150 g/d) diets, then compared... 

Bone. Although bone is a relatively inert tissue, it can accumulate such substances as tetracyclines, lead, strontium, and the antitumor agent cisplatin. These substances may accumulate in bone by absorption onto the bone crystal surface and eventually be incorporated into the crystal lattice. Tetracycline deposition during odontogenesis may lead to a permanent yellow-brown discoloration of teeth, dysplasia, and poor bone development. Lead can substitute for calcium in the bone crystal lattice, resulting in bone brittleness. Bone may become a reservoir for the slow release of toxic substances, such as lead and cisplatin. 

The extreme toxicity of lead results from the manifold modes of activity. In the stable state, >90% of total body lead is stored in the skeleton. Lead appears to have the capacity to seek out areas of active bone formation, where it occupies lattice interstices or exchanges with calcium in the bone... 

These chloroarsines are effective cytochrome oxidase destroyers, or blood agents. Arsenic seeks to replace calcium in the bones, thus causing bone marrow destruction as the endocrine system is concurrently attacked (Styblo and Thomas, 1997). Many organic radicals penetrate human skin, carrying their compounds with them (Cohen et al, 2006). 

Foods may contain precursors of vitamin D as well as vitamin D. The precursors are converted to the vitamin following their absorption from the diet. T c body is a source of one of the precursors, 7-dehydnocholesteroL Conversion of the precursor to the vitamin form occurs in the skin. The major function of vitamin D is to maintain the concentration of calcium ions in the plasma. Maintenance of these concentrations is vital for normal functioning of the nervous system and for the growth of bones and the maintenance of bone mass. Although vitamin D is closely associated with bone growth, it is thought that the relationship is only indirect. T he vitamin stimulates the absorption of dietary calcium by the gut, but it seems not to stimulate the subsequent deposit of calcium in the bone. 

Complexometric titrations in the clinical laboratory are limited to those substances that occur in fairly high concentrations since volumetric methods are generally not too sensitive. The most important complexometric titration is the determination of calcium in blood (see Ref. 8). Chelating agents such as. EDTA are used in the treatment of heavy-metal poisoning, for example, when children ingest chipped paint that contains lead. The calcium chelate (as Na2CaY) is administered to prevent complexation and removal of calcium in the bones. Heavy metals such as lead form more stable EDTA chelates than calcium does and will displace the calcium from the EDTA. The chelated lead is then excreted via the kidneys. 

Fluorine Hydrofluoric acid (HF) is a by-product of aluminum production by electrolysis cind the synthesis of chlorofluorocarbons (CFCs). Although in water HF is a weak acid, it s extremely toxic. HF poisoning causes deep ulceration or scarring of body tissue with a delayed effect, slowly replacing calcium in bodily tissue (flesh and bones). There s no pain at first because it s a weak acid, but when the calcium in the bones starts to be replaced by the more electronegative fluorine it feels similar to growing pains, and may be too late. Merely five-minute iexposure to 10,000 ppm concentration in the air is fatal to humans. 

Symptoms of hypocalcemia vary depending on the severity and duration of the deficiency, and in some cases, a patient even may be asymptomatic. If a patient is symptomatic, initial complaints may include numbness and/or tingling around the mouth or in the hands and feet muscles spasms in the feet, face, and hands that in more severe cases may expand to tetany (uncontrolled muscle contraction) seizures, bronchospasms accompanied by respiratory distress, and cardiac arrhythmias. Low levels of calcium in the bones may lead to disorders such as decreased bone minereralization referred to as rickets in children, osteomalacia in adults, or osteoporosis (a condition more prominent in postmenopausal women). 

The mechanism responsible for osteoporosis resulting from immobilization is not clear. One theory suggests that muscular activity stimulates osteoblastic activity in the bone. Another theory proposes that the rate of bone destruction is accelerated in osteoporosis. In immobilized innervated rat limb, there is an increased destruction in the matrix, reflected by a more rapid turnover of [ " C]glycine into the soft tissue. The increased turnover of amino acids into the protein of soft tissue is paralelled by an increased turnover by the calcium in the bone and the in the chondroitin sulfate. 

Diet may be significant. Osteoarthritis is more common among those who are past middle age-when there is a tendency to put on extra weight, to deposit less calcium in the bones, and sometimes to develop a mild form of anemia. Although these conditions are not caused by the osteoarthritis as such, they can be improved by sound nutrition. So, the doctor will probably advise the person suffering from osteoarthritis to eat more foods rich in calcium, such as milk and milk products, as well as foods containing iron and vitamins and he will advise the patient to lose weight without deprivation of any of the essential nutrients. 

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