Bone, calcium magnesium

The cations Mg and Ca are major components of bones. Calcium occurs as hydroxyapatite, a complicated substance whose chemical formula is Cas (P04)3 (OH). The structural form of magnesium in bones is not fully understood. In addition to being essential ingredients of bone, these two cations also play key roles in various biochemical reactions, including photosynthesis, the transmission of nerve impulses, and the formation of blood clots. 

A recent study by Sanchez et al. (1997) found significant age-related effects on aluminum interactions with essential elements (e g., calcium, magnesium, zinc). Decreases in concentration of some essential elements in a number of tissues were observed in young rats orally exposed to aluminum lactate (as compared to adults) the decreases included liver and spleen calcium levels, bone magnesium levels, and brain manganese levels. 

THE BONE MAKERS CALCIUM, MAGNESIUM, PHOSPHORUS, AND OTHERS... 

The absorption of tetracyclines from the G1 tract is non-uniform. Up to 30% of chlortetracycline is absorbed. The absorption for tetracycline, oxytetracycline, and demeclo-cycline ranges between 60 and 80%, whereas as much as 90 to 100% of doxycycline and minocycline is absorbed. The absorption of tetracyclines is impaired by divalent cations (calcium, magnesium, and ferrous iron), by aluminum, and by extremely alkaline pHs. Tetracyclines are distributed widely throughout the body fluid, cross the placental barrier, and can accumulate in growing bones. The concentrations of chlortetracycline in spinal fluid are only one fourth of those in plasma. Minocycline, a more lipid-soluble tetracycline, reaches a high concentration in tears and saliva and can eradicate the meningococcal carrier state. The tetracyclines are metabolized in the liver and excreted mainly by the bile and urine. The concentrations of tetracyclines in the bile are ten times higher than those in serum. 

Beoadus AE (1993) Physiological Junctions of calcium, magnesium and phosphorus and mineral ion balance. In Favus MJ, ed. Primer on the Metabolic Bone Diseases and Disorders of Mineral Metabolism, pp. 41-46. Raven Press New York. 

Tables 63-6.5 list some of the causes that affect plasma calcium, magnesium, and phosphate. Increased plasma calcium concentration may occur when the xeno-biotic specifically targets calcium metabolism, behaves similarly to vitamin D, and causes hyperparathyroidism or renal disease. Lead and cadmium enter bone and inhibit bone growth, increase calcium release from bone, and inhibit renal tubular reabsorption of calcium salts lead inhibits the renal bioactivation of 25-hydroxy-cholecaliciferol (Sauk and Somerman 1991). In longer-term studies, increased plasma calcium may be associated with tumor burden. Because roughly half of circulating calcium is bound to plasma albumin, hypercalcemia can also arise from dehydration. Hypoparathyroidism, pancreatitis, and renal disease can reduce plasma calcium. Acidosis increases plasma-ionized calcium concentrations, whereas alkalosis causes a decrease due to the effects of pH in the ECF or on protein binding.

Yasui M, Ota K, Garruto RM. 1991. Aluminum decreases the zinc concentration of soft-tissues and bones of rats fed a low calcium magnesium diet. Biological Trace Element Research 31 (3) 293-304. 

Kosowska, B. 1993. Effects of homozygosity and stress on blood and bone calcium and magnesium. J. Anim. Breed. Genet., 110, 140-146. 

Though magnesium has several functions in the body, one of the more important functions is its role in the absorption of calcium by cells. Magnesium, like sodium and potassium, is involved in the transmission of nerve impulses. Like calcium, magnesium is a component of bone. 

Carbonate apatite (dahllite) Calcium/magnesium carbonate/phosphate Bone... 

Carbonate apatite pLA/pLGA co-polymer Calcium/magnesium carbonate/phosphate Poly(lactic-co-glycolic) acid Bone Cartilage, bone, epithelium (gut, urogenital), hepatocyte... 

Boron is found in humans and animals. The concentrations in the organs and tissues vary. In human beings, the highest concentrations are found in the heart (28mg/kg), followed by the ribs (lOmg/kg), spleen (2.6mg/kg) and liver (2.3 mg/kg). Muscle tissue contains only 0.1 mg/kg. Boron seems to be an essential nutrient, which promotes bone formation by interaction with calcium, magnesium and vitamin D. In addition, there are indications that boron is involved in the hydroxylation of steroids, e. g., in the s)mthesis of 17P-estradiol and testosterone. The daily requirement is estimated to be 1-2 mg. Apples (40), soy flour (28), grapes (27), tomatoes (27), celery (25) und broccoli (22) are rich in boron (mg/kg solids). Important sources also include wine (8) and water. 

Magnesium. In the adult human, 50—70% of the magnesium is in the bones associated with calcium and phosphoms. The rest is widely distributed in the soft tissues and body duids. Most of the nonbone Mg ", like K", is located in the intracellular duid where it is the most abundant divalent cation. Magnesium ion is efftcientiy retained by the kidney when the plasma concentration of Mg fads in this respect it resembles Na". The functions of Na", K", Mg ", and Ca " are interrelated so that a deficiencv of Mg " affects the metaboHsm of the other three ions (26). Foods rich in magnesium are listed in Table 9. 

Fiuoride F- Not usually significant industrially Adsorption with magnesium hydroxide, calcium phosphate, or bone black Alum coagulation reverse osmosis electrodialysis... 

Magnesium and calcium are by far the most important members of the group. Magnesium is, in effect, the doorway to life it is present in every chlorophyll molecule and hence enables photosynthesis to take place. Calcium is the element of rigidity and construction it is the cation in the bones of our skeletons, the shells of shellfish, and the concrete, mortar, and limestone of buildings. 

Bone is a porous tissue composite material containing a fluid phase, a calcified bone mineral, hydroxyapatite (HA), and organic components (mainly, collagen type). The variety of cellular and noncellular components consist of approximately 69% organic and 22% inorganic material and 9% water. The principal constiments of bone tissue are calcium (Ca ), phosphate (PO ), and hydroxyl (OH ) ions and calcium carbonate. There are smaller quantities of sodium, magnesium, and fluoride. The major compound, HA, has the formula Caio(P04)g(OH)2 in its unit cell. The porosity of bone includes membrane-lined capillary blood vessels, which function to transport nutrients and ions in bone, canaliculi, and the lacunae occupied in vivo by bone cells (osteoblasts), and the micropores present in the matrix. 

Parathyroidectomy is a treatment of last resort for sHPT, but should be considered in patients with persistently elevated iPTH levels above 800 pg/mL (800 ng/L) that is refractory to medical therapy to lower serum calcium and/or phosphorus levels.39 A portion or all of the parathyroid tissue may be removed, and in some cases a portion of the parathyroid tissue may be transplanted into another site, usually the forearm. Bone turnover can be disrupted in patients undergoing parathyroidectomy whereby bone production outweighs bone resorption. The syndrome, known as hungry bone syndrome, is characterized by excessive uptake of calcium, phosphorus, and magnesium for bone production, leading to hypocalcemia, hypophosphatemia, and hypomagnesemia. Serum ionized calcium levels should be monitored frequently (every 4 to 6 hours for the first 48 to 72 hours) in patients receiving a parathyroidectomy. Calcium supplementation is usually necessary, administered IV initially, then orally (with vitamin D supplementation) once normal calcium levels are attained for several weeks to months after the procedure. 

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