Endogenic minerals

Korzhinskii, D.S. 1963. Correlation between activity of oxygen, oxidity and reduction potential in endogenic mineral formation. Izvestiya of Academy of Sciences of USSR. Geological seria. No. 3. 54-61. (In Russian)... 

It is a purely synthetic steroid which essentially exerts its action as a competitive antagonist of the potent, endogeneous mineral-corticosteroid, aldosterone. Its natriuretic action seems to be slightly more particularly in the long-term therapy. In other words, it reverses these electrolyte changes by blocking the renal tubular action of the hormone. Importantly, by critically inhibiting Na reabsorption spironolactone produces diuresis and simultaneously minimises the excretion. 

Endogenous mineral losses are often small in relation to the mineral content of the body. For example, a 30 kg pig whose body contains about 230 g of calcium loses approximately 0.9 g of calcium per day and therefore needs to replace about 0.4 per cent of its body calcium. Similarly, the same pig contains approximately 40 g of sodiiun and needs to replace 0.036 g or 0.09 per cent per day. In contrast, a pig would need to replace about 0.7 per cent of its body nitrogen per day. 

Dihydroxyvitamin (283) is the endogenous ligand for the vitamin receptor (VDR). It modulates genomic function in a tissue and developmentaHy specific manner and affects ceU proliferation, differentiation, and mineral homeostasis (74). Vitamin mobilizes calcium from the bone to maintain plasma Ca " levels. Vitamin and VDR are present in the CNS where they may play a role in regulating Ca " homeostasis. Vitamin D has potent immunomodulatory activity in vivo. 

Macdonald H, New S, Fraser W, Campbell M and Reid D. 2005. Low dietary potassium intakes and high dietary estimates of net endogenous acid production are associated with low bone mineral density in premenopausal women and increased markers of bone resorption in postmenopausal women. Am J Clin... 

The diet treatments were level of phytate intake, either 0.2 or 2.0 g/day. Each level was consumed for 15 days, three consecutive repeats of the 5-day menu cycle. To provide 2.0 g/day of phytic acid, 36 g of wheat bran was baked into 6 muffins and two muffins were eaten each meal. Dephytinized bran was prepared by incubating the bran in water and allowing the endogenous phytase to hydrolyze the phytate, then the entire incubation mixture was freeze-dried (4) and 36 g baked into 6 muffins. Thus, the intake of all nutrients and neutral detergent fiber was the same for both phytate intakes. Five subjects consumed the whole bran muffins for 15 days followed by the dephytinized bran muffins for 15 days and the other 5 subjects in the reverse order. Brilliant blue dye was given at breakfast on the first day of each collection period to aid in demarcation of stools. Stool composites were made for days 1-5, 6-15, 16-20 and 21-30 and urine composites for days 6-15, and 21-30. Daily food composites were made, homogenized, freeze-dried and then analyzed to determine mineral nutrient intakes. 

In several studies (e.g., 30-36, Table I), the effects of including "processed" fiber sources (fiber isolated from natural sources) have been investigated. Results have been contradictory for example, lOgm/day cellulose decreased zinc balances in one study (3.0) but 30 to 40g/day did not affect zinc absorption in another study (36). Processed fiber may have effects which are not indicative of the effect of a similar level of endogenous fiber from foods. In summary, daily intake levels of fiber equivalent to 20 to 30g NDF/day from food sources would not be expected to have long-term deleterious effects on mineral utilization. 

The standard diet used in our experiments is a semipurified, cholesterol-free preparation that is composed of 25% protein, 40% sucrose, 13% coconut oil, 1% corn oil, 15% cellulose, 5% mineral mix, and 1% vitamin mix. This diet has been shown to induce an endogenous hypercholesterolemia and lead to atherosclerosis in rabbits and monkeys (4, 5). The specific question addressed by our series of investigations is whether the type of dietary protein, when all other dietary components are constant, can influence the development of hyperlipoproteinemia and atherosclerosis. More specifically, we have examined the effects of the individual amino acids, lysine and arginine, and their ratios in the diet on plasma and hepatic lipids as well as the development of arterial plaques. 

To vahdate mineralization of toluene to CO under anoxic quinone and humus-respiring conditions, Cervantes et al. (2001) performed additional experiments using emiched phosphate-buffered basal sediments from Amsterdam petroleum harbor. After two weeks of incubation, 85% of added C-labeled toluene was observed as CO. Emiched sediment converted C-labeled toluene to in media supplemented with AQDS or with humic acid (Fig. 16.34A). There was negligible recovery of in the endogenous and sterile controls. The conversion of C-labeled toluene to was coupled to an increase in electrons recovered as AH QDS or as reduced humus (Fig. 16.34B). However, there was no toluene reduction in autoclaved sediments. These results indicate that humic substances... 

Fig. 16.34 Mineralization of [ C] toluene to (A) coupled to the reduction of AQDS or humus (B) by enriched Amsterdam petroleum harbor (APH) (A and B) sediments in anaerobic culture bottles containing phosphate-buffered basal medium supplemented with AQDS (5 mM) or with highly purified soil humic acids (12g/L). Uniformly C-labeled toluene was added at an initial concentration of 100p,M relative to the liquid volume. Unsupplemented controls were prepared in the same manner but without AQDS and humus. All data were corrected relative to the endogenous control (without C-labeled toluene addition). Data are means and standard deviations for triplicate incubations in each treatment d denotes days. (Cervantes et al. 2001). Reprinted with permission. Copyright American Society for Microbiology...

Bisphosphonates structurally mimic endogenous pyrophosphate, which inhibits precipitation and dissolution of bone minerals. They retard bone resorption by osteoclasts and, in part, also decrease bone mineralizatioa Indications include tumor osteolysis, hypercalcemia, and Paget s disease. Qinical trials with etidronate, administered as an intermittent regimen, have yielded favorable results in osteoporosis. With the newer drugs clodronate, pamidronate, and alendronate, inhibition of osteoclasts predominates a continuous regimen would thus appear to be feasible. 

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