Calcium Interdependencies

Hannun, YA, Loomis, CR and Bell, RM (1986) Protein kinase C activation in mixedmiceUes. Mechanistic implications of phospholipid, diacylglycerol, and calcium interdependencies. Journal of Biological Chemistry, 261, 7184-7190. 

The ER has a reticular morphology which provides a large surface area, which presumably is required for the synthesis and transport of proteins and lipids and for the storage of calcium. The ER is associated with microtubules, and the two are highly interdependent structures. Terasaki et al. (1986) found that when microtubules in the cell are depolymerized by colchicine, the ER network slowly retracts toward the center of the cell. If the microtubules are repolymerized, the ER network is restored to its original morphology, thereby suggesting that the MTs participate in the formation and maintenance of the ER. 

Treatments of diseases such as osteoporosis, rickets and osteomalacia, in which there is a disturbance of phosphate levels, is complicated by the interdependence of calcium metabolism. This topic has recently been discussed in relation to clinical medicine21. There is the further difficulty that absorption of phosphate from the bowel can be decreased in the presence of calcium or aluminium salts because of the formation of their insoluble phosphates. Uptake of phosphate by bone is exploited in the treatment of polycythaemia vera by intravenous injection of 32P as sodium phosphate. The resulting irradiation of the neighbouring red bone marrow diminishes the production of red cells. 

The important role of plaque as a reservoir for active agents, such as fluoride from dental products and calcium and phosphate from saliva, is reviewed in Chapter 6. Recent findings on the dependence of the concentration and retention of these agents on plaque location are included. The relationship between plaque fluid chemistry and tooth mineral is the key to caries formation and control. This interdependence is also discussed in Chapter 3. Here both the thermodynamic approach of Margolis and coworkers and the kinetic approach of... 

Depending on which model is taken, various properties of the concrete have to be known beforehand. For example Parrotf s model [15] for prediction of corrosion initiation requires knowing the air permeability of concrete, the content of calcium oxide in the hydration products of cement and a coefficient that is a function of the relative humidity. For predicting the propagation time, the corrosion rate and the maximum acceptable corrosion penetration have to be known. In order to be able to use these models, test methods have to be clearly specified and the interdependencies between variables have to be verified. 

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