Phosphorus restriction

The first-line treatment for the management of hyperphosphatemia is dietary phosphorus restriction to 800 to 1000 mg per day in patients with stage 3 CKD or higher who have phosphorus levels at the upper limit of the normal range or elevated iPTH levels.39 Foods high in phosphorus are also high in protein, which can make it difficult to restrict phosphorus intake while maintaining adequate protein intake to avoid... 

Phosphorus is provided as sodium or potassium phosphate in PN. Approximately 10 to 15 mmol of phosphate are needed per 1000 kilocalories to maintain normal serum phosphorus concentrations (provided the patient is well nourished and has normal renal function).15 Patients with renal insufficiency may require phosphorus restriction. 

Dietary phosphorus restriction (800 to 1,000 mg/day) should be first-line intervention for stage 3 or higher CKD. 

Adhere to a dietary regimen of calcium supplementation and phosphorus restriction avoid excessive use of aluminum-containing compounds... 

Yi H, Fukagawa M, Yamamoto H et al. (1995) Prevention of enhanced parathyroid hormone secretion, synthesis and hyperplasia by mild dietary phosphorus restriction in early chronic renal failure in rats. Possible direct role of phosphorus. Nephron 70 242-248... 

Slatopoisky E, Finch J, Denda M, Ritter C, Zhong M, Dusso A, et al. Phosphorus restriction prevents parathyroid gland growth. High phosphorus directly stimulates PTH secretion in vitro, J Clin Invest 1996 97 2534-40. 

Management of hyperphosphatemia, calcium balance, and secondary hyperparathyroidism includes dietary phosphorus restriction, use of phosphate binding agents, and vitamin D therapy. 

Fluid and electrolyte disorders and metabolic acidosis are primarily the result of altered transport mechanisms within the kidney and decreased elimination of solutes (see Chaps. 49, 50, and 51). Malnutrition may also occur as dietary changes such as phosphorus restriction are implemented. Foods high in phosphorus are generally also high in protein therefore restriction of these protein sources contributes to malnutrition. Malnutrition may also develop due to decreased appetite in those with severe kidney disease. The likelihood of developing these secondary complications and comorbidities increases as GFR declines. 

Patients with CKD or ESKD often are treated for hyperphosphatemia with phosphorus-restricted diets and phosphate binding agents (see Chaps. 43 and 44). When these patients receive aggressive nutritional support, the combination of refeeding (cellular uptake of phosphorus for synthesis of body cell mass) and vigorous phosphatebinding therapy can result in hypophosphatemia. 

Dietary modification depends on the type of stones formed. The formation of calcium phosphate stones may be lessened by a calcium- and phosphorus-restricted diet, and by aluminum gel which diminishes the absorption of phosphoms. Modification of the urine pH also prevents the formation of kidney stones. An acid urine helps prevent stones of calcium and magnesium phosphate and carbonates, while an alkaline urine helps prevent oxalate and uric acid stones. The diet should support therapy with alkalinizing or acidifying agents by supplying acid-producing or alkaline-producing foods. Also the formation of uric acid stones may be lessened by a purine-restricted diet. 

These a-acylaminoketones also provided a convenient synthesis of thiazoles on treatment with phosphorus pentasulfide (Gabriel s method). Although yields range from 45 to 80%, substituents are usually restricted to alkyl, aryl and alkoxy derivatives. Thus, reaction of the a-acylaminoketone (4) with P4S1Q gave the thiazole (5), and thiazole (7) itself was prepared in this manner in 62% yield from formylaminoacetal (6) (14CB3163). The corresponding 5-ethoxy compound was obtained from the a-formamidoester and phosphorus pentasulfide in an inert solvent. 

Phosphorus appears to have a beneficial effect on the growth rate. At sub-critical temperatures it helps to stabilise the carbide, while at temperatures up to about 900°C the presence of the hard phosphide eutectic network restricts the deformation to which the much more ductile matrix would otherwise be subject. Since the phosphide eutectic melts at about 950°C, irons containing appreciable amounts of this constituent should clearly not be exposed to this temperature. 

In the presence of suffident metal ions such as zinc, phosphate defidency is known to inhibit growth and increase yields of dtric add. However, phosphate is added not only as a source of phosphorus but also as phosphoric add to addify the medium. Restricted growth but good citric add yield is also achieved by maintaining iron and zinc defidency hence low phosphate levels are not necessary. 

To be useful as CVD precursors, a metallo-organic compound should be stable at room temperature so that its storage and transfer are not a problem. It should also decompose readily at low temperature, i.e., below 500°C. The compounds listed in Table 4.1 meet these conditions with the exception of the alkyls of arsenic and phosphorus, which decompose at higher temperatures. For that reason, the hydrides of arsenic and phosphorus are often preferred as CVD precursors (see Ch. 3). These hydrides however are extremely toxic and environmental considerations may restrict their use. 

Fig. 14-5 Typical distribution of P and temperature in a temperate lake in summer. Thermal stratification restricts exchange between surface and deep wafers. Phosphorus is depleted in the surface waters by the sinking of biologically produced particles.

Other workers have used the fused ring system (104) and 4,5-dimethyl substitutions (105) to simplify n.m.r. studies by restriction to one chair form. In each case the stable configuration had an axial alkoxy-group at phosphorus. 

The extent of restricted rotation about the amide band of (38) was used to compare the electron-withdrawing process of phosphonium salts (38, Y = alkyl) and chalcogenides (38, Y = O or S) with the more conventional electron-withdrawing groups. These phosphorus groups were found to exert a — A7 effect comparable with that of a nitro-group. 

Restricted rotation has been observed in tris-o-tolylphosphine sulphide and selenide (39). The spectrum of the selenide shows two methyl environments in the ratio 2 1 at 30 °C but the methyl signals of the sulphide resolved to this pattern only upon cooling the sample. The corresponding oxide and the parent phosphine showed only one methyl environment down to — 60 °C. Y-Ray diffraction of the selenide showed that the methyl group on one aryl group is directly behind the phosphorus atom in the crystal, as shown in (39). 

Dietary and phosphorus-containing medication restriction ° Protein restrict to 0.6-0.8 g/kg/d... 

Phosphate-Binding Agents When serum phosphorus levels cannot be controlled by restriction of dietary intake, phosphate-binding agents are used to bind dietary phosphate in the GI tract to form an insoluble complex that is excreted in the feces. Phosphorus absorption is decreased, thereby... 

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