Serum strontium

Schrooten I, Elseviers MM, Lamberts LV, De Broe ME, D Haese PC. Increased serum strontium levels in dialysis patients. An epidemiological survey. Kidney Int 1999 56 1888-1892. 

Information on the distribution of strontium in soft tissue is extremely limited. In rats that were exposed to 3. 4 mg strontium/L (as SrCl2) in drinking water for 3 months, the serum concentration of strontium was 8.7 mg/L and tissue serum strontium concentration ratios (based on the latter mean serum concentration) were as follows liver, 0.7 heart, 1.2 muscle, 1.1 adrenal, 1.3 brain, 1.2 and bone, 1,300 (Skoryna 198 lb). Strontiumxalcium ratios in these tissues were approximately 0.05-0.1. Tissue plasma strontium concentration ratios in rats 1-5 hours after they received an intraperitoneal injection of strontium revealed ratios <1 in the fat, spleen, liver, ovary, testis, skeletal muscle, and heart and values of 1.2-1.7 in the lung, small intestine, salivary gland, kidney, and skin (Brues et al. 1969). Tissue plasma concentration ratios of... 

Eisenberg E. 1970. Effect of intravenous phosphate on serum strontium and calcium. N Engl J Med 282(16) 889-892. 

Several papers deal with magnesium determination in blood and urine. Willis (WIO) analyzed serum in the air-acetylene flame and found no effect from the presence of sodium, potassium, calcium, or phosphate, but states that an enhancement was seen in serum diluted with water only, probably due to serum proteins. This interference was controlled by addition of strontium or EDTA. Sensitivities were the same in the eoal gas-air and air-acetylene flame, indicating complete atomization of magnesium. In urine (W13) no interference was encountered and determinations were performed on samples directly diluted with water. 

Pybus J, Feldman FJ, Bowers GN Jr. Measurement of total calcium in serum by atomic absorption spectrophotometry with use of a strontium internal reference. Clin Chem 1970 16 998-1007. 

Strontium stimulates bone formation and decreases bone resorption. In a preliminary study of postmenopausal women with severe osteoporosis, strontium ranelate 1 g twice daily or 2 g once daily reduced new vertebral fractures by 41%, and increased lumbar spine BMD by 14% and femoral neck BMD by 8% compared with placebo. Nonvertebral fracture rates were similar. Diarrhea was more common in the strontium group. Small decreases in serum calcium and PTH, small increases in serum phosphate, and transient increases in creatine kinase were measured. 

Although trace element abnormalities occur in chronic renal failure, few symptoms have been attributed to them in nondialyzed patients. In dialysis patients these disturbances appear to be qualitatively similar but more severe (T7). They have been extensively reviewed by Alfrey (A5). Total body zinc (except in erythrocytes), strontium, aluminum, and tin are generally increased, whereas total body rubidium is decreased. Iron stores tend to be increased in the spleen and liver in dialyzed patients, especially after ferrous sulfate therapy. Copper is increased in lung tissue and decreased in heart tissue and erythrocytes. Molybdenum and cadmium are decreased in renal tissue but increased in liver tissue of dialyzed and nondialyzed patients. Total body zinc content is significantly increased (A5), but hypozincemia, frequently observed in dialysis patients, has been blamed for taste impairment and impotence and there is conflicting evidence on whether zinc repletion corrects these abnormalities (K4, Ml2). Nickel is also increased in the serum of uremic patients, but this does not appear to be associated with a corresponding increase in tissues (S5). It cannot be concluded that trace element retention in renal failure is of no clinical importance, as shown by the problem of aluminum intoxication, to be discussed later. In addition, trace elements such as rubidium and bromine, which are rapidly depleted in uremic patients on maintenance dialysis (A5), may prove to be essential in normal metabolism. Thus the clinical importance of these element alterations remains unclear. 

Biomarkers of exposure and effect are established for children. Since the primary biomarker of effect, rickets, is a late-stage phenomenon, it would be useful to establish precisely a constellation of biomarkers that would identify a precursor condition. Such markers might include relative serum levels of vitamin D, calcium, phosphorus, and phosphatases. The alginate method for reducing peak absorption of strontium has been validated in children (Sutton et al. 1971a). 

Alda JO, Escanero JF. 1985. Transport of calcium, magnesium and strontium by human serum proteins. Rev Esp Fisiol 41 145-150. 

D Haese PC, Van Landeghem GF, Lamberts LV, et al. 1996. Measurement of strontium in serum, urine, bone, and soft tissues by Zeeman atomic absorption spectrometry. Clin Chem 43(1) 121-128. 

Escanero JF, Cordova A. 1991. Effects of glucagon on serum calcium, magnesium and strontium levels in rats. Miner Electrolyte Metab 17 190-193. 

Li L, Kruszewski FH, Punnonen K, et al. 1993. Strontium induces marine keratinocyte differentiation in vitro in the presence of serum and calcium. J Cell Physiol 154 643-653. 

Lloyd E. 1968. Relative binding of strontium and calcium in protein and non-protein fractions of serum in the rabbit. Nature 217 355-356. 

Teree TM, Cohn SH. 1966. The determination of strontium in human serum using neutron activation analysis. JNucl Med 7 848-858. 

Toshioka T, Ishida M, Oami S, et al. 1974. Effects of cations on the bactericidal systems of normal rabbit serum II. Effects of calcium and strontium ions. Nihon Univ J Med 16 5-23. 

Vandecasteele C, Vanhoe H, Dams R, et al. 1990. Determination of strontium in human serum by inductively coupled plasma mass spectrometry and neutron activation analysis A comparison. Talanta 37(8) 819-823. 

Because of the scarcity of data related to strontium intake and toxicity, the World Health Organization (WHO) has not established any reference value for recommended daily intake, or proposed safe ranges for the element strontium (WHO, 1996). The data observed for Germany (Seifert et al. 2000) and other parts of the world (e.g., Pennington and Jones 1987, Schroeder et al. 1972, Skoryna 1981a) suggest that an alimentary Sr intake of 1 to 4 mg per day is very normal and without any risk. Schrooten et al. (1999) reported normal mean strontium levels in blood serum of 14 pg whereas Schroeder et al. (1972) identified a mean Sr plasma concentration of 29 pg... 

One of the most important applications of FAAS in the routine clinical chemistry laboratory is the determination of calcium and magnesium in blood serum and other body fluids. The samples are diluted 1 20 to 1 50 with a buffer such as EDTA, lanthanum, or strontium and analyzed directly in an air-acetylene flame. Paschen [6] describes a micromethod for the determination of sodium, potassium, calcium, and magnesium in a single-serum dilution. One hundred microliters of serum is diluted 1 50 with 0.25% (w/v) strontium chloride solution and analyzed directly. The addition of strontium eliminates the influence of phosphate on calcium and the ionization of sodium and potassium. 

The second important compartment for strontium is blood. Analogous to bone, the concentration is influenced by the dietary intake of strontium, calcium, and phosphate [66], Moreover, the values measured may vary strongly with the analytical technique used (Table 1). Within the blood compartment, strontium is bound by serum proteins with a maximal binding capacity of 0.128 mmol strontium/g protein (the maximal binding capacity of calcium amounts to 0.190 mmol calcium/g protein) [47,67],... 

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