Bone strontium

Human bone strontium levels (Fig. 1.5) are within the range that is expeeted for that region (Katzenberg 1984). The sample size is small and uneven with only three females and one subadult so it is not possible to comment on sex or age differences except to say that the highest Sr content was found in the sample from a child aged around 9 2 years. 

Recognition among bone-chemistry researchers that strontium enters bone in proportion to dietary levels has resulted in widely accepted yet erroneous inferences about the relationships among various elements in bone and past diet. One such inference is that more of any element in the diet translates directly to more of that element in bone. If an element is not biogenically incorporated within bone, or if biological levels are metabolically controlled, then that element will not reflect diet. A second erroneous inference is that strontium can be used to measure the dietary plant/meat ratio. Sr/Ca ratios in meat are generally lower than those of plants, but meat is also low in calcium and hence has little effect on the composition of bone. Plants, on the other hand, contribute substantially to bone composition. Variations in the strontium levels of bone thus more likely reflect differential consumption of plants rather than trophic position. Although efforts to determine plant/meat ratios from strontium and to draw dietary inferences from elements other than strontium and barium have not been successful, this failure has been due to inappropriate expectations, not to a failure of bone strontium to reflect diet. 

Although there are many failed attempts to determine even relative measures of meat eonsumption, the disappointment is not due to any failure of strontium to reflect diet but to an unwarranted expectation that bone strontium should necessarily reflect meat consumption. The frustration with efforts to draw paleodietary inferences stems from simplistically equating Sr/Ca ratios with plant/meat ratios and to the inappropriate use of elements not... 

Brown, A.B. 1973 Bone Strontium Content as a Dietary Indicator in Human Skeletal Populations. Ph.D. dissertation, University of Michigan, Ann Arbor. 

Bone strontium as a dietary indicator in human skeletal populations. Contributions to... 

Schoeninger, M.X and Peebles, C.S. 1981 Effect of mollusc eating on human bone strontium levels. Journal of Archaeological Science 8 391-397. 

While the strontium isotope signatures in archaeological human tooth enamel and bone from tombs at Conchopata are very similar, the five trophy heads have more heterogeneous strontium isotope signatures, as shown in Table I and Figure 1. Three trophy heads exhibit enamel and bone strontium isotope... 

In conclusion, the enamel and bone strontium isotope signatures in the trophy heads exhibit more variability than the enamel and bone strontium... 

Enamel and bone, strontium isotope analysis, 102-104 Energy dispersive spectrometry (EDS), scanning electron microscopy, Seip textiles, 35 Energy dispersive X-ray fluorescence (EDXRF), elemental analyses copper-based coins, 231-245 copper coins, Herodian prutah, 246-257... 

The distribution of the element is similar to that of calcium which means that 99% of the body burden is deposited in bone [44]. Within the dialysis population, bone strontium levels were found to be significantly higher in subjects with osteomalacia as compared to this presenting the other types of renal osteodystrophy [45]. A causal, dose-dependent role of strontium in the development of this bone disease has been established in a chronic renal failure ratmodel [46,47]. Moreover the bone osteomalacic lesions were found to be reversible after withdrawal of strontium [9,48]. 

D Haese PC, Schrooten I, Goodman WG, Cabrera WE, Lamberts LV, Elseviers MM, Couttenye M-M, De Broe ME. Increased bone strontium levels in hemodialysis patients with osteomalacia. Kidney Int 2000 57 1107-1114. 

Its inherent toxicity and that of its compounds resembles that of calcium. The state of calcium nutrition of exposed individuals is a major determinant of toxicity. The radioactive isotope, when ingested or inhaled, is processed by the body and resides in bones. Strontium ionizes molecules in the body by the emission of beta particles. It increases the risk of cancer. 

Burton, J.H., and T.D. Price. 1999. Evaluation of bone strontium as a measure of seafood consumption. International Journal of Osteoarchaeology 9 233-236. 

Experiments carried out on laboratory animals have shown that (radioactive) strontium is rapidly deposited in the skeleton, from which it is only slowly removed in the normal process of metabolism. Once ingested, of the total amount in vertebrate animals or humans more than 99 % of the strontium is localized in bone and connective tissue, which in total is about 320 mg for a 70-kg adult. For herbivorous animals the bone strontium level is higher than that present in humans, probably due to the higher dietary intake of strontium from plant material. Retention of strontium in the human body after oral doses of 100-250 mg has amounted to 12-24% in a month (Harrison et al. 1955). More strontium is absorbed by persons on a low calcium intake than on a high calcium intake. Animal as well as human studies have demonstrated that the intestinal absorptions of strontium and calcium are comparable, which led to the hypothesis that these elements share a common carrier system in the intestinal wall (Reid etal. 1986). Stron-... 

The cations Sr and Ba concentrate in the vertebrate skeleton, and the amounts of these elements vary as a function of mineral stmcture. In vivo, strontium has been found to accumulate in bone by exchange onto crystal surfaces, and is rapidly washed out after exogenous strontium is withdrawn (Dahl et al. 2001). Incorporation of strontium into the crystal lattice as a substitute of calcium occurs at a low level in vivo, in contrast to the extensive lattice substitution of strontium for calcium in fossil bone. Strontium is not easily washed out of subfossil bone (Tuross et al. 1989), and the uptake of strontium into biological apatite was once proposed as a potentially useful chronometer analogous to fluorine uptake (Turekian and Kulp 1956). The combined uptake of strontium and fluorine into vertebrate calcified tissue may in no small part account for the existence of a fossil record. Both of these elements stabilize biological apatite, and add substantially to the crystal stability of apatite under acidic conditions (Curzon 1988). 

Brown AB (1973) Bone strontium content as a dietary indicator in human skeletal populations. PhD dissertation, University of Michigan, Arm Arbor... 

The distribution of strontium is similar to that of calcium, which means that 99% of the body burden is deposited in bone (Table 1) [45-57]. In healthy adult male volunteers, the volume of distribution was estimated at 64—71 liters [58,59]. In vitro studies of strontium uptake in bone indicate that strontium is incorporated by ion exchange with calcium [60,61]. The preference of hydroxyapatite crystals to bind calcium rather than strontium seems mainly due to the larger size of the strontium ion, which produces a mild distortion of the crystal lattice and thus probably results in a weaker binding of strontium to the components of the hydroxyapatite crystal [62]. Within long bones, strontium is preferentially deposited in the shafts [63]. 

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