Bone Strontium Research Articles

The effects of stable strontium on calcium metabolism: I. Kinetic analysis of calcium metabolism in strontium-fed rats

Stable strontium has been shown to inhibit the synthesis of 1α,25-dihydroxyvitamin D3(1,25(OH)2D3). In the present study, the effects of stable strontium on calcium metabolism were studied in growing rats. The rats were divided into control, 0.5%-Sr and 1.0%-Sr groups. After dietary treatment for 4 weeks, both intestinal calcium absorption (Vna) and the calcium absorption ratio (β) were suppressed dose-dependently by strontium. In contrast, while intestinal strontium absorption (sVna) was higher in the 1.0%-Sr group than that in the 0.5%-Sr group, there was no change in the strontium absorption ratio in the intestine (sβ). Although bone formation (Vo+) and bone resorption (Vo−) were both decreased in the strontium groups, no change was observed in the serum calcitonin and parathyroid hormone concentrations in the 1.0%-Sr group. Furthermore, a large amount of strontium deposited in newly formed bone. These results suggest that 1) the decrease of intestinal calcium absorption is due to either the reduction of 1,25(OH)2D3 synthesis or the competitive antagonistic action between calcium and strontium in the intestine, and 2) accumulation of a large amount of strontium in bone might directly inhibit bone formation and resorption.

An uncoupling agent containing strontium prevents bone loss by depressing bone resorption and maintaining bone formation in estrogen-deficient rats.

Trabecular bone loss in estrogen deficiency is associated with enhanced bone resorption with a smaller increase in bone formation. We previously reported that low doses of strontium can increase trabecular bone volume in rodents by affecting bone resorption and formation. In this study we determined the effect of a new divalent strontium salt (S12911) on bone loss induced by E2 deficiency. Sprague-Dawley female rats (230 g, n = 15-25 per group) were sham operated or ovariectomized (OVX) and treated with 17 beta-estradiol (E2, 10 micrograms/kg/day, sc) or S12911 by gavage at the dose of 77, 154, or 308 mg/kg/day or the vehicle. Treatment for 60 days with S12911 resulted in a dose-dependent increase in plasma, urine, and bone strontium concentrations without any deleterious effect on total or skeletal growth. OVX rats were osteopenic compared to sham rats as shown by decreased femoral dry bone weight and mineral content measured on bone ash and by DXA. Treatment of OVX rats with S12911 prevented bone loss as bone ash and bone mineral content were restored to the values in sham rats. Trabecular bone volume measured by histomorphometry on the tibial metaphysis was decreased by 46% in OVX rats and was corrected by E2. Treatment of OVX rats with S12911 increased the trabecular bone volume by 30-36%. Histomorphometric indices of bone resorption (osteoclast surface and number) were increased in OVX rats and were reduced by S12911 to the levels in sham rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Results of Instrument Neutron-Activation Trace-Element Analysis of Human Remains from the Naknek Region, Southwest Alaska

An attempt to replicate results of a previous dietary trace-element study of northwestern Alaska (Connor and Slaughter 1984) was made with human- and animal-bone samples from the Naknek region, southwest Alaska. Trace elements of special interest are strontium and zinc because of previously postulated relation of abundances of these elements to marine and terrestrial dietary foci in human remains from archaeological sites (i.e., Nelson et al. 1986; Schoeninger and Peebles 1981). Related objectives were to develop evidence supporting Harritt's (1988) proposal for the existence of separate late prehistoric inland and coastal social and territorial entities in the region, which would be reflected as a dichotomy of trace levels in human bone; differences in abundances of strontium and zinc trace elements in bones representing each group should reflect diets based on either terrestrial fauna and plants or largely of marine sea mammals and shellfish. We find that there are no characteristic trace-element patterns for differentiating historic and late prehistoric coastal or interior inhabitants of the Alaska Peninsula, in spite of historic and archaeological evidence that indicates that such patterns should be present. This lack of patterning is traced to an erroneous assumption made initially by the present authors, and by Connor and Slaughter (1984): Because 99 percent of all digested Sr is deposited in the skeleton of vertebrates (including marine), there is no direct correlation between Sr content of human bones and the proportion of sea-mammal or teleost consumption in the prehistoric human diet.

Rapid effects of parathyroid hormone(1–34) and prostaglandin E2 on bone blood flow and strontium clearance in the rat in vivo

The vascular effects of noradrenaline, ATP, parathyroid hormone (PTH) and prostaglandin E2 (PGE2) were investigated in the rat. Additionally, the exchange of mineral ions between bone and blood was assessed by measuring strontium clearance, with the aim of investigating whether the vascular effects of these agents altered uptake of mineral ions or if this exchange could be changed independently of blood flow. Radioactive microspheres and 85Sr were used to establish bone blood flow and mineral clearance. Measurements of bone blood flow and arterial pressure were made in each animal and used to calculate vascular resistance. A measurement of 85Sr clearance was also obtained. Arterial blood pressure was significantly affected by noradrenaline (P less than or equal to 0.003) and ATP (P less than or equal to 0.015). Additionally, noradrenaline significantly (P less than or equal to 0.03) reduced bone blood flow. This decrease was related to a significant increase in vascular resistance. Arterial blood pressure and bone blood flow were significantly reduced by both bovine PTH(1-34) (P less than or equal to 0.001, P less than or equal to 0.02) and PGE2 (P less than or equal to 0.005, P less than or equal to 0.001). Vascular resistance to bone was increased by both agents but this was only statistically significant in the case of PGE2 (P less than or equal to 0.01). A significant (P less than or equal to 0.001) reduction in strontium was also produced by PGE2. In each group the relationship between bone blood flow and strontium clearance was then analysed.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of the effects of chelation therapy with time following strontium exposure to mice

The effect of increasing the time interval between strontium exposure and chelation therapy was studied in male Swiss mice. Diethylenetriaminepentaacetic acid (DTPA), ethyleneglycol-bis-(beta-amino-ethylether)-N,N'-tetraacetic acid (EGTA), 4,7,13,16,21,24-hexaoxa-1,10-diazabycyclo[8.8.8]-hexacosane (Kryptofix 222), tartaric acid, and 1,13-bis(8-chinolyl)-1,4,7,10,13-pentaoxatridecan (Kryptofix 5) were administered intraperitoneally at 0, 6, 12, and 24 h after subcutaneous injection of 1,139 mg/kg of strontium nitrate. Chelating agents were given at doses equal to one-fourth of their respective LD50 values. Daily elimination of strontium into urine and feces was determined for five days after which time the animals were killed, and the concentration of strontium was determined in various tissues. Only Kryptofix 222 was capable of increasing the total urinary elimination of strontium when given immediately after strontium exposure, whereas the amount of total strontium excreted into the feces was significantly enhanced by treatment with EGTA at 0 or 24 h after strontium injection, or with Kryptofix 222 at 6 h after strontium exposure. However, Kryptofix 222, tartaric acid, and Kryptofix 5 reduced the concentration of strontium in bone at 0, 6, or 12 h after strontium injection, whereas at 24 h only Kryptofix 5 significantly lowered the concentration of the metal in bone. The results of this study indicate that the length of time before initiating chelation therapy for strontium removal may influence remarkably the effectiveness of this therapy.

Alterations ofin vivoelemental dietary signatures in archaeological bone: evidence from the Roonka Flat Dune, South Australia

Thermogravimetric and multi-element analyses of archaeological human rib and modem mammal controls from the lower Murray River region of South Australia indicate that magnesium, strontium, and barium concentrations in the archaeological bone have been altered significantly by post-mortem chemical reactions in the burial environment. Ionic exchanges between soil solution and buried bone resulted in lower bone magnesium concentrations and higher bone strontium and barium concentrations. Much of the remaining magnesium is associated with diagenetic calcite. Although the archaeological bone exhibits increased hydroxyapatite crystal size, the strontium and barium increases are not correlated with crystal growth. The complex interactions of these post-depositional chemical processes will complicate attempts to reconstruct in vivo elemental values from archaeological bone.

Formula omitted] as a dietary indicator in modern and archaeological bone

Strontium isotope ratios ( 87Sr 86Sr ) in human and animal bone are inherited, via foodstuffs, from rocks in the areas in which an individual lived. If such an area includes more than one rock type with differing 87Sr 86Sr , or is coastal region with terrestrial 87Sr 86Sr different from that of the sea, then bone strontium isotope ratio measurements provide a measure of the relative importance of foods from each isotopic zone. In the southwestern Cape of South Africa, marine and coastal terrestrial areas (covered by marine sands) should yield foods with 87Sr 86Sr close to the marine average, while the Cambrian and pre-Cambrian shales and sandstones of the hinterland ought to be enriched in 87Sr (from radioactive decay of 87Rb during the considerable time elapsed since they were laid down). Analyses of modern animal bones show that these patterns do prevail, furnishing us with a new means of reconstructing prehistoric diets. Preliminary measurements on archaeological human material recovered from coastal shell-midden sites apparently reflect heavy reliance on coastal foods. However, these bones have been shown to be contaminated with diagenetic marine strontium from the shells in the middens. Experiments on faunal specimens show that diagenetic strontium can be removed by repeated washing in acetic acid/sodium acetate buffer. Mineral with 87Sr 86Sr similar to the burial environment dissolves first, while subsequent washes remove strontium with different 87Sr 86Sr . For two coastal human skeletons, however, the marine/coastal terrestrial nature of the isotopic signature remains. Further experimental work is required in order to establish the limits of the technique; however, a combination of the solubility profile method and strontium isotope analysis promises to provide a powerful tool for reconstructing palaeodiets.

Biological discrimination between calcium and strontium in kidneys and bone of young and adult rats

Effects of aging on the biological discrimination between calcium (Ca) and strontium (Sr) by the kidneys and bone were studied in male and female rats of 5 to 50 wk of age by examining Sr/Ca ratios in the plasma, urine, and bone. The Ca-Sr discrimination at the reabsorption process in the kidneys was not affected by aging in male or female rats. On the other hand, discrimination between the two elements was shown to be age-related at the absorption process in the digestive tract, and became more strict with age. The reverse situation was observed in the discrimination of Ca and Sr in the femur; younger rats discriminated the two elements more strictly than older animals.

Isotope fingerprints in elephant bone and ivory

THE isotopic composition of carbon and nitrogen as well as of strontium in animal bone is related to the environment in which the animal lived1–6. It can be assumed that this is also the case for lead isotopes. In theory, therefore, we have a way of pinpointing the origin of elephant ivory, which may be of value in conservation. Here we report that by analysing the isotope ratios of these elements, a clear distinction between several different populations of the African elephant can be made.

Strontium increases and crystallinity changes in taphonomic and archaeological bone

Bone strontium levels and hydroxyapatite crystal sizes increased with time in two exposed wildebeest skeletons. The strontium increases could not be removed by sequential washing according to the method of Sillen, A. (1986). Biogenic and diagenetic Sr Ca in Plio-Pleistocene fossils of the Omo Shungura Formation. Paleobiology 12, 311–323. Human subfossil bone recovered archaeologically also showed evidence of extensive diagenetic reworking that resulted in crystal growth and elevated strontium levels. The increase in bone strontium content was independent of nonapatitic contaminating crystal phases.

Bone strontium in pregnant and lactating females from archaeological samples.

Because plants and animals consume or absorb different amounts of strontium and calcium, anthropologists are able to use strontium/calcium (Sr/Ca) ratios from archaeologically recovered human bone to estimate the relative contributions of meat and plants to paleodiets. Often females exhibit higher Sr/Ca ratios than males, a fact usually attributed to lower meat intake among women. However, in vivo and in vitro experiments with laboratory animals show that pregnancy and lactation elevate maternal bone strontium and depress maternal bone calcium because 1) strontium is discriminated against in favor of calcium in the transport of ions to the placenta and mammary glands and 2) pregnancy and lactation facilitate absorption of alkaline earth metals from the gut. In this study, bone Sr/Ca ratios and strontium concentrations were compared between reproductive-age females, postmenopausal females, and adult males from two late prehistoric Native American sites in Georgia: the King site (N = 43) and the Etowah site (N = 51). At the King site, the mean Sr/Ca ratio of females was over 14% greater than that of males. At Etowah, the mean strontium level of reproductive-age females exceeded that of postmenopausal females by almost 25%. Most of the difference, it is argued, is due to pregnancy and lactation. A dietary preference among pregnant and lactating women for foods high in alkaline earths, particularly nuts and corn, may also be partially responsible. Until we assess the influence variables other than nutrition exert on trace element concentrations, our reconstructions of paleodiets will be suspect.

Trace element analysis of human bone from the prehistoric Moriori of the Chatham Islands, with special reference to diet

Abstract Strontium and zinc concentrations in human bones from the Point Durham area of the Chatham Islands make it po sible to assess the relative importance of meat and vegetable in the ancient Moriori diet. The strontium values need to be normalised against a local faunal standard to allow meaningful comparison with other prehistoric populations. This study tends to confirm the view that this Moriori group ate few plant foods; seals and marine birds formed the basis of their economy. They ate comparatively few filter-feeding shellfish. These results do not necessarily apply to prehistoric people in other parts ofthe Chatham Islands.

Battlefield damage assessment and repair (BDAR) of electronic equipment : Richard D. Chegar. Proc. a. Reliab. Maintainab. Symp., 164 (1988)

Increased bone strontium levels in hemodialysis patients with osteomalacia.In this study, we report on the association between increased bone strontium levels and the presence of osteomalacia in end-stage renal failure patients treated by hemodialysis.We performed a histologic examination and determined the strontium content and strontium/calcium ratios in bone biopsies of 100 hemodialysis patients recruited from various centers all over the world. Aside from the bone strontium concentration, the bone aluminum content was assessed. The bone zinc concentration, a nonrelevant element for bone toxicity, was also measured.Bone strontium levels and bone strontium/calcium ratios were increased in subjects with osteomalacia when compared with those with the other types of renal osteodystrophy. Bone strontium and bone calcium levels correlated with each other. The slope of the linear regression curve correlating these parameters was much steeper in the osteomalacic group (Y = 2.22X - 120) as compared with the other types of renal osteodystrophy (Y = 0.52X - 5.7). Within the group of patients with osteomalacia, bone strontium levels also significantly correlated with the bone aluminum content (r = 0.72, P = 0.018). No such correlation was found for the other types of renal osteodystrophy. The bone zinc concentration of subjects with normal renal function did not differ significantly from the values noted for the various types of renal osteodystrophy taken as separate groups, nor could increased bone zinc concentrations be associated with a particular bone lesion.Our data demonstrate an association between osteomalacia and increased bone strontium concentrations in dialysis patients. Further studies are warranted to establish whether strontium plays either a primary, secondary, or contributive role in the development of the latter type of renal osteodystrophy.

Trophic level effects on 15N/ 14N and 13C/ 12C ratios in bone collagen and strontium levels in bone mineral

This study examines stable isotope ratios of carbon and nitrogen in bone collagen and the elemental concentrations of strontium in the bone mineral of terrestrial vertebrates from a variety of ecosystems. Documentation of the separation of trophic levels by these indices is essential for the assessment of the trophic position of prehistoric humans. Particular emphasis is given to carnivores in this study as they are generally underrepresented in most archeological assemblages. Nitrogen isotope ratios and strontium p.p.m. values can separate herbivores and carnivores depending upon the scale of the analysis. Separation is more pronounced the smaller the geographic area of the sample.

The stability of bone strontium in the geochemical environment

Past applications of bone chemistry studies to the reconstruction of human paleodiets have been limited by the inability of anthropologists to evaluate successfully the nature of diagenetic alterations of bone in the burial environment. Attempts to assess the postmortem stability of bone strontium are reviewed. A general understanding of the process of fossilization has not been achieved because much previous research resulted in the accumulation of empirical data from particular archeological and fossil sites without explicit reference to models derived from geochemical theory. One promising line of investigation involves the incorporation of geochemical models to isolate specific conditions which promote diagenesis in bone. Understanding these processes will allow the formulation of hypotheses which can be tested at various archeological sites. We stress that this approach is essential to the successful use of trace elements as paleodietary indicators.

Strontium and zinc content in bones as an indication of diet: an undergraduate project in quantitative analysis with interdisciplinary interest

The author describes a laboratory activity that addresses controversies about early human diet.

Exchange of potassium and strontium in adult bone.

The kinetics of exchange of strontium (85Sr) and potassium (42K) were studied in the mid-tibial cortical bone of 37 adult dogs. After injection of these two tracer cations and tracer-labeled albumin into the tibial nutrient artery, two types of observations were made: 1) collection of sequential venous samples to provide the outflow indicator-dilution curves and to calculate the extraction and retention at early times; and 2) detection of energy-selected gamma emissions via a detector over the tibia to give the time course of content of 42K and 85Sr in the tibia. Extractions of K+ and Sr2+ were 50 and 60% during a single transcapillary passage. More Sr2+ than K+ was retained in the first minutes. Their rates of washout over a 3-h period were similar. The interpretation is that the rate of uptake at extravascular sites is faster for Sr2+ than for K+, as is the rate of release, and that the extravascular volume of distribution for Sr2+ (adsorption sites in the interstitium or on bone) is much larger than that for K+ (intracellular).

Effect of mollusc eating on human bone strontium levels

Empirical aspects of the movement of strontium through the food chain suggest that the level of bone strontium can be used as an indicator of the percentage of meat in human diet. In general, skeletal remains from agricultural peoples are expected to have high bone strontium levels relative to hunter-gatherers from the same geographical region because plants contain relatively higher amounts of strontium when compared with animal products. The results of the study described in this paper, however, indicate that the inclusion of molluscs as a component of the diet may produce the opposite of the expected strontium values. Burials from an Archaic ( c. 2500 BC) hunting-gathering population excavated from Lu o25, an archaeological site in northern Alabama, USA, exhibit a mean bone strontium level ( X = 465 p.p.m. atomic absorption; X = 475 p.p.m. neutron activation) that is higher than the mean level from an agricultural Mississippian ( c. AD 1400) population ( X = 295 p.p.m. atomic absorption; X = 255 neutron activation) that was buried at the same site. The samples were analysed by two techniques (atomic absorption spectrometry and neutron activation analysis) and the results compared favourably; therefore, the results can be accepted as valid rather than being due to technique error. We propose that the ingestion of molluscs, whose meat is known to contain large amounts of strontium, has produced this reversal from expected results.

Transcapillary exchange and retention of fluoride, strontium, EDTA, sucrose, and antipyrine in bone.

The extractions of 85Sr2+, 18F-, sucrose-14C, EDTA-51Cr, and antipyrine-14C in bone were determined by the multiple indicator-dilution method. Fluoride and strontium extractions were 18 to 70% during a single transcapillary passage, and those of EDTA and sucrose were from 11 to 59%, whereas extraction of antipyrine was 87%. Injections of 85Sr2+ and 18F- made when perfusion was done alternately with blood and plasma resulted in similar fractional extractions. When flow and extraction were measured simultaneously, extraction was related inversely to flow.

Diet and status at Chalcatzingo: Some empirical and technical aspects of strontium analysis

Determination of the levels of particular trace elements preserved in bone provides a potential pathway for reconstructing the diet of extinct primate species and archaic human groups. Strontium is one of the most useful trace elements for dietary reconstruction but several empirical properties of strontium must be considered during the interpretation of results. (1) Strontium is distributed unevenly throughout the physical environment. (2) Plants, in general, do not discriminate against strontium. (3) During ionic transfer across biological membranes, strontium is discriminated against by terrestrial vertebrates. (4) It is unlikely that strontium would be selectively removed from bone mineral during diagenesis. A particular difficulty in trace element analysis is caused by interaction between analytical technique and sample matrix. To assess this problem the skeletal population from Chalcatzingo was analyzed by two techniques: atomic absorption spectrometry and neutron activation analysis. The results from the two techniques compared favorably indicating that the pattern of bone strontium levels could be accepted as an accurate reflection of the distribution of bone strontium within the population. After demonstrating the internal accuracy of the results, the bone strontium level and position of social rank within Chalcatzingo were compared. Ethnographic and archaeological evidence on chiefdoms and states indicate that dietary differences in the amount of meat consumed occur between social ranks. The relative social ranks were reconstructed by using a "pattern analysis" of the burial goods accompanying each individual. The individuals accompanied by jade had the lowest mean bone strontium level (X = 532). Those individuals buried with a shallow dish had a slightly higher level (X = 635). A third group, which had no grave goods, had the highest mean bone strontium level (X = 700) which suggests that their diet contained less meat than was available to the rest of the community.