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PubMed2006

Strontium binding by calcium silicate hydrates.

In the present study the binding of strontium with pure calcium silicate hydrates (C-S-H) has been investigated using batch-type experiments. Synthetic C-S-H phases with varying CaO:SiO(2) (C:S) mol ratios, relevant to non-degraded and degraded hardened cement paste, were prepared in the absence of alkalis (Na(I), K(I)) and in an alkali-rich artificial cement pore water (ACW). Two types of experimental approaches have been employed, investigating sorption and co-precipitation processes, respectively. The Sr(II) sorption kinetics were determined as well as sorption isotherms, the effect of the solid to liquid ratio and the composition (C:S ratio) of the C-S-H phases. In addition, the reversibility of the Sr(II) sorption was tested. It was shown that both the sorption and co-precipitation tests resulted in Sr(II) distribution ratios which were similar in value, indicating that the same sites are involved in Sr(II) binding. In alkali-free solutions, the Sr(II) uptake by C-S-H phases was described in terms of a Sr(2+)-Ca(2+) ion exchange model. The selectivity coefficient for the Sr(2+)-Ca(2+) exchange was determined to be 1.2+/-0.3.

Calcium Compounds↗
PubMed2003

An unexpected rise in strontium-90 in US deciduous teeth in the 1990s.

For several decades, the United States has been without an ongoing program measuring levels of fission products in the body. Strontium-90 (Sr-90) concentrations in 2089 deciduous (baby) teeth, mostly from persons living near nuclear power reactors, reveal that average levels rose 48.5% for persons born in the late 1990s compared to those born in the late 1980s. This trend represents the first sustained increase since the early 1960s, before atmospheric weapons tests were banned. The trend was consistent for each of the five states for which at least 130 teeth are available. The highest averages were found in southeastern Pennsylvania, and the lowest in California (San Francisco and Sacramento), neither of which is near an operating nuclear reactor. In each state studied, the average Sr-90 concentration is highest in counties situated closest to nuclear reactors. It is likely that, 40 years after large-scale atmospheric atomic bomb tests ended, much of the current in-body radioactivity represents nuclear reactor emissions.

Child↗
PubMed2001

Effect of temperature on the uptake of waterborne strontium in the common carp, Cyprinus carpio (L.).

The effect of temperature on the uptake kinetics of strontium (Sr) in the common carp (Cyprinus carpio) was studied in vivo, exposing pre-acclimated fish to a wide range of Sr concentrations in water (Sr(total)=0.2-10,000 microM; Ca(total)=348 microM) at 10, 20, 25 and 30 degrees C. Sr uptake rates were determined in the whole body, gills and blood of the fish after an exposure period of 3 h and were analyzed as a function of the free-ion activity of Sr and Ca in water. The uptake of Sr(2+) by the whole body, gills and blood increased with temperature and showed saturation kinetics with the increase of Sr(2+) activity. Analyzing the observed uptake rates with a Michaelis-Menten type model showed that the kinetic parameters (J(max), K(m) and K(i)) for both Sr(2+) and its analogue Ca(2+) are temperature dependent. Thermodynamic analysis of the temperature effects indicates that the Arrhenius activation energies (E(a)) required for Sr(2+) uptake (91.9 kJ mol(-1)) and Ca(2+) uptake (105.9 kJ mol(-1)) in the whole body of carp were constant over the temperature range 10-25 degrees C and showed a break in the Arrhenius plots above this temperature. The Arrhenius plot for the Sr(2+) uptake in blood was similar to that for the whole body uptake with an E(a) of 98.1 kJ mol(-1). However, the E(a) for Sr(2+) uptake in gills was much smaller and constant (58.1 kJ mol(-1)) over the temperature range of 10-30 degrees C. For a temperature change from 10 to 25 degrees C, the Q(10) for Sr(2+) uptake in whole fish, gills and blood were 3.71, 2.29 and 4.05, respectively. Compared with Ca(2+) uptake, Sr(2+) uptake appears to require a lower activation energy for transport across the solution body interface in carp. The similar pattern of Arrhenius plots and magnitude of activation energies for Sr(2+) uptake both in blood and whole fish suggest that the uptake into the blood across the basolateral membrane is the rate-limiting energy barrier and hence dictates the overall uptake rate of Sr(2+) in whole fish.

Animals↗
PubMed2002

Bioavailability of waterborne strontium to the common carp, Cyprinus carpio, in complexing environments.

The uptake of strontium (Sr) and calcium (Ca) in the common carp, Cyprinus carpio, was studied in chemically defined freshwater in the presence of the complexing ligands, ethylenediaminetetraacetic acid (EDTA), and nitrilotriacetic acid (NTA). The uptake rates were measured in the whole body, gills, and blood of the fish after an exposure period of 3 h. The uptake rates were determined by using the radiotracers (85)Sr and (45)Ca, and analyzed as a function of the free-ion activity of Sr and Ca in water. Although Sr(2+) activity decreased, the uptake of Sr showed an increase at relatively low concentrations of EDTA and NTA, and a decrease at relatively high concentrations. This can be explained by the decreased competition between Sr(2+) and Ca(2+) at the gill uptake sites due to approximately 30-140-fold higher affinity of EDTA and NTA for Ca(2+) than Sr(2+). With decreasing Ca(2+) activity, Ca uptake rates decreased in the presence of EDTA and NTA, but the effect of NTA was less pronounced. A Michaelis-Menten type competitive inhibition model was derived that could predict the whole-body Sr and Ca uptake rates, taking into account the ambient Sr(2+) and Ca(2+) activities in the presence of EDTA. In case of NTA, the uptake rates were found to be 1.5-3.2 times higher than what was predicted by the model. When the fish were exposed to complexing environments in the complete absence of Ca, an increased uptake of Sr was still observed in case of NTA, but not EDTA. The increased uptake in the presence of NTA is attributed to the direct uptake of SrNTA(-) and CaNTA(-) complexes from water. The results reveal that the uptake of Sr and Ca in carp is not merely a function of the free metal-ion activity but that certain complex species may contribute significantly to overall uptake.

Animals↗
PubMed1994

Stable strontium absorption as a measure of intestinal calcium absorption: comparison with the double-radiotracer calcium absorption test.

1. Stable strontium (Sr) has been proposed as an alternative to calcium (Ca) isotopes for the measurement of intestinal Ca absorption. The aim of this study was to compare the time course and fractional absorption of Ca and Sr, when both are measured using dual-tracer techniques. 2. 45Ca and Sr absorption tests were carried out on consecutive days in patients with osteoporosis (n = 10) or chronic renal failure (n = 7). Both tests were repeated in four patients with chronic renal failure after treatment with calcitriol (1 microgram daily for 10 days). 3. The time course of Ca absorption was determined using the 85Sr (intravenous)/45Ca (oral) dual-tracer technique, and the time course of Sr absorption using 85Sr (intravenous)/stable Sr (oral). Oral tracers were administered on consecutive days with a test meal containing 5.3 mmol of Ca and 2.5 mmol of either stable Sr or Ca carrier. The fractional absorption of 45Ca and Sr at 6h (FA360) and the absorption rate as a function of time were calculated by deconvolution. 4. The mean FA360 for Sr (20.2%) was lower than the mean FA360 for 45Ca (37.8%, P < 0.001, paired t-test), but the time course of Sr absorption was similar to that of Ca. There was a significant correlation between the FA360 for 45Ca and Sr, although the relationship was improved by including a quadratic term (R2 = 0.89, P < 0.001, significance of quadratic term, P < 0.05). After 1,25-dihydroxyvitamin D treatment, the FA360 of stable Sr increased 4.29-fold, whereas the FA360 of 45Ca increased only 2.4-fold.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2001

Less pain does equal better quality of life following strontium-89 therapy for metastatic prostate cancer.

93 patients with hormone refractory metastatic prostate cancer were entered on a prospective study to measure reduction in pain and changes in quality of life (QoL) after the administration of 150 MegaBequerel (MBq) Strontium-89 (Sr-89). QoL was assessed using a validated instrument, the Functional Living Index - Cancer (FLIC) questionnaire. Pain response was measured using the Radiation Therapy Oncology Group scoring system. Overall there was limited QoL improvement over 3 months following Sr-89. However, in the 53 patients (63%) achieving pain responses, QoL did significantly improve within 6 weeks of receiving Sr-89 compared to patients with stable or worsening bone pain, and this was independent of other parameters that might influence QoL outcomes, such as performance status, baseline PSA and extent of skeletal disease (P = 0.004). PSA 'response' occurred in 30 patients (37%) over 4 months after Sr-89. This did not appear to correlate with clinical improvement. This study supports the presumption that improvement in pain following Sr-89 is accompanied by better QoL. The lack of correlation of PSA response and clinical parameters indicates that in the palliative setting, PSA may not provide a useful surrogate for treatment outcome.

Bone Neoplasms↗
PubMed1986

Hematologic depression following therapy with strontium-89 chloride.

Initial clinical trials using strontium-89 (Sr-89) chloride for the treatment of painful skeletal metastases have observed minimal or no hematological depression secondary to the radiostrontium. A patient with marked bone marrow depression temporally related to the administration of the Sr-89 is reported, and the need for close hematological monitoring is emphasized. Bone marrow tumor replacement may predispose patients to marrow depression from radiostrontium, and such patients should be treated with caution.

Aged↗
PubMed1966

The effect of the replacement of calcium by strontium on excitation-contraction coupling in frog skeletal muscle.

1. In frog skeletal muscle strontium can replace calcium in potassium contractures for 5 hr, though it is less effective than Ca. Sr can restore the responsiveness to K after it had been lost in the presence of Mn.2. Muscles refractory to caffeine following repeated exposure to it in the absence of Ca, recover in part following addition of Sr.3. The uptake of (85)Sr was increased during mechanical activity, whereas the uptake of (58)Co was not changed. Resting uptake of (58)Co was 3-4 times greater than that of (85)Sr.4. Sr fully activated the myofibrillar adenosine triphosphatase (ATP-ase), though its affinity was about 30 times less than Ca.5. The sarcoplasmic reticulum took up Sr, though less effectively than Ca.

Adenosine Triphosphatases↗
PubMed1972

The passage of calcium and strontium across the gut of the anaesthetized goat.

1. The translocation of calcium and strontium across the intestine of the anaesthetized goat has been studied. It has been found to be unaffected by ouabain, by the absence of sodium, by a severely hypertonic environment and by heparin and chondroitin sulphate. Thus it is unlikely that, in the intact goat, the trans-mucosal sodium and calcium transport systems are interrelated.2. The effect of sodium alginate both on the rate of absorption and the calcium/strontium discrimination ratio has been confirmed.3. The movement of calcium ion in both directions across the intestinal mucosa has been studied and evidence for the active transport of calcium adduced.

Alginates↗
PubMed1961

Strontium-90 and cesium-137 in North American milk.

The strontium-90 and cesium-137 concentrations in powdered milk in North America vary roughly with the specific activity of rain. The Sr(90)/Cs(137). ratios in over 800 powdered milk samples taken from 60 stations in North America from 1957-60 have a standard deviation of only 44 percent.

Animals↗
PubMed1962

Strontium-90 fallout from the 1961 Soviet nuclear detonations.

A steady increase in the strontium-90 concentration in rain was observed at Fayetteville, Arkansas, after the 1961 Soviet nuclear test series. Experimental data indicate that the nuclear weapons tested in 1961 were "cleaner" on the average by a factor of five than those exploded in 1957 and 1958.

Arkansas↗
PubMed1962

Uptake of strontium-85 by alfalfa.

Experiments with alfalfa were carried out to study the possibility of changes with time in the availability of radiostrontium in soil. After the soil was treated once with Sr85, the first crop was harvested after 60 days of growth. Four subsequent crops, cut at successive 4-week intervals, were examined. The difference in uptake between the second and fifth crops was statistically significant, suggesting that some fixation of Sr85 may occur in the soil. The effects of various applications of ammonium dihydrogen phosphate, monocalcium phosphate, calcium chloride, and potassium chloride on the uptake of Sr85 by alfalfa were also investigated. Of the experiments carried out, only the treatment with 1.0 meq of potassium per 100g of soil resulted in a statistically significant reduction in strontium uptake.

Medicago sativa↗
PubMed1994

Strontium-89 (Metastron) in the treatment of prostate cancer metastatic to bone.

Bone metastases that develop in patients with advanced prostate cancer often cause deep, unremitting pain. Palliative options for the control of this pain include analgesic support, cytotoxic chemotherapy and external-beam radiotherapy. In addition to external irradiation, interest in intravenously injected radioisotopes that are preferentially localized to bone has been mounting. Metastron (an isotope of strontium) imitates the biodistribution of calcium in vivo and is avidly taken up into bony metastases where it has a biological half-life of just over 50 days. The biological half-life in undiseased bone is far shorter, approximately 14 days. Various studies have been conducted to evaluate the role of Metastron in metastatic prostate cancer. An optimum dose has yet to be finalized, but it is clear that the change of haematological toxicity becomes more significant at much larger doses. In the large, randomized Trans Canada study in which Metastron or placebo was given to patients as an adjunct to local field irradiation, those patients treated with Metastron had a significantly reduced intake of analgesics. Furthermore, progression of pain, as measured either by sites of new pain or by the requirement for further palliative radiotherapy, demonstrated statistically significant differences in favour of Metastron. There is thus increasing evidence of a useful role for Metastron in the treatment of prostate cancer metastatic to bone.

Antineoplastic Agents↗
PubMed2001

[Internal strontium-89 radiotherapy for malignant bony metastasis].

OBJECTIVE: This work was done to evaluate the indication, effectiveness, and side effects of internal radiotherapy with radioactive nuclide strontium-89 (89Sr) in patients with malignant metastasis in the bone. METHODS: Fifty-six patients with skeletal metastasis received this internal radiotherapy. The patients were observed and followed up with respect to pain control, lesion improvement and side effects. RESULTS: The overall effective rate of pain control was 76.8% with the effective rate of prostatic cancer and breast cancer higher than 80%. The lesions in 81.8% patients as assessed by SPECT imaging, were improved. The mild lowering of white cells, platelets and red cells was the main side effect. CONCLUSION: Internal radiotherapy with 89Sr is very useful for patients with malignant cancer metastasis in the bone.

Adult↗
PubMed2002

Strontium 89 in the treatment of pain due to diffuse osseous metastases: a university hospital experience.

More than two-thirds of the patients with osseous metastases experience debilitating bone pain, requiring some form of pain relief. Analgesics are limited in their efficacy. Palliative application of hemi-body external beam radiation therapy in the treatment of multiple osseous metastases also is limited due to toxicity associated with large treatment ports. Intravenous injections of bone seeking radioisotopes are effective in the palliation of pain with fewer side effects. Forty-one patients with multiple osseous metastases due to prostate and breast cancer were treated with strontium chloride 89 (89Sr) at the department of radiation oncology, in a university hospital. A retrospective analysis of these patients indicated that all subjects had severe pain that diminished their quality of life. Most of these patients had multiple co-morbid factors. Many were on opioids leading to adverse effects such as nausea, constipation, and drowsiness that required additional medication. Objective findings and evaluation of the responses were not always available for all patients. Following treatmentwith 89Sr, over two-thirds of the patients responded favorably and required lower doses of opioids.

Black or African American↗
PubMed1985

Strontium-85 in the fetuses of pregnant rats and mice.

Pregnant SPF Wistar rats and ICR/Swiss albino mice were injected in the tail vein with 85SrCl2 with 0.05 mM inactive carrier (SrCl2) given in volumes of 0.1 ml. The activity in the injected volume was about 14 MBq per kg of rat and 13 MBq per kg of mouse. The animals were injected at 2 or 13 days of gestation. The activity retained by the fetuses was quantitatively determined at three stages of the fetal intrauterine development: in rats at 14, 16 and 21 days of gestation, in mice at 14, 16 and 20 days of gestation. The activity of fetuses and/or placentas with fetal membranes was measured using a TESLA automatic gamma counter. Results indicate that fetuses of mice retained a significantly (P less than 0.01) greater percent of strontium activity than fetuses of rats. The highest specific activities (the percentage of total activity retained per gram of fetal tissue) were found in the late pregnancy period (at 21 days of gestation in rats and 20 days of gestation in mice) in animals that were injected with the radionuclide at 13 days of gestation.

Animals↗
PubMed1995

Strontium 89 therapy for the palliation of pain due to osseous metastases.

OBJECTIVE: To present the current state of systemic radiopharmaceutical therapy for the palliation of pain in individuals with metastatic cancer and to evaluate the palliative effect and degree of hemotoxicity of strontium chloride 89 (89Sr) in patients with painful osteoblastic metastases primarily from prostate and breast cancer. DATA SOURCES AND STUDY SELECTION: A MEDLINE search through December 1994 was performed to identify English-language studies that met the following criteria. All eligible studies reported treatment of patients with painful osteoblastic bony metastases primarily from prostate or breast cancer treated with intravenous 89Sr. For study eligibility, evaluation of clinical response as assessed by the Karnofsky index, need for pain medication, or changes in mobility or sleep patterns was required. Hemotoxicity data were a requirement. A minimum of 10 prostate cancer cases was necessary for study inclusion. Only those studies assessing clinical response following one injection of 89Sr were included. Preliminary reports of cooperative studies were not included. Doses of 89Sr ranged from 0.6 MBq/kg (16 microCi/kg) to 400 MBq (10.8 mCi) per patient. Evaluation of patients for at least 3 months following 89Sr treatment was required. In addition, two studies examining issues of cost with regard to 89Sr treatment were identified. DATA EXTRACTION: Baseline pain assessment and periodic pain estimates as measured by the Karnofsky index, medication diaries, changes in mobility, sleep patterns, and/or ability to work were the basis for assessment of response. Baseline and periodic complete blood cell counts were the basis for hemotoxicity evaluation. DATA SYNTHESIS: Palliation and hemotoxicity data were analyzed separately for each study. Some improvement occurred in as many as approximately 80% of patients. Several studies demonstrated complete relief of pain in at least 10% of patients The nadir of platelet and white blood cell counts appears at approximately 4 to 8 weeks following injection, with a partial return to baseline by 12 weeks. As many as 10 injections spaced 3 months apart have been given to some patients with repeated palliative effect and without serious hemotoxicity. Reinjection may be limited by a platelet count below 60 x 10(9)/L, a white blood cell count below 2.4 x 10(9)/L, or the absence of osteoblastic skeletal metastasis as seen on bone scan. Studies examining treatment costs suggest that 89Sr may decrease costs associated with palliation of pain due to metastatic disease. CONCLUSIONS: As many as 80% of selected patients with painful osteoblastic bony metastases from prostate or breast cancer may experience some pain relief following 89Sr administration. In addition, as many as 10% or more may become pain free. Duration of clinical response may average 3 to 6 months in some cases. Hemotoxicity is mild. A decrease in treatment costs with administration of 89Sr to patients with painful osteoblastic bony metastases from prostate cancer may occur. These observations reflect the preliminary nature of knowledge in this field and point to the need for larger clinical trials of the use of 89Sr palliation.

Bone Neoplasms↗
PubMed1995

Palliation of bone pain in patients with metastatic cancer using strontium-89 (Metastron).

Bony metastasis is the most common cause of cancer pain. Strontium-89 (Sr-89), or Metastron, therapy has been shown to be effective for the palliation of pain due to skeletal metastases. By reducing opioid analgesics intake and restoring mobility, Sr-89 improves the patient's quality of life. Sr-89 is given conveniently as an outpatient procedure, and when necessary it can be repeated at 3-month intervals. Sr-89 is useful as an adjunct to local external beam radiation (EBR) because Sr-89 will target all skeletal metastases, including those not included in the EBR field. Because Sr-89 is a beta-emitting radionuclide with a long physical half-life (50.5 days), precautions should be taken by the caretaker(s) against Sr-89 contamination from the patient's blood or excretions, particularly if the patient is incontinent.

Bone Neoplasms↗