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The element Strontium takes its name from the village of Strontian in Argyll. It was in ore samples taken from lead mines near the village that Strontium was first identified as a new element in 1970. A radioactive form of the element has reached medical prominence through its use in the palliation of pain in patients with painful skeletal metastases.
A cytochemical procedure for the localization of adenylate cyclase with Sr2+ as the capture ion and adenylyl imidodiphosphate as the specific substrate was evaluated in the rat pancreas. Incubation medium was unaffected by the addition of 5 mM strontium ions but became turbid in the presence of lead or strontium plus 10 mM NaF. Tissues were prefixed in 2% formaldehyde/0.5% glutaraldehyde and incubated, and the cytochemical precipitate was converted to the Pb2+ salt. Enzymatic activity was demonstrated on the plasma membrane of pancreatic acinar cells and responded to stimulation by secretin. Controls frequently contained Pb2+ sequestered in mitochondria, but otherwise only a few randomly distributed grains were observed. The controls were 1) omission of substrate from the medium; 2) incubation of tissue for 1 min in complete medium; and 3) tissue previously inactivated by microwave irradiation and incubated for 30 min in complete medium including secretin.
Data from beagle experiments and radium dial painters were used to derive two-mutation carcinogenesis models for bone cancer induced by the bone-seeking radionuclides radium, strontium and plutonium. For all data, the model fits indicate that at low doses both mutation rates depend linearly and equally strongly on dose rate. For the high-LET alpha-particle emitters, a cell killing term reduces the second mutation rate at high dose rates. In all cases, the combined effect of both mutation rates is a linear-quadratic dose-effect relationship for cancer at low doses. This behavior may lead to experimental data that could be mistaken as showing a threshold below which no cancers are induced. Derived parameters such as toxicity ratios and tumor growth times compare well with values reported in the literature. Furthermore, results for plutonium indicate that rapid burial of the nuclide in the growing bones of juvenile beagles leads to a significant reduction of its toxicity, as was suggested previously. The results for radium in beagles compare well with those for humans and suggest that the models derived for strontium and plutonium in beagles may be translated to humans. The significant model parameters for the accurate animal data could then also be used to fit human epidemiological data.
Sixty adult patients were examined for dentin hypersensitivity prior to periodontal surgery. Stimuli used included mechanical, cold water and compressed air blasts. A subjective assessment of the degree of hypersensitivity for each stimulus was recorded. This presurgical examination revealed 249 hypersensitive areas among 60 subjects. Following surgery there was over a 100% increase in the pain (hypersensitivity) score. Desensitization with a 10% strontium chloride hexahydrate dentifrice was begun 1 week after surgical treatment. After 7 weeks of dentifrice use the pain score was reduced 75.5% in the test group. This was a reduction to a point below the preoperative level. The placebo group showed a reduction of 34.2% which was still above the preoperative level. These results agree with other clinical studies that have demonstrated a desensitizing effect of strontium chloride.
Groups of male CBA-mice were treated with oestrogenic hormones alone or in combination with 85Sr and 90Sr. The strontium retention was measured in special skeleton parts and also by means of whole body counting. After a period of increasing bone weight in mice treated with oestrogen and 90Sr, there were signs of a serious breakdown of that newly formed 'oestrogenic' bone tissue. The strontium retention was in no case found higher in animals treated with both the hormones and 90Sr when compared to those treated with 90Sr alone. The life span was shortened in mice given the combined treatment. The results support the theories that at the same time irradiated and stimulated cell populations are exposed to a larger risk for induction of tumours and that the irradiation injury cannot be referred entirely to the irradiation dose in a physical sense.
Pregnant CBA mice were intravenously contaminated with radiostrontium (85Sr) on either the 14th, 16th or 18th day post coitum. The radiostrontium content in the foetuses and corresponding placentas as well as that in the femurs of the mothers was measured separately and individually on the 19th day post coitum, i.e. after intervals of 5, 3 and 1 day, respectively. The retained amount of strontium in the foetuses successively increased by the time of contamination, i.e. the later during pregnancy the contamination occurred. Expressed as per cent of the injected amount of 85Sr, the figures ranged from 4.6 per cent in foetuses contaminated on the 18th day to 0.7 per cent for those contaminated already on the 14th day after coitus, with a significantly negative correlation between time and retained amount of radiostrontium. The amount of strontium in the femurs of the mothers was reduced within the same intervals, due partly to decalcification of the skeleton of the mother during the latest part of the pregnancy.
Control and streptozotocin diabetic rats were studied at 5 and 12 days after induction of diabetes. Strontium absorption was measured by in situ perfusion of duodenum and ileum. Duodenal absorptive capacity (absorption per unit length) and absorptive specific activity (absorption per gram of dry weight mucosa) were depressed. Depression was present both at 5 days, when mucosal growth is similar in controls and diabetics, and at 12 days, when mucosal growth is 50% greater in diabetics. Effects of diabetes on ileal absorption were minimal in comparison with effects on duodenum. This depression of duodenal strontium absorption in the diabetic rat is analogous to effects of diabetes on calcium absorption and may be mediated by abnormal vitamin D metabolism.
The Chernobyl accident and its resultant radioactive pollution of enormous areas led to long-term entrance of radionuclides into the human habitat. Among more than 200 radionuclides, the products of uranium fission in the reactor of the atomic power station, the isotopes of iodine, cesium, and strontium present the highest hazard. If iodine-131 virtually decayed by August, 1986, the long-lived isotopes of cesium and strontium will still stir the world public and scientists for many years. The authors' result show that new types of dietary cellulose and composite food additives based on alfalfa polymers have rather pronounced antiradioactive properties against Cs-137 and Sr-85. This makes it necessary to organize the manufacture of these food additives whose daily dose of 12-20 should be supplemented into human diet every day.
Four patients (men aged 75, 67, 65 and 69 years) with painful osseous metastases from prostate cancer were treated by intravenous radionuclide therapy using Strontium-89. All had secondary progression after initially successful hormonal treatment. Three of these four had good responses lasting from 5 to 9 months. One patient with rapidly progressive disease did not respond. Second and third injections were successful in two patients. Mild bone marrow suppression was observed in all, but was not clinically significant. The 70-80% chance of long-lasting pain alleviation through a single injection of Strontium-89 is a valuable addition in the treatment of painful bone metastases from prostate cancer, and probably also in such metastases from breast cancer.
BACKGROUND: Little is known about trace metal alterations in the bones of dialysis patients or whether particular types of renal osteodystrophy are associated with either increased or decreased skeletal concentrations of trace elements. Because these patients are at risk for alterations of trace elements as well as for morbidity from skeletal disorders, we measured trace elements in bone of patients with end-stage renal disease. METHODS: We analyzed bone biopsies of 100 end-stage renal failure patients enrolled in a hemodialysis program. The trace metal contents of bone biopsies with histological features of either osteomalacia, adynamic bone disease, mixed lesion, normal histology, or hyperparathyroidism were compared with each other and with the trace metal contents of bone of subjects with normal renal function. Trace metals were measured by atomic absorption spectrometry. RESULTS: The concentrations of aluminum, chromium, and cadmium were increased in bone of end-stage renal failure patients. Comparing the trace metal/calcium ratio, significantly higher values were found for the bone chromium/calcium, aluminum/calcium, zinc/calcium, magnesium/calcium, and strontium/calcium ratios. Among types of renal osteodystrophy, increased bone aluminum, lead, and strontium concentrations and strontium/calcium and aluminum/calcium ratios were found in dialysis patients with osteomalacia vs the other types of renal osteodystrophy considered as one group. Moreover, the concentrations of several trace elements in bone were significantly correlated with each other. Bone aluminum was correlated with the time on dialysis, whereas bone iron, aluminum, magnesium, and strontium tended to be associated with patient age. Bone trace metal concentrations did not depend on vitamin D intake nor on the patients' gender. CONCLUSIONS: The concentration of several trace elements in bone of end-stage renal failure patients is disturbed, and some of the trace metals under study might share pathways of absorption, distribution, and accumulation. The clinical significance of the increased/decreased concentrations of several trace elements other than aluminum in bone of dialysis patients deserves further investigation.
BACKGROUND: Strontium is known to affect calcium metabolism both experimentally and in clinical studies on conditions other than end-stage renal failure (ESRF) and continuous ambulatory peritoneal dialysis (CAPD). OBJECTIVE: To investigate Sr metabolism in relation to that of Ca in ESRF patients undergoing CAPD, and the possible influence of the duration of treatment. DESIGN: Cross-sectional observational study. SETTING: University medical center and Institute of Nuclear Physics. PATIENTS: Twenty-four patients on CAPD; 14 chronic renal failure (CRF) patients not on dialysis, and 52 healthy controls. MEASUREMENTS: Calcium and Sr content of serum, urine or dialysate effluent, and selected dietary products. RESULTS: Calcium and Sr are absorbed by the intestinal tract of healthy subjects with equal efficiency. Serum Ca levels were considerably lower in CRF patients than in healthy subjects and patients on CAPD (p < 0.001). Serum Sr was significantly higher in both CAPD and CRF patients than in healthy controls (p < 0.001). The Sr/Ca ratio in the sera of the healthy subjects was defined by the preferential excretion of Sr over Ca by the kidney. This preferential excretion was lost during renal failure. During treatment there was a tendency for the uptake of both Ca and Sr to increase. CONCLUSIONS: Strontium is accumulated in the body during renal failure and CAPD cannot restore normal levels. Considering the varying effects of different doses of Sr on bone metabolism experimentally, it would be interesting to determine by further studies the possible significance of the observed Sr accumulation for renal bone disease.
The purpose of this study was to assess the effect of topical application of a sustained-release device in form of a varnish containing strontium chloride on dentinal hypersensitivity. Sixty teeth were selected in ten patients. The teeth were divided in a) varnish application containing strontium chloride, b) varnish application with no active ingredient, c) untreated teeth. Varnish application was carried out by the patients once daily for 30 days. Results show a marked decrease in hypersensitivity to both mechanical (54%) and thermal stimuli (38%) as compared to the placebo and untreated group.
Incorporation of strontium, lead and nickel radioisotopes was studied in mouse calvaria in tissue culture. About 90% of the incorporated strontium and 5-12% of the lead were recovered in the mineral phase of the calvaria (hot acid soluble fraction), whereas the nickel was recovered mainly in the organic phase (hot alkali soluble fraction). Metabolic inhibition enhanced the incorporation, which indicated that the mineral metabolism of the calvaria comprised ionic exchange or secondary mineralization phenomenons independent of the activity of bone cells but, possibly, guided by a metabolically active bone membrane.
Retention of radioactive strontium 85Sr (18,5 kBq i.e. 0.5 microCi i.p.)--concerning the whole body and in distal epiphysis, distal metaphysis and in the thigh bone diaphysis--was followed up in two similar experiments for the period of 5-6 weeks in rats of both sexes and different age (younger category 40-45 days, older category 120-140 days). In both experiments bone retention 85Sr in older female rats is lower than in younger female rats. In male rats similar difference has not been constantly proved. Retention seems to be higher in female rats in comparison with males in the category of young rats. On the contrary in the category of older rats the retention is lower in female rats. In epiphysis and diaphysis of the thigh bone the differences are analogous to whole body differences; 85Sr reacts in the opposite way in distal metaphysis--retention is here extensively higher in older rats than in younger ones. The results obtained confirm the conclusion interesting from the point of view of clinical problem: avidity of the skelet to administered radioactive strontium is in younger female rats higher than in young male rats. However it is severely declining especially in female rats--in the second experiment as far as the level significantly lower than in male rats of the same older age category.
The effect of the topical application of fluoride and strontium on dental enamel has been studied. 30 subjects were split into two groups, all of whom had to have their first superior premolars extracted. One of the two premolars to be extracted was treated with three applications of APF gel in the first group, and with a series of topical applications of SrCl2 at 0.2% and EDTA at 10% in the second group. The results obtained show a significant increase in the concentration of trace elements in enamel of the treated teeth, the increase being of 0.23 and 0.05 mcg/mcm for the fluoride in the most superficial and in the deepest respectively of the observed strata. In the control teeth the average concentrations of fluoride resulted in 0.08 mcg/mcm on the surface and in depth, while the strontium showed an average concentration of 0.03 mcg/mcm. Similar behaviour was observed for the depth of biting resulting in an average of 6.8 mcm in the two groups of treated samples and of 11.4 and 9.7 mcm for the controls, respectively. The results confirm the usefulness of topical treatments and should stimulate further investigations of the problem mainly for the evaluation in the long run of the benefits and the efficacy of treatments integrating the two active principles.
In chronic strontium-90 administration into rats aged 8--10 months osteosarcomas did not develop, while in animals at the age of 3--4 months osteosarcomas incidence was 6.7%. In single injection of the radionuclide in 8--10 months old animals osteosarcomas developed in 2.2% of observations, whereas in 3--4 months old animals--in 45.7%. The most early appearance of osteosarcomas (at the 193d--316th day) was noted in 3--4 months old animals subjected to a single exposure to strontium-90.
Tests conducted on albino rats of the Wistar line demonstrated that introduction of large doses of ergocalciferol (vitamin D2) to animals kept on a strontium-rich diet exhibiting signs of rickets brings about the development in them of specific manifestations of the D-vitamin activity, viz. rising level of calcium, strontium and inorganic phosphorus in the blood serum, lowering of the alkaline phosphatase activity and a greater degree of the soft tissues calcification.
We report measurements of absorbed dose to vertebral metastases in ten patients referred for 89Sr therapy for disseminated prostatic carcinoma. Patients received a tracer dose of 85Sr at the time of 89Sr treatment and metastatic strontium retention was monitored scintigraphically for 6 mo. Metastatic 85Sr activity corrected for tissue attenuation was measured using the conjugate view principle, with special care taken to eliminate errors due to the selection of the metastatic region of interest. Metastatic volume was determined from high resolution CT images, and density inferred from Hounsfield number using the QCT bone mineral calibration of Genant and Cann. The mean absorbed dose was 850 rad/mCi (23 cGy/MBq) with a range from 220-2260 rad/mCi (6 to 61 cGy/MBq). The wide range found was consistent with the variation expected to arise due to differences in strontium renal plasma clearance (range 0.1-11.81/day) and extent of skeletal metastatic disease (varying from two small metastases to a superscan on [99mTc]MDP images) among the patients studied.