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PubMed1970

Strontium-90: effects of chronic ingestion on farrowing performance of miniature swine.

In experiments involving the ingestion of strontium-90 by nearly 800 female miniature swine and extending over three generations, no significant differences in litter size, percentage of stillborn, or birth weight were observed between controls and animals ingesting up to 625 microcuries of strontium-90 per day. At 625 microcuries per day, these animals were ingesting more than a million times the peak value of strontium-90 ever reported in the American diet. Animals on 3100 microcuries per day did not survive the gestation period. From these studies, it is evident that feeding levels of strontium-90 high enough to affect fetal or neonatal mortality in this species will not permit maternal survival long enough for the bearing of young.

Animals↗
PubMed1998

Correlation between Octopus perimetry and fluorescein angiography after strontium-90 plaque brachytherapy for subfoveal exudative age related macular degeneration.

AIM: To evaluate the correlation between the central visual field and changes in fluorescein angiography and fundus photography in patients treated with strontium plaque radiotherapy for subfoveal exudative age related macular degeneration (AMD). METHODS: Octopus program 34 automated static perimetry, fluorescein angiography, and colour fundus photography were performed on 19 patients at baseline and at 12 months after strontium-90 plaque therapy. A schematic picture outlining the areas of hyperfluorescent neovascular membranes and subretinal blood was drawn of a projected 30 degrees fundus fluorescein angiogram. This drawing was superimposed on the size adjusted Octopus visual field. The changes in retinal sensitivity were calculated and related to angiographic changes. RESULTS: Three of the 19 patients had a reliability factor (RF) > 15% and were excluded from further analysis. In the remaining 16 patients the mean defect (MD) and loss variance (LV) values remained unchanged in patients showing regression of the choroidal neovascular membrane (CNVM) to irradiation at 12 months. MD was 7.7 (SD 1.7) at baseline and 7.6 (1.9) at 12 months (p = 0.86), and LV was 32.6 (13.9) at baseline and 32.4 (15.7) at 12 months (p = 0.94). However, in patients with progression of the CNVM at 12 months, both the MD and LV increased significantly during the 12 month follow up (MD from 7.3 (2.9) to 13.1 (3.6) (p = 0.05) and LV from 31.0 (22.9) to 71.8 (24.1) (p = 0.017)). When comparing the mean retinal sensitivity in the area of the primary CNVM (including classic, occult, and haemorrhagic components), the results were analogous: in patients with a regression of the CNVM after irradiation the mean sensitivity remained almost unchanged. It was 10.3 (6.4) dB at baseline and 9.4 (7.3) dB at 12 months (p = 0.58). In five out of 11 patients (45%) with regression of the CNVM, the mean retinal sensitivity even improved by 2.0-5.0 dB in the area of the original lesion during follow up. Instead, in patients showing progression of the CNVM at 12 months, there was a significant loss in mean retinal sensitivity--from 9.9 (4.6) dB at baseline to 1.0 (1.1) dB at 12 months (p = 0.019). The mean retinal sensitivity in the area of the irradiated but clinically normal retina during follow up was not significantly altered (21.5 dB at baseline, 19.7 dB at 12 months (p = 0.10)). CONCLUSIONS: Regression of subfoveal choroidal membranes in AMD after focal strontium irradiation is connected with stabilisation or even improvement of retinal sensitivity in central visual field measured by automated perimetry. Strontium plaque irradiation does not change the sensitivity in clinically normal paramacular retina during a 12 month follow up.

Aged↗
PubMed1977

Kinetic analysis of 25-hydroxyvitamin D3 metabolism in strontium-induced rickets in the chick.

Kinetic data analysis was used to derive a six-compartment computer model which describes the in vivo [3H]25-hydroxyvitamin D3 ([3H]25-OHD3) metabolism in control and strontium rachitic chicks. Plasma concentrations of 25-OHD3 (13 pmol/ml) and 25, 25-dihydroxyvitamin D3 (0.9 pmol/ml) were 18 and 125% greater than controls, respectively, whereas the corresponding level for 1alpha,25-dihydroxyvitamin D3 (0.3 pmol/ml) was only 30% of control. Plasma disappearance of 25-HOD3 was fitted using a two-compartment model in which the metabolite extrapolated half-life was nearly twice as large for strontium rachitic chicks (71 compared to 41 h). Intestinal sequestration of 1alpha,25-dihydroxyvitamin D3 was assumed to be irreversible and was fitted by a single exponential term in which metabolite uptake rate and tissue concentration in strontium rickets was suppressed to 20 and 10% of control, respectively. In contrast, uptake of 25-OHD3 by the intestine was observed to occur by a reversible process in which metabolite concentration was 45% greater in the strontium rachitic compared to control group. The developed compartment model accepts time-dependent control or perturbed metabolite data for the plasma and (or) intestinal pools and provides quantitative values for metabolite pool size, flux rate, and turnover time.

Animals↗
PubMed1977

Diffusion of strontium from desensitizing agents into human dentin as determined by energy-dispersive analysis.

Strontium-containing desensitizing agents were applied to one set of tooth surfaces and were burnished onto another set of diametric surfaces. Concentration of strontium at dentin depth was determined by X-radiation dispersive analysis. Burnishing produced deeper strontium penetration. Fick's Second Law provided an estimate of relative effective time for equal strontium distributions by the two methods.

Dentin↗
PubMed1985

The relation between caries prevalence and strontium concentrations in drinking water, plaque, and surface enamel.

Samples of plaque and surface enamel were collected from 80 boys aged 14 years living in five communities in Ohio (USA). Mean (+/- SE) strontium concentrations in plaque were 1.43 +/- 0.18 micrograms/g (wet) and 12.34 +/- 1.63 micrograms/g (dry). For surface enamel, the mean concentration was 421 +/- 31 micrograms Sr/g. Concentrations of strontium in both plaque and enamel were significantly related to strontium levels in the drinking water. Caries prevalence as DMFS was inversely related to strontium levels in water, plaque, and enamel.

Adolescent↗
PubMed1978

Single-skinned human muscle fibers: activation by calcium and strontium.

Single-skinned fibers were prepared from human skeletal muscle. Tension generation was measured in solutions containing different amounts of free calcium or strontium ion. Fibers were classified into two types, on the basis of distinct differences in their regulation by strontium. One group developed maximal tension in 3 x 10-5 M free strontium, whereas the other developed minimal or no tension in the same concentration of strontium. It seemed most probable that the former represented type 1 (slow twitch) fiber and the latter type 2 (fast twitch) fiber because of similar patterns observed in guinea pig soleus and extensor digitorum longus muscle fibers.

Calcium↗
PubMed2004

Noninvasive measurement of bone strontium.

The strontium content of bone has hitherto been impossible to measure noninvasively. A novel dual-photon absorptiometry (DPA) method was developed. 241Am (59.5 keV) and 133Ba (356 keV) were used as radiation sources. The linearity of the DPA method was studied in monkey bones ex vivo after treatment over 52 wk with strontium ranelate. The bone strontium expressed in terms of the percentage molar ratio SrHA/(SrHA + CaHA) x 100%, where HA denotes hydroxyapatite, was measured (1) by the DPA method and (2) by inductively coupled plasma-atomic emission spectrophotometry at the same distal site of the femur. The results correlated significantly: y = 0.33%Sr + 1.086x; r = 0.976; standard error of the estimate (SEE) = 0.57%Sr. In order to measure the accuracy error of Sr%, 30 normal volunteers were measured. Their mean values did not differ significantly from zero and the SD was 0.5%. The radiation dose was small, the equivalent whole-body dose to human subjects being 0.005 micro Sv. This novel DPA method is likely to be successful for bone strontium measurement in humans.

Absorptiometry, Photon↗
PubMed2003

Evaluation of age and gender dependences of the rate of strontium elimination 25-45 years after intake: analysis of data from residents living along the Techa river.

The Mayak Production Association released large amounts of 90Sr into the Techa River with peak amounts in 1950-1951. Residents near the Techa River ingested an average of approximately 3,000 kBq of 90Sr. The affected people have been followed by scientists at the Urals Research Center for Radiation Medicine. The whole-body content of 90Sr of approximately 15,000 individuals has been measured over a period of 24 years (1974-1997) using a special whole-body counter. This report evaluates the gender and age dependences of individual rates of strontium elimination. Data on persons who had been measured 12 or more times were selected for study. There were 108 men and 81 women older than 30 years who met this criterion. Individual measurement results were fitted to an exponential function and grouped mean averages of the rate of strontium elimination as a function of age for each sex were derived. For men, a significant increase (from 2.8% year(-1) to 3.2% year(-1)) in the rate of strontium elimination after age 55 years is seen. For women, the increase in the rate of elimination was significant at age 45 and reached 5.8% year(-1) after the age of 60. The results may be used to develop a gender- and age-dependent model of strontium metabolism.

Adult↗
PubMed1977

Strontium-87m lung scans in pulmonary aspergillosis.

Experimental observations have indicated that radioactive strontium localizes in lesions infected with Aspergillus species. Preliminary clinical studies have recommended use of strontium lung scanning to evaluate patients thought to have pulmonary manifestations of aspergillosis. In view of the difficulty in accurately interpreting the clinical significance of recovery of Aspergillus species from sputum of patients with pulmonary disorders as well as the varied clinical presentations of pulmonary aspergillosis, we have attempted to confirm these reports. Ten patients with proven pulmonary aspergillosis and five selected control subjects without aspergillosis but with other pulmonary disorders were scanned after the injection of 2-3 mCi 87mSr citrate. The strontium lung scan correlated with the chest radiograph in four of 10 patients with aspergillosis; false positive scans were found in three of five patients with other pulmonary disorders. We conclude that strontium lung scans at present have no role in the diagnostic evaluation of patients suspected of clinically significant infections with aspergillus.

Adult↗
PubMed2006

Evaluation of strontium 90 irradiation in treatment of cutaneous mast cell tumors in cats: 35 cases (1992-2002).

OBJECTIVE: To determine the efficacy of strontium 90 beta irradiation in the management of cutaneous mast cell tumors (CMCTs) in cats. STUDY DESIGN: Retrospective case series. ANIMALS: 35 client-owned cats with CMCTs. PROCEDURE: Medical records of cats with CMCTs in which tumors were radiated by use of a strontium 90 ophthalmic applicator from 1992 to 2002 were reviewed. Cats were included if CMCT was diagnosed, there were no other sites of MCT involvement at the time of treatment, and records contained adequate follow-up information to permit retrospective assessment of local tumor control. RESULTS: 54 tumors in 35 cats were treated with a median dose of 135 Gy of strontium 90 beta irradiation, resulting in local tumor control in 53 of 54 (98%) tumors with a median follow-up time of 783 days after treatment. Median survival time was 1,075 days. Adverse effects of treatment appeared to be infrequent and of mild severity. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that strontium 90 beta irradiation resulted in long-term tumor control and should be considered an effective alternative to surgical resection in management of CMCTs in cats.

Animals↗
PubMed1997

[The effects of strontium in drinking water on growth and development of rat bone].

Effects of strontium at a high level in drinking water on growth and development of rat bone were studied. The results showed that Sr2+ concentration from 5 to 500 mg/L in drinking water could increase the contents of strontium in blood serum, urine, femur, mixilla and tooth in Wistar rats exposed to Sr2+ for 12 weeks with an obvious dose-response relationship. In addition, strontium at over 50 mg/L could decrease the contents of calcium in bone, increase the contents of calcium in tooth and bone density, and decrease the levels of calcium in blood serum except female rats at the 12th week. Effects of Sr2+ on body weight, body length, AKP activity of serum, calcium content of urine and breaking load of bended femur for rats were not found. However, there are differences in the effects of strontium on growth and development of bone between male and female rats. At the 12th week the content of calcium in blood serum decreased in male rats but increased in female rats in exposed groups. At the 4th and 8th weeks, urine Hop/Cr in male rats increased but it remained normal level in female rats. Sr2+ increased the bone density of mixilla in male rats but it did not increase that of femur in female rats. It is suggested that such changes may be a result of the differences in endocritic regulation and metabolic process between two sexes.

Animals↗
PubMed2001

[Cytotoxicity of the strontium-substituted hydroxyapatite evaluated by MTT colorimetry].

This study was conducted to evaluate the cytotoxicity of strontium-substituted hydroxyapatite by methyl thiazolyl tetrazolium (MTT) colorimetry. We used the MTT method to assay the cytotoxicity of the strontium-substituted hydroxyapatite containing different strontium concentrations (1%, 5%, 10%, 100% Sr2+) and the pure hydroxyapatite. The results showed that the cytotoxicity scores of the different materials were grade 0 or grade 1. These led us to the conclusion that strontium-substituted hydroxyapatite has good biocompatibility.

Animals↗
PubMed1999

[Effects of strontium in drinking water on the growth of school-age children].

An epidemiological study on the effect of strontium in drinking water on body shape development, bone age, prevalence of caries and dental fluorosis was carried out. The results show: there is a certain promotion on the development of bone age of school-age children, especially of girls, and there is no obvious impact on body shape developing when the concentration of strontium in drinking water is only 10 mg/L. The correlation between strontium in drinking water and the prevalence of caries in children could not get a conclusive evidence in this paper. A further epidemiological investigation is necessary if the role of strontium against caries should be proved.

Adolescent↗
PubMed1992

Use of oral stable strontium to provide an index of intestinal calcium absorption in chronic ambulatory peritoneal dialysis patients.

Recent interest in the role of oral calcium carbonate and low calcium dialysate has emphasised the need for a simple, safe and inexpensive test of intestinal calcium absorption. The stable, non-radioactive, strontium absorption test fits these requirements. Stable strontium and calcium-45 were administered simultaneously to 19 fasting CAPD patients and their serum levels were subsequently measured. There was a close correlation between the absorption of calcium and strontium at both 60 and 120 min post-ingestion. The two markers resulted in the same classification of patients as normal or malabsorbers in 18 of 19 cases (95%), suggesting that strontium could be substituted for calcium-45 in a 60-min test of absorption enabling safe, simple and repeated measurements in renal failure patients.

Administration, Oral↗
PubMed2005

Effects of calcium, strontium, and barium on isolated phrenic nerve-diaphragm preparation of rat and their interactions with diltiazem and nifedipine.

Calcium (Ca2+), strontium (Sr2+), and barium (Ba2+) are expected to exert similar chemical and pharmacological effects. The effects of barium, strontium and calcium were studied on the contractions of rat phrenic nerve-diaphragm preparations, following electrical stimulation and their interactions with nifedipine (nif) and diltiazem (DZM) were also studied. Low doses of strontium chloride (SrCl2), barium chloride (BaCl2) and calcium chloride (CaCl2) were able to increase the force of contraction of the rat diaphragm when actively stimulated. Diltiazem inhibited the stimulant effects of Sr2+, Ba2+, and Ca2+. On the other hand, nifedipine blocked the effects of Sr2+ and Ca2+ but potentiated the effects of Ba2+. Strontium, barium, and calcium restored the contractility of the muscle following electrical stimulation when the tissue was in biological fluid absolutely depleted of calcium. These findings suggest that Sr2+ and Ba2+ may be able to substitute Ca2+ in the rat diaphragm for its contractions and nifedipine and diltiazem may follow different mechanisms of actions or channels in their blocking effects.

Animals↗
PubMed1990

[Effects of strontium on incisor and femurs in rats under drinking condition at constant concentrations of fluoride].

Thirty 28-day-old male Wistar rats were randomly divided into 5 experimental groups of 6 animals, and fed low-fluoride diet (0.07 ppm F) and drinking water containing fluoride at constant concentration (20 ppm F) ad libitum for 49 days in combination with strontium chloride added to provide 0, 5, 10, 20, 40 ppm Sr. Enamel mottling was observed through over-all experimental period, and at an end of the experiment, all animals were sacrificed. There was no significant difference in weight gain among groups. Enamel mottling of mandibular incisors in Sr groups appeared at 7th day (cumulated fluoride ingested: under 3.0mg), while mottling in control group (0 ppm Sr and 20 ppm F) appeared at 14th day (cumulated fluoride ingested: ca. 6.6 mg). However, severity of mottling was higher in low-strontium group (5 and 10 ppm Sr) than in high-strontium groups (20 and 40 ppm Sr). Data of contents of Sr, F, Ca and P in incisors and femurs obtained through chemical analysis suggested that an exchange of Sr and Ca would take place in apatite and that the exchange reaction of F- and OH- could be urged by Sr. Further, data of serum F level demonstrated that the fluoride retention in serum could be urged by lower level of strontium rather than higher one.

Animals↗
PubMed1989

[Strontium content in hard tissues of milk teeth with and without caries].

By the method of atomic absorption flame spectrophotometry the strontium level was determined in the hard tissues of milk teeth with and without caries. The studied material comprised 163 milk teeth, including 81 with caries. All teeth were obtained from children of either sex living in Lublin. The material was divided into three age groups: up to 6 years, 6-10 years, and over 10 years. The obtained results were subjected to statistical analysis using an IMP85 m computer. It was found age and sex had no significant effect on the strontium level in the hard tissues of healthy milk teeth. However, a significant correlation was observed between strontium level and caries presence. Milk teeth with caries contained less strontium than carietic teeth.

Child↗
PubMed1982

Strontium in Finnish foods.

The strontium content of Finnish foods was analyzed and the average daily intake of strontium estimated according to national food consumption statistics. The average intake was 1.9 mg of Sr/d/person, which is well within the range of intakes found in other industrialized countries. The most important sources were dairy products (35%), and vegetables and fruits (32%). The strontium contents of foods showed a highly significant correlation with their calcium contents. No special problem was evident in dietary strontium in Finland.

Animals↗