The effects of strontium ranelate on the risk of vertebral fracture in women with postmenopausal osteoporosis

BACKGROUND

Osteoporotic structural damage and bone fragility result from reduced bone formation and increased bone resorption. In a phase 2 clinical trial, strontium ranelate, an orally active drug that dissociates bone remodeling by increasing bone formation and decreasing bone resorption, has been shown to reduce the risk of vertebral fractures and to increase bone mineral density.

METHODS

To evaluate the efficacy of strontium ranelate in preventing vertebral fractures in a phase 3 trial, we randomly assigned 1649 postmenopausal women with osteoporosis (low bone mineral density) and at least one vertebral fracture to receive 2 g of oral strontium ranelate per day or placebo for three years. We gave calcium and vitamin D supplements to both groups before and during the study. Vertebral radiographs were obtained annually, and measurements of bone mineral density were performed every six months.

RESULTS

New vertebral fractures occurred in fewer patients in the strontium ranelate group than in the placebo group, with a risk reduction of 49 percent in the first year of treatment and 41 percent during the three-year study period (relative risk, 0.59; 95 percent confidence interval, 0.48 to 0.73). Strontium ranelate increased bone mineral density at month 36 by 14.4 percent at the lumbar spine and 8.3 percent at the femoral neck (P<0.001 for both comparisons). There were no significant differences between the groups in the incidence of serious adverse events.

CONCLUSIONS

Treatment of postmenopausal osteoporosis with strontium ranelate leads to early and sustained reductions in the risk of vertebral fractures.

Strontium increases vertebral bone volume in rats at a low dose that does not induce detectable mineralization defect

Low doses of strontium and fluoride were shown to increase bone formation and trabecular bone density in rodents. To assess whether strontium or fluoride affect the quality of the mineral at doses known to increase bone density, we have determined the effects of low doses of strontium and fluoride on bone formation and bone mineral characteristics in rats. Adult rats were given strontium alone (0.20%), fluoride alone (1 mg/kg per day), or the combined treatment for 8 weeks. Strontium levels in serum and femur were similar in groups treated with strontium alone or in combination, being about 5% of calcium levels. Biochemical and neutron activation analyses in femur showed that calcium and magnesium contents did not differ in the four group of rats, suggesting that strontium was incorporated in the apatite lattice of the bone minerals in the strontium-treated rats. The mineralized bone volume was significantly increased by 17% in the strontium-treated group, by 20% in the fluoride-treated group, and by 19% in rats given with the combined treatment. This was associated with increased osteoid surface, osteoblast surface, and double tetracycline labeled surfaces in the strontium-treated and fluoride-treated groups, showing that the number of bone forming sites was increased. However, the mineral apposition rate, the osteoid thickness, and the mineralization lag time were similar in controls and treated groups, reflecting the lack of deleterious effects of low doses of strontium and fluoride on bone mineralization. The density fractionation analysis measured in the femur also showed that neither strontium, nor fluoride at the low doses used, significantly altered the mineralization profile. The results indicate that treatment with low doses of strontium or fluoride increase the number of bone forming sites and vertebral bone volume in rats, but does not have detectable adverse effects on the mineral profile, bone mineral chemistry or bone matrix mineralization.

Strontium ranelate improves bone strength in ovariectomized rat by positively influencing bone resistance determinants

SUMMARY

Treatment of adult ovariectomized (OVX) rats with strontium ranelate prevented vertebral biomechanics degradation as a result of the prevention of bone loss and micro-architecture deterioration associated to an effect on intrinsic bone material quality. Strontium ranelate influenced the determinants of bone strength by prevention of ovariectomy-induced changes which contribute to explain strontium ranelate antifracture efficacy.

INTRODUCTION

Strontium ranelate effects on the determinants of bone strength in OVX rats were evaluated.

METHODS

Adult female Sprague-Dawley rats were OVX, then treated daily for 52 weeks with 125, 250, or 625 mg strontium ranelate/kg. Bone strength, mass, micro-architecture, turnover, and intrinsic quality were assessed.

RESULTS

Strontium ranelate prevented ovariectomy-induced deterioration in mechanical properties with energy necessary for fracture completely maintained vs. SHAM at 625 mg/kg/day, which corresponds to the clinical dose. This was related to a dose-dependent effect on bone volume, higher trabeculae number, and lower trabecular separation in strontium ranelate vs. OVX. Load and energy required to induce lamella deformation were higher with strontium ranelate than in OVX and in SHAM, indicating that the bone formed with strontium ranelate is able to withstand greater damage before fracture. Bone formation was maintained high or even increased in strontium ranelate as shown by mineralizing surfaces and alkaline phosphatase while strontium ranelate led to reductions in deoxypyridinoline.

CONCLUSION

Strontium ranelate administered at 625 mg/kg/day for 52 weeks prevented OVX-induced biomechanical properties deterioration by influencing the determinants of bone strength: it prevented bone loss and micro-architecture degradation in association with an effect on intrinsic bone quality. These beneficial effects on bone contribute to explain strontium ranelate antifracture efficacy.

Long-term treatment with strontium ranelate increases vertebral bone mass without deleterious effect in mice

It was previously shown that strontium ranelate (SR; S12911-PROTOS, Institut de Recherches Internationales Servier, Courbevoie, France) can modulate bone metabolism in rats and mice. To determine the long-term effects of SR on vertebral bone metabolism in adult mice, the compound or the vehicle was given in the diet to normal male and female mice for 104 weeks at the dose of 200, 600, or 1,800 mg/kg/d corresponding to 0.78, 2.34 or 7.01 mmol Sr(2+)/kg/d. SR dose-dependently increased plasma strontium concentration, as well as exposure to the drug. Histomorphometric analyses of indices of bone volume, bone formation, and resorption were determined in the endosteal vertebral bone. SR significantly increased the trabecular bone volume by 25% and 59% in females treated with SR 600 and 1,800 mg/kg/d, respectively. This was associated with a 27% and 62% increase in mineralized bone volume. Bone volume was also significantly increased by 17% and 38% in male mice treated with SR 200 and 1,800 mg/kg/d, respectively. In parallel, SR increased the osteoblastic surface by 131% in males. In addition to this stimulatory effect on bone formation, a 52% decrease in osteoclastic surface, and a dose-dependent decrease in osteoclastic number (30% to 47%), was observed in female mice. Finally, SR even at the highest dose tested did not alter the osteoid thickness, indicating no deleterious effect on bone mineralization. Altogether, these findings show that SR simultaneously increases bone formation and decreases bone resorption in male or female mice, which results in increased vertebral bone mass in both genders without deleterious effect on bone mineralization.

Evaluation of the use of human hair for biomonitoring the deficiency of essential and exposure to toxic elements

Monitoring the nutritional status of essential elements and assessing exposure of individuals to toxic elements is of great importance for human health. Thus, the appropriate selection and measurement of biomarkers of internal dose is of critical importance. Due to their many advantages, hair samples have been widely used to assess human exposure to different contaminants. However, the validity of this biomarker in evaluating the level of trace elements in the human body is debatable. In the present study, we evaluated the relationship between levels of trace elements in hair and whole blood or plasma in a Brazilian population. Hair, blood and plasma were collected from 280 adult volunteers for metal determination. An ICP-MS was used for sample analysis. Manganese, copper, lead and strontium levels in blood varied from 5.1 to 14.7, from 494.8 to 2383.8, from 5.9 to 330.1 and from 11.6 to 87.3 microg/L, respectively. Corresponding levels in hair varied from 0.05 to 6.71, from 0.02 to 37.59, from 0.02 to 30.63 and from 0.9 to 12.6 microg/g. Trace element levels in plasma varied from 0.07 to 8.62, from 118.2 to 1577.7 and from 2.31 to 34.2 microg/L for Mn, Cu and Sr, respectively. There was a weak correlation (r=0.22, p<0.001) between lead levels in hair and blood. Moreover, copper and strontium levels in blood correlate with those levels in plasma (r=0.64 , p<0.001 for Cu) and (r=0.22, p<0.05 for Sr). However, for Cu, Mn and Sr there was no correlation between levels in hair and blood. Our findings suggest that while the idea of measuring trace elements in hair is attractive, hair is not an appropriate biomarker for evaluating Cu, Mn and Sr deficiency or Pb exposure.

Protein kinase C activates non-capacitative calcium entry in human platelets

1. In many non-excitable cells Ca2+ influx is mainly controlled by the filling state of the intracellular Ca2+ stores. It has been suggested that this store-mediated or capacitative Ca2+ entry is brought about by a physical and reversible coupling of the endoplasmic reticulum with the plasma membrane. Here we provide evidence for an additional, non-capacitative Ca2+ entry mechanism in human platelets. 2. Changes in cytosolic Ca2+ and Sr2+ were measured in human platelets loaded with the fluorescent indicator fura-2. 3. Depletion of the internal Ca2+ stores with thapsigargin plus a low concentration of ionomycin stimulated store-mediated cation entry, as demonstrated upon Ca2+ or Sr2+ addition. Subsequent treatment with thrombin stimulated further divalent cation entry in a concentration-dependent manner. 4. Direct activation of protein kinase C (PKC) by phorbol-12-myristate-13-acetate or 1-oleoyl-2-acetyl-sn-glycerol also stimulated divalent cation entry, without evoking the release of Ca2+ from intracellular stores. Cation entry evoked by thrombin or activators of PKC was abolished by the PKC inhibitor Ro-31-8220. 5. Unlike store-mediated Ca2+ entry, jasplakinolide, which reorganises actin filaments into a tight cortical layer adjacent to the plasma membrane, did not inhibit divalent cation influx evoked by thrombin when applied after Ca2+ store depletion, or by activators of PKC. Thrombin also activated Ca2+ entry in platelets in which the release from intracellular stores and store-mediated Ca2+ entry were blocked by xestospongin C. 6. These results indicate that the non-capacitative divalent cation entry pathway is regulated independently of store-mediated entry and does not require coupling of the endoplasmic reticulum and the plasma membrane. These results support the existence of a mechanism for receptor-evoked Ca2+ entry in human platelets that is independent of Ca2+ store depletion. This Ca2+ entry mechanism may be activated by occupation of G-protein-coupled receptors, which activate PKC, or by direct activation of PKC, thus generating non-capacitative Ca2+ entry alongside that evoked following the release of Ca2+ from the intracellular stores.

Increased serum cadmium and strontium levels in young smokers: effects on arterial endothelial cell gene transcription

OBJECTIVE

Metal constituents of tobacco have long been suspected to contribute to cardiovascular diseases. In this study, we determined the serum concentrations of aluminum, cadmium (Cd), cobalt, copper, iron, manganese, nickel, lead, strontium (Sr), and zinc of young nonsmokers, passive smokers, and smokers.

METHODS AND RESULTS

Cd and Sr were found to be significantly increased in smokers compared with nonsmokers. The effects of these metals on primary arterial endothelial cells were then assessed using microarray technology and real-time polymerase chain reaction (RT-PCR). The data showed that Sr does not interfere with endothelial cell transcription. In contrast, the effects of Cd in amounts delivered to the human body by smoking were dramatic.

CONCLUSIONS

Arterial endothelial cells responded to Cd exposure by massively upregulating metal and oxidant defense genes (metallothioneins) and by downregulating a number of transcription factors. In addition, the mRNA of the intermediate filament protein vimentin, crucial for the maintenance of cellular shape, was reduced. Surprisingly, a number of pro-inflammatory genes were downregulated in response to Cd. The present data suggest that by delivering Cd to the human body, smoking deregulates transcription, exerts stress, and damages the structure of the vascular endothelium; furthermore, in contrast to the effects of cigarette smoke as a whole, Cd seems to possess anti-inflammatory properties.

Strontium ranelate does not stimulate bone formation in ovariectomized rats

INTRODUCTION

Strontium ranelate (SrR) is suggested to function as a dual-acting agent in the treatment of postmenopausal osteoporosis with anti-resorptive and anabolic skeletal benefits. We evaluated the effects of SrR on the skeleton in ovariectomized (OVX) rats and evaluated the influence of dietary calcium.

METHODS

Three-month old virgin female rats underwent ovariectomy (OVX, n = 50) or SHAM surgery (SHAM, n = 10). Four weeks post-surgery, rats were treated daily by oral gavage with distilled water (10 ml/kg/day) or SrR (25 or 150 mg/kg/day) for 90 days. Separate groups of animals for each dose of SrR were fed a low (0.1%) or normal (1.19%) calcium (Ca) diet. Static and dynamic histomorphometry, DXA, mu-CT, mechanical testing, and serum and skeletal concentrations of strontium were assessed.

RESULTS

SrR at doses of 25 and 150 mg/kg/day did not increase bone formation on trabecular or periosteal bone surfaces, and failed to inhibit bone resorption of trabecular bone regardless of Ca intake. There were no improvements in bone mass, volume or strength with either dose of SrR given normal Ca.

CONCLUSION

These findings demonstrate that SrR at dosages of 25 and 150 mg/kg/day did not stimulate an anabolic bone response, and failed to improve the bone biomechanical properties of OVX rats.

Trace elements in obese Turkish children

The quality of the diet of obese children is poor. Eating habits may alter micronutrient status in obese patients. In this study, we determined the serum levels of selenium, zinc, vanadium, molybdenum, iron, copper, beryllium, boron, chromium, manganese, cobalt, silver, barium, aluminum, nickel, cadmium, mercury, and lead in obese Turkish children. Thirty-four obese and 33 healthy control subjects were enrolled in the study. Serum vanadium and cobalt levels of obese children were significantly lower than those of the control group (0.244 ± 0.0179 vs. 0.261 ± 0.012 μg/l, p < 0.001, and 0.14 ± 0.13 vs. 0.24 ± 0.15 μg/l, p = 0.011, respectively). There was no significant difference between groups regarding the other serum trace element levels. In conclusion, there may be alterations in the serum levels of trace elements in obese children and these alterations may have a role in the pathogenesis of obesity.

Calcium absorption and calcium-binding protein synthesis: solanum malacoxylon reverses strontium inhibition

The ingestion of diets containing high concentrations of stable strontium inhibits calcium absorption and intestinal calcium-binding protein synthesis and, as shown by others, does so by inhibiting the conversion of 25-hydroxycholecalciferol to 1,25-dihydroxycholecalciferol, the active form of vitamin D. The addition of the South American plant Solanum malacoxylon to strontium-containing diets counteracts the inhibitory action of dietary strontium, thereby indicating that the plant contains a factor which can mimic the action of 1,25-dihydroxycholecalciferol and representing the first such factor identified in a botanical source.

Mechanism of the hypocalcemic effect of mithramycin

Mithramycin is effective in the treatment of hypercalcemia. The mechanism of its hypocalcemic effect was studied in six patients with hypercalcemia by serum 85Sr or 45Ca kinetic techniques. Mithramycin was given at two dosage levels (25 or 50 microgram/kg iv). Mithramycin at the low dosage had little effect on the rate of bone accretion. However, at both dosage levels, mithramycin caused an upward shift of the slope of the specific activity curve, indicating an inhibitory effect on bone resorption. This effect started 6-12 h after a 25-microgram/kg dose of mithramycin and lasted from 4-6 days. It appears that mithramycin has a preferential effect on bone resorption.

Elemental contents in serum of pregnant women with gestational diabetes mellitus

Diabetes mellitus is characterized by hyperglycemia and is closely related to trace elements. Quite a few pregnant women suffer from impaired glucose tolerance (IGT) or gestational diabetes mellitus (GDM). Investigation of the changes of elemental contents in serum of the pregnant women with IGT and GDM is significant in the etiological research and cure of the diseases. In the present work, the elements Cu, Zn, Ca, Sr, Mg, P, Fe, and Al in the serum of pregnant women were determined. The elemental contents in different experimental groups were compared. Also, the correlation between elemental contents and gestational period was observed. The results showed that compared with normal pregnant women, the Cu contents in serum of pregnant women with GDM increased, but Zn contents had a decreasing trend. In addition, for all pregnant women, the Ca contents in serum had an obvious inverse correlation with gestational period.

Study of the diagnostic value of strontium, chloride, haemoglobin and diatoms in immersion cases

Tests of haemoglobin (Hb), strontium (Sr) and chloride (Cl), as well as diatoms, toxicological and pathological studies were performed in biological samples from 133 immersion fatalities occurred since 1991 to 1996 in central and northern Spain. Hb, Sr, and Cl where analyzed in blood samples where increasing decomposition could be demonstrated in most of the cases. The samples were frequently accompanied with well documented forensic reports, including autopsies findings and other circumstances of the death. The goal of our study is to evaluate the difference of blood Sr concentration between the left and right side of the heart (LVSr-RVSr) as a marker of drowning. For this purpose, the cases investigated were classified in 'typical drowning' (TD) cases and 'atypical drowning' (AD) cases. This last group was used as a control. The comparison of the LVSr-RVSr between TD and AD cases was highly significant (P = 0.0002) in blood specimens extracted from cases occurred in putative drowning media where Sr concentration was higher than 800 micrograms/l. No significant differences were found comparing neither Cl nor Hb biventricular concentrations between TD and AD cases in blood samples extracted from bodies found in both fresh and seawater.

Diagnosing death by drowning in fresh water using blood strontium as an indicator

The interpretation of the level of strontium (Sr) in blood has been demonstrated to be useful in the diagnosis of death by drowning occurred in sea water, but its use in fresh water drownings is not so evident because of the low Sr concentration present in most of fresh water media. In this paper, we show a survey of the results obtained in the casework analysis of Sr in ventricular blood used in the diagnosis of drowning in 144 bodies found immersed in fresh water over a period of 10 years. Thirty-two percent of the immersion cases examined could be diagnosed as drownings with a reasonable degree of confidence. It is thought that this percentage of positive diagnoses could be largely improved in the case of blood samples taken a few hours after death.

Time-evolution and reversibility of strontium-induced osteomalacia in chronic renal failure rats

BACKGROUND

Patients with impaired renal function can accumulate strontium in the bone, which has been associated with the development of osteomalacia. A causal role for strontium in the development of the disease was presented in chronic renal failure (CRF) rats. Strontium-ranelate has been put forward as a therapeutic agent in the treatment of osteoporosis. Since the target population for strontium treatment consists mainly in postmenopausal osteoporotic women, who may have a reduced renal function, the risk for osteomalacia should be considered.

METHODS

To determine the time evolution and reversibility of the strontium-induced mineralization defect, CRF rats were loaded with strontium (2 g/L) (+/- 200 mg/kg/day) during 2, 6, and 12 weeks, followed by a washout period of 0, 2, 4, or 8 weeks.

RESULTS

Histologic examination of the bone of the animals treated with strontium revealed signs of osteomalacia already after 2 weeks. Animals that received strontium during 6 and 12 weeks had a significantly higher osteoid perimeter, area and thickness as compared to CRF controls. After 12 weeks, the mineralization was significantly affected, as evidenced by a lower double-labeled surface, mineral apposition and bone formation rate in combination with an increased osteoid maturation time and mineralization lag time. The osteoblast perimeter was significantly lower in the strontium-treated animals. After the washout periods, these effects were reversed and the bone lesions evolved to the values of CRF controls. This went along with an 18% reduction of the bone strontium content. A significant rise in serum alkaline phosphatase (ALP) activity was apparent in the strontium-treated animals as compared to CRF controls. This was not only due to higher levels of the bone ALP but also to those of the liver and the intestinal isoenzymes. Serum parathyroid hormone (PTH) levels decreased during strontium treatment. After cessation of the treatment, the serum ALP activity and PTH concentration reversed to control levels.

CONCLUSION

In this study evidence is provided for the rapid development of a mineralization defect in strontium-loaded CRF rats, accompanied by a reduced osteoblast number, reduced PTH synthesis or secretion, and increased serum ALP levels. These effects can be rapidly reversed after withdrawal of the compound.

Determination of strontium in human whole blood by ICP-AES

The determination of strontium in human blood samples by ICP-AES is described. For the analysis no chemical separations were required after microwave destruction. A mean value of 11.4 +/- 0.83 micrograms/l is found for normal whole blood. The limit of detection of the method is 0.3 microgram/l. As a possible application the enhancement of the strontium level in blood of human beings who died from drowning is examined.

Increased serum strontium levels in dialysis patients: an epidemiological survey

BACKGROUND

We previously reported on increased bone strontium levels in dialysis patients with osteomalacia versus those presenting other types of renal osteodystrophy. A causal role of strontium in the development of osteomalacia was established in a chronic renal failure rat model.

METHODS

To further elucidate the latter issue and to find out whether dialysis patients from particular centers/countries are at an increased risk for strontium accumulation, a worldwide multicenter study was established. In total, 834 patients from 34 dialysis centers in 23 countries were included. In each of the patients, a serum sample was taken for strontium determination, and water and dialysate samples were taken at the various steps of the water purification process. For each patient clinical data and for each center dialysis modalities were recorded.

RESULTS

Strontium levels in serum of dialysis patients showed major differences between the various centers, ranging from mean values of 25 +/- 8 microgram/liter in the center with the lowest level up to 466 +/- 90 microgram/liter in the center with the highest concentration. It is of interest that these high levels were mainly found in developing countries. Furthermore, our data point toward a role of the final dialysate in the accumulation of the element, as indicated by the strong correlation (r = 0.74, P < 0.001) between mean serum and dialysate strontium levels. As the high tap water concentration of strontium was adequately reduced during the water purification process, contamination of the final dialysis fluid occurred by the addition of concentrates contaminated with strontium. Besides the dialysate, other factors, such as duration of dialysis, vitamin D supplements, or types of phosphate binders, played a less important role in the accumulation of the element.

CONCLUSIONS

Data of this multicenter study indicate patients of particular dialysis centers to be at an increased risk for strontium accumulation, the clinical consequence of which is under current investigation.

Biventricular measurement of blood strontium in real cases of drowning

A simple method for blood strontium determination by spetrophotometry atomic absorption with Zeeman correction is proposed. This method is applied to real cases of death by drowning, where the difference in blood strontium concentration between the left and the right side of the heart could contribute, together with other data, to the investigation of causes of death in cases of drowning in salt water. The differences obtained in blood strontium concentrations between the left and the right side of the heart in cases of supposed 'typical drowning' in sea water were always > 75 micrograms Sr/l, compared to < 20 micrograms Sr/l found in two supposed cases of 'atypical drowning'.

Blood strontium concentration related to the length of the agonal period in seawater drowning cases

The levels of ventricular blood strontium (Sr) from 70 seawater drowning victims were compared with their diagnosis of drowning based mainly on certain criteria selected from their autopsy report. From this comparison, intervals of either the difference of Sr concentration between the left and the right ventricle blood (LVSr-RVSr) or the Sr concentration in the left ventricle blood (LVSr), appear to be related to different time-lapses of the agonal period of drowning. In the aim to diagnose drownings, intervals of both LVSr-RVSr and LVSr were proposed to characterize three different agonal periods in seawater drowning cases: instantaneous death (ID), fast vital-submersion drowning (FVSD) and common vital-submersion drowning (CVSD).

Strontium and oxidative stress in normal pregnancy

BACKGROUND

Pregnancy brings about metabolic and oxidative changes that involve various trace elements and oxidative stress. Strontium (Sr) is a trace element scarcely studied in this context, although it has been suggested that it may play a role in the pathophysiology of preeclampsia. The main aim of this study was to evaluate Sr concentrations and oxidative status in normal pregnancy.

METHODS

The study population included non-pregnant women (n=31), healthy pregnant women in the first (n=50), second (n=51) and third (n=53) trimesters of gestation, and women in postpartum period (n=31). Additionally, samples from another twenty pregnant women were obtained in the three trimesters. Strontium, copper, selenium and zinc were measured by inductively coupled plasma-mass spectrometry. Calcium (Ca), uric acid (UA), lipid peroxidation and total antioxidant activity (TAA) were measured by spectrophotometric assays.

RESULTS

Strontium remained unchanged until the third trimester of pregnancy, in which significantly higher levels were found (p=0.001). The other elements showed diverse trends during pregnancy. Uric acid levels were significantly different in all groups (p<0.001), increasing gradually as the pregnancy progresses. In serial samples, there was a statistically significant positive correlation between Sr and gestational week of sampling (r=0.31, p=0.01), UA (r=0.40, p=0.001) and lipid peroxidation/TAA ratio (r=0.38, p=0.0002). Additionally, Sr correlated negatively with TAA (r=-0.40, p=0.0001).

CONCLUSION

Strontium seems to play a physiological role in the oxidative status of the human organism. Further studies involving Sr and pathologies of pregnancy are warranted.

Strontium-89 chloride (Metastron) for palliative treatment of bony metastases. The University of Minnesota experience

Strontium-89 chloride (Metastron) is an FDA-approved treatment for palliation of cancer pain. We evaluated blood count changes and pain relief in 28 patients with widespread painful bony metastasis treated with strontium-89 at the University of Minnesota Hospital and Clinics. Eighteen patients had prostate cancer (all hormone-refractory cancer), seven patients had breast cancer, and three patients had lung cancer, all previously treated with either radiation, chemotherapy, or a combination of the two. Serial blood counts were performed weekly up to 8 weeks and at 12 weeks after administering Metastron. Pain scale and blood values were monitored simultaneously. The mean baselines of hemoglobin (Hgb), white blood count (WBC), and platelets (Plts) were 11.4, 5900, and 258,000, respectively. The mean dose of Metastron was 3 mCi (range 2.2-4.4). The median time (range) to nadir was about 6 weeks. The percentage reductions relative to baseline were 32% (range 0-72%) for WBC; 14% (range 0-50%) for Hgb; 15% (range 0-47%) for the red blood cell (RBC) count; and 40% (range 0-85%)for Plts. We did not find a close relationship among the baseline blood count, reduction of subsequent blood counts, or previously irradiated active bone marrow volume. The median time of survival was 23 weeks (range 2-66 weeks). At 12 weeks, 29% of patients had moderate to dramatic improvement of pain, 32% had some relief of pain, and 50% had no improvement in pain. Thirty-two percent of the treated patients required additional palliative external beam radiation to their bony lesions within the study period. Our results show that Metastron for palliation for bony metastases should be used with caution because of moderate to severe bone marrow toxicity, especially in platelets, associated with its use. Careful evaluation of patients given Metastron is needed to assess accurately its full benefit.

Increase in blood plasma levels of boron and strontium in hemodialyzed patients

Boron and strontium concentrations in blood plasma of controls and hemodialyzed patients from two Centers were determined by inductively coupled plasma emission spectrometry. Boron concentrations in blood plasma were respectively, in controls 2.6 +/- 0.9 mumol/l and in hemodialyzed patients 16.1 +/- 5.6 mumol/l before the dialysis session and 9.5 +/- 3.2 mumol/l at the end. The decrease in blood plasma during the dialysis was concomitant with an increase in the dialysis fluid (1.2 +/- 0.7 mumol/l at the beginning and 4.6 +/- 1.8 mumol/l at the end). Strontium concentrations in blood plasma were respectively, in controls 0.22 +/- 0.06 mumol/l and in hemodialyzed patients 0.62 +/- 0.24 mumol/l before the dialysis session and 0.64 +/- 0.14 mumol/l at the end. The mean concentration of strontium in the dialysis fluid was the same before (0.49 +/- 0.11 mumol/l) and after the dialysis session (0.49 +/- 0.10 mumol/l), but a transfer between plasma and dialysis fluid was shown by individual changes. Some considerations about these results are put forward but their possible clinical consequences are not yet known.