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PubMed1999

Strontium and samarium therapy for bone metastases from prostate carcinoma.

A review was performed of all patients who received strontium-89 chloride or samarium-153 ethylenediamine-tetramethylenephosphonate for prostate cancer metastatic to bone at the Royal Brisbane Hospital between 1992 and 1997. There were 57 patients, 38 treated with strontium-89 and 19 with samarium-153. Forty patients had radionuclide therapy alone, and 28/40 (or 70%) responded in terms of experiencing a beneficial effect on pain. In the other 17 patients, the effect of the radionuclide on pain could not be assessed because they received external beam radiotherapy concomitant with a therapeutic radionuclide. There was no difference in response rates between the samarium and strontium groups as measured by the effect on pain or in the time to progression. The median time to progression for all patients was 2-3 months. The present study confirms that following administration of a therapeutic radionuclide, a high proportion of patients experienced improvement of pain, but the time to progression is not long, so that the overall degree of benefit is modest.

Aged↗
PubMed2005

Low toxicity and efficacy of (153)samarium-EDTMP and melphalan as a conditioning regimen for secondary acute myelogenous leukemia.

We report the case of a 15-yr-old girl who developed secondary acute myelogenous leukemia (AML) 4 yr after completion of therapy for metastatic Ewing sarcoma (primary right acetabulum with metastatic disease to the lungs). Peripheral blood stem cells were collected after the second cycle of chemotherapy with the plan for future consolidation with high-dose chemotherapy and autologous stem cell rescue; however, because of the patient's excellent response to chemotherapy and surgery, therapy was completed without the need for high-dose chemotherapy. No human leukocyte antigen (HLA)-matched related donor was available for a bone marrow transplant. Because of previous lung radiation, high-dose samarium [30 mCi/kg of samarium-153 ethylenediaminetetramethylenephosphonate ((153)Sm-EDTMP) day -14] and melphalan (140 mg/m(2) day -2) were chosen as the conditioning regimen to avoid potential lung complications. The patient received an infusion of 6.1 x 10(8)/kg mononuclear autologous cells on day 0. She achieved engraftment on day +23. Three years after transplantation, she continues to have complete remission. Samarium and melphalan constitute a well-tolerated regimen with potential antileukemic activity.

Adolescent↗
PubMed2003

[6-endo-trig mode cyclization to a hydrindanone using samarium (II) iodide].

Samarium (II) iodide has been employed to promote the vinylogous pinacol coupling reaction of aldehyde to alpha, beta-unsaturated ketones. The diastereoselectivity of 6-endo-trig mode products was changed by the addition of a proton source and/or HMPA and by the reaction temperature. The stereochemistry of the hydrindanone was controlled by the coordinated samarium species, resulting in the cis-orientation in respect of the hydroxyl group at C-4 and the juncture proton at C-3a under mild reaction conditions. Coronafacic acid has been synthesized from a hydrindanone prepared by the cyclization reaction of the enone-aldehyde with samarium (II) iodide.

Cyclization↗
PubMed1996

Clinical outcome after one year following samarium-153 particulate hydroxyapatite radiation synovectomy.

The clinical outcome and tolerability following treatment with samarium-153 particulate hydroxyapatite was evaluated in patients with persistent rheumatoid knee synovitis. The clinical review of 18 patients treated with intra-articular samarium-153 particulate hydroxyapatite combined with triamcinolone hexacetonide who had failed to obtain more than 4 weeks symptom relief from a prior intra-articular glucocorticoid injection was undertaken. No unwanted effects from the treatment were observed. Symptom relief was maintained in 56% patients at 6 months and in 44% of patients at 12 months following treatment. Median duration of symptom relief was 9 months. There was a significantly higher mean baseline Ritchie Articular Index in patients relapsing within 3 months and a trend towards earlier relapse in patients with higher indices of disease activity at the time of treatment. There was a trend towards earlier relapse in patients with a poor range of knee flexion at baseline and with worse indices of intra-articular radiopharmaceutical distribution. Samarium-153 particulate hydroxyapatite knee synovectomy is well tolerated and may be an effective treatment for carefully selected patients with persistent rheumatoid knee synovitis.

Adult↗
PubMed2003

Structure and reactivity of homoleptic samarium(II) and thulium(II) phospholyl complexes.

Potassium 2,5-di-tert-butyl-3,4-dimethylphospholide K(dtp) (9) was synthesised in 45 % yield from commercially available starting materials by using zirconacyclopentadiene chemistry. Reaction of the K salt of this bulky anion and of the previously described potassium 2,5-bis(trimethylsilyl)-3,4-dimethylphospholide K(dsp) (8) with SmI(2) in diethyl ether afforded the homoleptic samarium(II) complexes 7 and 6, respectively, whose solid-state structures, [[Sm(dtp)(2)](2)] (7 a) and [[Sm(dsp)(2)](2)] (6 a), are dimeric owing to coordination of the phosphorus lone pairs to samarium, as shown by X-ray crystallography. Reaction of 8 with TmI(2) in diethyl ether afforded [Tm(dsp)(2)(Et(2)O)], which could not be desolvated without decomposition. In contrast, the coordinated ether group of the solvate [Tm(dtp)(2)(Et(2)O)], obtained from 9 and TmI(2), could easily be removed by evaporation of the solvent and extraction with pentane at room temperature, and the monomer [Tm(dtp)(2)] (5) could be isolated and was characterised by X-ray crystallography. Presumably, steric crowding in 5 is too high for dimerisation to occur. Compound 5, the first Tm(II) homoleptic sandwich complex, is remarkably stable at room temperature in solution and did not noticeably react with nitrogen, in sharp contrast with other thulium(II) species. As expected, 5, 6 and 7 all reacted with azobenzene to give the trivalent complexes [Tm(dtp)(2)(N(2)Ph(2))] (13), [Sm(dsp)(2)(N(2)Ph(2))], (14) and [Sm(dtp)(2)(N(2)Ph(2))] (15), respectively; 13 and 14 were characterised by X-ray crystallography. Complex 5 immediately reacted with triphenylphosphane sulfide at room temperature to give [[Tm(dtp)(2)](2)(mu-S)] (16), which was characterised by X-ray crystallography, whereas samarium(II) complexes 6 and 7 did not noticeably react with Ph(3)PS over 24 h under the same conditions.

Journal Article↗
PubMed2006

Incident pain and analgesic consumption decrease after samarium infusion: a pilot study.

OBJECTIVE: The aim of this pilot study was to observe the variations of pain intensity on movement and at rest and the variation of analgesic drug consumption in patients with prostate cancer and painful bone metastases treated with a single dose of 1.0 mCi/kg of samarium-153 (153-Sm) lexidronam. DESIGN: Case series. SETTING: The Nuclear Medicine Unit and Pain Therapy and Palliative Care Unit, National Cancer Institute of Milan, Italy. PATIENTS: Thirteen outpatients with hormone refractory prostate cancer and painful multiple bone metastases. INTERVENTIONS: Infusion of a single dose of 1.0 mCi/kg of 153-Sm lexidronam, pain therapy, and the assessment of pain intensity at rest and on movement. MAIN OUTCOME MEASURES: Variation of pain intensity on movement and at rest by means of a verbal scale and the reduction of analgesic drug consumption 4 weeks after infusion of 153-Sm lexidronam. RESULTS: From baseline, 61.5% of patients reported a decrease of at least two levels of pain intensity on movement and 53.8% of patients had an improvement of pain at rest. Of the patients, 15.4% were not in pain at rest or on movement at baseline and continued to be free of pain 4 weeks after the administration of samarium. All ten patients, but one, who were on analgesic drugs before samarium infusion, reduced the regular drug administration or rescue medication. Bone marrow toxicity was mild and readily reversible in three patients. CONCLUSIONS: In patients with bone metastases, pain on movement is a frequent and often difficult clinical problem to treat and the most frequent cause of breakthrough pain. In patients with painful multiple bone metastases due to prostate cancer, the infusion of a single dose of 1.0 mCi/kg of 153-Sm lexidronam may be considered an effective and safe treatment for pain either at rest or during movement.

Aged↗
PubMed1995

The effects of samarium-cobalt magnets and pulsed electromagnetic fields on tooth movement.

The purpose of this study was to determine whether the application of either samarium cobalt magnets or pulsed electromagnetic fields could increase the rate and amount of orthodontic tooth movement observed in guinea pigs. In addition, the objective was to evaluate the effect of a magnetic field on bony physiology and metabolism and to monitor for possible systemic side effects. Fifteen grams of laterally directed orthodontic force were applied to move the maxillary central incisors of a sample of 18 young male Hartley guinea pigs divided into three groups: group 1, an orthodontic coil spring was used to move the incisors; group 2, a pair of samarium-cobalt magnets provided the tooth moving force; and group 3, a coil spring was used in combination with a pulsed electromagnetic field. The results showed that both the static magnetic field produced by the samarium-cobalt magnets and the pulsed electromagnetic field used in combination with the coil spring were successful in increasing the rate of tooth movement over that produced by the coil springs alone. The mechanism producing this effect appears to have involved a reduction in the "lag" phase often seen in orthodontic tooth movement. Both magnetically stimulated groups also showed increases in both the organization and amount of new bone deposited in the area of tension between the orthodontically moved maxillary incisors.

Animals↗
PubMed2002

A mechanistic study of the samarium(II)-mediated reduction of aryl nitro compounds to the corresponding crylamines. The crystal structures of [Sm[N(SiMe(3))(2)](2)(thf)](2)(mu(2)-O) and [(Me(3)Si)(2)N](2)Sm(thf)(mu-PhNNPh)Sm[N(SiMe(3))(2)](2).

Treatment of nitrobenzene and other various nitroarenes with 6 equiv of samarium(II) under strictly anhydrous conditions allows for the isolation of aniline or the corresponding arylamine. Reducing the number of samarium(II) equivalents allows for the isolation of intermediate species, e.g., azoarenes or hydrazines. Use of Sm[N(SiMe(3))(2)](2), in place of the typically used SmI(2), has allowed for the detailed examination of the aqueous and nonaqueous species formed in this reduction and has been instrumental in delineation of the stepwise reaction mechanism. This is the first time that the reaction intermediates of an organic reaction mediated by samarium(II) have been isolated and analyzed by (1)H NMR and X-ray crystallography.

Journal Article↗
PubMed2001

Samarium(0) and 1,1'-dioctyl-4,4'-bipyridinium dibromide: a novel electron-transfer system for the chemoselective reduction of aromatic nitro groups.

A mild and efficient electron-transfer method was developed for the chemoselective reduction of aromatic nitro groups using samarium(0) metal in the presence of a catalytic amount of 1,1'-dioctyl-4,4'-bipyridinium dibromide. This method was found to give the product aromatic amine in 79-99% yield with selectivity over a number of other functional and protecting groups such as alkene, azide, benzyl ether, nitrile, amide, halide, p-toluenesulfonamide, t-Boc, tert-butyldiphenylsilyl ether, and aliphatic nitro groups. Our results also indicate that samarium(0) plays an important role in the reduction process and that 1,1'-dioctyl-4,4'-bipyridinium dibromide acts as an electron-transfer catalyst and is essential in the activation of samarium(0) metal. The major active reducing agent responsible for the reduction is believed to be the radical cation species formed from 1,1'-dioctyl-4,4'-bipyridinium dibromide.

Journal Article↗
PubMed1996

Reductions, Reductive Alkylations, and Intramolecular Cyclizations of Acyl Silanes with Samarium Diiodide or Tributyltin Hydride.

A series of acyl silanes including aliphatic-, aromatic-, and bis-acyl silanes, as well as the acyl silanes bearing other substituents such as a bromine atom and alkenyl, succinimide, and carbonyl groups, were prepared, and their reactions with samarium diiodide or tributylstannane were studied. The reactions of acyl silanes occurred in various manners such as reductions, reductive alkylations, intramolecular radical cyclizations, pinacol couplings, aldol reactions, and Tishchenko reactions, depending on the nature of substrates and reaction conditions. Acyl silanes were generally reduced to give the corresponding alpha-silyl alcohols without transfer of silyl groups. Intramolecular radical cyclizations of 5-hexenoyl silanes and 1-silyl-1,5-pentanedione were realized to give alpha-silyl cyclopentanols and 1,2-cyclopentanediol derivatives, respectively. On treatment with samarium diiodide in tetrahydrofuran, 1-(trimethylsilyl)-1,6-hexanedione underwent a pinacol coupling reaction in the presence of t-BuOH, whereas it underwent a Tishchenko reaction in the presence of MeOH. The Tishchenko reaction of 1-silyl-1,5-pentanedione gave a delta-silyl-delta-lactone. On treating with samarium diiodide, 1-(trimethylsilyl)-1,5-hexanedione and 1,5-bis(trimethylsilyl)-1,6-hexanedione, underwent, respectively, intramolecular aldol reactions.

Journal Article↗
PubMed1997

Synthesis of Aminocyclitols by Intramolecular Reductive Coupling of Carbohydrate Derived delta- and epsilon-Functionalized Oxime Ethers Promoted by Tributyltin Hydride or Samarium Diiodide.

The intramolecular reductive coupling of a series of simple or polyoxygenated oxime ethers delta- or epsilon-functionalized with bromide, alpha,beta-unsaturated ester, aldehyde, or ketone groups is reported. The cyclization of a nitrile-tethered aldehyde is also studied. These reductive couplings are promoted by tributyltin hydride or samarium diiodide. The reactions proceed under mild conditions, in good chemical yield, and with high stereoselectivity. When applied to highly functionalized substrates derived from carbohydrates, this approach provides a selective entry to enantiomerically pure aminocyclitols of varying regio- and stereochemistry. In particular, the reductive coupling reaction of carbonyl-tethered oxime ethers promoted by samarium diiodide can be performed in a one-pot sequence, following a Swern oxidation step, allowing the direct transformation of hydroxyl-tethered oxime ethers into the corresponding aminocyclitols. Moreover, the resultant O-benzylhydroxylamine products of these cyclizations can be further reduced in situ with excess samarium diiodide, in the presence of water, to the corresponding amino alcohols in excellent yields. Some transformations of these compounds are discussed.

Journal Article↗
PubMed2000

Asymmetric Samarium-Reformatsky Reaction of Chiral alpha-Bromoacetyl-2-oxazolidinones with Aldehydes.

The samarium(II) iodide mediated asymmetric Reformatsky-type reaction of chiral 3-bromoacetyl-2-oxazolidinones with various aldehydes was studied. A series of chiral 4-substituted 2-oxazolidinones 1-3 and 5,5-disubstituted "SuperQuat" oxazolidinones 4-5 were employed as chiral auxiliaries of the alpha-bromoacetic acid. The reaction of 1 with various aldehydes gave the alpha-unbranched beta-hydroxy carboximides in good yields with high diastereomeric excess values (up to >99% de). The majority of the reaction product derived from 5,5-diphenyl SuperQuat 5 were highly crystallinity; a single recrystallization yielding a diastereomerically pure product with the other diastereomer not detectable by spectroscopic methods. The absolute configurations of the beta-hydroxy carboximides were determined by signs of optical rotations of the corresponding known ethyl esters referring to the literature values. Hydrolytic cleavage of the appended of beta-hydroxy moieties from the auxiliary SuperQuats was readily achieved under mild conditions using lithium hydroxide; the corresponding carboxylic acids and the returned SuperQuats were obtained in good yields without any evidence of racemization. The first step of the reaction is the reduction of the alpha-bromo group to produce the samarium enolate, which adds to an aldehyde. The absolute configuration of the adduct (7i) derive from benzaldehyde was found to be R, with the samarium enolate favoring the transition state predicted from chelation control of the reagent; this is in analogy to the discussion that has been used for the corresponding titanium enolate. The stereochemistry of the reaction may be explained by incorporating the Nerz-Stormes-Thornton chair transition structure model.

Journal Article↗
PubMed2002

Samarium(II)-mediated reactions of gamma,delta-unsaturated ketones. Cyclization and fragmentation processes.

[reaction: see text] On treatment with samarium(II) iodide, gamma,delta-unsaturated ketones undergo very different processes depending upon the nature of the reaction conditions. Employing samarium(II) iodide and MeOH, functionalized syn-cyclopentanol products are obtained stereoselectively. Mechanistic studies suggest that this cyclization occurs via a sequential reduction/intramolecular aldol reaction. With samarium(II) iodide and HMPA, products of a 4-exo-trig cyclization and of an interesting fragmentation reaction are observed.

Journal Article↗
PubMed2006

Separation of samarium and neodymium: a prerequisite for getting signals from nuclear synthesis.

(146)Sm (T(1/2) = 10(8) y) is a long-lived radionuclide which has been produced in significant amounts during burning in a supernova (SN). Detection of this SN produced long-lived radionuclide on Earth may be helpful for getting information on nuclear synthesis at the time of our solar system's formation. Only accelerator mass spectrometry (AMS) can determine such minute traces of (146)Sm still expected in the Earth's crust. However, the villain of (146)Sm measurement through AMS is its naturally occurring stable isobar (146)Nd which is a million times more abundant than the trace amount of (146)Sm. Therefore an efficient method for the separation of samarium and neodymium is required to measure (146)Sm through AMS. A simple liquid-liquid extraction (LLX) based method for separation of samarium and neodymium has been developed using radiometric simulation. Di-(2-ethylhexyl)phosphoric acid (HDEHP) has been used as the organic reagent. A very high separation factor ( approximately 10(6)) can be achieved when a solution containing samarium and neodymium is reduced by hydroxylamine hydrochloride followed by extraction with 0.1% HDEHP diluted in cyclohexane from 0.025 M HCl solution.

Journal Article↗
PubMed1998

Diffusion kinetics of samarium and neodymium in garnet, and a method for determining cooling rates of rocks

Experimental determinations of the diffusion coefficients of samarium and neodymium in almandine garnet and theoretical considerations show that one cannot assign a sufficiently restricted range of closure temperature, TC, to the samarium-neodymium decay system in garnet for the purpose of constraining the cooling rate. However, it is shown that the samarium-neodymium cooling age of garnet can be used to calculate both cooling rate and TC if the temperature and age at the peak metamorphic conditions are known.

Journal Article↗
PubMed2000

Samarium Sm-153 lexidronam for the palliation of bone pain associated with metastases.

BACKGROUND: In patients with bone pain due to metastatic disease, intravenous systemic radioisotope therapy may be a useful adjunct to other methods for palliating pain. METHODS: Various studies have been performed utilizing a short-lived radioisotope conjugated to a tetraphosphonate (samarium 153 lexidronam) both as an open label and as a double blinded, placebo-controlled study. Patients with varying tumor types including those of the prostate, breast, lung, and other sites were studied. Two dose levels were used (0.5 millicuries (mCi)/kg and 1.0 mCi/kg) with patients monitored for 16 weeks for efficacy (pain scores, opiod analgesic score, and quality of life) parameters and adverse events. RESULTS: All 3 studies showed that at the 1.0 mCi/kg dose level statistically significant improvement over placebo was observed by 4 weeks with relief of pain noted in many patients by 1 week. The only significant adverse event was transient myelosuppression with a nadir at 4-6 weeks and recovery by 8 weeks. Less than 10% of patients had National Cancer Institute Common Toxicity Criteria Grade III/IV bone marrow toxicity recorded. CONCLUSIONS: Systemic metabolic radiotherapy with samarium 153 lexidronam appears to be a safe and efficacious method for treating patients with bone pain. The shorter radioisotope half-life allows for a high dose rate to be delivered over a short period, which may have certain biologic benefits.

Bone Neoplasms↗
PubMed1994

Biocompatibility of new, clinically used, and recycled orthodontic samarium-cobalt magnets.

The aim of this study was to compare the cytotoxic effect of new, clinically used, and recycled samarium-cobalt magnets (SmCO5). Cytotoxicity was assessed by two in vitro methods, the millipore filter method and an extraction method. In the filter method, the test material and the target cells are separated by a thin, permeable membrane. The test assesses the cytotoxicity of both water soluble and nonwater soluble components of the test material. The extraction test, which has a higher sensitivity, assesses the cytotoxicity of water soluble components only. According to the filter method, one magnet (new) showed a mild cytotoxic effect; all other tested magnets showed no cytotoxicity. Judged by the extraction test, new as well as clinically used magnets demonstrated a weak cytotoxic effect, suggesting the presence of a small amount of leachable cytotoxic components. The level of exerted cytotoxicity of such components was significantly lower for clinically used than for new magnets. When recycled magnets were tested, the cytotoxicity had significantly decreased, (p < 0.001), and the cytotoxicity could be considered negligible. The results thus revealed that SmCO5 magnets can be recycled with maintained good biocompatibility. Because a small amount of water soluble cytotoxic agents seem to leach out from new partially stainless steel-coated samarium-cobalt magnets, it is recommended that they be stored in water for 24 hours before clinical use, thereby conceivably decreasing the oral exposure of water soluble cytotoxic agents.

Animals↗
PubMed1995

Extent and flux density of static magnetic fields generated by orthodontic samarium-cobalt magnets.

The aim of this study was to measure and to analyze the extent and flux density of static magnetic fields generated by commercially available samarium-cobalt magnets used in orthodontics. The flux density was measured with a gaussmeter and a Hall probe with the magnets mounted in clinically relevant positions, i.e., in attractive and in repelling positions and also in the single position. Furthermore, the flux density between new and clinically used and recycled magnets was compared. It was found that the maximum flux density was generated at the pole faces and that magnets in attractive positions produced the highest flux density (2.2 kG), followed by the single magnet (2.0 kG) and the repelling magnets (1.7 kG). The flux density decreased rapidly (exponentially) with increased distance from the magnets. The flux density was approximately the same or less than the flux density of the earth magnetism (0.3 to 0.7 G) 60 mm from the attractive magnets, 50 mm from the single magnets, and 35 mm from the repelling magnets. The difference in flux density between new and clinically used and recycled samarium-cobalt magnets was negligible. Thus, the static magnetic field exposure of surrounding tissues can be assumed to be low, and the conceivable risk of harmful biologic effects must be regarded as small and limited when the tested orthodontic magnets are used clinically.

Cobalt↗