153Sm metallic-hydroxide macroaggregates: An improved preparation for radiation synovectomy

A new type of preparation employing¹⁵³Sm metallic-hydroxide macroaggregates (¹⁵³Sm-MHM) for radiation synovectomy was developed. The radiopharmaceutical was prepared by reacting the aqueous solution of¹⁵³SmCl₃ with sodium borohydride solution in 0.5N NaOH. Microscopic analysis showed that¹⁵³Sm-MHM mean particle size was 4 m (range 1–15 m) avoiding the formation of fine particles (<1 m) which were¹⁵³Sm-hydroxide macroaggregates preparations (¹⁵³Sm-HM). Also, suspension properties as sedimentation rate, were better for¹⁵³Sm-MHM than for¹⁵³Sm-hydroxyapatite and¹⁵³Sm-HM. Biological studies in normal rabbits demonstrated high retention into de Knee joint space even at 48 h after administration of¹⁵³Sm-MHM (>99%).     

Chemical process study on the separation of gadolinium-153

Three routes of chemical processes for a multicurie production of¹⁵³Gd have been established and demonstrated using one gram of Eu₂O₃ as target irradiated under a neutron flux of 5.0·10¹³n/cm²/s for 42 days. Simulated experiments with the synthetic solution containing appropriate amounts of Gd and Eu and the tracers were performed throughout the established chemical process for verifying its feasibility and the effectiveness. The results show that a high specific activity of 100 Ci/g Gd with the desired radionuclide purity of greater than 99.999% of¹⁵³Gd can be obtained. The chemical yield and processing time among the processes were compared.     

A solid phase radioimmunoassay for triiodothyronine using antibody-immobilized serum albumin microspheres

A solid phase radioimmunoassay for triiodothyronine (T₃) has been developed using antibody-immobilized serum albumin microspheres. Antibody albumin microspheres were prepared using a spinning disc aerosol generator. The low density of the antibody-albumin microspheres gives greater mobility for the particles there by ensuring better kinetics to the antigen-antibody reaction. The assay has a single incubation of one hour at 37° C and the separation of the antigen-antibody complex is accomplished by centrifugation. The sensitivity of this assay is 0.3 ng/cm³ and has a range of 0.3–4 ng/cm³.     

A potential bone tumor therapeutic agent153Sm-EDTMP: Its synthesis and preliminary structure analysis

Samarium-153-EDTMP (ethylene diamine tetramethylene phosphonate), for its promising biological properties, has been proved as a palliating therapeutic agent for boné cancer in human beings. In this article, we present the results on synthesis and structure analysis of Samarium-153-EDTMP. In a basic medium,¹⁵³Sm-EDTMP can be readily prepared with a complexing yield not less than 98%, and it is confirmed that the ratio of the ligand to Sm is 11, and the charge of¹⁵³Sm-EDTMP is negative two.     

Preparation of samarium-153-EDTMP and determination of its radiochemical purity using paper chromatography

Samarium-153-ethylenediaminetetramethylenephosphonate (¹⁵³Sm-EDTMP) has been used to palliate pain resulting from bone cancer. This paper describes the preparation of¹⁵³SmCl₃ from irradiated natural samarium and the ability of¹⁵³Sm to complex with EDTMP in liquid and in freeze-dried forms. The evaluation of radiolabeled EDTMP was done by paper chromatography. A rapid evaluation of free¹⁵³SmCl₃ and¹⁵³Sm-EDTMP was developed using a miniaturized chromatographic system.     

(α, xn) reactions on natural samarium

A stack of natural samarium was bombarded with 87 MeV alpha particles. Cumulative cross sections for the production of¹⁵³Gd,¹⁵¹Gd,¹⁴⁹Gd,¹⁴⁷Gd,¹⁴⁶Gd have been studied using gamma-ray spectroscopy.     

Study on analysis of153Sm-EDTMP stability in vitro and vivo by HPLC

The behavior of¹⁵³Sm-EDTMP in vitro and vivo is analyzed by the size exclusion HPLC. The experimental results show that EDTMP amounts have an obvious effect on the stability in vitro and uptake of¹⁵³Sm-EDTMP in the liver. HPLC analysis of urine sample indicates that¹⁵³Sm-EDTMP es excreted in the original form. The behavior in vivo of¹⁵³Sm-EDTMP containing 4 μg is similar to that of¹⁵³Sm-EDTMP containing 50 μg EDTMP at 1 h post-injection.     

Extraction and separation of141Ce and153Gd with HDEHP

Studies on liquid-liquid extraction of trace level cerium and gadolinium,¹⁴¹Ce and¹⁵³Gd, from HCl and HNO₃ media with liquid cation exchanger, HDEHP reveal that a quantitative separation of the elements from an admixture of the two radioisotopes can be achieved with 0.1% HDEHP and 0.01N HCl. The condition is also valid for separation of trace amount of¹⁵³Gd from bulk or macro quantity of cerium.     

Rapid and accurate determination of89/90Sr in radioactive samples by Cerenkov counting

An improved and rapid method for determination of⁹⁰Sr via its daughter nuclide,⁹⁰Y, in aqueous samples from the low-level radioactive wastes by Cerenkov counting was established. This technique is applicable to beta particles maximum energies greater than 0.263 MeV in aqueous solution. A comparison of⁹⁰Sr determination by Cerenkov counting and standard wet chemical separation techniques indicates a high degree of correlation and excellent agreement. For a 20 ml aqueous sample following the prescribed experimental conditions and a 60 min counting interval, the detection limit was 0.20 dpm/ml (0.10 pCi/ml), and the relative deviation is less then 5%.     

Preparation of113mIn and99mTc-microaggregated human serum albumin for liver scanning

Higher than 90% of^113mIn radioactivity was bound to microaggregates. The liver uptake in mice was (80%) with low lung uptake (1.3%). With respect to^99mTc-microaggregated albumin, the radiochemical yield was higher than 95%. The liver uptake in mice was about (80%) with low lung uptake (1.7%). The stability of the microaggregates was followed for two months.     

Chemical study on the separation and purification of promethium-147

A chemical process for the separation of¹⁴⁷Nd/¹⁴⁷Pm from fission products of synthetic radioactive waste solution has been developed. The process includes: (1) denitration, (2) removal of high concentration of uranium by 30% TBP/kerosene extraction, (3) removal of⁹⁵Nb,¹⁰³Ru,¹³⁷Cs and part of⁹⁰Sr by 50% TBP/dodecane extraction, (4) separation of¹⁴⁷Nd/¹⁴⁷Pm from part of⁹⁰Sr and⁹⁵Zr by oxalic acid precipitation, and (5) removal of¹⁴⁴Ce by mixture of 0.4M D2EHPA and 0.2M TBP extraction. Experimental results indicate that the recovery of¹⁴⁷Nd/¹⁴⁷Pm in the final separated solution is about 90%. The purification of¹⁴⁷Nd and¹⁴⁷Pm from some other rare earth elements, viz.¹⁵³Sm,¹⁵⁴Eu and¹⁴⁴Ce was further investigated by using a Dowex 50W×8 ion-exchanger. Parameters of flow rate, eluent concentration and pH were examined. The results show that the recovery and radionuclide purity of¹⁴⁷Nd plus¹⁴⁷Pm under the present separation conditions are 77.8% and 98.6% for diethylenetriaminepentaacetic acid (DTPA) and 87.3% and 99.5% for nitrilotriacetic acid (NTA), respectively.     

Determination of Samarium in rocks by epithermal neutron-activation analysis

Summary A non-destructive neutron-activation method for the determination of samarium in rocks, based on activation with epithermal neutrons, is described. By this means the formation of¹⁵³Sm, as compared to most interfering radionuclides, is considerably higher than by thermal neutron activation. The precision of the method is 2–3% in the range of 3–25 ppm, and the sensivity is about 0,1 ppm. Results are presented for some standard rocks. The influence of other rare earth nuclides on the measurement of the 41 KeV X-ray of¹⁵³Sm has been investigated.

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Zerstörungsfreie Bestimmung von Samarium in Gesteinen durch Aktivierungsanalyse mit epithermischen Neutronen

Zusammenfassung Die Bildung von¹⁵³Sm ist hierbei im Vergleich zu den meisten störenden Radionukliden beträchtlich größer als bei der Aktivierung mit thermischen Neutronen. Die Präzision des Verfahrens beträgt 2–3% im Bereich von 3–25 ppm, die Empfindlichkeit etwa 0,1 ppm. Für einige Standardgesteine werden die Ergebnisse angeführt. Der Einfluß anderer Nuklide Seltener Erden auf die Messung der 41 keV Röntgenstrahlung von¹⁵³Sm wurde untersucht.

     

Octyl-functionalized hybrid magnetic mesoporous microspheres for enrichment of low-concentration peptides prior to direct analysis by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Octyl‐functionalized hybrid magnetic mesoporous (Fe₃O₄·nSiO₂·meso‐hybrid‐C8) microspheres were synthesized and applied in the isolation and pre‐concentration of low‐concentration peptides prior to direct analysis by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS). Such microspheres possess high surface area (324 m²/g), hydrophobic group (C8), relatively large pore volume (0.304 cm³/g), uniform pore diameter (~3.7 nm), and magnetic responsivity, which make them a simple and efficient kind of adsorbent for the enrichment of low‐concentration peptides. For bovine serum albumin (BSA, 15 fmol μL^–1) digest, after concentration by Fe₃O₄·nSiO₂·meso‐hybrid‐C8 microspheres, the enrichment performance was evidently better than those obtained by solvent evaporation and C8‐functionalized magnetic particles, and comparable to those obtained by commercial Anchor chip target and ZipTipC18 pipette tip. Such microspheres were further applied in the enrichment of the tryptic digests of rat cerebellum proteins and endogenous peptides of crude human serum, and more peaks with higher signal‐to‐noise (S/N) ratio were obtained than before pre‐concentration. Furthermore, the pre‐concentration reproducibility of magnetic microspheres for biological samples was good, and the limit of detection (LOD) for BSA digests by MALDI‐TOF MS was decreased by at least one order of magnitude compared with that obtained without pre‐concentration. All the above‐mentioned results indicate that the synthesized Fe₃O₄·nSiO₂·meso‐hybrid‐C8 microspheres are promising for the enrichment of low‐concentration peptides from complex biosamples. Copyright © 2011 John Wiley & Sons, Ltd.     

Polyelectrolyte mediated formation of hydroxyapatite microspheres of controlled size and hierarchical structure

The understanding of the role of polyelectrolytes in the synthesis of inorganic materials could provide effective routes towards design of advanced materials. In this study, negatively charged poly(styrene sulfonate) (PSS) is employed as a modifier in hydrothermal synthesis of hydroxyapatite (HA). The results indicate that both the morphology and particle size could be well controlled by adjusting the PSS concentration. The presence of PSS (within the range of 0–9.6 wt%) modified the growth pattern of HA crystallites and results in particles from the ribbons to microspheres. The building units of various microspheres change from nanofibers to nanorods or nanoplates. Along with that, the microspheres become smaller and more compact at higher PSS concentrations. The adsorption of PSS onto certain crystal faces as well as the complexing effect of PSS with Ca²⁺ can be considered as the controlling factors which determine the influence of PSS on the growth mode. The drug release study indicates that the flower-like HA microspheres can be possibly used as effective carriers for biomedical applications. The present synthesis method is simple and controllable, and can provide a convenient route to synthesize uniform HA microspheres with different sizes and hierarchical structures.     

Surface molecularly imprinted magnetic microspheres for the recognition of albumin

A new approach, combining metal coordination with the molecular imprinting technique, was developed to prepare affinity materials. Magnetic poly(glycidyl methacrylate) microspheres in monosize form were used for specific recognition toward the target protein. The magnetic poly(glycidyl methacrylate) microspheres were prepared by dispersion polymerization in the presence of magnetite nanopowder. Surface imprinted magnetic poly(glycidyl methacrylate) microspheres based on metal coordination were prepared and used for the selective recognition of human serum albumin. Iminodiacetic acid was used as the metal coordinating agent and human serum albumin was anchored by Cu²⁺ ions on the surface of magnetic poly(glycidyl methacrylate) microspheres by metal coordination. The magnetic poly(glycidyl methacrylate) microspheres were coated with a polymer formed by condensation of tetraethyl orthosilicate and 3‐aminopropyltrimethoxysilane. The human serum albumin imprinted magnetic poly(glycidyl methacrylate) microspheres were characterized by scanning electron microscopy, attenuated total reflectance Fourier transform infrared spectroscopy and particle size analysis. The maximum adsorption capacity of human serum albumin imprinted magnetic poly(glycidyl methacrylate) microspheres was 37.7 mg/g polymer at pH 6.0. The selectivity experiments of human serum albumin imprinted magnetic poly(glycidyl methacrylate) microspheres prepared with different concentrations in the presence of lysozyme, bovine serum albumin and cytochrome C were performed in order to determine the relative selectivity coefficients.     

Rapid determination of radium isotopes by alpha spectrometry

An efficient analytical method for the determination of low-levels of²²⁶Ra and²²⁴Ra by alpha spectrometry is described. A cation exchange column was used to separate the analyte from other constituents in the sample (1–50 mL). After preconcentration and separation, the radium was electrodeposited onto a stainless steel disc from a solution of ammonium oxalate and hydrochloric acid. The electrodeposition was accomplished by the addition of platinum in microgram amounts. Linear responses were greater than two orders of magnitude. Detection limits of the procedure, taken as three times the standard deviation of several reagent blank analyses, were (1.8±0.3)×10^–4 Bq and (2.9±0.3)×10^–4 Bq for²²⁶Ra and²²⁴Ra, respectively. Recoveries of²²⁶Ra and²²⁴Ra ranged from 90% to 100% when samples of drinking water, well water, and dissolved bones were analyzed. Precision was calculated to be less than 5% for the determination of²²⁶Ra. Matrix effects were studied for salts of barium, magnesium, iron, and calcium.     

Production of radiochemically and radionuclidically pure153Sm for medical applications

A procedure is described for the large scale production of radiochemically and radionuclidically pure¹⁵³Sm economically, from neutron irradiated natural Sm targets. Cation-exchange chromatography using 200–400 mesh Dowex-50×8 resin in the elution mode was used with 0.2M -hydroxyisobutyric acid (-HIBA) as the eluent at pH 4.7±1 and at 26±1 °C for this purpose. Typical decontaminations of carrier-free^(155+156)Eu radioactive impurities, of the order of 5×10², could be achieved in individual fractions, from millicurie amounts of¹⁵³Sm activity produced in milligram quantities of heavily neutron-irradiated natural Sm targets. Even though the¹⁵³Sm yields were at about 3% at these decontamination levels of impurities, the yields increased to an average of about 50% at about 95% level of decontamination of these impurities. It has been shown that the method is successful for producing radiochemically and radionuclidically pure¹⁵³Sm in sufficiently high radioactive concentrations for its probable conversion into¹⁵³SmEDTMP complex, a potential radiopharmaceutical useful in the palliative therapy of metastatic bone cancer.     

Epithermal neutron activation analysis of uranium by neptunium-239 using high resolution gamma-spectrometry

The possibility to use the most intensive gamma-peak of²³⁹Np for INAA of uranium with epithermal neutrons and high resolution Ge(Li)-spectrometry is evaluated. A way for calculation of the peak area of overlapping peaks of¹⁵³Sm and²³⁹Np is proposed. This can be used in other similar cases in the practice of NAA. On this basis a scheme for NAA of uranium in geological objects is proposed. Lower detection limit is 8·10⁻⁸ g U the precision 5–10% (relative standard deviation). The accuracy is demonstrated by the analysis of some geological standard reference materials.     

Variations in radionuclide concentrations and size distribution of radioactive particles from the Chinese nuclear weapon test of October 16, 1980

Debris from Chinese twenty-sixth nuclear explosion test (October 16, 1980) was collected by a high volume air sampler equipped with five-stage cascade impactors at the ground level in Fukuoka, Japan. The variations of radionuclide concentrations were measured for a period of about ten months following the test. The fallout seemed to be injected into the lower stratosphere as well as the troposphere because the effect persisted for about eight months until June 1981. The¹⁴¹Ce/⁹⁵Zr and¹⁴¹Ce/¹⁴⁴Ce of the particles smaller than 1.1 μm were relatively constant in spite of different collection periods. However, in the particle range larger than 1.1 μm, depletion of¹⁴¹Ce atom was observed and it was greater in the larger particles, but it reached gradually a constant value as time passed. This variation pattern was explained by the time difference between particle formation and detonation and the height of the fireball when the particles were formed.     

Formation of zein spheres by evaporation-induced self-assembly

Zein is an amphiphilic protein capable of self-assembly into microspheres. Zein microspheres may form by evaporation-induced self-assembly (EISA) of zein solutions in ethanol/water. The formation of microspheres is of particular interest for the development of delivery systems. Zein solutions in ethanol/water 75?% (v/v) were slowly evaporated to promote self-assembly of microspheres. The ethanol content of the solvent decreased during EISA changing solvent polarity which induced self-assembly of zein particles. The growth of zein spheres was modeled from the hydrophobic and hydrophilic contributions to the interfacial free energy (R ²?=?0.92). The good fit indicated that during EISA zein microspheres increased in size due to hydrophobic interactions between zein molecules. The model may allow the prediction of evaporation time and thus control over microsphere size.