Design and synthesis of Ac radioimmunopharmaceuticals

The alpha-particle-emitting radionuclides ²¹³Bi, ²¹¹At, ²²⁴Ra are under investigation for the treatment of leukemias, gliomas, and ankylosing spondylitis, respectively. ²¹³Bi and ²¹¹At were attached to monoclonal antibodies and used as targeted immunotherapeutic agents while unconjugated ²²⁴Ra chloride selectively seeks bone. ²²⁵Ac possesses favorable physical properties for radioimmunotherapy (10 d half-life and 4 net alpha particles), but has a history of unfavorable radiolabeling chemistry and poor metal-chelate stability. We selected functionalized derivatives of DOTA as the most promising to pursue from out of a group of potential ²²⁵Ac chelate compounds. A two-step synthetic process employing either MeO–DOTA–NCS or 2B–DOTA–NCS as the chelating moiety was developed to attach ²²⁵Ac to monoclonal antibodies. This method was tested using several different IgG systems. The chelation reaction yield in the first step was 93±8% radiochemically pure (n=26). The second step yielded ²²⁵Ac–DOTA–IgG constructs that were 95±5% radiochemically pure (n=27) and the mean percent immunoreactivity ranged from 25% to 81%, depending on the antibody used. This process has yielded several potential novel targeted ²²⁵Ac-labeled immunotherapeutic agents that may now be evaluated in appropriate model systems and ultimately in humans.     

Cytotoxic and genotoxic effect of the [166Dy]Dy/166Ho-EDTMP in vivo generator system in mice

Multiple myeloma and other hematological malignancies have been treated by myeloablative radiotherapy/chemotherapy and subsequent stem cell transplantation. [¹⁶⁶Dy]Dy/¹⁶⁶Ho-ethylenediaminetetramethylene phosphonate (EDTMP) forms a stable in vivo generator system with selective skeletal uptake in mice; therefore, it could work as a potential and improved agent for marrow ablation. Induced bone marrow cytotoxicity and genotoxicity are determined by the reduction of reticulocytes (RET) and elevation of micronucleated reticulocyte (MN-RET) in peripheral blood and ablation by bone marrow histological studies. The aim of this study was to determine the bone marrow cytotoxic and genotoxic effect of the [¹⁶⁶Dy]Dy/¹⁶⁶Ho-EDTMP in vivo generator system in mice and to evaluate by histopathology its myeloablative potential.

Enriched ¹⁶⁶Dy₂O₃ was irradiated and [¹⁶⁶Dy]DyCl₃ was added to EDTMP in phosphate buffer (pH 8.0) in a molar ratio of 1:1.75. QC was determined by TLC. Dy-EDTMP complex was prepared the same way with nonirradiated dysprosium oxide. A group of BALB/c mice were intraperitoneally injected with the radiopharmaceutical and two groups of control animals were injected with the cold complex and with 0.9% sodium chloride, respectively. A blood sample was taken at the beginning of the experiments and every 48 h for 12 days postinjection. The animals were sacrificed, organs of interest taken out and the radioactivity determined. The femur was used for histological studies. Flow cytometry analysis was used to quantify the frequency of RET and MN-RET in the blood samples. The MCNP4B Monte Carlo computer code was used for dosimetry calculations.

Radiochemical purity was 99% and the mean specific activity was 1.3 MBq/mg. The RET and MN-RET frequency were statistically different in the treatment at the end of the 12-day period demonstrating cytotoxicity and genotoxicity induced by the in vivo generator system. The histology studies show that there was complete, or almost complete, acellularity, which means significant suppression of the bone marrow activity. Bone marrow absorbed dose was 18–23 Gy. [¹⁶⁶Dy]Dy/¹⁶⁶Ho-EDTMP induces cytotoxicity, genotoxicity and severe myelosuppression in mice. Potentially, it is a good agent for use in humans.     

基质细胞支持的体外扩增造血细胞对致死剂量照射小鼠造血恢复的促进作用

目的 研究基质细胞支持条件下体外扩增的造血细胞回输体内后，促进经致死剂量照射小鼠造血功能恢复的作用。方法 在培养的小鼠骨髓基质细胞层存在的条件下，加入或不加入几种细胞因子组合，分别在小鼠骨髓单个核细胞液体培养体系中进行造血细胞体外扩增。将不同条件下扩增的细胞经尾静脉回输至经致死剂量照射的小鼠体内，并与单纯细胞因子存在条件下的扩增及末扩增造血细胞进行比较，动态观察小鼠的外周血象变化及其一般状况和生存宰。结果 ①单纯细胞因子介导小鼠骨髓单个核细胞(BMMNC)体外扩增后并不能增进这些细胞促进造血恢复的能力；②含有骨髓基质细胞底层的体外扩增，无论是否加入细胞因子，均有明显的促进移植受体造血功能迅速恢复的作用。     

Retention studies of recoiling daughter nuclides of 225Ac in polymer vesicles

Alpha radionuclide therapy is steadily gaining importance and a large number of pre-clinical and clinical studies have been carried out. However, due to the recoil effects the daughter recoil atoms, most of which are alpha emitters as well, receive energies that are much higher than the energies of chemical bonds resulting in decoupling of the radionuclide from common targeting agents. Here, we demonstrate that polymer vesicles (i.e. polymersomes) can retain recoiling daughter nuclei based on an experimental study examining the retention of ²²¹Fr and ²¹³Bi when encapsulating ²²⁵Ac.     

How to calculate lead concentration and concentration uncertainty in XRF in vivo bone lead analysis

The authors provide a substantial correction for calculating estimates of lead concentration and uncertainty for in vivo X-ray fluorescent bone analysis with Cd-109 source. Based on general principles, they provide mathematical techniques for propagation of uncertainties in XRF analysis. They give additional considerations for lowering the detection limit and improving spectral data quality.     

Photochemical internalization (PCI) of bleomycin is equally effective in two dissimilar leiomyosarcoma xenografts in athymic mice

BackgroundPhotochemical internalization (PCI) is a novel technique for delivery of active macromolecules into cancerous cells, via light activation of a specific photosensitizer and a low dose systemic drug. Numerous pre-clinical studies and one clinical trial have confirmed the treatment potential in carcinomas. Soft tissue sarcomas are rare and generally resistant to radio- and chemotherapy. Due to treatment resistance and surgical morbidity in sarcoma care, we seek to increase knowledge on PCI effects in sarcomas by studying two different, but closely related leiomyosarcomas.MethodsMES-SA and SK-LMS-1 tumours were established in the leg muscles of athymic mice. Treatment effects after AlPcS_2a-PCI of bleomycin, PCI with no drug (photodynamic therapy, PDT) and control groups were evaluated by: 1) assessment of tumour growth, 2) uptake of contrast agent during MRI and 3) histopathology.ResultsPCI of bleomycin induced a similar and significant increase in time to reach the end point in both tumour models, while neither responded to AlPcS_2a-PDT. In the MES-SA tumours PCI reduced the growth rate, while in the SK-LMS-1 tumours the growth was blocked for 12 days followed by exponential growth close to that of untreated tumours. SK-LMS-1 tumours were more homogenously and better vascularized than MES-SA. After PCI the vascular shutdown was more complete in the SK-LMS-1 tumours than in the MES-SA tumours.ConclusionsAlPcS2a-based PCI, but not PDT, induced significant tumour growth delay in the evaluated sarcomas. Cellular responsiveness to bleomycin and tumour vascularity are identified as predictive markers for PCI treatment effects.     

电离辐射后小鼠骨髓组成中结合珠蛋白的表达规律研究

目的研究照射前后结合珠蛋白在小鼠骨髓中的表达和分布，及其与骨髓细胞周期进程改变及凋亡的可能关联。方法用RT-PCR，Western blotting及流式细胞术的方法检测骨髓细胞Hp mRNA及细胞内外Hp蛋白的存在，及其辐射后的变化。用流式细胞术的方法分析了骨髓细胞中Hp阴性及阳性细胞群周期分布及凋亡率的差异。结果在骨髓细胞中检测到Hp mRNA的存在，而且8Gy照射后24h较正常小鼠有明显升高。骨髓细胞内及外液中检测到Hp蛋白的存在，同样8Gy照射后24h较正常小鼠亦呈明显升高。流式细胞术检测发现小鼠骨髓细胞中部分细胞含有Hp蛋白，照射后Hp阳性细胞的比例逐渐增加，并有着较好的时效关系和剂量依赖关系。骨髓Hp阳性细胞与阴性细胞的细胞周期分布存在显著的差异。在照射后6h骨髓细胞凋亡率随照射剂量增加而明显增加，而Hp^ 细胞凋亡率增加不明显。结论小鼠骨髓组织中可以检测到结合珠蛋白的存在，并且在辐射后有明显的增加，骨髓细胞中Hp阴、阳性细胞的周期分布和凋亡存在明显的差异。推测Hp可能参与辐射诱导骨髓损伤的修复过程。     

氡暴露致小鼠骨髓细胞的DNA损伤

目的 研究氡暴露致小鼠骨髓细胞的DNA损伤。方法 采用雄性BALB/C小鼠24只,随机分为4组,每组6只,除对照组外,处理组小鼠整体暴露于多功能生态氡室,吸入氡及其子体的累积剂量分别为27(低剂量组)、52(中剂量组)和105(高剂量组)工作水平月(WLM)。采用单细胞凝胶电泳(SCGE)、微核(MN)实验、激光共聚焦显微镜(LSCM)检测小鼠骨髓细胞的DNA链断裂、微核细胞率及凋亡率,观察氡暴露致小鼠骨髓细胞的DNA损伤。结果 高剂量氡暴露可造成小鼠骨髓细胞DNA断裂,尾长和尾DNA百分含量与对照组相比,差异有统计学意义(F=201.9,40.78,P<0.05);微核率和凋亡率增加差异有统计学意义(F=16.28,41.62,P<0.05)。而中、低剂量组则无明显改变。结论 高剂量氡暴露引起DNA损伤,从而对小鼠骨髓细胞产生毒效应。     

γ射线全身照射后小鼠骨髓造血细胞IL-3基因表达的原位PCR检测及其意义

目的 探讨内源性IL-3基因表达在骨髓辐射损伤后修复中的作用。方法 5.5Gy<⁶⁰Coγ射线全身照射78只LACA小鼠, 于照射后4周内分批活杀, 将骨髓进行HE染色, 并进行内源性IL-3基因表达的免疫组化、原位杂交和原位反转录PCR检测。结果 照射后4周内小鼠骨髓出现明显损伤及损伤后重建现象。免疫组化观察IL-3于修复期造血细胞浆内明显增多, 尤以照后21天其量达高峰, 而原位杂交则显示其mRNA于照射后10～21天为弱阳性, 尤以照射后15天明显。原位反转录PCR显示IL-3mRNA于修复期造血细胞浆内明显增多, 尤以照射后10～15天为甚。结论 原位反转录PCR能客观反映IL-3基因表达在骨髓辐射损伤后的变化规律, 且内源性IL-3基因表达在骨髓辐射损伤后造血功能重建中可能起明显促进作用。     

Recognition of cortical bone resorption in metabolic bone disease in vivo

This is an outline of radiologic assessment of cortical bone resorption for improved diagnosis of metabolic bone diseases by simple radiographic means: microradioscopy and morphometry. The methodology permits separate assessment of endosteal, intracortical, and periosteal resorption and an evaluation of both the quantity and the quality of cortical bone.     

放射损伤小鼠骨髓组织中bFGF、VEGF的表达

目的　探讨放射损伤对小鼠骨髓组织中bFGF、VEGF表达的影响。方法　采用免疫组织化学SABC法 ,检测昆明小鼠经 6 0Gy6 0 Coγ射线一次性全身均匀照射后不同时间骨髓组织中bFGF、VEGF表达水平的变化。结果　放射损伤后 ,小鼠骨髓组织中bFGF、VEGF表达水平显著低于正常组 (P <0 0 1) ,随时间延长 ,骨髓组织中bFGF、VEGF表达有所恢复 ,但 14d时仍未恢复正常 ;骨髓组织中bFGF表达与VEGF表达呈正相关 (r=0 82 4 ,P <0 0 1)。结论　辐射所致骨髓微环境损伤与骨髓组织中bFGF、VEGF表达异常有关     

川芎嗪对小鼠骨髓基质细胞内皮抑素表达的影响

目的探讨同基因骨髓移植(BMT)小鼠骨髓基质细胞内皮抑素(endostatin,ES)的表达及川芎嗪对其影响。方法取健康BALBc小鼠,随机分为3组正常组(不做处理),骨髓移植对照组(BMT组)和骨髓移植川芎嗪治疗组(川芎嗪组)。BMT组和川芎嗪组分别胃饲生理盐水02ml只和川芎嗪注射液每次2mg只,2次d。在BMT后第7、14、21、28天处死小鼠,采用免疫组化、Westernblot方法检测骨髓基质细胞中ES蛋白表达水平,RTPCR检测骨髓基质细胞中ESmRNA表达水平。结果BMT后第7、14、21、28天川芎嗪组和BMT组ESmRNA和蛋白表达水平均显著低于正常组(P<005或P<001),随着时间延长其表达逐渐增高。BMT后第14、21、28天川芎嗪组ES表达水平始终低于BMT组(P<005);但骨髓有核细胞计数高于BMT组(P<005或P<001)。结论川芎嗪能反馈调节BMT小鼠骨髓基质细胞新血管生成抑制因子的表达,促进骨髓微环境的修复,加速移植后骨髓的造血重建。     

[Dy]Dy/Ho hydroxide macroaggregates: an in vivo generator system for radiation synovectomy

Radiation synovectomy is an effective treatment in patients suffering from inflammatory-rheumatoid and degenerative joint diseases. The aim of this work was to examine the feasibility of preparing dysprosium-166 (¹⁶⁶Dy)/holmium-166(¹⁶⁶Ho) hydroxide macroaggregates ([¹⁶⁶Dy]Dy/¹⁶⁶Ho-HM) as an in vivo generator for radiation synovectomy evaluating whether the stability of ¹⁶⁶Dy-HM and ¹⁶⁶Ho-HM complexes is maintained when the daughter ¹⁶⁶Ho is formed. The Monte Carlo (MCNP4B) theoretical depth dose profile for the in vivo [¹⁶⁶Dy]Dy/¹⁶⁶Ho generator system in a joint model was calculated and compared with that produced by ⁹⁰Y, ¹⁵³Sm and ¹⁶⁶Ho. ¹⁶⁶Dy was obtained by neutron irradiation of enriched ¹⁶⁴Dy₂O₃ in a Triga Mark III reactor. Macroaggregates were prepared by reaction of [¹⁶⁶Dy]DyCl₃ with 0.5 M NaOH in an ultrasonic bath. [¹⁶⁶Dy]Dy/¹⁶⁶Ho-HM was obtained with radiochemical purity >99.5% and with the majority of particles in the 2–5 μm range. In vitro studies demonstrated that the radio-macroaggregates are stable in saline solution and human serum without a significant change in the particle size over 14 d, suggesting that no translocation of the daughter nucleus occurs subsequent to β⁻ decay of ¹⁶⁶Dy. Biological studies in normal rats demonstrated high retention in the knee joint even 7 d after [¹⁶⁶Dy]Dy/¹⁶⁶Ho-HM administration. The Monte Carlo (MCNP4B) theoretical depth dose profiles in a joint model, showed that the in vivo [¹⁶⁶Dy]Dy/¹⁶⁶Ho generator system would produce 25% and 50% less radiation dose to the articular cartilage and bone surface, respectively, than that produced by ⁹⁰Y or pure ¹⁶⁶Ho in a treatment with the same therapeutic dose to the synovium surface. Despite that ¹⁵³Sm showed the best depth dose profile sparing doses to healthy tissues, the use of ¹⁶⁶Dy could provide the advantage of being applied in patients that cannot be reached within a few hours from a nuclear reactor and to produce less radiation exposure to the medical personnel during the radiopharmaceutical administration.     

牛BMP注射型骨修复材料异位诱导成骨活性的研究

 目的 了解以纤维蛋白胶(Fibrin sealant,FS)为载体复合牛骨形态发生蛋白(bovine BMP,bBMP)的注射型骨修复材料异位诱导成骨的作用.方法 实验分为:实验组( FS+ bBMP)、对照组b(bBMP)、对照组FS (FS)和空白对照组.将各组材料注射或植入小鼠肌袋内,采用放射学检查、成骨量测定、碱性磷酸酶(Alkaline phosphatase,ALP)测定、组织形态学检查等方法对各组材料2周、4周异位诱导成骨进行研究.结果 (1)术后4周实验组及对照组b骨痂显影明显,对照组FS及空白对照组无骨痂形成;(2)术后4周,实验组的成骨量显著高于对照组、对照组FS和空白对照组(P＜0.01);(3)2周时各研究组ALP表达水平由高到低依次为:对照组b→实验组→对照组FS→空白对照组,有显著性差异(P＜0.01);4周时各研究组ALP表达水平由高到低依次为:实验组→对照组b→对照组FS→空白对照组,差异有显著性(P＜0.01). 结论以FS为载体复合bBMP的注射型骨修复材料具有高效的骨诱导活性.     

Nuclear medicine practice in Japan: a report of the sixth nationwide survey in 2007

Objective  The Subcommittee on the Survey of Nuclear Medicine Practice in Japan has performed a nationwide survey of nuclear medicine practice every 5 years since 1982 to provide detailed information on its present status. Methods  Questionnaires were sent to all institutions known to the Japan Radioisotope Association to conduct nuclear medicine examinations. The questionnaires addressed the number and kind of nuclear medicine examinations performed as well as the kind and dose of the radiopharmaceuticals used during the month of June 2007. The annual number of total or specific examinations was then estimated. Results  Of the institutions sent questionnaires, 1219 were for in vivo study, 49 for in vitro study, and 212 for positron emission tomography (PET) study. Of these, 92.2% provided answers. A total of 1569 gamma cameras were installed in 1119 institutions, of which 70% were dual-head cameras. The estimated total annual number of in vivo examinations expressed by the number of administered radiopharmaceuticals was 1.41 million, representing a decrease of 11.5% when compared with that of the previous survey (2002). The frequency of study with respect to single-photon emission computed tomography (SPECT) slightly increased to 42.3% from 39.9% in the previous survey. The most frequently performed scintigraphy was bone (38.3%), followed by myocardium (26.2%) and brain perfusion (14.1%). Brain perfusion scintigraphy slightly increased, whereas tumor scintigraphy decreased by one-half when compared with the previous survey. The most commonly used radiopharmaceutical for each scintigraphy was ^99mTc-HMDP for bone, thallium-201 (²⁰¹Tl)-chloride for myocardium, gallium-67 (⁶⁷Ga)-citrate for tumor, and technetium-99m-ethylcysteinate dimmer (^99mTc-ECD) for brain. The number of PET institutes increased from 36 to 212. ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG)-PET dramatically increased 14.8-fold during the past 5 years. Radionuclide therapy also increased. ¹³¹I therapy for thyroid cancer and hyperthyroidism was conducted yearly in 2373 and 4146 patients, respectively. A total of 13.1 million in vitro radioassays were carried out yearly, the number of which has been decreasing continuously since 1992. Conclusions  It was proved that the content of nuclear medicine practice in Japan has changed considerably in the past 5 years. Namely, ¹⁸F-FDG-PET and radionuclide therapy increased. This report might be useful for understanding the present trends of nuclear medicine practice in Japan.     

Radiation doses of yttrium-90 citrate and yttrium-90 EDTMP as determined via analogous yttrium-86 complexes and positron emission tomography

Yttrium-90 is used for palliative therapy for the treatment of skeletal metastases, but because it is a pure - emitter, data on the pharmacokinetics and radiation doses to metastases and unaffected organs are lacking. To obtain such data, the present study employed yttrium-86 as a substitute for⁹⁰Y, with detection by positron emission tomography (PET). The study compared the properties of two different⁸⁶Y complexes —⁸⁶y-citrate and⁸⁶Y -ethylene diamine tetramethylene phosphonate (EDTMP) — in ten patients with prostatic cancer who had developed multiple bone metastases (the ten patients being divided into two groups of five). Early dynamics were measured up to 1 h post injection (p.i.) over the liver region, followed by subsequent whole-body PET scans up to 3 days p.i. Absolute uptake data were determined for normal bone, bone metastases, liver and kidney. Radiation doses were calculated according to the MIRD recommendations. Based on the pharmacokinetic measurements of the distribution of the⁸⁶Y complexes, it was possible to calculate radiation doses for the bone metastases and the red bone marrow delivered by complexes containing⁹⁰Y. In 1 cm³ of bone metastasis, doses of 26±11 mGy/MBq and 18±2 mGy/MBq were determined per MBq of injected⁹⁰Y- citrate and⁹⁰Y- EDTMP, respectively. The doses to the bone marrow were 2.5±0.4 mGy/MBq for⁹⁰Y- citrate and 1.8±0.6 mGy/MBq for⁹⁰Y-EDTMP.⁸⁶Y and PET provide quantitative information applicable to the clinical use of⁹⁰Y. This method may also be useful for the design of other⁹⁰Y radiopharmaceuticals and for planning radiotherapy dosages.     

Nd:YAG激光照射大鼠皮肤组织的温度实验

目的验证激光与组织光热效应预示模型和计算结果，考查激光功率密度和照射时间与组织温度和损伤的定量关系，获得组织热效应的温度数据。方法连续Nd：YAG激光照射活体皮肤组织，组织为全身麻醉状态下大鼠腹部皮肤，每次实验同时测量三路信号：表面照射点辐射温度、皮下1mm的内部温度和环境温度。为了获得不同条件下的温度数据，根据照射功率和时间进行分组。结果得到连续Nd：YAG激光相同照射时间（t=1s）时不同功率（P=2、3、4、5w）、相同功率（P=5W）时不同照射时间（t=0．5、0．8、1．0s）以及照射功率较高时（t=0．5s，P=5、10、15w）的大鼠皮肤组织皮下1mm的温度。温度随着功率和照射时间的增加相应升高，温度响应形状相似，温度上升时间与照射时间相关。结论Nd：YAG激光表面辐射温度远远低于皮下温度，对热效应研究意义不大。热电偶所测内部温度能够很好地反映激光功率、照射时间的变化，可用来验证相关模型和数值模拟结果。     

Cortical bone mass in Nigerian children: an anthropometric assessment

Cortical bone mass was quantified in 1278 Nigerian children (695 males and 583 females) aged 3–16 years in a prospectively designed cross-sectional and longitudinal study. The total bone width (T) and medullary cavity width (M) were measured at the midshaft of the second metacarpal bone using a direct reading caliper. From the above measurements the cortical width (C), cortical area (CA), and percent cortical area (PCA) were calculated using the method of Garn et al. [6] and showed a progressive increase of T, C, CA and PCA, reaching a plateau at 15 years. At all ages, the values for both T and M are higher in males than in females. On the other hand, and contrary to established normal values amongst both white and black Americans, between the ages of 9 and 15 the female values for C are higher than those for males. This difference is greatest at the age of 12 years (p<0.001). The implication of this finding may be that during these years, African male children do not compensate for the increased endosteal resorption with a greater total cortical width (T), since the medullary width in females remains relatively constant over the years.