放射性125I粒子植入对人肺腺癌裸鼠移植瘤微血管生成的影响

目的 探讨放射性¹²⁵I粒子植入对人肺腺癌裸鼠移植瘤微血管生成的影响及其作用机制。方法 制备人肺腺癌细胞A549裸鼠皮下移植瘤模型24只,采用随机数字表法分为4组,每组6只,0、22.2、29.6 MBq组和对照组。用18 G植入针在各组裸鼠瘤体内分别植入放射活度为0、22.2和29.6 MBq ¹²⁵I粒子,每个移植瘤内植入一枚,对照组不予处理。观察肿瘤生长情况,每4天测量肿瘤大小。30 d后处死裸鼠,绘制肿瘤生长曲线。瘤组织免疫组织化学S-P法检测微血管密度（microvascular density,MVD）,并分别用RT-PCR、Western blot法检测血管内皮生长因子（vascular endothelial growth factor,VEGF）和缺氧诱导因子-1α（hypoxia inducible factor-1α,HIF-1α）的mRNA及蛋白的表达。结果 粒子植入治疗后54 d,22.2、29.6 MBq组移植瘤体积明显小于对照组（q=14.117、17.075,P<0.05）,但0 MBq组与对照组、22.2与29.6 MBq组瘤体积差异均无统计学意义（P>0.05）。CD34阳性染色结果显示,22.2 MBq组的MVD为522±119,29.6 MBq组为491±121,明显低于对照组的922±260（q=4.826、5.197,P<0.05）,但0 MBq组与对照组、22.2 MBq组与29.6 MBq组差异均无统计学意义（P>0.05）。RT-PCR检测表明,22.2 MBq组的VEGF和HIF-1α mRNA相对表达量分别为0.279±0.0659和0.370±0.0857,29.6 MBq组为0.215±0.0620、0.278±0.0651,均低于对照组（q=18.881、17.211和15.376、14.733,P<0.05）,但0 MBq组与对照组、22.2 MBq组与29.6 MBq组之间差异均无统计学意义（P>0.05）。Western blot结果显示,22.2 MBq组与29.6 MBq组瘤组织VEGF和HIF-1α蛋白表达均明显减少,与对照组相比,差异有统计学意义（q=5.848、6.263和6.560、7.576,P<0.05）,但0 MBq组与对照组以及22.2 MBq组与29.6 MBq组差异均无统计学意义（P>0.05）。结论 放射性¹²⁵I粒子植入能有效抑制人肺腺癌裸鼠移植瘤微血管生成。     

125I粒子抑制肝癌移植瘤血管形成的实验研究

目的 探讨放射性¹²⁵I粒子对肝癌裸鼠皮下移植瘤微血管形成的影响及其机制。方法 构建人肝癌Huh7细胞裸鼠皮下移植瘤模型,将12只裸鼠用随机数表法分为观察组和对照组,每组6只。观察组移植瘤植入一枚活度为2.96×10⁷Bq粒子,对照组植入一枚活度为0的空粒子。每4天测量1次移植瘤体积,记录肿瘤生长曲线。28 d后取下移植瘤,用免疫组织化学染色法检测CD31评估移植瘤微血管密度（MVD）。用免疫组织化学染色法检测血管内皮生长因子-A（VEGF-A）、缺氧诱导因子1α（HIF-1α）蛋白表达,并做半定量分析。用实时荧光定量聚合酶链反应（RT-PCR）检测VEGF-A、HIF-1α mRNA的表达。结果 观察组移植瘤的生长速度较对照组缓慢,粒子植入后12 d两组肿瘤体积差异有统计学意义（t=3.167,P<0.05）,随着观察时间延长,两组肿瘤体积差距加大,在28 d时两组肿瘤体积分别为（963.61±89.56）mm³和（602.10±75.98）mm³（t=7.122,P<0.05）。两组移植瘤组织中CD31均有表达,观察组的MVD较对照组少,差异有统计学意义（t=6.360,P<0.05）。观察组VEGF-A、HIF-1α mRNA及蛋白的表达水平均低于对照组,差异均有统计学意义（t=10.480、6.414、10.890、12.250,P<0.05）。结论 放射性¹²⁵I粒子通过降低肿瘤微血管密度抑制肝癌移植瘤的生长,其机制可能与VEGF-A、HIF-1α的mRNA及蛋白表达减少有关。     

153Sm-DTPA-c(CGRRAGGSC)对人MHCC97-H肝癌裸鼠模型的抑瘤作用

目的 探讨¹⁵³Sm-DTPA-c(CGRRAGGSC)对人MHCC97-H肝癌裸鼠模型移植瘤生长的抑制作用.方法 采用间接法合成¹⁵³Sm-DTPA-c(CGRRAGGSC)放射性药物.对8种不同细胞系IL-11受体表达,进行Western blot分析,选择肿瘤接种.20只MHCC97-H皮下荷瘤裸鼠按随机数字表法分为4组(对照组,低、中、高剂量组),每组5只.低、中、高剂量组尾静脉分别注入¹⁵³Sm-DTPA-c(CGRRAGGSC),剂量依序为5.5、11.0和22.0 MBq/0.2 ml,对照组尾静脉注入生理盐水0.2 ml.观察16 d后处死,比较肿瘤的体积,计算抑瘤率;观测标本病理改变;免疫组织化学检测5.5 MBq低剂量组瘤体组织治疗后Ki-67、Bcl-2和IL-11受体表达改变;Western blot检测不同剂量组IL-11受体的变化情况.结果 选择IL-11受体表达最高的MHCC97-H细胞接种.尾静脉内注射¹⁵³Sm-DTPA-c(CGRRAGGSC)后,早期瘤体中央可出现坏死、干瘪、结痂,后期又出现坏死周围瘤组织继续增长.低、中、高剂量组抑瘤率分别为(22.72±2.76)%、(34.65±2.36)%和(85.13±5.78)%(F＝89.32, P<0.05).免疫组织化学显示,对照组及低剂量组瘤内IL-11受体阳性率分别为(84.13±5.71)%和(61.57±5.98)%(t=13.62, P<0.05),低剂量组瘤细胞排列相对疏松,细胞内染色数量明显减少.低剂量组Ki-67、Bcl-2阳性率均较对照组下降(t=20.91、6.68, P<0.05).Western blot结果显示,随抑瘤作用增加,IL-11受体蛋白表达降低.结论 ¹⁵³Sm-DTPA-c(CGRRAGGSC)能够有效抑制人MHCC97-H肝癌裸鼠模型移植瘤的生长,促进IL-11受体表达下调及诱导凋亡作用.     

131I标记纳米脂质体靶向治疗结肠癌的实验研究

目的 研究¹³¹I-antiEGFR-BSA-PCL对LS180细胞结肠癌裸鼠移植瘤内照射的治疗效果。方法 构建抗表皮生长因子受体(EGFR)标记的纳米脂质体及EGFR靶向性。通过荧光共聚焦显微镜、细胞摄碘实验观察纳米载体的靶向性及LS180细胞对其摄取情况。将裸鼠40只按随机数字表法分为4组,通过瘤体内注射的方式向移植瘤内分别注射74 MBq (740 MBq/ml) ¹³¹I-antiEGFR-BSA-PCL、¹³¹I-BSA-PCL、¹³¹I及相同体积的生理盐水。通过研究裸鼠体重、肿瘤体积、SPECT显像及组织病理学方法,观察纳米脂质体的抑瘤效果。结果 共聚焦实验显示,与BSA-PCL组相比,antiEGFR-BSA-PCL组细胞内绿色荧光较明显,其介导的胞吞效应显著。摄碘率实验中,LS180细胞对¹³¹I-antiEGFR-BSA-PCL的摄取率明显高于¹³¹I-BSA-PCL(t=2.77~5.40,P<0.01)。¹³¹I-antiEGFR-BSA-PCL组与¹³¹I-BSA-PCL组裸鼠肿瘤增殖均较慢,二者差异无统计学意义(P>0.05)。给药后72 h,¹³¹I-antiEGFR-BSA-PCL与¹³¹I-BSA-PCL的肿瘤摄取率分别为(21.61±1.01)和(20.58±0.65)% ID/g,均明显高于¹³¹I组(t=9.36、8.69,P<0.01)。SPECT显像显示纳米脂质体主要特异性积聚在肿瘤区。结论 ¹³¹I-antiEGFR-BSA-PCL对LS180结肠癌裸鼠移植瘤有明显的抑制作用。     

携带125I粒子导管和徒手粒子植入模拟病灶后粒子纵向间距准确性的对比研究

目的 对比携带¹²⁵I粒子的可降解导管植入和徒手粒子植入后粒子纵向间距的准确性。方法 本研究用薯蓣制成24个模拟病灶,分为徒手组和粒子导管组,每组12个模拟病灶,由3位医师完成粒子和粒子针插植,每位医师每组插植4个病灶,每组共插植60针道,并按设定粒子间距（0.5和1.0 cm）分别在两组模拟病灶内行粒子植入。术后CT复查,并测量粒子纵向间距。配对t检验分析徒手组和导管组与设定间距偏离的差异。结果 徒手组与设定间距的偏离程度分别为（0.184±0.047）和（0.127±0.051）cm,导管组与设定间距的偏离程度分别为（0.007±0.006）和（-0.003±0.006）cm,导管组粒子的偏离程度明显小于徒手组（t=3.804、2.499,P<0.05）。结论 携带¹²⁵I粒子导管的应用,使粒子纵向间距的准确性优于徒手组,受术者的影响较小。     

Stattic抑制STAT3和HIF-1α途径对食管癌裸鼠移植瘤放射敏感性的影响

目的 探讨Stattic对食管癌ECA109细胞裸鼠移植瘤的放射增敏效果及其可能的作用机制。方法 建立食管癌ECA109细胞裸鼠移植瘤模型;移植瘤平均体积增至约150 mm³时,采用随机数表法将24只裸鼠分为4组,药物+照射组（25 mg/kg Stattic+6 Gy）、单纯药物组（25 mg/kg Stattic）、单纯照射组（6 Gy）、对照组,每组6只。25 d后测量移植瘤体积,计算肿瘤体积抑制率,Western blot法检测移植瘤组织中STAT3、缺氧诱导因子-1α（HIF-1α）及血管内皮生长因子（VEGF）蛋白的表达。结果 药物+照射组裸鼠移植瘤体积为（705.1±75.5）mm³,显著低于单纯照射组（1 113.5±101.4） mm³和单纯药物组（1 696.5±100.6）mm³（t=4.35、14.14,P<0.05）,其抑制率达（66.1±3.2）%。Western blot检测发现,药物+照射组移植瘤组织中pSTAT3、HIF-1α、VEGF蛋白表达水平较单纯照射组明显降低（t=17.07、5.05、3.54,P<0.05）。结论 Stattic对食管癌ECA109细胞裸鼠移植瘤具有放射增敏作用,可能与其抑制pSTAT3、HIF-1α、VEGF途径有关。     

慢病毒载体介导RNA干扰沉默Livin基因对大肠癌裸鼠移植瘤放射敏感性的影响

目的 探讨慢病毒载体介导RNA干扰沉默Livin基因表达,对大肠癌HT-29细胞裸鼠移植瘤生长及放射敏感性的影响。 方法 选取36只BALB/c(nu/nu)裸鼠,按随机区组法分为空白对照组、阴性对照组及实验组,将HT-29细胞接种于裸鼠,建立皮下移植瘤裸鼠模型,观察裸鼠体重及瘤体积的变化。RT-PCR、免疫组织化学分析Livin mRNA及蛋白表达的变化,原位末端标记法(TUNEL)法检测细胞凋亡的变化;瘤内注射生理盐水、空载慢病毒和干扰慢病毒,同时均给予10 Gy 6 MV X射线照射,绘制裸鼠体重和移植瘤生长曲线。结果 实验组体积抑瘤率为(50.04±0.07)%,瘤体重量明显减轻(F=4.85,P<0.05), 瘤重抑瘤率为(50.27±0.17)%。实验组Livin mRNA表达水平为(17.75±0.08)%,明显低于空白对照组的(67.60±0.05)%和阴性对照组的(68.54±0.03)% (F=89.97, P<0.01)。实验组Livin蛋白表达水平为(36.00±3.40)%,明显低于空白对照组的(85.00±3.15)%和阴性对照组的(80.33±3.08)%(F=107.32,P<0.01)。实验组凋亡率为(23.67±2.25)%,明显高于空白对照组的(5.00±1.50)%和阴性对照组的(8.33±1.82)%(F=56.94,P<0.01)。与射线联合时,裸鼠移植瘤体积在分组之间总体存在差异(F=10.70,P<0.01),实验组肿瘤体积变化小于阴性对照组和空白对照组(F=7.01~9.32,P<0.01)。结论 慢病毒载体介导RNA干扰沉默Livin基因表达能抑制大肠癌HT-29细胞裸鼠移植瘤的生长,并增加移植瘤对放疗的敏感性。     

177Lu-FA-DOTA-PEG-PLGA靶向可降解纳米粒子腹腔灌注治疗小鼠卵巢癌伴腹膜转移的实验研究

目的 观察放射性核素¹⁷⁷Lu标记的叶酸-二乙烯三胺五乙酸-聚乙二醇-聚乳酸共聚物(¹⁷⁷Lu-FA-DOTA-PEG-PLGA)纳米粒子的体内靶向分布,评价腹腔灌注纳米粒子治疗小鼠卵巢癌腹膜转移瘤及腹水疗效。方法 制备¹⁷⁷Lu-FA-DOTA-PEG-PLGA纳米粒子,向人卵巢癌移植瘤荷瘤小鼠尾静脉注射纳米粒子后4、24、72 h和7 d,行微型单光子发射计算机断层显像仪(micro-SPECT/CT)显像,观察纳米粒子体内分布情况。将12只人卵巢癌腹腔转移瘤裸鼠模型按随机抽签法分为阴性对照组(生理盐水)、化疗组(顺铂3 mg/kg,2次/周)和粒子组(¹⁷⁷Lu-FA-DOTA-PEG-PLGA粒子18.5 MBq),每组4只,腹腔灌注给药。7 d后行活体荧光成像评价腹腔肿瘤生长情况,计算相对抑瘤率,TUNEL法检测肿瘤细胞凋亡率,免疫组织化学法检测肿瘤Ki67增殖活性,比较治疗后各组腹水体积。结果 micro-SPECT/CT显像显示,移植瘤放射性浓聚,24 h肿瘤肌肉摄取比值(T/M)最高,为2.81±0.49。活体荧光成像显示,腹腔给药治疗后,粒子组、化疗组和阴性对照组的腹腔肿瘤荧光强度分别为(1.45±0.19)×10¹⁰、(2.21±0.36)×10¹⁰和(2.63±0.79)×10¹⁰,差异有统计学意义(F=6.09,P=0.029);粒子组和化疗组的相对肿瘤抑制率(TGI)分别为35.6%和18.6%。粒子组和化疗组的肿瘤细胞凋亡率(AI)均高于阴性对照组(F=9.96,P=0.009),粒子组和化疗组的Ki67指数均低于阴性对照组(F=9.93,P=0.013),粒子组和化疗组腹水体积均小于阴性对照组(F=13.43,P=0.006)。结论 ¹⁷⁷Lu-FA-DOTA-PEG-PLGA纳米粒子可行小鼠卵巢癌靶向显像,腹腔灌注后局部滞留和降解吸收,抑制卵巢癌腹膜转移瘤和腹水生长,为晚期卵巢癌伴腹膜转移患者诊疗提供新思路。     

雷帕霉素激活M2巨噬细胞自噬影响大肠癌放射敏感性的研究

目的 探讨雷帕霉素(RAP)激活M2巨噬细胞(type-Ⅱ macrophage)自噬对大肠癌移植瘤放射敏感性的影响。方法 经佛波酯(PMA)单独及联合人重组白介素4(IL-4)诱导人单核白血病细胞THP-1分化为M0和M2型巨噬细胞。使用RAP激活M2自噬,设置巴弗洛霉素(bafilomycin A1)下调M2已被激活的自噬作为对照。将大肠癌LoVo细胞接种于BALB/c-nu/nu裸鼠,待形成直径10 mm瘤体后,利用随机数表法,将18只裸鼠分为M2自噬未激活组、激活组和激活后下调组,LoVo细胞单独成瘤为阴性对照组,每组6只。对荷瘤鼠行2次8 Gy X射线局部照射,分析各组间移植瘤放射敏感性的变化。结果 M2巨噬细胞标志物Arg-1、CCL-22的相对表达量显著高于M0巨噬细胞(t=78.77、60.02,P＜0.05)。M2自噬未激活组瘤体质量、体积和微血管密度(MVD)[(1.93±0.05)g、(2.14±0.06) cm³、36.37±1.04]较阴性对照组[(1.35±0.05) g、(1.77±0.02) cm³、25.69±1.34]显著提高(t=20.07、14.56、10.92,P＜0.05);激活M2自噬后,瘤体重量、体积和微血管密度均显著下降[(0.89±0.03) g、(1.24±0.01) cm³、13.60±1.52](t=44.37、40.32、21.43,P＜0.05)。利用巴弗洛霉素下调M2自噬后,瘤体质量、体积和微血管密度有所回升[(1.02±0.07) g、(1.37±0.02) cm³、21.06±1.41](t=4.67、13.79、6.23,P＜0.05)。与阴性对照组相比,自噬未激活的M2能够抑制Livin和Survivin在瘤体组织中的表达(t=2.64、7.90,P＜0.05);RAP激活M2自噬后,可进一步下调上述蛋白的表达(t=5.43、9.39,P＜0.05)。利用巴弗洛霉素下调M2自噬后,Livin、Survivin表达量均有所回升(t=2.80、3.17,P＜0.05)。结论 利用RAP激活M2自噬,可抑制M2促进肿瘤微血管形成的能力,从而抑制移植瘤生长;同时,通过下调大肠癌移植瘤中抗凋亡基因Livin与Survivin的表达,诱导大肠癌移植瘤放疗后凋亡的发生,提高大肠癌的放射敏感性。     

共面模板辅助CT引导下125I粒子植入治疗脊柱转移瘤疗效分析

目的 探讨共面模板（co-planar template, CPT）辅助CT下植入¹²⁵I放射性粒子近距离治疗脊柱转移瘤质量控制与近期疗效。方法 12例原发肿瘤经病理学明确诊断,影像学改变符合脊柱转移瘤特征,患者共有16个病灶。处方剂量（prescribed dose, PD）80 Gy,粒子活度（1.48×10⁷~2.59×10⁷）Bq（0.4~0.7 mCi）,CPT辅助CT引导下将植入针按术前计划穿刺并种植放射性¹²⁵I粒子。术后即刻扫描观察粒子分布情况,剂量评估。随访复查CT判定瘤体直径变化,进行疗效评估。随访时间为3~29个月。同时给予疼痛分级,评判疼痛改善情况。结果 16个病灶全部穿刺成功植入粒子。植入后剂量验证显示肿瘤靶区接受的平均照射剂量（209.21±37.16）Gy,D₉₀为（115.29±7.87）Gy,D₁₀₀为（76.59±5.53）Gy,V₉₀为（99.30±0.51）%,V₁₀₀为（98.06±1.15）%,适形指数（CI）0.981±0.012,靶区外体积指数（EI）0.012±0.007。脊髓接受的平均照射剂量为（30.47±4.83）Gy。靶区和脊髓接受的平均照射剂量与术前计划比较,差异无统计学意义（P>0.05）。术后3个月病灶完全缓解（CR）18.8%（3/16）, 部分缓解（PR）62.5%（10/16）,疾病进展（PD）6.25%（1/16）,疾病稳定 （SD）6.25%（1/16）,有效率（CR+PR）81.3%;疼痛完全缓解3例,部分缓解7例,轻度缓解2例;生存期11~39个月,中位生存期24个月。所有患者脊髓无放射性损伤发生。结论 应用CPT辅助CT引导可以按照术前计划控制粒子植入的位置和放射剂量,达到治疗肿瘤、并发症少、患者可耐受的目的。     

人体中的镭-226、镭-228、钋-210、铅-210

本文报道了广东阳江高本底地区6名、对照地区8名人尸体的骨²²⁶Ra、²²⁶Ra的浓度以及部分居民内脏器官中。²¹⁰Po、²¹⁰Pb的浓度。结果轰明阳江高本底地区和对照地区居民骨镭-226、镭-228的浓度分别为29.9pCi/kg, 26.9pCi/kgl 8.7pCi/kg, 8.2pCi/kg.由此估算出阳江高本底地区屠民骨中²²⁶Ra、²²⁸Ra的负薄璧及对骨衬、骨髓所产生的剂量当量分别为对照地区民民的3.4倍, 3.3倍。两地区居民内脏器官中^{210Po、210Pb的测定分析铡数较少但仍看出, 高本底地区均明显高于对照地区.}     

Production of large quantities of 90Y by ion-exchange chromatography using an organic resin and a chelating agent

The performance of a system composed of an organic cation exchanger (Dowex 50Wx8) and a chelating agent (EDTA) previously described for the successful production of (90)Y via a (90)Sr/(90)Y generator is assessed under dynamic conditions. In an attempt to overcome the established limitation of ion-exchange resins for the separation of subcurie quantities of activity, (90)Y is repeatedly isolated from an 11.8-GBq (320 mCi) (90)Sr cow using a three-column tandem arrangement. The high recovery and radionuclidic purity obtained for (90)Y and the parameters of the separation (time, eluant concentration, pH and flow rate range) strongly suggest that Ci quantities of (90)Y can be handled satisfactorily by the ion-exchange method. No replacement or treatment of the cow, low waste generation and (90)Sr losses less than 0.1% after each run were observed during the present study which, in combination with the low cost of this resin, may result in an attractive alternate method for the production of large quantities of (90)Y.     

Comparison of extraarticular leakage values of radiopharmaceuticals used for radionuclide synovectomy

OBJECTIVES: Radionuclide synovectomy is a reliable therapy in patients with chronic synovitis. However, radiation doses delivered to non-target organ systems due to leakage of radioactive material from the articular cavity are an important disadvantage of this procedure. In this study we compared extraarticular leakage values of the 3 commonly used radiopharmaceuticals; 90Y-citrate, 90Y-silicate and 186Re-sulfide colloid. MATERIALS AND METHODS: Thirty-five patients with persistent synovitis were enrolled in the study. Twenty-two hemophilic, 8 rheumatoid arthritis and 5 patients with pigmented villonodular synovitis were studied. 90Y labeled silicate and citrate were used for knee joints and 186Re-sulfide for intermediate sized joints. Radiocolloid leakage values were evaluated using a gamma camera with 20% window centered over the bremsstrahlung photopeak of 90Y and a respective window over the 137 keV photopeak of 186Re. Regions of interest were drawn over the injection site, the regional lymph nodes and the background areas. Leakage of radiocolloid was calculated by dividing the counts/pixel in the regional lymph node area to the counts/pixel in the injection site. RESULTS: No visible leakage was observed. The median leakage values calculated for 90Y-citrate, 90Y-silicate and 186Re-sulfide were found as 1.9%, 2.4% and 2.7%, respectively. The difference between the variability of leakage values was not statistically significant (p > 0.05). CONCLUSION: There was no significant difference in terms of extraarticular leakage between 9Y-citrate, 9Y-silicate and 186Re-sulfide radiocolloids.     

Rapid determination of Sr impurities in freshly “generator eluted” Y for radiopharmaceutical preparation

⁹⁰Y is one of the most useful radionuclides for radioimmunotherapeutic applications and has a half-life (t_1/2=64.14 h) suitable for most therapeutic applications, beta particles of high energy and decays to a stable daughter. It is significant that ⁹⁰Y is available conveniently and inexpensively from a radionuclide “generator” by decay of its parent, ⁹⁰Sr. Nevertheless, current and planned clinical applications with [⁹⁰Y] labelled compounds employ activity levels that cannot be readily obtained from an in-house generator, but from commercial sources. We have evaluated Eichrom's Sr-resin, either as an “in-house” generator or as a fast QC method for analysis of ⁹⁰Y solutions.In particular, for the development as a generator, we investigated the percentage of the radio-Sr in the first 8 M HNO₃ eluate: in this fraction the concentration of ⁹⁰Sr must be smaller than 10⁻⁵% (recommendations of the International Commission on Radiological Protection). For evaluation as a rapid QC method, we analyzed the concentration of ⁹⁰Y in all the fractions containing “only” radio-Sr: ⁹⁰Y should not be present in these eluates. After the collection of β⁻ and γ spectra and analysis of them, we concluded that commercial Sr-resin minicolumn cannot give us the results expected; we developed an in-house system loaded with 4 mL of Sr-resin which gave better results as a generator and a rapid QC method.     

Radiobiological Issues in the Anomalous Enhanced Effect of Low-dose-rate Fission-spectrum Neutrons: Reply to Letter to the Editor by G. W. Barendsen

Summary

The influence of diet or its ingredients on ¹⁴¹Ce absorption and retention was investigated in six-day-old rats. Animals were fed over 8 h with cow's milk, rat diet or a mixture of rat diet ingredients (fish meal, sunfiower meal, alfalfa, cane molasses and premix) labelled with ¹⁴¹Ce. Whole-body radioactivity was determined in a double crystal scintillation counter every 24 h over a six-day period. Gut, liver, kidney and femur retention and cerium distribution in the gut was determined at the end of the experiment. Compared to milk diet, administration of rat diet or ingredients caused respectively 3 and 7·5 times lower whole body retention. Carcass retention was reduced by rat diet or ingredients 2–3 times and intestinal retention 3 and 8 times respectively. Irrespective of the dietary treatment the main site of cerium intestinal retention was the ileum. Our present results indicate that some compounds of rat diet might be considered as a means of reducing cerium absorption and intestinal retention in the very young.     

226Ra 228Ra 210Pb和210Po在水生生物及食物链中转移规律的探讨

目的 为了解天然放射性核素²²⁶Ra、²²⁸Ra、²¹⁰Pb与²¹⁰Po在水生物及食物链中转移和蓄积情况。方法 定点采集养殖水产品及栖息环境中水与底质沉积物, 按不同的实验需要, 每个鲜样分别剥取肉, 骨(壳),鳞片和胃肠。烹饪样品, 洗净、称重、清炖, 熟后分离出骨(壳),余为食物。样品分别测定²²⁶Ra、²²⁸Ra、²¹⁰Pb和²¹⁰Po含量。数据按统计学要求处理, 配对数据, 作了配对显着性检验。结果 ²²⁶Ra、²²⁸Ra和²¹⁰Pb主要沉积于骨(壳)中, 浓集系数为10²～10³,肉中为10⁰～10².²¹⁰Po主要蓄积在水生物胃肠中, 浓集系数在10²～10⁴,鱼类胃肠与贝类肉中可达10⁴.水产食品烹饪加工过程²²⁶Ra、²²⁸Ra和²¹⁰Pb在食物链中转移不明显, 经配对显着性检验, 差异无显着性(P0.05);然而210Po在淡水鱼类和虾类中转移是明显的, 肉配对检验有非常显着性差别(P<0.01).结论水生物对²²⁶Ra、²²⁸Ra、²¹⁰Pb和²¹⁰Po有很强浓集能力。     

Rapid synthesis and in vitro and in vivo evaluation of folic acid derivatives labeled with fluorine-18 for PET imaging of folate receptor-positive tumors

In an attempt to visualize folate receptors that overexpress on many cancers, [¹⁸F]-fluorobenzene and pyridinecarbohydrazide-folate/methotrexate conjugates ([¹⁸F]-1, [¹⁸F]-2-folates and [¹⁸F]-8, [¹⁸F]-9-MTXs) were synthesized by the nucleophilic displacement reactions using ethyl-trimethylammonium-benzoate and pyridinecarboxylate precursors. The intermediates ethyl [¹⁸F]-fluorinated benzene and pyridine esters were reacted with hydrazine to produce the [¹⁸F]-fluorobenzene and pyridinecarbohydrazides, followed by coupling with N-hydroxysuccinimide-folate/MTX. Radiochemical yields were greater than 80% (decay corrected), with total synthesis time of less than 45 min. Radiochemical purities were always greater than 97% without high-performance liquid chromatography purification. These synthetic approaches hold considerable promise as rapid and simple method for the radiofluorination of folate derivatives with high radiochemical yield in short synthesis time. In vitro tests on KB cell line showed that significant amount of the radioconjugates were associated with cell fractions, and in vivo characterization in normal Balb/c mice revealed rapid blood clearance of these radioconjugates with excretion predominantly by the urinary and partially by the hepatobiliary systems. Biodistribution studies in nude mice bearing human KB cell line xenografts demonstrated significant tumor uptake and favorable biodistribution profile for [¹⁸F]-2-folate over the other conjugates. The uptake in the tumors was blocked by excess coinjection of folic acid, suggesting a receptor-mediated process. Micro-positron emission tomography images of nude mice bearing human KB cell line xenografts confirmed these observations. These results demonstrate that [¹⁸F]-2-folate may be useful as molecular probe for detecting and staging of folate receptor-positive cancers, such as ovarian cancer and their metastasis as well as monitoring tumor response to treatment.     

Scintigraphic findings of MALT lymphoma of the thyroid

Mucosa-associated lymphoid tissue (MALT) lymphoma has been established as a distinct entity among non-Hodgkin's lymphomas, and the most common primary site is the stomach. We describe scintigraphic findings in a patient with MALT lymphoma of the thyroid. A 71-year-old woman with Hashimoto's thyroiditis suffered from rapid cervical swelling, and ultrasonography and CT revealed a thyroid nodule. The nodule showed accumulation of 99mTc pertechnetate comparable to the surrounding thyroid tissue, mimicking a benign nodule. Both 67Ga and 201Tl imaging visualized the lesion as an increased uptake area. After radiotherapy, abnormally increased uptake disappeared on 67Ga images, which predicted a favorable outcome. MALT lymphoma of the thyroid may be visualized as a warm nodule on 99mTc pertechnetate scintigraphy.     

Development of a modular system for the synthesis of PET [C]labelled radiopharmaceuticals

[¹¹C]labelled radiopharmaceuticals as N-[¹¹C]methyl-choline ([¹¹C]choline), l-(S-methyl-[¹¹C])methionine ([¹¹C]methionine) and [¹¹C]acetate have gained increasing importance in clinical PET and for the routine production of these radiopharmaceuticals, simple and reliable modules are needed to produce clinically relevant radioactivity. On the other hand, flexible devices are needed not only for the routine synthesis but also for more complex applications as the development of new tracers. The aim of this work was the adaptation of an Eckert Ziegler modular system for easy routine synthesis of [¹¹C]choline, [¹¹C]methionine and [¹¹C]acetate using components that account for straightforward scaling up and upgrades.     

The role of I-131-MIBG in the diagnosis and therapy of carcinoids

The successful use of ¹³¹I-MIBG for the diagnosis and treatment of pheochromocytoma and neuroblastoma has led to its application in patients with carcinoid, another neural crest tumor. The present report describes the scintigraphic findings, in correlation with clinical and biochemical parameters, in 20 patients with histologically proven carcinoids. ¹³¹I-MIBG total body scintigraphy was positive in 12 and equivocal in 1 of 19 patients with metastases. The necessity of delayed imaging and the possible advantage of single photon emission tomography for the detection of this tumor are emphasized. The results of ¹³¹I-MIBG treatment in five patients with progressive carcinoid metastases are discussed. It is concluded that ¹³¹I-MIBG has a role in the work up of patients with proven carcinoid and can be used for palliative treatment of this tumor.