新型脑显像剂 99TcmN(CHDTC)2的兔血药 清除动力学及猴脑显像初步研究

目的　对一种新型脑显像剂 99TcmN(CHDTC) 2 进行临床前兔血药清除动力学、猴脑显像研究 ,以观其有无进一步临床研究的价值。方法　将用配体交换法制备的 99TcmN (CHDTC) 2 进行兔血药清除动力学、猴脑显像研究。结果　将放化纯大于 90 %的 99TcmN(CHDTC) 2 给兔静脉注射后其清除半衰期 =8.70h ;清除率 =5 2 9.5ml/h。猴脑血流显像提示 ,注药后颅内放射性逐渐升高 ,至 1h行脑SPECT显像 ,脑灰白质显像基本清楚。提示显像剂可进入血脑屏障 ,并在脑实质有较好滞留。结论　 99TcmN(CHDTC) 2 是一种有潜力的新型脑显像剂 ,值得进行临床研究。     

99Tcm-octreotide在荷H22肝癌小鼠体内分布和显像研究

目的探讨99Tcmoctreotide作为生长抑素受体阳性肿瘤显像剂的可能性。方法99Tcmoctreotide的制备采用直接标记奥曲肽冻干品药盒的方法。①体内分布实验:25只正常KM小鼠和15只荷H22肝癌小鼠,静脉注射显像剂0.1ml(3.7MBq)后行常规体内分布实验,计算%ID/g及肿瘤的T/NT值。②荷瘤鼠显像:5只荷瘤鼠于注入显像剂后1、2、3、4、6h和24h不同时相分别显像并计算T/B值。结果①体内分布:正常小鼠体内分布显示,血液在0.5h放射性最高[(3.20±0.54)%ID/g],随后迅速清除。双肾1h摄取达最高[(13.62±4.83)%ID/g],提示显像剂主要经泌尿系统排泄。99Tcmoctreotide在荷瘤鼠的体内分布与正常小鼠一致,肿瘤与其他脏器组织的T/NT较高。②受体显像:注射显像剂1h后,小鼠全身轮廓清晰,肾和膀胱高度摄取显像剂,荷瘤鼠的已知肿瘤部位呈阳性显像。在2h肿瘤部位的放射性浓聚最高,显像效果最佳。随后放射性逐渐减弱,但肿瘤影像仍较清晰。24h时图像模糊。注射显像剂后1、2、3、4、6h和24h的T/B值分别为2.64、4.46、7.25、5.40、5.49和6.48,2h以后各时相与1h相比有显著性差异(P<0.05),但3h以后与前一时间点比较差异均无显著性(P>0.05)。结论一步法药盒制备的99Tcmoctreotide,在小鼠H22肝癌组织中分布快,消除较慢,靶和本底比值较高,注射后2h肿瘤显像最佳。99Tcmoctreotide是一种很有前景的生长抑素受体显像剂。     

荷瘤小鼠肿瘤细胞凋亡显像的实验研究

目的研究细胞凋亡显像剂99Tcm-HYNIC-Annexin Ⅴ的制备及其在荷瘤小鼠体内的生物分布特性和活体显像.方法采用双功能螯合剂HYNIC法锝[99Tcm]标记Annexin Ⅴ,经高效液相色谱仪分离纯化并检测标记产物.建立荷肿瘤小鼠模型,在20～25 g昆明种小白鼠右前腋下皮下接种S-180肉瘤,生长1周.荷瘤小鼠在环磷酰胺腹腔内给药化疗72 h后,尾静脉注射99Tcm-HYNIC-Annexin Ⅴ,分别于5 min、30 min、1 h、3 h、6 h后进行SPECT显像和体内生物分布测定.实验结果应用SPSS 12.0统计学软件进行统计学分析.结果 99Tcm-HYNIC-Annexin Ⅴ的标记率达到95%,放射性化学纯度为99%.荷瘤小鼠在环磷酰胺腹腔内给药化疗后72 h显像可见:注射99Tcm-HYNIC-Annexin Ⅴ后6 h肿瘤组织呈明显异常放射性浓聚灶.体内生物分布实验观察到,注射显像剂后6 h肿瘤组织的放射性摄取值(1.59±0.44)最高,与其他时相的肿瘤组织放射性摄取值比较P<0.05. 99Tcm-HYNIC-Annexin Ⅴ主要聚集在肾脏、肺脏和肝脏等,从肾脏排泄,其血流清除速度快,在注射后30 min,血液放射性摄取值(1.59±0.50)仅为5 min时(8.85±2.65)的20%(P<0.05).注射显像剂后6 h,肿瘤/肌肉放射性摄取率比值(3.73±1.42)高于肿瘤/血液放射性摄取率比值(2.80±0.54).结论 99Tcm-HYNIC-Annexin V有望成为一种富有应用前景的活体细胞凋亡分子探针.     

单次化疗后荷瘤小鼠肿瘤细胞凋亡显像研究

目的探讨活体肿瘤细胞凋亡监测作为评价肿瘤对化疗反应的一种新方法的可行性.方法细胞凋亡分子探针99Tcm-HYNIC-Annexin Ⅴ经化学和放射化学合成获得.20～25 g昆明种小白鼠右前腋下皮下组织接种S-180肉瘤,建立荷肿瘤小鼠模型.荷瘤小鼠在环磷酰胺腹腔内给药化疗8 h、24 h、48 h、72 h后,分别尾静脉注射99Tcm-HYNIC-Annexin Ⅴ,1 h后进行单光子发射型计算机断层显像(SPECT)和体内生物分布测定,并与对照组进行比较.根据化疗后显像的最佳时间,给荷瘤小鼠尾静脉注射99Tcm-DTPA-HSA,测定体内各组织器官的血流分布情况.所有体内生物分布的实验结果应用SPSS 10.0统计学软件进行统计学分析.结果荷瘤小鼠在环磷酰胺腹腔内给药化疗后72 h进行SPECT显像时,肿瘤的显像效果最明显,且体内生物分布测定显示在化疗后72 h的肿瘤组织的放射性摄取值(1.87±0.58)最高,是对照组(1.18±0.128)的1.58倍(二者比较,P<0.05),与显像结果具有一致性.肿瘤/肌肉(T/M)放射性摄取率之比为5.83±0.799,肿瘤/血液(T/B)为1.03±0.258,与对照组比较均为P<0.05.化疗组和对照组的肿瘤组织对99Tcm-DTPA-HSA的摄取无明显差异(P>0.05).结论在进行单次环磷酰胺腹腔内给药化疗后72 h,荷瘤小鼠的肿瘤组织对 99Tcm-HYNIC-Annexin Ⅴ的摄取显著增加,细胞凋亡体内显像作为一种评价肿瘤对化疗反应的无创性的监测方法是有效、可行的.     

环形精氨酸-甘氨酸-天冬氨酸多肽的核素标记及在健康动物体内的实验

目的:探讨99Tcm直接标记环形RGD-4CK九肽的可行性,观察99Tcm-RGD-4CK在健康动物体内的药代动力学、生物分布特点及显像表现。方法:实验于2004-10/2005-11在解放军第三军医大学西南医院核医学中心完成。①采用预锡化法99Tcm直接标记RGD-4CK,3MM色谱纸层析测定标记率,通过HPLC分析、SepPakC18柱层析、体外稳定性实验、半胱氨酸置换实验及血清蛋白结合实验,评价99Tcm-RGD-4CK的放射化学性质。②选取雄性日本大耳兔9只,每只静脉注射37MBq99Tcm-RGD-4CK,分别于1.5,3.0,5.0,10,30,60,90,120,180,240min采血、称重并测定血样品放射性计数,结果经参考源校正后以MBq/L表示,所得数据应用DAS软件处理,结合αvβ3受体在正常体内实际表达情况判断室模型。③选取小鼠40只,随机分为8组(n=5),每只静脉注射0.74MBq99Tcm-RGD-4CK,分别于1,5,20,60,90,120,180,240min处死小鼠,采集血液、心、肺、肝、肾、肠、肌肉、骨、脑,称重并测定放射性计数,结果经参考源校正后以每克组织百分注入剂量(%ID/g)表示。④选取雄性日本大耳兔3只,每只静脉注射37MBq99Tcm-RGD-4CK,应用SPECT进行显像,结合感兴趣时间-放射性曲线分析,观察家兔体内放射性的动态分布变化。结果:40只小鼠和12只兔全部进入结果分析。①99Tcm-RGD-4CK标记率为(97.8±0.4)%,比活度为(11.90±0.05)PBq/mol;HPLC保留时间与洗脱液放射峰值时间基本一致,室温放置6h的放射化学纯度仍>95%;SepPakC18柱层析游离99Tcm仅比纸层析高0.5%;与300mmol/L半胱氨酸37℃温育1h,游离99Tcm仅增加1.88%;99Tcm-RGD-4CK与血清蛋白无明显结合。②99Tcm-RGD-4CK在健康家兔体内的药代动力学符合权重数为1/C的二室模型,分布相半衰期为(4.18±2.17)min,消除相半衰期为(69.32±0.00)min。③小鼠血液放射性清除迅速,通过肾脏排泄且快,其余组织器官放射性均随时间逐渐降低,而脑始终呈最低放射水平。④家兔SPECT显像示:各组织器官T-A曲线均随时间逐渐下降,与肾、心、肝相比,肺、胃、肌肉曲线呈低水平;1min双肾即显影,5min心、肝影开始减弱,肺放射性分布均匀,强度低于肝脏,膀胱显影;5min后膀胱影持续增强,20min后软组织影逐渐减弱;胆囊未显影,腹部呈持续低放射分布,胃区始终呈放射性缺损,颈部未见明显核素浓聚。结论:99Tcm-RGD-4CK制备方法简便,标记率高(>95%),具有良好的放射化学性质,体内稳定性好,具有比较理想的体内动力学。     

奥曲肽定位诊断肝癌的实验研究

目的探讨和评价放射性同位素标记奥曲肽（^99mTc-HTOC）在肝癌荷瘤鼠中的组织分布及肿瘤摄取率。方法对肝癌荷瘤鼠先后进行^99mTc-奥曲肽^99mTc-HTOC）全身显像，并观察奥曲肽（Octreotide）在肿瘤组织和其他正常组织器官的组织分布情况。结果放射性核素^99mTc标记奥曲肽（Octreotide）后的放化纯度均〉95％：在肿瘤组织中有良好的组织摄取率，在体外，^99mTc-HTOC与SSTR。有高的亲和力（kd为1-2.5nmol／L），并迅速进入SSTR；阳性的细胞。在荷瘤小鼠的研究中，肿瘤细胞高度摄取^99mTc-HTOC给药后4h为9.7％ID／g，而肾脏滞留较低。结论^99mTc-HTOC对荷瘤鼠摄像以了解放射标记奥曲肽在肿瘤及其重要器官的摄取情况，为肝癌的靶向治疗提供生物学依据。     

131I标记RGD环肽在荷瘤小鼠体内分布与显像研究

目的 研究131I标记含精氨酸-甘氨酸-天冬氨酸的小分子环形肽(cRGD肽)在荷瘤小鼠体内的分布与显像,探讨131I-cRGD肽作为肿瘤诊治药物的可能性.方法 利用氯胺T法对cRGD肽行131I标记,建立荷黑色素瘤B16动物模型,分别进行体内分布实验、非标记cRGD肽竞争抑制实验及肿瘤显像研究.结果用统计软件SPSS 12.0进行分析.结果 131I-cRGD肽的标记率达90%,放射化学纯度达99%;荷瘤小鼠体内分布实验显示给药后在血液、肾脏、膀胱有较高的放射性分布,小肠、肝脏、肌肉呈低水平放射性分布,24 h 肿瘤/肌肉(T/M)放射性比值=6.34, 肿瘤/血液(T/B)放射性比值=1.1.显像结果示静脉注射131I-cRGD肽后1 h肿瘤开始显影,随时间的延长,影像逐渐清晰,24 h时肿瘤显像最清晰.用非标记cRGD肽进行阻断实验,肿瘤的放射性摄取为(0.969±0.151)%/g,与非阻断组(1.40±0.136)%/g比较具有显著性差异.结论 应用氯胺T法可以成功完成131I-cRGD肽标记;尾静脉注射131I-cRGD肽后,肿瘤表现为放射性浓聚,肿瘤对131I-cRGD肽的摄取可被非标记的cRGD肽抑制,表明131I-cRGD肽可与肿瘤新生血管αvβ3受体特异性结合,有望成为一种新型的肿瘤诊治药物.     

99mTc-K237的制备及其在小鼠体内分布和显像

目的 探索99mTc标记多肽K237的方法 ,研究标记物的稳定性及其在小鼠体内的分布.方法 采用99mTc直接标记多肽K237.正常小鼠尾静脉注射99mTc-K237后不同时间处死,取血液及主要脏器,测定其每克组织百分注射剂量率(%ID/g).经尾静脉将99mTc-K237注入荷人肺癌A549裸鼠,于注射后不同时间显像.结果 99mTc-K237的标记率和放化纯均＞95%,其与人脐静脉内皮细胞(HUVEC)的最高特异性结合率为40.36%.99mTc-K237在生理盐水和正常人血清中放置24 h后,其放化纯分别为(89.1±1.4)%和(88.3±1.1)% (t=1.56,P＞0.05).静脉注射99mTc-K237后24 h内,小鼠血液放射性清除迅速,放射性主要聚集在肾脏并经其清除,其他组织器官的放射性随时间逐渐降低.99mTc-K237荷人肺癌A549裸鼠显像示肿瘤组织摄取高,肿瘤与对侧正常组织放射性计数比值(T/NT)最高可达3.97±0.31.结论 99mTc-K237易于制备,具有较理想且符合实际的动物体内动力学表现.     

环形精氨酸-甘氨酸-天冬氨酸多肽的核素标记及在健康动物体内的实验

目的：探讨^99Tc^m直接标记环形RGD-4CK九肽的可行性，观察^99Tc^m-RGD-4CK在健康动物体内的药代动力学、生物分布特点及显像表现。 方法：实验于2004—10／2005-11在解放军第三军医大学西南医院核医学中心完成。①采用预锡化法^99Tc^m直接标记RGD-4CK，3MM色谱纸层析测定标记率，通过HPLC分析、SepPakC18柱层析、体外稳定性实验、半胱氨酸置换实验及血清蛋白结合实验，评价^99Tc^m-RGD-4CK的放射化学性质。②选取雄性日本大耳兔9只，每只静脉注射37MBq^99Tc^m-RGD-4CK，分别于1．5，3．0，5．0，10，30，60，90，120，180，240min采血、称重并测定血样品放射性计数，结果经参考源校正后以MBq／L表示，所得数据应用DAS软件处理，结合α，β3受体在正常体内实际表达情况判断室模型。③选取小鼠40只，随机分为8组（n=5），每只静脉注射0．74MBq^99Tc^m—RGD-4CK，分别于1，5，20，60，90，120，180，240min处死小鼠，采集血液、心、肺、肝、肾、肠、肌肉、骨、脑，称重并测定放射性计数，结果经参考源校正后以每克组织百分注入剂量（％ID／g）表示。④选取雄性日本大耳兔3只，每只静脉注射37MBq^99Tc^m-RGD-4CK，应用SPECT进行显像，结合感兴趣时间-放射性曲线分析，观察家兔体内放射性的动态分布变化。 结果：40只小鼠和12只兔全部进入结果分析。①^99Tc^m-RGD-4CK标记率为（97．8&;#177;0．4）％，比活度为（11．90&;#177;0．05）PBq／mol；HPLC保留时间与洗脱液放射峰值时间基本一致，室温放置6h的放射化学纯度仍〉95％；SepPakC18柱层析游离^99Tc^m仅比纸层析高0．5％；与300mmol／L半胱氨酸37℃温育1h，游离^99Tc^m仅增加1．88％；^99Tc^m-RGD-4CK与血清蛋白无明显结合。^99Tc^m-RGD-4CK在健康家兔体内的药代动力学符合权重数为1／C的二室模型，分布相半衰期为（4．18&;#177;2．17）min，消除相半衰期为（69．32&;#177;0．00）min。③小鼠血液放射性清除迅速，通过肾脏排泄且快，其余组织器官放射性均随时间逐渐降低，而脑始终呈最低放射水平。④家兔SPECT显像示：各组织器官T—A曲线均随时间逐渐下降，与肾、心、肝相比，肺、胃、肌肉曲线呈低水平；1min双肾即显影，5min心、肝影开始减弱，肺放射性分布均匀，强度低于肝脏，膀胱显影；5min后膀胱影持续增强，20min后软组织影逐渐减弱；胆囊未显影，腹部呈持续低放射分布，胃区始终呈放射性缺损，颈部未见明显核素浓聚。 结论：^99Tc^m-RGD-4CK制备方法简便，标记率高（〉95％），具有良好的放射化学性质，体内稳定性好，具有比较理想的体内动力学。     

~(99)Tc~m标记的ND1重组单链抗体在荷人结肠癌裸鼠体内分布及放射免疫显像研究

目的:探讨99Tcm标记的ND1重组单链抗体(scFv)在荷人结肠癌裸鼠模型体内的生物学分布及放射免疫显像。方法:①荷人结肠癌裸鼠移植瘤模型的建立。②抗体的标记及标记率的测定。③将99Tcm-ND1重组scFv经腹腔和尾静脉注入荷瘤裸鼠体内,分别于注射后1h、3h、8h进行放射免疫显像。取各脏器及肿瘤组织,计算TKNT比值。结果:①99Tcm-ND1重组scFv标记率为85%。②注射后1h肿瘤K血比值为2.62±0.23,3h肿瘤K血比值为3.90±0.25,8h肿瘤K血比值为0.58±0.17。腹腔和尾静脉注射组大肠TKNT值差异有显著性(P<0.05和P<0.005)。99Tcm-ND1重组scFv在荷瘤裸鼠体内生物学分布检测结果示腹腔注入后3h各脏器TKNT比值较高。③放射免疫显像。显像阳性率达100%。以3h显像最清晰。结论9:9Tcm-ND1重组scFv对结肠癌具有良好的亲和力,可望作为结肠癌诊断、预后判定的导向载体。并为临床早期特异性诊断结肠肿瘤提供新的有效手段。     

Loop-acting diuretics do not bind to Tamm-Horsfall urinary glycoprotein

1. Binding between the radiolabelled loop-acting diuretics ([14C]frusemide, [14C]ethacrynic acid and [3H]bumetanide) and human Tamm-Horsfall glycoprotein or human serum albumin in vitro was evaluated by equilibrium dialysis. 2. The diuretic action and binding to urinary Tamm-Horsfall glycoprotein of the radiolabelled diuretics in vivo, after intravenous administration, were examined in rabbits. 3. In vitro, all three radiolabelled diuretics bound strongly to human serum albumin, but not to Tamm-Horsfall glycoprotein. 4. Radiolabelled frusemide and bumetanide, but not ethacrynic acid, caused a diuresis in rabbits, but no binding between the drugs and Tamm-Horsfall glycoprotein was seen in vivo. 5. Binding to Tamm-Horsfall glycoprotein does not appear to be an important mechanism in the action of loop diuretics.     

Pharmacokinetics of SCH 56592, a new azole broad-spectrum antifungal agent, in mice, rats, rabbits, dogs, and cynomolgus monkeys

SCH 56592 is a new broad-spectrum azole antifungal agent that is in phase 3 clinical trials for the treatment of serious systemic fungal infections. The pharmacokinetics of this drug candidate were evaluated following its intravenous (i.v.) or oral (p.o.) administration as a solution in hydroxypropyl-beta-cyclodextrin (HPbetaCD) or oral administration as a suspension in 0.4% methylcellulose (MC) in studies involving mice, rats, rabbits, dogs, and cynomolgus monkeys. SCH 56592 was orally bioavailable in all species. The oral bioavailability was higher with the HPbetaCD solution (range, 52 to approximately 100%) than from the MC suspension (range, 14 to 48%) and was higher in mice ( approximately 100% [HPbetaCD] and 47% [MC]), rats ( approximately 66% [HPbetaCD] and 48% [MC]), and dogs (72% [HPbetaCD] and 37% [MC]) than in monkeys (52% [HPbetaCD] and 14% [MC]). In rabbits, high concentrations in serum suggested good oral bioavailability with the MC suspension. The i.v. terminal-phase half-lives were 7 h in mice and rats, 15 h in dogs, and 23 h in monkeys. In rabbits, the oral half-life was 9 h. In species given increasing oral doses (mice, rats, and dogs), serum drug concentrations were dose related. Food produced a fourfold increase in serum drug concentrations in dogs. Multiple daily doses of 40 mg of SCH 56592/kg of body weight for eight consecutive days to fed dogs resulted in higher concentrations in serum, indicating accumulation upon multiple dosing, with an accumulation index of approximately 2.6. Concentrations above the MICs and minimum fungicidal concentrations for most organisms were observed at 24 h following a single oral dose in MC suspension in all five species studied (20 mg/kg for mice, rats, and rabbits and 10 mg/kg for dogs and monkeys), suggesting that once-daily administration of SCH 56592 in human subjects would be a therapeutically effective dosage regimen.     

不同剂型神经生长因子体内静脉注射的靶向性分布

背景神经生长因子治疗周围神经的损伤已经得到充分的研究并被认可,但其能否通过血脑屏障发挥作用一直不能得到肯定结论,试图以脂质体包裹神经生长因子,并考察其与单纯神经生长因子的对比,证明其能通过血脑屏障,进入中枢神经系统.目的通过单光子发射计算机断层显像技术(single photon emission computerized tomography,SPECT)对比分析不同剂型的神经生长因子经静脉注射后在体内的靶向分布情况.设计以试验动物为研究对象的随机对照研究.单位一所医科大学附属医院.材料实验于2003-06/2004-05于南京森科医药公司,南京医科大学第一附属医院核医学科完成,选用健康新西兰兔3个月龄(19只),普通级,体质量(2.0±0.2)kg,南京安立默科技有限公司提供,随机分组.[99Tcm]-神经生长因子(南京森科医药公司帮助标记,标记率98.9%,放化纯度为99.7%);脂质体(沈阳药科大学提供);200 g/L乌拉坦注射液(南京医科大学试剂科提供).方法将[99Tcm]-神经生长因子用脂质体包裹后,按照以下条件处理将包裹含有1.48×10a Bq[99Tcm]-神经生长因子的脂质体A注射至新西兰兔体内,利用SPECT分析其在脑部分布的百分数.其他两组以相同放射剂量的[99Tcm]-神经生长因子,[99Tcm]-神经生长因子-普通脂质体B处理.主要观察指标静脉注射上述分组药物后,观察其在脑组织中的浓度及放射性计数占全身的百分比.结果自制注射用脂质体A组包裹的[99Tcm]-神经生长因子经SPECT显像,其在脑部的放射性计数较高,而[99Tcm]-神经生长因子组几乎全部从泌尿系统代谢、[99Tcm]-神经生长因子-普通脂质体B组基本被网状内皮系统吞噬后沉积于肝脏.结论此自制神经生长因子-脂质体A具有一定的脑组织靶向性,为携带药物透过血脑屏障奠定基础.     

钙通道阻滞剂对缺血再灌注兔脑皮质一氧化氮、含水量和细胞内游离钙的影响

背景近年来研究发现一氧化氮参与了脑缺血损伤的发生,但对于其确切作用至今尚无统一的结论.目的探讨一氧化氮在缺血再灌注脑损伤中的作用,比较两类钙通道阻滞剂的脑保护作用.设计完全随机设计,对照实验研究.地点和材料实验在首都医科大学附属北京儿童医院ICU实验室完成,实验动物为由首都医科大学动物实验室提供体质量2.0～2.4kg新西兰兔66只. ,方法夹闭双侧颈总动脉和颈动脉30 min后放开制作兔脑缺血再灌注模型.选取36只新西兰兔分为假手术、再灌注0.5、1.5、3、6、24 h共6组,测定脑皮层匀浆一氧化氮及含水量.另选30只新西兰兔分假手术、安慰剂(0.9%生理盐水)、尼莫地平(首剂5μg/kg,20 min内静脉注入,维持量0.5 μg/kg·min)、氯胺酮(首剂20 mg/kg,30 min内静脉注入,维持量10 mg/(kg·h)、尼莫地平+氯胺酮治疗共5组,于再灌注30min开始持续静脉用药至再灌注6h取脑皮层,使用Griess法测定一氧化氮,以Fluo-3 Ca2+荧光试剂标记新鲜活脑片细胞内游离钙([Ca2+]i),激光共聚焦显微镜测定[Ca2+]i相对荧光强度.主要观测指标生理参数变化,再灌注不同时间兔脑皮层一氧化氮及含水量变化,用药组兔脑皮层一氧化氮、含水量、[Ca2+]i.结果再灌注后脑皮层一氧化氮、含水量逐渐升高,于再灌注6h达较高水平[分别为(14.72±1.66)μmol/g,(86.68±1.90)%,P＜0.05],一氧化氮与含水量间具有相关性(r=0.577,P＜0.01).尼莫地平、尼莫地平+氯胺酮组一氧化氮明显降低[分别为(5.08±0.88)、(5.14±1.12)μmol/g,P＜0.01],尼莫地平、氯胺酮以及尼莫地平+氯胺酮组含水量明显降低[分别为(76.31±4.00)、(81.04±1.86)、(78.16±1.41)%,P＜0.01],尼莫地平组较氯胺酮组降低更明显(P＜0.01).安慰剂组[Ca2+]i较假手术组明显升高[分别为(26.84±1.39)、(4.99±0.39),P＜0.01],尼莫地平、氯胺酮及尼莫地平+氯胺酮治疗后[Ca2+]i明显降低[分别为(7.74±1.11)、(13.30±1.99)、(8.97±2.01),P＜0.01].尼莫地平组较氯胺酮组降低更明显(P＜0.01)结论一氧化氮与脑缺血再灌注损伤的发生有密切关系.尼莫地平、氯胺酮均有一定脑保护作用,但氯胺酮作用弱于尼莫地平.     

饮食结构与链脲佐菌素对大白兔血脂组分和动脉粥样硬化形成的作用

背景apoE基因敲除或apoE2转基因小鼠是研究高三酰甘油血症与动脉粥样硬化(atherosclerosis AS)较好模型,但缺乏方便实用的动物模型.目的探讨链脲佐菌素(streptozotocin,STZ)和饮食结构对新西兰大白兔血脂组分及AS的作用,以寻找方便实用的研究高三酰甘油血症与AS动物模型.设计随机对照的实验研究.地点、材料和干预实验在解放军第三军医大学西南医院中心实验室完成.实验选用健康雄性新西兰大白兔.采用随机抽签法分为4组标准兔小颗粒饲养(SC)组;高胆固醇饲料饲养(HC)组;STZ处理后饲养标准兔小颗粒(STZ+SC)组;STZ处理后饲养高胆固醇饲料(STZ+HC)组.比较STZ和高胆固醇饲料对新西大白兔血脂组分和AS病变的作用,并分析AS病变局部清道夫受体A(scavenger receptor,SRA)表达与泡沫细胞分布的关系.主要观察指标观察各组大白兔血浆脂蛋白和载脂蛋白水平和主动脉内膜病理变化,并分析血管内膜粥样硬化斑块局部SRA表达与泡沫细胞分布的关系.结果STZ组大白兔血浆三酰甘油[(2.59±0.64)mmol/L]较SC组[(1.12±0.34)mmol/L]轻-中度升高(P＜0.05)、HDL-C降低及大动脉AS病变;STZ+HC组大白兔的血浆总胆固醇水平[(14.18±2.72)mmol/L]与HC组[(13.74±1.43)mmol/L]相似,而前者的血浆三酰甘油水平[(3.84±0.73)mmol/L]显著高于后者[(1.50±0.35)mmol/L,P＜0.05];STZ+HC组大白兔的AS病变最严重,单纯STZ能导致AS形成,但其AS的严重程度略轻于HC组.STZ所致的血脂紊乱与大多数冠心病患者相似,其AS病变局部的泡沫细胞绝大多数来源于单核巨噬细胞,SRA基因及蛋白质表达与巨噬细胞分布相同,其表达量与AS病变程度一致.结论STZ处理并饲养普通饲料复制出的高三酰甘油血症和AS动物模型是较好的模型.     

Imaging VEGF Receptors and α<Subscript>v</Subscript>β<Subscript>3</Subscript> Integrins in a Mouse Hindlimb Ischemia Model of Peripheral Arterial Disease

Purpose

To compare targeted imaging of vascular endothelial growth factor (VEGF) receptors vs. α_vβ₃ integrins in a mouse hindlimb ischemia model of peripheral artery disease.

Procedures

Male wild-type (WT) C57BL/6 mice (8- to 10-week old) (n?=?24) underwent left femoral artery ligation. The right leg served as control. Five days later, mice were injected with either VEGF receptor targeting [^99mTc]DOTA-PEG-scVEGF ([^99mTc]scV) (n?=?8) or with α_vβ₃-targeting tracer [^99mTc]HYNIC-cycloRGD ([^99mTc]RGD) (n?=?8) and underwent single photon emission computed tomography (SPECT) x-ray computed tomography imaging. To assess non-specific [^99mTc]scV uptake, six additional mice received a mixture of [^99mTc]scV and 30-fold excess of targeting protein, scVEGF. Tracer uptake as %ID was measured using volumetric regions encompassing the hindlimb muscles and as %ID/g from harvested limb muscles. Double and triple immunofluorescent analysis on tissue sections established localization of α_vβ₃, VEGFR-1, VEGFR-2, as well as certain cell lineage markers.

Results

Tracer uptake, as %ID/g, was higher in ligated limbs of mice injected with [^99mTc]scV compared to ligated hindlimbs in mice injected with [^99mTc]RGD (p?=?0.02). The ratio of tracer uptake for ligated/control hindlimb was borderline higher for [^99mTc]scV than for [^99mTc]RGD (p?=?0.06). Immunofluorescent analysis showed higher prevalence of VEGFR-1, VEGFR-2, and α_vβ₃, in damaged vs. undamaged hindlimb tissue, but with little co-localization of these markers. Double immunofluorescent staining showed partial co-localization of VEGFR-1, VEGFR-2, and α_vβ_3, with endothelial cell marker FVIII, but not with CD31. Immunostaining for VEGFR-1 and VEGFR-2 additionally co-localized with lineage markers for endothelial progenitor cell and monocytes/macrophages, with a more diverse pattern of co-localization for VEGFR-2.

Conclusion

In a mouse hindlimb ischemia model of peripheral artery disease, [^99mTc]scV SPECT tracer-targeting VEGF receptors showed a more robust signal than [^99mTc]RGD tracer-targeting α_vβ₃. Immunofluorescent analysis suggests that uptake of [^99mTc]scV and [^99mTc]RGD in damaged tissue is due to non-overlapping cell populations and reflects different dynamic processes and that enhanced uptake of [^99mTc]scV may be due to the presence of VEGF receptors on additional cell types.

     

In vivo activities and penetration of the two components of the streptogramin RP 59500 in cardiac vegetations of experimental endocarditis.

We evaluated the in vivo activity and the diffusion of radiolabelled RP 57669 (RPI) and RP 54476 (RPII), the two components of the injectable streptogramin RP 59500, alone or in combination, in aortic vegetations from experimental endocarditis in rabbits. RPI and RPII demonstrated in vitro bacteriostatic and bactericidal synergy against a clinical strain of Staphylococcus aureus resistant to methicillin and susceptible to erythromycin. In experimental staphylococcal endocarditis, RP 59500 was as effective as vancomycin and significantly more effective than RPI (P < 0.01) and RPII (P < 0.05). Autoradiography studies showed different patterns of distribution into cardiac vegetations infected with Streptococcus sanguis for [14C]RPI and [14C]RPII. [14C]RPI was homogeneously distributed throughout the vegetations whereas [14C]RPII showed a decreasing gradient of concentration between the periphery and the core of the vegetation, with an approximately 2:1 ratio. [14C]RPI diffused approximately 2 to 4 times more than [14C]RPII into the core of the vegetations. Since the injected ratio of RPI and RPII is 30:70 in RP 59500, the actual RPI:RPII ratio in the core of the vegetation may range from 0.8 to 1.7, a ratio which remains compatible with the in vivo synergism demonstrated between the two components.     

pH-Sensitive,Long-Circulating Liposomes as an Alternative Tool to Deliver Doxorubicin into Tumors: a Feasibility Animal Study

Purpose

Therapeutic agents used in chemotherapy have low specificity leading to undesired severe side effects. Hence, the development of drug delivery systems that improve drug specificity, such as liposome moieties, is an alternative to overcome chemotherapy limitations and increase antitumor efficacy. In this study, the biodistribution profile evaluation of pH-sensitive long-circulating liposomes (SpHL) containing [^99mTc]DOX in 4T1 tumor-bearing BALB/c mice is described.

Procedures

[^99mTc]DOX was radiolabeled by direct method. Liposomes were prepared and characterized. [^99mTc]DOX was encapsulated into liposomes by freezing and thawing. Circulation time for SpHL-[^99mTc]DOX was determined by measuring the blood activity from healthy animals. Biodistribution studies were carried out in tumor-bearing mice at 1, 4, and 24 h after injection.

Results

Blood levels of the SpHL-[^99mTc]DOX declined in a biphasic manner, with an α half-life of 14.1 min and β half-life of 129.0 min. High uptake was achieved in the liver and spleen, due to the macrophages captured. Moreover, tumor uptake was higher than control tissue, resulting in high tumor-to-muscle ratios, indicating higher specificity for the tumor area.

Conclusion

[^99mTc]DOX was successfully encapsulated in liposomes. Biodistribution indicated high tumor-to-muscle ratios in breast tumor-bearing BALB/c mice. In summary, these results showed the higher accumulation of SpHL-[^99mTc]DOX in the tumor area, suggesting selective delivery of doxorubicin into tumor.

     

Multimodal <Emphasis Type="Italic">In Vivo</Emphasis> Imaging of Tumorigenesis and Response to Chemotherapy in a Transgenic Mouse Model of Mammary Cancer

Purpose

Transgenic mice expressing the polyoma middle T oncoprotein (PyMT) in the mammary epithelium were explored by multimodal imaging to monitor longitudinally spontaneous tumor growth and response to chemotherapy.

Procedures

Positron emission tomography (PET) with 2-deoxy-2-[¹⁸F]fluoro-d-glucose ([¹⁸F]FDG) and 3'-deoxy-3'-[¹⁸F]fluorothymidine ([¹⁸F]FLT), single photon emission tomography (SPECT) with [^99mTc]TcO₄ ([^99mTc]TEC), X-ray computed tomography, and fluorescent confocal endomicroscopy (FCE) images were acquired during tumor progression in female PyMT mice. Imaging with [¹⁸F]FDG and [^99mTc]TEC was also performed in untreated, doxorubicin-treated, and docetaxel-treated PyMT mice. Total tumor volumes were quantified. Tumors were collected and macroscopic and histological examinations were performed.

Results

All PyMT mice developed multifocal tumors of the mammary epithelium that became palpable at 8 weeks of age (W8). Computed tomography (CT) detected tumors at W14, while a clear tumoral uptake of [^99mTc]TEC and [¹⁸F]FDG was present as early as W6 and W8, respectively. No contrast between mammary tumors and surrounding tissue was observed at any stage with [¹⁸F]FLT. FCE detected an angiogenic switch at W10. Lung metastases were not clearly evidenced by imaging. Doxorubicin and docetaxel treatments delayed tumor growth, as shown by [¹⁸F]FDG and [^99mTc]TEC, but tumor growth resumed upon treatment discontinuation. Tumor growth fitted an exponential model with time constant rates of 0.315, 0.145, and 0.212 week^?1 in untreated, doxorubicin, and docetaxel groups, respectively.

Conclusions

Molecular imaging of mammary tumors in PyMT is precocious, precise, and predictive. [¹⁸F]FDG-PET and [^99mTc]TEC SPECT monitor tumor response to chemotherapy.

     

Mack Forster Award Lecture Receptor nuclear medicine: vasointestinal peptide and somatostatin receptor scintigraphy for diagnosis and treatment of tumour patients

The multiple aspects of radioligand–receptor interactions do not only show a major impact of certain cell surface-bound receptors in the pathophysiology of human disease: the concept of radioligand–receptor interactions has also been extended to the clinic. In particular, naturally occurring peptides, when radiolabelled, are clinically useful for the imaging diagnosis of human disease and have future implications for the treatment of tumour expressing certain target receptors using radiolabelled peptide tracers. The finding that receptors for VIP (vasoactive intestinal peptide) and SST (somatostatin) are overexpressed on tumour cells presents a breakthrough into this direction. Recent data indicate that [¹²³I]-VIP receptor scintigraphy is clinically useful for the in vivo localization of small primary adenocarcinomas, liver metastases and certain endocrine tumours of the gastrointestinal tract. After the successful clinical introduction of the SST analogues [¹²³I]-Tyr³-octreotide and [¹¹¹In]-DTPA- d -Phe¹-octreotide for localization diagnosis of neuroendocrine tumours in 1989, P829, labelled with the more cost-effective radionuclide ^99mTc, nowadays promises to be a potential novel diagnostic imaging agent for tumours expressing SST/VIP receptors. Furthermore, the novel SST analogue [⁹⁰Y]-MAURITIUS is entering the clinic for treatment of VIP/SST receptor-expressing tumours.