Imaging gene expression in the brain in vivo in a transgenic mouse model of Huntington's disease with an antisense radiopharmaceutical and drug-targeting technology.

Disease-specific genes of unknown function can be imaged in vivo with antisense radiopharmaceuticals, providing the transcellular transport of these molecules is enabled with drug-targeting technology. The current studies describe the production of 16-mer peptide nucleic acid (PNA) that is antisense around the methionine initiation codon of the huntingtin gene of Huntington's disease (HD). METHODS: The PNA is biotinylated, which allows for rapid capture by a conjugate of streptavidin and the rat 8D3 monoclonal antibody (mAb) to the mouse transferrin receptor (TfR), and contains a tyrosine residue, which enables radiolabeling with 125I. The reformulated PNA antisense radiopharmaceutical that is conjugated to the 8D3 mAb is designated 125I-PNA/8D3. This form of the PNA is able to access endogenous transferrin transport pathways at both the blood-brain barrier and the brain cell membrane and undergoes both import from the blood to the brain and export from the brain to the blood through the TfR. RESULTS: The ability of the PNA to hybridize to the target huntingtin RNA, despite conjugation to the mAb, was shown both with cell-free translation assays and with ribonuclease protection assays. The 125I-PNA/8D3 conjugate was administered intravenously to either littermate control mice or to R6/2 transgenic mice, which express the exon 1 of the human HD gene. The mice were sacrificed 6 h later for frozen sectioning of the brain and quantitative autoradiography. The studies showed a 3-fold increase in sequestration of the 125I-PNA/8D3 antisense radiopharmaceutical in the brains of the HD transgenic mice in vivo, consistent with the selective expression of the HD exon-1 messenger RNA in these animals. CONCLUSION: These results support the hypothesis that gene expression in vivo can be quantitated with antisense radiopharmaceuticals, providing these molecules are reformulated with drug-targeting technology. Drug targeting enables access of the antisense agent to endogenous transport pathways, which permits passage across the cellular barriers that separate blood and intracellular compartments of target tissues.     

99Tcm—survivinmRNA反义肽核酸制备及荷瘤裸鼠基因显像研究

目的制备99Tcm标记的survivinmRNA反义肽核酸（PNA）探针,并进行荷瘤裸鼠体内基因显像,研究其对肿瘤早期诊断的价值。方法化学合成survivinmRNA的反义、无义PNA,在5’端连上4个氨基酸[Gly一（D）Ala—Gly—Gly],形成1个类似N。结构的强螯合基团;为消除空间阻碍,引入1个1一氨基丁酸（Aba）作为隔离物,利用配体交换法进行99Tcm标记。用HPLC及ITLC对标记物的标记率、放化纯进行鉴定。并对反义、无义组各5只人肺癌A549荷瘤裸鼠行99Tcm一survivinmRNA反义、无义PNA体内显像。注药后1,2和4h分别显像,利用ROI测得肿瘤与对侧组织的rr／NT比值。结果分析采用SPSS13．0软件进行成组t检验。结果99Tcm一survivinmRNA反义PNA即刻标记率为（95．48±1．92）％,放化纯〉95％,且标记物体外稳定性好,与血清保温24h后标记率仍〉85％。无义PNA标记率与之基本一致。99Tcm一survivinmRNA反义PNA在肿瘤组织内特异性浓聚,随时间延长,浓聚程度逐渐增加,1,2和4hT／NT值分别为2．70±0．28,3．44±0．35和4．21±0．63。无义PNA在肿瘤组织中稍有浓聚,但在4h内变化不大,4h时T／NT值（3．12±0．50）与反义组差异有统计学意义（t=2．918,P：0．019）。结论99TcmsurvivinmRNA反义PNA即刻标记率高,稳定性好,无需纯化即可用于显像,在肿瘤组织中特异性浓聚,对肿瘤的早期诊断有潜在价值。     

反义胶原纤维酸性蛋白逆转录病毒对胶质瘢痕增生的影响

研究抑制胶原纤维酸性蛋白基因表达对在体胶质瘢痕形成的影响。方法构建反义ＧＦＡＰ逆转录病毒表达载体,经过病毒包装后,将获得的病毒上清液浓缩并通过微量注射的方法,引入大鼠脑穿刺损伤灶内,采用免疫组化及形态学观察的方法,研究重组反义ＧＦＡＰ逆转录病毒对脑损伤后胶质瘢痕形成的影响。     

Sequence-specific DNA strand cleavage by <Superscript>111</Superscript>In-labeled peptide nucleic acids

Peptide nucleic acids (PNAs) bind tightly and sequence-specifically to single- and double-stranded nucleic acids, and are hence of interest in the design of gene-targeted radiotherapeutics that could deliver the radiodamage to designated DNA and/or RNA sites. As a first step towards this goal, we developed a procedure for incorporation of Auger electron-emitting radionuclide (indium-111) into PNA oligomers and studied the efficiency of PNA-directed cleavage of single-stranded DNA targets. Accordingly, diethylene triamine penta-acetic acid (DTPA) was conjugated to the lysine-appended mixed-base PNAs and sequence-homologous DNA oligomer with a proper linker for comparative studies. By chelation of PNA-DTPA and DNA-DTPA conjugates with ¹¹¹In³⁺ in acidic aqueous solutions, ¹¹¹In-labeled PNA and DNA oligomers were obtained. Targeting of single-stranded DNA with PNA-DTPA-[¹¹¹In] conjugates yielded highly localized DNA strand cleavage; the distribution of breaks along the target DNA strand has two maxima corresponding to both termini of PNA oligomer. After 10–14 days, the overall yield of breaks thus generated within the PNA-targeted DNA by ¹¹¹In decay was 5–7% versus 2% in the case of control oligonucleotide DNA-DTPA-[¹¹¹In]. The estimated yield of DNA strand breaks per nuclear decay is ~0.1 for the PNA-directed delivery of ¹¹¹In, which is three times more than for the DNA-directed delivery of this radionuclide. This in vitro study shows that ¹¹¹In-labeled PNAs are much more effective than radiolabeled DNA oligonucleotides for site-specific damaging of DNA targets. Accordingly, we believe that PNA oligomers are promising radionuclide delivery tools for future antisense/antigene radiotherapy trials.     

99Tcm-c-myc mRNA反义肽核酸荷结肠癌裸鼠显像

目的 制备99Tcm-c-myc mRNA反义肽核酸(PNA)显像探针,通过反义显像研究99Tcm-c-myc mRNA反义PNA早期诊断结肠癌的可行性.方法 利用化学合成法在c-myc mRNA反义PNA片段的5'端连上4个氨基酸[G-(D)-A-G-G]和1个氨基丁酸(Aba),再利用配体交换法对c-myc mRNA反义PNA行99Tcm标记.并用同样的方法制备99Tcm-c-myc mRNA无义PNA.进行人结肠癌LS174-T荷瘤裸小鼠显像.采用SAS 6.12软件进行统计学处理.结果 99Tcm-c-myc mRNA反义PNA 6h内标记率＞95%.血清孵育5h后标记率为91.1%.无义PNA的标记率与反义PNA基本一致.1h时反义组荷瘤裸鼠右后肢肿瘤部位可清晰显影,4h内未见明显变化.无义组肿瘤部位始终未见明显放射性摄取.注射99Tcm-c-myc mRN反义PNA 1h后,反义组与无义组肿瘤与对侧组织的放射性(T/N)比值分别为5.06±1.35和1.53±0.30,差异有统计学意义(t=4.47, P=0.04).结论 99Tcm-c-myc mRNA反义PNA可在荷瘤裸鼠活体内与高表达c-myc基因的人结肠癌LS174-T肿瘤组织特异结合,在肿瘤反义显像中有潜在的应用价值.     

+Gz重复暴露对大鼠脑胶质细胞酸性蛋白表达的影响

目的 探讨＋Gz重复暴露对星形胶质细胞中胶质原纤维酸性蛋白（GFAP）表达的影响。方法 SD大鼠40只，随机分为4组，即对照组（5只）、＋4Gz锻炼组（15只）、＋4Gz锻炼后再暴露于 10Gz组（15只）及单次＋10Gz暴露组（5只）。各组暴露后2d处死取脑，做冰冻切片，免疫组织化学染色观察GFAP的表达情况。结果 4Gz/3min暴露1次、3次和5次后（两次之间间隔24h)，GFAP阳性细胞数由少至多，以细小型为主；单次＋10Gz暴露后，GFAP阳性反应较强，肥大型在梨状皮层和丘脑下部最多，在顶叶皮层和海马较少；＋4Gz分别暴露1次、3次和5次后再暴露于＋10Gz，肥大型在各脑区逐渐减少，在顶叶皮层和海马逐渐消失，代之以细小型。结论 低G值反复暴露后再暴露于高G值对脑的保护作用，与其能减少肥大、肿胀和损伤的GFAP阳性细胞有一定的相关性。     

高+Gz重复暴露对大鼠脑组织胶质纤维酸性蛋白表达的影响

目的观察高＋Gz重复暴露后脑组织星形胶质细胞中胶质纤维酸性蛋白（GFAP）表达的变化。方法SD大鼠30只，随机分为对照组和＋10G；暴露组。＋G2暴露组的大鼠暴露于＋10Gz／45S，共暴露5次，中间间隔5min。分别于＋Gz暴露后不同时间灌注取脑，免疫组织化学染色观察脑GFAP的表达情况。结果＋Gz暴露后1d、2d，顶叶皮层、海马GFAP阳性细胞数较对照组均显著增多（P〈0．05），以弱阳性细小型为主；暴露后4d、6d，顶叶皮层、海马GFAP阳性细胞数较对照组进一步增多（P〈0．01），以中等阳性细胞为主，肥大的GFAP增多。结论重复暴露＋10Gz／45s可引起大鼠顶叶皮层、海马GFAP表达显著增加。     

细胞周期调控对缺血缺氧性脑损伤后星形胶质细胞增殖的影响

目的探讨局灶性脑梗死后细胞周期调控对星形胶质细胞增殖的影响。方法光化学方法制作大鼠缺血模型，腹腔注射细胞周期抑制剂Olomoucine进行干预。应用免疫组织化学法观察缺血后30d假手术组、对照缺血组和干预组（按8mg／kg给予Olomoucine）损伤侧皮层病灶周围胶质纤维酸性蛋白（glial fibriliary acidic proten，GFAP）阳性表达；免疫印迹法（Westem blot）观察GFAP和增殖细胞核抗原（proliferation cell nuclear antigen，PCNA）蛋白的表达；半定量逆转录一聚合酶链反应法（RT-PCR）观察GFAP mRNA的表达；HE染色测定皮层中风囊的体积。结果缺血后30d缺血组损伤侧皮质有明显的中风囊，形成胶质瘢痕，且周围胶质细胞增殖、活化呈密集型改变；对照组GFAP mRNA的表达最明显（P〈0．05）；干预组损伤侧皮质中风囊体积明显减小（P〈0．05），胶质细胞增殖明显受到抑制（P〈0．05），且GFAP和PCNA蛋白表达明显减弱（P〈0．05）。结论细胞周期调控可部分抑制胶质细胞的活化、增殖及瘢痕的形成。     

Molecular imaging of bcl-2 expression in small lymphocytic lymphoma using 111In-labeled PNA-peptide conjugates.

The bcl-2 gene is overexpressed in non-Hodgkin's lymphoma (NHL), such as small lymphocytic lymphoma (SLL), and many other cancers. Noninvasive imaging of bcl-2 expression has the potential to identify patients at risk for relapse or treatment failure. The purpose of this study was to synthesize and evaluate radiolabeled peptide nucleic acid (PNA)-peptide conjugates targeting bcl-2 gene expression. An (111)In-labeled PNA complementary to the translational start site of bcl-2 messenger RNA was attached to Tyr(3)-octreotate for somatostatin receptor-mediated intracellular delivery. METHODS: DOTA-anti-bcl-2-PNA-Tyr(3)-octreotate (1) and 3 control conjugates (DOTA-nonsense-PNA-Tyr(3)-octreotate (2), DOTA-anti-bcl-2-PNA-Ala[3,4,5,6]-substituted congener (3), and DOTA-Tyr(3)-octreotate (4) [DOTA is 1,4,7,10-tetraazacyclododecane-N,N',N',N'-tetraacetic acid]) were synthesized by standard solid-phase 9-fluorenylmethoxycarbonyl (Fmoc) chemistry. In vitro studies were performed in Mec-1 SLL cells, which express both bcl-2 messenger RNA and somatostatin receptors. Biodistributions and microSPECT/CT studies were performed in Mec-1-bearing SCID (severe combined immunodeficiency) mice, a new animal model of human SLL. RESULTS: (111)In-Labeled conjugate 1 was taken up by Mec-1 cells through a somatostatin receptor-mediated mechanism. Biodistribution studies showed specific tumor uptake of conjugate 1, the somatostatin analog 4, and the PNA nonsense conjugate 2, but not of the mutant peptide conjugate 3. Mec-1 tumors could be detected by microSPECT/CT using (111)In-labeled DOTA-Tyr(3)-octreotate (4) and the targeted anti-bcl-2 conjugate (1), but not using the 2 negative control conjugates 2 and 3. CONCLUSION: A new (111)In-labeled antisense PNA-peptide conjugate demonstrated proof of principle for molecular imaging of bcl-2 expression in a new mouse model of human SLL. This imaging agent may be useful for identifying NHL patients at risk for relapse and conventional treatment failure.     

推拉动作对大鼠脑GFAP表达的影响

目的 观察推拉动作后大鼠脑星形胶质细胞中胶质纤维酸性蛋白(GFAP)表达的改变.方法 雄性SD大鼠44只,随机分为对照组、 10 Gz暴露组、推拉动作组,分别于暴露后不同时间灌注取脑,免疫组织化学染色观察脑GFAP的表达情况.结果 10 Gz暴露后6 h,顶叶皮层、海马、丘脑可见GFAP呈中等强度的阳性反应,阳性细胞数较对照组显著增多(P＜0.01),多为中等阳性细小型;暴露后1 d、2 d、4 d和6 d,GFAP阳性反应程度进一步增强,阳性细胞数进一步增多.推拉动作组暴露后各时间点,顶叶皮层、海马、丘脑GFAP呈较强的阳性反应,阳性细胞数较 10 Gz暴露组显著增多(P＜0.01),以强阳性肥大型为主.结论 10 Gz/3 min 暴露可引起大鼠顶叶皮层、海马、丘脑GFAP表达显著增加,而推拉动作组比 10 Gz暴露组引起脑组织GFAP的表达增加更明显.     

A comparison of EGF and MAb 528 labeled with 111In for imaging human breast cancer.

Our objective was to compare 111In-labeled human epidermal growth factor (hEGF), a 53-amino acid peptide with anti-epidermal growth factor receptor (EGFR) monoclonal antibody (MAb) 528 (IgG2a) for imaging EGFR-positive breast cancer. METHODS: hEGF and MAb 528 were derivatized with diethylenetriamine pentaacetic acid (DTPA) and labeled with 111In acetate. Receptor binding assays were conducted in vitro against MDA-MB-468 human breast cancer cells. Biodistribution and tumor imaging studies were conducted after intravenous injection of the radiopharmaceuticals in athymic mice bearing subcutaneous MCF-7, MDA-MB-231, or MDA-MB-468 human breast cancer xenografts or in severe combined immunodeficiency mice implanted with a breast cancer metastasis (JW-97 cells). MCF-7, MDA-MB-231, JW-97, and MDA-MB-468 cells expressed 1.5 x 10(4), 1.3 x 10(5), 2.7 x 10(5), and 1.3 x 106 EGFR/cell, respectively in vitro. RESULTS: 111In-DTPA-hEGF and 111In-DTPA-MAb 528 bound with high affinity to MDA-MB-468 cells (Ka of 7.5 x 10(8) and 1.2 x 10(8) L/mol, respectively). 111In-DTPA-hEGF was eliminated rapidly from the blood with < 0.2% injected dose/g (%ID/g) circulating at 72 h after injection, whereas 111In-DTPA-MAb 528 was cleared more slowly (3%ID/g in the blood at 72 h). Maximum localization of 111In-DTPA-hEGF in MDA-MB-468 tumors (2.2 %ID/g) was 10-fold lower than with 111In-DTPA-MAb 528 (21.6 %ID/g). There was high uptake in the liver and kidneys for both radiopharmaceuticals. Tumor-to-blood ratios were greater for 111In-labeled hEGF than for MAb 528 (12:1 versus 6:1), but all other tumor-to-normal tissue ratios were higher for MAb 528. MDA-MB-468 and JW-97 tumors were imaged successfully with both radiopharmaceuticals, but tumors were more easily visualized using 111In-labeled MAb 528. There was no direct quantitative relationship between EGFR expression on breast cancer cell lines in vitro, and tumor uptake of the radiopharmaceuticals in vivo, but control studies showed that tumor uptake was receptor mediated. CONCLUSION: Our results suggest that the tumor uptake in vivo of receptor-binding radiopharmaceuticals is controlled to a greater extent by their elimination rate from the blood than by the level of receptor expression on the cancer cells. Radiolabeled anti-EGFR MAbs would be more effective for tumor imaging in cancer patients than peptide-based radiopharmaceuticals such as hEGF, because they exhibit higher tumor uptake at only moderately lower tumor-to-blood ratios.     

Molecular pathology of brain matrix metalloproteases,claudin5, and aquaporins in forensic autopsy cases with special regard to methamphetamine intoxication

Methamphetamine (METH) is a highly addictive drug of abuse and toxic to the brain. Recent studies indicated that besides direct damage to dopamine and 5-HT terminals, neurotoxicity of METH may also result from its ability to modify the structure of blood-brain barrier (BBB). The present study investigated the postmortem brain mRNA and immunohistochemical expressions of matrix metalloproteases (MMPs), claudin5 (CLDN5), and aquaporins (AQPs) in forensic autopsy cases of carbon monoxide (n?=?14), METH (n?=?21), and phenobarbital (n?=?17) intoxication, compared with mechanical asphyxia (n?=?15), brain injury (n?=?11), non-brain injury (n?=?21), and sharp instrument injury (n?=?15) cases. Relative mRNA quantification using Taqman real-time PCR assay demonstrated higher expression of AQP4 and MMP9, lower expression of CLDN5 in METH intoxication cases and lower expression of MMP2 in phenobarbital intoxication cases. Immunostaining results showed substantial interindividual variations in each group, showing no evident differences in distribution or intensity among all the causes of death. These findings suggest that METH may increase BBB permeability by altering CLDN5 and MMP9, and the self-protective system maybe activated to eliminate accumulating water from the extracellular space of the brain by up-regulating AQP4. Systematic analysis of gene expressions using real-time PCR may be a useful procedure in forensic death investigation.     

Hybridization and cell uptake studies with radiolabelled antisense oligonucleotides

BACKGROUND: Radiolabelled antisense oligonucleotides have been proposed as radiopharmaceuticals for imaging changes in the level of gene expression in vivo. This paper describes a study of the uptake of radiolabelled oligonucleotides in cell lines expressing different levels of the target mRNA. METHODS: A 15-mer phosphorodiester deoxyoligonucleotide antisense to c-myc was labelled with 99mTc and 32P. Hybridization and stability studies were performed in vitro. Cell uptake studies were carried out in a c-myc expressing transformed rat embryonic fibroblast cell-line, TGR-1, and a knock-out cell line HO15.19 which does not express c-myc. RESULTS: The oligonucleotides were efficiently labelled with both radionuclides and retained their ability to hybridize with their complementary mRNA when extracted from cell lines. The radiolabelled oligonucleotides were stable for a few hours in human serum. No statistically significant difference was found between the uptake of radioactivity by the two cell lines. CONCLUSIONS: Although able to bind efficiently to their target in cell-free systems, radiolabelled oligonucleotides may be prevented from performing effectively as radiopharmaceutical vectors by the barriers imposed by cell membranes and/or intracellular metabolism.     

脑源性神经营养因子对亚低温处理后移植干细胞的存活及分化的影响

目的 研究脑源性神经营养因子(brain-derived neurotrophic factor,BDNF)对亚低温处理后移植干细胞的存活及分化的影响.方法 脂质体介导BDNF表达质粒转染293T细胞,ELISA法确定BDNF高峰表达时相,收集高表达时相阶段细胞上清液.建立SD大鼠液压脑创伤模型,分为A组(干细胞移植组)和B组(干细胞移植+BDNF组),两组同时给予亚低温治疗(33℃)5 d.对第4天和第8大(复温后第3天)脑组织标本行增殖细胞核抗原(PCNA)、巢蛋白(nestin)、神经元特异性烯醇化酶(NSE)、胶质纤维酸性蛋白(GFAP)的免疫组织化学及原位细胞凋亡检测,实验动物予以神经功能缺陷评分.结果 ELISA结果显示细胞转染48～60 h后BDNF持续高表达.亚低温处理第4天两组PCNA、巢蛋白均高表达,NSE及GFAP无或极低表达,细胞凋亡少见,但B组较A组更少(P＜0.05).复温后第3天两组PCNA、巢蛋白均表达下降,NSE及GFAP表达升高,但B组较A组NSE阳性率更高,细胞凋亡更少(P＜0.05).B组获得最佳动物神经功能评分.结论 BDNF可增加低温环境下的干细胞存活率,并诱导干细胞向神经元分化.

Abstract：

Objective To study the effect of brain-derived neurotrophic factor (BDNF) on the environmental nutrition and neural differentiation of the transplanted stem cells under hypothermia.Methods The BDNF gene mediated by liposome was transfected into 293T cell line, and ELISA assay was applied to find the peak time of BDNF expression. When BDNF was highly expressed, the supernatant was collected for establishment of SD rat models of brain injury. The rats were divided into Group A (stem cell transplantation group) and Group B (stem cell transplantation and BDNF group). Rats in both groups were under hypothermia treatment for five days. Four and eight days later ( three days from rewarming), rat brain tissues were obtained to detect the expressions of proliferating cell nuclear antigen (PCNA), nestin, neuron-specific enolase (NSE) and glial fibrillary acidic protein (GFAP) by immunohistochemical method and to detect the apoptosis by in situ hybridization. Finally, the nerve function scores were obtained for evaluation of the nerve function. Results The ELISA showed that the high level of BDNF expression was at 48 to 60 hours after gene transfection. PCNA and nestin were highly expressed, while NES and GFAP showed nil or low level of expression in both groups at the fourth day after hypothermia, with little apoptotic cells especially in the Group B (P ＜0.05). The expressions of PCNA and nestin were decreased, but the expressions of NSE and GFAP were increased at the third day after rewarming. The positive rate of NSE expression in the Group B was much higher and the apoptotic cells were much less compared with the Group A ( P ＜ 0. 05 ). A better nerve score was obtained in the Group B. Conclusion BDNF can enhance the survival rate of the transplanted stem cells and induce their differentiation into neurons under hypothermia.     

热休克蛋白70封闭后对星形胶质细胞反应性增生的影响

目的 探讨用抗体封闭热休克蛋白70(heat shock protein 70,HSP70)后对星形胶质细胞反应性增生的影响. 方法 原代培养并纯化星形胶质细胞,采用划痕损伤法构建细胞损伤模型,通过培养液内加入HSP70抗体来进行干预.在不同时间点对损伤对照组和损伤干预组进行胶质纤维酸性蛋白(GFAP)免疫细胞化学染色,观察细胞增生情况及形态学变化,并用RT-PCR检测GFAP mRNA的表达. 结果 与对照组相比,干预组细胞面积、突起数目及突起长度均减小(P<0.05或0.01),GFAP mRNA的表达也明显降低(P<0.05). 结论 星形胶质细胞损伤后,HSP70有促进星形胶质细胞反应性增生的作用.用抗体封闭HSP70后,能够一定程度上抑制星形胶质细胞的反应性增生.     

99Tcm标记反义肽核酸探针的制备及其荷瘤裸鼠体内分布

目的 探讨99Tcm标记反义肽核酸(PNA)探针的新方法及其在生物体内的分布.方法 合成12mer且5'端含有四肽G-(D)-A-G-G的c-myc mRNA反义、无义PNA片段,利用G-(D)-A-G-G形成的N4结构为螯合基团进行99Tcm标记,用聚酰胺薄膜层析法和高效液相色谱仪法(HPLC)测定其标记率和标记物的稳定性,并行人结肠癌荷瘤裸鼠体内分布[每克组织百分注射剂量率(%ID/g)]及显像研究.采用SAS 6.22软件对数据进行分析.结果 反义、无义PNA片段合成物的纯度>95%.99Tcm标记c-myc mRNA反义、无义PNA的标记率>95%,标记物室温放置18 h测定其标记率仍可达95%以上.c-myc mRNA反义、无义PNA片段4～8℃下放置3个月标记率仍>95%.HPLC测定标记物呈单峰.99Tcm标记c-myc mRNA反义PNA主要分布在荷瘤鼠肾、脾、肿瘤、肠道、肝组织中,99Tcm标记c-myc mRNA无义PNA在荷瘤鼠血液、脾、肾、肝及肺组织中分布较多;注射后4 h两者在荷瘤鼠肿瘤组织中的分布差异有统计学意义[(1.11±0.12)%ID/g和(0.14±0.02)%ID/g;t=14.75,P<0.01].99Tcm标记c-mycmRNA反义PNA在小鼠体内肿瘤/肌肉、肿瘤/肺的摄取比值较高,肿瘤显像明显.结论 用99Tcm标记c-myc mRNA反义、无义PNA的方法简单,标记率高,标记物稳定,前者有望成为一种新型肿瘤显像剂.     

^99Tc^m—survivin mRNA反义肽核酸基因显像在肿瘤与炎性反应模型中的对比研究

目的研究^99Tc^m-survivin mRNA反义肽核酸（PNA）显像在肿瘤特异性诊断中的价值。方法用^99Tc^m标记人工合成的12碱基单链survivin mRNA反义PNA。20只荷瘤（A549）裸鼠按随机数字表法分为4组,每组5只。每只裸鼠经尾静脉注入^99Tc^m-survivin mRNA反义PNA,3组进行体内分布研究,其余进行显像研究。用同样方法对20只炎性反应（金黄色葡萄球菌）小鼠进行分组、体内分布和显像研究。采用SPSS13．0软件进行统计学分析,组间计量资料比较采用t检验。结果^99Tc^m-survivin mRNA反义PNA在肝内分布最高,其次是肾,注射后4h肿瘤组靶／非靶（T／NT）比值明显高于炎性反应组,分别为3．69±1．13,2．03±0．47,差异有统计学意义（t=3．01,P=0．02）。肿瘤组在注射药物后0．5h即可见肿瘤清晰显影,至4h时显影仍较清晰,而炎性反应部位始终未见明显显影。结论^99Tc^m-survivin mRNA反义PNA基因显像可通过其在肿瘤组织中的特异性浓聚区分肿瘤与炎性反应,为肿瘤的特异性诊断提供了一种可能的新方法。