Objective To study the effect of two-step pretargeting radioimmunotherapy of CD45 McAb and 188Re-Avidin on lymphoma Raji cell line.Methods The CD45 McAb and Avidin were directly labeled with 188Re,and the labeling efficiency and radiochemical purity were measured by the paper chromatography.The specific binding test and competition binding test between 188 Re-CD45 McAb and Raji cells in vitro were also performed.CCK-8 assay was used to determine the inhibition effect on Raji cell proliferation in the pretargeted group,188Re-CD45 McAb,188Re-Avidin and 188ReO4 groups,then the cell survival and proliferation inhibition rate were calculated.Results The specific cell binding rate of 188Re-CD45 McAb with Raji cells was (70.92 ± 1.91) ％,in the competition group,the binging rate of 188Re-CD45 McAb with Raji cells was only (7.96 ± 0.87)％.The Raji cells proliferation was inhibited in all groups with 188Re radiolabel,and the inhibition rate was positively correlated with the radioactivity dose (r=0.907-0.992,P ＜0.05).However,at the same dose,the inhibition effect in the group of two-step pretargeting at each time point were all stronger than those of 188Re-CD45 McAb,188Re-Avidin and 188 ReO4-alone (t =124.76-607.98,P ＜ 0.05).But there was no significantly statistical difference in the inhibitory effect between the groups of 188Re-Avidin and 188ReO4-(P ＞ 0.05).Conclusions It is confirmed that 188Re-CD45 McAb could be specifically bound to Raji cells,and the two-step pretargeting of CD45 McAb and 188Re-Avidin has obvious inhibitory effect on the Raji cell proliferation.

Objective To establish rat models of extrahepatic biliary atresia,and to observe the characteristics of 99Tcm-MIBI hepatobiliary scintigraphy and evaluate its association with the expression Pglycoprotein (P-gp) in intestinal tissues.Methods A total of 12 SD rats were randomly divided into the normal control group (3 rats) and the group of common bile duct ligation (CBDL;9 rats).CBDL was used to establish the rat model of extrahepatic biliary atresia.99Tcm-MIBI hepatobiliary scintigraphy was performed at 2,3 and 4 weeks after ligation in the CBDL group and normal control group with continuous dynamic acquisition (3 min/frame) for 30 min and then delaying imaging at 30 min,1,2 and 3 h.After that,all rats were sacrificed,and the blood samples were taken out for the determination of serum ALT,AST,TBIL,DBIL,IBIL,ALP,γ-GT and TBA,and the tissues of duodenum,jejunum,ileum,colon and cecum were taken out for analyzing the expression level of P-gp by immunohistochemistry.Two-sample t test and one-way analysis of variance were used.Results Compared with the normal control group,the serum levels of ALT,AST,TBIL,DBIL,IBIL,ALP,γ-GT and TBA were significantly increasing at 2,3,4 weeks after ligation in CBDL group (t:-3.04 to-44.54,all P＜0.05).99Tcm-MIBI hepatobiliary imaging showed that there was radioactive accumulation in colon or cecum area,excluding the duodenum,jejunum and ileum area,at 3 h after intravenous injection of 99Tcm-MIBI in CBDL group.The results of immunohistochemistry showed that with the obstruction time prolonged,the expression levels of P-gp in duodenum,jejunum and ileum segments were gradually decreased (F=5.17,9.07,23.52;all P＜0.05),while the expression levels in the colon and cecum segments were not changed obviously (F=2.00,3.17;both P＞0.05).Conclusion 99Tcm-MIBI can be excreted through intestinal mucosa,and this process may be associated with P-gp expression.

OBJECTIVETo establish a labeling method for a specific lung cancer-targeting small molecule peptide cNGQGEQc with ¹³¹I and observe the radioactivity distribution of the labeled peptide in rabbits using single-photon emission computed tomography (SPECT).

METHODSChloramine-T method was used for ¹³¹I labeling of the tyrosine amino group on cNGQGEQc, and the labeling efficiency and radiochemical purity of ¹³¹I-cNGQGEQc were determined with paper chromatography. The stability of ¹³¹I-cNGQGEQc in saline and human serum was assessed after incubation in water bath at 37 degrees celsius; for 24 h. The octanol-water partition coefficient lg P (the radioactivity counting ratio of ¹³¹I-cNGQGEQc dissolved in 100 µl octanol or in 100 µl saline) was calculated. SPECT was performed in 3 male New Zealand white rabbits after intravenous injection of ¹³¹I-cNGQGEQc to observe the dynamic distribution of the peptide with the time-radioactivity curve (T-A curve) of the region of interest (ROI).

RESULTSWith a labeling efficiency of 90%, ¹³¹I-cNGQGEQc showed a radiochemical purity of was 95% after purification with HPLC. The radiochemical purity of ¹³¹I-cNGQGEQc was (93.12 ± 1.18)% and (88.34 ± 5.43)% after intubation in saline and human serum for 24 h, respectively. The octanol-water partition coefficient lg P of ¹³¹I-cNGQGEQc was -1.75, suggesting its hydrosolubility. In rabbits with intravenous injection of ¹³¹I-cNGQGEQc, SPECT visualized the kidneys at 1 min after the injection; the imaging of the heart and liver became attenuated at 5 min when the bladder was visualized with an increasing radioactivity. The radioactivity of the soft tissues began to fade at 30 min. No gallbladder visualization was detected, and the radioactivity of the abdomen remained low. No obvious radioactivity concentration was observed in the thyroid and stomach. The T-A curves of the ROI of all the tissues and organs descended over time.

CONCLUSIONRadiolabeling of cNGQGEQc with ¹³¹I is simple and highly efficient. ¹³¹I-cNGQGEQc has good stability in vitro and good distribution characteristics for in vivo imaging, and is cleared mainly by renal excretion due to its hydrosolubility. These results provide experimental basis for further studies of diagnosis and therapy of lung cancer with targeting polypeptide.

Animals ; Antineoplastic Agents ; pharmacokinetics ; Chloramines ; Humans ; Iodine Radioisotopes ; chemistry ; Lung Neoplasms ; Male ; Peptides ; pharmacokinetics ; Rabbits ; Radiopharmaceuticals ; pharmacokinetics ; Tissue Distribution ; Tomography, Emission-Computed, Single-Photon ; Tosyl Compounds

Background and objective Hypoxia is an important biological characteristics of solid tumor, it is not sensitive to radiotherapy and chemotherapy for which is the presence of hypoxic cell, thus increasing their resistance to con-ventional radiotherapy and chemotherapy, therefore, the detection of hypoxia degree of tumor tissue is of great signiifcance. hTe hypoxia imaging of nuclear medicine can relfect the degree of tissue hypoxia, which can selectively retained on the hypoxic cells or tissues, including nitroimidazole and non nitroimidazole; the nitroimidazole is widely and deeply researched as hypoxic celles developer in China and abroad at present. hTe research about application of radionuclide labelled technique has clini-cal application value to develop the hypoxia imaging agent EDTA-MN complexes which was labeled. To study the feasibility of99mTc by direct labeling method, the radiochemical properties evaluation of99mTc-EDTA-MN, and observe the distribution characteristics of99mTc radiolabeled EDTA-MN in the xenogratf lung cancer nude mice bearing non-small cell lung cancer cell (A549), and provide experimental evidence for its further research and application.MethodshTe radiolabeling of EDTA-MN with99mTc was performed with direct labeling method, respectively, on the reaction dosage (10 mg, 5 mg, 2 mg), stannous chlo-ride dosage (8 mg/mL, 4 mg/mL, 2 mg/mL), mark system pH (2, 4, 5, 6) one by one test, using orthogonal design analysis, to ifnd the optimal labeling conditions. Labelling rate, radiochemical purity, lipid-water partition coeffcient and in vitro stability in normal saline (NS) were determined by TLC and HPLC, and the preliminary study on the distribution of99mTc-EDTA-MN in nude mice.Results hTe labeling rate of99mTc-EDTA-MN with the best labeling conditions was (84.11±2.83)%, and the ra-diochemical purity was higher than 90% by HPLC puriifcation, without any notable decomposition at room temperature over a period of 12 h. hTe partition coeffcient was lgP=-3.05, indicated that this complex was hydrophilic. At 3 h post-injection, the imaging of99mTc-EDTA-MN in nude mice bearing non-small cell lung cancer cell showed that more radioactive gathered in bladder at0.5 h, the transplanted tumor was clearly imaged at 1 h post-injection, during whole imaging radioactive in other tissues and organs was low. hTe radioactivity of tumor uptake by using of ROI technology were (88.14±11.59), (123.17±9.06), (98.08±14.40) and (79.87±10.57) at 0.5, 1, 2, 3 h post-injection, and the ratio of T/NT of tumor and liver area were (1.95± 0.19), (3.58±0.78), (3.95±0.39) and (5.01±0.28), respectively.99mTc-EDTA-MN could be quickly cleared from the blood in mice primarily through the kidneys, and the radioactivity in other tissues and organs remained low.Conclusion99mTc-EDTA-MN can be easily prepared and labeled compound with high labeling rate and stability, it appears to be suitable for further experiments requirementin vivo andin vitroapplication.

OBJECTIVETo establish a two-step pretargeting approach to lymphoma radioimmunoimaging in mice using biotinynaled CD45 monoclonal antibody (McAb) and (188)Re-avidin in a tumor-bearing mouse model.

METHODSSix Nod-Scid mice bearing lymphoma cell xenograft were randomized to receive either an intravenous injection of 50 µg/200 µL biotinyled CD45 McAb followed 24 h later by an intraperitoneal injection of 3.7 MBq (50 µg/100 µL) (188)Re-avidin (two-step pretargeting group), or a single intravenous injection of 3.7 MBq (100 µg/100 µL) (188)Re-CD45 McAb (control group). SPECT was performed at 0.5, 1, 6 and 23 h post-injection to characterize (188)Re isotope biodistribution. At 24 h pos-injection, the mice were sacrificed for measurement of radioactivity uptake in the tumor and normal tissues and calculation of the tumor-to-non-tumor (T/NT) ratios.

RESULTSSPECT showed that the two-step pretargeting method resulted in a low radioactivity in the blood pool during the imaging and a concentrated radioactivity in the liver and spleen. The transplanted tumor began to be displayed at 1 h post-injection and was clearly displayed at 1-6 h; the images were clear even at 23 h. With the two-step pretargeting method, the radioactive uptake at 24 h post-injection were (1.34∓0.52)%, (6.77∓2.32)%, and (2.81∓1.25)% in the tumor, kidney and liver, respectively, with low radioactivity levels in other organs and high tumor/blood and tumor/muscle ratios (4.28∓0.82 and 8.00∓0.88, respectively). In the control group, SPECT revealed intense radioactivity in the liver, spleen, and kidneys with obscure display of the tumor; at 20 h, the radioactivity in the blood pool remained high but that in the tumor was low, and the tumor/blood and tumor/muscle ratios at 24 h were only 0.58∓0.06 and 3.21∓0.24, respectively.

CONCLUSIONCompared with (188)Re-CD45 McAb, the two-step pretargeting approach exhibits a good specificity in targeting lymphoma with an increased T/NT ratio in mice and allows early tumor display at 1 h post-injection.

Animals ; Antibodies, Monoclonal ; Avidin ; Disease Models, Animal ; Lymphoma ; diagnosis ; Mice ; Mice, Nude ; Neoplasm Transplantation ; Radioimmunodetection ; Tissue Distribution ; Tomography, Emission-Computed, Single-Photon

OBJECTIVETo develop a method for (99m)Tc radiolabeling of a small molecular peptide targeting lung carcinoma and observe the biokinetics and biodistribution of the labeled peptide in normal mice and rabbits.

METHODSMAG3-peptide (cNGQGEQc) was labeled with (99m)Tc and the labeling rate was determined with paper chromatography. In vitro stability test, cysteine challenge test and serum incubation test were performed for radiochemical evaluation of the labeled peptide. Blood (99m)Tc-peptide clearance in rabbits was evaluated by determining blood radioactive concentrations at different time points after injection of 37 MBq (99m)Tc-peptide, and its dynamic distribution was investigated by SPECT imaging. The percent injected dose per gram of tissue was calculated for each organ of mice injected intravenously with 7.4 MBq (99m)Tc-peptide based on gamma counter readings.

RESULTSThe labeling rate of (99m)Tc-peptide exceeded 90%, and the radiochemical purity was 91% after placing for 12 h at room temperature and 85% after incubation at 37 degrees celsius; with human serum. The cysteine replacement rate was less than 7%, and the binding rate of (99m)Tc-peptide with serum proteins was below 5%. SPECT imaging showed that the labeled peptide could be quickly cleared from the blood in normal animals primarily through the kidneys, and the radioactivity in other tissues and organs remained low.

CONCLUSION(99m)Tc-peptide can be easily prepared with a high labeling yield. With good stability both in vitro and in vivo, (99m)Tc-peptide can be quickly cleared from the blood and excreted though the kidney with ideal biodistribution and biokinetics in vivo.

Animals ; Humans ; Male ; Mice ; Molecular Probes ; Organotechnetium Compounds ; blood ; Rabbits ; Tomography, Emission-Computed, Single-Photon ; methods

BACKGROUND: Both aldehyde dehydrogenase 2 (ALDH2) rs671 polymorphism and lifestyle behaviors are involved in coronary artery disease (CAD), while the interaction between them is currently unknown. METHODS: A nested case-control study was conducted in 161 patients with CAD and 495 controls in dyslipidemia population in Yinzhou District, Ningbo, Zhejiang Province, China, in August 2013. Anthropometric data and blood samples were collected, demographic characteristics and lifestyle behaviors information were obtained by a face-to-face interview, dietary intake was assessed by a food frequency questionnaire, and genomic DNA was genotyped. RESULTS: Carriers with increasing number of A alleles had an elevated CAD risk compared with G allele carriers (adjusted OR = 1.483, 95% CI = 1.114-1.974). Carriers of rs671 A/G and A/A genotypes had a higher CAD risk than carriers of G/G genotype (adjusted OR = 1.492, 95% CI = 1.036-2.148). Similarly, individuals with rs671 A/A genotype had a higher CAD risk than individuals with A/G and G/G genotypes (adjusted OR = 2.161, 95% CI = 1.139-4.101). We found a borderline additive interaction between regular fried food intake and A/A and A/G genotypes, and a significantly additive interaction between sedentary/light physical activity and A/A and A/G genotypes. CONCLUSIONS Individuals with A/A or A/G genotypes of rs671 have a higher CAD risk, if they lack physical activity and take fried food regularly, than individuals with G/G genotypes. These findings can help to provide a guide to targeted heart health management.
Adult ; Aged ; Aged, 80 and over ; Aldehyde Dehydrogenase, Mitochondrial ; genetics ; Alleles ; Case-Control Studies ; China ; Coronary Artery Disease ; blood ; genetics ; Dyslipidemias ; blood ; genetics ; Female ; Genetic Association Studies ; Genetic Predisposition to Disease ; Genotype ; Humans ; Life Style ; Male ; Middle Aged ; Polymorphism, Single Nucleotide ; Risk Factors