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<p><b>BACKGROUND</b>Monoclonal antibodies (mAbs) such as DD3, raised against progastrin-releasing peptide(31-98) (ProGRP (31-98)) antigen, have been used to target small cell lung cancer (SCLC). However, as an intact mAb, DD3 is cleared slowly from the body, with an optimal radioimmunoimaging time of 72 hours. More recently, a single-chain antibody fragment has demonstrated reduced excretion time in blood and normal tissues and is increasingly used in diagnostic cancer research. Thereby, it potentially increases the radioimmunoimaging efficacy. However, there have been few studies with this antibody fragment. The aim of this study was to characterize the preliminary radioimmunoimaging and biodistribution of (131)I-anti-ProGRP(31-98) scFv in nude mice bearing SCLC xenografts.</p><p><b>METHODS</b>Anti-ProGRP(31-98) scFv was used to detect ProGRP expression by flow cytometry analysis and immunohistochemistry. (131)I-anti-ProGRP(31-98) scFv was injected intravenously into healthy Kunming mice and the percentage injected dose per gram (%ID/g) in various organs was calculated. Similarly, the %ID/g and tumor/non-tumor ratio in xenograft-bearing mice was calculated. After injection of (131)I-anti-ProGRP(31-98) scFv, treated mice were imaged at 1, 24, and 30 hours. Then the tumor/base ratios were calculated.</p><p><b>RESULTS</b>ProGRP was highly expressed in NCI-H446 cells and xenograft tissue. The metabolism of (131)I-anti-ProGRP(31-98) scFv in healthy mice was consistent with a first-order and two-compartment model; T1/2α and T1/2β were 10.2 minutes and 5 hours 18 minutes, respectively. The %ID/g of (131)I-anti-ProGRP(31-98) scFv in xenografts was much higher than in healthy tissues at 12 hours after injection, reaching a maximum of (5.38±0.92) %ID/g at 24 hours. Successful imaging of xenograft tissue was achieved as early as 1 hour post-injection and persisted until 30 hours, with 24 hours proving optimal.</p><p><b>CONCLUSION</b>(131)I-anti-ProGRP(31-98) scFv shows highly selective tumor uptake with low accumulation in normal tissues and rapid blood clearance, indicating that it could be a promising agent for SCLC radioimmunoimaging.</p>
Subject(s)
Animals , Female , Humans , Male , Mice , Flow Cytometry , Immunoglobulin Fragments , Allergy and Immunology , Mice, Inbred BALB C , Mice, Nude , Peptide Fragments , Allergy and Immunology , Radioimmunodetection , Methods , Recombinant Proteins , Allergy and Immunology , Small Cell Lung Carcinoma , Diagnostic Imaging , Metabolism , Xenograft Model Antitumor AssaysABSTRACT
Objective To explore the clinical value of dual-phase 99Tcm-MIBI scintigraphy in the localization and diagnosis of secondary hyperparathyroidism (SHPT).Methods A total of 20 patients (8 males,12 females; average age 49.6 years) with uremic SHPT who underwent parathyroidectomy from 2010 to 2013 were retrospectively analyzed.All patients underwent 99Tcm-MIBI SPECT/CT and 19 underwent color Doppler ultrasonography (CDUS).Post-excisional histopathology was considered as the gold standard.The diagnostic efficacies of 99Tcm-MIBI and CDUS for SHPT were calculated.The correlation between T/NT ratio in delayed imaging and the volume of excised parathyroid and the intact PTH (iPTH) were analyzed.x2 test,Pearson or Spearson correlation analysis were used to analyze the data.Results The sensitivity,specificity,positive predictive value,negative predictive value and accuracy of 99Tcm-MIBI SPECT/CT and CDUS in the diagnosis of SHPT were 66.67％ (44/66),100％(14/14),100％ (44/44),38.89％(14/ 36),72.50％ (58/80) and 78.19％(43/55),52.38％(11/21),81.13％(43/53),47.83(11/23),71.05％ (54/76),respectively.There were significant differences in specificity and positive predictive value (x2 =9.33,9.26,both P＜0.05),but no significant differences in the sensitivity,negative predictive value and accuracy (x2 =1.97,0.04,0.46,all P＞0.05).T/NT ratio correlated with serum iPTH and parathyroid volume (r=0.638,rs =0.571,both P＜0.05).Conclusions The specificity of 99Tcm-MIBI SPECT/CT is superior to CDUS in the diagnosis of SHPT.Dual-phase 99Tcm-MIBI SPECT/CT could locate the hyperfunctional parathyroid gland and provide the basis for surgical treatment.
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ObjectiveTo study the biologic distribution of 131I-Herceptin in BALB/c-neu nude mice bearing HER-2 positive SK-BR-3 human breast cancer xenografts and the radioimmunoimaging characteristics of nude mouse bearing human SK-BR-3 breast cancer xenografts. MethodSK-BR-3 breast cancer cells were implanted subcutaneously to athymic mice to establish animal model.Tumor bearing mice were continuously imaged with SPECT. The radiocounting per minute (cpm) of different organ on a γ-arithmometer was measured at 4,12,24,48 h postinjection of 131I-Herceptin or 131I-mlgG,and the T/NT ratios and the uptake percentages per gram of the injection dose (％ ID/g) was gained. ResultsModel was established in 96％ nude mouse.Compared with the control group,there was a significantly stronger contrast enhancement of tumor imaging,bigger T/NT and ％ ID/g in experimental group ( P ＜ 0.0l ).Conclusions 131I-Herceptin concentrates obviously in implanting tumor tissues of nude mouse,hence it is a good radiopharmaceutical agent targeting SK-BR-3 xenografts.
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Objective To explore the effect of purification on monoclonal antibody (MAb) against PGRP by Protein A-Sepharose affinity chromatography, and to provide some based data for the purification of other antibody using the same method. Methods The ascites which include MAb was purified by Protein A-Sepharose affinity chromatography. The purity and activity of MAb was tested by SDS-PAGE and ELISA. The biological function was identified by flow cytometer and immunohistochemistry. Results The average concentration of protein in ascites before purification is 23.62 mg/ml. Before and after purification, the total protein is 148.79 mg and 146.67 mg, respectively. The recovery coefficient of protein is 98.58%. The concentration of MAb in ascites is 5.21 mg/ml averagely. The MAb purity is more than 95 %. The immunoactivity of purified antibody is higher than that of unpurified antibody. Conclusion The purity of MAb against PGRP purified by Protein A-Sepharose affinity chromatography is very high. The immunoactivity of purified antibody is higher than that of unpurified antibody. So the ProteinA-Sepharose affinity chromatography is a rapid, convenient and reliable method for the purification of MAb Against PGRP.
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<p><b>OBJECTIVE</b>To injvestigate the cerebral blood flow of patients with early syphilis.</p><p><b>METHODS</b>(99)Tc(m)-ECD as brain perfusion imaging agent was used in single photon emission computed tomography (SPECT) for 32 patients with early syphilis and 15 controls. Visual analyses were made on every BSPECT image.</p><p><b>RESULTS</b>The 32 patients with early syphilis had general, patchy hypoperfusion of cerebral blood flow. Fourteen of the 32 patients had 48 episodes of marked patchy hypoperfusion of rCBF. The responsible areas of hypoperfusion in a patchy distribution involved the left frontal lobe (6 episodes), right frontal lobe (3), left parietal lobe (7), right parietal lobe (6), left temporal lobe (11), right temporal lobe (5), left occipital lobe (3), left basal ganglia (3), cerebellum (1), and nerve nuceus (1). No abnormality was found in the control group.</p><p><b>CONCLUSIONS</b>Cerebral blood flow abnormalities exist in patients with early syphilis. General patchy hypoperfusion on SPECT imaging is common.</p>
Subject(s)
Adult , Humans , Middle Aged , Brain , Diagnostic Imaging , Cerebrovascular Circulation , Physiology , Regional Blood Flow , Syphilis , Diagnostic Imaging , Tomography, Emission-Computed, Single-PhotonABSTRACT
Objective:To label monoclonal anti-GPⅢa antibody (SZ21) with 99 Tcm and evaluate the value of 99 Tcm-SZ-21 for detecting thrombi in vivo.Methods:SZ-21 was modified with 2-iminotholane and labeled with 99 Tcm-GH and radiochemical purity was determined by ITLC-SG.99Tcm-SZ-21 was injected via ear edge vein in 5 rabbits in which thrombi were induced in the right femoral arteries.As control,99 Tcm-GH was administered in 1 rabbit.Static images were acquired and irregularly shaped ROIs were drawn on the images to calculate the ratios of T/M and T/B.Vein blood was drawn at 2 min,5 min,10 min,30 min and 1 h-3 h after injection in 2 rabbits so as to observe the blood clearance of 99 Tcm-SZ-21.Rabbits were sacrificed after 3 h of imaging.The vessels including clots were harvested and imaged.Cardiac muscle,liver,spleen,lung,kidney,etc.were excised and weighed.Radioactivity counts were measured to calculate % ID/g.Results:The radiochemical purity of 99 Tcm-SZ21 was beyond 90% and stable in vitro.Thrombi could be visualized at 30 min after injection,and at 2 h image of thrombi was clearly visualized,T/M (2.55?0.72) and T/B (1.94?0.51) ratios were high.In vitro imaging showed that T/B was 4.43?1.5.Conclusion:99Tcm-SZ-21 could be a potential agent for imaging diagnosis of thrombotic disease.