Objective:To labelavidin(Av)or streptavidin(SA)with 153 Sm by takingadvantageof thehighbindingaffin-ityof biotinto Av or SA.Methods:A biotinderivative(DTPA-biotin)wasradiolabelledwith 153 Sm andthenboundto Av or SA.Th...Objective:To labelavidin(Av)or streptavidin(SA)with 153 Sm by takingadvantageof thehighbindingaffin-ityof biotinto Av or SA.Methods:A biotinderivative(DTPA-biotin)wasradiolabelledwith 153 Sm andthenboundto Av or SA.Thein vivo kineticsandbiodistributionof 153 Sm-labeledAv,SA andDTPA-biotinwerestudiedinratsandmice.Results:153 Sm-Avwascharacterizedby rapidclearancefromthebloodwithhighliverandrenaluptake;153 Sm-SAwas clearedfromthebloodslowlywithhighretentionintheliver,spleenandkidney,whereas 153 Sm-DTPA-biotinmetabolismwas accelerated,anditsexcretionwasmainlythroughthekidney.Conclu sion:Thebiodistributiondifferenceof SAandAvmay providean experimentalbasisfor theselectionof differentcomponentsof avidin-biotinsystemin pretagetingradioim-munoimagingandradioimmunotherapy.展开更多
AIM: To evaluate the influence of avidin chase on the side effects of radioimmunotherapy (RIT) in nude mice bearing human colon carcinoma and therapeutic outcome.METHODS: Purified anti-CEA monoclonal antibody (McAb)wa...AIM: To evaluate the influence of avidin chase on the side effects of radioimmunotherapy (RIT) in nude mice bearing human colon carcinoma and therapeutic outcome.METHODS: Purified anti-CEA monoclonal antibody (McAb)was biotinylated with NHS-biotin, and then radiolabeled with 188Re by the direct method. 188Re-labeledbiotinylated anti-CEA McAb (188Re-CEA McAb-Bt) was intravenously injected followed by intravenous injection of avidin after 24 h. SPECT imaging and biodistribution study were performed at 28-48 h after the injection of 188Re-CEA McAb-Bt. Three groups of nude mice subcutaneously grafted with human colon carcinoma were treated 7 d after the graft. Mice in the avidin chase group received intravenous injection of 188Re-CEA McAb-Bt (11.1 MBq/20 μg) followed by intravenous injection of cold avidin (80 μg) after 24 h. Mice in the control group (treated group without avidin chase) only received the injection of 188Re-CEA McAb-Bt (11.1 MBq/20 μg), another control group (non-treated group) only received 0.1 mL normal saline solution. Toxicity was evaluated on the basis of change of body weight and peripheral WBC counts, and therapy effects were determined by variation in tumor volume. Histological analysis of tumors was also performed.RESULTS: Avidin chase markedly accelerated the clearance of 188Re-CEA McAb-Bt from the blood and normal tissues. The tumor uptakes of 188Re-CEA Mc Ab-Bt at 28 h were 5.90 and 6.42% ID/g, respectively, in chase group and in non-chase group, while the tumor-to-background (T/NT) ratios were 3.19 and 0.56, respectively. The tumor uptake was slightly decreased by avidin chase, but the T/NT ratios were increased. In treated groups the growth rate of body weight and the number of WBC decreased after injection of 188Re-CEA McAb-Bt, and the WBC counts recovered earlier in the group with avidin chase than in the group without avidin chase. Compared to the nontreated group, treated groups with and without avidin chase showed significant anti-tumor effects.CONCLUSION: Avidin chase can effectively reduce the side effects of RIT, and improve therapeutic efficacy.展开更多
In this work an impedimetric immunosensor based on affinity immobilization method of a biotin labelled anti-human IgG antibody, used as a model system, was reported. The experimental procedure involves the growth of a...In this work an impedimetric immunosensor based on affinity immobilization method of a biotin labelled anti-human IgG antibody, used as a model system, was reported. The experimental procedure involves the growth of a self-assembled monolayer of a thiol (cysteamine) carrying terminal amine groups on gold electrodes. Glutarardehyde, a homobifunctional cross-linker, was used as a coupling reagent for the covalent linking of avidin to the amine groups of cysteamine. The attachment of the biotin labeled antibodies (anti-Human IgG) to the subsequent modified gold electrode was achieved by affinity interactions tacking advantage of the strong avidin-biotin bridge. The stepwise assembly process of the electrode was interrogated by means of cyclic voltammetry, electrochemical impedance spectroscopy and contact angle measurements. The response of the antibody modified electrode to their target antigens was investigated in the presence of BSA (bovin serum albumin) in order to alleviate non-specific adsorption problems. A proposed electrical model was used to analyse the experimental data. The resulting immunosensor has a linear dynamic range of 100 - 900 ng?ml<sup>–</sup>1 of antigen and a detection limit of 100 ng?ml<sup>–</sup>1.展开更多
Background: In this study, we aimed to evaluate the benefit of performing of tonsillectomy in patients with raised serum ASO titre only in absence or presence of group A beta heamolytic streptococci (GABHS) in throat ...Background: In this study, we aimed to evaluate the benefit of performing of tonsillectomy in patients with raised serum ASO titre only in absence or presence of group A beta heamolytic streptococci (GABHS) in throat swab. Materials and methods: In this prospective cohort study, 196 patients below the age of 14 were suffering from non-specific streptococcal infections, without fulfilling the clinical parameters used for the diagnosis of chronic tonsillitis 156 patients had a raised ASO titre above 200 iu/ml. Throat swab culture was performed in all patients. Results: The results showed that out of the 156 patients, 52 had positive throat swab for GABHS. All of the patients underwent tonsillectomy. Follow-up of the patients for one year after the operation, 88% of the first group with high ASO titre and positive throat swab showed improvement of symptoms;25% of the second group with high ASO titre and negative throat swab showed improvement of symptoms. Conclusion: Our study shows that isolation of GABHS from the patients tonsils by throat swab along with high ASO titre may be an indication of tonsillectomy in absence of any other indications.展开更多
文摘Objective:To labelavidin(Av)or streptavidin(SA)with 153 Sm by takingadvantageof thehighbindingaffin-ityof biotinto Av or SA.Methods:A biotinderivative(DTPA-biotin)wasradiolabelledwith 153 Sm andthenboundto Av or SA.Thein vivo kineticsandbiodistributionof 153 Sm-labeledAv,SA andDTPA-biotinwerestudiedinratsandmice.Results:153 Sm-Avwascharacterizedby rapidclearancefromthebloodwithhighliverandrenaluptake;153 Sm-SAwas clearedfromthebloodslowlywithhighretentionintheliver,spleenandkidney,whereas 153 Sm-DTPA-biotinmetabolismwas accelerated,anditsexcretionwasmainlythroughthekidney.Conclu sion:Thebiodistributiondifferenceof SAandAvmay providean experimentalbasisfor theselectionof differentcomponentsof avidin-biotinsystemin pretagetingradioim-munoimagingandradioimmunotherapy.
基金Supported by the China Postdoctoral Science Foundation, No. 2003033345Medical Sciences and Technology Foundation of Guangdong Province, No.A2000389
文摘AIM: To evaluate the influence of avidin chase on the side effects of radioimmunotherapy (RIT) in nude mice bearing human colon carcinoma and therapeutic outcome.METHODS: Purified anti-CEA monoclonal antibody (McAb)was biotinylated with NHS-biotin, and then radiolabeled with 188Re by the direct method. 188Re-labeledbiotinylated anti-CEA McAb (188Re-CEA McAb-Bt) was intravenously injected followed by intravenous injection of avidin after 24 h. SPECT imaging and biodistribution study were performed at 28-48 h after the injection of 188Re-CEA McAb-Bt. Three groups of nude mice subcutaneously grafted with human colon carcinoma were treated 7 d after the graft. Mice in the avidin chase group received intravenous injection of 188Re-CEA McAb-Bt (11.1 MBq/20 μg) followed by intravenous injection of cold avidin (80 μg) after 24 h. Mice in the control group (treated group without avidin chase) only received the injection of 188Re-CEA McAb-Bt (11.1 MBq/20 μg), another control group (non-treated group) only received 0.1 mL normal saline solution. Toxicity was evaluated on the basis of change of body weight and peripheral WBC counts, and therapy effects were determined by variation in tumor volume. Histological analysis of tumors was also performed.RESULTS: Avidin chase markedly accelerated the clearance of 188Re-CEA McAb-Bt from the blood and normal tissues. The tumor uptakes of 188Re-CEA Mc Ab-Bt at 28 h were 5.90 and 6.42% ID/g, respectively, in chase group and in non-chase group, while the tumor-to-background (T/NT) ratios were 3.19 and 0.56, respectively. The tumor uptake was slightly decreased by avidin chase, but the T/NT ratios were increased. In treated groups the growth rate of body weight and the number of WBC decreased after injection of 188Re-CEA McAb-Bt, and the WBC counts recovered earlier in the group with avidin chase than in the group without avidin chase. Compared to the nontreated group, treated groups with and without avidin chase showed significant anti-tumor effects.CONCLUSION: Avidin chase can effectively reduce the side effects of RIT, and improve therapeutic efficacy.
文摘In this work an impedimetric immunosensor based on affinity immobilization method of a biotin labelled anti-human IgG antibody, used as a model system, was reported. The experimental procedure involves the growth of a self-assembled monolayer of a thiol (cysteamine) carrying terminal amine groups on gold electrodes. Glutarardehyde, a homobifunctional cross-linker, was used as a coupling reagent for the covalent linking of avidin to the amine groups of cysteamine. The attachment of the biotin labeled antibodies (anti-Human IgG) to the subsequent modified gold electrode was achieved by affinity interactions tacking advantage of the strong avidin-biotin bridge. The stepwise assembly process of the electrode was interrogated by means of cyclic voltammetry, electrochemical impedance spectroscopy and contact angle measurements. The response of the antibody modified electrode to their target antigens was investigated in the presence of BSA (bovin serum albumin) in order to alleviate non-specific adsorption problems. A proposed electrical model was used to analyse the experimental data. The resulting immunosensor has a linear dynamic range of 100 - 900 ng?ml<sup>–</sup>1 of antigen and a detection limit of 100 ng?ml<sup>–</sup>1.
文摘Background: In this study, we aimed to evaluate the benefit of performing of tonsillectomy in patients with raised serum ASO titre only in absence or presence of group A beta heamolytic streptococci (GABHS) in throat swab. Materials and methods: In this prospective cohort study, 196 patients below the age of 14 were suffering from non-specific streptococcal infections, without fulfilling the clinical parameters used for the diagnosis of chronic tonsillitis 156 patients had a raised ASO titre above 200 iu/ml. Throat swab culture was performed in all patients. Results: The results showed that out of the 156 patients, 52 had positive throat swab for GABHS. All of the patients underwent tonsillectomy. Follow-up of the patients for one year after the operation, 88% of the first group with high ASO titre and positive throat swab showed improvement of symptoms;25% of the second group with high ASO titre and negative throat swab showed improvement of symptoms. Conclusion: Our study shows that isolation of GABHS from the patients tonsils by throat swab along with high ASO titre may be an indication of tonsillectomy in absence of any other indications.