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1.
Jesus LM Abreu PR Almeida MC Brito LC Soares SF de Souza DE Bernardo LC Fonseca AS Bernardo-Filho M 《Acta biologica Hungarica》2006,57(2):191-200
Since ancient times propolis has been employed for many human purposes because to their favourable properties. Blood constituents labeled with technetium-99m (99mTc) have been used in nuclear medicine procedures. Some authors have reported that synthetic or natural drugs can interfere with the labeling of blood constituents with 99mTc. The aim of this work was to evaluate the action of a propolis extract on the labeling of blood elements with 99mTc. Samples of whole blood of male Wistar rats were incubated in sequence with an aqueous propolis extract at different concentrations, stannous chloride and 99mTc, as sodium pertechnetate. Blood samples were centrifuged to separate plasma and blood cells, soluble and insoluble fractions of plasma and blood cells were also separated after precipitation in trichloroacetic acid solution and centrifugation. The radioactivity was counted and the percentage of incorporated radioactivity (%ATI) for each fraction was calculated. The data obtained showed that the aqueous propolis extract used decreased significantly the %ATI in plasma proteins at higher concentration studied. Results suggest that at high concentration the constituents of this extract could alter the labeling of plasma proteins competing with same binding sites of the 99mTc on the plasma proteins or acting as antioxidant compounds. 相似文献
2.
Acetylsalicylic acid is the most widely used drug as antipyretic, analgesic, anti-inflammatory agent and for secondary prevention of thrombotic phenomena in the heart, brain and peripheral circulation. Drugs can modify the labeling of blood constituents with technetium-99m (99mTc). This work has evaluated the effect of in vivo treatment with acetylsalicylic acid on the in vitro labeling of the blood constituents with 99mTc. Wistar rats were treated with different doses (1.5, 3.0 and 6.0 mg/kg) of acetylsalicylic acid during 1 hour. At higher dose used (6.0 mg/kg) animals were treated during different period of time (0.25, 1.0 and 4.0 hours). Animals treated with physiologic saline solution were used as control. After the labeled process; plasma (P), blood cells (BC), insoluble (IF-P, IF-BC) and soluble (SF-P, SF-BC) fractions were separated. Afterwards, the percentage of radioactivity (%ATI) in each fraction was calculated. The treatment during 1 hour with acetylsalicylic acid at higher dose has significantly (p < 0.05) modified the fixation of 99mTc on blood cells. Considering the results, we suggest that acetylsalicylic acid used at therapeutic doses may interfere with the nuclear medicine procedures related to these blood constituents. 相似文献
3.
Acetaminophen (AAP), acetylsalicylic acid (ASA) and dipyrone (DIP) are antipyretic and analgesics drugs that have wide use in health sciences. Some drugs can modify the labeling of blood elements with technetium-99m (99mTc). This work has evaluated the effect of AAP, ASA and DIP on the labeling of the blood elements with 99mTc. Blood was incubated with different concentrations of the drugs before the 99mTc-labeled process. Plasma (P), blood cells (BC), insoluble (IF-P, IF-BC) and soluble (SF-P, SF-BC) fractions were separated and percentage of radioactivity (%ATI) in each fraction was determined. Data have shown that the antipyretic drugs used in this study did not significantly modify the fixation of 99mTc on the blood elements when the experiments were carried out with the doses usually used in human beings. Although the experiments were carried out with rats, it is possible to suggest that AAP, ASA or DIP should not interfere with the procedures in nuclear medicine involving the labeling of blood elements with 99mTc. 相似文献
4.
P V S Z Capriles A P M Dias T E M M Costa M B N Oliveira M V C Faria E G Moura B A L Abreu M Bernardo-Filho 《Cellular and molecular biology, including cyto-enzymology》2002,48(7):771-776
The use of eggplant has been suggested to treat different diseases. We studied the effect of eggplant extract on the labeling of red blood cells (RBC) and plasma proteins with technetium-99m (Tc-99m) and on biodistribution of sodium pertechnetate (Tc-99m) in rats. Blood was incubated with an eggplant extract (final concentrations 3.12 to 250.00 mg/ml) for 60 min. Then, stannous chloride (SnCl2) (0.06 or 1.2 microg/ml) and Tc-99m, as sodium pertechnetate, were added. Samples of RBC and plasma (P) were separated and also precipitated and soluble (SF) and insoluble (IF) fractions were isolated. The percent of radioactivity (%ATI) in the fractions was calculated. In the biodistribution study, Wistar rats were treated with eggplant extract (300 mg/ml) for 4 weeks, in drinking water. Tc-99m was administered in the rats, after 90 min they were sacrificed and organs and blood were isolated. When 0.06 microg/ml SnCl2 was used, eggplant extract: i/ inhibited the label of RBC (97.14 +/- 2.01 to 52.21 +/- 3.97%ATI), ii/ decreased the labeling in IF-P from 38.79 +/- 11.73 to 5.49 +/- 2.65%ATI, and iii/ diminished the labeling in IF-RBC from 90.04 +/- 2.65 to 46.17 +/- 9.49%ATI. This inhibitory effect was not observed with SnCl2 1.2 microg/ml. In the biodistribution study, the %ATI: i/ increased in the liver from 2.15 +/- 0.54 to 3.11 +/- 1.29 and ii/ in the other organs the Tc-99m uptake was not modified. The uptake of Tc-99m in red blood cells protein (IF-RBC) decreased from 66.62 +/- 19.67 to 31.66 +/- 8.84%. It is possible to suggest that some components of the eggplant extract present an oxidation power able to alter the fixation of the Tc-99m on the blood elements. Moreover, as eggplant is metabolized in the liver, this fact could justify the alteration of the uptake in this organ. 相似文献
5.
Gláucio Diré Feliciano Elaine Alves Correia Lima Mario José dos Santos Pereira Márcia Betania Nunes de Oliveira Silvana Ramos Farias Moreno Deise Mara Machado de Mattos Roberto Levi Jales Mario Bernardo-Filho 《Cellular and molecular biology, including cyto-enzymology》2002,48(7):751-755
Sechium edule (chayotte) is used as food or as medication in popular medicine. The labeling of blood elements with technetium-99m (99mTc) has been altered by drugs (synthetic and natural). Some authors have reported biological effects concerning the chayotte. We have evaluated the influence of chayotte extracts (macerated and infusion) on the labeling of blood elements with 99mTc. In vitro study, blood was incubated with the extracts, (6.25, 12.5, 25, 50 and 100% v/v). In in vivo study, the animals were treated with the extracts (100% v/v), as drinking water (15 and 60 days) and samples of blood were withdrawn. The blood samples were incubated with stannous chloride and with 99mTc. Plasma (P) and blood cells (BC) were isolated, also precipitated with trichloroacetic acid and soluble (SF) and insoluble fractions (IF) separated. There was a (p < 0.05) decrease in the radioactivity in BC, IF-BC and IF-P with the infusion (100%) and a slight decrease in the uptake of 99mTc by BC and a strong decrease in the fixation in IF-P with the macerated when the extracts were administrated in vivo (15 days). In 60 days, there was a decrease in BC (98.77 to 53.53%), in IF-BC (90.36 to 21.20%) and in IF-P (77.20 to 11.01%). In vitro study no alterations on the labeling of blood elements were found, however, we have found alterations on the fixation of 99mTc in the in vivo study, probably, due to the metabolization of chayotte capable to induce the generation of active metabolites. 相似文献
6.
Liu L Xiang K Zheng T Zhang R Li M Wang Y Lu H Li J 《Molecular and cellular biochemistry》2003,247(1-2):121-126
The labeling of red blood cells with technetium-99m(99mTc) depends on a reducing agent and stannous ions, as chloride or fluoride, are widely utilized. This labeling may also be altered by drugs. Moreover, some authors have reported that the survival of Escherichia coli (E. coli) cultures decreases in presence of stannous ions. Phytic acid is present in the daily diet and we evaluated its influence on: (i) the labeling of blood elements with 99mTc and (ii) on the survival of an E. coli strain treated with stannous fluoride. Heparinized whole blood was withdrawn from Wistar rats and it was incubated with stannous chloride and with 99mTc, as sodium pertechnetate, centrifuged and plasma (P) and blood cells (BC) were isolated. Samples of P and BC were also precipitaded with trichloroacetic acid, centrifuged and soluble (SF) and insoluble fractions (IF) isolated. E. coli culture was treated with stannous fluoride in presence of phytic acid. As phytic acid altered the fixation of 99mTc on BC, on IF-P and on IF-BC and, moreover, it abolished the lethal effect of stannous fluoride on the E. coli culture, we can suggest that, probably, phytic acid would have chelating properties to the stannous ions. 相似文献
7.
Flávio Nigri Márcia B N Oliveira Mário Bernardo-Filho 《Cellular and molecular biology, including cyto-enzymology》2002,48(7):793-801
It is estimated that about 2.5 million people only in the United States are affected by epilepsy. Labelled red blood cells (RBC) and plasma proteins (PP) are used for several evaluations in nuclear medicine and drugs affecting those labelings have previously been described. The aim of this study was to evaluate whether the most popular antiseizure drugs interfere with the 99mTc labeling process of RBC and PP. Heparinized blood withdrawn from Wistar rats was incubated with phenobarbital (0.2, 2, 20, 200, 2,000 microg/ml), phenytoin (0.15, 1.5, 15, 150, 1,500 microg/ml), carbamazepine (0.7, 7, 70 microg/ml), clonazepam (0.5, 5, 50, 500 microg/ml) or valproic acid (0.5, 5, 50, 500 microg/ml) for I hr. Stannous chloride (SnCl2), in two different concentrations (0.012 or 1.2 microg/ml) and 99mTc were added. Plasma and cellular fractions were isolated by centrifugation, soluble and insoluble fractions were separated by trichloroacetic acid precipitation. The percentage of radioactivity was calculated for each fraction. Statistical analysis was performed with ANOVA and Dunnet tests. The analysis of the results has shown that phenobarbital (2,000 microg/ml) and clonazepam (50 microg/ml) significantly have reduced the RBC labeling efficiency when it was used the optimal SnCl2 concentration (1.2 microg/ml) and clonazepam (5, 50 microg/ml) has significantly decreased the PP labeling efficiency with 99mTc. Phenytoin (1,500 microg/ml) has decreased the RBC labeling efficiency when the experiments were carried out with a small SnCl2 concentration (0.012 microg/ml). We can suggest that with this in vitro assay, at the therapeutic level of phenytoin, phenobarbital, carbamazepine and valproic acid will not interfere on the 99mTc labeling process of RBC. Interference is displayed at higher phenobarbital concentrations (2,000 microg/ml). However, humans do not tolerate this concentration. On the other hand, a decreased RBC and PP labeling efficiency with 99mTc may be expected for clonazepam at therapeutic levels. 相似文献
8.
《International journal of radiation applications and instrumentation. Part B, Nuclear medicine and biology》1987,14(1):63-67
To investigate the labeling of small molecules with 99mTc by the bifunctional chelate approach, we have synthesized both a fatty acid and an estrone derivative containing a chelator of the N2S2 type. In the case of the fatty acid, this was a diaminodithiol (DADT) while for the estrone, a diaminodisulfide (DADS) was attached. The estrone derivative (5-(2-methylene estrone 3-methyl ether)-3,3,10,10-tetramethyl-1, 2-dithia-5,8-diazacyclodecane hydrochloride, DADS-E) was prepared by alkylation of DADS while the fatty acid derivative (N-(11-undecanoic acid)-N,N′-bis(2-methyl-2-mercaptopropyl) ethylenediamine hydrochloride, DADT-FA) was synthesized by alkylation of DADS followed by reduction. DADS-E was labeled in ethanol at elevated temperatures while DADT-FA was labeled at room temperature, both by stannous reduction. Paper chromatography showed both to be labeled and reverse-phase HPLC showed multiple peaks for both. Serum stability studies were performed by incubation at 37 °C with aliquots removed at 1 min and 1 day for analysis by size-exclusion HPLC. Initially, little pertechnetate or binding to serum proteins was observed whereas after 1 day the majority of activity in both cases was protein bound with 20 and 38% pertechnetate appearing for DADT-FA and DADS-E respectively. In conclusion, small biologically active molecules may be labeled with 99mTc through an attached diaminodithiol or diaminodisulfide group. 相似文献
9.
J. F. Oliveira A. C. Braga A. S. Avila L. M. Fonseca B. Gutfilen M. Bernardo-Filho 《The Yale journal of biology and medicine》1996,69(6):489-494
Thuya occidentalis is used in popular medicine in the treatment of condyloma and has antibacterial action. Red blood cells (RBC) labeled with technetium-99m (99mTc) are used for several evaluations in nuclear medicine. This labeling depends on a reducing agent, usually stannous ion. Any drug which alters the labeling of the tracer could be expected to modify the disposition of the radiopharmaceutical. We have evaluated the influence of T. occidentalis extract on the labeling of RBC and plasma proteins with 99mTc. Blood was withdrawn and incubated with T. occidentalis (0.25; 2.5; 20.5; and 34.1 percent v/v). Stannous chloride (1.2 micrograms/ml) was added and then 99mTc was added. Plasma (P) and blood cells (BC) were isolated, also precipitated with trichloroacetic acid and soluble (SF) and insoluble fractions (IF) separated. The analysis of the results shows that there is a decrease in radioactivity (from 97.64 to 75.89 percent) in BC with 34.1 percent of the drug. In the labeling process of RBC with 99mTc, the stannous and pertechnetate ions pass through the membrane, so we suggest that the T. occidentalis effect can be explained (i) by an inhibition of the transport of these ions, (ii) by damage in membrane, (iii) by competition with the cited ions for the same binding sites, or (iv) by possible generation of reactive oxygen species that could oxidize the stannous ion. 相似文献
10.
11.
《International journal of radiation applications and instrumentation. Part B, Nuclear medicine and biology》1992,19(6):607-609
Monoclonal antibodies can be labelled with technetium-99m by prereduction of the antibody with 2-mercaptoethanol, then reduction of pertechnetate with an aliquot of a stannous kit, resulting in > 97% labelling without the need for further purification. The present work shows that equally high labelling can be obtained with a variety of weak ligands and that the optimum quantity of stannous chloride is 2–4 μg. Although the label was stable to challenge with excess DTPA, cysteine was able to remove a portion of the label. We have also shown that this technique works with the IgG2a isotype in addition to the previously reported IgG1 isotype. This approach is simple, convenient and reproducible, and warrants further clinical evaluation. 相似文献
12.
马缨丹叶片水提物与挥发油的生物活性及化学成分研究 总被引:13,自引:0,他引:13
研究了马缨丹 ( Lantana camara L.)叶片水提物和挥发油水溶液的化感作用。结果表明 ,马缨丹叶片水溶物浓度在 0 .2 5 g FW m L- 1时 ,对所有受试植物的幼苗生长均有一定的抑制作用 ,浓度降至 0 .1 0 g FWm L- 1时 ,其抑制作用显著降低 ;马缨丹叶片挥发油水溶液在浓度为 1 0 0、2 0 0、30 0 μg m L- 1时 ,对受试植物均有很强的抑制作用 ,且具有明显的浓度效应。采用 GC/MS分析了马缨丹叶片挥发油的化学成分 ,鉴定了 1 9种化感物质 ,其中α-子丁香烯和β-子丁香烯为主要物质 ,分别占挥发油含量的 1 6 .2 9%、2 2 .2 9%。 相似文献
13.
马缨丹抑菌试验研究 总被引:2,自引:0,他引:2
目的:研究马缨丹的体外抑菌效果。方法:制备马缨丹水煎煮液和乙醇提取液,测定其对枯草芽孢杆菌、大肠杆菌和金黄色葡萄球菌的抑菌圈直径、最小抑菌浓度及灭菌前后提取液抑菌效果的变化。结果:当两种提取液生药含量大于0.4 g/mL时,它们对三种细菌的抑菌效果依次为:枯草芽孢杆菌〉金黄色葡萄球菌〉大肠杆菌。马缨丹乙醇提取液对三种细菌的最小抑菌浓度分别为1/64g/mL1、/16g/mL和1/32g/mL,都比水煎煮液的结果1/32g/mL、1/8g/mL和1/16g/mL低。两种提取液经121℃高压蒸汽灭菌处理后对枯草芽孢杆菌和金黄色葡萄球菌的抑制作用有所增强。结论:两种提取液对三种细菌均有不同程度的抑制作用,因此,马缨丹可考虑用于食品、化妆品及饲料防腐等领域,以提高产品质量。 相似文献
14.
《International journal of radiation applications and instrumentation. Part B, Nuclear medicine and biology》1987,14(6):555-561
Previously we investigated the use of DTPA-coupled proteins to simplify labeling with 99mTc but especially to improve the stability of the label. These investigations have now been extended to include several N2S2 ligands such as N,N′-bis(2-methyl-2-mercaptopropyl)ethylenediamine (DADT) and a novel ligand of similar structure with a propylene bridge between two amines, 2-hydroxy-N,N′-bis(2-methyl-2-mercaptopropyl)propylenediamine (DADT-3C-2OH). The condition of labeling of free ligand (pH, buffer and tin concentration) was optimized to provide 100% chelation with 99mTc at reasonable ligand concentrations (100 μg/mL or less). Labeling was determined by paper chromatography, reverse-phase and size-exclusion HPLC. After incubation in fresh serum, 37 °C for 24 h, repeat analysis showed less than 5% dissociation of the chelate. By contrast, the DTPA chelate shows instability towards oxidation during this period. DADT derivatized on an ethylene carbon showed almost identical serum stability as DADT itself whereas when derivatized on a nitrogen greater instabilities were apparent. Using identical labeling conditions, free DADT was chelated in the presence of IgG at different ligand: protein molar ratios. Non-specific binding of 99mTc to IgG at a 10:1 DADT-HM:IgG molar ratio was as little as 5% and was essentially zero at a 2:1 DADT:IgG molar ratio when labeling was by transcomplexation from 99mTc-EDTA. The DADT-3C-2OH ligand showed superior performance both in regard to serum stability and the absence of non-specific binding. In conclusion, the N2S2 ligands form more stable chelates with 99mTc than does DTPA with reduced non-specific binding and may therefore represent an attractive alternative for labeling proteins with 99mTc by the bifunctional chelate approach. 相似文献
15.
Moreno SR Arnobio A De Carvalho JJ Nascimento L Oliveira Timoteo M Olej B Rocha EK Pereira M Bernardo-Filho M Caldas LQ 《Biological research》2007,40(2):131-135
The radiobiocomplexes labeled with technetium-99m (Tc-99m) have been widely used in nuclear medicine in single photon emission computed tomography and in basic research. The aim of this study was to assess the influence of a Nectandra membranacea extract on the bioavailability of the sodium pertechnetate (Na(99m)TcO(4)) radiobiocomplex in rat organs. The animals were treated with a N. membranacea extract (30 mg/ ml), for 6 days. Na(99m)TcO(4) was injected, the organs were isolated and weighed, and the radioactivity was determined in each organ (%ATI/organ). The %ATI/organ was divided by the mass of each organ to calculate the %ATI/g. A significant increase of the %ATI/organ of Na(99m)TcO(4) was observed in muscle and thyroid as well as in the %ATI/g in the heart, kidney and thyroid. These findings could result from the interaction between components of the plant extract and the radiobiocomplex which may influence the uptake Na(99m)TcO(4) in rat organs. Therefore, precaution is suggested in the interpretation of nuclear medicine results in patients using this herb. 相似文献
16.
M B N Oliveira A S Fonseca M Bernardo-Filho R Santos 《Cellular and molecular biology, including cyto-enzymology》2002,48(7):767-769
Amantadine (AMA) has been described as dopamine stimulant and norepineprhine release, capable to block the N-methyl-D aspartate (NMDA) glutamatergic and nicotinic receptors, enhancing the sexual behavior of the male rats and inducing hypersexuality in humans. The use of technetium-99m (99mTc) can be justified for its physical and chemical properties. The aim of this study was to label and evaluate the bioavailability of the AMA labelled with 99mTc (99mTc-AMA) in Wistar female rats. The solution of 99mTc-AMA was administered by intraperitoneal way and the animals were sacrificed in CO2 chamber 10 min after the administration of the radiotracer. Various organs were removed, weighted, their radioactivity was determined using an auto-gamma counter and the results were expressed as the percentage of the injected activity per gram of tissue (%ATI/g). In the control group only Na99mTcO4 was administered. The analysis of results shows that the highest uptakes 99mTc-AMA treated group were: ovary (7.11 +/- 1.43), spleen (3.54 +/- 1.05), thyroid (2.67 +/- 0.15), stomach (1.56 +/- 1.10), duodenum (0.87 +/- 0.52), muscular tissue (0.57 +/- 0.06), liver (0.52 +/- 0.25), and at control group: thyroid (16.45 +/- 2.57), ovary (1.28 +/- 0.12), liver (1.10 +/- 0.04), spleen (0.57 +/- 0.07) and muscular tissue (0.26 +/- 0.03). The results obtained suggest that 99mTc-AMA may be used to study the bioavailability of amantadine and evaluate its effect in sexual behavior in female rats. 相似文献
17.
Zilin Yu Giuseppe Carlucci Hildo J. K. Ananias Rudi A. J. O. Dierckx Shuang Liu Wijnand Helfrich Fan Wang Igle J. de Jong Philip H. Elsinga 《Amino acids》2013,44(2):543-553
Multimerization of peptides can improve the binding characteristics of the tracer by increasing local ligand concentration and decreasing dissociation kinetics. In this study, a new bombesin homodimer was developed based on an ε-aminocaproic acid-bombesin(7–14) (Aca-bombesin(7–14)) fragment, which has been studied for targeting the gastrin-releasing peptide receptor (GRPR) in prostate cancer. The bombesin homodimer was conjugated to 6-hydrazinopyridine-3-carboxylic acid (HYNIC) and labeled with 99mTc for SPECT imaging. The in vitro binding affinity to GRPR, cell uptake, internalization and efflux kinetics of the radiolabeled bombesin dimer were investigated in the GRPR-expressing human prostate cancer cell line PC-3. Biodistribution and the GRPR-targeting potential were evaluated in PC-3 tumor-bearing athymic nude mice. When compared with the bombesin monomer, the binding affinity of the bombesin dimer is about ten times lower. However, the 99mTc labeled bombesin dimer showed a three times higher cellular uptake at 4 h after incubation, but similar internalization and efflux characters in vitro. Tumor uptake and in vivo pharmacokinetics in PC-3 tumor-bearing mice were comparable. The tumor was visible on the dynamic images in the first hour and could be clearly distinguished from non-targeted tissues on the static images after 4 h. The GRPR-targeting ability of the 99mTc labeled bombesin dimer was proven in vitro and in vivo. This bombesin homodimer provides a good starting point for further studies on enhancing the tumor targeting activity of bombesin multimers. 相似文献
18.
Stable one-step technetium-99m labeling of His-tagged recombinant proteins with a novel Tc(I)-carbonyl complex. 总被引:3,自引:0,他引:3
R Waibel R Alberto J Willuda R Finnern R Schibli A Stichelberger A Egli U Abram J P Mach A Plückthun P A Schubiger 《Nature biotechnology》1999,17(9):897-901
We have developed a technetium labeling technology based on a new organometallic chemistry, which involves simple mixing of the novel reagent, a 99m Tc(I)-carbonyl compound, with a His-tagged recombinant protein. This method obviates the labeling of unpaired engineered cysteines, which frequently create problems in large-scale expression and storage of disulfide-containing proteins. In this study, we labeled antibody single-chain Fv fragments to high specific activities (90 mCi/mg), and the label was very stable to serum and all other challenges tested. The pharmacokinetic characteristics were indistinguishable from iodinated scFv fragments, and thus scFV fragments labeled by the new method will be suitable for biodistribution studies. This novel labeling method should be applicable not only to diagnostic imaging with 99mTc, but also to radioimmunotherapy approaches with 186/188 Re, and its use can be easily extended to almost any recombinant protein or synthetic peptide. 相似文献
19.
Marcelo Tatit Sapienza Fabio Luiz Navarro Marques Miriam Roseli Yoshie Okamoto Fausto Haruki Hironaka Carlos Alberto Buchpiguel 《Cellular and molecular biology, including cyto-enzymology》2002,48(5):511-516
Animal models are currently used to verify the biodistribution of different radiopharmaceuticals before its clinical application in Nuclear Medicine; however, there may be some limitations. The utilization of labelled anti-tumor monoclonal antibodies (MoAb) in experimental models often requires implant of human antigens (usually a cellular implant), which cannot be achieved in immunocompetent animals. Our purpose was to label an anti-CEA MoAb with technetium-99m (99Tc) and to validate a simplified animal model using a noncellular antigenic implant. MoAb was directly labelled with 99mTc, after reduction with 2-mercaptoethanol. Labeling efficiency was checked by ascending chromatography and immunoreactive fraction was measured in plastic wells sensitized with the antigen. Radiopharmaceutical biodistribution was evaluated by dissection and scintigraphy in 5 mice groups; following the subcutaneous administration of Al(OH)3, CEA adsorbed Al(OH)2 and a control group evaluation. Labeling efficiency was 94+/-3%, which showed to be stable for 24 hr, with immunoreactive fraction above 50%. Invasive biodistribution evaluation showed prolonged blood retention, hepatic and renal uptake. A significant increase in uptake was observed in scintigraphic studies of animals with CEA-adsorbed Al(OH)3 implants compared with the other groups (p<0.05). The non-cellular antigenic implant model simplifies the pre-clinical evaluation of labelled MoAb. 相似文献
20.
We have developed a radioisotopic microassay of cell-mediated immunity employing target cells prelabeled with technetium-99m (99mTc), a high specific activity metastable gamma emitter. Labeling kinetics, release and reutilization, subcellular localization, and effects of 99mTc on DNA and protein synthesis have been investigated. Target cells were optimally labeled with 10 mCi of 99mTc at 37 °C for 10 min. Cyclic freezing and thawing released less than 10% of total bound radioisotope. Spontaneous leakage of 99mTc by monolayer cells was negligible over 48 hr and that which was released appeared to be nonreutilizable. Cell fractionation revealed that nuclear, mitochondrial, and microsomal fractions all were labeled with 99mTc. The incorporation of 3H-thymidine and 3H-amino acids was not impaired in 99mTc-labeled cells.The alloimmune reactivity of C57BL/6 mice which had received A/J skin allografts was studied by means of the 99mTc microcytotoxicity assay. Cell-mediated immunity was clearly evident at 7 days postgrafting, peaked at 14 days, and had declined to background levels by 21 days. These findings correlated well with initial acceptance and ultimate rejection of the allografts. The rapid labeling time without dependence upon cell division for incorporation, high specific activity, low spontaneous release, and nonreutilizability are important advantages of 99mTc over other radionuclides which have been employed in in vitro assays of cell-mediated immunity. 相似文献