A rapid method for the determination of human CEA/mouse anti-CEA immune complexes in patients undergoing immunoscintigraphy

We report here on a new and quick procedure to isolate human (hu) CEA mouse anti CEA immune complexes of sera from patients admitted for immunoscintigraphy with radiolabeled monoclonal anti CEA antibody. This method employs rabbit anti mouse IgG immune affinity chromatography together with a commercial CEA-IRMA kit for the specific isolation of immune complexes. By applying this procedure we were able to show that immune complex formation increased in parallel to CEA serum concentration. The formation of immune complexes did not significantly affect tumor detection by immunoscintigraphy.Abbreviations CEA Carcinoembryonic antigen - DTE Dithioerythritol - EDTE Ethylenediaminetetraacetate - PMSF phenylmethylsulfonyl flouride - IRMA immunoradiometric assay - p.i. post injectionem Deceased     

A passive haemagglutination test for human anti-mouse antibody (HAMA) responses in patients undergoing immunoscintigraphy

Sera from seven patients with ovarian or colorectal carcinoma who had been given only single injections of 131I or 111In labelled IgG1, IgG2a or IgG2b monoclonal antibodies for immunoscintigraphy 2 weeks to 9 months earlier were tested for their ability to agglutinate sheep red blood cells coated with a mouse monoclonal antibody. Six showed agglutination, and this was still seen when sera were diluted to 1/125 in four patients and as low as 1/3125 in the other two. Sera from rats and mice which had been injected with monoclonal antibody also caused agglutination, which in the case of the mouse sera is due to the presence of anti-idiotypic antibody. This study shows that it is feasible to detect HAMA by a rapid, simple, passive haemagglutination reaction.     

Diverse characteristics of111In labelled anti-CEA monoclonal antibodies for tumour immunoscintigraphy: Radiolabelling,biodistribution and imaging studies in mice with human tumour xenografts

Three monoclonal anti-CEA antibodies, designated 161, 198 (both IgG1) and 228 (IgG2a) have been labelled with¹¹¹In via DTPA chelation and assessed for localization in human gastro-intestinal carcinomas as xenografts in athymic nude mice. Following reaction of the antibodies with DTPA anhydride, efficiency of chelation of¹¹¹In varied between the antibodies with mean values of 30%, 52% and 62% with 161, 198 and 228 respectively. Gel filtration chromatography with all three labelled antibodies showed radiolabel predominantly coincident with IgG with little radioactivity in either high molecular weight form or as free¹¹¹In. However, the efficiency of binding of radiolabelled antibodies to CEA producing tumour cells varied, with maxima of 42%, 65% and 20% for 161, 198 and 228. In vivo, in mice,¹¹¹In was excreted at virtually identical rates (half times approx. 12 days) with all three prepartions and this was similar to the clearance of indium injected as¹¹¹In-indium chloride, but¹¹¹In-DTPA was rapidly eliminated (half time approximately 5 h). After injection inton mice with CEA producing xenografts of colon carcinoma HT29 and LS174T and gastric carcinoma MKN 45, circulating radiolabel was still predominantly in the form of labelled antibody with little or no detectable immune complexes or¹¹¹In labelled transferrin. Tumour localization of all three antibodies was visualized by gamma camera imaging with target: non target ratios of up to 5:1. Dissection of mice with MKN45 gastric carcinoma xenograft showed 16%, 19.5% and 13% of the injected dose of¹¹¹In from 161, 198 and 228 antibodies in each g of tumour tissue. Tumour to liver ratios were 3.8:1, 3.4:1 and 3.3:1. Similar studies in mice with xenografts of a human osteosarcoma, virtually devoid of CEA, showed no tumour localization with any of the antibodies (tumour: liver ratios <0.8:1).These studies illustrate the diverse nature of anti-CEA antibodies as bases for radiopharmaceutical preparations, and emphasise that in vitro criteria alone may not reflect in vivo tumour localization capacity.     

Diverse characteristics of 111In labelled anti-CEA monoclonal antibodies for tumour immunoscintigraphy: radiolabelling, biodistribution and imaging studies in mice with human tumour xenografts

Three monoclonal anti-CEA antibodies, designated 161, 198 (both IgG1) and 228 (IgG2a) have been labelled with 111In via DTPA chelation and assessed for localization in human gastro-intestinal carcinomas as xenografts in athymic nude mice. Following reaction of the antibodies with DTPA anhydride, efficiency of chelation of 111In varied between the antibodies with mean values of 30%, 52% and 62% with 161, 198 and 228 respectively. Gel filtration chromatography with all three labelled antibodies showed radiolabel predominantly coincident with IgG with little radioactivity in either high molecular weight form or as free 111In. However, the efficiency of binding of radiolabelled antibodies to CEA producing tumour cells varied, with maxima of 42%, 65% and 20% for 161, 198 and 228. In vivo, in mice, 111In was excreted at virtually identical rates (half times approx. 12 days) with all three preparations and this was similar to the clearance of indium injected as 111In-indium chloride, but 111In-DTPA was rapidly eliminated (half time approximately 5 h). After injection into mice with CEA producing xenografts of colon carcinoma HT29 and LS174T and gastric carcinoma MKN 45, circulating radiolabel was still predominantly in the form of labelled antibody with little or no detectable immune complexes or 111In labelled transferrin. Tumour localization of all three antibodies was visualized by gamma camera imaging with target: non target ratios of up to 5:1. Dissection of mice with MKN45 gastric carcinoma xenograft showed 16%, 19.5% and 13% of the injected dose of 111In from 161, 198 and 228 antibodies in each g of tumour tissue.(ABSTRACT TRUNCATED AT 250 WORDS)     

A method for rapid determination of the energy of electron beams from medical linear accelerators

A method has been developed using a Varian Clinac-18 LINAC for the rapid determination of electron beam energy for clinically used linear accelerators. The method involves measuring the ionization values in a water or polystyrene phantom with an ion chamber at two predetermined depths. Then with predetermined Bremsstrahlung "tail" values which are presented here or which can be developed by the user, the practical range, Rp can be measured. With the Rp, the effective surface energy Eo of the electron beam can be determined by the Markus range-energy formula. Thus, by measuring just two depth ionization values, one is quickly able to determine the Eo of an electron beam without plotting a full depth ionization curve.     

A fundamental study of immunoscintigraphy with 131I-labeled anti-CA 19-9 and anti-CEA monoclonal antibodies--imaging of tumor-bearing mice by IMACIS-1 and cell ELISA with human tumor cells

A study was made on 2 types of 131I-labeled anti-CA 19-9 and anti-CEA mouse monoclonal antibodies (IMACIS-1) against human cancer related antigen as to their usefulness in radioimmunoimaging. Tumor-bearing nude mice were used for comparison. The transplanted tumors (SW948, COLO 201) were clearly visualized 48-72 hours after administration of IMACIS-1. Tumor/blood ratio 72 hours after administration: 8.69 in COLO 201 and 5.70 in SW948, showing ca. 10-15 times as high as those in PC-3 and HEp-2. IMACIS-1 therefore is considered useful in radioimmunoimaging of cancer. Analysis was made by in vitro cell ELISA. As a result, both of the cells specifically reacted with anti-CA 19-9 but not anti-CEA.     

Simple and rapid determination of myristicin in human serum

Myristicin (5-allyl-1-methoxy-2,3-methylenodioxybenzene) is the main component of nutmeg (Myristica fragrans Houtt.) essential oil. The increasing use of myristicin as a cheap hallucinogenic intoxicant, frequently causing fatal cases of myristicin poisoning, requires new methods for determination of this compound in blood. This report describes the rapid, simple, and useful procedure for myristicin analysis in human serum, involving myristicin–protein complex degradation before chromatographic analysis. The developed method is characterized by a high recovery (above 99 %), a low detection limit (6.0 ng/g) and good repeatability (average RDS of 2.01 %).     

Anti-carcinoembryonic antigen immunoscintigraphy (technetium-99m-monoclonal antibody BW 431/26) and serum CEA levels in patients with suspected primary and recurrent colorectal carcinoma

This study comprises a total of 141 patients with suspected primary and recurrent colorectal carcinomas, in whom immunoscintigraphy with 99mTc-Mab BW 431/26 was performed. Whole-body scans were done 5.5 hr and SPECT imaging of the abdominal region was done at 6 and 24 hr postinjection of 1100 MBq 99mTc-labeled Mab (1 mg). In the course of primary tumor identification (n = 65), sensitivity of anti-CEA immunoscintigraphy was 95%, specificity 91%. In the diagnosis of early recurrences (n = 76), immunoscintigraphy was the method of choice to clarify the problem (sensitivity 94%; specificity 86%). Overall sensitivity of immunoscintigraphy in patients with suspected colorectal carcinomas and early recurrences was 95%, specificity 88%. Human anti-mouse antibodies were found in 29% (80% predominantly anti-isotypic, 20% predominantly anti-idiotypic). In contrast to anti-CEA immunoscintigraphy, the results of serum CEA levels were rather disappointing. Only 18 out of the 43 surgically verified primary colorectal carcinomas and 17 out of 32 patients with recurrences showed elevated serum CEA levels. In our clinical experience with this 99mTc-labeled anti-CEA antibody, immunoscintigraphy can play an important role in the identification of early colorectal recurrences and in postoperative colorectal cancer patients it should be performed in cases with unclear transmission computed tomography.     

Bone marrow immunoscintigraphy for the detection of skeletal metastases in patients with breast cancer

In this study, we evaluated the efficacy of bone marrow immunoscintigraphy (BMIS) for the detection of skeletal metastases in 23 patients with histologically confirmed breast cancer. All patients underwent whole-body BMIS 3-6 h after the intravenous injection of 0.20-0.33 mg of the intact anti-NCA 95 MAb BW 250/183 labelled with 259-555 MBq 99Tcm and a whole-body 99Tcm-MDP bone scan. In four patients, BMIS SPET of the lumbar spine was also performed. Serum alkaline phosphatase was determined in all patients and the level of human anti-mouse antibody (HAMA) in 16. Final diagnosis was confirmed by radiology and 2 years follow-up. Compared with the 99Tcm-MDP bone scan, BMIS demonstrated better specificity (88% vs 75%) and a better positive predictive value (92% vs 85%). There were no significant differences between BMIS and the bone scan in the detection of skeletal metastases (P > 0.05). In one patient with normal planar BMIS of the lumbar spine, SPET disclosed a metastatic lesion in the bone marrow. The correlation coefficient between BMIS and bone scan and between BMIS and serum alkaline phosphatase was r = 0.688 and r = 0.483 respectively. One patient developed a minor HAMA response after BMIS. Patients with diffuse increased activity of the skull on the bone scan had a significantly higher skull to whole body ratio on BMIS (P < 0.01). Thus BMIS can improve the specificity and positive predictive value of bone scanning in the detection of skeletal metastases, with a low HAMA response. Diffuse increased activity of the skull on bone scans could be explained by bone marrow extension. SPET scanning of the spine may improve the sensitivity of BMIS.     

用灯盏乙素定量人血浆中异灯盏乙素的LC/MS/MS方法探讨

目的探讨用灯盏乙素定量人血浆中异灯盏乙素的LC/MS/MS方法。方法用AgiLent SB-C18柱(4.6 mm×150 mm,5μm),流动相为甲醇∶水∶甲酸(55∶43∶2)。采用电喷雾离子源(ESI),以选择反应监测(SRM)方式对灯盏乙素和异灯盏乙素及其苷元进行一级和二级质谱分析,离子反应分别为m/z 463→287和m/z 287→123。结果根据所得色谱和质谱数据,推断灯盏乙素可能的代谢产物和异灯盏乙素的结构,并测定人血浆中异灯盏乙素的浓度。结论用灯盏乙素定量异灯盏乙素的方法是可行的。     

A table for the rapid determination of RET and TDF values.

A table has been devised to allow rapid determination of the RET and TDF values for five-day a week therapy schemes which might be included in realistic treatment planning. 2. The table allows easy comparison of the RET and TDF values for different fractionation schemes or, conversely, the devising of equivalent fractionations for similar RET and TDF values. 3. Utilizing the decay tables of Orton and Ellis, it is possible to utilize the table for determining rapidly the total TDF for interrupted or split course treatment regimens. 4. In those departments which treat four days, rather than five days, per week, a table devised on the four-day treatment schedule could easily be devised.     

A rapid improved method for gamma-spectrometric determination of 202Tl impurities in [201Tl]-labelled radiopharmaceuticals.

Despite the cyclotron production method and the efficiency of the radiochemical procedures adopted, the long-lived radio-isotopic impurity 202Tl is always present in [201Tl]-labelled radio-pharmaceuticals, together with other short-lived impurities like, 200Tl. Rapid determination of the 202Tl impurity, can be achieved using HPGe gamma spectrometry and a detector shielded by a 5 mm thick envelope of lead. In this way, dead-time correction errors, Compton and X-ray background, are very efficiently avoided and suppressed. The same method could be applied routinely in nuclear medicine, to determine the radioisotopic purity of 201Tl by means of an ionisation chamber dose calibrator.