Comparison between two labeled agents in mice using a coinjection-ratio approach in contrast to a conventional group approach
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Authors
Dou, ShupingWang, Yuzhen
Barton, Bruce A.
Chen, Ling
Rusckowski, Mary
Shultz, Leonard D.
Greiner, Dale L.
Liu, Guozheng
UMass Chan Affiliations
Program in Molecular MedicineDepartment of Quantitative Health Sciences
Department of Radiology
Document Type
Journal ArticlePublication Date
2014-01-01Keywords
UMCCTS fundingStatistical analysis
in vivo evaluation
biodistribution
translational study
tumor pretargeting
Animal Experimentation and Research
Neoplasms
Other Analytical, Diagnostic and Therapeutic Techniques and Equipment
Radiology
Statistics and Probability
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INTRODUCTION: The differences between two agents often need to be accurately defined in vivo. Usually they are injected respectively into two groups of subjects. However, if the two agents do not interact with each other in vivo, a coinjection would serve the same purpose. We believe some individual differences in biodistribution may be circumvented through this approach by calculating organ level ratios. METHODS: A model system of MORF/cMORF pretargeting (MORF/cMORF is a complementary pair of DNA analogues) was employed in connection with an on-going tumor therapeutic project. Human LS174T cells were implanted into the flank of severely immuno-compromised NOD-scid IL2rg(null) mice. The tumor was confirmed to express TAG-72 antigens. At 16 days post tumor inoculation, mice received IV 60 mug of MORF-conjugated CC49 (an antiTAG-72 antibody), followed 2 days later by a low-mass-dose IV coinjection containing 2.5 mug of (90)Y-cMORF and 2.5 mug of (99m)Tc-cMORF. At 3 h post radioactivity injection, the distribution of (99m)Tc was imaged on a SPECT/CT camera and then organs were excised and counted for (90)Y and (99m)Tc. Because the two labeled cMORFs do not react or interact with each other in vivo, the two groups of (90)Y and (99m)Tc data enabled a conventional group comparison. In a new effort, (90)Y/(99m)Tc ratios were calculated. Student's t-test and retrospective power analysis were performed for both approaches. In the new approach, the ratios were set at 1 as the null hypothesis. RESULTS: The Student's t-test in the conventional group approach indicated that the two labeled cMORFs distributed similarly, but significant differences were observed in salivary gland and large intestines. The coinjection-ratio approach certainly did not subvert the results of the conventional approach but revealed subtler differences. The P values were reduced, the powers were increased in most organs, and more significant differences were observed. The increased sensitivity was due to the reduced CV%s (SD/average*100%) of the (90)Y/(99m)Tc ratios. Therefore, some individual differences were circumvented and notably the ratio approach differentiated individual differences into ratio-correctable and ratio-uncorrectable. CONCLUSIONS: Although the conventional approach is reliable, the coinjection-ratio approach using organ level ratios is more sensitive and therefore is recommended whenever possible. In addition, it differentiates individual differences into "coinjection correctable" and "coinjection uncorrectable".Source
Dou S, Wang Y, Barton B, Chen L, Rusckowski M, Shultz LD, Greiner DL, Liu G. Comparison between two labeled agents in mice using a coinjection-ratio approach in contrast to a conventional group approach. Nucl Med Biol. 2014 Jan;41(1):127-31. doi: 10.1016/j.nucmedbio.2013.10.001. Link to article on publisher's site
DOI
10.1016/j.nucmedbio.2013.10.001Permanent Link to this Item
http://hdl.handle.net/20.500.14038/30111PubMed ID
24210286Related Resources
ae974a485f413a2113503eed53cd6c53
10.1016/j.nucmedbio.2013.10.001