Background: Radiobioconjugate targeting using monoclonal antibodies linked to a high-energy radionuclide is a promising approach for treating metastatic cancer. The central problem of ...radiobioconjugate targeting is the small fraction of radiobioconjugate localized in the tumor. Pretargeting based on avidin–biotin approach has been recommended to maximize tumor targeting. The current study was conceded with an aim to assess a selective targeting strategy for the site-specific deliverance of an injected radioactive dose to the tumor cells. Methods: Two labeling protocols were tested and evaluated, both for the direct and indirect radiolabeling of antibodies with radionuclide technetium. A comparative evaluation of biodistribution studies relating to the deposition of injected dose in different organs was carried out in tumor-bearing nude mice both for a direct single-step and indirect multistep pretargeting approach. Results: High concentration of the injected dose was accounted in the nontarget organs and blood for a direct targeting mode, as compared to indirect multistep pretargeting with high tumor uptake. Better tumor visibility and high tumor/nontumor ratio were observed at 24 h and 48 h. However, a considerable deposition of radioactivity in the organs such as liver, spleen, kidney, and lungs as a nonspecific, reticuloendothelial system uptake was observed as a cause of concern and the use of certain blocking agents were explored, effective for reducing the same. Conclusions: The study demonstrates a successful targeting efficiency of the radiolabeled bioconjugate for technetium (Tc-99m), through a multistep pretargeting approach, and the same can be applied for other related therapy radionuclides also.
Radiobioconjugate therapy, recommended as one of the effective modalities for the treatment of cancer cells, is based on the concept of delivering the localized radiation at the cellular level to the ...disease site using a biological moiety. The high tumor/nontumor ratio is the essentially a sine qua non for the successful execution of targeted therapy which is highly desired. The central problem associated to radiobioconjugate therapy is the small fraction of a radiobioconjugate localized to the tumor, while the major fraction of it is delivered to the nontarget organs (reticuloendothelial system deposition). The current article focuses on the better perceptive of the factors of understanding, which includes the selection and expansion of sophisticated molecular carriers, assortment of a suitable radionuclide based on the class of emission, linear energy transmit, and the material radiophysical half-life. In addition, a concern to the biochemical interactions taking place at the molecular level, selection of a specific targeting strategy for designing effective treatment regimes, and importantly the challenges associated to it have also been discussed.
Cardiovascular Magnetic Resonance is increasingly used to differentiate the aetiology of cardiomyopathies. Late Gadolinium Enhancement (LGE) is the reference standard for non-invasive imaging of ...myocardial scar and focal fibrosis and is valuable in the differential diagnosis of ischaemic versus non-ischaemic cardiomyopathy. Diffuse fibrosis may go undetected on LGE imaging. Tissue characterisation with parametric mapping methods has the potential to detect and quantify both focal and diffuse alterations in myocardial structure not assessable by LGE. Native and post-contrast T1 mapping in particular has shown promise as a novel biomarker to support diagnostic, therapeutic and prognostic decision making in ischaemic and non-ischaemic cardiomyopathies as well as in patients with acute chest pain syndromes. Furthermore, changes in the myocardium over time may be assessed longitudinally with this non-invasive tissue characterisation method.
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