scholarly journals Novel Biological and Molecular Characterization in Radiopharmaceutical Preclinical Design

2021 ◽  
Vol 10 (21) ◽  
pp. 4850
Author(s):  
Nicoletta Urbano ◽  
Manuel Scimeca ◽  
Anna Tolomeo ◽  
Vincenzo Dimiccoli ◽  
Elena Bonanno ◽  
...  
Keyword(s):  
Small Animal ◽  
Super Resolution ◽  
Optical Microscope ◽  
Cellular Level ◽  
Post Injection ◽  
Digital Autoradiography ◽  
Time Points ◽  
Biodistribution Studies ◽  
Psma Inhibitor ◽  
Screen Surface

In this study, the potential of a digital autoradiography system equipped with a super resolution screen has been evaluated to investigate the biodistribution of a 18F-PSMA inhibitor in a prostate cancer mouse model. Twelve double xenograft NOD/SCID mice (LNCAP and PC3 tumours) were divided into three groups according to post-injection time points of an 18F-PSMA inhibitor. Groups of 4 mice were used to evaluate the biodistribution of the radiopharmaceutical after 30-, 60- and 120-min post-injection. Data here reported demonstrated that the digital autoradiography system is suitable to analyse the biodistribution of an 18F-PSMA inhibitor in both whole small-animal bodies and in single organs. The exposure of both whole mouse bodies and organs on the super resolution screen surface allowed the radioactivity of the PSMA inhibitor distributed in the tissues to be detected and quantified. Data obtained by using a digital autoradiography system were in line with the values detected by the activity calibrator. In addition, the image obtained from the super resolution screen allowed a perfect overlap with the tumour images achieved under the optical microscope. In conclusion, biodistribution studies performed by the autoradiography system allow the microscopical modifications induced by therapeutic radiopharmaceuticals to be studied by comparing the molecular imaging and histopathological data at the sub-cellular level.

Radiopharmaceutical preclinical investigation: an accurate and multidisciplinary approach

2021 ◽  
Vol 14 ◽  
Author(s):  
Nicoletta Urbano ◽  
Manuel Scimeca ◽  
Elena Bonanno ◽  
Orazio Schillaci
Keyword(s):  
Prostate Cancer ◽  
Laser Scanning ◽  
Molecular Mechanisms ◽  
Super Resolution ◽  
Immunohistochemical Analysis ◽  
Proliferation Index ◽  
Choline Uptake ◽  
Digital Autoradiography ◽  
Biodistribution Studies ◽  
Clinical Investigations

Background: The development of less expensive and pivotal methodologies, capable to support the researchers in the radiopharmaceutical pre-clinical investigations could provide a crucial incentive for developing biomedical research involved in the realization of tailored target therapies. Objective: The aim of this pilot study was to evaluate the capability of a digital autoradiography system equipped with a laser scanning device to perform [18F]choline biodistribution evaluation in a xenograft mouse model of prostate cancer. Methods: PC3 prostate cancer cells were used to develop xenografts in NOD/SCID mice. The biodistribution of the radiopharmaceutical was evaluated at 30,60 and 120 min after injection in excised organs by using a digital autoradiography system equipped with super resolution laser screen. Histological and immunohistochemical analysis were performed to correlate the [18F]choline uptake with morphological and molecular tumours characteristics. Results: Data here reported clearly indicate the possibility to perform accurate biodistribution studies by using the digital autoradiographic system equipped with a super resolution screen. Specifically, a significant increase in the [18F]choline inhibitor uptake in PC3 tumours as compared to heart, bowel, liver and kidney at both 30 and 60 min was observed. More important, the digital autoradiographic system showed signal uptake almost exclusively in the PC3 tumors at 60 min post-injection. Noteworthy, immunohistochemical analysis demonstrated a strong overlapping between the [18F]choline uptake and the proliferation index (Ki67 expression). Conclusions: The use of autoradiography system in pre-clinical investigations could shed new light on the molecular mechanisms that orchestrate the tissues damage induced by therapeutical radiopharmaceuticals.

Synthesis, characterization, and bioevaluation of 99mTc nitrido-oxiracetam as a brain imaging model

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
M. H. Sanad ◽  
S. F. A. Rizvi ◽  
A. B. Farag
Keyword(s):  
Reaction Time ◽  
Brain Imaging ◽  
Radiochemical Purity ◽  
Post Injection ◽  
Effective Factors ◽  
Imaging Model ◽  
Biodistribution Studies

Abstract In this work, the radiotracer [99mTc]nitrido-oxiracetam complex was labeled in the presence of 99mTc-nitrido as a core. In order to get the highest radiochemical purity, many effective factors have been studied such as temperature of the reaction, time of the reaction, the pH of the reaction mixture, substrate amount, and stability to give high percent more than 99%. Finally, biodistribution studies have been indicated the convenience of [99mTc]nitrido-oxiracetam as a new radiotracer that could be used in brain imaging. Giving a maximum uptake of 10.6% at 30 min post injection.

scholarly journals Proof-of-Concept Study of the NOTI Chelating Platform: Preclinical Evaluation of 64Cu-Labeled Mono- and Trimeric c(RGDfK) Conjugates

2020 ◽  
Vol 23 (1) ◽  
pp. 95-108
Author(s):  
Sebastian Martin ◽  
Stephan Maus ◽  
Tobias Stemler ◽  
Florian Rosar ◽  
Fadi Khreish ◽  
...  
Keyword(s):  
Ambient Temperature ◽  
Building Block ◽  
Metal Binding ◽  
Small Animal ◽  
Building Blocks ◽  
Small Animal Pet ◽  
Proof Of Concept ◽  
Binding Properties ◽  
Concept Study ◽  
Biodistribution Studies

Abstract Purpose We recently developed a chelating platform based on the macrocycle 1,4,7-triazacyclononane with up to three five-membered azaheterocyclic arms for the preparation of 68Ga- and 64Cu-based radiopharmaceuticals. Based on this platform, the chelator scaffold NOTI-TVA with three additional carboxylic acid groups for bioconjugation was synthesized and characterized. The primary aims of this proof-of-concept study were (1) to evaluate if trimeric radiotracers on the basis of the NOTI-TVA 6 scaffold can be developed, (2) to determine if the additional substituents for bioconjugation at the non-coordinating NH atoms of the imidazole residues of the building block NOTI influence the metal binding properties, and (3) what influence multiple targeting vectors have on the biological performance of the radiotracer. The cyclic RGDfK peptide that specifically binds to the αvß3 integrin receptor was selected as the biological model system. Procedures Two different synthetic routes for the preparation of NOTI-TVA 6 were explored. Three c(RGDfK) peptide residues were conjugated to the NOTI-TVA 6 building block by standard peptide chemistry providing the trimeric bioconjugate NOTI-TVA-c(RGDfK)39. Labeling of 9 with [64Cu]CuCl2 was performed manually at pH 8.2 at ambient temperature. Binding affinities of Cu-8, the Cu2+ complex of the previously described monomer NODIA-Me-c(RGDfK) 8, and the trimer Cu-9 to integrin αvß3 were determined in competitive cell binding experiments in the U-87MG cell line. The pharmacokinetics of both 64Cu-labeled conjugates [64Cu]Cu-8 and [64Cu]Cu-9 were determined by small-animal PET imaging and ex vivo biodistribution studies in mice bearing U-87MG xenografts. Results Depending on the synthetic route, NOTI-TVA 6 was obtained with an overall yield up to 58 %. The bioconjugate 9 was prepared in 41 % yield. Both conjugates [64Cu]Cu-8 and [64Cu]Cu-9 were radiolabeled quantitatively at ambient temperature in high molar activities of Am ~ 20 MBq nmol−1 in less than 5 min. Competitive inhibitory constants IC50 of c(RDGfK) 7, Cu-8, and Cu-9 were determined to be 159.5 ± 1.3 nM, 256.1 ± 2.1 nM, and 99.5 ± 1.1 nM, respectively. In small-animal experiments, both radiotracers specifically delineated αvß3 integrin-positive U-87MG tumors with low uptake in non-target organs and rapid blood clearance. The trimer [64Cu]Cu-9 showed a ~ 2.5-fold higher tumor uptake compared with the monomer [64Cu]Cu-8. Conclusions Functionalization of NOTI at the non-coordinating NH atoms of the imidazole residues for bioconjugation was straightforward and allowed the preparation of a homotrimeric RGD conjugate. After optimization of the synthesis, required building blocks to make NOTI-TVA 6 are now available on multi-gram scale. Modifications at the imidazole groups had no measurable impact on metal binding properties in vitro and in vivo suggesting that the NOTI scaffold is a promising candidate for the development of 64Cu-labeled multimeric/multifunctional radiotracers.

scholarly journals New 55Co-labeled Albumin-Binding Folate Derivatives as Potential PET Agents for Folate Receptor Imaging

2019 ◽  
Vol 12 (4) ◽  
pp. 166 ◽  
Author(s):  
Lauren L. Radford ◽  
Solana Fernandez ◽  
Rebecca Beacham ◽  
Retta El Sayed ◽  
Renata Farkas ◽  
...  
Keyword(s):  
Folate Receptor ◽  
Small Animal ◽  
Small Animal Pet ◽  
Receptor Imaging ◽  
Albumin Binding ◽  
Liver Uptake ◽  
Biodistribution Studies ◽  
Positron Emission

Overexpression of folate receptors (FRs) on different tumor types (e.g., ovarian, lung) make FRs attractive in vivo targets for directed diagnostic/therapeutic agents. Currently, no diagnostic agent suitable for positron emission tomography (PET) has been adopted for clinical FR imaging. In this work, two 55Co-labeled albumin-binding folate derivatives-[55Co]Co-cm10 and [55Co]Co-rf42-with characteristics suitable for PET imaging have been developed and evaluated. High radiochemical yields (≥95%) and in vitro stabilities (≥93%) were achieved for both compounds, and cell assays demonstrated FR-mediated uptake. Both 55Co-labeled folate conjugates demonstrated high tumor uptake of 17% injected activity per gram of tissue (IA/g) at 4 h in biodistribution studies performed in KB tumor-bearing mice. Renal uptake was similar to other albumin-binding folate derivatives, and liver uptake was lower than that of previously reported [64Cu]Cu-rf42. Small animal PET/CT images confirmed the biodistribution results and showed the clear delineation of FR-expressing tumors.

scholarly journals Optical nanoscopy

2020 ◽  
Vol 43 (8) ◽  
pp. 385-455
Author(s):  
A. Diaspro ◽  
P. Bianchini
Keyword(s):  
Artificial Intelligence ◽  
Spatial Resolution ◽  
Scanning Probe Microscopy ◽  
Molecular Level ◽  
Super Resolution ◽  
Optical Microscope ◽  
Scanning Probe ◽  
Living Systems ◽  
Starting Point ◽  
Basic Concepts

Abstract This article deals with the developments of optical microscopy towards nanoscopy. Basic concepts of the methods implemented to obtain spatial super-resolution are described, along with concepts related to the study of biological systems at the molecular level. Fluorescence as a mechanism of contrast and spatial resolution will be the starting point to developing a multi-messenger optical microscope tunable down to the nanoscale in living systems. Moreover, the integration of optical nanoscopy with scanning probe microscopy and the charming possibility of using artificial intelligence approaches will be shortly outlined.

scholarly journals Toxicity at the cellular level of artificial synthetic flavorings

2016 ◽  
Vol 38 (3) ◽  
pp. 297
Author(s):  
Ila Monize Sousa Sales ◽  
Jussara Damascena de Oliveira ◽  
Fabelina Karollyne Silva dos Santos ◽  
Lidiane De Lima Feitoza ◽  
João Marcelo de Castro e Sousa ◽  
...  
Keyword(s):  
Cell Division ◽  
Root Meristem ◽  
Combined Treatment ◽  
Optical Microscope ◽  
Cellular Level ◽  
Combined Treatments ◽  
Division Rate ◽  
Cell Division Rate ◽  
Allium Cepa L ◽  
Genotoxic Action

 The goal of the present study was to evaluate the cytotoxicity and genotoxicity of artificial synthetic flavoring agents cookie and tutti-frutti. To this end, root meristem cells of Allium cepa L. were exposed to these substances in exposure times of 24 and 48 hour using individual doses of 0.3; 0.6 and 0.9 mL and doses combined as follows: 0.3 mL + 0.3 mL; 0.6 mL and 0.9 mL + 0.6 mL + 0.9 mL. After applying the treatments, root meristems were fixed, hydrolyzed, stained and analyzed a total of 5,000 cells using an optical microscope to evaluate each dose and combined treatment. All three doses of cookie flavoring and combined treatments significantly inhibited cell division of the tissue studied. Doses of tutti-frutti caused no change in cell division rate. In addition, doses of both flavorings and treatments combining these solutions induced cell aberrations in a significant number of cells to the A. cepa system. Therefore, under these analytical conditions, cookie flavoring and combined doses were cytotoxic and genotoxic, and tutti-frutti flavoring, although non-cytotoxic, demonstrated genotoxic action. 

Super-resolution optical microscope: principle, instrumentation, and application

2019 ◽  
Vol 20 (5) ◽  
pp. 608-630
Author(s):  
Bao-kai Wang ◽  
Martina Barbiero ◽  
Qi-ming Zhang ◽  
Min Gu
Keyword(s):  
Super Resolution ◽  
Optical Microscope

Targeted tumor MRI with gadobutrol-loaded anti-HER2 immunoliposomes

2016 ◽  
Vol 58 (5) ◽  
pp. 573-580 ◽  
Author(s):  
Weicui Chen ◽  
Bo Liu ◽  
Jun Chen ◽  
Guoqing Liu ◽  
Xian Liu
Keyword(s):  
Contrast Agent ◽  
Contrast Agents ◽  
Signal To Noise Ratio ◽  
Cellular Level ◽  
Cancer Tissue ◽  
Post Injection ◽  
Specific Tumor ◽  
Noise Ratio ◽  
Targeted Contrast Agent

Background Immunoliposomes have been used to deliver MR contrast agents to cancer tissue by targeting tumor associated antigens, thus enabling the visualization of biological processes at the cellular level. Purpose To develop and evaluate the feasibility of specific HER2 targeted liposomal MR contrast agent. Material and Methods Gd-loaded anti-HER2 immunolipomes (Gd-ILs) and non-targeted PEGylated liposomes (Gd-NTLs) were prepared and characterized. Tumor bearing animals were randomized into three groups: Gd- ILs, Gd- NTLs and gadobutrol. Animals were imaged prior and 5, 15, 60, 120 and 180 min after i.v. injection of different contrast agents. The signal intensity enhancement percentage, signal- to- noise ratio and contrast- to –noise ratio was used to qualify tumor enhancement of different groups. After imaging, tumors were excised for histological examination. Results In vivo dynamic MR images, the specific targeted contrast agent bound to tumor tissue and result in a gradual and persisting enhancement for at least 3 hours in mice bearing tumor xenografts, reaching a maximum of 87.7% enhancement after 120 min post-injection. Gd-ILs demonstrated superior tumor enhancement over control non target contrast agent and gadobutrol in HER2 overexpressing tumors at 60, 120 and 180 min post- injection. The SNR and CNR of Gd-ILs in the tumors were significantly greater than that of Gd-NTLs at 60, 120, 180 min post- injection. Conclusion The results indicate the feasibility of Gd-ILs providing prolonged circulation, specific tumor enhancement and cancer cell recognition as targeted contrast agent.

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