Authors: J A Scott

Topics: Acupuncture Points; Attitude of Health Personnel; Cultural Characteristics; Electric Conductivity; Medicine, Ayurvedic; Medicine, East Asian Traditional; Peer Review; Technetium

PubMed: 1740712
DOI: No ID Found

Review

Authors: Roger Alberto, Henrik Braband, Qaisar Nadeem...

Due to its long half-life of 2.111×10 y, technetium, Tc, offers the excellent opportunity of combining fundamental and ' classical ' organometallic or coordination chemistry with all methodologies of radiochemistry. Technetium chemistry is inspired by the applications of its short-lived metastable isomer Tc in molecular imaging and radiopharmacy. We present in this article examples about these contexts and the impact of purely basic oriented research on practical applications. This review shows how the chemistry of this element in the middle of the periodic system inspires the chemistry of neighboring elements such as rhenium. Reasons are given for the frequent observation that the chemistries of Tc and Tc are often not identical, compounds accessible for Tc, under certain conditions, are not accessible for Tc. The article emphasizes the importance of macroscopic technetium chemistry not only for research but also for advanced education in the general fields of radiochemistry.

Topics: Molecular Imaging; Radiochemistry; Radiopharmaceuticals; Rhenium; Technetium

PubMed: 33357288
DOI: 10.2533/chimia.2020.953

Review

Authors: Oxana V Kharissova, Miguel A Méndez-Rojas, Boris I Kharisov...

Recent advances (during the 2007-2014 period) in the coordination and organometallic chemistry of compounds containing natural and artificially prepared radionuclides (actinides and technetium), are reviewed. Radioactive isotopes of naturally stable elements are not included for discussion in this work. Actinide and technetium complexes with O-, N-, N,O, N,S-, P-containing ligands, as well π-organometallics are discussed from the view point of their synthesis, properties, and main applications. On the basis of their properties, several mono-, bi-, tri-, tetra- or polydentate ligands have been designed for specific recognition of some particular radionuclides, and can be used in the processes of nuclear waste remediation, i.e., recycling of nuclear fuel and the separation of actinides and fission products from waste solutions or for analytical determination of actinides in solutions; actinide metal complexes are also usefulas catalysts forcoupling gaseous carbon monoxide,as well as antimicrobial and anti-fungi agents due to their biological activity. Radioactive labeling based on the short-lived metastable nuclide technetium-99m ((99m)Tc) for biomedical use as heart, lung, kidney, bone, brain, liver or cancer imaging agents is also discussed. Finally, the promising applications of technetium labeling of nanomaterials, with potential applications as drug transport and delivery vehicles, radiotherapeutic agents or radiotracers for monitoring metabolic pathways, are also described.

Topics: Actinoid Series Elements; Coordination Complexes; Elements, Radioactive; Ligands; Organometallic Compounds; Technetium

PubMed: 25061724
DOI: 10.3390/molecules190810755

Authors: Seyedeh Masoumeh Ghoreishi, Ali Khalaj, Omid Sabzevari...

INTRODUCTION

Nowadays, molecular imaging radiopharmaceuticals', nanoparticles', and/or small-molecule biomarkers' applications are increasing rapidly worldwide. Thus, researchers focus on providing the novel, safe, and cost-effective ones.

MATERIALS AND METHODS

In the present experiment, technetium-99m (Tc)-labeled PEG-citrate dendrimer-G conjugated with glutamine (nanoconjugate) was designed and assessed as a novel tumor imaging probe both in vitro and in vivo. Nanoconjugate was synthesized and the synthesis was confirmed by Fourier transform infrared, proton nuclear magnetic resonance, liquid chromatography-mass spectrometry, dynamic light scattering, and static light scattering techniques. The toxicity was assessed by XTT and apoptosis and necrosis methods.

RESULTS

Radiochemical purity indicates that the anionic dendrimer has a very high potential to complex formation with Tc and is also very stable in the human serum in different times. Results from the imaging procedures showed potential ability of nanoconjugates to detect tumor site.

CONCLUSION

Suitable features of the anionic dendrimer show that it is a promising agent to improve nanoradiopharmaceuticals.

Topics: Animals; Dendrimers; Glutamine; Humans; In Vitro Techniques; Lung Neoplasms; Mice; Molecular Imaging; Nanoparticles; Radiopharmaceuticals; Technetium; Tissue Distribution; Tumor Cells, Cultured

PubMed: 30154653
DOI: 10.2147/IJN.S157426

Review

Authors: Christiane A Kluba, Thomas L Mindt

The Click-to-Chelate approach is a highly efficient strategy for the radiolabeling of molecules of medicinal interest with technetium and rhenium-tricarbonyl cores. Reaction of azide-functionalized molecules with alkyne prochelators by the Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC; click reaction) enables the simultaneous synthesis and conjugation of tridentate chelating systems for the stable complexation of the radiometals. In many cases, the functionalization of (bio)molecules with the ligand system and radiolabeling can be achieved by convenient one-pot procedures. Since its first report in 2006, Click-to-Chelate has been applied to the development of numerous novel radiotracers with promising potential for translation into the clinic. This review summarizes the use of the Click-to-Chelate approach in radiopharmaceutical sciences and provides a perspective for future applications.

Topics: Chelating Agents; Click Chemistry; Humans; Ligands; Radioactive Tracers; Radiopharmaceuticals; Rhenium; Staining and Labeling; Technetium

PubMed: 23481882
DOI: 10.3390/molecules18033206

Review

Authors: Orazio Schillaci, Manuel Scimeca, Nicola Toschi...

In the era of personalized medicine, the management of oncological patients requires a translational and multidisciplinary approach. During early phases of cancer development, biochemical alterations of cell metabolism occur much before the formation of detectable tumour masses. Current molecular imaging techniques, targeted to the study of molecular kinetics, employ molecular tracers capable of detecting cancer lesions with both high sensitivity and specificity while also providing essential information for both prognosis and therapy. On the contrary, complementary and crucial information is provided by histopathological examination and ancillary techniques such as immunohistochemistry. Thus, the successful collaboration between diagnostic imaging and anatomic pathology can represent a fundamental step in the "tortuous" but decisive path towards personalized medicine.

Topics: Humans; Molecular Imaging; Neoplasms; Precision Medicine; Prognosis; Technetium; Tomography, Emission-Computed, Single-Photon

PubMed: 31354394
DOI: 10.1155/2019/9429761

Authors: Andrea J North, David J Hayne, Christine Schieber...

With the aim of preparing hypoxia-selective imaging and therapeutic agents, technetium(I) and rhenium(I) tricarbonyl complexes with pyridylhydrazone, dipyridylamine, and pyridylaminocarboxylate ligands containing nitrobenzyl or nitroimidazole functional groups have been prepared. The rhenium tricarbonyl complexes were synthesized with short reaction times using microwave irradiation. Rhenium tricarbonyl complexes with deprotonated p-nitrophenyl pyridylhydrazone ligands are luminescent, and this has been used to track their uptake in HeLa cells using confocal fluorescent microscopy. Selected rhenium tricarbonyl complexes displayed higher uptake in hypoxic cells when compared to normoxic cells. A (99m)Tc tricarbonyl complex with a dipyridylamine ligand bearing a nitroimidazole functional group is stable in human serum and was shown to localize in a human renal cell carcinoma (RCC; SK-RC-52) tumor in a mouse.

Topics: Animals; Cell Line, Tumor; Diagnostic Imaging; Electrochemical Techniques; HeLa Cells; Humans; Hypoxia; Ligands; Luminescence; Mice; Mice, Inbred BALB C; Mice, Nude; Microscopy, Fluorescence; Models, Molecular; Molecular Structure; Organometallic Compounds; Rhenium; Technetium; Tissue Distribution

PubMed: 26375592
DOI: 10.1021/acs.inorgchem.5b01691

Authors: Jae-Ho Lee, Shuai Shao, Kenneth T Cheng...

Porphyrin-lipid nanovesicles (PLN) have been developed with intrinsic capabilities as activatable multimodal photonic contrast agents. Radiolabeling of PLN encapsulating drugs could eventually be able to provide quantitative in vivo information for diagnosing and treating diseases. In this study, we developed (99m)Tc-labeled porphyrin-lipid nanovesicles ((99m)Tc-PLN) as a cargo-encapsulated formulation without significant impact on liposome integrity and encapsulation stability. 50 mM calcein was encapsulated into PLN by probe sonication. The size of the PLN was about 150 nm. The PLN were then reacted with (99m)Tc using SnCl2 dissolved in 1 mM HCl as a reducing agent and incubated for 10 min at 22 °C. The radiolabeling efficiency and stability of (99m)Tc-PLN were evaluated by instant thin-layer chromatography and low-pressure liquid chromatography (LPLC). (99m)Tc labeling was successful with a >92% labeling efficiency. LPLC showed that the liposomal elution peaks of the porphyrin-lipid and the calcein overlapped with the radioactivity elution peak of (99m)Tc-labeled PLN. The (99m)Tc-labeling procedure did not change the size of PLN. Encapsulated calcein remained inert inside PLN. Thus, this work lays out a simple and effective radiolabeling method using SnCl2 in HCl in the preparation of (99m)Tc-PLN.

Topics: Lipids; Nanostructures; Porphyrins; Technetium

PubMed: 24963601
DOI: 10.3109/08982104.2014.932379

Review

Authors: Mattia Riondato, Dorotea Rigamonti, Petra Martini...

Technetium-99m is the workhorse of diagnostic nuclear medicine. The aim of the work is to analyze the technetium-99m patents since 2000 to photograph its innovation. QUESTEL's ORBIT Intelligence system was used for the collection of technetium inventions disclosed in patents and patent applications in more than 96 countries in the period 2000-2022; 2768 patent documents were analyzed. Patent counting and analysis have shown that SPECT imaging using technetium-99m radiopharmaceuticals is still robust. The introduction of new technetium-99m radiopharmaceuticals into clinical routine goes beyond successful trials. In eastern economies, such as China and other emerging markets, patent applications are on the rise, while those in developed western countries are stagnating, with some exceptions for the United States. But despite the difficulties, academic and industrial research on these tracers remains essential for the development of nuclear medicine.

Topics: United States; Technetium; Radiopharmaceuticals; Tomography, Emission-Computed, Single-Photon; China

PubMed: 37010457
DOI: 10.1021/acs.jmedchem.3c00148

Authors: Kadriye Busra Karatay, Nihal Dogruoz Gungor, Batu Colak...

Infectious diseases caused by bacteria that have become resistant to antibiotics have increased in prevalence, necessitating new methods for their diagnosis and treatment. The aim of this study was to compare the efficacy of synthetic ciprofloxacin to that of organic ciprofloxacin produced by cave microorganisms, as well as to evaluate the feasibility of using organic ciprofloxacin radiolabeled with technetium-99m as an imaging agent. Organic ciprofloxacin produced by cave bacteria isolated from sediment taken from the dark zone of Antalya's "Yark Sinkhole," (Turkey's 14th deepest cave), was purified using high-performance liquid chromatography. Purified organic ciprofloxacin and standard ciprofloxacin were radiolabeled with technetium-99m (99mTc), and their uptake by pathogenic microorganisms as well as potential as an imaging agent were examined. According to thin-layer radiochromatography, radiolabeling efficiencies were 98.99 ± 0.34 (n = 7) and 91.25 ± 1.84 (n = 7) for radiolabeled organic ciprofloxacin and standard ciprofloxacin respectively. The binding efficiency of radiolabeled organic ciprofloxacin at the 240th minute was higher compared with radiolabeled standard ciprofloxacin, especially with P.aeruginosa, MRSA, VRE and E.coli. The results demonstrate that radiolabeling with 99mTc does not alter the biological behavior of organic ciprofloxacin, and radiolabeled organic ciprofloxacin has potential as an imaging agent for the detection of bacterial infection. The original value of the study is the monitoring of the antibiofilm effects of untouched cave-derived organic antibiotics by radiolabeling with a radionuclide.

Topics: Ciprofloxacin; Technetium; Radiopharmaceuticals; Radionuclide Imaging; Anti-Bacterial Agents; Escherichia coli

PubMed: 37943851
DOI: 10.1371/journal.pone.0291342