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Judite Costa

Bio: Judite Costa is an academic researcher from University of Lisbon. The author has contributed to research in topics: Protonation & Metal ions in aqueous solution. The author has an hindex of 19, co-authored 43 publications receiving 861 citations. Previous affiliations of Judite Costa include University of Nebraska–Lincoln & Instituto Superior Técnico.

Papers
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TL;DR: Some macrocyclic compounds containing pyridinc have been synthetized: 3,6,9,15-tetraazabicyclo[9.3.1]hexadeca-1(16),12,14-triene(2), 3,7,11,17-TTEBICCLO[11.3 as mentioned in this paper, 13,15 trienc (4).
Abstract: Some macrocyclic compounds containing pyridinc have been synthetized: 3,6,9,15-tetraazabicyclo[9.3.1]pentadeca1(15),11,13-triene(1), 3,7,10,16-tetraazabicyclo[10.3.1]hexadeca-1(16),12,14-triene(2), 3,7,11,17-tetraazabicyclo[11.3.1]heptadeca-1(17),13,15-triene (3), and 7-methyl-3,7,11,17-tetraazabicyclo[11.3.1]heptadeca-1(17),13,15 trienc (4). The protonation reactions of these ligands were studied by potentiometric and 1 H NMR techniques

97 citations

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TL;DR: In this article, a linear correlation between the dissociation constants of polyaza and polyoxa-polyaza macrocyclic compounds was established between the acid forms obtained in deuterium oxide (p K D ) and in water ( p K H ).

90 citations

Journal ArticleDOI
TL;DR: Five macrocyclic copper(II) complexes are synthesized and evaluated their ability to scavenge the superoxide anions generated by the xanthine-xanthine oxidase system, finding some of the presented complexes appear to be promising superoxide scavenger agents, and should be considered for further biological assays.

62 citations

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TL;DR: Biodistribution studies in mice demonstrated that (153)Sm/(166)Ho-trita complexes have a fast tissue clearance with more than 95% of the injected activity excreted after 2 h, value that is comparable to the corresponding dota complexes, in contrast, the ( 153)Sm-teta complex has a significantly lower total excretion.

61 citations

Journal ArticleDOI
TL;DR: In this paper, the protonation constants of two series of tetraazamacrocyclic ligands with acetate and methylphosphonate pendant arms, as well as their stability constants with Cu 2+, La 3+, Sm 3+ and Ho 3+ were determined.
Abstract: The protonation constants of two series of tetraazamacrocyclic ligands with acetate and methylphosphonate pendant arms, as well as their stability constants with Cu 2+ , La 3+ , Sm 3+ , and Ho 3+ , were determined. All the values were determined in aqueous solution at 298.0 K and 0.10 mol dm -3 in N(CH 3 ) 4 NO 3 . In the first series, the effect of both types of pendant arms was observed by appending them in the same macrocyclic backbone, a 14-membered tetraazamacrocycle containing pyridine (ac 3 py14, p 2 py14, and p 3 py14). In the second series, two effects were taken into account, the increase of the cavity size of the macrocycle, from 12- to 14-membered, and the appending of acetate (dota, trita, and teta) or methylphosphonate (dotp, tritp, and tetp) arms. The ligands containing methylphosphonate arms have higher thermodynamic stability compared to the corresponding ones with acetate arms, especially in the series of compounds containing pyridine, even upon correction of the different basicity values of the ligands. On the other hand, the ligands with smaller macro- cyclic cavity size, namely, dota and dotp, exhibit the largest values of stability constants. In contrast, ac 3 py14 presents low stability constants with lanthanides. An interpretation of these features based on the known adopted arrangement of dota and teta when free or coordinated with lanthanides is evaluated.

45 citations


Cited by
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TL;DR: SPECT and PET technology has been around for decades, but its use remained limited because of the limited availability of relevant isotopes which had to be produced in nuclear reactors or particle accelerators, but the introduction of the small biomedical cyclotron, the self-contained radionuclide generator and the dedicated small animal or clinical SPECT andPET scanners to hospitals and research facilities has increased the demand for SPect and PET isotopes.
Abstract: Molecular imaging is the visualization, characterization and measurement of biological processes at the molecular and cellular levels in humans and other living systems. Molecular imaging agents are probes used to visualize, characterize and measure biological processes in living systems. These two definitions were put forth by the Sociey of Nuclear Medicine (SNM) in 2007 as a way to capture the interdisciplinary nature of this relatively new field. The emergence of molecular imaging as a scientific discipline is a result of advances in chemistry, biology, physics and engineering, and the application of imaging probes and technologies has reshaped the philosophy of drug discovery in the pharmaceutical sciences by providing more cost effective ways to evaluate the efficacy of a drug candidate and allowing pharmaceutical companies to reduce the time it takes to introduce new therapeutics to the marketplace. Finally the impact of molecular imaging on clinical medicine has been extensive since it allows a physician to diagnose a patient’s illness, prescribe treatment and monitor the efficacy of that treatment non-invasively. Single Photon Emission Computed Tomography (SPECT) and Positron Emission Tomography (PET) were the first molecular imaging modalities used clinically. SPECT requires the use of a contrast agent labeled with a gamma emitting radionuclide, which should have an ideal gamma energy of 100-250 keV. These gamma rays are recorded by the detectors of a dedicated gamma camera or SPECT instrument and after signal processing can be converted into an image indentifying the localization of the radiotracer. PET requires the injected radiopharmaceutical to be labeled with a positron emitting radionuclide. As the radionuclide decays it ejects a positron from its nucleus which travels a short distance before being annihilated with an electron to release two 511 keV gamma rays 180° apart that are detected by the PET scanner (Figure 1). After sufficient acquisition time the data are reconstructed using computer based algorithms to yield images of the radiotracer’s location within the organism. When compared to SPECT, PET has greater advantages with respect to sensitivity and resolution and has been gaining in clinical popularity, with the number of PET-based studies expected to reach 3.2 million by 2010.1 While SPECT and PET technology has been around for decades, its use remained limited because of the limited availability of relevant isotopes which had to be produced in nuclear reactors or particle accelerators. However, the introduction of the small biomedical cyclotron, the self-contained radionuclide generator and the dedicated small animal or clinical SPECT and PET scanners to hospitals and research facilities has increased the demand for SPECT and PET isotopes. Figure 1 Cartoon depicting the fundamental principle of Positron Emission Tomography (PET). As the targeting group interacts with the cell surface receptor, the positron emitting radio-metal decays by ejecting β+ particles from its nucleus. After traveling ... Traditional PET isotopes such as 18F, 15O, 13N and 11C have been developed for incorporation into small molecules, but due to their often lengthy radio-syntheses, short half-lives and rapid clearance, only early time points were available for imaging, leaving the investigation of biological processes, which occur over the duration of hours or days, difficult to explore. With the continuing development of biological targeting agents such as proteins, peptides, antibodies and nanoparticles, which demonstrate a range of biological half-lives, a need arose to produce new radionuclides with half-lives complementary with their biological properties. As a result, the production and radiochemistry of radiometals such as Zr, Y, In, Ga and Cu have been investigated as radionuclide labels for biomolecules since they have the potential to combine their favorable decay characteristics with the biological characteristics of the targeting molecule to become a useful radiopharmaceutical (Tables ​(Tables11 and ​and22).2 Table 1 Gamma- and Beta-Emitting Radiometals Table 2 Positron-Emitting Radiometals The number of papers published describing the production or use of these radiometals continues to expand rapidly, and in recognition of this fact, the authors have attempted to present a comprehensive review of this literature as it relates to the production, ligand development and radiopharmaceutical applications of radiometals (excluding 99mTc) since 1999. While numerous reviews have appeared describing certain aspects of the production, coordination chemistry or application of these radiometals,2-18 very few exhaustive reviews have been published.10,12 Additionally, this review has been written to be used as an individual resource or as a companion resource to the review written by Anderson and Welch in 1999.12 Together, they provide a literature survey spanning 50 years of scientific discovery. To accomplish this goal, this review has been organized into three sections: the first section discusses the coordination chemistry of the metal ions Zr, Y, In, Ga and Cu and their chelators in the context of radiopharmaceutical development; the second section describes the methods used to produce Zr, Y, In, Ga and Cu radioisotopes; and the final section describes the application of these radiometals in diagnostic imaging and radiotherapy.

768 citations

Journal ArticleDOI
TL;DR: An overview of potentiometric sensors that are capable of detecting toxic heavy metal ions in environmental samples is presented and discussed and several limitations do exist in terms of selectivity, limits of detection, dynamic ranges, applicability to specific problems, and reversibility.
Abstract: An overview of potentiometric sensors that are capable of detecting toxic heavy metal ions in environmental samples is presented and discussed. Notwithstanding the tremendous work performed so far,...

533 citations

Journal ArticleDOI
TL;DR: The ligand types and structures of their complexes on one side and a set of the physico-chemical parameters governing properties of the CAs on the other side are discussed and the solid-state structures of lanthanide(III) complexes of open-chain and macrocyclic ligands and their structural features are compared.
Abstract: Magnetic resonance imaging is a commonly used diagnostic method in medicinal practice as well as in biological and preclinical research. Contrast agents (CAs), which are often applied are mostly based on Gd(III) complexes. In this paper, the ligand types and structures of their complexes on one side and a set of the physico-chemical parameters governing properties of the CAs on the other side are discussed. The solid-state structures of lanthanide(III) complexes of open-chain and macrocyclic ligands and their structural features are compared. Examples of tuning of ligand structures to alter the relaxometric properties of gadolinium(III) complexes as a number of coordinated water molecules, their residence time (exchange rate) or reorientation time of the complexes are given. Influence of the structural changes of the ligands on thermodynamic stability and kinetic inertness/lability of their lanthanide(III) complexes is discussed.

469 citations

Journal ArticleDOI
TL;DR: The use of such complexes in imaging as MRI contrast agents, radiopharmaceuticals and luminescent probes is discussed, and the considerable scope for future development of novel metal based therapeutics based on protein binding, targeting of radioisotopes or dual function agents is highlighted.

259 citations

Journal ArticleDOI
TL;DR: Fundamental concepts of drug design and applications are introduced, with particular emphasis on bifunctional chelators (BFCs), which ensure secure consolidation of the radiometal and targeting vector and are integral for optimal drug performance.
Abstract: Radiometals possess an exceptional breadth of decay properties and have been applied to medicine with great success for several decades. The majority of current clinical use involves diagnostic procedures, which use either positron-emission tomography (PET) or single-photon imaging to detect anatomic abnormalities that are difficult to visualize using conventional imaging techniques (e.g., MRI and X-ray). The potential of therapeutic radiometals has more recently been realized and relies on ionizing radiation to induce irreversible DNA damage, resulting in cell death. In both cases, radiopharmaceutical development has been largely geared toward the field of oncology; thus, selective tumor targeting is often essential for efficacious drug use. To this end, the rational design of four-component radiopharmaceuticals has become popularized. This Review introduces fundamental concepts of drug design and applications, with particular emphasis on bifunctional chelators (BFCs), which ensure secure consolidation of the radiometal and targeting vector and are integral for optimal drug performance. Also presented are detailed accounts of production, chelation chemistry, and biological use of selected main group and rare earth radiometals.

257 citations