Microwave-assisted solid-phase synthesis of nicotinyl hydrazones for use in radiochemistry of technetium-99m

We report a new method for efficient and rapid synthesis of HYNIC-hydrazone derivatives using microwaveassisted solid-phase. In comparison to the conventional heating procedure, microwave irradiation considerably accelerated the formation of HYNIC analogues. The synthesis time and efforts are significantly reduced in the present method, without side product formation. We proved that the HYNIC-hydrazone clustering can be directly labeled with technetium without exposing the free hydrazine group. Therefore, this is a useful tool to obtain HYNIC-bioconjugates for use in 99mTc radiochemistry

Mannose receptor 1 expression does not determine the uptake of high-density mannose dendrimers by activated macrophages populations

The presence of a high number of macrophages within solid tumors is often significantly associated with poor prognosis and predict treatment failure for chemotherapy and radiotherapy. Macrophages are innate immune cells capable of performing diverse functions depending on the different signals from the microenvironment. The classically activated macrophage is commonly present during the early stages of tumor development while alternatively activated macrophages are associated with more advanced tumors. The distinction of the antitumoral macrophages from the pro-tumoral macrophages is not absolute. However, they have different cell surface markers such as mannose receptor (MRC1 or CD206) abundantly expressed by macrophages treated with interleukin-4 (IL-4). The important roles of macrophages in cancers suggest that it is important to develop novel therapies that target these cells. In the present study, we designed a probe using Polyamidoamine (PAMAM) fifth-generation (G5) dendrimers conjugated with mannose, Cyanine 7 (Cy7), and hydrazinonicotinamide (HYNIC) for target macrophages with high expression of MRC1 in the tumor. The intracellular uptake of 99mTc-HYNIC-dendrimer-mannose-Cy7 through the interaction with MRC1 in bone marrow-derived macrophages (BMDMs) untreated or treated with lipopolysaccharides (LPS) + interferon (IFN)γ or IL-4 was analyzed. Our results show that high-density mannose dendrimers are preferentially bound by macrophages treated by IFNγ and LPS that express lower levels of MRC1 than for macrophages treated by IL-4 that express high levels of MRC1. Furthermore, the intracellular 99mTc-HYNIC-dendrimer-mannose-Cy7 uptake in BMDMs was not inhibited in the presence of free mannose or glucose. This result suggests that 99mTc-HYNIC-dendrimer-mannose-Cy7 is not internalized via macrophage MRC1. Based on these findings, we concluded that MRC1 expression does not determine the uptake of high-density mannose dendrimers

Preliminary in vivo characterization of a theranostic aptamer: Sgc8-c- DOTA-67Ga

Nucleic acid aptamers can recognise their target with high affinity and specificity, and their potential as molecular imaging agents and use in theranostics are being explored. Compared with antibodies, aptamers can be easily synthesized and chemically modified, rendering them a valuable tool for in vivo approaches. Herein, we investigated a 41nt DNA aptamer as a theranostic agent for lymphoma and melanoma. This aptamer exhibits specific binding and high affinity for the PTK7 receptor that is overexpressed in many cancer cells. A 5’-amino-derivative of the Sgc8-c aptamer was bound to the metal chelator DOTA (1,4,7,10-tetraazacyclododecane- 1,4,7,10-tetraacetic acid) and labelled with the radionuclide 67Ga, forming the aptamer probe Sgc8- c-DOTA-67Ga. Different conditions during synthesis, purification and identification of the intermediate and final radiolabelled probe, were examined. Aptamer modification and radiolabelling were performed with high yields, resulting in a probe that was stable in neutral buffered solution. Binding to PTK7 was studied in CCRFCEM, A20 and B16F1 cell lines, and in purified PTK7-1 receptor, to confirm specificity. The in vitro cell lines showed different levels of uptake, and the signal increased over time. In vivo binding properties were studied in A20 and B16F10 tumour-bearing mice and images were acquired using X-rays and gamma imaging modalities for both models. Preliminary results in both tumour models showed good aptamer uptake by tumour. Hepatobiliar metabolism was observed with Sgc8-c-DOTA-67Ga and no signal was detected in normal tissue. In summary, these results support the utility of labelled aptamers as theranostic agents in different imaging modalities and theranostic

Development and Evaluation of 2-Amino-7-Fluorophenazine 5,10-Dioxide Polymeric Micelles as Antitumoral Agents for 4T1 Breast Cancer

2-Amino-7-fluorophenazine 5,10-dioxide (FNZ) is a bioreducible prodrug, poorly soluble in water, with potential anticancer activity on hypoxic-tumors. This poor solubility limits its potential applications in clinic. Amphiphilic pristine polymeric micelles (PMs) based on triblock copolymers Pluronic® and Tetronic®, glycosylated derivatives and their mixtures with preformed-liposomes (LPS), were analyzed as strategies to improve the bioavailability of FNZ. FNZ encapsulations were performed and the obtaining nanostructures were characterized using UV-visible spectroscopy (UV- VIS), Transmission Electron Microscopy (TEM), Fourier transform infrared analysis and Dynamic Light Scattering (DLS). The most promising nanoformulations were analyzed for their potential toxicity and pharmacologically, at 20 mg/kg FNZ-doses, in a stage-IV murine metastatic-breast tumor model. The results revealed that the solubility of the encapsulated-FNZ increased up to seven times and the analysis (UV-VIS, DLS and TEM) confirmed the interaction between vehicles and FNZ. In all the cases appropriate encapsulation efficiencies (up to 70%), monodisperse nanometric particle sizes (PDI = 0.180–0.335), adequate Z-potentials (-1.59 to -26.4 mV), stabilities and spherical morphologies were obtained. The in vitro profile of FNZ controlled releases corresponded mainly to a kinetic Higuchi model. The in vitro/in vivo biological studies revealed non-toxicity and relevant tumor-weight diminution (up to 61%).Fil: Lecot, Nicole. Universidad de la República; UruguayFil: Dávila Belzunce, María Belén. Universidad de la República; UruguayFil: Sánchez, Carina. Universidad de la República; UruguayFil: Fernández, Marcelo. Universidad de la República; UruguayFil: González, Mercedes. Universidad de la República; UruguayFil: Cabral, Pablo. Universidad de la República; UruguayFil: Cerecetto, Hugo. Universidad de la República; UruguayFil: Glisoni, Romina Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Nanobiotecnología. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Nanobiotecnología; Argentin

In vitro and in vivo uptake studies of PAMAM G4.5 dendrimers in breast cancer

Background: Breast cancer is the second leading cause of cancer death worldwide. Nanotechnology approaches can overcome the side effects of chemotherapy as well as improve the efficacy of drugs. Dendrimers are nanometric size polymers which are suitable as drug delivery systems. To the best of our knowledge, studies on the application of PAMAM G4.5 (polyamidoamine half generation 4) dendrimers as potential drug delivery systems in breast cancer have not been reported. In this work we developed a PAMAM G4.5 dendrimer containing FITC (fluorescein isothiocyanate) dye to study their uptake by murine breast cancer cells and BALB/c mice breast tumors. Results: We performed a reaction between FITC and PAMAM G4.5 dendrimers which were previously derivatized with piperazine (linker molecule), characterized them by 1H NMR (proton nuclear magnetic resonance) spectroscopy and MALDI-TOF (matrix-assisted laser desorption/ionization- time-of-flight) mass spectrometry. The experimental data indicated that 2 FITC molecules could be bound covalently at the PAMAM G4.5 dendrimer surface, with 17 FITC molecules probably occluded in PAMAM dendrimers cavity. PAMAM-FITC dendrimer (PAMAM G4.5-piperazinyl-FITC dendrimer) size distribution was evaluated by DLS (dynamic light scattering) and TEM (transmission electron microscopy). The nanoparticle hydrodynamic size was 96.3 ± 1.4 nm with a PdI (polydispersion index) of 0.0296 ± 0.0171, and the size distribution measured by TEM was 44.2 ± 9.2 nm. PAMAM-FITC dendrimers were neither cytotoxic in 4T1 cells nor hemolytic up to 24 h of incubation. In addition, they were uptaken in vitro by 4T1 cells and in vivo by BALB/c mice breast tumors. PAMAM G4.5-piperazinyl-FITC dendrimer intracellular distribution was observed through histologic analysis of the tumor by laser confocal microscopy. Conclusion: These results indicate that PAMAM G4.5 dendrimers enter tumor tissue cells, being good candidates to be used as antitumor drug delivery systems for breast cancer treatment and diagnosis

Development and evaluation of 2-amino-7-fluorophenazine 5,10-dioxide polymeric micelles as antitumoral agents for 4T1 breast cancer

2-Amino-7-fluorophenazine 5,10-dioxide (FNZ) is a bioreducible prodrug, poorly soluble in water, with potential anticancer activity on hypoxic-tumors. This poor solubility limits its potential applications in clinic. Amphiphilic pristine polymeric micelles (PMs) based on triblock copolymers Pluronic® and Tetronic®, glycosylated derivatives and their mixtures with preformed-liposomes (LPS), were analyzed as strategies to improve the bioavailability of FNZ. FNZ encapsulations were performed and the obtaining nanostructures were characterized using UV-visible spectroscopy (UV-VIS), Transmission Electron Microscopy (TEM) and Dynamic Light Scattering (DLS). The most promising nanoformulations were analyzed for their potential toxicity and pharmacologically, at 20 mg/kg FNZ-doses, in a stage-IV murine metastatic-breast tumor model. The results revealed that the solubility of the encapsulated-FNZ increased up to 14 times and the analysis (UV-VIS, DLS and TEM) confirmed the interaction between vehicles and FNZ. In all the cases appropriate encapsulation efficiencies (greater than 75%), monodisperse nanometric particle sizes (PDI = 0.180–0.335), adequate Z-potentials (−1.59 to −26.4 mV), stabilities and spherical morphologies were obtained. The in vitro profile of FNZ controlled releases corresponded mainly to a kinetic Higuchi model. The in vitro/in vivo biological studies revealed non-toxicity and relevant tumor-weight diminution (up to 61%).ANII: FCE_1_2014_1_104714ANII: POS_FCE_2015_1_100519

Luteinizing hormone-releasing hormone (LHRH): potential agent of molecular oncology

La hormona liberadora de la hormona luteinizante es un decapéptido producido por el hipotálamo y posee un rol fundamental en la regulación del eje pituitario/gonadal y en el ciclo ovárico. Es capaz de unirse a receptores específicos sobre las células gonadales para regular la síntesis y secreción de las hormonas gonadotróficas, las hormonas luteinizante y folículo estimulante. A su vez, se ha comprobado que receptores específicos de la hormona liberadora de la hormona luteinizante se encuentran sobreexpresados en cáncer mama, próstata, ovárico, entre otros; lo cual ha permitido su utilización, tanto de análogos como agonistas, en terapia para estas neoplasias, principalmente en cáncer de próstata y mama. Por lo anterior, nos planteamos desarrollar y optimizar la marcación con el radionucléido emisor gamma, el 99m-Tecnecio, del péptido LHRH, a modo de evaluar su potencial empleo como agente de imagen molecular en oncología. Para esto, el HYNIC-GSG-LHRH fue adquirido comercialmente. La marcación con 99mTc fue realizada a 50 ºC en presencia de diferentes co-ligandos incluyendo Tricina, Ácido etilendiaminodiacético, Tricina/Ácido etilendiaminodiacético y Tricina/Ácido Nicotínico. Las condiciones de marcación (pH, concentración de coligandos, concentración de agente reductor (cloruro de estaño), temperatura y tiempo de reacción fueron optimizadas en orden, para estandarizar el procedimiento. Se evaluaron las purezas radioquímicas por HPLC. Tanto los coeficientes de partición (Log P) y la estabilidad in vitro fueron determinadas a modo de obtener un agente de imagen estable y de alta pureza radioquímica. Se realizaron estudios biológicos in vitro de afinidad en distintas líneas celulares humanas de mama y próstata (MDA-MB-231, MCF-7 y MDA-MB-435) y próstata (PC3, LnCap y Du-145), así como su perfil de biodistribución en modelos murinos; a modo de obtener una aproximación al comportamiento biológico del nuevo radiotrazador. Logramos marcar el conjugado HYNIC-GSG-LHRH con 99m-Tecnecio, empleando altas actividades específicas usando como co-ligandos tanto Tricina como la mezcla Tricina/Ácido Nicotínico, obteniendo altas purezas radioquímicas (> 95%), alta estabilidad in vitro y baja lipofilicidad (Log P de -2,5 ± 0,05 y -2,82 ± 0,04, empleando Tricina y Tricina/Ácido Nicotínico, respectivamente). El conjugado [99mTc]-HYNIC-GSG-LHRH/Tricina-Ácido Nicotínico reveló elevada afinidad de unión específica por los receptores de la hormona liberadora de la hormona luteinizante expresados en las líneas celulares de mama y próstata. Se observó que el complejo radiomarcado presenta un perfil de biodistribución óptimo para ser empleado como potencial agente de imagen.Luteinizing hormone-releasing hormone is a decapeptide produced by the hypothalamus and has a fundamental role in the regulation of the pituitary/gonadal axis and in the ovarian cycle. It is able to bind to specific receptors on gonadal cells to regulate the synthesis and secretion of gonadotrophic hormones, luteinizing hormones and follicle stimulating hormones. In turn, it has been shown that specific receptors of the hormone releasing luteinizing hormone are overexpressed in breast, prostate, ovarian cancer, among others; which has allowed its use, both analogues and agonists, in therapy for these neoplasms, mainly in prostate and breast cancer. Therefore, we propose to develop and optimize the gamma emitting radionuclide labeling, 99m-Technetium, of the LHRH peptide, in order to assess its potential use as a molecular imaging agent in oncology. For this purpose, the HYNIC-GSG-LHRH was purchased commercially. The 99mTc labeling was performed at 50°C in the presence of different co-ligands including Tricine, Ethylenediamine diacetic acid, Tricine/Ethylenediamine diacetic acid and Tricine/Nicotinic acid. The marking conditions (pH, concentration of co-ligands, concentration of the reducing agent (tin chloride), temperature and reaction time) were optimized in order to standardize the procedure. The radiochemical purities were evaluated by HPLC. Both the partition coefficients (Log P) and in vitro stability were determined in order to obtain a stable imaging agent of high radiochemical purity. In vitro biological affinity studies were performed in different human breast and prostate cell lines (MDA-MB-231, MCF-7 and MDA-MB-435) and prostate (PC3, LnCap and Du-145), as well as their profile of biodistribution in murine models; in order to obtain an approximation to the biological behavior of the new radiotracer. We managed to label the conjugate HYNIC-GSG-LHRH with 99m-Tecnecio, using high specific activities using as co-ligands both Tricine and the Tricine/ Nicotinic Acid mixture, obtaining high radiochemical purities (> 95%), high stability in vitro and low lipophilicity (Log P of -2,5 ± 0,05 and -2,82 ± 0,04, using Tricine and Tricine/Nicotinic Acid, respectively). The [99mTc] -HYNIC-GSG-LHRH/Tricine-Nicotinic Acid conjugate revealed a high specific binding affinity for the luteinizing hormone-releasing hormone receptors expressed in the breast and prostate cell lines. It was observed that the radiolabeled complex presents an optimal biodistribution profile to be used as a potential imaging agent

99mTc-HYNIC-Fab (Bevacizumab): potencial agente de imagen para diagnóstico de Linfoma No Hodgkin

El factor de crecimiento endotelial vascular (VEGF), es un factor clave en la angiogénesis tumoral de muchos tipos de tumores, incluyendo el Linfoma No Hodgkin (LNH). El objetivo del presente trabajo es la radiomarcación de los fragmentos de unión al antígeno (Fab) del anticuerpo monoclonal Bevacizumab con 99mTc y su evaluación como potencial agente de imagen para LNH. Para lograrlo se analizó la expresión de VEGF mediante citometría de flujo en una línea celular de LNH (Toledo). La fragmentación se realizó empleando papaína y los Fab obtenidos fueron conjugados con NHS-HYNIC-Tfa y radiomarcados con 99mTc. La pureza radioquímica y la estabilidad fueron ensayadas. Se realizaron estudios de biodistribución tanto en ratones sanos como en portadores de LNH. Se observó que las células Toledo presentaron una elevada expresión de VEGF. El radiomarcaje se realizó de forma rápida, sencilla, reproducible y estable, con purezas radioquímicas >90%. Los estudios de biodistribución revelaron una significativa captación renal y tumoral, indicando que la principal vía de eliminación es renal. De los resultados obtenidos se concluye que el 99mTc-HYNIC-Fab (Bevacizumab) representa un potencial a agente de imagen de la expresión de VEGF asociada a LNH

Development of fluorescent- and radio-traceable T1307-polymeric micelles as biomedical agents for cancer diagnosis: biodistribution on 4T1 tumor-bearing mice

Abstract In recent years, nanocarriers have been studied as promising pharmaceutical tools for controlled drug-delivery, treatment-efficacy follow-up and disease imaging. Among them, X-shaped amphiphilic polymeric micelles (Tetronic®, poloxamines) display great potential due to their biocompatibility and non-toxic effects, among others. In the present work, polymeric micelles based on the T1307 copolymer were initially decorated with a 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY)-fluorophore in order to determinate its in vivo biodistribution on 4T1 tumor-bearing mice. However, unfavorable results with this probe led to two different strategies. On the one hand, the BODIPY-micelle-loaded, L-T1307-BODIPY, and on the other hand, the 99mTc-micelle-radiolabeled, L-T1307- 99m Tc, were analyzed separately in vivo. The results indicated that T1307 accumulates mainly in the stomach, the kidneys, the lungs and the tumor, reaching the maximum organ-accumulation 2 hours after intravenous injection. Additionally, and according to the results obtained for L-T1307- 99m Tc, the capture of the polymeric micelles in organs could be observed up to 24 hours after injection. The results obtained in this work were promising towards the development of new radiotracer agents for breast cancer based on X-shaped polymeric micelles

The Multipurpose Interferometric Array and the development of its technological demonstrator

We present a proposal for the construction and development of a new instrument for radio astronomical observations based on interferometric techniques, that will provide high angular resolution in the 21 cm band, with the intention of improving and extending the current performance of the instruments used at the Argentine Institute of Radio Astronomy. This will allow internationally competitive scientific research and the acquisition of cutting-edge scientific and technological know-how in the aforementioned techniques, enabling interferometric measurements and the development of very long baseline or VLBI techniques. This project is called MIA, an acronym for “Multipurpose Interferometric Array”.Fil: Gancio Gonzalez, Guillermo Matias. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Romero, Gustavo Esteban. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Benaglia, Paula. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: González, J. M.. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Rasztocky, Emiliano. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Command, Juan Hugo Cesar. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Valdez, Gaston Alejandro. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Tarcetti, Ana Evelina Yael. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Hauscarriaga, Fernando Pablo. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Alarcon, Pablo Javier. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Aquino, Esteban Facundo. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Alí, Maximiliano Andrés. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Capuccio, Darío. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Cabral, Luca Federico. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Contreras, Matias Lautaro. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Diaz, Eliseo David. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Duarte, Nahuel. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Garcia, Leandro Manuel. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Perilli, Daniel Oscar. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Otonello, Pablo. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Spagnolo, Santiago Javier. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaProspects for low-frequency Radio Sstronomy in South AmericaCiudad Autónoma de Buenos AiresArgentinaConsejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomí