Communities in DSpace
Select a community to browse its collections.
Recent Submissions
Dosimetry and preclinical evaluation of longterm radiotoxicity following treatment with 212Pb alpha-radioimmunotherapy targeting CD20
(2025-12-05) Quelven, Isabelle; Saidi, Amal; Sage, Magali; Mora Ramirez, Erick; Torgue, Julien; Cogne, Michel; Durand Panteix, Stéphanie
Background Radioimmunotherapy (RIT) with α-emitters represents an attractive alternative for the treatment of refractory Non-Hodgkin lymphoma (NHL) due to the high linear energy transfer and short path length of α-radiation in tissues. We have previously shown that α-RIT with [212Pb]Pb-TCMC-rituximab is potentially useful for treatment of NHL. In this study, we performed radiation dosimetry and evaluated the long-term toxicity in mice to determine safety of [212Pb]Pb-TCMC-rituximab,.
Results Biodistribution data obtained after intravenous administration of [212Pb]Pb-TCMC-rituximab (185 kBq) in healthy mice were used to calculate the absorbed radiation doses from [212Pb]Pb-TCMC-rituximab. Analyses show that the alveolar-interstitial, kidneys, and spleen receive the highest dose.
In order to evaluate the toxicity of RIT for up to 9 months, [212Pb]Pb-TCMC-rituximab was administered intravenously in healthy C57BL/6 mice (277.5 and 555 kBq) and in a B-NHL immunocompetent mouse model (277.5 kBq, specific activity of 37 or 370 MBq/mg). Our previous study revealed a high efficacy of [212Pb]Pb-TCMCrituximab at 277.5 kBq and that activities of 185–370 kBq of [212Pb]Pb-TCMC-rituximab were well-tolerated. However, in this long-term study, toxicity emerged in healthy mice after four months. The median survival for the 277.5 and 555 kBq groups were 189 and 161 days, respectively. There was no significant hepatic toxicity, but there was a significant increase in urea and creatinine levels at 6 months, indicating long-term renal toxicity (p <0.001). These results were supported by histopathological data. Long-term renal toxicity is also observed in the toxicity study performed on tumor model with two specific activities of [212Pb]Pb-TCMC-rituximab. Nevertheless, this toxicity was reduced at 370 MBq/mg compared to 37 MBq/mg.
Conclusion This study shows that long-term toxicity is induced by [212Pb]Pb-TCMC-rituximab, particularly affecting the kidneys. However, it highlights that this renal toxicity can be reduced through optimization, possibly by modifying the specific activity of the treatment.
Mining liabilities as a source of toxic metals and physicochemical contaminants in tropical rivers
(2026-01) Rojas Conejo, Johanna; Picado Pavón, Francisco; van Gestel, Cornelis A. M.; Suárez Serrano, Andrea; Parra Barrientos, Nicole; Quesada Román, Adolfo; Guillén Watson, Anny; López Maietta, María
Global mining activities have led to widespread river pollution, jeopardizing aquatic ecosystems and human well-being by releasing harmful contaminants. The mining liabilities left by a company after ending its activity in 1990 have resulted in the environmental release of metals in surrounding rivers in Líbano de Tilarán, Guanacaste, northern Costa Rica. We examined whether the metal concentrations in water and sediment affected by these mining liabilities are exposure sources for benthic macroinvertebrates in the San José and Cañas rivers. The metal concentrations in these organisms were related to the spatial distribution of exposure concentrations. We also assessed spatial changes in the physicochemical water characteristics due to the direct influence of mining liabilities. Arsenic, cadmium and lead concentrations in water were below the limits of quantification (2–4 μg/L), but in sediments high concentrations were found which were related to seasonal variations in river discharge. The high concentrations of arsenic and lead in the sediments of the San José River explained the low number of macroinvertebrate families, with smaller individuals (<0.4 mg dry weight) of the Leptohyphidae family showing higher average concentrations of arsenic (10.6 μg/g), cadmium (1.25 μg/g) and lead (1.30 μg/g) than larger individuals (>0.4 mg, dry weight) of the same family. The enrichment of sediments with metals, together with their heterogeneous spatial distribution, makes the benthic macroinvertebrates more exposed especially to arsenic, which may reduce their abundance, survival, and growth. The strong correlation between the spatial distribution of metal concentrations in sediments and their accumulation in benthic organisms, alongside changes in water quality, demonstrates the impact of mining liabilities on the San José and Cañas rivers.
Venom variation and ontogenetic changes in the Crotalus molossus complex: insights into composition, activities, and antivenom neutralization
(2025-04) Miguel, Borja; Castañeda Gaytán, Gamaliel; Alagon, Alejandro; Strickland, Jason L.; Parkinson, Christopher L.; Gutiérrez Martínez, Areli; Rodriguez Lopez, Bruno; Zarzosa, Vanessa; Lomonte, Bruno; Saviola, Anthony J.; Fernández, Julián; Smith, Cara Francesca; Hansen, Kirk Charles; Pérez Robles, Armando; Castañeda Pérez, Sebastián; Hirst, Samuel R.; Olvera Rodríguez, Felipe; Fernández Badillo, Leonardo; Sigala, Jesús; Jones, Jason; Montaño Ruvalcaba, Carlos; Ramírez Chaparro, Ricardo; Margres, Mark J.; Acosta Campaña, Gerardo; Neri Castro, Edgar
The Crotalus molossus complex consists of five to seven phylogenetically related lineages of black-tailed rattlesnakes widely distributed in Mexico. While previous studies have noted venom variation within specific lineages of the Crotalus molossus complex, a comprehensive characterization of interspecific and ontogenetic venom variations, their functional implications, and the neutralizing ability of the Mexican antivenom against these variants remains largely unexamined. Herein, using two proteomic approaches for five lineages (C. basiliscus, C. m. molossus, C. m. nigrescens, C. m. oaxacus, and C. ornatus) of the C. molossus complex we characterized the number of toxins and their relative abundance in the venom of individuals of varying sizes. All five lineages undergo ontogenetic venom composition shifts associated with snake length. However, the pattern of ontogenetic shifts varied among lineages. In some lineages, these shifts led to significant differences in proteolytic, phospholipase A2, and fibrinogenolytic activities. Venom in smaller C. basiliscus, C. m. nigrescens, and C. m. oaxacus individuals had lower LD50 values (more lethal) in mice. Whereas the venom lethality of C. m. nigrescens (both juvenile and adult) and C. m. oaxacus (adult) was several times higher in a mammalian (mouse) model than in a reptilian (iguana) model. Antivipmyn® showed different neutralizing potencies toward venom pools. Overall, our results indicated that even among closely related rattlesnake lineages, venom phenotypes may vary greatly, impacting their function and the efficacy of antivenom neutralization.
Costa Rica aprende con la U Pública: promoviendo el acercamiento y la vinculación de la Universidad Pública con la comunidad nacional
(2023-12) Gamboa Jiménez, Ana Gabriela; Mc Quiddy-Padilla, Evelyn; León Boza, Ileana; Vargas Valladares, Isabel; Jiménez Chavarría, Silvia; Vargas González, Víctor M.
Desde el Consejo Nacional de Rectores (CONARE), instancia donde participan las cinco universidades públicas de Costa Rica, se gesta la iniciativa “Costa Rica aprende con la U pública”, la cual consiste en capacitar a la población nacional, de manera virtual y gratuita en distintas áreas de conocimiento. El presente artículo le permitirá conocer más sobre esta iniciativa, sus antecedentes, características y los resultados obtenidos en las ediciones realizadas.
Greenhouse gas emissions of African Stargrass-based dairy systems under organic or inorganic fertilization regimes
(2026-06-12) Solano López, Marvin Jaroht; Rojas Jiménez, Cristofer; Pezo, Danilo; Quiroz, Roberto A.; Chinchilla Soto, Isabel Cristina; Villalobos Villalobos, Luis Alonso
Background: Properly managed livestock operations play a significant role in reducing greenhouse gas emissions in agriculture. We assessed the effects of applying organic and inorganic fertilizers to African Stargrass pastures on greenhouse gas emissions.
Methods: The study was conducted at the Dairy Research Station of the University of Costa Rica (May–November 2019 and 2021). Six fertilization treatments were evaluated under a randomized complete block design. Greenhouse gases included methane (CH4) and carbon dioxide (CO2) fluxesmeasured at ground level using static chambers, nitrous oxide (N2O) emissions calculated using IPCC factors, and simulated enteric methane emissions usingthe LIFE-SIM model, based on forage biomass and nutritive value.
Results: CO2 emissions were numerically similar(p>0.05),with greater values in sulfur-coated urea (15,114kg ha−1) and lower in Azospirillum (13,799kg ha−1).Soil CH4 was significantly greater (p < 0.05) in ammonium nitrate (3.30kgha−1) with respect to sulfur-coated urea (1.37kg ha−1). Emission intensity wasnumerically greater in slurry (2.58kg CO2eq kg−1 DM), and lower values insulfur-coated urea (1.56kg CO2eq kg−1 DM). Conclusions: Although some significant differences were found for soilemissions, both CH4 and N2O were a small fraction of the emissions when totalized as CO2eq. The type of fertilizer applied to African Stargrass pastures influenced the emission intensity as a result of their impact on grass productivity. This study depicted the impact ofsoil and enteric emissions inpastures, providingan integrated approach for mitigation strategies to tackle emissions undertropical conditions.