Browsing by Author "Meza, Rodrigo"
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- ItemArsenic in drinking water and breast cancer: a case-control study from a high exposure area in Northern Chile(Springer Science and Business Media B.V., 2025) Blanco, Estela; Acevedo, Johanna; Perez, Liliana; Herrera, Marian; Duran, Viviana; Barlaro, Teresa; Meza, Rodrigo; Roa, Juan Carlos; Parra, Roxana; Benitez, Hugo; Schwalb, Molly E.; Steinmaus, Craig; Ferreccio, CatterinaPurpose Exposure to arsenic in drinking water is a cause of lung, bladder, and skin cancer, however the relation between arsenic and breast cancer is unclear. Northern Chile had high levels of arsenic in drinking water (up to 900 mu g/l) between 1950 and 1970, facilitating the study of outcomes with long latency. We conducted a breast cancer case-control study in Northern Chile (2014-2018) and analyzed 505 incident breast cancer cases and 409 population-based female controls with data collected on lifetime exposure to arsenic and potential confounders. Methods We identified cases in collaboration with cancer committees, hospitals, and medical facilities in the study area. Controls were recruited from the Chile Voter Registry. Logistic regression was used to assess the relationship between arsenic exposure and breast cancer adjusting for education and age. We evaluated cumulative, lifetime average and highest single year exposure with tertiles and quartiles and population weighted controls based on age and region of residence. Results Exposure levels were high in both cases and controls, with median (interquartile range) values of: 52 (15-84) and 42 (10-106) mu g/L for average lifetime concentration, respectively. Adjusted odds ratios (OR) for tertile of cumulative exposure to arsenic concentrations in water (< 1.17, 1.17-5.16, and >= 5.17 mg) were 1.00, 0.85 [95% confidence interval (CI), 0.60-1.18], and 1.10 (0.79-1.55). Results were similar for lifetime average and single-highest year exposure metrics. Conclusion We did not find evidence of increased odds of higher arsenic exposure among incident breast cancer cases compared to female population controls.
- ItemDendritic Architecture Predicts in vivo Firing Pattern in Mouse Ventral Tegmental Area and Substantia Nigra Dopaminergic Neurons(2021) Montero, Trinidad; Gatica, Rafael Ignacio; Farassat, Navid; Meza, Rodrigo; Gonzalez-Cabrera, Cristian; Roeper, Jochen; Henny, PabloThe firing activity of ventral tegmental area (VTA) and substantia nigra pars compacta (SNc) dopaminergic (DA) neurons is an important factor in shaping DA release and its role in motivated behavior. Dendrites in DA neurons are the main postsynaptic compartment and, along with cell body and axon initial segment, contribute to action potential generation and firing pattern. In this study, the organization of the dendritic domain in individual VTA and SNc DA neurons of adult male mice, and their relationship to in vivo spontaneous firing, are described. In comparison with dorsal VTA DA neurons, ventrally located VTA neurons (as measured by cell body location) possess a shorter total dendritic length and simpler dendritic architecture, and exhibit the most irregular in vivo firing patterns among DA neurons. In contrast, for DA neurons in the SNc, the higher irregularity of firing was related to a smaller dendritic domain, as measured by convex hull volumes. However, firing properties were also related to the specific regional distribution of the dendritic tree. Thus, VTA DA neurons with a larger extension of their dendritic tree within the parabrachial pigmented (PBP) nucleus fired more regularly compared with those with relatively more dendrites extending outside the PBP. For DA neurons in the SNc, enhanced firing irregularity was associated with a smaller proportion of dendrites penetrating the substantia nigra pars reticulata. These results suggest that differences in dendritic morphology contribute to the in vivo firing properties of individual DA neurons, and that the existence of region-specific synaptic connectivity rules that shape firing diversity.
- ItemKnockout or Knock-in? A Truncated D2 Receptor Protein Is Expressed in the Brain of Functional D2 Receptor Knockout Mice(2021) Sanchez, Natalia; Olivares-Costa, Montserrat; Gonzalez, Marcela P.; Munita, Roberto; Escobar, Angelica P.; Meza, Rodrigo; Herrera-Rojas, Mauricio; Albornoz, Jessica; Merello, Gianluca; Andres, Maria E.Null mice for the dopamine D2 receptor (D2R) have been instrumental in understanding the function of this protein. For our research, we obtained the functional D2R knockout mouse strain described initially in 1997. Surprisingly, our biochemical characterization showed that this mouse strain is not a true knockout. We determined by sequence analysis of the rapid 3 ' amplification of cDNA ends that functional D2R knockout mice express transcripts that lack only the eighth exon. Furthermore, immunofluorescence assays showed a D2R-like protein in the brain of functional D2R knockout mice. We verified by immunofluorescence that the recombinant truncated D2R is expressed in HEK293T cells, showing intracellular localization, colocalizing in the Golgi apparatus and the endoplasmic reticulum, but with less presence in the Golgi apparatus compared to the native D2R. As previously reported, functional D2R knockout mice are hypoactive and insensitive to the D2R agonist quinpirole. Concordantly, microdialysis studies confirmed that functional D2R knockout mice have lower extracellular dopamine levels in the striatum than the native mice. In conclusion, functional D2R knockout mice express transcripts that lead to a truncated D2R protein lacking from the sixth transmembrane domain to the C-terminus. We share these findings to avoid future confusion and the community considers this mouse strain in D2R traffic and protein-protein interaction studies.
- Item¿Son efectivos los cannabinoides en la esclerosis múltiple?(2017) Meza, Rodrigo; Peña, Javier; García, Karen; Corsi, Oscar; Rada G., Gabriel
- Item¿Son efectivos los corticoides en la necrólisis epidérmica tóxica y el síndrome de Stevens-Johnson?(2017) Meza, Rodrigo; Rada G., Gabriel; Varas Arancibia, Pablo Andrés