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1.
Nature ; 580(7805): 628-635, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32350476

RESUMO

Megathrust earthquakes are responsible for some of the most devastating natural disasters1. To better understand the physical mechanisms of earthquake generation, subduction zones worldwide are continuously monitored with geophysical instrumentation. One key strategy is to install stations that record signals from Global Navigation Satellite Systems2,3 (GNSS), enabling us to track the non-steady surface motion of the subducting and overriding plates before, during and after the largest events4-6. Here we use a recently developed trajectory modelling approach7 that is designed to isolate secular tectonic motions from the daily GNSS time series to show that the 2010 Maule, Chile (moment magnitude 8.8) and 2011 Tohoku-oki, Japan (moment magnitude 9.0) earthquakes were preceded by reversals of 4-8 millimetres in surface displacement that lasted several months and spanned thousands of kilometres. Modelling of the surface displacement reversal that occurred before the Tohoku-oki earthquake suggests an initial slow slip followed by a sudden pulldown of the Philippine Sea slab so rapid that it caused a viscoelastic rebound across the whole of Japan. Therefore, to understand better when large earthquakes are imminent, we must consider not only the evolution of plate interface frictional processes but also the dynamic boundary conditions from deeper subduction processes, such as sudden densification of metastable slab.

2.
Environ Sci Technol ; 54(23): 15180-15190, 2020 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-33185105

RESUMO

Microbial communities occurring in reference materials for artificial barriers (e.g., bentonites) in future deep geological repositories of radioactive waste can influence the migration behavior of radionuclides such as curium (CmIII). This study investigates the molecular interactions between CmIII and its inactive analogue europium (EuIII) with the indigenous bentonite bacterium Stenotrophomonas bentonitica at environmentally relevant concentrations. Potentiometric studies showed a remarkably high concentration of phosphates at the bacterial cell wall compared to other bacteria, revealing the great potential of S. bentonitica for metal binding. Infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS) confirmed the role of phosphates and carboxylate groups from the cell envelope in the bioassociation of EuIII. Additionally, time-resolved laser-induced fluorescence spectroscopy (TRLFS) identified phosphoryl and carboxyl groups from bacterial envelopes, among other released complexing agents, to be involved in the EuIII and CmIII coordination. The ability of this bacterium to form a biofilm at the surface of bentonites allows them to immobilize trivalent lanthanide and actinides in the environment.


Assuntos
Resíduos Radioativos , Cúrio , Európio , Stenotrophomonas
3.
Nature ; 512(7514): 299-302, 2014 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-25119049

RESUMO

On 1 April 2014, Northern Chile was struck by a magnitude 8.1 earthquake following a protracted series of foreshocks. The Integrated Plate Boundary Observatory Chile monitored the entire sequence of events, providing unprecedented resolution of the build-up to the main event and its rupture evolution. Here we show that the Iquique earthquake broke a central fraction of the so-called northern Chile seismic gap, the last major segment of the South American plate boundary that had not ruptured in the past century. Since July 2013 three seismic clusters, each lasting a few weeks, hit this part of the plate boundary with earthquakes of increasing peak magnitudes. Starting with the second cluster, geodetic observations show surface displacements that can be associated with slip on the plate interface. These seismic clusters and their slip transients occupied a part of the plate interface that was transitional between a fully locked and a creeping portion. Leading up to this earthquake, the b value of the foreshocks gradually decreased during the years before the earthquake, reversing its trend a few days before the Iquique earthquake. The mainshock finally nucleated at the northern end of the foreshock area, which skirted a locked patch, and ruptured mainly downdip towards higher locking. Peak slip was attained immediately downdip of the foreshock region and at the margin of the locked patch. We conclude that gradual weakening of the central part of the seismic gap accentuated by the foreshock activity in a zone of intermediate seismic coupling was instrumental in causing final failure, distinguishing the Iquique earthquake from most great earthquakes. Finally, only one-third of the gap was broken and the remaining locked segments now pose a significant, increased seismic hazard with the potential to host an earthquake with a magnitude of >8.5.

5.
Nature ; 467(7312): 198-202, 2010 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-20829792

RESUMO

The magnitude-8.8 Maule (Chile) earthquake of 27 February 2010 ruptured a segment of the Andean subduction zone megathrust that has been suspected to be of high seismic potential. It is the largest earthquake to rupture a mature seismic gap in a subduction zone that has been monitored with a dense space-geodetic network before the event. This provides an image of the pre-seismically locked state of the plate interface of unprecedentedly high resolution, allowing for an assessment of the spatial correlation of interseismic locking with coseismic slip. Pre-seismic locking might be used to anticipate future ruptures in many seismic gaps, given the fundamental assumption that locking and slip are similar. This hypothesis, however, could not be tested without the occurrence of the first gap-filling earthquake. Here we show evidence that the 2010 Maule earthquake slip distribution correlates closely with the patchwork of interseismic locking distribution as derived by inversion of global positioning system (GPS) observations during the previous decade. The earthquake nucleated in a region of high locking gradient and released most of the stresses accumulated in the area since the last major event in 1835. Two regions of high seismic slip (asperities) appeared to be nearly fully locked before the earthquake. Between these asperities, the rupture bridged a zone that was creeping interseismically with consistently low coseismic slip. The rupture stopped in areas that were highly locked before the earthquake but where pre-stress had been significantly reduced by overlapping twentieth-century earthquakes. Our work suggests that coseismic slip heterogeneity at the scale of single asperities should indicate the seismic potential of future great earthquakes, which thus might be anticipated by geodetic observations.

6.
Psychiatr Serv ; : appips20230399, 2024 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-38477835

RESUMO

The use of electronic devices and social media is becoming a ubiquitous part of most people's lives. Although researchers are exploring the sequelae of such use, little attention has been given to the importance of digital media use in routine psychiatric assessments of patients. The nature of technology use is relevant to understanding a patient's lifestyle and activities, the same way that it is important to evaluate the patient's occupation, functioning, and general activities. The authors propose a framework for psychiatric inquiry into digital media use, emphasizing that such inquiry should focus on quality of use, including emotional and behavioral consequences, rather than simply the amount of use.

7.
Sci Total Environ ; 915: 170149, 2024 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-38242445

RESUMO

Deep Geological Repositories (DGRs) consist of radioactive waste contained in corrosion-resistant canisters, surrounded by compacted bentonite clay, and buried few hundred meters in a stable geological formation. The effects of bentonite microbial communities on the long-term stability of the repository should be assessed. This study explores the impact of harsh conditions (60 °C, highly-compacted bentonite, low water activity), and acetate:lactate:sulfate addition, on the evolution of microbial communities, and their effect on the bentonite mineralogy, and corrosion of copper material under anoxic conditions. No bentonite illitization was observed in the treatments, confirming its mineralogical stability as an effective barrier for future DGR. Anoxic incubation at 60 °C reduced the microbial diversity, with Pseudomonas as the dominant genus. Culture-dependent methods showed survival and viability at 60 °C of moderate-thermophilic aerobic bacterial isolates (e.g., Aeribacillus). Despite the low presence of sulfate-reducing bacteria in the bentonite blocks, we proved their survival at 30 °C but not at 60 °C. Copper disk's surface remained visually unaltered. However, in the acetate:lactate:sulfate-treated samples, sulfide/sulfate signals were detected, along with microbial-related compounds. These findings offer new insights into the impact of high temperatures (60 °C) on the biogeochemical processes at the compacted bentonite/Cu canister interface post-repository closure.


Assuntos
Bentonita , Resíduos Radioativos , Bentonita/química , Resíduos Radioativos/análise , Cobre , Corrosão , Temperatura , Sulfatos , Lactatos , Acetatos
8.
J Hazard Mater ; 476: 135044, 2024 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-38943881

RESUMO

Deep geological repositories (DGRs) stand out as one of the optimal options for managing high-level radioactive waste (HLW) such as uranium (U) in the near future. Here, we provide novel insights into microbial behavior in the DGR bentonite barrier, addressing potential worst-case scenarios such as waste leakage (e.g., U) and groundwater infiltration of electron rich donors in the bentonite. After a three-year anaerobic incubation, Illumina sequencing results revealed a bacterial diversity dominated by anaerobic and spore-forming microorganisms mainly from the phylum Firmicutes. Highly U tolerant and viable bacterial isolates from the genera Peribacillus, Bacillus, and some SRB such as Desulfovibrio and Desulfosporosinus, were enriched from U-amended bentonite. The results obtained by XPS and XRD showed that U was present as U(VI) and as U(IV) species. Regarding U(VI), we have identified biogenic U(VI) phosphates, U(UO2)·(PO4)2, located in the inner part of the bacterial cell membranes in addition to U(VI)-adsorbed to clays such as montmorillonite. Biogenic U(IV) species as uraninite may be produced as result of bacterial enzymatic U(VI) reduction. These findings suggest that under electron donor-rich water-saturation conditions, bentonite microbial community can control U speciation, immobilizing it, and thus enhancing future DGR safety if container rupture and waste leakage occurs.

9.
Microorganisms ; 12(5)2024 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-38792854

RESUMO

Currently, the production of radioactive waste from nuclear industries is increasing, leading to the development of reliable containment strategies. The deep geological repository (DGR) concept has emerged as a suitable storage solution, involving the underground emplacement of nuclear waste within stable geological formations. Bentonite clay, known for its exceptional properties, serves as a critical artificial barrier in the DGR system. Recent studies have suggested the stability of bentonite within DGR relevant conditions, indicating its potential to enhance the long-term safety performance of the repository. On the other hand, due to its high resistance to corrosion, copper is one of the most studied reference materials for canisters. This review provides a comprehensive perspective on the influence of nuclear waste conditions on the characteristics and properties of DGR engineered barriers. This paper outlines how evolving physico-chemical parameters (e.g., temperature, radiation) in a nuclear repository may impact these barriers over the lifespan of a repository and emphasizes the significance of understanding the impact of microbial processes, especially in the event of radionuclide leakage (e.g., U, Se) or canister corrosion. Therefore, this review aims to address the long-term safety of future DGRs, which is critical given the complexity of such future systems.

10.
Environ Pollut ; 358: 124491, 2024 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-38964646

RESUMO

The deep geological repository (DGR) concept consists of storing radioactive waste in metal canisters, surrounded by compacted bentonite, and placed deeply into a geological formation. Here, bentonite slurry microcosms with copper canisters, inoculated with bacterial consortium and amended with acetate, lactate and sulfate were set up to investigate their geochemical evolution over a year under anoxic conditions. The impact of microbial communities on the corrosion of the copper canisters in an early-stage (45 days) was also assessed. The amended bacterial consortium and electron donors/acceptor accelerated the microbial activity, while the heat-shocked process had a retarding effect. The microbial communities partially oxidize lactate to acetate, which is subsequently consumed when the lactate is depleted. Early-stage microbial communities showed that the bacterial consortium reduced microbial diversity with Pseudomonas and Stenotrophomonas dominating the community. However, sulfate-reducing bacteria such as Desulfocurvibacter, Anaerosolibacter, and Desulfosporosinus were enriched coupling oxidation of lactate/acetate with reduction of sulfates. The generated biogenic sulfides, which could mediate the conversion of copper oxides (possibly formed by trapped oxygen molecules on the bentonite or driven by the reduction of H2O) to copper sulfide (Cu2S), were identified by X-ray photoelectron spectroscopy (XPS). Overall, these findings shed light on the ideal geochemical conditions that would affect the stability of DGR barriers, emphasizing the impact of the SRB on the corrosion of the metal canisters, the gas generation, and the interaction with components of the bentonite.

11.
Sci Rep ; 13(1): 19511, 2023 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-37945656

RESUMO

Large subduction earthquakes induce complex postseismic deformation, primarily driven by afterslip and viscoelastic relaxation, in addition to interplate relocking processes. However, these signals are intricately intertwined, posing challenges in determining the timing and nature of relocking. Here, we use six years of continuous GNSS measurements (2015-2021) to study the spatiotemporal evolution of afterslip, seismicity and locking after the 2015 Illapel earthquake ([Formula: see text] 8.3). Afterslip is inverted from postseismic displacements corrected for nonlinear viscoelastic relaxation modeled using a power-law rheology, and the distribution of locking is obtained from the linear trend of GNSS stations. Our results show that afterslip is mainly concentrated in two zones surrounding the region of largest coseismic slip. The accumulated afterslip (corresponding to [Formula: see text] 7.8) exceeds 1.5 m, with aftershocks mainly occurring at the boundaries of the afterslip patches. Our results reveal that the region experiencing the largest coseismic slip undergoes rapid relocking, exhibiting the behavior of a persistent velocity weakening asperity, with no observed aftershocks or afterslip within this region during the observed period. The rapid relocking of this asperity may explain the almost regular recurrence time of earthquakes in this region, as similar events occurred in 1880 and 1943.

12.
Sci Rep ; 13(1): 20109, 2023 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-37978308

RESUMO

The quantity and accuracy of satellite-geodetic measurements have increased over time, revolutionizing the monitoring of tectonic processes. Global Navigation Satellite System (GNSS) and satellite radar signals provide observations beyond ground deformation, including how earthquake and tsunami processes affect variations in the ionosphere. Here, we study the Hunga Tonga Hunga Ha'apai (HTHH) volcanic eruption 2022 and its associated tsunami propagation with the analysis GNSS derived Total Electron Content (TEC), Synthetic Aperture Radar (SAR) Sentinel-1 data, complemented with tide gauge observations. We utilize GNSS sites data within a ~ 5000 km radius from the volcanic eruption for estimating the ionospheric perturbation as Vertical TEC. We give evidence on the detection of acoustic gravity, internal gravity, and atmospheric Lamb waves signatures in the TEC perturbation. In particular, the internal gravity waves that concentrated in the southwest of Tonga, directly correlates with the observed tsunami propagation direction as accounted by the tide gauge measurements. However, the acoustic gravity wave signature in the TEC is dominant in the north direction suggesting a surface deformation, which could be verified using Sentinel-1A SAR amplitude data. The analysis presented herein shows that within 5 h of the volcanic eruption, the central part of the HTHH island landscape disappeared with the biggest explosion. The unprecedented detail resolved by integrating satellite data yields previously unknown details of the deformation of the 2022 HTHH volcano eruption.

13.
Rev Med Inst Mex Seguro Soc ; 61(Suppl 2): S263-S268, 2023 Sep 18.
Artigo em Espanhol | MEDLINE | ID: mdl-38016122

RESUMO

Background: Juvenile nasoangiofibroma (JNA) is a rare, highly vascular, locally aggressive benign tumor which affects male adolescents. It accounts for 0.05-0.5% of head and neck tumors with recurrence rates of 6-50%. The internal maxillary artery is the main source of JNA. Objective: To evaluate the relationship between vascular supply as a factor associated with JNA recurrence. Material and methods: An cohort study was performed in patients diagnosed with NAJ. We collected demographic data, vascular contribution by angiography and tomography results to classify them according to their stage (Radkowski classification), and if they received adjuvant radiotherapy. Post-surgical CT scans were requested to evaluate recurrence and if any of the variables were related to this. Results: A sample of 14 male patients who met the inclusion criteria was collected. The mean age was 14.71 ± 4.08 years. According to Radkowski classification, stage IA, IIA and IIC were reported in 14.3%, IIB and IIB in 7.1% and IIIA in 42.9%. 42.9% had recurrence and out of these, 66.7% had irrigation of the right carotid system and the same percentage of patients received radiotherapy as adjuvant treatment. Conclusions: There is a tendency in tumor recurrence associated with vascular contribution from the right carotid system, as well as with patients who received radiotherapy.


Introducción: el nasoangiofibroma juvenil (NAJ) es un tumor benigno, raro, altamente vascular y localmente agresivo que afecta a adolescentes del sexo masculino. Representa de 0.05 a 0.5% de los tumores de cabeza y cuello con tasas de recurencia del 6-50%. La arteria maxilar interna se considera el principal aporte de los NAJ. Objetivo: evaluar la relación entre el aporte vascular como factor asociado con la recurrencia de NAJ. Material y métodos: se realizó un estudio de cohorte en pacientes con diagnóstico de NAJ. Se recabaron datos demográficos, el aporte vascular por resultados de angiografía y de tomografía para clasificarlos según su estadio (clasificación de Radkowski), y si recibieron radioterapia adyuvante. Se solicitaron tomografías postquirúrgicas para evaluar la recurrencia y si alguna de las variables tiene relación con esta. Resultados: se recolectó una muestra de 14 pacientes del sexo masculino que cumplieron con los criterios de inclusión. La edad promedio fue de 14.71 ± 4.08 años. Según la clasificación de Radkowski, se reportó un estadio IA, IIA y IIC en 14.3%, IIB y IIB en un 7.1% y IIIA en 42.9%. El 42.9% tuvo recurrencia y de estos, el 66.7% tenía irrigación del sistema carotídeo derecho y recibieron radioterapia como tratamiento adyuvante el mismo porcentaje de pacientes. Conclusiones: existe una tendencia en la recurrencia del tumor asociada al aporte vascular proveniente del sistema carotídeo derecho y también a los pacientes que recibieron radioterapia.


Assuntos
Angiofibroma , Neoplasias Nasofaríngeas , Adolescente , Humanos , Masculino , Criança , Estudos de Coortes , Neoplasias Nasofaríngeas/diagnóstico , Neoplasias Nasofaríngeas/patologia , Neoplasias Nasofaríngeas/cirurgia , Estadiamento de Neoplasias , Recidiva Local de Neoplasia/diagnóstico , Recidiva Local de Neoplasia/cirurgia , Angiofibroma/diagnóstico , Angiofibroma/patologia , Angiofibroma/cirurgia , Estudos Retrospectivos
14.
Rev Med Inst Mex Seguro Soc ; 61(Suppl 2): S309-S317, 2023 Sep 18.
Artigo em Espanhol | MEDLINE | ID: mdl-38016186

RESUMO

Background: Tracheotomy is a common technique; however, microbiological contamination of the surgical site can increase morbimortality. Up to 90% of patients present a positive culture of the airway. Among the most important related factors is the lack of tracheal cannula replacement and lower airway infections. It is convenient to identify microbiological contamination of surgical site in tracheal secretions samples and the specific microorganism associated. Objective: To determine the factors related to microbiological contamination of surgical site. Material and methods: A prospective cohort study which included patients undergoing tracheotomy was carried out. Tracheal secretion was sampled by direct swabbing for culture during surgery and from the surgical site 5 days after. Results: The initial report showed contamination of samples in 58.3%, and 5 days after in 80.6%, with an incidence of contamination of 22.3%. Initially the main agents identified were Pseudomonas aeruginosa in 13.9% of the cultures, Klebsiella pneumoniae in 11.1% and Enterobacter spp. in 11%. On day 5, the most common agents were Klebsiella pneumoniae in 25% of the cases, Acinetobacter baumannii in 11.1% and Pseudomonas aeruginosa in 11.1. Conclusions: The frequency of microbiological contamination is high. The main agents were Staphylococcus aureus, Klebsiella pneumoniae and Pseudomonas aeruginosa. No risk factors for the presence of post-tracheotomy contamination were identified.


Introducción: la traqueotomía es un procedimiento común; sin embargo, la contaminación microbiológica del sitio quirúrgico puede aumentar la morbimortalidad. Hasta el 90% de los pacientes presentan un cultivo positivo de la vía respiratoria. Como factores relacionados, resaltan la falta de recambio de cánulas traqueales y las infecciones de vías aéreas bajas. Es conveniente identificar la contaminación microbiológica de secreción traqueal del sitio quirúrgico y el microorganismo asociado. Objetivo: determinar los factores relacionados con la contaminación microbiológica del sitio quirúrgico. Material y métodos: se hizo un estudio de cohorte prospectiva que incluyó a pacientes sometidos a traqueotomía. Se tomó cultivo por hisopado directo de secreción traqueal durante la cirugía y del sitio quirúrgico 5 días después. Resultados: la muestra inicial mostró contaminación en 58.3% de los pacientes y a los 5 días postquirúrgicos en 80.6%, con incidencia de contaminación de 22.3%. Inicialmente se aisló Pseudomonas aeruginosa en 13.9% de los casos, Klebsiella pneumoniae en 11.1% y Enterobacter spp. en 11%. Al quinto día se aisló Klebsiella pneumoniae en 25% de los casos, Acinetobacter baumannii en 11.1% y Pseudomonas aeruginosa en 11.1%. Conclusiones: la frecuencia de contaminación microbiológica es alta y se encontraron principalmente Staphylococcus aureus, Klebsiella pneumoniae y Pseudomonas aeruginosa. No se identificaron factores de riesgo para la contaminación postquirúrgica.


Assuntos
Staphylococcus aureus , Traqueotomia , Humanos , Estudos Prospectivos , Antibacterianos , Pseudomonas aeruginosa
15.
J Hazard Mater ; 458: 131940, 2023 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-37390682

RESUMO

Deep Geological Repository (DGR) is the preferred option for the final disposal of high-level radioactive waste. Microorganisms could affect the safety of the DGR by altering the mineralogical properties of the compacted bentonite or inducing the corrosion of the metal canisters. In this work, the impact of physicochemical parameters (bentonite dry density, heat shock, electron donors/acceptors) on the microbial activity, stability of compacted bentonite and corrosion of copper (Cu) discs was investigated after one-year anoxic incubation at 30 ºC. No-illitization in the bentonite was detected confirming its structural stability over 1 year under the experimental conditions. The microbial diversity analysis based on 16 S rRNA gene Next Generation Sequencing showed slight changes between the treatments with an increase of aerobic bacteria belonging to Micrococcaceae and Nocardioides in heat-shock tyndallized bentonites. The survival of sulfate-reducing bacteria (the main source of Cu anoxic corrosion) was demonstrated by the most probable number method. The detection of CuxS precipitates on the surface of Cu metal in the bentonite/Cu metal samples amended with acetate/lactate and sulfate, indicated an early stage of Cu corrosion. Overall, the outputs of this study help to better understand the predominant biogeochemical processes at the bentonite/Cu canister interface upon DGR closure.


Assuntos
Microbiota , Resíduos Radioativos , Bentonita/química , Resíduos Radioativos/análise , Cobre/análise , Argila , Corrosão , Sulfatos/análise
16.
Front Microbiol ; 14: 1134078, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37007474

RESUMO

To date, the increasing production of radioactive waste due to the extensive use of nuclear power is becoming a global environmental concern for society. For this reason, many countries have been considering the use of deep geological repositories (DGRs) for the safe disposal of this waste in the near future. Several DGR designs have been chemically, physically, and geologically well characterized. However, less is known about the influence of microbial processes for the safety of these disposal systems. The existence of microorganisms in many materials selected for their use as barriers for DGRs, including clay, cementitious materials, or crystalline rocks (e.g., granites), has previously been reported. The role that microbial processes could play in the metal corrosion of canisters containing radioactive waste, the transformation of clay minerals, gas production, and the mobility of the radionuclides characteristic of such residues is well known. Among the radionuclides present in radioactive waste, selenium (Se), uranium (U), and curium (Cm) are of great interest. Se and Cm are common components of the spent nuclear fuel residues, mainly as 79Se isotope (half-life 3.27 × 105 years), 247Cm (half-life: 1.6 × 107 years) and 248Cm (half-life: 3.5 × 106 years) isotopes, respectively. This review presents an up-to-date overview about how microbes occurring in the surroundings of a DGR may influence their safety, with a particular focus on the radionuclide-microbial interactions. Consequently, this paper will provide an exhaustive understanding about the influence of microorganisms in the safety of planned radioactive waste repositories, which in turn might improve their implementation and efficiency.

17.
Biol Reprod ; 87(6): 150, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23077168

RESUMO

Mast cells (MC) occur normally in the testis with a species-specific distribution, yet their precise role remains unclear. Testicular MC express histidine decarboxylase (HDC), the unique enzyme responsible for histamine (HA) generation. Evidence to date supports a role for HA as a local regulator of steroidogenesis via functional H1 and H2 receptor subtypes (HRH1 and HRH2, respectively) present in Leydig cells. Given that HA is a well-known modulator of physiological and pathological proliferation in many different cell types, we aimed in the present study to evaluate whether HA might contribute to the regulation of Leydig cell number as well as to the control of androgen production. Herein, we demonstrate, to our knowledge for the first time, that MA-10 Leydig tumor cells, but not normal immature Leydig cells (ILC), exhibit a proliferative response upon stimulation with HA that involves HRH2 activation, transient elevation of cAMP levels, and increased extracellular signal-regulated kinase (ERK) phosphorylation. Our results also reveal that MA-10 cells show significantly heightened HDC expression compared to normal ILC or whole-testicular lysate and that inhibition of HDC activity decreases MA-10 cell proliferation, suggesting a possible correlation between autocrine overproduction of HA and abnormally increased proliferation in Leydig cells. The facts that germ cells are also both source and target of HA and that multiple testicular cells are susceptible to HA action underline the importance of the present study, which we hope will serve as a first step for further research into regulation of non-MC-related HDC expression within the testis and its significance for testicular function.


Assuntos
AMP Cíclico/metabolismo , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Histamina/metabolismo , Tumor de Células de Leydig/metabolismo , Células Intersticiais do Testículo/metabolismo , Receptores Histamínicos H2/metabolismo , Sistemas do Segundo Mensageiro , Animais , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , AMP Cíclico/antagonistas & inibidores , Inibidores Enzimáticos/farmacologia , MAP Quinases Reguladas por Sinal Extracelular/antagonistas & inibidores , Agonistas dos Receptores Histamínicos/metabolismo , Agonistas dos Receptores Histamínicos/farmacologia , Histidina Descarboxilase/antagonistas & inibidores , Histidina Descarboxilase/biossíntese , Histidina Descarboxilase/metabolismo , Tumor de Células de Leydig/tratamento farmacológico , Tumor de Células de Leydig/enzimologia , Células Intersticiais do Testículo/citologia , Células Intersticiais do Testículo/efeitos dos fármacos , Células Intersticiais do Testículo/enzimologia , Masculino , Camundongos , Proteínas de Neoplasias/antagonistas & inibidores , Proteínas de Neoplasias/biossíntese , Proteínas de Neoplasias/metabolismo , Fosforilação/efeitos dos fármacos , Processamento de Proteína Pós-Traducional/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Receptores Histamínicos H2/química , Sistemas do Segundo Mensageiro/efeitos dos fármacos , Células-Tronco/citologia , Células-Tronco/efeitos dos fármacos , Células-Tronco/metabolismo
18.
Sci Rep ; 12(1): 21710, 2022 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-36522366

RESUMO

The b-value can be used to characterize the seismic activity for a given earthquake catalog and provide information on the stress level accumulated at active faults. Here we develop an algorithm to objectively estimate variations of b-value along one arbitrary dimension. To this end, we employ a Bayesian transdimensional approach where the seismic domains will be self-defined according to information in the seismic catalog. This makes it unnecessary to prescribe the location and extent of domains, as it is commonly done. We first show the algorithm's robustness by performing regressions from synthetic catalogs, recovering the target models with great accuracy. We also apply the algorithm to a microseismicity catalog for the Central Chile region. This segment is considered a seismic gap where the last major earthquake with shallow slip was in 1730. Our results illuminate the downdip limit of the seismogenic zone and the transition to intraslab seismicity. In the along-strike direction, low b-value coincides with the extent of locked asperities, suggesting a high-stress loading at the Central Chile seismic gap. Our results indicate the reliability of the Bayesian transdimensional method for capturing robust b-value variations, allowing us to characterize the mechanical behavior on the plate interface of subduction zones.

19.
Lancet Reg Health Am ; 10: 100255, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36777691

RESUMO

Indigenous Peoples suffer environmental violence related to pesticide exposure, including imported pesticides that are banned in the exporting countries (including the U.S.) due to their known detrimental health impacts and used in or near their traditional territories. The Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) is a U.S. statue that allows "pesticides that are not approved - or registered - for use in the U.S." to be manufactured in the U.S. and exported elsewhere. The UN Rotterdam Convention also allows the global exportation of "banned pesticides." The ongoing exportation of banned pesticides leads to disproportionately high rates of morbidity and mortality, most notably in Indigenous women and children. In this paper, we present evidence describing the documented harms of banned pesticides with a focus on the Yaqui Nation in Sonora, Mexico, give background on the problematic laws allowing these harms, and highlight concrete solutions.

20.
J Endocrinol ; 255(3): 103-116, 2022 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-36069766

RESUMO

Recent reports indicate an increase in Leydig cell tumor (LCT) incidence. Radical orchiectomy is the standard therapy in children and adults, although it entails physical and psychosocial side effects. Testis-sparing surgery can be a consideration for benign LCT of 2.5 cm or less in size. Malignant LCTs respond poorly to conventional chemotherapy, so new treatment modalities are needed. In this study, we observed increased histidine decarboxylase expression and pro-angiogenic potential in LCT surgically resected from pediatric patients (fetal to pubertal) vs control samples from patients without endocrine or metabolic disorders which were collected at necropsy. We, therefore, evaluated for the first time the antitumor efficacy of two histidine decarboxylase inhibitors (α-methyl-dl-histidine dihydrochloride (α-MHD) and epigallocatechin gallate (EGCG)), alone and combined with carboplatin, in two preclinical models of LCT. MA-10 and R2C Leydig tumor cells, representing two different LCT subtypes, were used to generate syngeneic and xenograft mouse LCT models, respectively. In the syngeneic model, monotherapy with α-MHD effectively reduced tumor growth and angiogenesis. In the xenografts, which showed co-expression of histidine decarboxylase and CYP19, the combination of EGCG plus carboplatin was the most effective therapy, leading to LCT growth arrest and undetectable levels of plasmatic estradiol. Testicular and body weights remained unaltered. On the basis of this study, histidine decarboxylase may emerge as a novel pharmacological target for LCT treatment.


Assuntos
Tumor de Células de Leydig , Neoplasias Testiculares , Animais , Aromatase , Carboplatina , Estradiol , Histidina , Histidina Descarboxilase/genética , Humanos , Tumor de Células de Leydig/metabolismo , Tumor de Células de Leydig/patologia , Tumor de Células de Leydig/cirurgia , Masculino , Camundongos , Neoplasias Testiculares/metabolismo , Neoplasias Testiculares/patologia , Neoplasias Testiculares/cirurgia
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