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1.
J Environ Radioact ; 273: 107391, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38316100

RESUMEN

The consequences of mass radiological events, particularly those involving the activation of a radiological dispersion device (RDD), have been extensively studied by scientific groups. However, the critical initial period of such an event, usually spanning the first 100 h, can be characterized by a scarcity of information, potentially leading to delays in mitigating strategies. In response, a research group utilized computer simulations to generate solid, conservative analytical details that can aid decision-making and guide the prioritization of initial care based on variables such as age, sex, location, and local atmospheric stability conditions. The study estimates the Lost Life Expectancy (LLE) and provides relevant information to increase support for decision-making and allow evaluation of data closer to the lay public. The research team behind the study has been granted funding by the Brazilian National Council for Scientific and Technological Development (CNPq), and further simulations will be conducted utilizing codes that implement numerical models, specifically in atmospheric data forecasting. The methodology used to evaluate the LLE can be applied to any location, provided that the relevant variables are updated accordingly. Overall, this study offers critical insights into the impact of mass radiological events and enhances simulations' predictive capacity and precision.


Asunto(s)
Monitoreo de Radiación , Esperanza de Vida , Simulación por Computador , Brasil
2.
Health Phys ; 126(4): 188-195, 2024 Apr 01.
Artículo en Portugués, Inglés | MEDLINE | ID: mdl-38252033

RESUMEN

ABSTRACT: This study evaluates the influence of the method used to calculate the effective atomic number (Z eff ) on the estimate of secondary radiation yielded under kilovoltage x-ray beams by metal alloys with a wide range of biomedical applications. Two methods for calculating Z eff (referred to here as M 1 and M 2 ) are considered, and six metallic alloys are investigated: Ti-6Al-4 V, Co-Cr-Mo, Ni-Cr-Ti, Ni-Cr, Co-Cr-Mo-W, and Ag 3 Sn-Hg (amalgam). The results indicate significant differences in the estimates of fluorescence yield depending on the method used to estimate Z eff for each metallic alloy. Both the choice of the calculation method for Z eff and the energy ranges of the incident radiation are essential factors affecting the behavior of alloys in terms of fluorescence production. Our results may guide the selection of the best material for a biomedical application. The metallic alloys simulated here show equivalences and discrepancies that depend on the method used to estimate Z eff and the energy range of the incident photons. This finding allows for the creation of combinations of alloys and methods for calculating Z eff and the photon energy to maximize safety and minimize cost.


Asunto(s)
Aleaciones , Titanio , Fluorescencia , Níquel , Ensayo de Materiales
3.
Nano Lett ; 24(10): 3021-3027, 2024 Mar 13.
Artículo en Inglés | MEDLINE | ID: mdl-38252876

RESUMEN

The effects on the lattice structure and electronic properties of different polymorphs of silver halide, AgX (X = Cl, Br, and I), induced by laser irradiation (LI) and electron irradiation (EI) are investigated using a first-principles approach, based on the electronic temperature (Te) within a two-temperature model (TTM) and by increasing the total number of electrons (Ne), respectively. Ab initio molecular dynamics (AIMD) simulations provide a clear visualization of how Te and Ne induce a structural and electronic transformation process during LI/EI. Our results reveal the diffusion processes of Ag and X ions, the amorphization of the AgX lattices, and a straightforward interpretation of the time evolution for the formation of Ag and X nanoclusters under high values of Te and Ne. Overall, the present work provides fine details of the underlying mechanism of LI/EI and promises to be a powerful toolbox for further cross-scale modeling of other semiconductors.

4.
Radiat Prot Dosimetry ; 200(2): 206-213, 2024 Feb 16.
Artículo en Inglés | MEDLINE | ID: mdl-37968997

RESUMEN

This study considers a deliberate hypothetical release of radioactive material over an inhabited urban zone. The event is initiated by the activation of a radiological dispersion device. The main threat is the deposition of radioactive material onto the soil's surface. The radiation represents the threat-defining risks, which depend on the main variables, i.e. soil surface roughness, sex, age of the exposed individuals and the moment of the release (day or nighttime). This study aims to evaluate the effect of soil surface roughness on the radiological risk. The simulation was performed by an analytical method using the HotSpot Health Physics code within the first 100 h. The results found relevant elements that allow for differentiating consequences as a function of the time of release (whether daytime or nighttime), thus allowing decision-makers to be supported with a little more detail about the situation, although in a critical initial phase.


Asunto(s)
Monitoreo de Radiación , Humanos , Monitoreo de Radiación/métodos , Radiografía , Simulación por Computador , Física Sanitaria , Suelo
5.
SAGE Open Med Case Rep ; 11: 2050313X231180725, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37359283

RESUMEN

Herpesvirus reactivates from a latent infection in older adults and critically ill and immunocompromised individuals. Herpes zoster ophthalmicus (HZO) is a latent infection that affects the fifth cranial nerve. It is an infrequent cause of increased intraocular pressure. We present the case of a 50-year-old man with a reactivation of latent varicella-zoster virus infection involving the ophthalmic branch of the fifth cranial nerve. The patient was initially managed as an outpatient with an antiviral, but his clinical evolution worsened and required urgent surgical decompression. Lateral canthotomy was performed with cantholysis of the inferior crus of the lateral canthal tendon. Only partial decompression was achieved, so cantholysis of the upper crus was performed with significant tissue tension release. The patient evolved well and was discharged after 6 days without symptoms for outpatient management.

6.
Syst Parasitol ; 100(5): 531-542, 2023 10.
Artículo en Inglés | MEDLINE | ID: mdl-37340144

RESUMEN

During a research of digeneans (Platyhelminthes: Trematoda) infecting leaf-nosed bats (Chiroptera: Phyllostomidae) from the Kawsay Biological Station in Madre de Dios, southeastern Peru, four new species were described based on light and scanning electron microscopy (SEM): Anenterotrema paramegacetabulum n. sp. from the seba's short-tailed bat Carollia perspicillata Linnaeus, A. hastati n. sp., A. kawsayense n. sp., and A. peruense n. sp. from the greater spear-nosed bat Phyllostomus hastatus (Pallas). Anenterotrema paramegacetabulum n. sp. differs from all congeners by having a terminal oral sucker, a transversely elongated ventral sucker without clamp-shaped, and by having the testes located immediately posterior to ventral sucker. Anenterotrema hastati n. sp. is easily differentiated from the other congeneric species by having an almost clamp-shaped oral sucker, well-developed cirrus sac, a bilobulated seminal receptacle, and a group of well-developed unicellular glands located anterolateral to cirrus sac. Anenterotrema kawsayense n. sp. is characterized by possessing protuberances on the anterior margin of the oral sucker. Anenterotrema peruense n. sp. is mainly characterized by having the testes located principally anterior to ventral sucker and the cirrus sac located perpendicular to midline of the body. The present finding brings to 12, the number of known species of Anenterotrema. A key to the species of Anenterotrema Stunkard, 1938 is provided.


Asunto(s)
Quirópteros , Trematodos , Infecciones por Trematodos , Animales , Perú , Especificidad de la Especie
8.
Carbohydr Polym ; 304: 120505, 2023 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-36641171

RESUMEN

It is advantageous to understand the relationship between cellulose fiber morphology and the rheological behavior of its dispersions so that their application can be optimized. The goal of this study was to produce sugarcane bagasse-sourced cellulose dispersions with different numbers of high-pressure homogenization cycles. Microfluidization produced cellulose nanofibers (between 5 and 80 nm in diameter) with similar surface charge densities and crystallinities (measured on the resulting films). Oscillatory rheology showed that TEMPO-oxidized cellulose dispersions exhibited gel-like behavior. However, not only did the samples with more microfluidization cycles present a lower storage modulus, but the sample with 100 cycles completely lost the gel-like characteristic, presenting a viscous fluid rheological behavior. Thixotropy loop tests revealed the influence of nanofiber length on the dispersion's structure, as evidenced by the decrease in the hysteresis value along with fiber breakage. Therefore, our findings demonstrate that the rheological properties of the dispersion can be tuned according to the length of the nanofibers, allowing for targeted applications.


Asunto(s)
Celulosa Oxidada , Nanofibras , Saccharum , Celulosa/química , Nanofibras/química , Reología/métodos
9.
J Radiol Prot ; 42(3)2022 09 29.
Artículo en Inglés | MEDLINE | ID: mdl-36130586

RESUMEN

This study evaluates the risk assessment of a hypothetical scenario where an off-site radioactive release occurs at a nuclear power plant. By using the code Accident Reporting and Guiding Operational System (Prolog Development Center - PDC/ARGOS) a numerical simulation was performed to simulate exposure conditions in an atmospheric plume of contamination. Crews on a rescue mission traverse the plume through a pre-defined path to evaluate the risk from a hypothetical radiological exposure. Applying a sophisticated epidemiological assessment methodology, radiation doses and risks on the teams were evaluated. Core variables such as gender, age and radiation dose were considered in relation to specific morbidities. It was possible to propose a methodology capable of contributing to the reduction of risks to the personnel involved by connecting the results from the computer simulation and the epidemiological risk assessment.


Asunto(s)
Monitoreo de Radiación , Liberación de Radiactividad Peligrosa , Simulación por Computador , Plantas de Energía Nuclear , Dosis de Radiación , Monitoreo de Radiación/métodos , Medición de Riesgo
10.
Phys Rev Lett ; 129(4): 046101, 2022 Jul 22.
Artículo en Inglés | MEDLINE | ID: mdl-35939018

RESUMEN

Using a combination of in situ high-resolution transmission electron microscopy and density functional theory, we report the formation and rupture of ZrO_{2} atomic ionic wires. Near rupture, under tensile stress, the system favors the spontaneous formation of oxygen vacancies, a critical step in the formation of the monatomic bridge. In this length scale, vacancies provide ductilelike behavior, an unexpected mechanical behavior for ionic systems. Our results add an ionic compound to the very selective list of materials that can form monatomic wires and they contribute to the fundamental understanding of the mechanical properties of ceramic materials at the nanoscale.

11.
Phytopathology ; 112(10): 2224-2235, 2022 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-35596236

RESUMEN

Scab, caused by the plant-pathogenic fungus Venturia effusa, is a major disease of pecan in South America, resulting in loss of quantity and quality of nut yield. Characteristics of the populations of V. effusa in South America are unknown. We used microsatellites to describe the genetic diversity and population structure of V. effusa in South America, and determined the mating type status of the pathogen. The four hierarchically sampled orchard populations from Argentina (AR), Brazil (BRC and BRS), and Uruguay (UR) had moderate to high genotypic and gene diversity. There was evidence of population differentiation (Fst = 0.196) but the correlation between geographic distance and genetic distance was not statistically significant. Genetic differentiation was minimal between the UR, BRC, and BRS populations, and these populations were more clearly differentiated from the AR population. The MAT1-1 and MAT1-2 mating types occurred in all four orchards and their frequencies did not deviate from the 1:1 ratio expected under random mating; however, multilocus linkage equilibrium was rejected in three of the four populations. The population genetics of South American populations of V. effusa has many similarities to the population genetics of V. effusa previously described in the United States. Characterizing the populations genetics and reproductive systems of V. effusa are important to establish the evolutionary potential of the pathogen and, thus, its adaptability-and can provide a basis for informed approaches to utilizing available host resistance and determining phytosanitary needs.


Asunto(s)
Ascomicetos , Carya , Ascomicetos/genética , Brasil , Carya/genética , Carya/microbiología , Hongos del Género Venturia , Genes del Tipo Sexual de los Hongos/genética , Variación Genética , Genética de Población , Enfermedades de las Plantas/microbiología
12.
Nanomaterials (Basel) ; 12(10)2022 May 11.
Artículo en Inglés | MEDLINE | ID: mdl-35630858

RESUMEN

Hematite is considered a promising photoanode material for photoelectrochemical water splitting, and the literature has shown that the photoanode production process has an impact on the final efficiency of hydrogen generation. Among the methods used to process hematite photoanode, we can highlight the thin films from the colloidal deposition process of magnetic nanoparticles. This technique leads to the production of high-performance hematite photoanode. However, little is known about the influence of the magnetic field and heat treatment parameters on the final properties of hematite photoanodes. Here, we will evaluate those processing parameters in the morphology and photoelectrochemical properties of nanostructured hematite anodes. The analysis of thickness demonstrated a relationship between the magnetic field and nanoparticles concentration utilized to prepare the thin films, showing that the higher magnetic fields decrease the thickness. The Jabs results corroborate to influence the magnetic field since the use of a higher magnetic field decreases the deposited material amount, consequently decreasing the absorption of the thin films. The PEC measurements showed that at higher concentrations, the use of higher magnetic fields increases the JPH values, and lower magnetic fields cause a decrease in JPH when using the higher nanoparticle concentrations.

13.
Cir Cir ; 90(3): 406-409, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35636944

RESUMEN

Arterioenteric fistulas (AEFs) are a rare disease. They are a communication between a major artery and digestive tract. We present a patient who, after suffering a gunshot wound to the abdomen, underwent an exploratory laparotomy with damage control surgery, who later presented with hematemesis and melena. Studies were performed where an aneursyma of the right renal artery and gastrointestinal bleeding due to primary arterioenteric fistula were evidenced, which is successfully treated by angioembolization. Endovascular therapy for the treatment of AEF is a useful resource in patients with the previous abdominal surgeries that could make their management more difficult.


Las fístulas arterio-entéricas son un padecimiento infrecuente. Son una comunicación entre una arteria mayor y el tracto digestivo. Paciente masculino quien sufre una herida por arma de fuego en abdomen se le realiza una laparotomía exploradora con cirugía de control de daños, quien posteriormente presenta cuadro de hematemesis y melena. Se realizan estudios donde se evidencia un aneursima de la arteria renal derecha y sangrado de tubo digestivo por fístula arterioentérica primaria, la cual se trata por medio de angioembolización de manera exitosa. La terapia endovascular para el tratamiento de fístula arterio-enterica es un recurso útil en pacientes con cirugías abdominales previas que pudieran hacer más difícil el manejo.


Asunto(s)
Procedimientos Endovasculares , Fístula Intestinal , Heridas por Arma de Fuego , Procedimientos Endovasculares/efectos adversos , Hemorragia Gastrointestinal/etiología , Humanos , Fístula Intestinal/etiología , Fístula Intestinal/cirugía , Heridas por Arma de Fuego/complicaciones , Heridas por Arma de Fuego/cirugía
14.
Front Immunol ; 13: 784463, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35370994

RESUMEN

Visceral leishmaniasis (VL) is a vector-borne infectious disease that can be potentially fatal if left untreated. In Brazil, it is caused by Leishmania infantum parasites. Blood transcriptomics allows us to assess the molecular mechanisms involved in the immunopathological processes of several clinical conditions, namely, parasitic diseases. Here, we performed mRNA sequencing of peripheral blood from patients with visceral leishmaniasis during the active phase of the disease and six months after successful treatment, when the patients were considered clinically cured. To strengthen the study, the RNA-seq data analysis included two other non-diseased groups composed of healthy uninfected volunteers and asymptomatic individuals. We identified thousands of differentially expressed genes between VL patients and non-diseased groups. Overall, pathway analysis corroborated the importance of signaling involving interferons, chemokines, Toll-like receptors and the neutrophil response. Cellular deconvolution of gene expression profiles was able to discriminate cellular subtypes, highlighting the contribution of plasma cells and NK cells in the course of the disease. Beyond the biological processes involved in the immunopathology of VL revealed by the expression of protein coding genes (PCGs), we observed a significant participation of long noncoding RNAs (lncRNAs) in our blood transcriptome dataset. Genome-wide analysis of lncRNAs expression in VL has never been performed. lncRNAs have been considered key regulators of disease progression, mainly in cancers; however, their pattern regulation may also help to understand the complexity and heterogeneity of host immune responses elicited by L. infantum infections in humans. Among our findings, we identified lncRNAs such as IL21-AS1, MIR4435-2HG and LINC01501 and coexpressed lncRNA/mRNA pairs such as CA3-AS1/CA1, GASAL1/IFNG and LINC01127/IL1R1-IL1R2. Thus, for the first time, we present an integrated analysis of PCGs and lncRNAs by exploring the lncRNA-mRNA coexpression profile of VL to provide insights into the regulatory gene network involved in the development of this inflammatory and infectious disease.


Asunto(s)
Leishmania infantum , Leishmaniasis Visceral , Leishmaniasis , ARN Largo no Codificante , Humanos , Leishmania infantum/genética , Leishmaniasis Visceral/genética , ARN Largo no Codificante/genética , ARN Mensajero/genética , Transcriptoma
15.
Nanoscale ; 14(18): 6811-6821, 2022 May 16.
Artículo en Inglés | MEDLINE | ID: mdl-35388391

RESUMEN

Molybdenum disulfide (MoS2) is a very promising layered material for electrical, optical, and electrochemical applications because of its unique and outstanding properties. To unlock its full potential, among different preparation routes, electrochemistry has gain interest due to its simple, fast, scalable and simple instrumentation. However, obtaining large-area monolayer MoS2 that will enable the fabrication of novel electronic and electrochemical devices is still challenging. In this work, we reported a simple and fast electrochemical thinning process that results in ultra-large MoS2 down to monolayer on Au surfaces. The high affinity of MoS2 by Au surfaces enables the removal of bulk layers while preserving the first layer attached to the electrode. With a proper choice of the applied potential, more than 90% of the bulk regions can be removed from large-area MoS2 crystals, as confirmed by atomic force microscopy, photoluminescence, and Raman spectroscopy. We further address a set of contributions that are helpful to elucidate the features of MoS2, namely, the hyphenation of electrochemistry and optical microscopy for real-time observation of the thinning process that was revealed to occur from the edges to the center of the flake, an image treatment to estimate the thinning area and thinning rate, and the preparation of free-standing MoS2 layers by electrochemically thinning bulk flakes on microhole-structured Ni/Au meshes.

16.
Toxicol Ind Health ; 38(3): 176-181, 2022 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-35244457

RESUMEN

The application of nuclear technologies in a cargo and container inspection facility can increase the risk of accidents. Estimating the radiation dose in the controlled area generates critical information for elaborating routines aimed at establishing more effective safety procedures. For radiological protection purposes, mapping ambient dose equivalent H*(10) levels is crucial. The radiation source used was a fixed linear accelerator of 4.5 MeV. Five RadEye PRD-ER (Thermo Fisher Scientific) personal radiation monitors and five Geiger-Müller MRAD 111 (Ultra Radac) personal radiation monitors were used for the radiation measurements. The highest ambient equivalent dose rate and dose per scan were found with the Geiger-Müller monitors at values of 5.76E-01 mSv/h and 1.12E-03 mSv, respectively. The results showed that for public individuals, the number of scans at the point of highest dose rate value cannot exceed 893-unit operations. Additionally, the risks involved in the abnormal situation (increased H*(10)) were estimated by using a model to predict the development of solid cancer as a result of occupational radiological exposure. This procedure highlights the risks involved, hence providing initial support to the decision process.


Asunto(s)
Exposición Profesional , Monitoreo de Radiación , Protección Radiológica , Humanos , Exposición Profesional/análisis , Dosis de Radiación , Monitoreo de Radiación/métodos , Protección Radiológica/métodos
17.
Cir Cir ; 90(1): 29-33, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35120103

RESUMEN

INTRODUCTION: Biliary pathology is a common disorder during pregnancy and its complications can put the pregnancy at risk. MATERIAL AND METHODS: A retrospective study of laparoscopic cholecystectomies in pregnant women was carried out during the period from January 2017 to April 2020 at Hospital Universitario "Dr. José Eleuterio González". RESULTS: A total of 46 cases were obtained, only 3 patients had product loss, 1 immediately after surgery, second at 8 weeks' gestation, and the third due to complications of gestational hypertension. CONCLUSION: Pancreatic-biliary cases during pregnancy are high risk for gestation, so it is preferable to perform laparoscopic cholecystectomy in selected cases were arising complications.


INTRODUCCIÓN: La patología biliar es un trastorno muy común durante el embarazo y sus complicaciones pueden poner en riesgo el embarazo. MATERIAL Y MÉTODOS: Se realizó un estudio retrospectivo de las colecistectomías laparoscópicas en embarazadas durante el período de enero del 2017 a abril del 2020 en el Hospital Universitario "Dr. José Eleuterio González". RESULTADOS: Se obtuvieron 46 casos en total, de los cuales solo 3 pacientes se obtuvo pérdida del producto, 1 inmediatamente posterior a la cirugía, la segunda a las 8 semanas de gestación y la tercera por complicaciones de la hipertensión gestacional. CONCLUSIONES: Los cuadros pancreato-biliares en el embarazo son de alto riesgo para la gestación, por lo que es preferible realizar colecistectomía laparoscópica en cuadros seleccionados en vías de complicación.


Asunto(s)
Colecistectomía Laparoscópica , Complicaciones del Embarazo , Femenino , Edad Gestacional , Humanos , Embarazo , Complicaciones del Embarazo/epidemiología , Complicaciones del Embarazo/cirugía , Estudios Retrospectivos
18.
Ann Neurol ; 91(5): 652-669, 2022 05.
Artículo en Inglés | MEDLINE | ID: mdl-35226368

RESUMEN

OBJECTIVE: Astrocytes play a significant role in the pathology of multiple sclerosis (MS). Nevertheless, for ethical reasons, most studies in these cells were performed using the Experimental Autoimmune Encephalomyelitis model. As there are significant differences between human and mouse cells, we aimed here to better characterize astrocytes from patients with MS (PwMS), focusing mainly on mitochondrial function and cell metabolism. METHODS: We obtained and characterized induced pluripotent stem cell (iPSC)-derived astrocytes from three PwMS and three unaffected controls, and performed electron microscopy, flow cytometry, cytokine and glutamate measurements, gene expression, in situ respiration, and metabolomics. We validated our findings using a single-nuclei RNA sequencing dataset. RESULTS: We detected several differences in MS astrocytes including: (i) enrichment of genes associated with neurodegeneration, (ii) increased mitochondrial fission, (iii) increased production of superoxide and MS-related proinflammatory chemokines, (iv) impaired uptake and enhanced release of glutamate, (v) increased electron transport capacity and proton leak, in line with the increased oxidative stress, and (vi) a distinct metabolic profile, with a deficiency in amino acid catabolism and increased sphingolipid metabolism, which have already been linked to MS. INTERPRETATION: Here we describe the metabolic profile of iPSC-derived astrocytes from PwMS and validate this model as a very powerful tool to study disease mechanisms and to perform non-invasive drug targeting assays in vitro. Our findings recapitulate several disease features described in patients and provide new mechanistic insights into the metabolic rewiring of astrocytes in MS, which could be targeted in future therapeutic studies. ANN NEUROL 2022;91:652-669.


Asunto(s)
Células Madre Pluripotentes Inducidas , Esclerosis Múltiple , Animales , Astrocitos/metabolismo , Ácido Glutámico/metabolismo , Humanos , Células Madre Pluripotentes Inducidas/metabolismo , Ratones , Mitocondrias/metabolismo , Esclerosis Múltiple/patología
19.
mBio ; 13(1): e0347821, 2022 02 22.
Artículo en Inglés | MEDLINE | ID: mdl-35073735

RESUMEN

Trans-sialidases (TS) are unusual enzymes present on the surface of Trypanosoma cruzi, the causative agent of Chagas disease. Encoded by the largest gene family in the T. cruzi genome, only few members of the TS family have catalytic activity. Active trans-sialidases (aTS) are responsible for transferring sialic acid from host glycoconjugates to mucins, also present on the parasite surface. The existence of several copies of TS genes has impaired the use of reverse genetics to study this highly polymorphic gene family. Using CRISPR-Cas9, we generated aTS knockout cell lines displaying undetectable levels of TS activity, as shown by sialylation assays and labeling with antibodies that recognize sialic acid-containing mucins. In vitro infection assays showed that disruption of aTS genes does not affect the parasite's capacity to invade cells or to escape from the parasitophorous vacuole but resulted in impaired differentiation of amastigotes into trypomastigotes and parasite egress from the cell. When inoculated into mice, aTS mutants were unable to establish infection even in the highly susceptible gamma interferon (IFN-γ) knockout mice. Mice immunized with aTS mutants were fully protected against a challenge infection with the virulent T. cruzi Y strain. Altogether, our results confirmed the role of aTS as a T. cruzi virulence factor and indicated that aTS play a major role during the late stages of intracellular development and parasite egress. Notably, mutants lacking TS activity are completely avirulent in animal models of infection and may be used as a live attenuated vaccine against Chagas disease. IMPORTANCE Trypanosoma cruzi is the causative agent of Chagas disease, a neglected tropical disease that affects approximately 6 to 8 million people and for which there is no effective treatment or vaccine. The parasite expresses a family of surface proteins, named trans-sialidases, responsible for transferring sialic acid from host glycoconjugates to parasite mucins. Although recognized as a main virulence factor, the multiple roles of these proteins during infection have not yet been fully characterized, mainly because the presence of several copies of aTS genes has impaired their study using reverse genetics. By applying CRISPR-Cas9, we generated aTS knockout parasites and showed that, although aTS parasite mutants were able to infect cells in vitro, they have an impaired capacity to egress from the infected cell. Importantly, aTS mutants lost the ability to cause infection in vivo but provided full protection against a challenge infection with a virulent strain.


Asunto(s)
Enfermedad de Chagas , Parásitos , Trypanosoma cruzi , Animales , Ratones , Trypanosoma cruzi/genética , Parásitos/metabolismo , Ácido N-Acetilneuramínico/metabolismo , Glicoproteínas/metabolismo , Enfermedad de Chagas/parasitología , Neuraminidasa , Mucinas/metabolismo , Factores de Virulencia , Mamíferos/metabolismo
20.
Brain Res Bull ; 181: 55-64, 2022 04.
Artículo en Inglés | MEDLINE | ID: mdl-35041849

RESUMEN

Believed to cause damage to the nervous system and possibly being associated with neurodegenerative diseases, deltamethrin (DM) is a type II pyrethroid used in pest control, public health, home environment, and vector control. The objective of this study was to evaluate the motor, cognitive and emotional changes associated with dopaminergic and BDNF imbalance after DM exposure in rats. Sixty Wistar rats (9-10 months-old) were used, under Ethics Committee on Animal Research license (ID 19/2017). The animals were randomly divided into four groups: control (CTL, 0.9% saline), DM2 (2 mg DM in 1.6 mL 0.9% saline), DM4 (4 mg of DM in 1.6 mL of 0.9% saline), and DM8 (8 mg of DM in 1.6 mL of 0.9% saline). DM groups were submitted to 9 or 15 inhalations, one every 48 h. Half of the animals from each group were randomly selected and perfused 24 h after the 9th or 15th inhalation. Throughout the experiment, the animal's behavior were evaluated using catalepsy test, open field, hole-board test, Modified Elevated Plus Maze, and social interaction. At the end of the experiments, the rats were perfused transcardially and their brains were processed for Tyrosine Hydroxylase (TH) and Brain derived neurotrophic factor (BDNF) immunohistochemistries. The animals submitted to 9 inhalations of DM showed a reduction in immunoreactivity for TH in the Substantia nigra pars compacta (SNpc), ventral tegmental area (VTA), and dorsal striatum (DS) areas, and an increase in BDNF in the DS and CA1, CA3 and dentate gyrus (DG) hippocampal areas. Conversely, the animals submitted to 15 inhalations of DM showed immunoreactivity reduced for TH in the SNpc and VTA, and an increase in BDNF in the hippocampal areas (CA3 and DG). Our results indicate that the DM inhalation at different periods induce motor and cognitive impairments in rats. Such alterations were accompanied by dopaminergic system damage and a possible dysfunction on synaptic plasticity.


Asunto(s)
Ansiedad/inducido químicamente , Factor Neurotrófico Derivado del Encéfalo/efectos de los fármacos , Encéfalo/efectos de los fármacos , Disfunción Cognitiva/inducido químicamente , Insecticidas/farmacología , Trastornos de la Memoria/inducido químicamente , Actividad Motora/efectos de los fármacos , Síndromes de Neurotoxicidad/etiología , Nitrilos/farmacología , Piretrinas/farmacología , Tirosina 3-Monooxigenasa/efectos de los fármacos , Animales , Conducta Animal/efectos de los fármacos , Modelos Animales de Enfermedad , Dopamina/metabolismo , Exposición por Inhalación , Insecticidas/administración & dosificación , Nitrilos/administración & dosificación , Piretrinas/administración & dosificación , Distribución Aleatoria , Ratas , Ratas Wistar , Conducta Social
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