RESUMO

Neurodegenerative diseases, tauopathies, constitute a serious global health problem. The etiology of these diseases is unclear and an increase in their incidence has been projected in the next 30 years. Therefore, the study of the molecular mechanisms that might stop these neurodegenerative processes is very relevant. Classification of neurodegenerative diseases using Machine and Deep Learning algorithms has been widely studied for medical imaging such as Magnetic Resonance Imaging. However, post-mortem immunofluorescence imaging studies of the brains of patients have not yet been used for this purpose. These studies may represent a valuable tool for monitoring aberrant chemical changes or pathological post-translational modifications of the Tau polypeptide. We propose a Convolutional Neural Network pipeline for the classification of Tau pathology of Alzheimer's disease and Progressive Supranuclear Palsy by analyzing post-mortem immunofluorescence images with different Tau biomarkers performed with models generated with the architecture ResNet-IFT using Transfer Learning. These models' outputs were interpreted with interpretability algorithms such as Guided Grad-CAM and Occlusion Analysis. To determine the best classifier, four different architectures were tested. We demonstrated that our design was able to classify diseases with an accuracy of 98.41% on average whilst providing an interpretation concerning the proper classification involving different structural patterns in the immunoreactivity of the Tau protein in NFTs present in the brains of patients with Progressive Supranuclear Palsy and Alzheimer's disease.

RESUMO

Efforts have been made to diagnose and predict the course of different neurodegenerative diseases through various imaging techniques. Particularly tauopathies, where the tau polypeptide is a key participant in molecular pathogenesis, have significantly increased their morbidity and mortality in the human population over the years. However, the standard approach to exploring the phenomenon of neurodegeneration in tauopathies has not been directed at understanding the molecular mechanism that causes the aberrant polymeric and fibrillar behavior of the tau protein, which forms neurofibrillary tangles that replace neuronal populations in the hippocampal and cortical regions. The main objective of this work is to implement a novel quantification protocol for different biomarkers based on pathological post-translational modifications undergone by tau in the brains of patients with tauopathies. The quantification protocol consists of an adaptation of the U-Net neural network architecture. We used the resulting segmentation masks for the quantification of combined fluorescent signals of the different molecular changes tau underwent in neurofibrillary tangles. The quantification considers the neurofibrillary tangles as an individual study structure separated from the rest of the quadrant present in the images. This allows us to detect unconventional interaction signals between the different biomarkers. Our algorithm provides information that will be fundamental to understanding the pathogenesis of dementias with another computational analysis approach in subsequent studies.

RESUMO

Among the most frequent nosocomial infections associated with polyresistant bacteria and with a worse prognosis, are those produced by Pseudomonas aeruginosa. This bacterium has a high capacity to adapt to adverse conditions such as pH and osmolarity of urine. Pseudomonas aeruginosa is one of the main pathogens involved in nosocomial infections and immunosuppressed patients. This bacterium is considered an opportunistic infectious agent that has diverse mechanisms of pathogenicity, as well as resistance to antimicrobials, which contributes to the difficulty in the treatment of these infections. In the present bibliographic review, the taxonomy, pathogenicity mechanisms and resistance genes of P. aeruginosa are analyzed. Likewise, the micro-environmental factors of the urinary infection produced by this bacterium are approached, making an approach to the understanding of the pathophysiological bases of this infection.

Assuntos

RESUMO

Resumen Dentro de las infecciones nosocomiales más frecuentes asociadas a bacterias multi-resistentes y de peor pronóstico, se encuentran las producidas por Pseudomonas aeruginosa. Esta bacteria posee una alta capacidad de adaptación a condiciones adversas como por ejemplo el pH y la osmolaridad de la orina. Pseudomonas aeruginosa es uno de los principales patógenos implicados en infecciones nosocomiales y de pacientes inmunosuprimidos. Esta bacteria se considera un agente infeccioso oportunista que posee diversos mecanismos de patogenicidad, así como de resistencia a antimicrobianos, lo que contribuye a la dificultad en el tratamiento de estas infecciones. En la presente revisión bibliográfica se analizan la taxonomía, los mecanismos de patogenicidad y genes de resistencia de P. aeruginosa. Así también, se abordan los factores microambientales de la infección urinaria producida por esta bacteria, haciendo un acercamiento al entendimiento de las bases fisiopatológicas de esta infección.

Among the most frequent nosocomial infections associated with polyresistant bacteria and with a worse prognosis, are those produced by Pseudomonas aeruginosa. This bacterium has a high capacity to adapt to adverse conditions such as pH and osmolarity of urine. Pseudomonas aeruginosa is one of the main pathogens involved in nosocomial infections and immunosuppressed patients. This bacterium is considered an opportunistic infectious agent that has diverse mechanisms of pathogenicity, as well as resistance to antimicrobials, which contributes to the difficulty in the treatment of these infections. In the present bibliographic review, the taxonomy, pathogenicity mechanisms and resistance genes of P. aeruginosa are analyzed. Likewise, the micro-environmental factors of the urinary infection produced by this bacterium are approached, making an approach to the understanding of the pathophysiological bases of this infection.

Assuntos

RESUMO

For many years, it has been hypothesized that Neotropical migrants breeding in the United States and Canada accumulate organochlorine pesticides (OCPs) while on their wintering grounds in Latin America. We investigated the seasonal accumulation of persistent organic pollutant (POPs) in migrant and resident passerines in Texas, Yucatán, and Costa Rica collected during the fall, winter, and spring from 2011 to 2013. A total of 153 birds were collected, and all contained detectable levels of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and OCPs with dichlorodiphenyldichloroethylene (DDE) being the most predominant pesticide. OCPs and PCBs were the predominant contaminants, accounting for ≥80 % of the total POPs burden, whereas PBDEs accounted for ≤16 %. Only spring migrants from Texas had significantly greater DDE concentrations (64.6 ng/g dry weight [dw]) than migrants collected in Costa Rica (23.2 ng/g dw). Resident birds in Texas had significantly greater levels of DDE (121 ng/g dw) and ΣPBDEs (34.8 ng/g dw) compared with residents in Yucatán and Costa Rica. For ΣPCBs, resident birds from Costa Rica had significantly lower concentrations (9.60 ng/g dw) compared with their migrant counterparts (43.7 ng/g dw) and residents from Texas (48.3 ng/g dw) and the Yucatán (32.1 ng/g dw). Migrant and resident passerines had similar congener profiles for PCBs and PBDEs suggesting similar exposure and retention of these contaminants. No significant accumulation of DDE was observed in migrants while on their wintering grounds. Relatively high concentrations of PBDEs in resident birds from Costa Rica warrant future studies of PBDE contamination in Latin America.

Assuntos

RESUMO

Internal root resorption (IRR) is a rare pulp disease. Its etiology involves late pulpal inflammations and trauma, among others. IRR may also show some symptoms, and is usually detected by X-rays. However, its diagnosis is significantly improved by the use of cone beam computed tomography (CBCT). The objective of this case report was to account for the diagnosis and management of an internal root resorption without perforation. The patient, a 26-year-old male, went to the School of Dentistry at Universidad Andres Bello, Concepción, without having symptoms in the tooth 1.1. Anamnesis revealed the presence of previous symptoms. CBCT examination showed absence of bowl-shaped calcified dentin tissue on the inner walls of the root canal with apical lesion but without perforation of surrounding tissues. Endodontic treatment was performed using the following methods: irrigation of the root canal with 2 percent chlorhexidine (CHX) using a Max-i-probe cannula and simultaneous cavitation of the irrigant Then calcium hydroxide (CH) was applied as intracanal medication for a week and Schilder’s technique for vertical compaction was used. The patient was checked after one week and then after six months. He did not have any symptoms. Early diagnosis using modern imaging equipment, appropriate use of ultrasound for chemomechanical debridement and thermoplastic filling techniques contribute to a more favorable prognosis of patients with internal root resorption...

La reabsorción radicular interna (RRI) es una condición pulpar poco común, cuyo origen etiológico incluye procesos inflamatorios tardíos de la pulpa, traumatismos, entre otros; por otra parte ésta podría presentar sintomatología. Generalmente es detectada por hallazgo radiográfico, sin embargo, requiere de un mejor método de diagnóstico por imagen como es la tomografía computarizada cone beam (TCCB). El objetivo de este reporte de caso fue detallar el diagnóstico y manejo de una reabsorción radicular interna sin perforación. El paciente de sexo masculino, 26 años de edad acudió a la Facultad de Odontología de la Universidad Andrés Bello sede Concepción, sin presentar síntomas en el diente 1.1. La anamnesis refirió presencia de sintomatología con anterioridad. La evaluación mediante la TCCB demostró ausencia de tejido dentinario calcificado en forma de cuenco en las paredes internas del conducto radicular con presencia de lesión apical sin evidenciar perforación hacia tejidos circundantes. Se realizó el tratamiento endodóntico, usando los siguientes métodos: el conducto radicular se irrigó con Clorhexidina (CHX) al 2 por ciento usando cánula Max-i-probe y simultáneamente fue realizada la cavitación del irrigante, luego se colocó Hidróxido de Calcio (HC) como medicación intraconducto por una semana. Se usó la técnica de compactación vertical de Schilder más un control del paciente a la semana y a los 6 meses. El paciente no presentó sintomatología. El diagnóstico temprano mediante herramientas imaginológicas contemporáneas, la utilización del ultrasonido para el desbridamiento químico-mecánico y las técnicas de obturación termoplásticas usadas acorde al caso hacen que las piezas con reabsorción radicular interna tengan un pronóstico más favorable...

Assuntos