44 research outputs found
Melanoma maligno anorrectal: Resección local amplia con colgajo V-Y
Mujer de 69 años, sin antecedentes reseñables, remitida a consultas de cirugía colorrectal por rectorragia y proctalgia asociada a aparición de tumoración perianal. Presenta a la exploración una lesión nodular perianal no pigmentada, de consistencia dura, ulcerada y friable, con base de implantación a nivel del canal anal bajo. Se biopsia y se completa el estudio con una colonoscopia, que resulta normal, y pruebas de imagen mediante RMN y TC de extensión. En el informe anatomopatológico presenta fragmentos de mucosa escamosa con infiltración del tejido subepitelial por proliferación celular atípica con inmunohistoquímica compatible para melanoma maligno. El TC de extensión es negativo y la RMN pélvica descarta afectación del aparato esfinteriano
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Automated CT and MRI Liver Segmentation and Biometry Using a Generalized Convolutional Neural Network.
PurposeTo assess feasibility of training a convolutional neural network (CNN) to automate liver segmentation across different imaging modalities and techniques used in clinical practice and apply this to enable automation of liver biometry.MethodsWe trained a 2D U-Net CNN for liver segmentation in two stages using 330 abdominal MRI and CT exams acquired at our institution. First, we trained the neural network with non-contrast multi-echo spoiled-gradient-echo (SGPR)images with 300 MRI exams to provide multiple signal-weightings. Then, we used transfer learning to generalize the CNN with additional images from 30 contrast-enhanced MRI and CT exams.We assessed the performance of the CNN using a distinct multi-institutional data set curated from multiple sources (n = 498 subjects). Segmentation accuracy was evaluated by computing Dice scores. Utilizing these segmentations, we computed liver volume from CT and T1-weighted (T1w) MRI exams, and estimated hepatic proton- density-fat-fraction (PDFF) from multi-echo T2*w MRI exams. We compared quantitative volumetry and PDFF estimates between automated and manual segmentation using Pearson correlation and Bland-Altman statistics.ResultsDice scores were 0.94 ± 0.06 for CT (n = 230), 0.95 ± 0.03 (n = 100) for T1w MR, and 0.92 ± 0.05 for T2*w MR (n = 169). Liver volume measured by manual and automated segmentation agreed closely for CT (95% limit-of-agreement (LoA) = [-298 mL, 180 mL]) and T1w MR (LoA = [-358 mL, 180 mL]). Hepatic PDFF measured by the two segmentations also agreed closely (LoA = [-0.62%, 0.80%]).ConclusionsUtilizing a transfer-learning strategy, we have demonstrated the feasibility of a CNN to be generalized to perform liver segmentations across different imaging techniques and modalities. With further refinement and validation, CNNs may have broad applicability for multimodal liver volumetry and hepatic tissue characterization
Ligand-Based Virtual Screening and Molecular Docking of Benzimidazoles as Potential Inhibitors of Triosephosphate Isomerase Identified New Trypanocidal Agents
Trypanosoma cruzi (T. cruzi) is a parasite that affects humans and other mammals. T. cruzi depends on glycolysis as a source of adenosine triphosphate (ATP) supply, and triosephosphate isomerase (TIM) plays a key role in this metabolic pathway. This enzyme is an attractive target for the design of new trypanocidal drugs. In this study, a ligand-based virtual screening (LBVS) from the ZINC15 database using benzimidazole as a scaffold was accomplished. Later, a molecular docking on the interface of T. cruzi TIM (TcTIM) was performed and the compounds were grouped by interaction profiles. Subsequently, a selection of compounds was made based on cost and availability for in vitro evaluation against blood trypomastigotes. Finally, the compounds were analyzed by molecular dynamics simulation, and physicochemical and pharmacokinetic properties were determined using SwissADME software. A total of 1604 molecules were obtained as potential TcTIM inhibitors. BP2 and BP5 showed trypanocidal activity with half-maximal lytic concentration (LC50) values of 155.86 and 226.30 µM, respectively. Molecular docking and molecular dynamics simulation analyzes showed a favorable docking score of BP5 compound on TcTIM. Additionally, BP5 showed a low docking score (−5.9 Kcal/mol) on human TIM compared to the control ligand (−7.2 Kcal/mol). Both compounds BP2 and BP5 showed good physicochemical and pharmacokinetic properties as new anti-T. cruzi agents. View Full-Tex
Purificación y evaluación de la proteína p25 como antígeno recombinate en la dectección del virus de la artritis encefalitis caprina (AEC): Purificação e avaliação da proteína p25 do vírus da artrite encefalite caprina (CAE)
Para emplearse como antígeno en inmunoensayo indirecto, se purificó la proteína p25 recombinante del virus de la artritis encefalitis caprina mediante cromatografía de afinidad a iones metálicos inmovilizados. Se desarrollaron y estandarizaron las mejores condiciones que permitieron su fiabilidad, para después ser validada con un total de 46 muestras positivas y negativas de referencia. Se estableció la concentración de 4 µg/ml como óptima para la sensibilización de las microplacas. La robustez del ELISA se demostró utilizando como diseño el modelo de Youden y Stainer, y aplicando el criterio del comité de Secretaría de Salud. La concordancia respecto a un estuche comercial fue del 71.73 %, en cuanto a la sensibilidad y especificidad fue del 59.37 % y 100 %, respectivamente. Además, no se presentaron reacciones cruzadas para 3 antígenos probados previamente. Por lo tanto, se concluye que el método de ELISA recombinante implementado en este trabajo, es un método excelente, sencillo, barato y específico para el diagnóstico y tamizaje de la artritis encefalitis caprina, ya que disminuye las reacciones cruzadas
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A multicenter assessment of interreader reliability of LI-RADS version 2018 for MRI and CT
Background: Various limitations have impacted research evaluating reader agreement
for Liver Imaging-Reporting and Data System (LI-RADS).
Purpose: To assess reader agreement of LI-RADS in an international multi-center, multireader setting using scrollable images.
Materials and Methods: This retrospective study used de-identified clinical multiphase
CT and MRI examinations and reports with at least one untreated observation from six
institutions and three countries; only qualifying examinations were submitted.
Examination dates were October 2017 – August 2018 at the coordinating center. One
untreated observation per examination was randomly selected using observation
identifiers, and its clinically assigned features were extracted from the report. The
corresponding LI-RADS v2018 category was computed as a re-scored clinical read. Each
examination was randomly assigned to two of 43 research readers who independently
scored the observation. Agreement for an ordinal modified four-category LI-RADS scale
(LR-1/2, LR-3, LR-4, LR-5/M/tumor in vein) was computed using intra-class correlation
coefficients (ICC). Agreement was also computed for dichotomized malignancy (LR-4/LR5/LR-M/LR-tumor in vein), LR-5, and LR-M. Agreement was compared between researchversus-research reads and research-versus-clinical reads.
Results: 484 patients (mean age, 62 years ±10 [SD]; 156 women; 93 CT, 391 MRI) were
included. ICCs for ordinal LI-RADS, dichotomized malignancy, LR-5, and LR-M were 0.68
(95% CI: 0.62, 0.74), 0.63 (95% CI: 0.56, 0.71), 0.58 (95% CI: 0.50, 0.66), and 0.46 (95%
CI: 0.31, 0.61) respectively. Research-versus-research reader agreement was higher
than research-versus-clinical agreement for modified four-category LI-RADS (ICC, 0.68
vs. 0.62, P = .03) and for dichotomized malignancy (ICC, 0.63 vs. 0.53, P = .005), but not
for LR-5 (P = .14) or LR-M (P = .94).
Conclusion: There was moderate agreement for Liver Imaging-Reporting and Data
System v2018 overall. For some comparisons, research-versus-research reader
agreement was higher than research-versus-clinical reader agreement, indicating
differences between the clinical and research environments that warrant further study
Global disparities in surgeons’ workloads, academic engagement and rest periods: the on-calL shIft fOr geNEral SurgeonS (LIONESS) study
: The workload of general surgeons is multifaceted, encompassing not only surgical procedures but also a myriad of other responsibilities. From April to May 2023, we conducted a CHERRIES-compliant internet-based survey analyzing clinical practice, academic engagement, and post-on-call rest. The questionnaire featured six sections with 35 questions. Statistical analysis used Chi-square tests, ANOVA, and logistic regression (SPSS® v. 28). The survey received a total of 1.046 responses (65.4%). Over 78.0% of responders came from Europe, 65.1% came from a general surgery unit; 92.8% of European and 87.5% of North American respondents were involved in research, compared to 71.7% in Africa. Europe led in publishing research studies (6.6 ± 8.6 yearly). Teaching involvement was high in North America (100%) and Africa (91.7%). Surgeons reported an average of 6.7 ± 4.9 on-call shifts per month, with European and North American surgeons experiencing 6.5 ± 4.9 and 7.8 ± 4.1 on-calls monthly, respectively. African surgeons had the highest on-call frequency (8.7 ± 6.1). Post-on-call, only 35.1% of respondents received a day off. Europeans were most likely (40%) to have a day off, while African surgeons were least likely (6.7%). On the adjusted multivariable analysis HDI (Human Development Index) (aOR 1.993) hospital capacity > 400 beds (aOR 2.423), working in a specialty surgery unit (aOR 2.087), and making the on-call in-house (aOR 5.446), significantly predicted the likelihood of having a day off after an on-call shift. Our study revealed critical insights into the disparities in workload, access to research, and professional opportunities for surgeons across different continents, underscored by the HDI
La catalogación del patrimonio minero industrial de la cuenca minera de Riotinto mediante la aplicación del Sistema de Información Geográfico (SIG)
The aim of this paper is to present the cataloguing work of the mining and industrial heritage of the Riotinto mining bowl during the last 300 years, since the reopening of the mines during the Borbon dynasty in 1725 until the end of the mining activities in 2002. This work has been done by means of the Geographical Information Systems (SIG). Emphasizing the most important period, the British stage between 1873 and 1954, when the mines were worked by The Rio Tinto Company Limited. The analysis of the information relating geographical and thematic variables has been achieved with this system. Finally this GIS will provide an important tool for spatial planning.En este artículo se da a conocer el trabajo desarrollado en la catalogación mediante el empleo de Sistemas de Información Geográfica (SIG) del importante Patrimonio Minero Industrial generado en la cuenca minera de Riotinto en los últimos 300 años, desde la reapertura de las minas en época borbónica en 1725 hasta el fin de la actividad minera en 2002. Destaca por su importancia el período británico comprendido entre 1873 y 1954, cuando las minas fueron explotadas por Río Tinto Company Limited. Así, además de la catalogación de los bienes y su correcta representación cartográfica, hemos pretendido con el empleo de este sistema conseguir un análisis de la nformación relacionando las variables geográficas y temáticas. Por último, este SIG dotará a la administración autonómica de una importante herramienta para la ordenación del territorio en materia de cultura
Characterization of Sodium Channel Peptides Obtained from the Venom of the Scorpion <i>Centruroides bonito</i>
Five peptides were isolated from the venom of the Mexican scorpion Centruroides bonito by chromatographic procedures (molecular weight sieving, ion exchange columns, and HPLC) and were denoted Cbo1 to Cbo5. The first four peptides contain 66 amino acid residues and the last one contains 65 amino acids, stabilized by four disulfide bonds, with a molecular weight spanning from about 7.5 to 7.8 kDa. Four of them are toxic to mice, and their function on human Na+ channels expressed in HEK and CHO cells was verified. One of them (Cbo5) did not show any physiological effects. The ones toxic to mice showed that they are modifiers of the gating mechanism of the channels and belong to the beta type scorpion toxin (β-ScTx), affecting mainly the Nav1.6 channels. A phylogenetic tree analysis of their sequences confirmed the high degree of amino acid similarities with other known bona fide β-ScTx. The envenomation caused by this venom in mice is treated by using commercially horse antivenom available in Mexico. The potential neutralization of the toxic components was evaluated by means of surface plasmon resonance using four antibody fragments (10FG2, HV, LR, and 11F) which have been developed by our group. These antitoxins are antibody fragments of single-chain antibody type, expressed in E. coli and capable of recognizing Cbo1 to Cbo4 toxins to various degrees
EcoBag reusable bags
El presente proyecto es una propuesta innovadora de solución para reducir la contaminación ambiental ocasionada por el desecho de las bolsas plásticas de uno solo uso. Con la finalidad, de validar la viabilidad del proyecto se realizó una investigación en fuentes secundarias y primarias donde se identificó en el Perú se consume 3000 millones de bolsas plásticas al año que producen 1 tonelada de CO2 ocasionado problemas de salud y contaminación ambiental.
En este sentido, el proyecto propone la creación, fabricación y comercialización de bolsas reutilizables de uso multifuncional, que estarán a la venta en los supermercados y en el canal online. Por consiguiente, los productos están orientados a satisfacer las necesidades del segmento de usuarias que son mujeres 25 a 55 años de edad del NSE A, B y C1 que representan el tamaño de mercado total de 810,973 personas en Lima Metropolitana.
Cabe indicar, que el proyecto promete un ingreso anual de S/. 1,028,611 soles en el primer año de operaciones con un crecimiento anual en ventas de 4% a 4.5% para los años siguientes.
Por lo tanto, el proyecto es viable y rentable porque el valor actual neto del flujo de caja financiero es S/. 232,043 soles, que es la rentabilidad en unidades monetarias que el proyecto genera para los accionistas y rinde una tasa interna de retorno de 52% mayor al costo de oportunidad del capital.This project proposes an innovative solution to reduce the environmental pollution caused by single-use plastic bag waste. In order to validate the viability of this project, a study using secondary and primary sources was completed which demonstrated that each year Peru uses 3000 million plastic bags which produces 1 ton of CO2 causing health problems and environmental pollution.
Following this, our project proposes the creation, manufacturing and commercialization of reusable and multiuse bags, which will be for sale in supermarkets and online. Our products will be orientated towards satisfying the needs of a segment of users; which are women between 25 to 55 years old in socio-economic levels A, B and C1, which represents a total market size of 810,973 people in Metropolitan Lima.
It should be noted that the project promises an annual income of S /. 1,028,611 soles in the first year of operations with annual sales growth of 4% to 4.5% for the following years.
Therefore, the project is viable and profitable because the net present value of the financial cash flow is S /. 232,043 soles, which is the return on monetary units that the project generates for shareholders and yields an internal rate of return of 52% higher than the opportunity cost of capital.Trabajo de investigació