Browsing by Author "Andía Kohnenkampf, Marcelo Edgardo"

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    A new discrete dipole kernel for quantitative susceptibility mapping
    (2018) Milovic Fabregat, Carlos Andrés; Acosta-Cabronero, Julio; Miguel Pinto, Jose; Mattern, Hendrik; Andía Kohnenkampf, Marcelo Edgardo; Uribe Arancibia, Sergio A.; Tejos Núñez, Cristián Andrés
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    A realistic MR compatible aortic phantom to validate hemodynamic parameters from MRI data: aortic coarctation patients comparison using catheterization
    (2015) Urbina, Jesus; Sotelo Parraguez, Julio Andrés; Tejos Núñez, Cristián Andrés; Irarrázaval Mena, Pablo; Andía Kohnenkampf, Marcelo Edgardo; Razavi, Reza; Valverde, Israel; Uribe Arancibia, Sergio A.
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    A Survey on Deep Learning and Explainability for Automatic Report Generation from Medical Images
    (2022) Messina, Pablo; Pino, Pablo; Parra Santander, Denis; Soto Arriaza, Álvaro Marcelo; Besa, Cecilia; Uribe Arancibia, Sergio A.; Andía Kohnenkampf, Marcelo Edgardo; Tejos Núñez, Cristián Andrés; Prieto Vásquez, Claudia; Capurro, Daniel
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    Accelerating the acquisition of the 3D Dual Cardiac Phase technique using RPE trajectories
    (2014) Letelier Farías, Karis del Pilar; Andía Kohnenkampf, Marcelo Edgardo; Tejos Núñez, Cristián Andrés; Irarrázaval Mena, Pablo; Prieto Vásquez, Claudia; Uribe Arancibia, Sergio A.
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    Advances in molecular imaging of atherosclerosis and myocardial infarction: shedding new light on in vivo cardiovascular biology
    (2012) Phinikaridou, Alkystis; Andía Kohnenkampf, Marcelo Edgardo; Shah, Ajay M.; Botnar, René M.
    Molecular imaging of the cardiovascular system heavily relies on the development of new imaging probes and technologies to facilitate visualization of biological processes underlying or preceding disease. Molecular imaging is a highly active research discipline that has seen tremendous growth over the past decade. It has broadened our understanding of oncologic, neurologic, and cardiovascular diseases by providing new insights into the in vivo biology of disease progression and therapeutic interventions. As it allows for the longitudinal evaluation of biological processes, it is ideally suited for monitoring treatment response. In this review, we will concentrate on the major accomplishments and advances in the field of molecular imaging of atherosclerosis and myocardial infarction with a special focus on magnetic resonance imaging.
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    Attenuation of atherogenic apo B-48-dependent hyperlipidemia and high density lipoprotein remodeling induced by vitamin C and E combination and their beneficial effect on lethal ischemic heart disease in mice
    (2018) Contreras-Duarte, Susana; Chen, P.; Andía Kohnenkampf, Marcelo Edgardo; Uribe Arancibia, Sergio A.; Irarrázaval Mena, Pablo; Kopp, S.; Kern, S.; Marsche, G.; Busso, Dolores; Rigotti Rivera, Attilio
    Abstract Background and aims Atherosclerotic cardiovascular disease is highly prevalent and its underlying pathogenesis involves dyslipidemia including pro-atherogenic high density lipoprotein (HDL) remodeling. Vitamins C and E have been proposed as atheroprotective agents for cardiovascular disease management. However, their effects and benefits on high density lipoprotein function and remodeling are unknown. In this study, we evaluated the role of vitamin C and E on non HDL lipoproteins as well as HDL function and remodeling, along with their effects on inflammation/oxidation biomarkers and atherosclerosis in atherogenic diet-fed SR-B1 KO/ApoER61h/h mice. Methods and results: Mice were pre-treated for 5 weeks before and during atherogenic diet feeding with vitamin C and E added to water and diet, respectively. Compared to a control group, combined vitamin C and E administration reduced serum total cholesterol and triglyceride levels by decreasing apo B-48-containing lipoproteins, remodeled HDL particles by reducing phospholipid as well as increasing PON1 and apo D content, and diminished PLTP activity and levels. Vitamin supplementation improved HDL antioxidant function and lowered serum TNF-α levels. Vitamin C and E combination attenuated atherogenesis and increased lifespan in atherogenic diet-fed SR-B1 KO/ApoER61h/h mice. Conclusions Vitamin C and E administration showed significant lipid metabolism regulating effects, including HDL remodeling and decreased levels of apoB-containing lipoproteins, in mice. In addition, this vitamin supplementation generated a cardioprotective effect in a murine model of severe and lethal atherosclerotic ischemic heart disease.
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    Calcium (Ca2+) waves data calibration and analysis using image processing techniques
    (2013) Milovic Fabregat, Carlos Andrés; Oses, Carolina; Villalón, Manuel J.; Uribe Arancibia, Sergio A.; Prieto Vásquez, Claudia; Andía Kohnenkampf, Marcelo Edgardo; Irarrázaval Mena, Pablo; Tejos Núñez, Cristián Andrés; Lizama, Carlos
    Abstract Background Calcium (Ca2+) propagates within tissues serving as an important information carrier. In particular, cilia beat frequency in oviduct cells is partially regulated by Ca2+ changes. Thus, measuring the calcium density and characterizing the traveling wave plays a key role in understanding biological phenomena. However, current methods to measure propagation velocities and other wave characteristics involve several manual or time-consuming procedures. This limits the amount of information that can be extracted, and the statistical quality of the analysis. Results Our work provides a framework based on image processing procedures that enables a fast, automatic and robust characterization of data from two-filter fluorescence Ca2+ experiments. We calculate the mean velocity of the wave-front, and use theoretical models to extract meaningful parameters like wave amplitude, decay rate and time of excitation. Conclusions Measurements done by different operators showed a high degree of reproducibility. This framework is also extended to a single filter fluorescence experiments, allowing higher sampling rates, and thus an increased accuracy in velocity measurements.
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    Cardiovascular magnetic resonance findings in a pediatric population with isolated left ventricular non-compaction
    (2012) Uribe Arancibia, Sergio A.; Cadavid, Lina; Parra Rojas, Rodrigo Orlando; Urcelay Montecinos, Gonzalo; Heusser Risopatron, Felipe; Andía Kohnenkampf, Marcelo Edgardo; Tejos Núñez, Cristián Andrés; Irarrázaval Mena, Pablo; Hussain, Tarique
    Abstract Background Isolated Left Ventricular Non-compaction (LVNC) is an uncommon disorder characterized by the presence of increased trabeculations and deep intertrabecular recesses. In adults, it has been found that Ejection Fraction (EF) decreases significantly as non-compaction severity increases. In children however, there are a few data describing the relation between anatomical characteristics of LVNC and ventricular function. We aimed to find correlations between morphological features and ventricular performance in children and young adolescents with LVNC using Cardiovascular Magnetic Resonance (CMR). Methods 15 children with LVNC (10 males, mean age 9.7 y.o., range 0.6 - 17 y.o.), underwent a CMR scan. Different morphological measures such as the Compacted Myocardial Mass (CMM), Non-Compaction (NC) to the Compaction (C) distance ratio, Compacted Myocardial Area (CMA) and Non-Compacted Myocardial Area (NCMA), distribution of NC, and the assessment of ventricular wall motion abnormalities were performed to investigate correlations with ventricular performance. EF was considered normal over 53%. Results The distribution of non-compaction in children was similar to published adult data with a predilection for apical, mid-inferior and mid-lateral segments. Five patients had systolic dysfunction with decreased EF. The number of affected segments was the strongest predictor of systolic dysfunction, all five patients had greater than 9 affected segments. Basal segments were less commonly affected but they were affected only in these five severe cases. Conclusion The segmental pattern of involvement of non-compaction in children is similar to that seen in adults. Systolic dysfunction in children is closely related to the number of affected segments.
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    Characterization of hepatic fatty acids using magnetic resonance spectroscopy for the assessment of treatment response to metformin in an eNOS−/− mouse model of metabolic nonalcoholic fatty liver disease/nonalcoholic steatohepatitis
    (2023) Lavin, Begoña; Eykyn, Thomas; Phinikaridou, Alkystis; Xavier, Aline; Kumar, Shravan; Buqué, Xabier; Aspichueta, Patricia; Sing-Long C., Carlos A.; Arrese, Marco; Botnar, René Michael; Andía Kohnenkampf, Marcelo Edgardo
    Nonalcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease worldwide. Liver biopsy remains the gold standard for diagnosis and staging of disease. There is a clinical need for noninvasive diagnostic tools for risk stratification, follow-up, and monitoring treatment response that are currently lacking, as well as preclinical models that recapitulate the etiology of the human condition. We have characterized the progression of NAFLD in eNOS−/− mice fed a high fat diet (HFD) using noninvasive Dixon-based magnetic resonance imaging and single voxel STEAM spectroscopy-based protocols to measure liver fat fraction at 3 T. After 8 weeks of diet intervention, eNOS−/− mice exhibited significant accumulation of intra-abdominal and liver fat compared with control mice. Liver fat fraction measured by 1H-MRS in vivo showed a good correlation with the NAFLD activity score measured by histology. Treatment of HFD-fed NOS3−/− mice with metformin showed significantly reduced liver fat fraction and altered hepatic lipidomic profile compared with untreated mice. Our results show the potential of in vivo liver MRI and 1H-MRS to noninvasively diagnose and stage the progression of NAFLD and to monitor treatment response in an eNOS−/− murine model that represents the classic NAFLD phenotype associated with metabolic syndrome.
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    Combined coronary lumen and vessel wall magnetic resonance imaging with i-T2prep : influence of nitroglycerin
    (2015) Hussain, Tarique; Henningsson, Markus; Butzbach, Britta; Lossnitzer, Dirk; Greil, Gerald F.; Andía Kohnenkampf, Marcelo Edgardo; Botnar, René Michael
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    Development of a tropoelastin-binding MR contrast agent for in vivo imaging of impaired elastogenesis in atherosclerosis
    (2015) Andía Kohnenkampf, Marcelo Edgardo; Botnar, René Michael; Phinikaridou, Alkystis; Lacerda, Sara
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    Effect of Propionibacterium acnes (PA) injection on intervertebral disc degeneration in a rat model : does it mimic modic changes?
    (2017) Zamora Helo, Tomás; Palma, J.; Andía Kohnenkampf, Marcelo Edgardo; García Cañete, Patricia; Wozniak Banchero, Aniela; Solar González, Antonieta Alejandra; Campos, M.
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    Effet de l’injection de Propionibacterium acnes (PA) sur la dégénérescence dans un modèle de rat
    (2017) Zamora Helo, Tomás; Palma, J.; Andía Kohnenkampf, Marcelo Edgardo; García Cañete, Patricia; Wozniak Banchero, Aniela; Solar González, Antonieta Alejandra; Campos, M.
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    Enhancing the Velocity Data From 4D Flow MR Images by Reducing its Divergence
    (2016) Mura, J.; Pino, A. M.; Sotelo Parraguez, Julio Andrés; Valverde, I.; Tejos Núñez, Cristián Andrés; Andía Kohnenkampf, Marcelo Edgardo; Irarrázaval Mena, Pablo; Uribe Arancibia, Sergio A.
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    Erratum to: Embolization of Incompetent Pelvic Veins for the Treatment of Recurrent Varicose Veins in Lower Limbs and Pelvic Congestion Syndrome
    (2013) Meneses Quiroz, Luis Andrés; Fava Peirano, Mario; Diaz, P.; Andía Kohnenkampf, Marcelo Edgardo; Tejos, C.; Irarrázaval Mena, Pablo; Uribe, S.
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    Estudio preliminar de índices ecocardiográficos que permitan optimizar la indicación de resonancia cardíaca en pacientes con tetralogía de Fallot reparada
    (2013) Ferreiro, M.; Toro, L.; Andía Kohnenkampf, Marcelo Edgardo; Zelada, Pamela; Alcántara, A.; Castillo, M. E.; Lagos, R.; Bareño, S.; Uribe, S.
    Introducción: La Tetralogía de Fallot reparada (TOFr) a largo plazo evoluciona frecuentemente con insuficiencia pulmonar (IP). La resonancia magnética cardíaca (RMC) juega un rol fundamental en la indicación de recambio valvular pulmonar destinada a evitar las complicaciones de la IP. Objetivo: El objetivo de este trabajo es buscar qué índice(s) ecocardiográfico(s) permite(n) identificar a los pacientes con TOFr que tienen VD dilatado y fracción de eyección (FE) disminuida en la RMC. Método: En 20 pacientes (9 mujeres, 8-25 años, promedio 15,8 años) con TOFr se realizó ecocardiograma (ECO) y RMC en el Hospital Sótero del Río. Por ECO se obtuvieron mediciones de excursión sistólica máxima anular tricuspídea (TAPSE), onda s tisular, aceleración miocárdica isovolumétrica (IVA), y grado de IP (leve, moderado o severo). Por RMC se midieron la FE, volumen fin de diástole (VFD) del VD y fracción de regurgitación de la arteria pulmonar (FR). Se realizó un análisis estadístico multivariado. Resultados: No se obtuvo ninguna correlación entre algún parámetro de ECO versus VFD o FE del VD. Sin embargo, se encontró un modelo basado en el TAP-SE e IP que en nuestros pacientes pudo predecir el VDF del VD con un r2 = 0.6. (VDF-VD = 8.60*TAPSE + 36.19*IP - 77.213). Al comparar la IP con la FR se encontró que la ecografía puede distinguir correctamente aquellos casos que tienen IP leve de severa (p<0.001), o moderada de severa (p=0.004), pero no puede diferenciar con significancia estadística aquellos casos de IP leve de moderada (p=0.272). Conclusión: En este estudio preliminar se encontró un modelo estadístico basado en el TAPSE e IP que podría ser útil en la selección de pacientes que son derivados para estudio con RMC. La estimación del grado de IP medida por ECO es un parámetro fácil de obtener, sin embargo no siempre es informado en forma categórica (leve, moderado o severo). Si bien este estudio se debe validar en un mayor número de pacientes, éste nos indica la relevancia de algunos parámetros ecocardiográficos que deberían incluirse siempre en el protocolo de evaluación de pacientes con TOFr.
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    Extracellular vesicles through the blood–brain barrier: a review
    (2022) Ramos Zaldívar, Héctor M.; Polakovicova, Iva; Salas-Huenuleo, Edison; Corvalán R., Alejandro; Kogan, Marcelo J.; Yefi Rubio, Claudia Pamela; Andía Kohnenkampf, Marcelo Edgardo
    Extracellular vesicles (EVs) are particles naturally released from cells that are delimited by a lipid bilayer and are unable to replicate. How the EVs cross the Blood–Brain barrier (BBB) in a bidirectional manner between the bloodstream and brain parenchyma remains poorly understood. Most in vitro models that have evaluated this event have relied on monolayer transwell or microfluidic organ-on-a-chip techniques that do not account for the combined effect of all cellular layers that constitute the BBB at different sites of the Central Nervous System. There has not been direct transcytosis visualization through the BBB in mammals in vivo, and evidence comes from in vivo experiments in zebrafish. Literature is scarce on this topic, and techniques describing the mechanisms of EVs motion through the BBB are inconsistent. This review will focus on in vitro and in vivo methodologies used to evaluate EVs transcytosis, how EVs overcome this fundamental structure, and discuss potential methodological approaches for future analyses to clarify these issues. Understanding how EVs cross the BBB will be essential for their future use as vehicles in pharmacology and therapeutics.
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    Fatty acids characterization during non-alcoholic fatty liver disease using magnetic resonance spectroscopy
    (2020) Xavier, Aline Carvalho da Silva; Andía Kohnenkampf, Marcelo Edgardo; Pontificia Universidad Católica de Chile. Escuela de Ingeniería
    Introducción: La enfermedad del hígado graso no-alcohólico (EHGNA) es la enfermedad hepática más común en el mundo y se está convirtiendo en una de las causas más frecuentes de trasplante hepático. Desafortunadamente, el único método disponible para determinar de manera confiable la etapa de esta enfermedad es la biopsia hepática, la cual es invasiva y riesgosa para los pacientes; y además no es representativa de todo el parénquima hepático. Algunos estudios sugieren que diferencias en la composición de la grasa hepática (i.e. los ácidos grasos) están relacionados a la progresión de esta enfermedad. Objetivo: El propósito de este estudio es investigar la composición de los ácidos grasos del hígado durante la progresión de la EHGNA mediante el uso de espectroscopía por resonancia magnética (ERM), un método potencialmente no-invasivo. Metodología: Hemos realizado un estudio de ERM ex-vivo de manera de comparar nuestros resultados con los métodos invasivos estándares. Este estudio ex-vivo se realizó con 2 modelos murinos alimentados con dieta Western y CDAA. Luego, realizamos un estudio in-vivo, y utilizamos el estudio ex-vivo como validación. Finalmente, probamos la viabilidad de realizar nuestras técnicas en resonadores clínicos con voluntarios usando un equipo de 7 Tesla. Resultados: La composición de los ácidos grasos del hígado cambia a medida que la EHGNA progresa de esteatosis a esteatohepatitis, pero permanece invariable durante las diferentes etapas de esteatohepatitis. Utilizando el análisis de componentes principales en los datos de ERM, identificamos los tres grupos clínicos más relevantes: normal, esteatosis y esteatohepatitis. Estos resultados mostraron muy buena concordancia con los resultados de los métodos invasivos estándares. Con la ERM in-vivo, en voluntarios, comprobamos la viabilidad de identificar los peaks de los ácidos grasos en el espectro hepático. Conclusión: Se demostró en modelos animales que es posible detectar la progresión de la esteatosis simple a esteatohepatitis utilizando ERM hepática y que este método tiene potencial para ser utilizado en la clínica, en humanos y potencialmente reemplazar la biopsia hepática.
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    Ferrous Ion oxidation monitoring by using magnetic resonance imaging for bio-oxidation laboratory testing
    (2017) Videla Leiva, Álvaro Rodrigo; Matamala Troncoso, Luis Felipe; Uribe Arancibia, Sergio A.; Andía Kohnenkampf, Marcelo Edgardo
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    Fibrin-Targeted Magnetic Resonance Imaging Allows In Vivo Quantification of Thrombus Fibrin Content and Identifies Thrombi Amenable for Thrombolysis
    (2014) Andía Kohnenkampf, Marcelo Edgardo; Saha, P.; Jenkins, J.; Modarai, B.; Wiethoff, A.; Phinikaridou, A.; Grover, S.; Patel, A.