Desmitificando a los parásitos: hacia una nueva concepción epistemológica del parasitismo y la parasitosis

La relación ciencia-filosofía ha pasado por diferentes etapas, siendo alguna de ellas conflictiva,desconociendo el valor y la importancia de cada una de ellas. La formación humanística de los científicos y la científica de los humanistas es necesaria para un análisis productivo y creativo de estos ámbitos del saber. En la historia de la biofilosofía se puede afirmar que ciertas teorías han sido focalizadas con más interés que otras para su análisis filosófico (ontológico, gnoseológico y/o epistemológico).Se ha profundizado especialmente en teoría evolutiva, sistemática biológica y ecología, entre otras. La parasitología como disciplina biológica ha recibido tardíamente la atención de parasitólogos y epistemólogos. El objetivo de esta ponencia es precisamente plantear la riqueza de la parasitología para su estudio desde lo filosófico y epistemológico, apuntado a su gran caudal conceptual y amplia evidencia empírica.Asociación Parasitológica Argentin

Effect of Different Terpene-Containing Essential Oils on the Proliferation of <i>Echinococcus granulosus</i> Larval Cells

Human cystic echinococcosis remains a major public health problem on several countries and the treatment strategies are not solved. The aim of the present work was to determine the in vitro effect of thymol and Mentha piperita, M. pulegium, and Rosmarinus officinalis essential oils on the proliferation of E. granulosus larval cells. Isolated cells and cellular aggregates were obtained from hydatid cyst's germinal layer and exposed to 1, 5, and 10 μg/ml of thymol and the different essential oils for 7 days. Drug effect was evaluated using test viability and scanning electron microscopy. Control cell culture viability was 2.1 x 10(6) (100%) after 7 days of incubation. At day 7, thymol 5 μg/ml caused a reduction in cell viability of 63% and the essential oils of M. piperita 10 μg/ml, M. pulegium 10 μg/ml, and R. officinalis 10 μg/ml produced a reduction in the viability of 77, 82, and 71%, respectively. Moreover essential oils caused reduction in cell number, collapsed cells, and loss of normal tridimensional composition of the aggregates. Due to the inhibitory effect caused by essential oils on E. granulosus cells we suggested that it would be an effective means for suppression of larval growth.Facultad de Ciencias VeterinariasConsejo Nacional de Investigaciones Científicas y Técnica

In Vitro and In Vivo Effects of Tamoxifen against Larval Stage Echinococcus granulosus

Cystic echinococcosis is a zoonotic infection caused by the larval stage of the cestode Echinococcus granulosus. Chemotherapy currently employs benzimidazoles; however, 40% of cases do not respond favorably. With regard to these difficulties, novel therapeutic tools are needed to optimize treatment in humans. The aim of this work was to explore the in vitro and in vivo effects of tamoxifen (TAM) against E. granulosus. In addition, possible mechanisms for the susceptibility of TAM are discussed in relation to calcium homeostasis, P-glycoprotein inhibition, and antagonist effects on a putative steroid receptor. After 24 h of treatment, TAM, at a low micromolar concentration range (10 to 50 μM), inhibited the survival of E. granulosus protoscoleces and metacestodes. Moreover, we demonstrated the chemotherapeutic and chemopreventive pharmacological effects of the drug. At a dose rate of 20 mg/kg of body weight, TAM induced protection against the infection in mice. In the clinical efficacy studies, a reduction in cyst weight was observed after the administration of 20 mg/kg in mice with cysts developed during 3 or 6 months, compared to that of those collected from control mice. Since the collateral effects of high TAM doses have been largely documented in clinical trials, the use of low doses of this drug as a short-term therapy may be a novel alternative approach for human cystic echinococcosis treatment.Fil: Nicolao, María Celeste. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biologia. Laboratorio de Zoonosis Parasitarias; ArgentinaFil: Elissondo, María Celina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biologia. Laboratorio de Zoonosis Parasitarias; ArgentinaFil: Denegri, Guillermo Maria. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biologia. Laboratorio de Zoonosis Parasitarias; ArgentinaFil: Goya, Alejandra Beatriz. Ministerio de Agricultura, Ganadería, Pesca y Alimento. Servicio Nacional de Sanidad y Calidad Agroalimentaria; ArgentinaFil: Cumino, Andrea Carina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biologia. Laboratorio de Zoonosis Parasitarias; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Química; Argentin

Effect of Different Terpene-Containing Essential Oils on the Proliferation of <i>Echinococcus granulosus</i> Larval Cells

Human cystic echinococcosis remains a major public health problem on several countries and the treatment strategies are not solved. The aim of the present work was to determine the in vitro effect of thymol and Mentha piperita, M. pulegium, and Rosmarinus officinalis essential oils on the proliferation of E. granulosus larval cells. Isolated cells and cellular aggregates were obtained from hydatid cyst's germinal layer and exposed to 1, 5, and 10 μg/ml of thymol and the different essential oils for 7 days. Drug effect was evaluated using test viability and scanning electron microscopy. Control cell culture viability was 2.1 x 10(6) (100%) after 7 days of incubation. At day 7, thymol 5 μg/ml caused a reduction in cell viability of 63% and the essential oils of M. piperita 10 μg/ml, M. pulegium 10 μg/ml, and R. officinalis 10 μg/ml produced a reduction in the viability of 77, 82, and 71%, respectively. Moreover essential oils caused reduction in cell number, collapsed cells, and loss of normal tridimensional composition of the aggregates. Due to the inhibitory effect caused by essential oils on E. granulosus cells we suggested that it would be an effective means for suppression of larval growth.Facultad de Ciencias VeterinariasConsejo Nacional de Investigaciones Científicas y Técnica

Effect of Different Terpene-Containing Essential Oils on the Proliferation of <i>Echinococcus granulosus</i> Larval Cells

Human cystic echinococcosis remains a major public health problem on several countries and the treatment strategies are not solved. The aim of the present work was to determine the in vitro effect of thymol and Mentha piperita, M. pulegium, and Rosmarinus officinalis essential oils on the proliferation of E. granulosus larval cells. Isolated cells and cellular aggregates were obtained from hydatid cyst's germinal layer and exposed to 1, 5, and 10 μg/ml of thymol and the different essential oils for 7 days. Drug effect was evaluated using test viability and scanning electron microscopy. Control cell culture viability was 2.1 x 10(6) (100%) after 7 days of incubation. At day 7, thymol 5 μg/ml caused a reduction in cell viability of 63% and the essential oils of M. piperita 10 μg/ml, M. pulegium 10 μg/ml, and R. officinalis 10 μg/ml produced a reduction in the viability of 77, 82, and 71%, respectively. Moreover essential oils caused reduction in cell number, collapsed cells, and loss of normal tridimensional composition of the aggregates. Due to the inhibitory effect caused by essential oils on E. granulosus cells we suggested that it would be an effective means for suppression of larval growth.Facultad de Ciencias VeterinariasConsejo Nacional de Investigaciones Científicas y Técnica

Improvement of the In Vitro Culture of Echinococcus Granulosus Metacestodes

This work introduces a novel modification to the in vitro experimental vesiculardevelopment of the parasite. Our findings showed that protoscoleces exposed toinsulin developed into microcysts in shorter times. Moreover, a tenfold incrementin the yield of microcysts per tube was observed. An improvement of the in vitroculture of E. granulosus metacestodes was achieved. On the basis of this axenicin vitro system, biochemical, molecular and chemotherapeutical studies of E.granulosus will be greatly facilitated.Fil: Elissondo, María Celina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología. Laboratorio de Zoonosis Parasitarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Pensel, Patricia Eugenia. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología. Laboratorio de Zoonosis Parasitarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Denegri, Guillermo Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología. Laboratorio de Zoonosis Parasitarias; Argentin

Constrastación de un programa de investigación científica en parasitología: reconstrucción de un caso histórico

A partir de la influyente obra de T. Kuhn "The Structure of Scientific Revolutions" (1962) el análisis del desarrollo científico se desplazó progresivamente del contexto justificación al contexto de descubrimiento. Las teorías científicas dejaban de ser, para el análisis, estructuras acabadas y estáticas -para ser estructuras dinámicas y en continua transformación. La historia de la ciencia logra entonces un lugar preponderante como criterio de contrastación de las teorías científicas y los nuevos enfoques en filosofía de la ciencia la incorporan como elemento fundamental. Lakatos en su articulo "La historia de la ciencia y sus reconstrucciones racionales" (1983) toma la conocida frase de Kant: "la filosofía de la ciencia sin historia de la ciencia es vacía; la historia de la ciencia sin filosofía de la ciencia es ciega". Este cambio radical desde una perspectiva normativista acerca de lo que la actividad científica "debe (o debiera) ser" se contrasta en la nueva filosofía de la ciencia, en una actitud descriptivista y mas realista de lo que la práctica científica "es". Para esta última posición no hay más que incursionar en la historia de la ciencia y ver lo que ha pasado. Así es que para el modelo kuhniano la historia de una disciplina científica es una sucesión de paradigmas y de programas de investigación para Lakatos. (Párrafo extraído del texto a modo de resumen)Departamento de Filosofí

La metodología de los programas de investigación científica y el concepto biológico del sistema conservativo

El primer interrogante que se nos planteó al decidir escribir este articulo fue por que la metodología de los programas de investigación científica (en adelante PIC) de Lakatos (1983) seduce de tal manera a investigadores experimentales del campo biológico? Una primera respuesta seria quizás que esta metodología se adecua prima facie con bastante aproximación a lo que hacemos diariamente en el laboratorio y que describe la actividad científica presente. Una segunda posible respuesta seria que es una metodología entendible para los científicos y en cuanto la analizamos hacemos el ejercicio mental de aplicarla a nuestros campos de estudio. Una tercera respuesta es que después de reflexionar un tiempo vemos en la metodología de los PIC un buen marco epistémico para la actividad futura en nuestras respectivas áreas de conocimiento. (Párrafo extraído del texto a modo de resumen)Departamento de Filosofí

Molecular characterization of <i>Sarcocystis</i> spp. in intestine mucosal scrapings and fecal samples of Pampas fox (<i>Lycalopex gymnocercus</i>)

Sarcocystis spp. are obligatory intracellular protozoan parasites which can infect humans and animals. Most of Sarcocystis species were identified based on the detection of muscle cysts in different intermediate hosts (IH). Regarding to natural infection in definitive host, there are few reports which have reached to determining species of Sarcocystis. The present work was aimed to studying the occurrence of Sarcocystis spp. (oocysts and sporocysts) in mucosal scrapings of small intestine and fecal samples of one the most abundant wild canids from South America, Lycalopex gymnocercus (Pampas fox), and to identify the Sarcocystis spp. using molecular tools. A total of 131 free-living L. gymnocercus were sampled in rural areas located in several departments from Buenos Aires province, Argentina. Fecal samples from all the animals and 33 small intestines were analyzed. Fecal and mucosal scrapings samples were analyzed by sugar flotation method and once oocysts or sporocysts were detected, sedimentation was performed and DNA extracted with a commercial kit. A PCR was conducted using primers targeting a fragment of the 18S rRNA gene and the amplicons were purified and sequenced. Of the total Pampas foxes analyzed, 23 (17.6%) had Sarcocystis spp. oocysts/sporocysts in fecal and/or mucosal samples. Sarcocystis spp. sporocysts were detected in 13.0% (17/131) of fecal samples and in 39.4% (13/33) of mucosal samples by the initial sugar flotation. Twenty one L. gymnocercus samples were processed by DNA extraction and PCR. Molecular identification of Sarcocystis spp. infection was successfully achieved in 14 foxes and was distributed as follows: 4.6% S. cruzi (6/131), 3.8% Sarcocystis spp. using birds as IH (S. albifronsi and S. anasi among others, 5/131), 0.8% S. tenella (1/131) and 1.5% (2/131) with low homology (97%) with S. miescheriana. In one fecal sample with spherical oocysts, the sequencing results showed a 100% sequence identity with Hammondia heydorni. The results show that the mucosal scrapings are the eligible sample to identify prevalence and to proceed with species identification. Lycalopex gymnocercus is suggested as definitive host for S. cruzi, S. tenella and probably various Sarcocystis spp. using birds as intermediate hosts as well as for H. heydorni.Facultad de Ciencias VeterinariasConsejo Nacional de Investigaciones Científicas y Técnica

Efficacy of Essential Oils of Thymus vulgaris and Origanum vulgare on Echinococcus granulosus

The aim of the present work was to determine the in vitro effect of T. vulgaris and O. vulgare essential oils against E. granulosus protoscoleces and cysts. Essential oils were added to the medium resulting in thymol final concentrations of 10 μg/mL. The essential oils had a time-dependent effect provoking the complete loss of protoscolex viability after 72 days of postincubation. The results were confirmed at the ultrastructure level. Loss of infectivity in protoscoleces incubated with O. vulgare after 60 days was observed. On the other hand, the weight of cysts recorded in mice inoculated with T. vulgaris treated protoscoleces was significantly lower than that obtained in control group. Gamma-glutamyl-transpeptidase activity was readily detected in the culture supernatant of protoscoleces treated either with the essential oils or thymol. T. vulgaris and O. vulgare essential oils and thymol can induce cell apoptosis of protoscoleces after short incubation times. The efficacy of T. vulgaris and O. vulgare essential oils was also demonstrated in vitro on E. granulosus murine cysts. Our data suggest that essential oils of T. vulgaris and O. vulgare have anthelmintic effect against protoscoleces and cysts of E. granulosus.Fil: Pensel, Patricia Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biologia. Laboratorio de Zoonosis Parasitarias; ArgentinaFil: Maggiore, Marina Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biologia. Laboratorio de Zoonosis Parasitarias; ArgentinaFil: Gende, Liesel Brenda. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología. Laboratorio de Artrópodos; ArgentinaFil: Eguaras, Martin Javier. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología. Laboratorio de Artrópodos; ArgentinaFil: Denegri, Guillermo Maria. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biologia. Laboratorio de Zoonosis Parasitarias; ArgentinaFil: Elissondo, María Celina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biologia. Laboratorio de Zoonosis Parasitarias; Argentin