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Establishing marine species distributions is essential for guiding management and can be estimated by identifying potential favorable habitat at a population level and incorporating individual-level information (e.g., movement constraints) to inform realized space use. In this research, we applied a combined modeling approach to tracking data of adult female and juvenile South American sea lions (Otaria flavescens; n = 9) from July to November 2011 to make habitat predictions for populations in northern Chile. We incorporated topographic and oceanographic predictors with sea lion locations and environmentally based pseudo-absences in a generalized linear model for estimating population-level distribution. For the individual approach, we used a generalized linear mixed-effects model with a negative exponential kernel variable to quantify distance-dependent movement from the colony. Spatial predictions from both approaches were combined in a bivariate color map to identify areas of agreement. We then used a GIS-based risk model to characterize bycatch risk in industrial and artisanal purse-seine fisheries based on fishing set data from scientific observers and artisanal fleet logs (2010-2015), the bivariate sea lion distribution map, and criteria ratings of interaction characteristics. Our results indicate population-level associations with productive, shallow, low slope waters, near to river-mouths, and with high eddy activity. Individual distribution was restricted to shallow slopes and cool waters. Variation between approaches may reflect intrinsic factors restricting use of otherwise favorable habitat; however, sample size was limited, and additional data are needed to establish the full range of individual-level distributions. Our bycatch risk outputs identified highest risk from industrial fisheries operating nearshore (within 5 NM) and risk was lower, overall, for the artisanal fleet. This research demonstrates the potential for integrating potential and realized distribution models within a spatial risk assessment and fills a gap in knowledge on this species' distribution, providing a basis for targeting bycatch mitigation outreach and interventions.
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Scorpions are a group of arthropods that strike fear in many people due to their severe medical symptoms, even death, caused by their venomous stings. Even so, not all scorpion species contain harmful venoms against humans but still have valuable bioactive molecules, which could be used in developing new pharmaceutical leads for treating important diseases. This work conducted a comprehensive analysis of the venom from the scorpion Thorellius intrepidus. The venom of T. intrepidus was separated by size exclusion chromatography, and four main fractions were obtained. Fraction IV (FIV) contained small molecules representing over 90% of the total absorbance at 280 nm. Analysis of fraction FIV by RP-HPLC indicated the presence of three main molecules (FIV.1, FIV.2, and FIV.3) with similar UV absorbance spectra profiles. The molecular masses of FIV.1, FIV.2, and FIV.3 were determined, resulting in 175.99, 190.07, and 218.16 Da, respectively. Further confirmation through 1H-NMR and 13C-NMR analyses revealed that these molecules were serotonin, N-methylserotonin, and bufotenidine. These intriguing compounds are speculated to play a pivotal role in self-defense and increasing venom toxicity and could also offer promising biotechnological applications as small bioactive molecules.
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Picaduras de Escorpión , Venenos de Escorpión , Animales , Humanos , Escorpiones , Ponzoñas , Venenos de Escorpión/químicaRESUMEN
Skin secretions of toads are a complex mixture of molecules. The substances secreted comprise more than 80 different compounds that show diverse pharmacological activities. The compounds secreted through skin pores and parotid glands are of particular interest because they help toads to endure in habitats full of pathogenic microbes, i.e., bacteria, fungi, viruses, and protozoa, due to their content of components such as bufadienolides, alkaloids, and antimicrobial peptides. We carried out an extensive literature review of relevant articles published until November 2022 in ACS Publications, Google Scholar, PubMed, and ScienceDirect. It was centered on research addressing the biological characterization of the compounds identified in the species of genera Atelopus, Bufo, Duttaphrynus, Melanophryniscus, Peltopryne, Phrynoidis, Rhaebo, and Rhinella, with antibacterial, antifungal, antiviral, and antiparasitic activities; as well as studies performed with analogous compounds and skin secretions of toads that also showed these activities. This review shows that the compounds in the secretions of toads could be candidates for new drugs to treat infectious diseases or be used to develop new molecules with better properties from existing ones. Some compounds in this review showed activity against microorganisms of medical interest such as Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Coronavirus varieties, HIV, Trypanosoma cruzi, Leishmania chagasi, Plasmodium falciparum, and against different kinds of fungi that affect plants of economic interest.
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Antiinfecciosos , Bufanólidos , Animales , Bufonidae , Antibacterianos , Bufanólidos/farmacología , Antifúngicos , PielRESUMEN
Mitochondrial introgression raises questions of biogeography and of the extent of reproductive isolation and natural selection. Previous phylogenetic work on the Sorex araneus complex revealed apparent mitonuclear discordance in Iberian shrews, indicating past hybridisation of Sorex granarius and the Carlit chromosomal race of S. araneus, enabling introgression of the S. araneus mitochondrial genome into S. granarius. To further study this, we genetically typed 61 Sorex araneus/coronatus/granarius from localities in Portugal, Spain, France, and Andorra at mitochondrial, autosomal, and sex-linked loci and combined our data with the previously published sequences. Our data are consistent with earlier data indicating that S. coronatus and S. granarius are the most closely related of the three species, confirming that S. granarius from the Central System mountain range in Spain captured the mitochondrial genome from a population of S. araneus. This mitochondrial capture event can be explained by invoking a biogeographical scenario whereby S. araneus was in contact with S. granarius during the Younger Dryas in central Iberia, despite the two species currently having disjunct distributions. We discuss whether selection favoured S. granarius with an introgressed mitochondrial genome. Our data also suggest recent hybridisation and introgression between S. coronatus and S. granarius, as well as between S. araneus and S. coronatus.
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Cromosomas , Musarañas , Animales , Filogenia , Musarañas/genética , Mitocondrias/genética , EspañaRESUMEN
Ciclovía Recreativa is a program in which streets are closed off to automobiles so that people have a safe and inclusive space for recreation and for being physically active. The study aims were: (1) to compare participant's spatial trajectories in four Ciclovía Recreativa programs in Latin America (Bogotá, Mexico City, Santiago de Cali, and Santiago de Chile) according to socioeconomic characteristics and urban segregation of these cities; and (2) to assess the relationship between participants' physical activity (PA) levels and sociodemographic characteristics. We harmonized data of cross-sectional studies including 3282 adults collected between 2015 and 2019. We found the highest mobility for recreation in Bogotá, followed closely by Santiago de Cali. In these two cities, the maximum SES (socioeconomic status) percentile differences between the neighborhood of origin and the neighborhoods visited as part of the Ciclovía use were 33.58 (p-value < 0.001) and 30.38 (p-value < 0.001), respectively, indicating that in these two cities, participants were more likely to visit higher or lower SES neighborhoods than their average SES-of-neighborhood origin. By contrast, participants from Mexico City and Santiago de Chile were more likely to stay in geographic units similar to their average SES-of-origin, having lower overall mobility during leisure time: maximum SES percentile difference 1.55 (p-value < 0.001) and -0.91 (p-value 0.001), respectively. PA levels of participants did not differ by sex or SES. Our results suggest that Ciclovía can be a socially inclusive program in highly unequal and segregated urban environments, which provides a space for PA whilefacilitat physical proximity, exposure to new communities and environments, and interactions between different socioeconomic groups.
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Ejercicio Físico , Inclusión Social , Adulto , Chile , Ciudades , Estudios Transversales , Humanos , América Latina , México , Características de la Residencia , Clase SocialRESUMEN
BACKGROUND: Hip fracture leads to an increase in mortality and deterioration in the quality of life. The increase in life expectancy results in an increase in the number of oldest old patients. AIMS: To analyze the characteristics of centenarian hip fracture patients and compare them with younger hip fracture patients. METHODS: Retrospective study, including 176 patients (48 centenarians, 65 nonagenarians and 63 octogenarians) undergoing surgery after hip from 2009 to 2018 and followed for 1-year survival. Qualitative variables were compared by Chi-square test and quantitative variables, by Kruskal-Wallis test. Survival analysis was performed by Kaplan-Meier test and statistical differences were assessed by log-rank test. p value < 0.05 was considered statistically significant. RESULTS: Centenarians showed the lowest Charlson index (p = 0.001), cognitive impairment (p < 0.001), and daily drug intake (p = 0.034). The in-hospital, 30-day and 1-year mortality rates did not show statistical significant differences. The 1-year survival analysis showed that patients died in order of age (p = 0.045). No differences were found regarding readmissions. DISCUSSION: Hip fracture incidence in centenarians is increasing. Our study states the lowest complexity for centenarians. Hip fracture mortality rates have been linked to patients' age. In-hospital mortality rate has been reduced, and for the 30-day and 1-year mortality rates, we noted that mortality follows a pattern clearly related to age. CONCLUSIONS: Centenarians showed the lowest comorbidity and complexity. Readmissions before 1 year, mortality rates at discharge, 30-day and 1-year follow-up were not significantly different, but 1-year survival analysis showed that patients are dying as they are ageing.
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Fracturas de Cadera , Calidad de Vida , Anciano de 80 o más Años , Fracturas de Cadera/epidemiología , Fracturas de Cadera/cirugía , Humanos , Estimación de Kaplan-Meier , Estudios Retrospectivos , Análisis de SupervivenciaAsunto(s)
Nefrostomía Percutánea/métodos , Obstrucción Ureteral/terapia , Adulto , Anciano , Catéteres , Constricción Patológica , Diseño de Equipo , Femenino , Humanos , Masculino , Persona de Mediana Edad , Nefrostomía Percutánea/instrumentación , Radiografía Intervencional , Resultado del Tratamiento , Obstrucción Ureteral/diagnóstico por imagenRESUMEN
The high degree of endemism on Sulawesi has previously been suggested to have vicariant origins, dating back to 40 Ma. Recent studies, however, suggest that much of Sulawesi's fauna assembled over the last 15 Myr. Here, we test the hypothesis that more recent uplift of previously submerged portions of land on Sulawesi promoted diversification and that much of its faunal assemblage is much younger than the island itself. To do so, we combined palaeogeographical reconstructions with genetic and morphometric datasets derived from Sulawesi's three largest mammals: the babirusa, anoa and Sulawesi warty pig. Our results indicate that although these species most likely colonized the area that is now Sulawesi at different times (14 Ma to 2-3 Ma), they experienced an almost synchronous expansion from the central part of the island. Geological reconstructions indicate that this area was above sea level for most of the last 4 Myr, unlike most parts of the island. We conclude that emergence of land on Sulawesi (approx. 1-2 Myr) may have allowed species to expand synchronously. Altogether, our results indicate that the establishment of the highly endemic faunal assemblage on Sulawesi was driven by geological events over the last few million years.
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Búfalos/clasificación , Especiación Genética , Fenómenos Geológicos , Porcinos/clasificación , Animales , Secuencia de Bases , Búfalos/genética , ADN Mitocondrial , Geografía , Indonesia , Islas , Repeticiones de Microsatélite , Filogenia , Filogeografía , Porcinos/genéticaRESUMEN
Questions surrounding the chronology, place, and character of the initial human colonization of the Americas are a long-standing focus of debate. Interdisciplinary debate continues over the timing of entry, the rapidity and direction of dispersion, the variety of human responses to diverse habitats, the criteria for evaluating the validity of early sites, and the differences and similarities between colonization in North and South America. Despite recent advances in our understanding of these issues, archaeology still faces challenges in defining interdisciplinary research problems, assessing the reliability of the data, and applying new interpretative models. As the debates and challenges continue, new studies take place and previous research reexamined. Here we discuss recent exploratory excavation at and interdisciplinary data from the Monte Verde area in Chile to further our understanding of the first peopling of the Americas. New evidence of stone artifacts, faunal remains, and burned areas suggests discrete horizons of ephemeral human activity in a sandur plain setting radiocarbon and luminescence dated between at least ~18,500 and 14,500 cal BP. Based on multiple lines of evidence, including sedimentary proxies and artifact analysis, we present the probable anthropogenic origins and wider implications of this evidence. In a non-glacial cold climate environment of the south-central Andes, which is challenging for human occupation and for the preservation of hunter-gatherer sites, these horizons provide insight into an earlier context of late Pleistocene human behavior in northern Patagonia.
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Arqueología , Migración Humana , Paleontología , Carbono , Chile , Cultura , Humanos , RadioisótoposRESUMEN
We report a 25 year old mole admitted to a critical care unit for fever, lung opacities and acute respiratory failure. A chest angio-CAT sean showed multiple pulmonary artery aneurysms. A deep venous thrombosis of both lower limbs was also documented. A Hughes-Stovin syndrome was postulated. An inferior vena cava filter was placed. The patient received antimicrobial therapy subsiding fever and respiratory failure. Subsequently, he was treated with intravenous and oral steroids and one dose of cyclophosphamide. The patient was discharged in good conditions fifteen days after admission.
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Aneurisma/diagnóstico , Arteria Pulmonar , Trombosis de la Vena/diagnóstico , Adulto , Aneurisma/terapia , Chile , Humanos , Síndrome , Tomografía Computarizada por Rayos X , Trombosis de la Vena/terapiaRESUMEN
We report a 25yearold mole admitted to a critical care unit for fever, lung opacities and acute respiratory failure. A chest angio-CAT sean showed multiple pulmonary artery aneurysms. A deep venous thrombosis of both lower limbs was also documented. A Hughes-Stovin syndrome was postulated. An inferior vena cava filter was placed. The patient received antimicrobial therapy subsiding fever and respiratory failure. Subsequently, he was treated with intravenous and oral steroids and one dose of cyclophosphamide. The patient was discharged in good conditions fifteen days after admission.
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Adulto , Humanos , Aneurisma/diagnóstico , Arteria Pulmonar , Trombosis de la Vena/diagnóstico , Aneurisma/terapia , Chile , Síndrome , Tomografía Computarizada por Rayos X , Trombosis de la Vena/terapiaRESUMEN
We investigated the effect of the parasitic mite Varroa destructor on the immunological and nutritional condition of honey bees, Apis mellifera, from the perspective of the individual bee and the colony. Pupae, newly-emerged adults and foraging adults were sampled from honey bee colonies at one site in S. Texas, USA. Varroainfested bees displayed elevated titer of Deformed Wing Virus (DWV), suggestive of depressed capacity to limit viral replication. Expression of genes coding three anti-microbial peptides (defensin1, abaecin, hymenoptaecin) was either not significantly different between Varroa-infested and uninfested bees or was significantly elevated in Varroa-infested bees, varying with sampling date and bee developmental age. The effect of Varroa on nutritional indices of the bees was complex, with protein, triglyceride, glycogen and sugar levels strongly influenced by life-stage of the bee and individual colony. Protein content was depressed and free amino acid content elevated in Varroa-infested pupae, suggesting that protein synthesis, and consequently growth, may be limited in these insects. No simple relationship between the values of nutritional and immune-related indices was observed, and colony-scale effects were indicated by the reduced weight of pupae in colonies with high Varroa abundance, irrespective of whether the individual pupa bore Varroa.
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Se presenta el caso clínico de una paciente de 30 años, con diagnóstico de VIH + desde el año 2000, en terapia antirretroviral desde el año 2004. Desde el año 2007 con disnea de esfuerzo progresiva, que en el último año se hace severa, asociada a astenia, fatigabilidad y edema vespertino de extremidades inferiores. El ecocardiograma detecta un aumento de la presión de arteria pulmonar, lo que se confirma a través de un cateterismo cardíaco derecho. Se descarta tromboembolismo pulmonar y se concluye como una HAP secundaria a VIH. La hipertensión arterial pulmonar (HAP) es una enfermedad de baja frecuencia y se puede asociar a infección por virus de la inmunodeficiencia humana (VIH), presentando una prevalencia 6 a 12 veces mayor en relación a individuos sin infección por VIH. La HAP es independiente del recuento de linfocitos T CD4 y en su patogenia participan proteínas virales, como la glicoproteína 120 y las proteínas Nef y Tat, que estimulan una cascada inflamatoria sistémica, induciendo angiogénesis en los vasos pulmonares. El estudio hemodinámico a través de cateterismo derecho es el método de elección para la confirmación diagnóstica.
We report the case of a patient 30 years, diagnosed with human immunodeficiency virus (HIV) since 2000, on antiretroviral therapy since 2004. Since 2007 with progressive dyspnea, which in the past year becomes severe, associated with asthenia, fatigue and edema of lower limbs evening. Echocardiography detects an increase in pulmonary artery pressure, which is confirmed by a right heart catheterization. Pulmonary embolism is ruled out and concludes as a pulmonary arterial hypertension (PAH) secondary to HIV. Pulmonary arterial hypertension is a disease of low frequency and can be associated with infection by HIV, with prevalence 6 to 12 times greater relative to individuals without HIV infection. PAH is independent of CD4 T lymphocyte count and viral proteins involved pathogenesis, such as glycoprotein 120 and Nef and Tat proteins, which stimulate a systemic inflammatory cascade, inducing angiogenesis in the pulmonary vessels. The hemodynamic study through right heart catheteri-zation is the method of choice for diagnostic confirmation.
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Humanos , Adulto , Femenino , Hipertensión Pulmonar/diagnóstico , Hipertensión Pulmonar/etiología , Infecciones por VIH/complicacionesRESUMEN
BACKGROUND: Exposure to solar activity may be associated with incidence of depressive and manic disorders. AIM: To assess the link between solar activity and appearance of affective disorders. MATERIAL AND METHODS: We examined 1862 clinical records of a psychiatric clinic located in Santiago, Chile. Patients with major depression and manic disorders were included in the study, only when they were admitted at the clinic for the first time. Solar activity was calculated using the Wolf number, which is given by the formula R = K(10g+f), where "g" stands for the groups of sunspots and "f" is the total number of sunspots. We examined the correlation between annual incidence of hospital admissions and average Wolf numbers for the period 1990-2005, which corresponds to approximately one and half solar cycles of 16 years. RESULTS: A total of 450 medical records corresponding to 299 patients (199 women) with depressive symptoms and 151 patients (73 women) with mania, were analyzed. There was a higher number of admissions for depression during the years with lower solar activity. Admissions due to mania tended to increase in the years with high solar activity. There was a negative correlation between the number of hospital admissions due to depression and solar activity (Spearman r = -0.812, p < 0.01). The association between the latter parameter and admissions due to mania did not reach statistical significance. CONCLUSIONS: There is a significant negative association between the rate of hospital admissions due to depressive disorders and solar activity.
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Trastorno Bipolar/epidemiología , Trastorno Depresivo/epidemiología , Hospitalización/estadística & datos numéricos , Actividad Solar , Adolescente , Adulto , Anciano , Chile/epidemiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Trastornos del Humor/epidemiología , Adulto JovenRESUMEN
Background: Exposure to solar activity may be associated with incidence of depressive and manic disorders. Aim: To assess the link between solar activity and appearance of affective disorders. Material and Methods: We examined 1862 clinical records of a psychiatric clinic located in Santiago, Chile. Patients with major depression and manic disorders were included in the study, only when they were admitted at the clinic for the first time. Solar activity was calculated using the Wolf number, which is given by the formula R= K(10g+f), where g stands for the groups of sunspots and f is the total number of sunspots. We examined the correlation between annual incidence of hospital admissions and average Wolf numbers for the period 1990-2005, which corresponds to approximately one and half solar cycles of 16 years. Results: A total of 450 medical records corresponding to 299 patients (199 women) with depressive symptoms and 151 patients (73 women) with mania, were analyzed. There was a higher number of admissions for depression during the years with lower solar activity. Admissions due to mania tended to increase in the years with high solar activity. There was a negative correlation between the number of hospital admissions due to depression and solar activity (Spearman r =-0.812, p < 0.01). The association between the latter parameter and admissions due to mania did not reach statistical significance. Conclusions: There is a significant negative association between the rate of hospital admissions due to depressive disorders and solar activity.
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Adolescente , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Adulto Joven , Trastorno Bipolar/epidemiología , Trastorno Depresivo/epidemiología , Hospitalización/estadística & datos numéricos , Actividad Solar , Chile/epidemiología , Trastornos del Humor/epidemiologíaRESUMEN
This study was designed to explore if each individual case of naturally acquired porcine cysticercosis, living in different geographic rural areas of central Mexico, is caused by one or more different specimens of Taenia solium tapeworm. The genetic variability among cysticerci from the same pig and that from different pigs was assessed by random amplified polymorphic DNA markers (RAPDs), through the percentage of polymorphic loci, the number of effective alleles, the expected heterozygosity and the Shannon index. The parasite population's reproductive structure was estimated through the association index (I(A)), and the degree of genetic differentiation and variation was determined using AMOVA. Using six different random primers, and a total of 181 cysticerci from 14 pigs, 88 different loci were amplified: 85% were polymorphic between pigs and 24% within pigs. The phenogram grouped the cysticerci into eight major clusters, with differences in the genetic distances among all cysticerci from 14 pigs ranging from 0.78 to 1. Most of the cysticerci grouped in accord with their different geographical origin and with their pig of origin. The similarity matrix produced from the phenogram (obtained by UPGMA) and the original similarity matrix yielded a good cophenetic correlation (r=0.82317, P=0.0004), which suggests that the phenogram accurately represents the original genetic similarities between isolates. The combination of I(A) (0.0-0.089) with the genetic diversity index (0.009-0.073) supports the idea that DNA diversity in T. solium cysticerci of naturally infected pigs is within the range expected from a recombination process occurring during sexual reproduction. The small genetic diversity found within the cysticerci of each pig (33.81%), when compared with that between pigs (66.19%), indicates that pigs are rarely infected by different tapeworms. It would then appear that porcine cysticercosis courses with effective concomitant immunity, as occurs in ovine cysticercosis.
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Cisticercosis/veterinaria , Variación Genética , Enfermedades de los Porcinos/parasitología , Taenia solium/genética , Animales , Cisticercosis/parasitología , Cysticercus/genética , México , Filogenia , Polimorfismo Genético/genética , Porcinos , Taenia solium/clasificaciónRESUMEN
Taenia solium is a cestode parasitic of humans and pigs that strongly impacts on public health in developing countries. Its larvae (cysticercus) lodge in the brain, causing neurocysticercosis, and in other tissues, like skeletal muscle and subcutaneous space, causing extraneuronal cysticercosis. Prevalences of these two clinical manifestations vary greatly among continents. Also, neurocysticercosis may be clinically heterogeneous, ranging from asymptomatic forms to severely incapacitating and even fatal presentation. Further, vaccine design and diagnosis technology have met with difficulties in sensitivity, specificity and reproducibility. Parasite diversity underlying clinical heterogeneity and technological difficulties is little explored. Here, T. solium genetic population structure and diversity was studied by way of random amplified polymorphic DNA in individual cysticerci collected from pigs in Madagascar and two regions in Mexico. The amplification profiles of T. solium were also compared with those of the murine cysticercus Taenia crassiceps (ORF strain). We show significant genetic differentiation between Madagascar and Mexico and between regions in Mexico, but less so between cysticerci from different localities in Mexico and none between cysticerci from different tissues from the same pig. We also found restricted genetic variability within populations and gene flow was estimated to be low between populations. Thus, genetic differentiation of T. solium suggests that different evolutionary paths have been taken and provides support for its involvement in the differential tissue distribution of cysticerci and varying degrees of severity of the disease. It may also explain difficulties in the development of vaccines and tools for immunodiagnosis.
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Cisticercosis/veterinaria , ADN de Helmintos/análisis , Países en Desarrollo , Variación Genética , Enfermedades de los Porcinos/parasitología , Taenia solium/genética , Animales , Encéfalo/parasitología , Cisticercosis/parasitología , Madagascar , México , Músculos/parasitología , Proyectos Piloto , Prevalencia , Porcinos/parasitologíaRESUMEN
Se desarrolló un sistema computarizado que permite amplificar la señal del ECG, digitalizarla, promediarla, filtrarla digitalmente, analizar la primera derivada y analizarla a través de la Transformación de Fourier. Tal sistema es capaz de detectar potenciales retrasados que se originan en áreas del miocardio alterando morfológicamente que condicionan altraciones en la velocidad de conducción. Para validar el sistema, se realizaron 28 estudios que correspondieron a 15 sujetos normales (Grupo 1), 10 en pacientes con infarto del miocardio tanto antiguo como reciente (Grupo 2) y 3 en pacientes con infarto del miocardio y taquicardia ventricular sostenida, documentada en la unidad coronaria o en electrocardiografía ambulatoria. De las 31 variables obtenidas del análisis en tiempo, primera derivada y análisis en frecuencia, el voltaje RMS de los 40 mseg terminales del QRS filtrado a 25 HZ, los cruces por la línea de base de la derivada de la deriación Y y el voltaje RMS de la transformada de Fourier de los 40 mseg terminales de 3.9 a 304.7 Hz, permitieron diferenciar a los pacientes del Grupo 3 de aquellos del Grupo 1 (p<0.0001). Por otra parte, el valor RMS de la derivada de la derivación Y, la amplitud pico-pico de la derivada de la derivación Z y el valor RMS de la derivada de esta derivación permiteiron diferenciar al Grupo 3 del Grupo 2 (p<0.002). Se concluye que el análisis de la primera derivada, el análisis en frecuencia y el análisis en tiempos son, en ese orden, útiles en la identificación de potenciales retrasados en la porción terminal del QRS.