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Ongoing climate change threatens the biodiversity of glacier-fed river ecosystems worldwide through shifts in water availability and timing, temperature, chemistry, and channel stability. However, tropical glacier-fed rivers have received little attention compared to those in temperate and Arctic biomes, despite their unique biodiversity potentially responding differently due to additional stress from higher altitude locations thus lower oxygen availability, diurnal freeze-thaw cycles, and annual monsoon rainfall disturbances. However, tropical glacier-fed rivers have received little attention compared to those in temperate and Arctic biomes, despite their unique biodiversity potentially responding differently due to additional stress from higher altitude locations thus lower oxygen availability, diurnal freeze-thaw cycles, and annual monsoon rainfall disturbances. This study quantified aquatic biodiversity responses to decreasing glacier cover in the Cordillera Blanca range of the Peruvian Andes. Ten rivers were studied along a gradient of decreasing glacier cover in the Parón, Huaytapallana, and Llanganuco basins, with a specific focus on macroinvertebrates and physicochemical parameters in both the dry and wet seasons. We found higher temperatures, more stable and lower turbidity rivers as glacier cover decreased, which were related significantly to higher local diversity and lower ß-diversity. Analysis of similarity revealed significant differences in the macroinvertebrate community among rivers with high, medium, or low glacier cover, illustrating turnover from specialists to generalists as glacial influence decreased. Redundancy analysis demonstrated that there were more species found to prefer stable beds and water temperatures in medium and low glacier cover in a catchment rivers. However, certain taxa in groups such as Paraheptagyia, Orthocladiinae, Anomalocosmoecus, and Limonia may be adapted to high glacial influence habitats and at risk of glacier retreat. Although species composition was different to other biomes, the Cordillera Blanca rivers showed similar benthic macroinvertebrate biodiversity responses to glacier retreat, supporting the hypothesis that climate change will have predictable effects on aquatic biodiversity in mountain ranges worldwide.
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Biodiversidad , Cubierta de Hielo , Invertebrados , Ríos , Animales , Invertebrados/fisiología , Cambio Climático , Estaciones del Año , TemperaturaRESUMEN
Background: Segmental surgical resection is a frequently indicated procedure to treat aggressive mandibular tumors. One of the most important complications derived from this technique is permanent paresthesia of the inferior alveolar nerve (IAN), which significantly affects the quality of life of patients who experience it. This could be avoided through maneuvers that preserve the IAN. The objective of this paper is to review the main techniques for IAN preservation and to present 2 cases with the technique used by the author. Material and Methods: A systematic review was performed according to the PRISMA guidelines, apropos of two clinical cases reported in this study. The MEDLINE/PubMed and Scopus databases were searched. Several variables were considered and are presented in detail in the form of tables and figures. In addition, 2 case reports with NAI preservation techniques are presented. Results: 13 articles were finally obtained for analysis. 127 patients were evaluated, reporting mandibular resections associated with various pathologies. Various surgical techniques were used, all with the same goal of maintaining the IAN. In most of the patients, the maintenance of sensitivity was achieved, which was verified with different methods. Conclusions: Preservation of the IAN in maxillofacial surgical procedures where surgical resection of the mandibular bone has been performed is an alternative that has demonstrated successful results in terms of reducing postoperative sequelae and is currently positioned as a necessary and feasible procedure. (AU)
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Humanos , Traumatismos Mandibulares , Neoplasias , Parestesia , Nervio Mandibular , Calidad de Vida , Patología Bucal , Cirugía BucalRESUMEN
BACKGROUND: Planning surgical procedures of the lower leg benefits from considering the possibility of an aberrant anterior tibial artery (AATA), but previously published data on the frequency of this anatomic variant shows heterogeneity. We assessed the prevalence of AATA in a Latin American cohort using magnetic resonance imaging (MRI) and compared these with other studies reported in the literature. METHODS: We retrospectively included consecutive patients who had undergone multiplanar knee MRI at a radiology department in Lima, Peru. The MRI protocol included coronal T1 weighted, axial, sagittal and coronal proton density fat-saturated (PDFS) and sagittal T2 weighted images. Two experienced radiologists assessed all images and were blinded to each other's findings. The frequency of the AATA was compared to previous cohorts. A scoping review was undertaken to provide an overview of previously published data on the prevalence of ATAA. RESULTS: We analyzed 280 knee MRI examinations of 253 patients (median age 41 years (IQR 31-52), 53.8% male). The aberrant anterior tibial artery variant was present in 8 of 280 (2.9%) evaluated knees, resulting in a prevalence of 3.2% in our study population. The PDFS sequence in the axial or sagittal orientation was most effective to identify AATA. The frequency of AATA in the reviewed literature using different radiological modalities ranged from 0.4 to 6% (median 1%, IQR (0.5-2.3%). CONCLUSIONS: The AATA is a frequent vascular variant that can be detected by MRI in the preparation of invasive interventions of the lower leg.
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Imagen por Resonancia Magnética , Arterias Tibiales , Adulto , Femenino , Humanos , Articulación de la Rodilla , Masculino , Prevalencia , Estudios RetrospectivosRESUMEN
Abrupt warming events recorded in Greenland ice cores known as Dansgaard-Oeschger (DO) interstadials are linked to changes in tropical circulation during the last glacial cycle. Corresponding variations in South American summer monsoon (SASM) strength are documented, most commonly, in isotopic records from speleothems, but less is known about how these changes affected precipitation and Andean glacier mass balance. Here we present a sediment record spanning the last ~50 ka from Lake Junín (Peru) in the tropical Andes that has sufficient chronologic precision to document abrupt climatic events on a centennial-millennial time scale. DO events involved the near-complete disappearance of glaciers below 4700 masl in the eastern Andean cordillera and major reductions in the level of Peru's second largest lake. Our results reveal the magnitude of the hydroclimatic disruptions in the highest reaches of the Amazon Basin that were caused by a weakening of the SASM during abrupt arctic warming. Accentuated warming in the Arctic could lead to significant reductions in the precipitation-evaporation balance of the southern tropical Andes with deleterious effects on this densely populated region of South America.
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An amendment to this paper has been published and can be accessed via a link at the top of the paper.
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Pre-Hispanic artifacts and sacred architecture were recently discovered submerged in a large lake (Laguna Sibinacocha) in the Peruvian Andes. The underwater ruins indicate a dramatic shift in the region's hydrology but the timing and triggers of this shift remain unknown. In a novel approach blending archaeology and paleoecology, we analyzed a sediment sequence from within one of the recovered artifacts, specifically a pot from the Late Intermediate Period (~1000-1400 CE). Radioisotopic dating of discrete sediment intervals sampled from the pot show a stratigraphically intact profile that preserves a history of change at this site. The pot's basal sediment age places the timing of lake-level rise at ~1600 CE, which post-dates the end of the Inca Empire (1400-1532 CE) by several decades. The ubiquity of planktonic algae throughout the sediment profile suggests water levels remained high above the pot since its submergence. Paleoclimate data from the nearby Quelccaya ice core records indicate lake flooding followed a pronounced wet period beginning ~1520 CE. These data show the permanence of mean state changes in climate on the region's hydrology, with clear implications for the study site (an important water resource for ~500,000 people) and other lakes in the rapidly warming Andes.
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BACKGROUND: Among patients with coronary artery disease (CAD), 80%-90% present at least one conventional risk factor. On the other hand, lipid profile modification after a cardiovascular event related to acute coronary syndrome (ACS) has been recognized. The prevalence of conventional risk factors and the lipid profile at the time of admission in patients with ACS and significant CAD (stenosis ≥50%) determined through coronary angiography is not well described. METHODS: We studied 3,447 patients with a diagnosis of ACS and significant CAD with stenosis ≥50%, as shown o n angiography. We recorded the presence of conventional risk factors, including smoking, hypertension, dyslipidemia, and diabetes. In addition, we analyzed the lipid profiles within the first 24 hours of admission. We analyzed the studied population and compared findings according to sex. RESULTS: Most patients (81.7%) were male. ST-elevation myocardial infarction was present in 51.3% of patients, and non-ST-elevation acute coronary syndrome was present in 48.7%. The most frequent risk factor was smoking, which was present in 68% of patients, followed by hypertension (57.8%), dyslipidemia (47.5%), and diabetes (37.7%). In women, the most frequent risk factors were hypertension, diabetes, and dyslipidemia, whereas in men, smoking was the most frequent. We identified at least one risk factor in 95.7% of all patients, two or three risk factors in 62%, and four risk factors in 8.6% of patients. The lipid profile analysis revealed that 85.1% of patients had some type of dyslipidemia, and the most frequent was low levels of high-density lipoprotein cholesterol (68.6% of cases). CONCLUSION: We found at least one conventional risk factor in 95.7% of patients with ACS and significant CAD. The lipid profile analysis revealed that two thirds of cases had low high-density lipoprotein cholesterol levels.
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Mercury (Hg) is a toxic metal that is transported globally through the atmosphere. The emission of Hg from mineral reservoirs and subsequent recycling in surface reservoirs (i.e., soil/biomass, ocean, and atmosphere) are fundamental to the modern global Hg cycle, yet past emissions from anthropogenic and natural sources are not fully constrained. We use a sediment core from Yanacocha, a headwater lake in southeastern Peru, to study the anthropogenic and natural controls on atmospheric Hg deposition during the Holocene. From 12.3 to 3.5 ka, Hg fluxes in the record are relatively constant (mean ± 1σ: 1.4 ± 0.6 µg m-2 a-1, n = 189). Past Hg deposition does not correlate with changes in regional temperature and precipitation, inferred from nearby paleoclimate records, or with most large volcanic events that occurred regionally, in the Andean Central Volcanic Zone (~300-400 km from Yanacocha), and globally. In B.C. 1450 (3.4 ka), Hg fluxes abruptly increased and reached the Holocene-maximum flux (6.7 µg m-2 a-1) in B.C. 1200, concurrent with a ~100-year peak in Fe and chalcophile metals (As, Ag, Tl) and the presence of framboidal pyrite. Continuously elevated Hg fluxes from B.C. 1200-500 suggest a protracted mining-dust source near Yanacocha that is identical in timing to documented pre-Incan cinnabar mining in central Peru. During Incan and Colonial time (A.D. 1450-1650), Hg deposition remains elevated relative to background levels but lower relative to other Hg records from sediment cores in central Peru, indicating a limited spatial extent of preindustrial Hg emissions. Hg fluxes from A.D. 1980 to 2011 (4.0 ± 1.0 µg m-2 a-1, n = 5) are 3.0 ± 1.5 times greater than pre-anthropogenic fluxes and are similar to modern fluxes documented in remote lakes around the world.
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Introducción: Se incluyen 55 pacientes con el diagnóstico de hepatocarcinoma para determinar los factores asociados a mortalidad. Método: Se realizó un estudio de tipo descriptivo, retrospectivo y corte transversal, mediante la revisión documental de historias clínicas del Hospital Nacional del Sur Carlos Alberto Seguín Escobedo EsSalud entre los años 2000 a 2004. Resultados: Se encontró que de los 55 pacientes fallecieron el 47.27 por ciento, con una predominancia para el sexo masculino 69.29 por ciento, y en edades entre los 60 y 80 años. Los factores de riesgo asociados a diagnóstico de hepatocarcinoma incluyeron principalmente el antecedente de consumo de alcohol, de anticonceptivos orales en mujeres, el de paracetamol, en general, y en menor porcentaje por infección crónica por virus hepatotrofos. Conclusiones: El hepatocarcinoma afectó más a varones (69,09 por ciento) que a mujeres (30,91 por ciento), diferencia que resulta ser estadísticamente significativa (p menor que 0,01). La edad de afectación fue bastante variable, alcanzando a niños de 2 años y hasta ancianos de 93 años. El síntoma principal es dolor en hipocondrio derecho. Al examen físico masa palpable en cuadrante superior derecho 52.72 por ciento.
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Masculino , Femenino , Humanos , Persona de Mediana Edad , Anciano , Anciano de 80 o más Años , Carcinoma Hepatocelular , Factores de Riesgo , Hepatitis , Mortalidad , Neoplasias Hepáticas , Epidemiología Descriptiva , Estudios Retrospectivos , Estudios TransversalesRESUMEN
INTRODUCTION: The cystic tumor of the pancreas is a relatively uncommon entity. There are different types of pancreatic cystic tumors and they all exhibit different degrees of malignancy. These tumors represent 1% of all primary pancreatic tumors and only 15% of the cystic lesions. The serous cystadenomas (SCA) are mostly benign lesions with an average size of 4 cm; nevertheless, in some rare cases these are giant lesions, generally larger than 15 cm. Sometimes these tumors produce a symptomatology caused by the compression of neighboring structures, therefore they are generally operable. MATERIAL AND METHOD: During the period from June 2004 to June 2005, the 3A II unit of the Edgardo Rebagliati Martins Hospital operated on two cases of giant serous cystadenomas of the pancreas, one located in the tail of the pancreas and the other in the head of the pancreas, with an average size of 16 cm. DISCUSSION: The giant SCAs of the pancreas are rarely seen lesions that, according to different authors, are usually larger than 10 to 15 cm. in diameter. These lesions do not represent a diagnosis problem and are generally operable since they produce a symptomatology by compression. The surgical resection can be complicated due to their large size and to the considerable neovascularization.
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Cistadenoma Seroso/cirugía , Neoplasias Pancreáticas/cirugía , Anciano , Anciano de 80 o más Años , Cistadenoma Seroso/patología , Femenino , Humanos , Masculino , Neoplasias Pancreáticas/patologíaRESUMEN
Introducción: Los tumores quísticos del páncreas son una entidad poco común que reúnen a distintas variedades. Las cuales presentan diferentes grados de malignidad. Estos representan el 1 por ciento de todos los tumores primarios del páncreas y solo el 15 por ciento de las lesiones quísticas. Los cistoadenomas serosos (SCA) son lesiones casi siempre benignas con un tamaño promedio de 4 cm sin embargo en muy raros casos existen lesiones gigantes generalmente mayores de 15 cm, estos tumores algunas veces producen una sintomatología causada por la comprensión de estructuras vecinas por lo que generalmente son quirúrgicos. Material y método: Durante el periodo comprendido entre Junio del 2004 a Junio del 2005 se operaron en el servicio 3A II del Hospital Edgardo Rebagliati Martins dos casos de cistoadenomas serosos gigantes del páncreas uno localizado en la cola del páncreas y otro en la cabeza con un tamaño promedio de 16 cm. Discusión: Los SCA gigantes del páncreas son lesiones muy poco frecuentes generalmente mayores de 10 a 15 cm. de diámetro de acuerdo a los diferentes autores, estas lesiones no presentan un problema diagnóstico, siendo generalmente quirúrgicas ya que producen sintomatología por comprensión. La resección quirúrgica puede ser complicada debido al gran tamaño y a la neovascularización importante que presentan.
Introduction: The cystic tumor of the pancreas is a relatively uncommon entity. There are different types of pancreatic cystic tumors and they all exhibit different degrees of malignancy.These tumors represent 1 per cent of all primary pancreatic tumors and only 15 per cent of the cystic lesions. The serous cystadenomas (SCA) are mostly benign lesions with an average size of 4 cm; nevertheless, in some rare cases these are giant lesions, generally larger than 15 cm. Sometimes these tumors produce a symptomatology caused by the compression of neighboring structures, therefore they are generally operable.MATERIAL AND METHOD: During the period from June 2004 to June 2005, the 3A II unit of the Edgardo RebagliatiMartins Hospital operated on two cases of giant serous cystadenomas of the pancreas, one located in the tail of the pancreas and the other in the head of the pancreas, with an average size of 16 cm. DISCUSSION: The giant SCAs of the pancreas are rarely seen lesions that, according to different authors, are usually larger than 10 to 15 cm. in diameter. These lesions do not representa diagnosis problem and are generally operable since they produce a symptomatology by compression. The surgical resection can be complicated due to their large size and to the considerable neovascularization.
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Humanos , Masculino , Anciano de 80 o más Años , Anciano , Femenino , Adenoma , Neoplasias Pancreáticas/cirugía , Quiste Pancreático/cirugía , Quiste PancreáticoRESUMEN
Presentamos el caso de un varón de 50 años con infarto agudo demiocardio sin factores comunes de riesgo coronario (Dislipidemia,Hipertensión, Síndrome Metabólico), con excepción del hábitota baquico. Que ingresó con un cuadro clínico, electrocardiográfico yenzimático de infarto agudo de miocardio. Se efectuó coronariografía con la intención de Angioplastía y/o Stent, y se encontraron lesiones coronarias mínimas. En consecuencia, solamente se indicó tratamiento médico. Se discuten los mecanismos del infarto en estepaciente...
A 50-year old man was evaluated in the cardiac clinic of the Instituto Nacional de Tórax, with myocardial infarction without common risk factors (like Dyslipidemia, Hypertension, Metabolic Syndrome), except the tobacco inhalation. He was admitted incardiac ward with the diagnosis of myocardial infarction by meansof electrocardiography, and enzimatic changes. After a few days acoronary angiography was performed with the objective of and stent implantation and there was found slight coronary lesions. There fore,he received only medical treatment. We discuss the pathophysiology of the myocardial infarction in this patient.
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Humanos , Masculino , Persona de Mediana Edad , Isquemia Miocárdica/complicaciones , Isquemia Miocárdica/diagnóstico , Vasos Coronarios/fisiopatología , Ecocardiografía , Electrocardiografía/métodosRESUMEN
El presente articulo pretende actualizar las indicaciones y las características técnicas básicas de los principales tipos de marcapasos, a propósito de la experiencia en el implante de los mismos. Con este fin se revisaron los expedientes de implantes de marcapasos elfectuados en el periodo Julio de 1996 a junio del 2003, en el Instituto Nacioal de Tórax. Se hace especial énfasis en la técnica quirúrgica. Las indicaciones más frecuentes para implante de marcapasos en la serie estudiada fueron la cardioesclerosis (61 porciento) y la cardiopatía chagásica (33 por ciento). La alteraión electrocardiográfica principal pre-implante fue el bloqueo auriculoventriclar completo /57 por ciento). La técnica habitual consistió en la disección venosa. La gran mayoría de los marcapsos implantados fueron del tipo VVI (86 por ciento). Los resultados son buenos con un mínimo índice de complicaciones.
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Humanos , Masculino , Adolescente , Adulto , Femenino , Marcapaso Artificial , Estimulación Cardíaca Artificial/métodos , Estimulación Cardíaca Artificial/normas , Estimulación Eléctrica/instrumentación , Estimulación Eléctrica/métodos , CardiologíaRESUMEN
La investigación se realizó, utilizando las fuentes de información secundaria disponibles en los servicios pertinentes del departamento de cardiología del Instituto Nacional del Tórax. Se concideró que unestudio de estas características es necesario por que busca mejorar la demanda de servicios, facilitando en ecceso de las personas de bajos y medianos recursos que acuden al hospital público. La plena disponibilidad de la información aseguró la facilidad de la investigación. L a investigación es tracendente porque permitirá aplicar actividades gerenciales futuras, de sostenibilidad técnica y financiera para el acceso de los usuarios. Se trata también de un estudio de actualidad, considerando que la atención Médica gerenciada, es untema de discusión y de aplicación en América Latina por sus aplicaciones técnicas y sobre todo ideológicas.
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Cardiología , Atención Médica , Métodos , BoliviaRESUMEN
En los hospitales de la ciudad de La Paz, se asume que los tiempos de espera de los pacientes, son demasiados prolongados, existiendo pocas referencias al respecto. Aún cuando en teoría, todos los hospitales de tercer nivel tendrían la misma demanda, el Instituto Nacional de Oftalmología se caracteriza por una elevada demanda, aproximadamente de 2400 pacientes por mes, aspecto que influye directamente en la demora en los tiempos de espera. El objetivo de la presente propuesta de intervención es determinar si aplicando estrategias en las áreas de planificación, organización y desempeño de recursos humanos, se reducirá el tiempo de tránsito de los usuarios en la consulta externa del Instituto Nacional de Oftalmología, un objetivo de mas largo alcance, que no compete a la presente intervención consistirá en sugerir a las instancias directivas del Ministerio de Salud Pública y Previsión Social organizar la demanda por niveles de atención de salud y de acuerdo a la complejidad de la nosología. La hipotesis de la propuesta expresa "que se disminuirá la prolongación del tiempo de tránsito mejorando las áreas de planificación, organización y desempeño de los recursos humanos de la consulta externa del Instituo Nacional de Oftalmología". El alcance de la información a obtenerse podría servir como marco de referencia a otros centros hospitalarios, considerando su magnitud, trascendencia y pertinencia. La intervención contará con accesibilidad a la información y con el apoyo de las autoridades del Instituto Nacional de Oftalmología
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Objetivo: Iniciar en nuestro medio el estudio del síncope recurrente de origen no determinado empleando la Prueba de Inclinación (PI) sensibilizada con dinitrato de isosorbide (ISB). Material y Métodos: Estudio prospectivo de pacientes con síncope recurrente, set. 1995 - set. 1996, en el Centro Médico Naval, utilizando la PI (80º por 25 min). Si la prueba resultaba negativa, se repetía pero con ISB 5 mg SL. Se realizó el mismo protocolo a paciente sin antecedentes de síncope. Resultados: Se estudió 23 pacientes. En la prueba basal, 4 (17 por ciento) tuvieron resultado positivo; a los 19 (83 por ciento) negativos se les estimuló con ISB 5 mg SL: 10 pacientes dieron respuesta positiva (43 por ciento del total). Sólo un paciente presentó efecto colateral (cefalea intensa). Sólo un sujeto control (8 por ciento) tuvo PI (+) luego de la administración de ISB. La mayoría de pacientes (64 por ciento) eran menores de 40 años. La frecuencia de pruebas positivas y la especificidad de la prueba con ISB SL es de 60 por ciento y 92 por ciento, respectivamente. Conclusiones: La PI estimulada con ISB presenta buena sensibilidad, especificidad y valor predictivo positivo, es comparable a la estimulación con isoproterenol, que es la técnica más usada, y es rápida y simple. Recomendamos su uso rutinario para el diagnóstico de síncope recurrente de origen no detrminado.
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Hipotensión Controlada , Hipotensión Ortostática , Dinitrato de Isosorbide , SíncopeRESUMEN
Se evalúan diferentesaspectos relacionados con la formación de especialistas médicos. Existe coincidencia en la selección (59] y en la oferta (60], de las llamadas especialidades básicas, para los postulantes, para los postulantes a residencia médica. El sistema solo cubre el 35 de la demanda de formación de especialistas. Debe incrementarse el entrenamiento de especialistas en Medicina General, que solo alcanza un 13 del total. En el sistema ha comenzado la formación de especialistas médicos en Salud Pública. Se propone modificar el examen de admisión incorporando preguntas de otras materias médicas y no solamente ciencias clínicas, Los hospitales cumplen regularmente con sus obligaciones de formación universitaria. La Facultad de Medicina está normando los aspectos de formación, pero aún no se da el trascendental paso del reconocimiento pleno de grado académico al especialista, aspectos que retrasa el desarrollo de la docencia-investigación y de los cursos de maestría en epidemiología clínica y doctorado.
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Medicina , Apoyo a la Formación Profesional/tendencias , Educación Médica/métodos , Educación Médica/tendencias , Responsabilidad Legal , Internado y Residencia , Facultades de Medicina/organización & administración , Medicina/métodosRESUMEN
Contenido: Electrofisiologia,bases tecnicas,rutina de interpretecion,electrocardiograma normal,crecimientos auriculares,crecimientos ventriculares,bloqueos de rama,arritmias cardiacas,trastornos de la conducicion,sindrome de preexitacion,isquemia lesion y necrosis,el E.CG. en las valvulopatias,el E.C.G. en la pericarditis,el E.C.G. en la miocardia chagasica cronica,el E.C.G. en el embolismo pulmonar cronica,el E.C.G. en las cardiopatias congenitas,el E.C.G. en las alteraciones electroliticas y por accion de medicamentos,el E.C.G. en los marcapasos
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Electrocardiografía , Electrofisiología , Técnicas y Procedimientos Diagnósticos/clasificación , Relojes Biológicos , Cardiopatías Congénitas , IsquemiaRESUMEN
Se estudia la fraccion de expulsion del ventriculo izquierdo en funcion de la existencia de ritmo sinusal o de fibrilacion suricular, en pacientes con estenosis mitral. La fibrilacion auricular produce disminucion de la fraccion de expulsion de 14 a 24 por ciento del valor base en ritmo sinusal. Se plantea que el patron electrofisiologico de fibrilacion auricular "atonita" y el incremento de dimension de auricula izquierda producen significativa reduccion de la fraccion de expulsion.