Revistas Científicas de la Universidad Peruana Cayetano Heredia
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Fundamental lessons from blunted chemosensory response of carotid body to hypoxia
No full textGlomus cells are synaptically connected with single afferent fiber, and depolarization of the cell should result in increases of [Ca22+]i, neurosecretion and neural discharge. Suppression of K+ current by low PO₂ is supposed to depolarize the glomus cells. Therefore, a blunted chemosensory response can provide a clue to O2 sensing by the cells being insensitive to O₂ But literature showed that K+- O₂ depression by low PO₂ was normal, although the cells did not depolarize. Also, the sensory fiber with blunted hypoxic response showed a normal or supernormal CO₂/H+ response. Accordingly, they should manifest normal or supernormal K+ current depression with raised CO₂/H+ stimuli
The limits of performance at high altitude
No full textThe intensity of maximum exercise involving a large muscle mass that an acclimatized lowlander can sustain at altitude is reduced compared to sea level. In fact, exercise is stopped before the appearance of biochemical signs of peripheral fatigue. One possible hypothesis to explain the reduction of classical biochemical signs of fatigue in the muscle after exhaustive exercise at high altitude could be that central fatigue, induced by a maximally stressed respiratory system, would possibly limit such exercise with large muscle groups before their full potential is elicited. It appears that in controlled laboratory conditions at 5050m the muscular apparatus by itself remains in good condition and in principle capable for work .This seems to be the case only when a small muscle mass is activated. Exhaustion time of dynamic fore arm work at the identical absolute (maximum) load is the same at sea level and altitude, and similar signs of peripheral muscle fatigue develop before exhaustion is reached. By contrast, for similar exhaustion time, the absolute maximum cycling load maintained at 5050m is -20% lower than at sea level. Furthermore, while exhaustion during leg exercise at sea level is accompanied both by biochemical and electromyographical signs of peripheral fatigue, this is not the case at high altitude. Thus, at altitude, central rather than peripheral fatigue limits exhaustive exercise carried out with large muscle groups. Such mechanism could, at least partially, explain the decreased accumulation of lactic acid in blood in acclimatized subjects during exhaustive exercise at high altitude ("'lactate paradox') and may represent a possible strategy for preserving vital respiratory functions from failure at altitude. lndeed at high altitude, the diaphragmatic contribution to ventilation during exercise at the same relative load decreases with time. This seems to be due to diaphragmatic fatigue, which hypothetically may contribute to exercise limitation at high altitude, although other mechanisms, like decreasing oxygen availability at the level of the central nervous system, may also play a role in limiting the duration of exhaustive exercise in conditions of chronic hypobaric hypoxia
Cardiopulmonary transition in the neonate and infant at high altitude
No full textObjective: Altitude-related alterations in arterial oxygen saturation (Sa O2), ventilation, and the pulmonary circulation occur during cardiopulmonary transition in the neonate and infant at high altitude. Design: Evidence gathered from original research and the published literature allows comparison of various population groups resident at high altitude in North and South American and Asia.
Material and Methods: Data from pulse oximetry, respiratory plethymography, echocardiography, cardiac catheterization and histologic examination of neonates and infants illustrate alterations in function, instances of successful adaptation, and examples of morbidity and mortality related to birth or residence at high altitude.
Results: Sa O2 falls with increasing altitude; however, this effect is not linearly related to altitude or barometric pressure. Sa O2 varies markedly with behavioral state. In contrast to patterns observed at sea level, Sa O2 decreases after 1 week of lifee in certain populations at high altitude. Periodic breathing in infancy increases in prevalence and duration at high altitude as compared to sea level. Periodic breathing occurs most commonly in active and quiet sleep and is associated with a cyclic pattern of oxygen saturation. Pulmonary artery pressure falls slowly after birth at extreme high altitude. At moderate high altitude, pulmonary artery pressures may normalize, but the pulmonary vascular bed remains susceptible to development of symptomatic pulmonary hypertension during a prolonged transition period. The syndrome of subacute infantile mountain sickness an persistence of right-to-left shunts at the foramen ovale and ductus arteriousus reflect elevated pulmonary artery pressure and pulmonary vascular resistance in infancy.
Conclusion: The newborn infant at high altitude experiences a slower transition from fetal to mature patterns of cardiopulmonary function. Defferential effects occur with increasing altitude and differences in response are observed among various population groups at similar altitudes. 
Candidemia y susceptibilidad a antifúngicos en hospitales peruanos
Get PDFWorldwide, Candida bloodstream infections have presented an increase in non-albicans Candida species and resistance to antifungal agents. Objective: To describe the microbiological characteristics of consecutive Candida blood culture isolates. Methods: This study analyzed 73 consecutive Candida blood isolates recovered between July 2017 and July 2019 from routine patient care at 15 Peruvian hospitals, assessing susceptibility to four antifungal agents. Results: The species most frequently detected were Candida parapsilosis 39 (53.4%), Candida albicans 23 (31.5%), and Candida tropicalis 5 (6.8%). Conclusions: All isolates were susceptible to amphotericin B, fluconazole, voriconazole, and anidulafungin. There is a predominance of non-albicans Candida cases in Peru and a high susceptibility to current antifungal drugs.A nivel mundial, las infecciones del torrente sanguíneo por Candida han mostrado un incremento de especies de Candida no albicans y de resistencia a los agentes antifúngicos. Objetivo: Describir las características microbiológicas de aislamientos consecutivos de hemocultivos de Candida. Material y métodos: Se analizaron 73 aislamientos consecutivos de Candida en hemocultivos recuperados entre julio de 2017 y julio de 2019 durante la atención clínica rutinaria en 15 hospitales peruanos, evaluando la susceptibilidad a cuatro agentes antifúngicos. Resultados: Las especies más frecuentemente detectadas fueron Candida parapsilosis 39 (53,4%), Candida albicans 23 (31,5%) y Candida tropicalis 5 (6,8%). Conclusiones: Todos los aislamientos fueron susceptibles a anfotericina B, fluconazol, voriconazol y anidulafungina. Se observa un predominio de casos por Candida no albicans en el Perú y una alta susceptibilidad a los antifúngicos actualmente disponibles
Réplica a la carta al editor: Ferritina y hemoglobina neonatal: ¿Es necesaria la toma de muestras directa? Un debate
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Enfermedades dermatológicas por exposición al petróleo: una revisión narrativa de la literatura
Get PDFFew studies have explored the dermatological effects of exposure to petroleum. This narrative review aimed to identify the most common skin diseases related to this exposure. A literature search from 2019 to 2024 was performed in PubMed, Scopus, SciELO, and LILACS in both English and Spanish. Fifty-two publications were included. Petroleum mainly consists of hydrocarbons; polycyclic aromatic hydrocarbons induce skin effects through a cycle of oxidative stress, inflammation, and skin barrier dysfunction. Frequently reported conditions included acne, cancer, dermatitis, burns, pigment changes, and unspecified disorders. Nail and hair issues were also noted. Exposure to petroleum induces distinct dermatological pathologies and worsens existing conditions. More epidemiological and experimental studies are needed to fully understand the underlying mechanisms.Pocos estudios han profundizado en los efectos dermatológicos de la exposición al petróleo. El objetivo de esta revisión narrativa de la literatura fue describir las dermopatías más frecuentes en este contexto. Se realizó una búsqueda bibliográfica en las bases de datos PubMed, Scopus, SciELO y LILACS, desde 2019 a 2024, tanto en inglés como en español. Se seleccionaron 52 publicaciones para su síntesis y revisión. El petróleo está compuesto principalmente por hidrocarburos. Los hidrocarburos aromáticos policíclicos generan una serie de efectos en la piel, a través de procesos biológicos que comprenden estrés oxidativo, inflamación y defectos de la barrera cutánea. El acné, cáncer, dermatitis, quemaduras, alteraciones de la pigmentación y otros trastornos no especificados fueron las dermopatías que más se reportaron. Las patologías ungueales y del cabello también fueron identificadas. Finalmente, la exposición al petróleo da origen a condiciones patológicas específicas de la piel y exacerba otras preexistentes. Se requieren de más estudios epidemiológicos y experimentales para comprender completamente los mecanismos fisiopatológicos subyacentes.
Cirurgia oral em pacientes em uso de anticoagulantes orais clássicos e diretos: uma revisão da literatura
Get PDFFor decades, vitamin K antagonists such as warfarin have been the standard anticoagulant treatment, despite the clinical management challenges they present. In contrast, direct oral anticoagulants (DOACs) offer fewer complications and therapeutic advantages. These are classified into thrombin inhibitors (dabigatran) and factor Xa inhibitors (rivaroxaban, apixaban, edoxaban). Approximately 10% of anticoagulated patients will require some form of surgery, including oral surgery. In this context, the objective of this review was to update oral surgical management in anticoagulated patients and to familiarize dentists with protocols for warfarin and DOAC users. Discontinuing anticoagulant therapy carries significant and even fatal risks, which in many cases outweigh the benefits of reducing bleeding during oral surgery. It is concluded that anticoagulant therapy should only be suspended for procedures with a high risk of bleeding, and it is essential to evaluate the bleeding risk of the procedure beforehand and apply hemostatic measures when necessary.Durante décadas, los antagonistas de la vitamina K, como la warfarina, han constituido el tratamiento anticoagulante de referencia, a pesar de las dificultades asociadas a su manejo clínico. En contraste, los anticoagulantes orales de acción directa (ACOD) ofrecen menos complicaciones y ventajas terapéuticas. Estos se dividen en inhibidores de la trombina (dabigatrán) e inhibidores del factor Xa (rivaroxabán, apixabán, edoxabán). Aproximadamente, el 10 % de los anticoagulados requerirán alguna cirugía, incluida la bucal. En este contexto, el objetivo de esta revisión fue actualizar el conocimiento sobre el manejo quirúrgico bucodental en pacientes anticoagulados y familiarizar a los odontólogos con los protocolos en usuarios de warfarina y ACOD. Suspender la terapia anticoagulante implica riesgos significativos e incluso fatales, superando en muchos casos los beneficios de reducir el sangrado en una cirugía bucal. Se concluye que la suspensión de los anticoagulantes solo debe considerarse en procedimientos con alto riesgo de sangrado, siendo indispensable evaluar previamente el riesgo hemorrágico del procedimiento y aplicar medidas hemostáticas en caso sea necesario.Durante décadas, os antagonistas da vitamina K, como a varfarina, foram a terapia anticoagulante padrão ouro, apesar das dificuldades associadas ao seu manejo clínico. Em contraste, os anticoagulantes orais de ação direta (DOAC) oferecem menos complicações e vantagens terapêuticas. Eles são divididos em inibidores de trombina (dabigatran) e inibidores do fator Xa (rivaroxaban, apixaban, edoxaban). Aproximadamente 10% das pessoas anticoaguladas precisarão de cirurgia, inclusive cirurgia oral. Nesse contexto, o objetivo desta revisão foi atualizar o manejo cirúrgico oral em pacientes anticoagulados e familiarizar os dentistas com os protocolos em usuários de varfarina e DOAC. A interrupção da terapia anticoagulante envolve riscos significativos e até mesmo fatais, superando em muitos casos os benefícios da redução do sangramento em cirurgia bucal. Conclui-se que a descontinuação de anticoagulantes só deve ser considerada em procedimentos com alto risco de sangramento, com avaliação prévia do risco hemorrágico do procedimento e aplicação de medidas hemostáticas, se necessário
Adquisición de la adaptación fisiologica a la altura
No full textEl stress de la baja presión del oxígeno presente en la altura requiere una respuesta conjunta del sistema cardiorespiratorio. Por tanto las investigaciones de altura han estado dirigidas a determinar las características respiratorias, cardíacas y hematológicas de los visitantes y de los nativos de la altura. Durante los últimos años las investigaciones conducidas tanto en los Andes Americanos como en las Himalayas permiten determinar el proceso de adaptación fisiológica a la altura.
En esta presentación se hace una revisión de los estudios realizados en los Andes Americanos y los Himalayas con el propósito de demostrar que una adaptación completa desde el punto de vista funcional es adquirida durante el proceso de desarrollo y crecimiento. Se presenta, además, las diferencias que existen entre una adaptación adquirida durante el estado adulto y aquel producido durante el periodo de crecimiento, concluyendo con un esquema general acerca de los mecanismos que operan para una adaptación fisiológica a la altura