Bioprospection of Native Antagonistic Rhizobacteria From the Peruvian Coastal Ecosystems Associated with Phaseolus vulgaris.

Phaseolus vulgaris is originally from the American continent. It is renowned as one of the preferred legume choice in the Peruvian market, due to its high content of nutrients. The Peruvian coast valleys are key-production areas for local varieties of the common bean crops. Soil-borne plant pathogens, however, favored by soil and environmental conditions, may reduce crop production. The aim of this study was to conduct a bio prospection of the antagonistic native bacteria of the north, south and central part of the coastal areas related to the common bean. A collection of 26 strains isolated from the rhizosphere of common bean plants showed high potential to control the growth of Sclerotinia, Fusarium and Rhizoctonia due to the production of both volatile and non-volatile organic compounds. Most of the strains were able to suppress fungal growth due to the presence of non-volatile organic compounds, such as hydrolytic enzymes, siderophores and antifungal lipopeptide production. Bacillus IcBac2.1 strain showed a remarkable ability to halt the majority of phytopathogens producing antifungal lipopeptides. The crude lipopeptides were soluble in polar solvents and remained stable at high temperatures and low pH. Strains were also able to inhibit fungal growth through volatile organic compounds. Alcaligenes TvPs2.4 and Pseudomonas TvPs1.6 showed the highest inhibition strength against the tested phytopathogens. Each strain produced 21 volatile organic compounds detected by SPME/GC-MS analysis. The compounds with the highest concentration were dimethyl disulfide and D-limonene. The 16S rRNA gene sequence confirmed that the strains were closely related to Bacillus, Paenibacillus, Achromobacter, Pseudomonas, Serratia and Alcaligenes.

Tratamiento exitoso de lipodermatoesclerosis aguda con doxiciclina: reporte de diez casos / Successful treatment of acute lipodermatosclerosis with doxycycline: report of ten cases

Resumen La doxiciclina, una tetraciclina semisintética de segunda generación, ampliamente usada para el tratamiento de patologías dermatológicas por sus propiedades antimicrobianas, ha demostrado en varios estudios experimentales sus acciones como un potente fármaco antiinflamatorio, aprobado por estas características por la FDA como una terapia complementaria en la periodontitis del adulto, así como en el tratamiento de la forma papulopustulosa de la rosácea. Se describen además en la literatura otras indicaciones para procesos inflamatorios, tales como, calcinosis cutis, vasculitis livedoide, patologías ampollares, entre otras. Se presenta una serie de 10 pacientes con lipodermatoesclerosis que presentaron una respuesta eficaz a su patología al recibir tratamiento con doxiciclina durante 3 meses, destacando de esta forma su eficacia terapéutica, accesibilidad y baja asociación a efectos adversos.

Abstract Doxycycline, a second generation semi-synthetic tetracycline, widely used for the treatment of dermatological diseases for its antimicrobial effects, has shown in many clinical studies its actions as a powerful anti-inflammatory drug. Approved by the FDA as a complementary therapy in adult periodontitis, and of the papulopustular form of rosacea. In addition, other indications for inflammatory processes are described in the literature, such as calcinosis cutis, livedoid vasculitis, blistering pathologies, among others. We present a series of 10 patients with lipodermatosclerosis who presented an effective response to their pathology when receiving treatment with doxycycline for 3 months. Its therapeutic efficacy, accessibility and low association with adverse effects are highlighted.

Laparoscopic Liver Resection: A South American Experience with 2887 Cases.

BACKGROUND: Laparoscopic liver resections (LLR) have been increasingly performed in recent years. Most of the available evidence, however, comes from specialized centers in Asia, Europe and USA. Data from South America are limited and based on single-center experiences. To date, no multicenter studies evaluated the results of LLR in South America. The aim of this study was to evaluate the experience and results with LLR in South American centers. METHODS: From February to November 2019, a survey about LLR was conducted in 61 hepatobiliary centers in South America, composed by 20 questions concerning demographic characteristics, surgical data, and perioperative results. RESULTS: Fifty-one (83.6%) centers from seven different countries answered the survey. A total of 2887 LLR were performed, as follows: Argentina (928), Brazil (1326), Chile (322), Colombia (210), Paraguay (9), Peru (75), and Uruguay (8). The first program began in 1997; however, the majority (60.7%) started after 2010. The percentage of LLR over open resections was 28.4% (4.4-84%). Of the total, 76.5% were minor hepatectomies and 23.5% major, including 266 right hepatectomies and 343 left hepatectomies. The conversion rate was 9.7%, overall morbidity 13%, and mortality 0.7%. CONCLUSIONS: This is the largest study assessing the dissemination and results of LLR in South America. It showed an increasing number of centers performing LLR with the promising perioperative results, aligned with other worldwide excellence centers.

Antipredator behavior of the new mass-reared unisexual strain of the Mexican Fruit Fly.

Tephritid pests controlled through the sterile insect technique (SIT) are mass-reared and subsequently released in affected areas. Several quality parameters are currently used to test adults, but none take into account interactions with a predator. When sterile males are released in the field, they will need to avoid predators until they reach sexual maturity and survive long enough to mate with wild females. Spiders are one of the most common predators that flies may encounter in release sites. In this study, we evaluated the antipredator behavior of a mass-reared sterile unisexual strain ('Tapachula-7') of the Mexican fruit fly Anastrepha ludens (Diptera: Tephritidae) against their spider predators. We sampled spiders in citrus trees to determine which families could be more common. We established the baseline activity rates of sterile Tapachula-7 (Tap-7) flies in comparison with wild flies. We also tested the behavior of the fertile and sterile bisexual strain and wild flies against hunting spiders (Family Salticidae) and orb building spiders (Family Tetragnathidae). We recorded 18 spider families, with Salticidae being the most dominant. Tap-7 flies diminished their activity in comparison with wild males at 1800 h but showed similar activity levels earlier in the day. When exposed to orb-web spiders (Leucauge venusta), Tap-7, fertile and sterile males from the bisexual strain had similar rates of survival, but Tap-7 males showed lower survival than wild males. Against hunting spiders (Phidippus audax), wild males had higher probability of defensive wing displays, but there was no difference in spider attack rates. In general, sterile Tap -7 males performed as well as males from the bisexual strain, although they had lower survival than wild males. This could be due to either mass-rearing and/or irradiation effects. We recommend the use of the defensive wing display behavior as a quality parameter and propose a rapid and effective method to evaluate fly activity. The efficiency of SIT will be improved if released sterile males have the same antipredator repertoire as their wild counterparts.

Estrés postraumático en escolares a 8 meses del 27F / Post-traumatic stress disorder in children eight months after february 27, 2010

Introduction: there are several epidemiological studies regarding the incidence of post-traumatic stress disorder (PTSD) in children exposed to natural disasters. Objective: to describe the prevalence of PTSD in a school-age population in a coastal town from the Maule Region, 8 months after the earthquake/tsunami in february 2010, and to compare differences among PTSD groups of symptom (re-experiencing, avoidance and activation) according to demographic variables such as age, grade, gender and family type. Methodology: the Child PTSD Symptom Scale (CPSS), validated in Chile in 2009, was used in 89 children between 3rd and 6th grade, corresponding to 94.7 percent of the children enrolled in the local school in such classes. Data are analyzed by gender, age, grade and type of family. 89 surveys were applied, 59.6 percent were male and 40.4 percent female aged 8-13. Results: 40.4 percent of children had symptoms consistent with PTSD, with higher incidence in women and younger children; the most significant association among women was age. Both groups (women and young children) presented the highest scores on all group of symptoms. There were no differences by type of family. Conclusions: the incidence of PTSD measured by CPSS scale in the study population was 40.4 percent, considered to be among the highest percentages reported in the international literature.

Introducción: existen diversos datos epidemiológicos respecto a la incidencia de Trastorno por Estrés Pos-traumático (TEPT) en niños expuestos a desastres naturales. Objetivo: describir la prevalencia de TEPT en una población infantil escolarizada de una localidad costera de la Región del Maule después de 8 meses de ocurrido el terremoto/maremoto de febrero/2010, y comparar las diferencias entre grupos de síntomas del TEPT (reexperimentación, evitación y activación) según variables demográficas, como edad, curso, sexo y tipo de familia. Metodología: se aplicó la escala Child PTSD Symptom Scale (CPSS) validada en Chile el año 2009, a 89 niños de 3° a 6° básico lo que corresponde al 94,7 por ciento de los niños matriculados en la escuela de la localidad en dichos cursos. Se analizan los datos según sexo, edad, curso y tipo de familia. Se aplicaron 89 encuestas, 59,6 por ciento eran varones y 40,4 por ciento mujeres de 8 a 13 años de edad. Resultados: el 40,4 por ciento del total de niños tuvo una evaluación compatible con TEPT, con mayor incidencia en mujeres y niños de menor edad, siendo la edad un factor de asociación significativa en las mujeres. Ambos grupos (mujeres y niños más pequeños) presentaron mayores puntajes en todos los grupos sintomáticos. No se encontraron diferencias según el tipo de familia. Conclusiones: la incidencia de TEPT medida a través de la escala CPSS en la población estudiada fue de 40.4 por ciento, encontrándose entre las más altas reportadas en la bibliografía internacional.

Intervención de salud mental en niños expuestos a desastre natural / Mental health intervention in children exposed to natural disasters

Introduction: this study is part of the mental health intervention, conducted by a child psychiatry team for children exposed to the february 2010 earthquake/tsunami in a community of the VII Region that was strongly affected by the natural disaster. Objective: to describe the intervention and evaluate the effectiveness of the strategies implemented for both children and teachers. Methodology: interventions are described and classified in three categories. (1) Case report and child care consulting, referred by their teacher. (2) Psychoeducational workshops for teachers of the intervened school. (3) Self-Care day aimed at professionals of the same school. The evaluation is done through an anonymous survey designed to measure the effectiveness of the intervention. Results: 33 children were evaluated and treated, the most common diagnoses were adaptive disorders (8/33) and ADHD (11/33), and only 3 patients met the criteria for post-traumatic stress disorder (PTSD). Intervention implementation included psychoeducation for parents (100 percent), coordination with schools and local health network (100 percent), counseling (70 percent) and drug prescription (45 percent). Only 45 percent of the cases evaluated had symptoms triggered or exacerbated by the earthquake/tsunami. Regarding teacher evaluation (N: 11), 100 percent described the intervention as "very good". 90 percent considered it appropriate to the needs at the moment and as a contribution to their educational work. Conclusions: after events of this nature, many interventions take place to support the affected population. It is important to have more scientific information about the effectiveness of such interventions to prevent the development of post-traumatic psychopathology.

Introducción: este trabajo forma parte de la intervención de salud mental, realizada por un equipo de psiquiatría infantil para niños expuestos al terremoto/maremoto de febrero de 2010, en una comunidad de la VII Región fuertemente afectada por el desastre natural. Objetivos: describir la intervención realizada y evaluar la efectividad de las estrategias implementadas tanto a niños como a profesores. Metodología: se describe las intervenciones realizadas, clasificadas en 3 categorías: 1) Consultoria de casos clínicos y atención de niños derivados por sus profesores. 2) Talleres psicoeducativos a profesores de la escuela intervenida. 3) Jornada de autocuidado, dirigida a los profesionales de la misma escuela. La evaluación se realiza a través de encuesta anónima a los profesores diseñada para cuantificar la efectividad de la intervención. Resultados: se evaluaron y trataron 33 niños, los diagnósticos más frecuentes fueron Trastornos adaptativos (8/33) y Déficit atencional (11/33); sólo 3 casos cumplían criterios de Trastorno por Estrés Postraumático(TEPT). Las intervenciones utilizadas incluyeron psicoeducación a padres (100 por ciento), coordinación con colegios y red de salud municipal (100 por ciento), apoyo psicológico (70 por ciento) y farmacológico (45 por ciento). Sólo en el 45 por ciento de los casos evaluados la sintomatología se había desencadenado o agravado con el terremoto/maremoto. En relación a la evaluación de profesores (n: 11), 100 por ciento consideró la intervención como "muy buena". Un 90 por ciento la consideró adecuada a las necesidades y constituyó un aporte a su quehacer educativo. Conclusiones: tras eventos como éste, se realizan variadas intervenciones de apoyo a la población afectada. Es importante contar con mayor información científica acerca de la efectividad de dichas intervenciones para prevenir el desarrollo de psicopatología postraumática.

A new generation of X ray irradiators for insect sterilization.

Recent fears of terrorism have provoked an increase in delays and denials of transboundary shipments of radioisotopes. This represents a serious constraint to sterile insect technique (SIT) programs around the world as they rely on the use of ionizing radiation from radioisotopes for insect sterilization. To validate a novel X ray irradiator, a series of studies on Ceratitis capitata (Wiedemann) and Anastrepha fraterculus (Wiedemann) (Diptera: Tephritidae) were carried out, comparing the relative biological effectiveness (RBE) between X rays and traditional gamma radiation from 60Co. Male C. capitata pupae and pupae of both sexes of A. fraterculus, both 24-48 h before adult emergence, were irradiated with doses ranging from 15 to 120 Gy and 10-70 Gy, respectively. Estimated mean doses of 91.2 Gy of X and 124.9 Gy of gamma radiation induced 99% sterility in C. capitata males. Irradiated A. fraterculus were 99% sterile at approximately 40-60 Gy for both radiation treatments. Standard quality control parameters and mating indices were not significantly affected by the two types of radiation. The RBE did not differ significantly between the tested X and gamma radiation, and X rays are as biologically effective for SIT purposes as gamma rays are. This work confirms the suitability of this new generation of X ray irradiators for pest control programs that integrate the SIT.

Tricobezoar gástrico e intestinal en adolescente femenina de 15 años: a propósito de un caso clínico IVSS "Dr. Tulio Carnevali Salvatierra" Mérida-Venezuela / Gastric and intestinal trichobezoar female teenager about 15 years: a purpose of case clinical in IVSS Dr. Tulio Carnevali Salvatierra

Los tricobezoar son recolecciones de material ingerido (pelos, fibras) que se acumulasn en estómago e intestino. Se originan de la tricotilomanía más tricofagia, cuando el tricobezoar se acumula en duodeno recibe el nombre de Sídrome de Rapunzel, más frecuente en el sexo femenino. Adolescente de 15 años, quien presentó dolor abdominal de aparición insidiosa acompañada de naúseas y vómitos incontables que se irradian a hipocondrio y fosa iliaca izquierda, su evolución fue torpida presentando signos de irritación peritoneal. Se realiza laparatomía exploradora hallándose tumor de contenido de pelo a nivel del Ángulo de Treitz, y cámara gástrica. Siendo egresada y referida al servicio de psiquiatría infanto-juvenil.

Reconstrucción facial con colgajos locales / Facial reconstruction with local flaps

Este trabajo tiene como objetivo conocer la evolución clínica de pacientes sometidos a reconstrucciones faciales con empleo de colgajos locales. Estudio prospectivo, descriptivo y observacional, diseño no experimental. Se presentan cuatro (4) casos clínicos, pacientes masculinos, a dos (2), se les diagnóstica mediante biopsia Carcinoma Basocelular, a uno (1) Carcinoma Espinocelular y al otro Carcinoma Epidermoide, se les practica excéresis de las lesiones que presentan y posteriormente en el mismo acto quirúrgico, se realiza colocación de colgajos, utilizando para ésto piel y en un caso músculo, de diferentes regiones de la cara. Evolución funcional y estética satisfactoria.

Acranea: a propósito de un caso / Acranea: a purpose of a case

La acranea es la anomalía fetal caracterizada por la ausencia de la bóveda craneana, acompañado de un completo tejido cerebral. Su causa es debida a una falla en la migración del mesenquima ectodernal o a una discrupción de las bandas amnióticas. La incidencia no es conocida, muy pocos casos han sido reportados en la literatura mundial. El diagnóstico prenatal se identifica por la ausencia de la bóveda craneana a través de la ultrasonografía. El pronóstico es fatal. Nosotros reportamos nuestra experiencia en un feto diagnosticado por ultrasonografía con acranea a las 12 semanas de edad gestacional.

Quemaduras: rutina de atención quirúrgica / Burns: routine surgical care

La destrucción de los tegumentos, incluso en los tejidos subyacentes, bajo el efecto de un agente térmico, eléctrico, químico o radioactivo; está en relación con la extensión y profundidad de la lesión nos lleva como definición a una patología extremadamente grave y compleja. Presentamos de manera sucinta la incidencia de quemaduras, rutina de atención al quemado y el resultado de aplicación de esta rutina en el Instituto Autónomo Hospital Universitario de Los Andes, Hospital tipo IV, situado en Mérida Edo. Mérida desde el 2000 hasta el 2006 y que por su área de atención, nuestro Servicio está comprometido en el manejo quirúrgico de estas lesiones, sin embargo aun teniendo la necesidad de poseer un área especial para la atención de los pacientes quemados, no contamos con dicha infraestructura.

Expandiendo la atención integrada de las enfermedades prevalentes de la infancia a nivel nacional: logros y retos en el Perú / Scaling up integrated management of childhood illness to national level: achievements and challenges in Peru

Este artículo presenta el primer reporte publicado de un esfuerzo nacional de implementación de la atención integrada a las enfermedades prevalentes de la infancia (Aiepi) en gran escala. Es el primer reporte publicado de un esfuerzo nacional de implementación de la atención integrada a las enfermedades prevalentes de la infancia (Aiepi) en gran escala. Aiepi fue introducido en el Perú a finales de 1996; la fase de implementación inicial empezó en 1997 y la de expansión en 1998. Comunicamos aquí los resultados de una evaluación retrospectiva diseñada para describir y analizar el proceso de captación de Aiepi a nivel nacional en el Perú, evaluación conducida como parte de los cinco estudios de la evaluación multipaís de la efectividad, costo e impacto de Aiepi (EMP), coordinada por la Organización Mundial de la Salud. Supervisores capacitados visitaron las 34 direcciones de salud (Disas) del Perú, entrevistaron al personal de las Disas y revisaron los registros existentes. Los resultados muestran que Aiepi no fue institucionalizado en el Perú; fue implementado paralelamente a los programas existentes de control de infecciones respiratorias agudas y diarrea, compartiendo con ellos presupuesto y personal. El número de personal de salud capacitado en Aiepi aumentó hasta 1999 y luego disminuyó en el 2000 y el 2001, con una cobertura para médicos y enfermeras estimada en 10,3 por ciento . La implementación del componente comunitario de Aiepi empezó el año 2000 con la capacitación de agentes comunitarios de salud, pero no se efectivizaron las sinergias esperadas entre las intervenciones en los establecimientos de salud y las intervenciones comunitarias, pues las Disas en los que la capacitación clínica fue más intensa no fueron las mismas en las que la capacitación en Aiepi comunitario fueron las más fuertes. Se presenta las limitaciones encontradas para la expansión nacional de Aepi y las implicancias políticas de los hallazgos. Hubo pocos documentos de monitoreo...

Expansión de la atención integrada a las enfermedades prevalentes de la infancia en el Perú / Implementation of the integrated management of chilhood illnesses strategy in Peru and its association with health indicators: an ecological analysis

Objetivos: 1) Documentar las tendencias en la implementación de la atención integrada a las enfermedades prevalentes de la infancia (Aiepi) en los 24 departamentos del país, de 1996 al 2000. 2) Documentar las tendencias en los indicadores de cobertura de servicios de salud y en los de impacto (mortalidad y estado nutricional) para el mismo período. 3) Correlacionar los cambios en estos dos grupos de indicadores. Y, 4) intentar descartar factores contextuales que puedan afectar las tendencias y las correlaciones observadas. Materiales y Métodos: Se realizó un análisis ecológico en el que las unidades de estudio fueron los 24 departamentos. Resultados: Para el 2000, 10,2 por ciento de trabajadores clínicos (médicos y enfermeras) fueron capacitados en Aiepi, pero solo algunos departamentos mostraron tasas considerablemente mayores. No hubo asociaciones significativas entre la cobertura de capacitación clínica en Aiepi y los indicadores de utilización de consultas externas, cobertura de vacunas, mortalidad o desnutrición. La falta de asociación persistió luego de haber realizado el ajuste de varios factores contextuales incluyendo indicadores socioeconómicos y ambientales y la presencia de otros proyectos de salud del niño. Los agentes comunitarios de salud también fueron capacitados en Aiepi y la cobertura de capacitación no estuvo asociada con ninguno de los indicadores de proceso o de impacto, excepto una correlación positiva y significativa con el promedio de talla para edad. De acuerdo al modelo de impacto de la Evaluación Multi-País del Impacto, Costo y Efectividad de Aiepi (EMP), la implementación de Aiepi debe ser lo suficientemente fuerte para llevar a un impacto en la salud y la nutrición. Conclusiones: El soporte de los sistemas de salud para la implementación de Aiepi en el Perú estuvo lejos de ser adecuada, y esto, así como coberturas de capacitación relativamente bajas, pueden explicar porqué no se documentó el impacto esperado. Sin embargo, inclus...

Autonomic nervous system dysfunction in children with severe tetanus: dissociation of cardiac and vascular sympathetic control.

The medical records of ten pediatric patients with a clinical diagnosis of tetanus were reviewed retrospectively. The heart rate and blood pressure of all tetanus patients were measured noninvasively every hour during the first two weeks of hospitalization. Six of ten tetanus patients presented clinical evidence of sympathetic hyperactivity (group A) and were compared with a control group consisting of four children who required mechanical ventilation for diseases other than tetanus (group B). Heart rate and blood pressure simultaneously and progressively increased to a maximum by day 7. The increase over baseline was 43.70 +/- 11.77 bpm (mean +/- SD) for heart rate (P<0.01) and 38.60 +/- 26.40 mmHg for blood pressure (P<0.01). These values were higher and significantly different from those of the control group (group B) at day 6, which had an average heart rate increase over baseline of 19.35 +/- 12.26 bpm (P<0.05) and blood pressure of 10.24 +/- 13.30 mmHg (P<0.05). By the end of the second week of hospitalization, in group A the increase of systolic blood pressure over baseline had diminished to 9.60 +/- 15.37 mmHg (P<0.05), but the heart rate continued to be elevated (27.80 +/- 33.92 bpm, P = NS), when compared to day 7 maximal values. The dissociation of these two cardiovascular variables at the end of the second week of hospitalization suggests the presence of asymmetric cardiac and vascular sympathetic control. One possible explanation for these observations is a selective and delayed action of tetanus toxin on the inhibitory neurons which control sympathetic outflow to the heart.

Autonomic nervous system dysfunction in children with severe tetanus: dissociation of cardiac and vascular sympathetic control

The medical records of ten pediatric patients with a clinical diagnosis of tetanus were reviewed retrospectively. The heart rate and blood pressure of all tetanus patients were measured noninvasively every hour during the first two weeks of hospitalization. Six of ten tetanus patients presented clinical evidence of sympathetic hyperactivity (group A) and were compared with a control group consisting of four children who required mechanical ventilation for diseases other than tetanus (group B). Heart rate and blood pressure simultaneously and progressively increased to a maximum by day 7. The increase over baseline was 43.70 + or - 11.77 bpm (mean + or - SD) for heart rate (P<0.01) and 38.60 + or - 26.40 mmHg for blood pressure (P<0.01). These values were higher and significantly different from those of the control group (group B) at day 6, which had an average heart rate increase over baseline of 19.35 + or - bpm (P<0.05) and blood pressure of 10.24 + or - mmHg (P<0.05). By the end of the second week of hospitalization, in group A the increase of systolic blood pressure over baseline had diminished to 9.60 + or - mmHg (P<0.05), but the heart rate continued to be elevated (27.80 + or - 0 bpm, P = NS), when compared to day 7 maximal values. The dissociation of these two cardiovascular variables at the end of the second week of hospitalization suggests the presence of asymmetric cardiac and vascular sympathetic control. One possible explanation for these observations is a selective and delayed action of tetanus toxin on the inhibitory neurons which control sympathetic outflow to the heart

Heart rate responses to a muscarinic agonist in rats with experimentally induced acute and subacute chagasic myocarditis.

We administered arecoline to rats, with experimentally induced chagasic myocarditis, in order to study the sinus node sensitivity to a muscarinic agonist. Sixteen month old rats were inoculated with 200,000 T. cruzi parasites ("Y" strain). Between days 18 and 21 (acute stage), 8 infected rats and 8 age-matched controls received intravenous arecoline as a bolus injection at the following doses: 5. 0, 10.0, 20.0, 40.0, and 80.0 microg/kg. Heart rate was recorded before, during and after each dose of arecoline. The remaining 8 infected animals and 8 controls were subjected to the same experimental procedure during the subacute stage, i.e., days 60 to 70 after inoculation. The baseline heart rate, of the animals studied during the acute stage (349 +/- 68 bpm, mean +/- SD), was higher than that of the controls (250 +/- 50 bpm, p < 0.005). The heart rate changes were expressed as percentage changes over baseline values. A dose-response curve was constructed for each group of animals. Log scales were used to plot the systematically doubled doses of arecoline and the induced-heart rate changes. The slope of the regression line for the acutely infected animals (r = - 0.99, b =1.78) was not different from that for the control animals (r = - 0.97, b = 1.61). The infected animals studied during the subacute stage (r = - 0.99, b = 1.81) were also not different from the age-matched controls (r = - 0.99, b = 1.26, NS). Consequently, our results show no pharmacological evidence of postjunctional hypersensitivity to the muscarinic agonist arecoline. Therefore, these results indirectly suggest that the postganglionic parasympathetic innervation, of the sinus node of rats with autopsy proved chagasic myocarditis, is not irreversibly damaged by Trypanosoma cruzi.

Cardiac afferents and neurohormonal activation in congestive heart failure.

Cardiac chambers have afferent connections to the brainstem and to the spinal cord. Vagal afferents mediate depressor responses and become activated by volume expansion, increased myocardial contractility and atrial natriuretic factor. Sympathetic afferents, on the contrary, are activated by metabolic mediators, myocardial ischemia and cardiac enlargement. These opposite behaviors may lead to activation or suppression of the sympathetic nervous system and of the renin-angiotensin-aldosterone system. As cardiac diseases progress, the heart dilates, plasma norepinephrine increases, atrial natriuretic factor is released and the renin-angiotensin-aldosterone system is suppressed to maintain water and sodium excretion. This dissociation of the neurohormonal profile of cardiac patients, may be explained by coactivation of sympathetic afferents, by cardiac dilatation, and of vagal afferents by atrial natriuretic factor. In more advanced stages, atrial natriuretic factor suppression of the renin-angiotensin-aldosterone system is overridden by overt sympathetic activation and sodium and water retention ensues. Digitalis, angiotensin-converting enzyme inhibitors and beta-blockers selectively decrease cardiac adrenergic drive. A common mechanism of action, to all three groups of drugs, would be attenuation of sympathetic afferents and partial normalization of vagal afferents. Consequently, heart size and cardiac afferents emerge as the key factors to understand the pathophysiology and treatment of the syndrome of congestive heart failure.

Serial heart rate changes in rats inoculated by conjunctival instillation of Trypanosoma cruzi obtained from bug faeces.

UNLABELLED: The cardiac effects of experimentally induced myocarditis, when the parasite is obtained from mouse blood, are well known. However, the consequences of the infection when the parasites are obtained from bug faeces are less well defined. In the present investigation, we have used the "Y" strain of Trypanosoma cruzi, which was maintained in Rhodnius prolixus by repeated passages in mice. The faeces of 30 infected bugs were collected, the number of parasites counted and 4,000 parasites inoculated by the conjunctival route in 60 rats. Twenty-nine other rats received faeces from noninfected bugs (sham-inoculated controls) and 40 were used as normal controls. The heart rate of the three groups of animals was recorded under general anesthesia with ether. The heart rate, at day 0 pre-inoculation, was similar in the three groups of animals ( CONTROLS: 379 +/- 27 beats/min Mean +/- SD; Sham-inoculated: 366 +/- 31; Infected: 351 +/- 29) (p> 0.05). In the infected animals, the mean heart rate began to increase significantly by day 12 following infection (375 +/- 31), reaching the highest values between days 18 (390 +/- 33) and 21 (403 +/- 33) and returned to baseline by day 30 (359 +/- 28) (p< 0.05). The heart rate changes were statistically different from those observed in the sham-inoculated controls and in the control animals. Therefore, these heart rate changes were provoked by the Trypanosoma cruzi-induced infection. Thus, it appears that irrespective of the source of the parasite and route of inoculation, Trypanosoma cruziacute infection provokes a transient sinus tachycardia.