Follicle development and selection: past, present and future

This paper reviews progress that has been made over the last 50 years and discusses how the development and application of new technologies have been utilized to increase our understanding of the development and selection of the dominant follicle. Our increased knowledge from research carried out worldwide, has demonstrated that the development of the dominant follicle, and importantly the production of a good quality oocyte, are controlled by a set of complex and interactive extra- and intra-ovarian control systems, impacted by underlying genetic and external environmental factors, such as nutrition. In totality this has resulted in improvements in fertility, as demonstrated by the impact of diet on oocyte quality and increased pregnancy rates. However, given the increasing global challenges of food security, coupled with climate change, more in-depth understanding of these complex multifactorial control systems will have even greater significance in overcoming today's livestock production challenges, including some that were present over 50 years ago. In conclusion, the continuing development of new technologies, coupled with new knowledge and understanding of these complex control systems, should ensure that ruminant fertility is maximized, while ensuring good animal welfare within sustainable production systems.

Follicle development and selection: past, present and future

This paper reviews progress that has been made over the last 50 years and discusses how the development and application of new technologies have been utilized to increase our understanding of the development and selection of the dominant follicle. Our increased knowledge from research carried out worldwide, has demonstrated that the development of the dominant follicle, and importantly the production of a good quality oocyte, are controlled by a set of complex and interactive extra- and intra-ovarian control systems, impacted by underlying genetic and external environmental factors, such as nutrition. In totality this has resulted in improvements in fertility, as demonstrated by the impact of diet on oocyte quality and increased pregnancy rates. However, given the increasing global challenges of food security, coupled with climate change, more in-depth understanding of these complex multifactorial control systems will have even greater significance in overcoming today's livestock production challenges, including some that were present over 50 years ago. In conclusion, the continuing development of new technologies, coupled with new knowledge and understanding of these complex control systems, should ensure that ruminant fertility is maximized, while ensuring good animal welfare within sustainable production systems.(AU)

Leucemia linfoblástica aguda en pacientes portadores de síndrome de Down / Acute lymphoblastic leukemia in children with Down's syndrome

Background: Children with Down's Syndrome (DS) present a higher incidence of Acute Lymphoblastic Leukemia (ALL) with more complications and shorter survival than healthy children. Objective: To describe clinical characteristics, laboratory and treatment results in patients with DS and ALL. Patients and Method: Retrospective analysis of 42 DS and ALL patients treated in three consecutive trials (1992,1996,2002) from the Pediatric National Cancer Program (PINDA). Clinical data, immunophenotype, cytogenetics and treatment results were analyzed. Results: There was no difference by age or gender, no patient presented LLA-T, t (9;22) o t (4;11). Of the 42 patients, 38 patients went into remission, 10 relapsed (26,3 percent, 11 died because of infection, none died from other toxicity. Survival at 5 years was 35 +/- 9 percent (median of follow-up was 50 mo), similar for all protocols (p = 0,61). Conclusion: The group of patients with ALL and DS evaluated was not associated with classic treatment resistance factors. The relapse rate was not increased, if compared with non DS ALL patients; in this group the infections were the determinant factor for a lower survival. These patients can be treated with the current trials but they require a detailed infection care.

Los niños con Síndrome de Down (SD) tienen mayor incidencia de leucemia linfoblástica aguda (LLA) con más complicaciones y menor sobrevida que los niños sin SD. Objetivo: Describir características clínicas, de laboratorio y resultados de tratamiento en niños con SD y LLA. Pacientes y Método: Análisis retrospectivo de 42 pacientes con LLA y SD tratados en 3 protocolos consecutivos (1992, 1996 y 2002) del Programa Nacional de Cáncer Infantil (PINDA). Se analizaron datos clínicos, de laboratorio, inmunofenotipo, citogenética y resultados de tratamiento. Resultados: La distribución por género o grupo etario no mostró diferencias, ningún paciente presentó LLA-T, t (9;22) o t (4;11). De los 38 pacientes que remitieron, 10 recayeron (26,3 por ciento), fallecieron por infección 11/42 (26,2 por ciento). Ninguno falleció por otra toxicidad. La sobrevida libre de eventos global a 5 años fue 35 +/- 9 por ciento (mediana de seguimiento 50 meses), siendo similar en los diferentes protocolos usados (p = 0,61). Conclusión: Los pacientes evaluados con SD y LLA no presentaron factores clásicos de resistencia a tratamiento. No se observó mayor frecuencia de recaída respecto a los pacientes con LLA sin SD y la menor sobrevida en este grupo fue determinada por infecciones. Estos pacientes pueden ser tratados con los protocolos actuales pero requieren un manejo precoz e intensivo de las infecciones.

Calidad de vida en niños y adolescentes sobrevivientes de leucemia linfoblástica aguda / Quality of life in children and adolescents surviving acute lymphoblastic leukemia

Objective: Describe the quality of life of patients cured of acute lymphoblastic leukemia (ALL) treated at the Oncology Unit at Roberto del Rio Children's Hospital. Method: With a transversal design, the Kidscreen-27 questionnaire was applied to a selected sample of 41 patients. Results were compared with a random sample of school children paired for age and sex. Results: Children cured from ALL had lower scores than the control group, although ANOVA showed differences were not significant. ALL children tended to self report as ill, significantly lower in physical well-being. Average followup time was 8 years. Conclusions: Quality of life of chilean children cured from ALL is similar to school children of similar age and gender. To preserve the quality of life, it is suggested that the following measures be taken: prevention of sequelae, detection and treatment of emotional disorders, and discharge at a reasonable time.

Objetivo: Describir la calidad de vida relacionada con la salud en niños curados de LLA tratados en la Unidad de Oncología del Hospital de Niños Roberto del Río. Método: Bajo un diseño transversal, se aplicó el cuestionario específico Kidscreen-27 a una muestra intencionada de 41 pacientes. Con fines ilustrativos se compararon, mediante un ANOVA, los resultados obtenidos con datos de dos sub-muestras pareadas en edad y sexo, escogidas mediante proceso de randomización en una muestra de niños chilenos escolarizados evaluados con el mismo instrumento. Resultados: Los niños curados de LLA tuvieron medias inferiores (no significativo) a la de los grupos con que se compararon. En la muestra estudiada se observó mayor proporción de niños que se autoreportan como enfermos; en el ámbito del bienestar físico tienen una media significativamente inferior que los que se reportan sanos. El tiempo medio de control oncológico fue 8 años. Conclusiones: El auto-reporte de la calidad de vida de los niños curados de LLA es similar a una muestra de niños escolarizados chilenos. Para preservar la calidad de vida de los pacientes se sugiere que se realice prevención de secuelas, pesquisa y tratamiento de trastornos emocionales y alta definitiva en un plazo razonable.

The endocrine and local control of ovarian follicle development in the ewe

Follicle development can be divided into gonadotrophin-independent, gonadotrophin-responsive and gonadotrophin-dependent phases. The basic level of control of folliculogenesis lies with the actions of an extensively observed but poorly understood range of somatic and germ cell derived local factors that constitute an intrafollicular developmental cascade that regulates the proliferative and differentiative phases of follicle development. As follicle development progresses, the follicle become increasingly responsive to the actions of the pituitary gonadotrophins FSH and LH and during these phases of development local factors act to modulate the actions of gonadotrophins so that the fate of each follicle depends on an intrafollicular balance between local factors which augment or attenuate gonadotrophic actions. Gonadotrophins are therefore not a prerequisite for the continued growth of gonadotrophin-responsive pre-antral follicles, but FSH does appear to stimulate development and these actions are modulated by local growth factors, such as IGFs, AMH and BMPs. Naturally occurring mutations in sheep for a number of these factors or there receptors have provided insights into their roles during both the early and terminal stages of follicle development and we have recently produced extensive evidence supporting a major role for members of the BMP system in regulating follicle selection mechanisms through increased activation of gonadotrophic augmentors (BMP-6), decreased activation of attenuators (BMP-15, GDF-9, AMH) or a combination of these two mechanisms resulting in the deregulation of the normal follicle selection mechanisms. The terminal stages of follicle development, however, remain primarily under the control of the pituitary gonadotrophins, with both FSH and LH having essential and inter-related roles in regulating final maturation and selection of the ovulatory follicle and the oocyte which it contains.

The endocrine and local control of ovarian follicle development in the ewe

Follicle development can be divided into gonadotrophin-independent, gonadotrophin-responsive and gonadotrophin-dependent phases. The basic level of control of folliculogenesis lies with the actions of an extensively observed but poorly understood range of somatic and germ cell derived local factors that constitute an intrafollicular developmental cascade that regulates the proliferative and differentiative phases of follicle development. As follicle development progresses, the follicle become increasingly responsive to the actions of the pituitary gonadotrophins FSH and LH and during these phases of development local factors act to modulate the actions of gonadotrophins so that the fate of each follicle depends on an intrafollicular balance between local factors which augment or attenuate gonadotrophic actions. Gonadotrophins are therefore not a prerequisite for the continued growth of gonadotrophin-responsive pre-antral follicles, but FSH does appear to stimulate development and these actions are modulated by local growth factors, such as IGFs, AMH and BMPs. Naturally occurring mutations in sheep for a number of these factors or there receptors have provided insights into their roles during both the early and terminal stages of follicle development and we have recently produced extensive evidence supporting a major role for members of the BMP system in regulating follicle selection mechanisms through increased activation of gonadotrophic augmentors (BMP-6), decreased activation of attenuators (BMP-15, GDF-9, AMH) or a combination of these two mechanisms resulting in the deregulation of the normal follicle selection mechanisms. The terminal stages of follicle development, however, remain primarily under the control of the pituitary gonadotrophins, with both FSH and LH having essential and inter-related roles in regulating final maturation and selection of the ovulatory follicle and the oocyte which it contains.(AU)

Health human resource planning in Barbados and the eastern Caribbean states: a matter of sustainability.

Health and Human Resources (HHR) are very important issues to be considered in healthcare services. While various factors may be of greater significance in one area depending on resources, priorities and stage of economic development, a robust HHR plan is important in all cases. There are many factors such as demographic shifts, changing delivery models, consumer expectations, global shortages and financial restraints that must be considered in proper HHR planning. This manuscript summarizes some of the factors that should be considered and some of the short comings of current HHR planning approaches. Based on our review and experience, we developed a framework for HHR planning and apply the framework to Barbados to try to identify the existing challenges and issues and potential areas for staff and training investments.

Utilidad del factor estimulador de colonias de granulocitos (G-CSF) en episodios de neutropenia febril de alto riesgo en niños con cáncer / Usefulness of G-CSF in pediatric high risk cancer patients with fever and neutropenia

La neutropenia febril (NF) secundaria a quimioterapia es causa importante de morbilidad y mortalidad en los pacientes oncológicos pediátricos. El uso de factor estimulante de colonias de granulocitos (G-CSF) después de ciclos de quimioterapia intensa ha disminuido la frecuencia de complicaciones infecciosas asociadas, pero su utilización durante el episodio de NF es controvertida. Se analizaron 35 episodios de NF de alto riesgo. En forma randomizada 18 pacientes recibieron G-CSF asociado al tratamiento antimicrobiano habitual (grupo A) y 17 no lo recibieron (grupo B). Ambos grupos tenía parámetros biomédicos y clínicos similares. No se encontró diferencias significativas con respecto a la duración de la hospitalización (promedio grupo A 8 días vs grupo B 7 días) ni del tratamiento antimicrobiano (promedio 8 vs 7 días), de la fiebre (promedio 2 vs 3 días) y del período de neutropenia (promedio 3 vs 4 días). Considerando la revisión de la literatura y la experiencia local creemos que el uso de G-CSF no estaría recomendado en el manejo de pacientes oncológicos con episodios de NF.

[Usefulness of G-CSF in pediatric high risk cancer patients with fever and neutropenia]. / Utilidad del factor estimulador de colonias de granulocitos (G-CSF) en episodios de neutropenia febril de alto riesgo en niños con cáncer.

Chemotherapy associated febrile neutropenia is an important cause of morbidity and mortality in pediatric patients with cancer. The use of granulocyte-colony stimulating factor (G-CSF) post chemotherapy decreases the risk of infectious complications but its efficacy during the febrile neutropenic episode remains controversial. Thirty five episodes of high-risk febrile neutropenia were randomized into two treatment arms, 18 received antibiotics and G-CSF (group A) and 17 received antibiotics only upon admission (group B). Both groups were comparable in terms of demographic and clinical characteristics. No significant differences between groups were found in duration of hospitalization (mean group A 7 vs group B 8 days), antibiotic treatment (mean 7 vs 8 days), fever (3 vs 2 days), nor of neutropenia (4 vs 3 days). One patient in group A died after RSV infection. Considering these results and a literature review, we propose that G-CSF should not be recommended in children during the course of their febrile neutropenic episode.

Mechanisms of action of the principal prolific genes and their application to sheep production.

The prolificacy variation in sheep makes it an excellent animal model to understand the mechanisms regulating ovulation rate. Identification of mutations responsible for the increased prolificacy of the Inverdale, Booroola, Javanese, Cambridge and Belclare sheep open new avenues of investigation for the paracrine control of folliculogenesis. To date, all known mutations are in genes from ligands or receptors of the transforming growth factor beta superfamily, and point to the bone morphogenetic protein family of peptides as local regulators of ovarian follicle growth. The mechanism of action of the mutated genes is not fully understood, but results in the ovulation of a higher number of follicles with smaller diameter and fewer granulosa cells than that of the wildtype, thus speeding the differentiation of ovulatory follicles. Comparisons of the performance of Booroola-crossed flocks in different countries showed that carriers of the prolificacy mutation have higher ewe productivity but also higher perinatal mortality and lighter weight lambs. Their economic impact on the sheep industry depends on farm environment and management. Nevertheless, the diagnostic tests now available to identify the genetic mutations resulting in increased ovulation rate, will simplify the introduction of these mutations and their monitoring in flocks for research and commercial purposes.

Blood lead levels in Jamaican school children.

Blood lead levels are reported for a total of 421 schoolchildren in 13 schools in rural and urban environments in Jamaica, including one highly contaminated community. In the rural areas blood lead levels ranged from 3 to 28.5 microg dl(-1), with a median of 9.2 microg dl(-1); the range and median in the urban schools were 4-34.7 and 16.6 microg dl(-1), respectively. Forty-two percent of the rural and 71% of the urban blood lead levels exceeded the US Centers for Disease Control and Prevention intervention level of 10 microg dl(-1). Except in the contaminated area, the relationship between soil lead levels, which in Jamaica are in general typical of tropical lateritic soils, and blood lead levels is not clear-cut. Very high blood lead levels of 18 to > 60 microg dl(-1) with a median of 35 microg dl(-1) were observed among children in the contaminated area, the site of a former lead ore processing plant. These high blood lead levels were significantly reduced, by the implementation of relatively simple mitigation strategies which involved isolation of the lead, education, and a food supplementation programme, to levels similar to those observed in the urban schools. These values, however, remain higher than are desirable and unfortunately, all the sources of lead are not yet identified. The recent discontinuation of the use of leaded petrol is expected to result in significant reductions in exposure to lead.

Purification and characterization of an esterase conferring resistance to fenitrothion in Oryzaephilus surinamensis (L.) (insecta, coleoptera, silvanidae).

Esterases from a fenitrothion-resistant strain (VOSF) of the saw-toothed grain beetle, Oryzaephilus surinamensis (L.), are presumed to play a role in conferring resistance to malathion, fenitrothion, and chlorpyrifos-methyl. Colorimetric assays showed a significant positive correlation between increased resistance to fenitrothion in strains of O. surinamensis examined and elevated esterase hydrolytic activity to substrates of p-nitrophenyl acetate, alpha-naphthyl acetate, and beta-naphthyl acetate. Esterase zymograms showed different banding patterns between VOSF and an insecticide-susceptible strain, VOS48. A major esterase in the VOSF strain, not detected in VOS48, was purified and characterized by chromatographic and electrophoretic techniques. On the basis of SDS-polyacrylamide gel eletrophoresis, the molecular mass of the purified esterase from VOSF was 130 kDa and consisted of two 65 kDa subunits. Additional properties of this enzyme are discussed.

Estudios citogenéticos en niños chilenos con leucemia linfoblástica aguda / Cytogenetic studies in chilean children with acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) is the most frequent childhood cancer. The leukemic cells of ALL patients show several well defined numeric and structural chromosomal abnormalities which are universally known for its prognostic implications. We studied a group of 44 children with ALL, to investigate the incidence of chromosome aberrations in ALL, its lymphocyte lineage and some clinical feature associations, ans the finding of non previously described aberrations. A high proportion of patients (79.5 per cent) showed chromosomal abnormalities. Most of them had a pseudodiploid karyotype (46 chromosomes), characterized mainly by a translocation. In relation to chromosome number, 27 percent of them were hyperdiploid with more than 50; 9 percent hyperdiploid between 47 - 50 and 7 percent hypodiploid (less than 46). Among structural aberrations found, were the following recurrent translocations: t(1;19), t(4;11), t(9;22) in 6.8 percent, 9.1 percent and 2.3 percent of cases respectively, all related to an early B immunophenotype. Other translocations found, compromised regions 7q22,9p21 -24. Two new translocations in ALL were found: 8(1;5)(q23;q33), apparently balanced and t(13;21)(q14;q22), unbalanced. Other recurrent structural changes found were: deletion (6q), (7q), (7q), (11q), (12q), inversion (3q), isochromosome (7q), maker chromosomes and double minutes. The distribution of chromosome abnormalities in this group of patients was in agreement with previous reports from other investigators

Alta precoz de niños con cáncer y neutropenia febril / Early discharge of children with cancer and febrile neutropenia

Se describe una experiencia en 84 episodios de neutropenia febril, entre abril de 1992 y julio de 1993, en que se aplicó una conducta terapéutica diferenciada, con alta precoz a los niños de buena respuesta clínica, hemocultivos negativos y radiografía de tórax normal, aunque aún existiese neutropenia. En 30 episodios (35,7 por ciento) se suspendió el tratamiento con antibióticos y se dio el alta al niño, con un promedio de 5,1 días de estada, cuando todavía había neutropenia en 19 casos. En 17 episodios (20,2 por ciento) se suspendió el tratamiento endovenoso y se dio de alta al niño con antibióticos por vía oral, por existir un foco definido de infección, con un promedio de 6,1 días de estada y diez casos aún neutropénicos. En 37 episodios (44,1 por ciento) los pacientes fueron tratados intrahospitalariamente, por un promedio de 9,9 días de estada, porque sufrían de bacteremia, neumonia o fiebre prolongada, hasta la recuperación del número absoluto de neutrófilos. No se registraron reingresos de los pacientes neutropénicos en los siete días siguientes al egreso y no hubo fallecidos en la serie. Algunos pacientes con cancer y neutropenia febril, que cumplen condiciones para ser catalogados como de bajo riesgo, pueden ser dados de alta en forma precoz aun cuando persista la neutropenia

Neutropenia febril en niños con cáncer / Febrile neutropenia in children with cancer

El comienzo temprano y empírico de diversas combinaciones de antibióticos es obligatorio en niños con cáncer y neutropenia febril, debido a que las infecciones bacterianas son la causa más frecuente de morbilidad y mortalidad entre ellos. En una unidad de hematología y oncología se estudiaron entre mayo de 1988 y febrero de 1992, 149 episodios febriles que sucedieron en 84 niños con neutropenia (recuento absoluto de neutrófilos menos de 500 mm3). Los pacientes sufrían de leucemia linfocítica aguda (n=28), leucemia mieloide aguda (n=23) y otros tumores sólidos (n=23). Sus edades variaban entre 9 meses y 14 años 9 meses. Como tratameinto inicial se usó la combinación de cloxacilina con amikacina y cefoperazona. De los 149 episodios, 51 se observaron en leucemia linfática aguda, 45 en leucemia mieloide aguda y 53 en tumores sólidos. En 47,6 por ciento de los epidosios el diagnóstico final fue fiebre de origen desconocido; 22,1 por ciento neumonia aguda; 14,1 por ciento fueron considerados bacteremia o sepsis y 16,3 por ciento tenían infecciones clínicamente definidas (síndrome de diarrea aguda, tiflitis, infección urinaria, pielonefritis, celulitis, otitis y amigdalitis aguda). Las bacterias Gram positivas fueron las encontradas con mas frecuencia en los hemocultivos. El tratamiento inicial fue efectivo en 88,7 por ciento en los pacientes con fiebre de origen no precisado y en 78,3 por ciento de los niños con infección definida. La modificación de los antibióticos consistió en el empleo de ceftazimida en lugar de cefoperazona y en la adición de anfotericina B en ocho pacientes por posible sepsis por hongos. Todos los pacientes fueron tratados por siete o mas dias. La letalidad fue de 10,7 por ciento y las principales causas de muerte fueron neumonia, sepsis y tiflitis. La asociación de antibióticos usada parece adecuada para tratar a los pacientes con cancer que sufren neutropenia febril

You can be prepared when JCAHO visits.

Preparations for Joint Commission on Accreditation of Healthcare Organizations (JCAHO) surveys are rarely described in the literature. This article is intended to provide much-needed information on survey preparation processes, not only to Department of Veterans Affairs medical centers, but also to all hospitals undergoing surveys of biopsychosocial delivery of care. Beginning in 1995, JCAHO will apply biopsychosocial reviews to all assessments of patients. Facilities whose preparations include those detailed in this article will be better prepared for such reviews.

Carcinoma nasofaríngeo en la infancia / Nasopharyngeal carcinoma in childhood

Una paciente de 13 años, de sexo femenino, consultó por adenopatía cervical bilateral, coriza y disfonía de un mes de duración, sin fiebre ni otras manifestaciones, no respondió a tratamiento empírico con antibióticos, agregándose luego desplazamiento de la úvula y prominencia de la amígdala derecha. La punción, la biopsia, las radiografías de tórax y huesos y la tomografía axial demostraron que se trataba de un carcinoma nasofaríngeo en estadio IV, las pruebas serológicas fueron positivas para infección previa por virus Epstein Barr. La niña fue tratada con radioterapia con buenos resultados, pero tuvo una adenopatía persistente, la que respondió bien a la quimioterapia posterior. Esta neoplasia tiene una baja incidencia en la edad pediátrica, clínicamente se presenta con adenopatías cervicales de larga evolución y síntomas respiratorios altos persistentes

Tumor de Wilms / Wilms tumor

El prognóstico del Tumor de Wilms ha mejorado notablemente al agregar a la cirugía quimioterapia y radioterapia agresivas. Se analizan 24 casos de Tumor de Wilms tratados en el Hospital Roberto del Río entre 1978 y 1989. 14 eran mujeres y 10 hombres. El promedio de edad fue 3 años y 7 de ellos eran menores de 1 año. El signo clínico más frecuente fue aumento de volumen abdominal; en un tercio de los casos este hallazgo fue hecho por la madre o en un examen de salud (control de niño sano). En todos los niños se realizó nefrectomía y quimioterapia. En 3, además se hizo Q.T. preoperatoria y en 6 radioterapia además de cirugía y quimioterapia. La sobrevida, (tiempo de observación de 8 meses a 12 años con una mediana de 3 años) fue de 71%

A new Huffmanela species, H. schouteni sp. n. (Nematoda: Trichosomoididae) from flying fishes in Curaçao.

A new nematode species, Huffmanela schouteni sp. n., has been established on the basis of its egg morphology and biological characters (adult nematodes are unknown). The dark-shelled eggs of this histozoic parasite occur in masses in the abdominal cavity, serose covers of internal organs and in the liver of the flying fishes Hirundichthys affinis Günther (type host) and Cypselurus cyanopterus Cuvier et Valenciennes in Curaçao. The eggs of H. schouteni sp. n. differ from those in other congeneric species mainly in the absence of small spines on the surface of the transparent envelope enclosing the egg proper, measurements (size of eggs 0.069-0.075 x 0.027-0.030 mm) and their localization in the host. A key to Huffmanela species based on egg morphology has been provided.

Tumores abdominales en el niño: tratamiento quirúrgico / Abdominal tumors in the child: surgical treatment

Se efectuó un estudio retrospectivo de niños operados con el diagnóstico de tumor abdominal maligno en el Hospital Roberto del Río desde 1978 a 1987. Se encontró 56 pacientes. Se excluyó las metástasis de los tumores de otras localizaciones. El análisis fue hecho según los diagnósticos anatomopatológicos, encontrándose una amplia gama de tumores, de los cuales los más frecuentes fueron los linfomas (24), tumor de Wilms (14) y rabdomiosarcomas (6). Se postula una cirugía más conservadora por tratarse de niños en que el desarrollo posterior para llevar una vida útil es importante, teniendo en cuenta además que la quimioterapia ha demostrado ser efectiva en la mayoría de estos tumores para permitir efectuar una segunda intervención e ir a la resección completa. Aunque esta casuística es escasa, se estima importante analizarla, ya que los tumores de iniciación abdominal plantean un problema para el cirujano pediatra, especialmente cuando son intervenidos de urgencia