Fístula aortoentérica secundaria: revisión de la literatura a propósito de un caso / No disponible

Las fistulas aortoentéricas constituyen una complicación grave de la cirugía protésica por su elevada morbi-motalidad. La forma de presentación clínica más frecuente es en forma de hemorragia digestiva alta masiva, hipotensión y shock. No obstante, en algunos casos las manifestaciones clínicas aparecen en forma de fiebre y molestias abdominales poco específicas que permiten realizar su diagnóstico. La tomografía axial computerizada y la fibrogastroscopia constituyen los estudios diagnósticos de elección por su elevada resolución. El tratamiento debe ser siempre quirúrgico, con la resección de la prótesis en su totalidad, ligadura de la arteria aorta a nivel infrarrenal, revascularización de las extremidades mediante un bypass axilo-bifemoral y extirpación del segmento de intestino delgado perforado (AU)

Aortoenteric fistulas are an important complication of protesic surgery due to their high morbidity an mortality. The most frequent form of clinical manifestation is the massive upper gastrointestinal bleeding, hypotension and shock. However, in some cases the feber and the abdominal pain may be the only manifestation. The computerized tomography and the oral endoscopy are the most useful complementary techniques. Treatment almost always requires excision of the infected graft and revascularization with an extra anatomic bypass followed by perforated duodenum excision (AU)

Electrical measurement of the absorption surfaces of tree roots by the earth impedance method: 1. Theory.

Analysis of plant root systems is difficult under field conditions, especially root systems of adult trees, which are large and complex and include fine absorbing roots as well as conducting coarse roots. Although coarse roots can be visualized by several methods, there are technical difficulties with root quantification. The method presented here focuses on the quantification of absorbing root surfaces through an electrical (the modified earth impedance) method. It is based on the experimentally verified fact that an applied electric current flows from the roots to the soil (or vice versa) through the same interfacial areas and predominantly in the same way as water (water solution of minerals or nutrients) flows from the soil to the tree. Based on the different conductivities of tree tissues and soil, the interfacial area, which represents the absorbing root surfaces (or root absorption zones), can be calculated. Only the theoretical description of the method is presented in this paper: the experimental verification of the method under field conditions is presented in the accompanying paper.

Electrical measurement of tree root absorbing surfaces by the earth impedance method: 2. Verification based on allometric relationships and root severing experiments.

We validated, by means of allometric relationships and root severing experiments, the modified earth impedance method developed for measuring absorbing root surfaces. For the allometric studies, a series of 350 small and large trees of six broadleaf and coniferous species in several experimental sites was examined. We found a good linear ln-ln fit between absorbing root surface area and basal area (or stem cross-sectional area at the root collar in seedlings) over a range of stem diameters from 0.5-55 cm. The absorbing root surface area also changed consistently with crown projected area and the root-accessed area (territory) of the tree. At the whole-tree level, absorbing root surface area reached about 70 times that of basal area and 40% of crown projected area, or roughly 1/3 of the root-accessed area in Norway spruce (in this species, the ratio was relatively larger in small trees and smaller in large trees). The absorbing root surfaces of mechanically severed parts of Norway spruce root systems changed in about the same proportions as the geometrically determined parts of the severed root systems. These results are promising and support field applications of the method in biological and ecological studies.

Division of lymphatic vessels at varicocelectomy leads to testicular oedema and decline in testicular function according to the LH-RH analogue stimulation test.

OBJECTIVES: To study the andrological outcome of the division of testicular lymphatic vessels at varicocelectomy in children and adolescents. METHODS: Testicular size and basal and stimulated luteinizing hormone (LH) and follicle-stimulating hormone (FSH) values were determined prospectively in 86 patients with left unilateral varicocele grades II-III. 22 patients underwent lymphatic non-sparing surgery (LNS group), 10 of them with artery sparing (LNS/AS) and 12 without artery sparing (LNS/ANS), 23 patients underwent lymphatic sparing repair (LS group) and 41 patients were treated conservatively (NT group). RESULTS: The LNS group demonstrated significantly greater left testicular enlargement at six weeks and one year following repair, left testicular hypertrophy developed in 31.8% and hydrocele in 22.7% of patients. Marked oedema of intertubular tissue and a varying degree of tubular injury was observed in boys surgically treated for hydrocele. In the LS group, neither hypertrophy nor hydrocele developed postoperatively, the LH stimulated values were lower than in LNS/ANS group (p<0.05) and the NT group (p<0.04), the FSH stimulated values were lower than in the LNS/ANS group (p<0.001). CONCLUSIONS: Division of lymphatic vessels at varicocelectomy is associated with an excessive increase in testicular volume due to oedema, and with a reduced testicular function according to higher LH and FSH stimulated values. Preservation of lymphatics is strongly advised in varicocelectomy in adolescents to ensure better andrological outcome.