ABSTRACT
Los tumores benignos del bazo como los quistes esplénicos y las esplenomegalias per se no representan un peligro para los pacientes portadores de estas raras lesiones; sin embargo tienen un riesgo potencial de crecer y lograr dimensiones que pueda originar complicaciones tales como rotura, producir una hemorragia intraperitoneal o infectarse. A continuación reportamos dos pacientes con bazo gigante, síntomas abdominales inespecíficos y que fueron tratados con cirugía. El primer caso es un paciente con quiste esplénico; histológicamente se caracteriza por la presencia de epitelio escamoso en su pared que condiciona una producción importante, en algunos casos del marcador tumoral CA 19.9 que ha sido descrito en varios trabajos recientes. El segundo caso es un paciente con un gran hiperesplenismo de 26cm de diámetro máximo, y dolor abdominal. En estos pacientes la microscopía muestra frecuentemente infiltración a diferentes niveles, según su enfermedad, de variados elementos que pueden ser desde células benignas como las enfermedades hiperplásicas del sistema reticuloendotelial, células malignas como en las leucemias y linfomas , enfermedades por depósito, o por infiltración en las que se agrupan a las histiocitosis, como es el segundo caso que presentamos. El tratamiento para bazos grandes, generalmente mayores de 13cm de diámetro y con sintomatología, es el quirúrgico y específicamente la esplenectomía total, pues la presencia de restos de la pared del quiste con otras técnicas más conservadoras parece llevar inexorablemente a la recurrencia de la enfermedad, así mismo cirugías conservadoras en hipertrofia o hiperesplenismo sólo perpetuarán la enfermedad de base.
Spleen benign tumors such as splenic cyst and splenomegaly do not represent a danger to patients with these uncommon injuries. However, they potentially risk growing and reaching dimensions that can cause complications such as rupture, producing an infection or intraperitoneal hemorrhage. Here we report two patients with giant spleens, and nonspecific abdominal symptoms which were treated with surgery. The first case was a patient with splenic cyst, histologically characterized by the presence of squamous epithelium in its wall that, in some cases, induces an important production of the tumor marker CA 19.9, which has been described in several recent works. The second case was a patient with a big hypersplenism of about 26 cm in diameter, and abdominal pain. Microscopy in these patients often shows infiltration at different levels, depending on their disease, of various elements ranging from benign cells such as hyperplasic diseases of the reticuloendotheleal system, malignant cells as in the leukemia and lymphoma, abnormal inclusion diseases, or by infiltration, which include the histiocytosis, as in the second case previously presented. The treatment for large spleens, usually over 13 cm in diameter and with symptomatology, is the surgery, and specifically the total splenectomy, because the presence of residues of the cyst wall with other more conservative techniques seem to lead to the recurrence of the disease. Furthermore, conservative surgery in hypersplenism or hypertrophy will only perpetuate the original disease of patients.
Subject(s)
Male , Young Adult , Splenomegaly/etiology , Splenectomy , Splenic NeoplasmsABSTRACT
Calcium channel activity is crucial for many fundamental physiological processes ranging from the heart beat to synaptic transmission. The channel-forming protein, of about 2000 amino acids, comprises four domains internally homologous to each other. Voltage-dependent Ca2+ channels are the most selective ion channels known. Under physiological conditions, they prefer Ca2+ over Na+ by a ratio of about 1000:1. To explain at the same time the exquisite ion selectivity and the large Ca2+ ion turnover rate of Ca2+ channels (~ 3x10(6) ions/s), two kind models have been proposed. In one, the conduction pathway possesses two high-affinity binding sites. When two Ca2+ ions are bound to each site, the mutual repulsion between them speeds the exite rate for the ions, causing greater ion permeation through the pore. The second model hypothesizes the existence of a single site having a charged structure able to attract multiple, interacting ions, simultaneously. Recent studies that combine mutagenesis and electrophysiology show that the high-affinity binding site is formed by a ring of glutamate residues located in the pore forming region of the Ca2+ channel. As proposed in the second class of models, the results suggest that four glutamate residues, one glutamate donated by each repeat, combine to form a single high-affinity site. In this review the different conduction models for Ca2+ channels are discussed and confronted with structural data.