Tumores neuroendocrinos: Experiencia interdisciplinaria del hospital privado de comunidad / Neuroendocrine tumors: Interdisciplinary experience of the Private Community Hospital

Resumen Los tumores neuroendocrinos (TNE) constituyen un grupo heterogéneo de neoplasias poco frecuentes con un aumento sostenido de la incidencia en los últimos años. Se originan en las células neuroendocrinas, los más frecuentes son los del sistema gastrointestinal y la mayoría son esporádicos, aunque pueden ser parte de síndromes hereditarios. El manejo de esta patología es interdisciplinario y el endocrinólogo tiene un rol activo en estos grupos. Evaluamos retrospectivamente pacientes con diagnóstico de TNE en un periodo de 18 años (01/01/2000 al 31/12/2017). Ciento cinco pacientes presentaron TNE, la edad promedio al momento del diagnóstico fue de 57,6 años y predominó el sexo femenino (64%). Predominaron los de origen gastroenteropancreático (TNEGEP) bien diferenciados y de bajo grado, el 39% se presentó con metástasis al momento del diagnóstico, el 11% de ellos fueron funcionantes (gastrinoma e insulinomas), el 17% presento síndrome carcinoide, el 94% de ellos recibió algún tipo de tratamiento y el 29% recibió análogos de somatostatina (ASS). No hubo diferencia en la cantidad de casos entre el carcinoma medular de tiroides (dos de ellos con NEM-2) y los broncopulmonares donde predominó el carcinoide típico. Los TNE tímicos fueron de gran tamaño y uno de ellos como parte de NEM -1. Los feocromocitomas fueron esporádicos, unilaterales y curaron con la cirugía y los de origenovárico fueron menos frecuentes. Conclusiones: La incidencia de los TNE está en aumento en todo el mundo, se presentan alrededor de la sexta década, sin predominancia de género y la mayoría son esporádicos. Nuestra casuística tiene la limitación de ser un trabajo retrospectivo que incluye casi dos décadas y donde la clasificación de los TNE ha sufrido grandes cambios. Sin embargo, no existe en la literatura argentina una serie con mayor número de casos reportados por una única institución, de una patología poco frecuente y constituye un significativo aporte a la epidemiología de estos tumores en nuestro país.

Abstract One hundred and five patients were diagnosed with NETs. The mean age of presentation was 57.6 years (R: 18/86). Patients were predominantly female (64%), with an increase in presentation of 50% in recent years. Well differentiated, low-grade GEPNETs were predominant. Metastases at the time of diagnosis were seen in 39% of patients. In 11% of them, tumors were functional (gastrinoma and insulinomas). Carcinoid syndrome was present 17% of the patients and 29% received somatostatin analogues (AS). There were no differences presentation between medullary thyroid carcinoma (two of them were part of a MEN-2 syndrome) and those of bronchopulmonary localization, where the typical carcinoid predominated. Thymic NETs were frequently large at diagnosis and in one patient, the tumor was part of a MEN-1 syndrome. Pheochromocytomas were sporadic, unilateral and were cured with surgery. The ovarian were the least common in our series.

Membrane hyperpolarization during human sperm capacitation.

Sperm capacitation is a complex and indispensable physiological process that spermatozoa must undergo in order to acquire fertilization capability. Spermatozoa from several mammalian species, including mice, exhibit a capacitation-associated plasma membrane hyperpolarization, which is necessary for the acrosome reaction to occur. Despite its importance, this hyperpolarization event has not been adequately examined in human sperm. In this report we used flow cytometry to show that a subpopulation of human sperm indeed undergo a plasma membrane hyperpolarization upon in vitro capacitation. This hyperpolarization correlated with two other well-characterized capacitation parameters, namely an increase in intracellular pH and Ca(2+) concentration, measured also by flow cytometry. We found that sperm membrane hyperpolarization was completely abolished in the presence of a high external K(+) concentration (60 mM), indicating the participation of K(+) channels. In order to identify, which of the potential K(+) channels were involved in this hyperpolarization, we used different K(+) channel inhibitors including charybdotoxin, slotoxin and iberiotoxin (which target Slo1) and clofilium (a more specific blocker for Slo3). All these K(+) channel antagonists inhibited membrane hyperpolarization to a similar extent, suggesting that both members of the Slo family may potentially participate. Two very recent papers recorded K(+) currents in human sperm electrophysiologically, with some contradictory results. In the present work, we show through immunoblotting that Slo3 channels are present in the human sperm membrane. In addition, we found that human Slo3 channels expressed in CHO cells were sensitive to clofilium (50 µM). Considered altogether, our data indicate that Slo1 and Slo3 could share the preponderant role in the capacitation-associated hyperpolarization of human sperm in contrast to what has been previously reported for mouse sperm, where Slo3 channels are the main contributors to the hyperpolarization event.

Accelerator-based BNCT.

The activity in accelerator development for accelerator-based BNCT (AB-BNCT) both worldwide and in Argentina is described. Projects in Russia, UK, Italy, Japan, Israel, and Argentina to develop AB-BNCT around different types of accelerators are briefly presented. In particular, the present status and recent progress of the Argentine project will be reviewed. The topics will cover: intense ion sources, accelerator tubes, transport of intense beams, beam diagnostics, the (9)Be(d,n) reaction as a possible neutron source, Beam Shaping Assemblies (BSA), a treatment room, and treatment planning in realistic cases.

Arritmia fatal secundaria a hiperpotasemia asintomática y sin alteración inicial electrocardiográfica / No disponible

La hiperpotasemia es una alteración hidroelectrolítica frecuente en lospacientes hospitalizados. Presentamos a continuación el caso de unapaciente oncológica con hiperpotasemia asintomática y sin alteracioneselectrocardiográfi cas que presentó a las pocas horas una parada cardíaca.Se revisa el manejo diagnóstico y terapéutico actualmente recomendadopara controlar este desequilibrio potencialmente mortal. Debería realizarseun control frecuente de las cifras de potasemia aunque el pacienteesté asintomático y sin alteraciones electrocardiográfi cas(AU)

Hyperpotassemia is a common hydroelectrolytic disturbance in hospitalizedpatients. We report herein the case of an asymptomatic oncologicalpatient with no electrocardiographic alterations who suffered cardiacarrest. We review the diagnosis of this life-threatening complication andtherapeutic approaches. Blood potassium levels should be measuredfrequently, even if patients are asymptomatic or show no electrocardiographicdisorders(AU)

Arritmia fatal secundaria a hiperpotasemia asintomática y sin alteración inicial electrocardiográfi ca / Fatal arrhythmia caused by asymptomatic hypeerkalemia with normal basal electrocardiogram

La hiperpotasemia es una alteración hidroelectrolítica frecuente en los pacientes hospitalizados. Presentamos a continuación el caso de una paciente oncológica con hiperpotasemia asintomática y sin alteracioneselectrocardiográficas que presentó a las pocas horas una parada cardíaca. Se revisa el manejo diagnóstico y terapéutico actualmente recomendado para controlar este desequilibrio potencialmente mortal. Debería realizarseun control frecuente de las cifras de potasemia aunque el paciente esté asintomático y sin alteraciones electrocardiográficas

Hyperpotassemia is a common hydroelectrolytic disturbance in hospitalized patients. We report herein the case of an asymptomatic oncological patient with no electrocardiographic alterations who suffered cardiacarrest. We review the diagnosis of this life-threatening complication and therapeutic approaches. Blood potassium levels should be measured frequently, even if patients are asymptomatic or show no electrocardiographicdisorders

Alkaline pH and internal calcium increase Na+ and K+ effluxes in LK sheep red blood cells in Cl--free solutions.

We examined the effects of pH, internal ionized Ca (Ca2+i), cellular ATP, external divalent cations and quinine on Cl-independent ouabain-resistant K+ efflux in volume-clamped sheep red blood cells (SRBCs) of normal high (HK) and low (LK) intracellular K+ phenotypes. In LK SRBCs the K+ efflux was higher at pH 9.0 (350%) than at pHs 7. 4 and 6.5, and was inhibited by external divalent cations, quinine, and cellular ATP depletion. The above findings suggest that the increased K+ efflux at alkaline pH is due to the opening of ion channels or specific transporters in the cell membrane. In addition, K+ efflux was activated (100%) when Ca2+i was increased (+A23187, +Ca2+o) into the microm range. However, in comparison to human red blood cells, the Ca2+i-induced increase in K+ efflux in LK SRBCs was fourfold smaller and insensitive to quinine and charybdotoxin. The Na+ efflux was also higher at pH 9.0 than at pH 7.4, and activated (about 40%) by increasing Ca2+i. In contrast, in HK SRBCs the K+ efflux at pH 9.0 was neither inhibited by quinine nor activated by Ca2+i. These studies suggest the presence in LK SRBCs, of at least two pathways for Cl--independent K+ and Na+ transport, of which one is unmasked by alkalinization, and the other by a rise in Ca2+i.

Modulation of K-Cl cotransport in volume-clamped low-K sheep erythrocytes by pH, magnesium, and ATP.

Cellular pH, ionized Mg (Mgi2+), and MgATP concentration of red blood cells, concomitantly with cell volume, change transiently during circulation. The action of these three effectors on Cl-dependent K efflux was examined in low-K sheep red blood cells with constant cell volume. Activation of K-Cl efflux by Mgi2+ extraction required ATP, suggesting that phosphorylation of a putative component occurred before Mgi2+ extraction. Conversely, Mg and ATP were synergistic inhibitors of K-Cl cotransport, since maximal inhibition was observed only in cells containing both ATP and > 300 microM Mgi2+. Both findings suggest dual roles for Mg and ATP. At 300-600 microM Mgi2+, lowering the pH from approximately 7.4 to approximately 6.5 stimulated K-Cl efflux only in fed cells, suggesting that protons oppose or release the inhibition by Mgi2+ and ATP. A direct effect of both protons and Mgi2+ on the cotransporter is suggested by their inhibition of K-Cl efflux in ATP-depleted cells. These findings are discussed in light of the current phosphorylation/dephosphorylation hypothesis.

Activation of bovine neutrophils by Pasteurella haemolytica leukotoxin is calcium dependent.

In this study, we used the fluorescent probe Fluo-3 to show that an increase in cytosolic free calcium, [Ca2+]i, occurred when suspensions of bovine neutrophils were incubated with sublethal concentrations of P. haemolytica leukotoxin. This increase in [Ca2+]i was dependent on the concentration of leukotoxin present in the medium and, at a given concentration of leukotoxin, dependent on the external calcium concentration. The calcium channel blocker verapamil and the beta-adrenergic antagonist propranolol inhibited leukotoxin-stimulated Ca2+ gain, as did a neutralizing antileukotoxin monoclonal antibody. As reported previously, incubation of bovine neutrophils with partially purified leukotoxin stimulated a vigorous luminol-dependent chemiluminescence response (LDCL). The present study shows that LDCL stimulation was dependent on the presence of extracellular calcium and was inhibited by the addition of verapamil and propranolol. These data indicate that bovine neutrophils exhibit a considerable increase in cytoplasmic free calcium when they are incubated with P. haemolytica leukotoxin in the presence of external calcium. They also provide evidence that an increased [Ca2+]i is required for functional activation of the bovine neutrophil oxidative burst by P. haemolytica leukotoxin.

Pasteurella haemolytica leukotoxin inhibits mitogen-induced bovine peripheral blood mononuclear cell proliferation in vitro.

In this study we demonstrate that partially purified Pasteurella haemolytica leukotoxin inhibits the proliferative response of bovine peripheral blood mononuclear cells (PBMC) to mitogens in vitro. Inhibition of PBMC proliferation did not appear to be due to cell death. Addition of a neutralizing anti-leukotoxin monoclonal antibody restored a normal proliferative response.

Activation of bovine neutrophils by partially purified Pasteurella haemolytica leukotoxin.

In this study we developed a new method for the partial purification of Pasteurella haemolytica leukotoxin by size-exclusion high-performance liquid chromatography. The partially purified leukotoxin had a molecular weight of 104,000, as estimated by using sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and reacted on an immunoblot with an antileukotoxin monoclonal antibody. As expected, high concentrations of the leukotoxin were inhibitory or lethal to bovine neutrophils. Incubation of bovine neutrophils with diluted leukotoxin, however, resulted in significant neutrophil activation that was comparable in magnitude to that obtained with standard activating agents such as opsonized zymosan or zymosan-activated serum. Dilute leukotoxin (1:128 to 1:8,192 dilutions) stimulated an oxidative burst (luminol-dependent chemiluminescence) by bovine neutrophils that was comparable in magnitude to that obtained with opsonized zymosan. Preincubation with leukotoxin did not significantly prime the neutrophils for an enhanced oxidative burst when they were then exposed to opsonized zymosan as a second stimulus. Dilute leukotoxin (1:100 to 1:1,000 dilutions) also stimulated cytoskeletal alterations in bovine neutrophils, as measured by a significant shape change response. Preferential release of secondary granule constituents (lactoferrin) occurred when neutrophils were incubated with 1:100 to 1:500 dilutions of leukotoxin. Significant release of primary granules, as measured by beta-glucosaminidase activity, was not observed except at low dilutions (1:20) of leukotoxin that resulted in significant release of cytosolic constituents (i.e., lactate dehydrogenase activity). The neutrophil-activating activity of the leukotoxin was heat labile, unaffected by polymyxin B, and abrogated by a leukotoxin-neutralizing monoclonal antibody. These data indicate that P. haemolytica leukotoxin, like the closely related Escherichia coli hemolysin, is a potent neutrophil-activating agent. Leukotoxin-stimulated release of neutrophil oxygen intermediates and granule constituents may contribute to the intense inflammation that characterizes bovine pulmonary pasteurellosis.