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.

Fc epsilon RI-mediated association of 6-micron beads with RBL-2H3 mast cells results in exclusion of signaling proteins from the forming phagosome and abrogation of normal downstream signaling.

Cells of the mucosal mast cell line, RBL-2H3, are normally stimulated to degranulate after aggregation of high affinity receptors for IgE (Fc epsilon RI) by soluble cross-linking ligands. This cellular degranulation process requires sustained elevation of cytoplasmic Ca2+. In this study, we investigated the response of RBL-2H3 cells to 6-micron beads coated with IgE-specific ligands. These ligand-coated beads cause only small, transient Ca2+ responses, even though the same ligands added in soluble form cause larger, more sustained Ca2+ responses. The ligand-coated 6-micron beads also fail to stimulate significant degranulation of RBL-2H3 cells, whereas much larger ligand-coated Sepharose beads stimulate ample degranulation. Confocal fluorescence microscopy shows that the 6-micron beads (but not the Sepharose beads) are phagocytosed by RBL-2H3 cells and that, beginning with the initial stages of bead engulfment, there is exclusion of many plasma membrane components from the 6-micron bead/cell interface, including p53/56lyn and several other markers for detergent-resistant membrane domains, as well as an integrin and unliganded IgE-Fc epsilon RI. The fluorescent lipid probe DiIC16 is a marker for the membrane domains that is excluded from the cell/bead interface, whereas a structural analogue, fast DiI, which differs from DiIC16 by the presence of unsaturated acyl chains, is not substantially excluded from the interface. None of these components are excluded from the interface of RBL-2H3 cells and the large Sepharose beads. Additional confocal microscopy analysis indicates that microfilaments are involved in the exclusion of plasma membrane components from the cell/bead interface. These results suggest that initiation of phagocytosis diverts normal signaling pathways in a cytoskeleton-driven membrane clearance process that alters the physiological response of the cells.

Sphingomyelinase treatment induces ATP-independent endocytosis.

ATP hydrolysis has been regarded as a general requirement for internalization processes in mammalian cells. We found, however, that treatment of ATP-depleted macrophages and fibroblasts with exogenous sphingomyelinase (SMase) rapidly induces formation of numerous vesicles that pinch off from the plasma membrane; the process is complete within 10 min after adding SMase. By electron microscopy, the SMase-induced vesicles are approximately 400 nm in diameter and lack discernible coats. 15-30% of plasma membrane is internalized by SMase treatment, and there is no detectable enrichment of either clathrin or caveolin in these vesicles. When ATP is restored to the cells, the SMase-induced vesicles are able to deliver fluid-phase markers to late endosomes/lysosomes and return recycling receptors, such as transferrin receptors, back to the plasma membrane. We speculate that hydrolysis of sphingomyelin on the plasma membrane causes inward curvature and subsequent fusion to form sealed vesicles. Many cell types express a SMase that can be secreted or delivered to endosomes and lysosomes. The hydrolysis of sphingomyelin by these enzymes is activated by several signaling pathways, and this may lead to formation of vesicles by the process described here.

Cytoskeleton-dependent membrane domain segregation during neutrophil polarization.

On treatment with chemoattractant, the neutrophil plasma membrane becomes organized into detergent-resistant membrane domains (DRMs), the distribution of which is intimately correlated with cell polarization. Plasma membrane at the front of polarized cells is susceptible to extraction by cold Triton X-100, whereas membrane at the rear is resistant to extraction. After cold Triton X-100 extraction, DRM components, including the transmembrane proteins CD44 and CD43, the GPI-linked CD16, and the lipid analog, DiIC(16), are retained within uropods and cell bodies. Furthermore, CD44 and CD43 interact concomitantly with DRMs and with the F-actin cytoskeleton, suggesting a mechanism for the formation and stabilization of DRMs. By tracking the distribution of DRMs during polarization, we demonstrate that DRMs progress from a uniform distribution in unstimulated cells to small, discrete patches immediately after activation. Within 1 min, DRMs form a large cap comprising the cell body and uropod. This process is dependent on myosin in that an inhibitor of myosin light chain kinase can arrest DRM reorganization and cell polarization. Colabeling DRMs and F-actin revealed a correlation between DRM distribution and F-actin remodeling, suggesting that plasma membrane organization may orient signaling events that control cytoskeletal rearrangements and, consequently, cell polarity.

Mirada de la población adolescente sobre aspectos bioéticos en el paciente crítico: un estudio en 848 jóvenes escolarizados / Look at the population teenager about aspects bioethics in the critical patient: a study in 848 young people schooled

Objetivos: Cuantificar donantes, personas que aceptan tratamientos invasivos, que firmarían órdenes de no reanimar, que avalarían transfusiones a personas contra su voluntad, que aceptan el aborto, la eutanasia y la investigación experimental, en todos los casos vinculando la respuesta con fundamentaciones. Materiales y Métodos: Diseño prospectivo, de observación, longitudinal, analítico. En 2007-2008, se estudiaron 848 adolescentes de 13 escuelas públicas de enseñanza media del área de responsabilidad de un hospital del Gobierno de la Ciudad Autónoma de Buenos Aires, en quienes se aplicó una encuesta autoadministrada abierta-cerrada. Se interrogó sobre situaciones vinculadas a aspectos bioéticos. Resultados: Los donantes representan el 75% de la muestra, el 46% desea que le implementen todo tratamiento posible, el 30% firmaría una orden de no reanimación, el 32% avala las transfusiones a Testigos de Jehová, el 57% acepta el aborto; el 81%, la eutanasia; el 62%, la investigación experimental. No hay diferencias de aceptación del aborto y la eutanasia entre católicos y no creyentes (p 0,10 y 0,30, respectivamente). En el análisis multivariado, la implementación de todo tipo de tratamiento se vinculó a no firmar una orden de no reanimar (p 0,0000) y a no respetar la voluntad de los Testigos de Jehová (p 0,0024). La aceptación de la eutanasia se vincula con la aceptación de aborto (p 0,0000) y firmar una orden de no reanimar (p 0,0266). Conclusiones: Los valores más votados fueron la veracidad y la justicia. La escuela media es un sitio de alto impacto para educar en bioética y derechos de ciudadanía(AU)

Objectives: To quantify donors, people who would accept invasive treatments, who would sign orders not to resuscitate, who would support transfusions to persons against their will, who would accept abortion, euthanasia, and experimental research, in all cases supporting their choices with foundations. Materials and Methods: Prospective, observational, longitudinal and analytical study. During 2007-2008, 848 teenagers belonging to 13 public high schools in the area of responsibility of a hospital from Gobierno de la Ciudad Autónoma de Buenos Aires were studied. They were given a self-administered opened-closed survey which included questions about situations linked to bioethical aspects. Results: Donors represent 75% of the sample, 46% wish to get any possible treatment, 30% would sign a do-not-resuscitate order, 32% support transfusions to Jehovah's Witnesses, 57% accept abortion, 81% euthanasia, 62% experimental research. There are no differences on acceptance of abortion and euthanasia between Catholics and non-believers (p 0.10 and 0.30, respectively). In the multivariate analysis, the implementation of all kinds of treatment was linked to a refusal to sign a do-not-resuscitate order (p 0.0000) and to not respecting the will of the Jehovah's Witnesses (p 0.0024). The acceptance of euthanasia links itself, in the analysis multivariate, to accepting abortion (p 0.0000) and to signing a do-not-resuscitate order (p 0.0266). Conclusions: The majority vote in favor of veracity and justice. High school is a high impact point to educate on bioethics and rights of citizenship(AU)

Teenager donation: investigation of 848 high school students.

AIMS: The aims of this study were to quantify donors among the investigated area, quantify arguments and myths about the donation and transplantation process, and fix predetermined donation variables in a logistical model. MATERIALS AND METHODS: We used an analytical, prospective design, using 848 students from 13 high schools in the Velez Sarsfield Hospital area in an open-closed inquiry. RESULTS: Females were 57.74% and average age was 16.64 +/- 0.06 years, including 65.09% Catholics. The 642 potential donors represented 75% of the study population with the fundamental aim being to "give life" (44.85%). The 193 (22.75%) opposed subjects cited as a principal reason fear and distrust (40.41%). There were 40.21% who had discussed the donation subject with their families. In our study 76.41% believed that human organ traffic exists and 36.88% thought that it is due to corruption. Also, 56.01% fear premature extraction of their organs. In addition, 73.23% of teenagers considered that individuals who refused to donate have the right to receive organs (P = not significant between donors and not a donor). The family discussion and the lack of fear about premature extraction were donation signals. About the low level of donation 43.27% blamed the government (lack of campaigns, information, and knowledge) whereas other reasons were fear, lack of clarity and distrust. In our study 49.17% seemed to wish to increase donation if they received more information. CONCLUSIONS: Individuals predispose to donation represented the great majority of the queried teenagers; education and family discussion were remarkable factors favoring the decision.

Spatial and temporal sequence of capsule construction in Cryptococcus neoformans.

The pathogenic yeast Cryptococcus neoformans is distinguished by an extensive polysaccharide capsule, which impedes host defences and is absolutely required for fungal virulence. Despite the biological importance of the capsule, nothing is known about how it is assembled. Substantial capsule growth occurs in two distinct situations relevant to cryptococcal pathogenesis: formation of new buds and induction of capsule on mature cells. We developed pulse-chase protocols to examine these events in a dynamic way using a variety of microscopy techniques. We show that the capsule overlying buds is newly synthesized and differs physically from the corresponding parental material. New capsule formed by mature cells upon induction of synthesis is added at the inner aspect of the existing structure, displacing pre-existing material outwards. Surprisingly, new polysaccharide material is also deposited throughout the capsule, yielding a progressively denser structure. These results yield the first model of capsule synthesis and open new lines of investigation into the underlying mechanisms.

Evidence supporting a role for microfilaments in regulating the coupling between poorly dissociable IgE-Fc epsilonRI aggregates downstream signaling pathways.

Aggregation of Fc epsilonRI, the high-affinity receptor for IgE, on RBL-2H3 mast cells caused by reversible ligands such as multivalent antigen causes cellular responses that can be halted by subsequent addition of excess monovalent ligand. In contrast, Ca2+ and degranulation responses elicited by effectively irreversible streptavidin cross-linking of biotinylated IgE-Fc epsilonRI are not stopped by addition of excess biotin after stimulation is initiated. These results support previous conclusions based on studies with covalent oligomers of IgE that stable cross-links can continue to deliver stimulatory signals for extended periods of time. Dissociation measured in the presence of monovalent hapten reveals two populations of IgE-Fc epsilonRI cross-linked by multivalent antigen that differ in functional effectiveness. Aggregates with readily dissociable cross-links are normally responsible for triggering essentially all of the degranulation response, whereas aggregates with poorly dissociable cross-links apparently do not trigger this response. Treatment of RBL-2H3 cells with cytochalasin D, an inhibitor of actin polymerization, enhances downstream signaling and enables the less readily dissociable aggregates to stimulate Ca2+ and degranulation responses. Under these conditions, cytochalasin D does not affect hapten-mediated dissociation of multivalent antigen, nor does it prevent hapten from reversing tyrosine phosphorylation of Syk. Cytochalasin D alone causes tyrosine phosphorylation of a protein at approximately 75 kDa, and it reduces hapten-induced reversal of antigen-stimulated tyrosine phosphorylation of several other proteins. Taken together, these results indicate that stimulated actin polymerization normally regulates the coupling of aggregated Fc epsilonRI to downstream signaling pathways, and they provide an explanation for seeming discrepancies between responses to stable and reversible cross-links.

Ca2+-dependent myosin II activation is required for uropod retraction during neutrophil migration.

Buffering of intracellular Ca2+ transients in human neutrophils leads to reduced motility due to defective uropod detachment on fibronectin and vitronectin-coated surfaces. Since one potential target of a rise in [Ca2+]i is the activation of myosin II, we characterized the role of myosin II during motility. Treatment of neutrophils with a myosin inhibitor (2,3-butanedione monoxime), or myosin light chain kinase inhibitors (ML-7, ML-9, or KT5926) resulted in impaired uropod retraction and a dose-dependent decrease in chemokinesis following stimulation with N-formyl-Met-Leu-Phe (fMLP). Treatment with ML-9 resulted in a redistribution of F-actin and talin to the non-retracted uropods, mimicking the redistribution observed during [Ca2+]i buffering. Impairment of uropod retraction and redistribution of F-actin and talin by myosin II inhibition was only observed on adhesive substrates such as fibronectin and not on poorly adhesive substrates such as human serum-coated glass. At higher concentrations of ML-9, cell polarization was inhibited and pseudopod extension occurred radially. Using an antibody specific for serine 19-phosphorylated regulatory light chain of myosin II, regions of activated myosin II were found at the leading edge as well as the uropod in motile fMLP-stimulated cells. [Ca2+]i depletion caused a 50% decrease in the level of serine 19-phosphorylated myosin II suggesting that activation of myosin II by intracellular Ca2+ transients may be an essential step in establishing a polarized pseudopod and providing the force required for uropod retraction during PMN motility on adhesive surfaces.

Oriented endocytic recycling of alpha5beta1 in motile neutrophils.

During cell migration, integrin attachments to the substratum provide the means to generate the traction and force necessary to achieve locomotion. Once the cell has moved over these attachments, however, it is equally important that integrins detach from the substratum. The fate of integrins after detachment may include release from the cell, lateral diffusion across the cell surface, or endocytosis and redelivery to the cell surface. Polymorphonuclear neutrophils (PMNs) become stuck on the extracellular matrix proteins fibronectin and vitronectin when their intracellular free calcium concentration ([Ca(++)]i) is buffered. Taking advantage of this feature of PMN migration, we investigated the fate of integrins to differentiate among various models of migration. We demonstrate that alpha5beta1, one of the fibronectin-binding integrins, is responsible for immobilization of [Ca(++)](i)-buffered PMNs on fibronectin. We find that alpha5 and beta1 are in endocytic vesicles in PMNs and that alpha5 colocalizes with a marker for an endocytic recycling compartment. When [Ca(++)](i) is buffered, alpha5 and beta1 become concentrated in clusters in the rear of the adherent cells, suggesting that [Ca(++)](i) transients are required for alpha5beta1 detachment from the substratum. Inhibition of alpha5beta1 detachment by buffering [Ca(++)](i) results in the depletion of alpha5 from both endocytic vesicles and the recycling compartment, providing compelling evidence that integrins are normally recycled by way of endocytosis and intracellular trafficking during cell migration. This model is further refined by our demonstration that the endocytic recycling compartment reorients to retain its localization just behind the leading lamella as PMNs migrate, indicating that membrane recycling during neutrophil migration has directionality. (Blood. 2000;95:2471-2480)

[Protein, immunological and "Gc", "Gm" and "Inv" picture in high-risk mastectomized subjects]. / Quadro proteico, immunologico e fattori "Gc" "Gm" ed "Inv" in soggetti mastectomizzati e ad alto rischio.

In the field of research on cancer we studied 294 women of which 142 who had undergone mastectomy, 70 selected for a high risk group, 82 normal. In order to determine some parameters who characterize the three groups we research for each the globulin factor Gc, Gm, and Inv, the proteic fractions and the immunoglobulins, as already pointed out by other investigators. The study of data points out results some times not according to previous reports. Comparing people who had undergone mastectomy and who had been selected for a high risk group, on the bases of GC phenotype together with immunoglobulins we obtained interesting values that characterize and delimit the two groups.