Spontaneous breathing promotes lung injury in an experimental model of alveolar collapse.

Vigorous spontaneous breathing has emerged as a promotor of lung damage in acute lung injury, an entity known as "patient self-inflicted lung injury". Mechanical ventilation may prevent this second injury by decreasing intrathoracic pressure swings and improving regional air distribution. Therefore, we aimed to determine the effects of spontaneous breathing during the early stage of acute respiratory failure on lung injury and determine whether early and late controlled mechanical ventilation may avoid or revert these harmful effects. A model of partial surfactant depletion and lung collapse was induced in eighteen intubated pigs of 32 ±4 kg. Then, animals were randomized to (1) SB-group: spontaneous breathing with very low levels of pressure support for the whole experiment (eight hours), (2) Early MV-group: controlled mechanical ventilation for eight hours, or (3) Late MV-group: first half of the experiment on spontaneous breathing (four hours) and the second half on controlled mechanical ventilation (four hours). Respiratory, hemodynamic, and electric impedance tomography data were collected. After the protocol, animals were euthanized, and lungs were extracted for histologic tissue analysis and cytokines quantification. SB-group presented larger esophageal pressure swings, progressive hypoxemia, lung injury, and more dorsal and inhomogeneous ventilation compared to the early MV-group. In the late MV-group switch to controlled mechanical ventilation improved the lung inhomogeneity and esophageal pressure swings but failed to prevent hypoxemia and lung injury. In a lung collapse model, spontaneous breathing is associated to large esophageal pressure swings and lung inhomogeneity, resulting in progressive hypoxemia and lung injury. Mechanical ventilation prevents these mechanisms of patient self-inflicted lung injury if applied early, before spontaneous breathing occurs, but not when applied late.

[THE SCALP AS A SPLIT-THICKNESS GRAFT DONOR IN THE TREATMENT OF A MASSIVE THERMAL INJURY]. / VLASISTE KAO DONOR TRANSPLANTATA DJELOMICNE DEBLJINE KOZE U LIJECENJU MASIVNE TERMALNE OZLJEDE.

We are presenting our initial experience with the utilization of the scalp as a donor for split thickness skin grafting in the treatment of massive thermal injuries. Rapid donor reepithelization, absence of hypertrophic scarring in the donor area, inconspicuous donor area and a large area for the procurement of grafts in the pediatric population are the advantages that are emphasized in the literature. The outcome in a 3-year-old boy who suffered a burn injury from an open fire in the family house on the 57% of his total body surface area (48% full thickness burn) showed that the "take rate", in the absence of a massive local infection, was around 80% and that the scalp can be utilized again as a donor area after a period of 14 days. Folliculitis and alopecia are complications that should be kept in mind when using this technique.

Duodenal Duplication Cyst: A Rare Differential Diagnosis in a Neonate with Bilious Vomiting.

Bilious vomiting is a relevant sign in neonates that requires immediate evaluation and diagnosis. A duplication of the intestinal tract is a possible cause of obstruction if located distally to the major duodenal papilla of Vater and most of them involve the jejunum, stomach, or colon. Duodenal duplications are very rare and can have an endoscopic or surgical treatment after diagnosis. We present a case of a 16-day-old term newborn that consulted because of bilious vomiting and after evaluation with imaging and upper endoscopy, a duodenal duplication cyst was found at the level of the third portion causing compression of the intestinal lumen that required surgical resolution with duodenocystostomy.

[Isolation of fetal liver oval cells in physiologic conditions form their natural niche]. / Aislamiento de células ovales de hígado fetal en condiciones fisiológicas a partir de su nicho natural.

The liver is characterized by a remarkable ability to proliferate and self-renew. In the situation of mild or moderate liver damage, hepatocytes carry out regeneration. Nevertheless, when liver damage is far too much extensive and the number of residual mature hepatocytes is not enough to accomplish regeneration, or likewise when mature hepatocyte proliferation is inhibited, hepatic regeneration depends on the activation of liver stem cells that give rise to oval cells. The population of liver stem cells is scant in normal liver. It is considered that in fetal liver this population is just over 1% of the cells. For this reason, it is necessary to isolate and enrich them for their study. With this goal several models of hepatic damage that permit the isolation of oval cells af ter the induction of massive hepatic injure have been developed. Here we present a simple methodology that allows the isolation of oval cells from rat fetal liver without prior induction of liver damage. The use of oval cell 2 (OC2) and oval cell 3 (OC3) antigens as molecular markers allowed the highly precise characterization of this cell population. Furthermore, the in vitro culture in presence of HGF yielded a substantial enrichment of the oval cell population.

Functional blockade of α5ß1 integrin induces scattering and genomic landscape remodeling of hepatic progenitor cells.

BACKGROUND: Cell scattering is a physiological process executed by stem and progenitor cells during embryonic liver development and postnatal organ regeneration. Here, we investigated the genomic events occurring during this process induced by functional blockade of α5ß1 integrin in liver progenitor cells. RESULTS: Cells treated with a specific antibody against α5ß1 integrin exhibited cell spreading and scattering, over-expression of liver stem/progenitor cell markers and activation of the ERK1/2 and p38 MAPKs signaling cascades, in a similar manner to the process triggered by HGF/SF1 stimulation. Gene expression profiling revealed marked transcriptional changes of genes involved in cell adhesion and migration, as well as genes encoding chromatin remodeling factors. These responses were accompanied by conspicuous spatial reorganization of centromeres, while integrin genes conserved their spatial positioning in the interphase nucleus. CONCLUSION: Collectively, our results demonstrate that α5ß1 integrin functional blockade induces cell migration of hepatic progenitor cells, and that this involves a dramatic remodeling of the nuclear landscape.