Changes in uncuffed endotracheal tube leak during laparoscopic inguinal herniorrhaphy in children.

The present study was conducted to investigate changes in uncuffed endotracheal tube (ETT) leak during laparoscopic surgery. The study included 31 patients aged between 1 and 6 years scheduled for elective laparoscopic inguinal herniorrhaphy. Inspiratory and expiratory tidal volumes (TVi and TVe) were measured during mechanical ventilation, and ETT leak was calculated using the formula-ETT leak = (TVi - TVe)/TVi × 100 (%), assessed at the following time-points-5 min after the start of mechanical ventilation (T1, baseline), just before the start of surgery (T2), 5 min after the induction of pneumoperitoneum with 15° Trendelenburg tilt (T3), and at the end of surgery (T4). Additionally, leak pressure was assessed after successful tracheal intubation (T0, baseline) at T2, T3 and T4. Uncuffed ETT leak significantly decreased at T3 compared with T1 (baseline). Leak pressure significantly increased at T3 and T4 compared with T0 (baseline). Further studies are needed in order to determine whether the results are universal and associated with clinically significant outcomes.

Obligatory Role of Early Ca(2+) Responses in H2O2-Induced ß-Cell Apoptosis.

Our previous study using apoptosis analysis suggested that Ca(2+) release through inositol 1,4,5-trisphosphate (IP3) receptors and the subsequent Ca(2+) influx through store-operated channels (SOCs) constitute a triggering signal for H2O2-induced ß-cell apoptosis. In the present study, we further examined the obligatory role of early Ca(2+) responses in ß-cell apoptosis induction. H2O2 induced elevation of the cytosolic Ca(2+) concentration ([Ca(2+)]c) consisting of two phases: an initial transient [Ca(2+)]c elevation within 30 min and a slowly developing one thereafter. The first phase was almost abolished by 2-aminoethoxydiphenylborate (2-APB), which blocks IP3 receptors and cation channels including SOCs, while the second phase was only partially inhibited by 2-APB. The inhibition by 2-APB of the second phase was not observed when 2-APB was added 30 min after the treatment with H2O2. 2-APB also largely inhibited elevation of the mitochondrial Ca(2+) concentration ([Ca(2+)]m) induced by H2O2 when 2-APB was applied simultaneously with H2O2, but not when applied 30 min after H2O2 application. In addition, 2-APB inhibited the release of mitochondrial cytochrome c to the cytosol induced by H2O2 when 2-APB was applied simultaneously with H2O2 but not 30 min post-treatment. H2O2-induced [Ca(2+)]m elevation and cell death were not inhibited by Ru360, an inhibitor of the mitochondrial calcium uniporter (MCU). These results suggest that the H2O2-induced initial [Ca(2+)]c elevation, occurring within 30 min and mediated by Ca(2+) release through IP3 receptors and subsequent Ca(2+) influx through SOCs, leads to [Ca(2+)]m elevation, possibly through a mechanism independent of MCU, thereby inducing cytochrome c release and consequent apoptosis.

Inositol 1,4,5-trisphosphate receptor-mediated initial Ca(2+) mobilization constitutes a triggering signal for hydrogen peroxide-induced apoptosis in INS-1 ß-cells.

Reactive oxygen species, including hydrogen peroxide (H(2)O(2)), are known to induce ß-cell apoptosis. The present study investigated the role of Ca(2+) in H(2)O(2)-induced apoptosis of the ß-cell line INS-1. Annexin V assay with flow cytometry and DNA ladder assay demonstrated that treatment of INS-1 cells with 100 µM H(2)O(2) for 18 h significantly increased apoptotic cells. A comparable level of apoptosis was also observed after 18 h when the cells were treated with 100 µM H(2)O(2) only for initial 30 min. The H(2)O(2)-induced apoptosis was abolished by 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetra(acetoxymethyl)ester (BAPTA/AM), a chelator of intracellular Ca(2+), by 2-aminoethoxydiphenylborate (2-APB), a blocker of inositol 1,4,5-trisphosphate (IP(3)) receptors and cation channels, and by xestospongin D, a blocker of IP(3) receptors, and was partially blocked by SKF-96365, a non-selective cation channel blocker. However, nicardipine, an L-type voltage-dependent Ca(2+) channel blocker, or N-(p-amylcinnamoyl)anthranilic acid (ACA), a TRPM2 blocker, had little effect on the apoptosis. The inhibitory effect of BAPTA/AM or 2-APB on the H(2)O(2)-induced apoptosis was largely attenuated when the drug was added 30 min or 1 h after start of the treatment with H(2)O(2). These results suggest that the initial intracellular Ca(2+) elevation induced by H(2)O(2), which is mediated via IP(3) receptors and store-operated cation channels, plays an obligatory role in the induction of ß-cell apoptosis.

cGMP-independent anti-apoptotic effect of nitric oxide on thapsigargin-induced apoptosis in the pancreatic beta-cell line INS-1.

AIMS: Low concentrations of nitric oxide (NO) produced by constitutive NO synthase (cNOS) in pancreatic beta-cells have been suggested to be a physiological regulator of insulin secretion. In contrast, excessive NO produced by inducible NO synthase is known to mediate beta-cell apoptosis. The aim of the present study was to investigate the effect of low concentrations of NO on beta-cell apoptosis. MAIN METHODS: Apoptosis of the pancreatic beta-cell line INS-1 was quantitatively determined by Annexin V flow cytometry. KEY FINDINGS: The 24-h incubation with 1 mM DETA/NO, a long half-life NO donor, induced beta-cell apoptosis, which was insensitive to the soluble guanylate cyclase (sGC) inhibitor ODQ. In contrast, DETA/NO at lower concentrations until 300 microM concentration-dependently decreased the apoptosis induced by thapsigargin, an inhibitor of endoplasmic reticulum Ca2+-ATPase. ODQ did not affect the anti-apoptotic effect of DETA/NO. Moreover, neither the cGMP analogue 8-Br-cGMP nor the sGC activator YC-1 mimicked the anti-apoptotic effect of DETA/NO. SIGNIFICANCE: These results suggest that low levels of NO protect beta-cells from thapsigargin-induced apoptosis in a cGMP-independent manner.