Correlation between end-tidal carbon dioxide and partial pressure of arterial carbon dioxide in ventilated newborns / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To study the correlation between end-tidal carbon dioxide (PetCO2) and partial pressure of arterial carbon dioxide (PaCO2) in ventilated newborns.</p><p><b>METHODS</b>Thirty-one ventilated newborn underwent mainstream PetCO2 monitoring; meanwhile, arterial blood gas analysis was performed. The correlation and consistency between PetCO2 and PaCO2 were assessed.</p><p><b>RESULTS</b>A total of 85 end-tidal and arterial CO2 pairs were obtained from 31 ventilated newborns. The mean PetCO2 (41±10 mm Hg) was significantly lower than the corresponding mean PaCO2 (46±11 mm Hg) (P<0.01). There was a significant positive correlation between PetCO2 and PaCO2 (r=0.92, P<0.01). The overall PetCO2 bias was 5.1±4.3 mm Hg (95% limits of consistency, -3.3 to 13.6 mmHg), and 5% (4/85) of the points were beyond the 95%CI. When the oxygenation index (OI) was less than 300 mm Hg (n=48), there was a significant positive correlation between PetCO2 and PaCO2 (r=0.85, P<0.01); the PetCO2 bias was 5.9±4.3 mm Hg (95% limits of consistency, -2.6 to 14.5 mm Hg), and 4.2% (2/48) of the points were beyond the 95%CI. When the OI was more than 300 mm Hg (n=37), there was also a significant positive correlation between PetCO2 and PaCO2 (r=0.91, P<0.01); the PetCO2 bias was 4.1±4.1 mm Hg (95% limits of consistency, -3.9 to 12.1 mm Hg), and 5% (2/37) of the points were beyond the 95%CI.</p><p><b>CONCLUSIONS</b>There is a good correlation and consistency between PetCO2 and PaCO2 in ventilated newborns.</p>

The construction and identification of siRNA expression vector against hypoxia inducible factor -1 alpha in vitro / 中国当代儿科杂志

<p><b>OBJECTIVE</b>Previous studies have suggested that under hypoxic conditions hypoxia inducible factor-1 alpha (HIF-1 alpha) contributes to the progression of neonatal pulmonary hemorrhage (NPH) by increasing the expression of endothelin-1 (ET-1) gene. RNA interference (RNAi) refers to the process of sequence-specific post-transcriptional gene-silencing mediated by double-stranded RNA. This new gene-silencing technique has recently been shown to be a powerful approach for studying gene function. The aim of this study was to construct the small interfering RNA (siRNA) eukaryotic expression vectors specific to human HIF-1 alpha gene (pSIREN-Shuttle HIF-1 alpha siRNAin order to observe its silencing effect on HIF-1 alpha under hypoxic conditions.</p><p><b>METHODS</b>Six potential siRNA target sites (a-fspecific to human HIF-1 alpha gene were designed and synthesized to two complementary oligonucleotides (A-F) for each siRNA target site. Using a gene recombination technique, the recombinant expression vectors (A-F') were constructed by cloning the double strands oligonucleotide into RNAi-Ready pSIREN vector. The recombinant vectors were then transfected into the cultured human umbilical vein endothelial cells (HUVECs). After 48 hrs of culture, the cells were treated with CoCl2 (100 mu M) for 3 hrs. Expression of HIF-1 alpha mRNA and protein was detected using RT-PCR and Western blot. ET-1 level in cell culture supernates was detected using ELISA.</p><p><b>RESULTS</b>The recombinant HIF-1 alpha siRNA eukaryotic expression vectors A'-F'respectively aiming at sites (a-f) were constructed successfully. Compared to the non-transfection group, liposome-mediated gene transfection of pSIREN-Shuttle HIF-1 alpha siRNA expression vectors into HUVECs obviously down-regulated the mRNA and protein levels of HIF-1 alpha, and partly decreased the ET-1 level in the B' and D' transfection groups.</p><p><b>CONCLUSIONS</b>The specific pSIREN-Shuttle HIF-1 alpha siRNA expression vectors B' and D' aiming at b and d sites can inhibit the expression of HIF-1 alpha, thus decreasing the level of its target gene ET-1. This may be helpful to study the relationship between HIF-1 alpha and neonatal pulmonary hemorrhage in vivo in future.</p>

Effect of NADPH oxidase on hypoxia-inducible factor-1alpha and endothelin-1 expression in human umbilical endothelial cells and its possible mechanism / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To study the effect of NADPH oxidase on hypoxia-inducible factor (HIF)-1alpha and endothelin (ET)-1 expression in human umbilical endothelia cells (HUVECs) and its possible mechanism.</p><p><b>METHODS</b>Twenty-five bottles of HUVECs culture fluid were randomly assigned into five groups: group A (normoxic control), group B (hypoxic), group C (NADPH oxidase inhibitor apocynin + normoxic), group D (H2O2 which can degrade HIF-1alpha rapidly+hypoxic) and group E (H2O2+apocynin+normoxic), with five bottles in each group. The culture supernates were collected and the total protein was extracted 3 hrs after treatment. Western Blot and ELISA were used to detect the HIF-1alpha protein expression in HUVECs and the ET-1 level in the culture supernates respectively.</p><p><b>RESULTS</b>There was a lower expression of HIF-1alpha protein (0.336 +/- 0.012) and lower ET-1 levels (5.87 +/- 2.22 pg/mL) in group A. The HIF-1alpha protein expression in groups B and C (0.773 +/- 0.018 and 0.888 +/- 0.022) and ET-1 levels (95.38 +/- 8.06 and 33.67 +/- 4.21 pg/mL) were noticeably higher than in group A (P < 0.05). The groups D and E had the HIF-1alpha protein expression levels similar to group A, but the ET-1 levels in group D (108.43 +/- 8.38 pg/mL) and group E (109.66 +/- 5.80 pg/mL) were significantly higher than in group A (P < 0.05).</p><p><b>CONCLUSIONS</b>Hypoxia or apocynin can increase the HIF-1alpha and ET-1 expression in HUVECs. H2O2 can inhibit the HIF-1alpha expression but increase the ET-1levels. It is speculated that NADPH oxidase as an oxygen sensor regulates the HIF-1alpha expression by changing the intracellular redox reaction and that except HIF-1, H2O2 might contribute to ET-1 synthesis and release.</p>