Syntheses, Characterization, Density Functional Theory Calculations, and Activity of Tridentate SNS Zinc Pincer Complexes Based on Bis-Imidazole or Bis-Triazole Precursors

A series of tridentate pincer ligands, each possessing two sulfur- and one nitrogen-donor functionalities (SNS), based on bis-imidazole or bis-triazole salts were metallated with ZnCl2 to give new tridentate SNS pincer zinc(II) complexes [(SNS)ZnCl]+. The zinc complexes serve as models for the zinc active site in liver alcohol dehydrogenase (LADH) and were characterized with single crystal X-ray diffraction, 1H, 13C, and HSQC NMR spectroscopies, electrospray mass spectrometry, and elemental analysis. The zinc complexes feature SNS donor atoms and pseudotetrahedral geometry about the zinc center, as is seen for liver alcohol dehydrogenase. The bond lengths and bond angles of the zinc complexes correlate well to those in horse LADH. The SNS ligand precursors were characterized with 1H, 13C, and HSQC NMR spectroscopies, elemental analysis, and cyclic voltammetry, and were found to be redox active. Gaussian calculations were performed and agree with the experimentally observed oxidation potentials for the pincer ligand precursors. The zinc complexes were screened for the reduction of electron-poor aldehydes in the presence of a hydrogen donor, 1-benzyl-1,4-dihydronicotinamide (BNAH), and it was determined that they enhance the reduction of electron-poor aldehydes. The SNS zinc pincer complexes with bis-triazole ligand precursors exhibit higher activity for the reduction of 4-nitrobenzaldehyde than do SNS zinc pincer complexes with bis-imidazole ligand precursors. Quantitative stoichiometric conversion was seen for the reduction of pyridine-2-carboxaldehyde via SNS zinc pincer complexes with either bis-imidazole or bis-triazole ligand precursors

Can the Non-pneumatic Anti-Shock Garment (NASG) reduce adverse maternal outcomes from postpartum hemorrhage? Evidence from Egypt and Nigeria

<p>Abstract</p> <p>Background</p> <p>Postpartum hemorrhage (PPH) is the leading cause of maternal mortality and severe maternal morbidity. The Non-pneumatic Anti-Shock Garment (NASG), a first-aid lower-body compression device, may decrease adverse outcomes from obstetric hemorrhage. This article is the first to report the effect of the NASG for PPH.</p> <p>Methods</p> <p>This pre-intervention/NASG study of 854 women was conducted in four referral facilities in Nigeria and two in Egypt between 2004-2008. Entry criteria were women with PPH due to uterine atony, retained placenta, ruptured uterus, vaginal or cervical lacerations or placenta accreta with estimated blood loss of ≥ 750 mL and one clinical sign of shock. Differences in demographics, conditions on study entry, treatment and outcomes were examined. The Wilcoxon rank-sum test and relative risks with 95% confidence intervals were calculated for primary outcomes - measured blood loss, emergency hysterectomy, mortality, morbidity (each individually), and a combined variable, "adverse outcomes", defined as severe morbidity and mortality. A multiple logistic regression model was fitted to test the independent association between the NASG and the combined severe morbidity and mortality outcome.</p> <p>Results</p> <p>Measured blood loss decreased by 50% between phases; women experienced 400 mL of median blood loss after study entry in the pre-intervention and 200 mL in the NASG phase (p < 0.0001). As individual outcomes, mortality decreased from 9% pre-intervention to 3.1% in the NASG phase (RR 0.35, 95% CI 0.19-0.62); severe morbidity decreased from 4.2% to 1%, in the NASG phase (RR 0.24, 95% CI 0.09-0.67). As a combination, "adverse outcomes," decreased from 12.8% to 4.1% in the NASG phase (RR 0.32, 95% CI 0.19-0.53). In a multiple logistic regression model, the NASG was associated with the combined outcome of severe maternal morbidity and mortality (OR 0.42, 95% CI 0.18-0.99).</p> <p>Conclusion</p> <p>In this non-randomized study, in which bias is inherent, the NASG showed promise for reducing blood loss, emergency hysterectomy, morbidity and mortality associated with PPH in referral facilities in Egypt and Nigeria.</p

Combined analysis of the non-pneumatic anti-shock garment on mortality from hypovolemic shock secondary to obstetric hemorrhage

Abstract Background Obstetric hemorrhage is the leading cause of maternal mortality, particularly in low-resource settings where women face significant delays in accessing definitive treatment. The Non-pneumatic Anti-Shock Garment (NASG) is a first-aid device to stabilize women in hypovolemic shock secondary to obstetric hemorrhage. Prior studies on the effectiveness of the NASG have suffered from small sample sizes and insufficient statistical power. We sought to generate a summary effect estimate of this intervention by combining data from all previous quasi-experimental studies. Methods Five quasi-experimental studies that tested the NASG as treatment for hypovolemic shock secondary to obstetric hemorrhage at the tertiary care facility level were included in the analysis. We evaluated heterogeneity of effect across studies and calculated pooled odds ratios. We also conducted a subgroup analysis among women in the most severe condition. Results Participant characteristics were similar across studies with some variation in hemorrhage etiology. Median blood loss was at least 50% lower in the intervention group than the control group. The pooled odds ratio suggested that NASG intervention was associated with a 38% significantly reduced odds of mortality among the overall sample, and a 59% significantly reduced odds of mortality among the most severe women. Conclusions The results from this combined analysis suggest that NASG intervention is associated with a reduced odds of death for women with hypovolemic shock secondary to obstetric hemorrhage. Further research should focus on application of the NASG at the community or primary health care level, and utilize a more robust methodology