Evaluation of [Co(gly)3]- as a 35Cl- NMR Shift Reagent for Cellular Studies

We studied the efficacy of the tris-glycinatocobaltate(II) complex ([Co(gly)3]-) as a shift reagent (SR) for chloride by 35Cl NMR spectroscopy and compared to that of Co2+(aq). Due to the relatively low thermodynamic stability of [Co(gly)3]-, a 1:3 Co(II)/gly stoichiometric solution at physiological pH is approximately a 2:1 mixture of [Co(gly)2(H2O)2] and [Co(gly)(H2O)4]+. This SR was found to be stable up to higher pH values than Co2+(aq), better preventing Co(OH)2 formation at alkaline pH. No significant differences in the 35Cl- NMR chemical shift induced by Co(II)/gly or Co2+(aq) were observed in the presence of physiological concentrations of either Ca2+ or Mg2+, or of either Na+ or K+. Although Co2+(aq) was almost twice as effective as Co(II)/gly in shifting the 35Cl- NMR resonance at the same high ρ ([SR]/[Cl-]) value and low ionic strength, Co2+(aq) showed a significant decrease (p < 0.05) in the 35Cl- chemical shift at higher ionic strength. Line widths at half-height were significantly (p < 0.05) less for Co(II)/gly than for Co2+(aq) at ρ values in the range 0.066−0.40. Intracellular chloride was clearly detectable by 35Cl NMR spectroscopy in human skin fibroblast cells suspended in medium containing 40 mM Co(II)/gly SR. We determined that, although Co2+(aq) provides a larger shift than Co(II)/gly at the same ρ value, there are significant advantages for using Co(II)/gly, such as pH stability, ionic strength independent chemical shifts, narrow 35Cl- NMR resonances, and reduced cellular toxicity, as a SR in biological systems

The Why & How Our Trauma Patients Die: A Prospective Multicenter Western Trauma Association Study.

BackgroundHistorically, hemorrhage has been attributed as the leading cause (40%) of early death. However, a rigorous, real-time classification of the cause of death (COD) has not been performed. This study sought to prospectively adjudicate and classify COD to determine the epidemiology of trauma mortality.MethodsEighteen trauma centers prospectively enrolled all adult trauma patients at the time of death during December 2015 to August 2017. Immediately following death, attending providers adjudicated the primary and contributing secondary COD using standardized definitions. Data were confirmed by autopsies, if performed.ResultsOne thousand five hundred thirty-six patients were enrolled with a median age of 55 years (interquartile range, 32-75 years), 74.5% were male. Penetrating mechanism (n = 412) patients were younger (32 vs. 64, p &lt; 0.0001) and more likely to be male (86.7% vs. 69.9%, p &lt; 0.0001). Falls were the most common mechanism of injury (26.6%), with gunshot wounds second (24.3%). The most common overall primary COD was traumatic brain injury (TBI) (45%), followed by exsanguination (23%). Traumatic brain injury was nonsurvivable in 82.2% of cases. Blunt patients were more likely to have TBI (47.8% vs. 37.4%, p &lt; 0.0001) and penetrating patients exsanguination (51.7% vs. 12.5%, p &lt; 0.0001) as the primary COD. Exsanguination was the predominant prehospital (44.7%) and early COD (39.1%) with TBI as the most common later. Penetrating mechanism patients died earlier with 80.1% on day 0 (vs. 38.5%, p &lt; 0.0001). Most deaths were deemed disease-related (69.3%), rather than by limitation of further aggressive care (30.7%). Hemorrhage was a contributing cause to 38.8% of deaths that occurred due to withdrawal of care.ConclusionExsanguination remains the predominant early primary COD with TBI accounting for most deaths at later time points. Timing and primary COD vary significantly by mechanism. Contemporaneous adjudication of COD is essential to elucidate the true understanding of patient outcome, center performance, and future research.Level of evidenceEpidemiologic, level II

“The Why &amp; How Our Trauma Patients Die

BackgroundHistorically, hemorrhage has been attributed as the leading cause (40%) of early death. However, a rigorous, real-time classification of the cause of death (COD) has not been performed. This study sought to prospectively adjudicate and classify COD to determine the epidemiology of trauma mortality.MethodsEighteen trauma centers prospectively enrolled all adult trauma patients at the time of death during December 2015 to August 2017. Immediately following death, attending providers adjudicated the primary and contributing secondary COD using standardized definitions. Data were confirmed by autopsies, if performed.ResultsOne thousand five hundred thirty-six patients were enrolled with a median age of 55 years (interquartile range, 32-75 years), 74.5% were male. Penetrating mechanism (n = 412) patients were younger (32 vs. 64, p &lt; 0.0001) and more likely to be male (86.7% vs. 69.9%, p &lt; 0.0001). Falls were the most common mechanism of injury (26.6%), with gunshot wounds second (24.3%). The most common overall primary COD was traumatic brain injury (TBI) (45%), followed by exsanguination (23%). Traumatic brain injury was nonsurvivable in 82.2% of cases. Blunt patients were more likely to have TBI (47.8% vs. 37.4%, p &lt; 0.0001) and penetrating patients exsanguination (51.7% vs. 12.5%, p &lt; 0.0001) as the primary COD. Exsanguination was the predominant prehospital (44.7%) and early COD (39.1%) with TBI as the most common later. Penetrating mechanism patients died earlier with 80.1% on day 0 (vs. 38.5%, p &lt; 0.0001). Most deaths were deemed disease-related (69.3%), rather than by limitation of further aggressive care (30.7%). Hemorrhage was a contributing cause to 38.8% of deaths that occurred due to withdrawal of care.ConclusionExsanguination remains the predominant early primary COD with TBI accounting for most deaths at later time points. Timing and primary COD vary significantly by mechanism. Contemporaneous adjudication of COD is essential to elucidate the true understanding of patient outcome, center performance, and future research.Level of evidenceEpidemiologic, level II