Impact of a physician-staffed helicopter on a regional trauma system: a prospective, controlled, observational study.

INTRODUCTION: This study aims to compare the trauma system before and after implementing a physician-staffed helicopter emergency medical service (PS-HEMS). Our hypothesis was that PS-HEMS would reduce time from injury to definitive care for severely injured patients. METHODS: This was a prospective, controlled, observational study, involving seven local hospitals and one level I trauma centre using a before and after design. All patients treated by a trauma team within a 5-month period (1 December 2009-30 April 2010) prior to and a 12-month period (1 May 2010-30 April 2011) after implementing a PS-HEMS were included. We compared time from dispatch of the first ground ambulance to arrival in the trauma centre for patients with Injury Severity Score (ISS) > 15. Secondary end points were the proportion of secondary transfers and 30-day mortality. RESULTS: We included 1788 patients, of which 204 had an ISS > 15. The PS-HEMS transported 44 severely injured directly to the trauma centre resulting in a reduction of secondary transfers from 50% before to 34% after implementation (P = 0.04). Median delay for definitive care for severely injured patients was 218 min before and 90 min after implementation (P < 0.01). The 30-day mortality was reduced from 29% (16/56) before to 14% (21/147) after PS-HEMS (P = 0.02). Logistic regression showed PS-HEMS had an odds ratio (OR) for survival of 6.9 compared with ground transport. CONCLUSIONS: Implementation of a PS-HEMS was associated with significant reduction in time to the trauma centre for severely injured patients. We also observed significantly reduced proportions of secondary transfers and 30-day mortality.

Design, synthesis, and bioactivity of the first nonsteroidal mimetics of brassinolide.

Ten novel compounds, each consisting of two subunits and a linker, were designed with the aid of molecular modeling to resemble the natural steroidal phytohormone brassinolide. The mimetics were synthesized and subjected to the rice leaf lamina inclination bioassay to test for brassinosteroid activity. Most of the mimetics displayed very weak or no bioactivity, but two were strongly active when coapplied with the auxin indole-3-acetic acid (IAA), which synergizes the activity of brassinosteroids. Thus, 1-(4,6 alpha,7 alpha-trihydroxy-5,6,7,8-tetrahydronaphthyl)-2-(6 alpha',7 alpha'-dihydroxy-5',6',7',8'-tetrahydronaphthyl)ethyne (4) and (E)-1,2-bis[trans-(4a alpha,8a beta)-4-oxo-6 alpha,7 alpha-dihydroxy-4a,5,6,7,8,8a-hexahydro-(3H)-naphthyl]ethylene (11) showed exceptional activity at doses as low as 0.01 ng and 0.001 ng/plant, respectively. These compounds are the first biologically active nonsteroidal brassinolide mimetics.

Regional development of glutamate-N-methyl-D-aspartate receptor sites in asphyxiated newborn infants.

The N-methyl-D-aspartate (NMDA) subclass of glutamate receptors was examined in newborn infants dying between 25 weeks' gestation and term, either from acute cerebral hypoxia, or from other noncerebral conditions incompatible with life. Frontal, occipital, temporal, and motor cortex tissue samples were obtained at autopsy (post mortem delay: median, 45.9 hr; range, 24-96 hr) and frozen for subsequent [3H]MK801 homogenate binding assays. Whereas no significant variation was observed in ligand affinity (KD), in all cases receptor density (BMAX) increased with gestational age, in occipital cortex (27 weeks, BMAX = 222 +/- 44 fmol x mg protein(-1); 39 weeks, 439 +/- 42 fmol x mg protein[-1]), but not in motor or temporal cortex. The gestational-age increase also occurred in control frontal cortex (27 weeks, 284 +/- 80; 39 weeks, 567 +/- 40 fmol x mg protein[-1]), but was significantly less marked in frontal cortex in hypoxia cases (27 weeks, 226 +/- 90; 39 weeks, 326 +/- 47 fmol x mg protein[-1]). In all cortical areas except temporal, the maximal response to glutamate did not vary across case groups. Hypoxia cases showed an increased response to glutamate enhancement selectively in temporal cortex. Binding site density did not correlate with degree of hypoxia as assessed pathologically, suggesting that receptor differences preceded the hypoxic episode. Regional differences in glutamate-NMDA receptor sites may underlie increased vulnerability to hypoxia at birth.

Developmental rearrangements of cortical glutamate-NMDA receptor binding sites in late human gestation.

NMDA-preferring glutamate receptor biding sites were characterized using the site-selective ligand [3H]MK801, in synaptic membranes prepared from cerebral cortex tissue obtained postmortem from human infants who had died with minimal neurological and neuropathological impairment between 22 and 42 weeks' gestation. It proved necessary to modify the assay protocol used with adult tissue before reliable data could be obtained. In the four cortical region studied (prefrontal, motor, occipital, temporal), [3H]MK801 bound to a single class of sites which showed significant variations in affinity only in motor cortex. The density of [3H]MK801 binding sites (calculated at constant affinity) showed marked increases in all cortical regions over this period. The extent to which glutamate could enhance [3H]MK801 binding became significantly lower in prefrontal and motor cortex as gestation progressed, so that at term, little activation was apparent. In occipital and temporal cortex, this parameter was low throughout late gestation. The evidence suggests that Glutamate-NMDA binding sites may undergo structural rearrangements which alter their ability to interact with ligands during the later stages of human gestation, and that such changes are regionally variable.