RESUMO
The synthesis, acid-base behavior and Pb2+ coordination chemistry of the new aza-scorpiand like ligand 5-[2-(N-2-fluorenyl)ethylamino]-2,5,8-triaza[9]-2,6-pyridinophane (L1) have been studied by potentiometry, NMR and spectrofluorimetric titrations, and the results are compared with those obtained for the related compounds L2, lacking the fluorenyl group, and L3, the macrocycle lacking the pendant arm. The crystal structures obtained for complexes [PbL1][PbL1Cl](NO3)Cl2·4H2O (1) and [PbL3](ClO4)2 (2) reveal that the metal ion is located over the plane defined by the nitrogen atoms of the macrocyclic core due to its inability to accommodate the large Pb2+ ion in the macrocyclic cavity. For L1, the secondary amino group of the pendant arm is implicated in the coordination of the metal ion, although the stereoactive lone pair of Pb2+ prevents the closed conformation associated with the coordination of metal ions in aza-scorpiand derivatives. The kinetics of the acid-promoted dissociation of the ligand from the Pb2+ complexes with the three ligands have been studied using stopped-flow with simultaneous absorbance and fluorescence detection. The results indicate that in spite of their similarity, the dissociation of the metal ion occurs with very different rates in the three complexes. During the course of the kinetic studies evidence was obtained for the occurrence of a photochemical process that leads to ligand degradation with the unexpected elimination of one CH2CH2 fragment from the macrocyclic core.
RESUMO
Primary percutaneous coronary intervention (PCI) is the preferred reperfusion method in patients with ST-elevation myocardial infarction (STEMI) if it can be performed in a timely manner in high-volume centers. Regional STEMI networks improve timely access to PCI but are frequently criticized for being single center. To determine if results of regional STEMI systems could be replicated and achieve similar outcomes in 2 separate geographic regions, we examined the prospective databases of 2 large regional STEMI networks that use identical standardized protocols and integrated transfer systems. The Minneapolis Heart Institute (MHI) database included 2,266 patients with STEMI from 31 hospitals (498 at the PCI hospital, 1,033 transferred from 11 hospitals <60 miles away, and 735 transferred from 19 hospitals 60 to 210 miles away). The Iowa Heart Center (IHC) database included 1,206 patients with STEMI from 24 hospitals (710 at the PCI hospital, 266 transferred from 10 hospitals <60 miles away, and 230 transferred from 13 hospitals 60 to 120 miles away). Median total door-to-balloon times for the PCI hospital, zone 1, and zone 2 patients were 64, 95, and 123 minutes for the MHI and 59, 102, and 136 for the IHC (p <0.05 for each comparison between MHI and IHC). Overall in-hospital, 30-day, and 1-year mortalities was 4.8%, 5.4%, and 8.0% respectively (p = NS for each comparison between MHI and IHC). In conclusion, the use of identical protocols in 2 large regional STEMI systems in geographically separate locations produced nearly identical outcomes, adding to evidence that regional STEMI centers expand timely access to PCI.
