RESUMEN
The intermolecular interaction and aggregation of the neutral complex fac-tris(2-phenylpyridinato-C(2),N)iridium(III) (fac-Ir(ppy)3) in solution was investigated. Intermolecular interactions were found to effectively decrease the luminescence lifetime via self-quenching with increasing fac-Ir(ppy)3 concentrations. A Stern-Volmer plot for quenching in acetonitrile was linear, due to bimolecular self-quenching, but curved in toluene as the result of excimer formation. (1)H NMR spectra demonstrated a monomer-aggregate equilibrium which resulted in spectral shifts depending on solvent polarity. X-ray crystallography provided structural information concerning the aggregate, which is based on a tetramer consisting of two Δ-fac-Ir(ppy)3-Λ-fac-Ir(ppy)3 pairs. Offset π-π stacking of ppy ligands and electrostatic dipole-dipole interactions between complex molecules play an important role in the formation of these molecular pairs.
Asunto(s)
Acetonitrilos/química , Benceno/química , Complejos de Coordinación/química , Compuestos Organometálicos/química , Cristalografía por Rayos X , Espectroscopía de Resonancia Magnética , Estructura Molecular , Solventes/químicaRESUMEN
An intramolecular reaction of 3-alkynyl and 3-alkenyl-2-arylpyridines selectively gave 4-azafluorene compounds in the presence of a catalytic amount of [Cp*RhCl(2)](2) and Cu(OAc)(2). Pyridine-directed C-H bond activation along with "rollover" are likely to be key steps of this transformation.
RESUMEN
Silahelicenes, which contain two silole moieties in a helically chiral structure, were synthesized by a chiral Ir-catalyzed intermolecular [2+2+2] cycloaddition of tetraynes with diynes along with a Ni-mediated intramolecular [2+2+2] cycloaddition. The photophysical properties of the obtained highly enantiomerically enriched silahelicenes (up to 93% ee) were also measured.
RESUMEN
We previously demonstrated that the deficiency of class A macrophage scavenger receptor type I/II was involved in the delayed phagocytosis of degraded myelin by macrophages in class A macrophage scavenger receptor type I/II knockout mice after crush injury of the sciatic nerve [Naba et al. (2000) Exp. Neurol., 166, 83-89]. In order to elucidate the role of CD36, one of the scavenger receptors, here we inflicted crush injury to the sciatic nerves of CD36 knockout mice and investigated the remyelination after crush injury in comparison with that of class A macrophage scavenger receptor type I/II knockout mice. Although we previously reported a lot of onion-bulbs in class A macrophage scavenger receptor type I/II knockout mice at 3 weeks, the number of onion-bulbs was limited both in CD36 knockout mice and wild-type mice. In the morphometry, the remyelination was seriously delayed, and the infiltrating macrophages into the nerve fascicles were quite frequent in CD36 knockout mice compared with wild-type mice at 3 and 6 weeks postinjury. The immunohistochemistry with the monoclonal antibody reacted with oxidized phosphatidylcholine and oil red O staining were positive in wild-type mice, but were negative in CD36 knockout mice, suggesting that the oxidation of phosphatidylcholine and the generation of neutral lipids in macrophages were disturbed in CD36 knockout mice. We hypothesize that the delayed phagocytosis by macrophages and the defect in reuse of lipids from degraded myelin are related to seriously delayed remyelination and a small number of onion-bulbs in CD36 knockout mice.
Asunto(s)
Antígenos CD36/metabolismo , Fibras Nerviosas Mielínicas/metabolismo , Neuropéptidos , Enfermedades del Sistema Nervioso Periférico/metabolismo , Nervio Ciático/metabolismo , Nervio Ciático/fisiopatología , Animales , Antígenos CD36/genética , Recuento de Células , Modelos Animales de Enfermedad , Femenino , Guanilato-Quinasas , Inmunohistoquímica/métodos , Lectinas/metabolismo , Macrófagos/metabolismo , Macrófagos/patología , Proteínas de la Membrana , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Vaina de Mielina/metabolismo , Vaina de Mielina/patología , Compresión Nerviosa/métodos , Fibras Nerviosas Mielínicas/patología , Proteínas Nucleares/metabolismo , Enfermedades del Sistema Nervioso Periférico/patología , Receptores Depuradores de Clase A , Nervio Ciático/lesiones , Nervio Ciático/patología , Coloración y Etiquetado/métodos , Factores de Tiempo , Factores de Transcripción/metabolismoRESUMEN
From October 2000 to September 2001, we collected the specimen from 410 patients with lower respiratory tract infections in 16 institutions in Japan, and investigated the susceptibilities of isolated bacteria to various anti-bacterial agents and antibiotics and patients' characteristics. Of 499 strains that were isolated from specimen (mainly from sputum) and assumed to be bacteria causing in inflammation, 493 strains were investigated. The breakdown of the isolated bacteria were: Staphylococcus aureus 78, Streptococcus pneumoniae 73, Haemophilus infiuenzae 99, Pseudomonas aeruginosa (non-mucoid) 64, P. aeruginosa (mucoid) 14, Klebsiella pneumoniae 25, Moraxella subgenus Branhamella catarrhalis 21, etc. Of 78 S. aureus strains, those with 4 micrograms/ml or more of MIC of oxacillin (methicillin-resistant S. aureus: MRSA) occupied 53.8%. Vancomycin and arbekacin had the most potent activities against MRSA as observed in 1999. The frequency of S. pneumoniae exhibiting low sensitivity to penicillin (penicillin-intermediate S. pneumoniae: PISP + penicillin-resistant S. pneumoniae: PRSP) was 38.4% being consistent with that in 1999 (34.7%). PRSP accounted for 11.0% of the total, being more than that in 1999 (3.0%). Carbapenems had strong activities against S. pneumoniae. Especially, panipenem inhibited the growth of all 73 strains at 0.125 microgram/ml. Generally, all drugs had strong activities against H. influenzae with MIC80s of 8 micrograms/ml or less. The drug that had the strongest activity against H. infiuenzae was levofloxacin, which inhibited the growth of 94 of the 99 strains at 0.063 microgram/ml. Tobramycin had a strong activity against P. aeruginosa (both mucoid and non-mucoid) with MIC80 of 1 microgram/ml. The mucoid strain was little isolated (14 strains) but the susceptibilities to all drugs were better than the non-mucoid strain. K. pneumoniae showed good susceptibilities to all drugs except ampicillin and the MIC80S were 2 micrograms/ml or less. Particularly, cefpirome, cefozopran, and levofloxacin had strong bactericidal activities against K. pneumoniae with MIC80s of 0.125 microgram/ml, and cefotiam, second-generation cephems, also had a favorable activity being MIC80 of 0.25 microgram/ml. Also, all drugs generally had strong activities against M. (B.) catarrhalis. MIC80s of all drugs were 2 micrograms/ml or less. The drug having the strongest activity was imipenem and levofloxacin inhibiting all 21 strains at 0.063 microgram/ml. Most of the patients with respiratory infection were aged 70 years or older, accounting for approximately a half of the total (44.4%). As for the incidence by the diseases, bacterial pneumonia and chronic bronchitis were the highest, being noted in 38.0% and 31.7% of all the patients, respectively. The bacteria frequently isolated from the patients with bacterial pneumonia were S. aureus (18.3%) and S. pneumoniae (16.1%). In contrast, H. infiuenzae (20.4%) and P. aeruginosa (both mucoid and non-mucoid: 16.7%) were frequently isolated from the patients with chronic bronchitis. Before the drug administration, the bacteria frequently isolated from all the patients were S. pneumoniae (24.3%) and H. infiuenzae (26.7%). The frequency of isolated S. pneumoniae tended to decrease with the increase in the number of administration days while that of isolated H. infiuenzae did not. The frequency of isolated P. aeruginosa tended to increase with the duration of administration. The isolated bacteria were comparable between the patients already treated with penicillins and cephems. In the patients treated with aminoglycosides, macrolides, and quinolones, P. aeruginosa was most frequently isolated (33.3 to 40.0%).