Radiation effects on oxidative metabolism in young and aged rat alveolar macrophages.

The effect of ionizing radiation on metabolic functions of alveolar macrophages (AM) have been well studied. However, variations associated to age have not been established yet. The aim of this work was to perform a comparative study on irradiated alveolar macrophages from young and aged rat lungs. Cell viability and occurrence of apoptosis as well as production of nitric oxide (NO), generation of superoxide anion (O2*-) and total antioxidant capacity were analyzed in vitro after exposure to gamma-irradiation with 10, 25, 50 and 75 Gy. Cell viability decreased only in the aged population at the higher doses. Morphological features of apoptosis were clearly evidenced in irradiated alveolar macrophages from aged animals although the DNA fragmentation assay for apoptosis showed no differences for either of the populations studied. NO production and total reactive antioxidant potential (TRAP) levels showed a dose-dependent modulation. Low radiation doses inhibited the production of NO and decreased TRAP levels whereas higher doses enhanced the NO production and increased the TRAP levels in both macrophage populations. Generation of O2*- was always higher in the aged population for all the doses assayed. We conclude that in vitro young alveolar macrophages exhibited higher radioresistance over the whole range of doses as compared to the aged macrophage population. Our results show that the aging process markedly affects the radioresistance of phagocytic cells. Therefore, immune defense and inflammatory response of lungs from aged patients should be considered when planning radiotherapy protocols.     

Insertion reactions of 1,4-diisocyanobenzene in binuclear Pd(I) complexes

Reactions between XPd(μ-dmp)₂PdX′ (X = X′ = Cl, Br, I, NCO, SCN, N₃ or C₆F₅; X = C₆F₅, X′ = Cl, Br, I, NCO) with 1,4-diisocyanobenzene lead to the tetranuclear complexes [(μ,μ′-CNC₆H₄NC){XPd(μ-dpm)₂PdX′}₂], where both ends of the diisocyanide are inserted in a metalmetal bond. The cationic derivatives [(μ,μ′-CNC₆H₄NC){(RNC)Pd(μ-dpm)₂(CNR)}₂](BPh₄)₄ and [(μ,μ′-CNC₆H₄NC){(RNC)Pd(μ-dpm)₂Pd(C₆F₅)}₂] (BPh₄)₂ (R = p-Tol, Cy, or ^tBu) are obtained by reacting [(μ,μ′-CNC₆H₄NC){ClPd(μ-dpm)₂PdX}₂] (X= Cl or C₆F₅) with RNC in the presence of NaBPh₄. Treatment of [(μ,μ′-CNC₆H₄NC){ClPd(μ-dpm)₂Pd(C₆F₅)}]₂ with NaBPh₄ causes the di-insertion and subsequent coordination of the isocyanide, yielding [(C₆F₅)Pd(CN-C₆H₄NC) Pd(μ-dpm)₂Pd(C₆F₅)](BPh₄)₂.     

Alkaloids of Lycopodium paniculatum: The structure of paniculine

Three new alkaloids isolated from Lycopodium paniculatum were identified as paniculine (7α-hydroxy-acetyldihydrolycopodine), deacetylpaniculine and anhydrodeacetylpaniculine. Other known alkaloids isolated include flabellidine, lycoclavine, together with deacetyllycoclavine previously obtained as a degradation product of lycoclavine.     

Alkaloids of Lycopodium magellanicum

Six alkaloids have been isolated from Lycopodium magellanicum. These include the known alkaloids lycopodine, acetyldihydrolycopodine, lycodine, N-methyllycodine, acetylfawcettine and a new alkaloid, 5-dehydro-magellanine. The chemical correlation of magellanine and paniculatine and the establishment of their absolute configuration are described.     

Environmental effects on the fluorescence behaviour of carbazole derivatization reagents.

The carbazole ring is the basic structure present in the fluorescence derivatization reagents 9-chlorocarbonylcarbazole and 9-carbazolylacetic acid. The fluorescence behaviour of these carbazole derivatives was studied in solvents with different polarities (cyclohexane, ethanol, acetonitrile, water) and at different pH values (4.5 and 8.8). The influence of the low polarity environment afforded by 2-hydroxypropyl-beta-cyclodextrin (HPbeta-CD) is also described. The behaviour of the fluorescent reagents is compared to the model molecules carbazole and 9-methylcarbazole. For all derivatives studied, a bathochromic shift in the fluorescence emission maxima was observed when the solvent polarity was increased. A bathochromic shift was observed in dioxane solutions, which can be ascribed to the peculiar behaviour of this solvent. The changes in the fluorescence intensity in the case of 9-carbazolylacetic acid can be related to the ionization of the carboxylic acid group. Inclusion into the cavity of HPbeta-CD allows emission spectra to be obtained close to those obtained in ethanolic solutions with a remarkable enhancement in the fluorescence intensity, depending on the chemical structure of the carbazole derivative included.     

Fluorescence quenching of beta-carboline alkaloids in micellar media. A study to select the adequate surfactant to use in analytical techniques.

The study of fluorescence quenching of the fluorophores allows the localization of the alkaloids (harmane and harmine) in the micelles (SDS, CTAB, Brij-35) to be established. In aqueous micellar solutions (SDS and Brij-35) at pH 13.0, emission corresponding to the neutral or zwitterionic forms can be observed. In the presence of CTAB (pH = 13.0) it was possible to observe the emission of anionic form. These species are not present in buffered aqueous solutions at these pH values. Bromide ion was added to the different surfactant solutions and the quenching effect was studied according to the Stern-Volmer equation. In the presence of SDS the quenching effect is considerably reduced compared to the aqueous solutions without surfactants, while for Brij-35 micelles were similar to those observed in homogeneous aqueous solution. For CTAB micelles a notable fluorescence quenching was observed for the different pH values studied. The fluorescence quenching studies show that the neutral species are associated inside the micelles, instead of the ionic species (cationic, zwitterionic or anionic) remaining on the surface of the micelles. The anionic surface of SDS micelles prevents the quenching effect by anionic quenchers for both neutral and charged species.     

The Combined Perls-Hematoxylin-Eosin Stain

To provide a routine check for the presence of ferric iron in sections, Perls' method was combined with hematoxylin and eosin as follows. Deparaffinized sections of formalin-fixed tissues are stained in Perls' reagent (1:1 2%, w/v, of potassium ferrocyanide in distilled water and 2%, v/v, concentrated HCl in distilled water) for 20 min. After brief rinsing in distilled water stain sections in Mayer's hemalum, wash in tap water for 5 min, counterstain in 0.5% (w/v) eosin B in 50% ethyl alcohol for 15 sec. Rinse in tap water, dehydrate and mount as usual.