ALBERT

Notes: Abstract Recent studies suggest that granulocytes (PMNs) play a role in the pathogenesis of acute and chronic myocardial ischemia and extension of myocardial injury. Granulocytes can release a variety of molecules mediating tissue injury which act synergistically with other molecules and cells. The aim of our investigation was to evaluate the granulocyte function in patients affected by coronary artery disease (CAD) and during coronary angioplasty (PTCA). We studied 20 patients suffering from CAD. The PMN's aggregating activity was greater in the coronary sinus than in the aorta (P〈0.01). The increase in aggregating activity was evident in patients who were smokers: their cells release significantly lower quantities of leukotriene C4 (P〈0.025). In the 20 patients who underwent coronary angioplasty we analyzed superoxide release after stimulation with phorbolmyristate-acetate (PMA). The results showed a greater decrease of PMN's superoxide production in the coronary sinus than in the aorta (P〈0.05). In all patients affected by CAD we evaluated the PMN's expression of CD11b/CD18 membrane integrins. In these patients the increase in expression of CD11b/CD18 was statistically significant in comparison with the controls (P〈0.01). This increase in expression correlates with a higher aggregation (r=0.87, P〈0.001). The potential role of leukocytes, oxygen radicals, leukotrienes and granulocyte enzymes in the pathophysiology of myocardial injury due to regional ischemia and reperfusion is an area of intense investigation. This paper presents studies carried out in vivo which have been instrumental in demonstrating the role of granulocytes as mediators of myocardial ischemia.

Notes: Monadic (one sample served at a time, and all attributes rated for that sample) and simultaneous multiple (4 samples served together, and attributes rated one at a time across samples) presentation and evaluation procedures were compared in terms of descriptive profile generated, panel performance (ability to discriminate, reproducibility, concept alignment) and session duration, in a descriptive analysis of 9 milk chocolate samples by a panel of 18 trained judges. The sensory profiles obtained with the two presentation modes were very similar (as assessed by spider web and principal component plots). Time-wise, the simultaneous presentation procedure took significantly longer to complete (p〈0.001). Judges discriminated slightly better and were more reproducible with the simultaneous presentation mode, but quality of concept alignment did not differ between the two procedures. We conclude each method has its advantages and limitations, and choice of presentation procedure should be based on the type of descriptive analysis carried out and the time frame available.

Notes: Summary Tholeiitic basaltic and basaltic andesite dikes of Brasiliano (or PanAfrican) age (≈ 600 Ma) intrude the basement of the Nico Perez region, Uruguay. Major and trace element geochemistry of the basalts indicates that they suffered fractionation in shallow magma chambers. The variation in element ratios, which remain virtually unchanged during fractionation (K/Rb, Rb/Ba, Ba/Nb, La/Nb, Zr/Nb and Ti/Zr), indicate that the dikes are not strictly comagmatic. However, they have certain features in common: LILE and LREE enrichment with respect to HFSE and HREE; high Rb/Ba (〉 0.9) and Rb/Sr (〉 0.08); low K/Rb (〈 214); negative Nb and Ti anomalies (La n /Nb n 〉 2; Ba/Nb 〉 22 Ti/Zr 〈 60).87Sr/86Sr and143Nd/144Nd at 665 Ma are in the range 0.7052 – 0.7119 and 0.51158 – 0.51177, respectively. The lack of correlations between isotope and trace element variations indicate that these characteristics are not controlled by crustal contamination of the melts. They are interpreted as being due to the melting of an enriched mantle (C1) under the influence of a fluid-rich component (C2) which stabilized a Nb-retaining titanate phase in the residuum. Although this process may be related to a subduction environment, it is also possible that it occurred in an ensialic region by the interaction of deep mantle fluids with the lithospheric continental mantle. The parent mantle underlying the early Proterozoic (1.8 Ga) Florida region had isotope and geochemical characteristics which could evolve to the values observed in the adjacent Nico Perez region. It is therefore proposed that mantle enrichment took place in the early Proterozoic and that this mantle melted under the influence of fluids in the late Proterozoic to derive the Nico Perez dikes.

Notes: Summary Geochemical investigations have been carried out on the metabasites of the Ivrea-Verbano Zone (NW-Italy). The Ivrea-Verbano Zone is commonly considered to be a section through the lower continental crust. It is constituted by a steeply dipping sequence of metamorphic rocks (Kinzigitic Series), intruded by a mafic-ultramafic complex. The metabasites of the Kinzigitic Series have a meta-igneous origin. Their protoliths show tholeiitic affinity in the NW and central part of the zone and alkalic affinity in the SE. This fact together with the rock associations suggests that a variation of the paleogeographic environment from NW to SE occurs in the Ivrea-Verbano Zone.

Notes: Summary Corona structures occur in the upper units (UGAZ and UA) of the Niquelândia mafic-ultramafic complex (Central Goiás, Brazil), where olivine gabbros, gabbros, anorthosites and “amphibolites” are interlayered. In olivine gabbros, where the corona structures are most complex, primary igneous minerals are olivine, plagioclase ± clinopyroxene and ilmenite. The instability between olivine and plagioclase results in three types of coronas: 1) ol + pl → opx + (cpx + sp)sympl 2) ol + pl → opx + (amph + sp)sympl 3) ol + pl → opx + amph + gar In the second corona type the amphibole is pargasite; in the third type the amphibole approaches Mg-hornblende in composition. The occurrence of secondary amphibole indicates the presence of a fluid phase during re-equilibration. Reaction calculations, obtained by means of a “MIXING” program, show that the mineralogical changes in the three corona types may reasonably have occurred in a closed system (with the exception of the fluid phase). The chemical composition of the reacting igneous phases (especially the Mg/Fe2+ ratio of the mafic phases) constrains the composition of the products, but not the type of secondary assemblage. The nature of these products depends mainly on the variations ofaH2O, in relation to temperature decrease. In gabbros, anorthosites and “amphibolites”, where orthopyroxene and/or amphibole may be intercumulus phases, the following reactions occur between pyroxenes and plagioclase: 4) opx + cpx + pl → hbl 5) opx + cpx + pl → hbl + gar ± qz 6) opx + pl → cpx + gar + qz In these rocks, garnet formation as a product in reaction (5) depends on the partial pressure of a vapour phase. Reaction (6) develops only when the orthopyroxene is very iron-rich. Estimates of the re-equilibration pressure are of 5–8 kb; re-equilibration temperatures vary from about 800°C (anhydrous corona in olivine gabbros) to 560°C (plag + hbl + gar + qz secondary assemblages). Temperatures obtained from the hbl - gar geothermometer are directly correlated with the pargasitic component in secondary amphiboles. The absence of deformation suggests that the coronas formed during slow cooling and not during a metamorphic event. The present data do not provide an answer to the problem of whether H2O has been introduced from the country rocks or is of igneous origin.

Notes: [Auszug] The large mafic complex overlying mantle peridotites in the Ivrea Zone of northern Italy originated by underplating of mantle-derived magma onto the base of continental crust, and may be a unique outcrop of typical mafic lower crust, sampled elsewhere only by mafic xenoliths. Neodymium and ...

Notes: Abstract The Finero peridotite massif is a harzburgite that suffered a dramatic metasomatic enrichment resulting in the pervasive presence of amphibole and phlogopite and in the sporadic occurrence of apatite and carbonate (dolomite)-bearing domains. Pyroxenite (websterite) dykes also contain phlogopite and amphibole, but are rare. Peridotite bulk-rock composition retained highly depleted major element characteristics, but was enriched in K, Rb, Ba, Sr, LREE (light rare earth elements) (LaN/YbN = 8–17) and depleted in Nb. It has high radiogenic Sr (87Sr/86Sr(270) = 0.7055–0.7093), low radiogenic Nd (ɛNd(270) = −1 to −3) and EMII-like Pb isotopes. Two pyroxenite – peridotite sections examined in detail show the virtual absence of major and trace element gradients in the mineral phases. In both rock types, pyroxenes and olivines have the most unfertile major element composition observed in Ivrea peridotites, spinels are the richest in Cr, and amphibole is pargasite. Clinopyroxenes exhibit LREE-enriched patterns (LaN/YbN ∼16), negative Ti and Zr and generally positive Sr anomaly. Amphibole has similar characteristics, except a weak negative Sr anomaly, but incompatible element concentration ∼1.9 (Sr) to ∼7.9 (Ti) times higher than that of coexisting clinopyroxene. Marked geochemical gradients occur toward apatite and carbonate-bearing domains which are randomly distributed in both the sections examined. In these regions, pyroxenes and amphibole (edenite) are lower in mg## and higher in Na2O, and spinels and phlogopite are richer in Cr2O3. Both the mineral assemblage and the incompatible trace element characteristics of the mineral phases recall the typical signatures of “carbonatite” metasomatism (HFSE depletion, Sr, LILE and LREE enrichment). Clinopyroxene has higher REE and Sr concentrations than amphibole (amph/cpxDREE,Sr = 0.7–0.9) and lower Ti and Zr concentrations. It is proposed that the petrographic and geochemical features observed at Finero are consistent with a subduction environment. The lack of chemical gradients between pyroxenite and peridotite is explained by a model where melts derived from an eclogite-facies slab infiltrate the overhanging harzburgitic mantle wedge and, because of the special thermal structure of subduction zones, become heated to the temperature of the peridotite. If the resulting temperature is above that of the incipient melting of the hydrous peridotite system, the slab-derived melt equilibrates with the harzburgite and a crystal mush consisting of harzburgite and a silica saturated, hydrous melt is formed. During cooling, the crystal mush crystallizes producing the observed sequence of mineral phases and their observed chemical characteristics. In this context pyroxenites are regions of higher concentration of the melt in equilibrium with the harzburgite and not passage-ways through which exotic melts percolated. Only negligible chemical gradients can appear as an effect of the crystallization process, which also accounts for the high amphibole/clinopyroxene incompatible trace element ratios. The major element refractory composition is explained by an initially high peridotite/melt ratio. The apatite, carbonate-bearing domains are the result of the presence of some CO2 in the slab-derived melt. The CO2/H2O ratio in the peridotite mush increased by crystallization of hydrous phases (amphibole and phlogopite) locally resulting in the unmixing of a late carbonate fluid. The proposed scenario is consistent with subduction of probably Variscan age and with the occurrence of modal metasomatism before peridotite incorporation in the crust.