A propos de quelques groupements végétaux observés entre monaco et gênes

Résumé Le climat chaud et humide de la Ligurie méditerranéenne détermine la réapparition de quelques groupements végétaux connus de la Catalogne et rares ou nuls en Languedoc: Inulo-Oryzopsietum miliaceae, Cichorio-Sporoboletum poiretii, Hyparrhenietum hirto-pubescentis, Rubo-Coriarietum.Le caractère particulier de la végétation ligure a été exprimé par des groupements spéciaux: Pistacio-Rhamnetum alaterni, qui remplace le Quercetum cocciferae, groupements à Ostrya carpinifolia et à Brachypodium pinnatum des endroits frais, groupements buissonnants à Erica arborea et Genista germanica, à Rosmarinus et Genista cinerea, Asplenio-Campanuletum macrorhizae des rochers, etc.

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Summary The warm and humid climate of the Mediterranean Liguria determines the reappearance of some communities, known in Catalonia, and seldom or not existing in Languedoc: Inulo-Oryzopsietum miliaceae, Cichorio-Sporoboletum poiretii, Hyparrhenietum hirto-pubescentis, Rubo-Coriarietum.The particular character of the Liguric vegetation is expressed in special communities: Pistacio-Rhamnetum alaterni, which replaces the Quercetum cocciferae, communities with Ostrya carpinifolia and with Brachypodium pinnatum in the fresh places, bushy communities with Erica arborea and Genista germanica, with Rosmarinus and Genista cinerea, Asplenio-Campanuletum macrorhizae of the rocks, and so on.

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Zusammenfassung Das warme und feuchte Klima der mediterranen Ligurie bestimmt das Wiedererscheinen einiger Pflanzengesellschaften, die in Katalonien bekannt sind, aber selten oder nicht in Languedoc vorkommen: Inulo-Oryzopsietum miliaceae, Cichorio-Sporoboletum poiretii, Hyparrhenietum hirto-pubescentis, Rubo-Coriarietum.Der eigenartige Charakter der ligurischen Vegetation ist in besonderen Pflanzengesellschaften ausgedrückt: Pistacio-Rhamnetum alaterni, das das Quercetum cocciferae ersetzt, Gesellschaften mit Ostrya carpinifolia und mit Brachypodium pinnatum der frischen Standorte, Erica arborea-Genista germanica-Silikatbodengebüsche, Rosmarinus-Genista cinerea-Kalkbodengebüsche, Asplenio-Campanuletum macrorhizae der Felsen usw.

     

High-grade mucoepidermoid carcinoma of the breast. Fine needle aspiration cytology and clinicopathologic study of a case

A primary high-grade mucoepidermoid carcinoma of the breast was evaluated preoperatively by fine needle aspiration (FNA) cytology in a 72-year-old woman. The smears showed a mixed pattern consisting of clusters of poorly differentiated squamous cells, keratinized squamous cells and vacuolated mucin-secreting cells. The subsequent mastectomy specimen showed a tumor with the features of a high-grade mucoepidermoid carcinoma. Electron microscopy confirmed the diagnosis, reflecting the epidermoid and glandular differentiation of the tumor. The course was rapidly fatal, and the patient died a few months after presentation. A review of the literature indicated that mucoepidermoid carcinoma of the breast is a very rare neoplasm; the FNA cytologic features described in this report may constitute a basis to preoperatively recognize this tumor.     

"Caged calcium" in Aplysia pacemaker neurons. Characterization of calcium-activated potassium and nonspecific cation currents

We have studied calcium-activated potassium current, IK(Ca), and calcium-activated nonspecific cation current, INS(Ca), in Aplysia bursting pacemaker neurons, using photolysis of a calcium chelator (nitr-5 or nitr-7) to release "caged calcium" intracellularly. A computer model of nitr photolysis, multiple buffer equilibration, and active calcium extrusion was developed to predict volume-average and front-surface calcium concentration transients. Changes in arsenazo III absorbance were used to measure calcium concentration changes caused by nitr photolysis in microcuvettes. Our model predicted the calcium increments caused by successive flashes, and their dependence on calcium loading, nitr concentration, and light intensity. Flashes also triggered the predicted calcium concentration jumps in neurons filled with nitr-arsenazo III mixtures. In physiological experiments, calcium-activated currents were recorded under voltage clamp in response to flashes of different intensity. Both IK(Ca) and INS(Ca) depended linearly without saturation upon calcium concentration jumps of 0.1-20 microM. Peak membrane currents in neurons exposed to repeated flashes first increased and then declined much like the arsenazo III absorbance changes in vitro, which also indicates a first-order calcium activation. Each flash-evoked current rose rapidly to a peak and decayed to half in 3-12 s. Our model mimicked this behavior when it included diffusion of calcium and nitr perpendicular to the surface of the neuron facing the flashlamp. Na/Ca exchange extruding about 1 pmol of calcium per square centimeter per second per micromolar free calcium appeared to speed the decline of calcium-activated membrane currents. Over a range of different membrane potentials, IK(Ca) and INS(Ca) decayed at similar rates, indicating similar calcium stoichiometries independent of voltage. IK(Ca), but not INS(Ca), relaxes exponentially to a different level when the voltage is suddenly changed. We have estimated voltage-dependent rate constants for a one-step first-order reaction scheme of the activation of IK(Ca) by calcium. After a depolarizing pulse, INS(Ca) decays at a rate that is well predicted by a model of diffusion of calcium away from the inner membrane surface after it has entered the cell, with active extrusion by surface pumps and uptake into organelles. IK(Ca) decays somewhat faster than INS(Ca) after a depolarization, because of its voltage-dependent relaxation combined with the decay of submembrane calcium. The interplay of these two currents accounts for the calcium-dependent outward-inward tail current sequence after a depolarization, and the corresponding afterpotentials after a burst