Functional Effects of Adiponectin on Endothelial Progenitor Cells

Adiponectin is an adipokine whose plasma levels are inversely correlated to metabolic syndrome components. Adiponectin protects against atherosclerosis and decreases risks in myocardial infarction. Endothelial progenitor cells (EPCs) are a heterogeneous population of circulating cells involved in vascular repair and neovascularization. EPCs number is reduced in patients with cardiovascular disease. We hypothesize that the positive effects of adiponectin against atherosclerosis are explained in part by its interactions with EPCs. Cells were obtained from healthy volunteers' blood by mononuclear cell isolation and plating on collagen‐coated dishes. Three sub‐populations of EPCs were identified and characterized using flow cytometry. EPCs' expression of adiponectin receptors, AdipoR1, and AdipoR2 was evaluated by quantitative PCR. The effects of recombinant adiponectin on EPCs' susceptibility to apoptosis were assessed. Finally, expression of neutrophil elastase by EPCs and activity of this enzyme on adiponectin processing were assessed. Quantitative PCR analysis of EPCs mRNAs showed that AdipoR1 mRNA is expressed at higher levels than AdipoR2. Expression of AdipoR1 protein was confirmed by western blot. Adiponectin significantly increased survival of two sub‐populations of EPCs in conditions of serum deprivation. Such effect could not be demonstrated in the third EPCs sub‐population. We also demonstrated that EPCs, particularly one sub‐population, express neutrophil elastase. Neutrophil elastase activity was confirmed in EPCs' conditioned media. Adiponectin protects some EPCs sub‐populations against apoptosis and therefore could modulate EPCs ability to induce repair of vascular damage. Neutrophil elastase activity of EPCs could locally modulate adiponectin activity by its involvement in the generation of the globular form of adiponectin.     

Ecology and biogeography of plant communities associated with the post Plio-Pleistocene relict Rhododendron ponticum subsp. baeticum in southern Spain

Aims Rhododendron ponticum L. is reputed to be a post Plio‐Pleistocene relict plant species with a disjunct distribution that comprises the Iberian Peninsula to the west and the Euxinian region plus some restricted Mediterranean areas to the east. We analysed the ecological range (of subsp. baeticum) in the western area (Aljibe Mountains, north of the Strait of Gibraltar) to understand the factors determining the present area limitation. Location Sierra del Aljibe, north of the Strait of Gibraltar (Iberian Peninsula). Methods We selected 20 riparian sites where R. ponticum is common, and compiled data on the ecological diversity of associated woody species and ferns. We established a 500‐m main transect in each site, along the stream or river course, in which we placed five 20‐m‐long plots at regular intervals. We recorded physiographic habitat features, woody plants and fern abundance, and the number of R. ponticum individuals. Results Rhododendron ponticum in southern Spain is restricted to riparian forests in acidic soils (pH 4.0–6.4), and is mainly found on the banks of inclined and enclosed streams. In our inventory we recorded 59 woody taxa and 12 ferns, with R. ponticum being the dominant species of the understorey (mean abundance 78.6%). The communities are characterized by a high incidence of the humid warm temperate element, both in number of species (18.8 ± 3.7 per site) and abundance; meanwhile, the presence of the modern Mediterranean element (mean number of species 3.4 ± 3.8 per site) appears to be favoured by disturbance. These ecological–historical groups of taxa also show distinct patterns of typological habit, frequency of endemism, infrageneric diversity and geographical range. Populations of R. ponticum are characterized by a very variable density of seedlings in many sites, and the virtual lack of juveniles. Main conclusions Riparian forests of the Aljibe Mountains constitute a refuge for R. ponticum where the species persists, but populations appear to be in decline. The narrow ecological range of R. ponticum in the area strongly contrasts with its wide amplitude in the eastern natural area, mainly the Euxinian region, where R. ponticum probably finds better conditions due to the environmental heterogeneity of the region, and the lack of a hot dry season.     

Voltage-dependent channels permeable to K+ and Na+ in the membrane ofAcer pseudoplatanus vacuoles

Summary The patch-clamp technique in whole-cell configuration was used to study the electrical properties of the tonoplast in isolated vacuoles fromAcer pseudoplatanus cultured cells. In symmetrical KCl or K₂ malate solutions, voltage- and time-dependent inward currents were elicited by hyperpolarizing the tonoplast (inside negative), while in the positive range of potential the conductance was very small. The specific conductance of the tonoplast at –100 mV, in 100mm symmetrical KCl was about 160 S/cm². The reversal potentials (E _rev) of the current, measured in symmetrical or asymmetrical ion concentrations (cation, anion or both) were very close to the values of the K⁺ equilibrium potential. Experiments performed in symmetrical or asymmetrical NaCl indicate that Na⁺ too can flow through the channels. NeitherE _rev nor amplitude and kinetics of the current changed by replacing NaCl with KCl in the external solution. These results indicate the presence of hyperpolarization-activated channels in tonoplasts, which are permeable to K⁺ as well as to Na⁺. Anions such as Cl^– or malate seem to contribute little to the channel current.     

A new technique for the treatment of palpebral bags

A new technique for the treatment of palpebral bags is presented. The technique consists of returning fat to the orbital cavity and retaining it by means of a continuous suture (with nonabsorbable filament) of the capsulopalpebral fascia to the periosteum of the lower orbital rim. The anatomic basis for the technique, after examination of the relevant literature and dissection on fresh cadavers, is analyzed. The procedure followed and results obtained are described in detail. Evaluation of the results suggests to the authors that this might be the method to be applied in the majority of patients.     

The effects of polyinosinic:polycytidylic acid (pI:C) on the graft-vs-host (GVH) reaction. II. Increased NK-mediated rejection on C57BL/6 lymphocytes by (C57BL/6 X A)F1 mice

We previously demonstrated that treatment of (C57BL/6 X A)F1 (F1) recipient mice with polyinosinic:polycytidylic acid (pI:C) before injection with 30 X 10(6) C57BL/6 (B6) lymphocytes prevents both the immunosuppression and pathologic lesions typical of graft-vs-host (GVH) reactions. We now report the further characterization of this phenomenon. Donor spleen and lymph node cells were labeled with fluorescein in vitro and injected into pI:C-treated or untreated mice. Two days later, recipient splenocytes were analyzed for the presence of fluorescein-labeled donor cells by flow microfluorometry. Treatment of F1 mice with pI:C resulted in a sharp reduction in the recovery of labeled B6 but not A strain parental cells. Treatment with pI:C had no effect when syngeneic recipients were used, or when F1 cells were injected into A, B6, or F1 recipients. These results suggest that pI:C treatment induces rejection of B6 but not A or F1 lymphocytes by F1 hybrid mice at least as early as 2 days after donor cell transfer. As F1 cells are not rejected by either parent, rejection does not seem to be directed against classical alloantigens. These observations are compatible with the previously described model of hybrid resistance (HR) against bone marrow grafts. The rapidity of rejection strongly suggested that natural cytotoxic mechanisms were involved, thus, natural killer (NK) cell and macrophage (M phi) cytotoxic activities were tested throughout the time when the parental cell graft was being rejected. Over this period, pI:C treatment increased cytotoxic activity against the NK-sensitive target cell line YAC-1 but had no effect on spontaneous M phi tumoricidal activity against the L5178Y and MDAY-D2 cell lines. The results suggest that NK cells, but not M phi, may be involved in the elimination of B6 parental cells by the pI:C-treated F1 mice. NK cells have been demonstrated to be radioresistant; thus, as a test of our hypothesis, we examined the effects of irradiation on the capacity of pI:C treated F1 mice to reject B6 lymphocytes. The results show that this capacity was not blocked by 750 cGy, a dose of radiation that abrogates most T and B cell functions. Furthermore, rejection of parental cells could be prevented by treatment of recipient F1 mice with antibodies to asialo GM1, a treatment that suppresses NK activity. These data demonstrate that pI:C-mediated protection from GVH-induced changes is due to increased rejection of grafted B6 parental cells by F1 NK cells, a phenomenon very similar, if not identical, to HR to bone marrow grafts.     

Analysis of lumped and distributed elements models of cut muscle fibers in vaseline or sucrose gap preparations

A general method of finding the time course and the steady state distribution of potential in Vaseline or sucrose gap preparations is given by making use of the linear cable equation. The general solution has been found analytically in terms of its Laplace transform and then numerically inverted. Two particular experimental situations, namely the single gap and the double gap preparations, have been analyzed. The results have been compared with the solutions of the commonly used lumped elements models. While for the double gap no large errors are introduced by the lumped model, for the single gap there are significant differences. The dependence of the voltage distribution on various electrical and geometrical parameters has been examined. It is suggested that the proposed mathematical treatment might be used by experimenters as a reference to assess the validity of simplified lumped models.     

A taximetric study of infraspecific variation in autogamous Limnanthes floccosa (Limnanthaceae)

Limnanthes floccosa Howell is a variable autogamous species of recent origin. The phenetic relationships of a large number of populations ofL. floccosa were studied using taximetric techniques. Five subspecies are recognized inL. floccosa on the basis of the taximetric results.Limnanthes floccosa ssp.californica andL. floccosa ssp.grandiflora are described as new, andL. floccosa ssp.pumila andL. floccosa ssp.bellingeriana are proposed as new combinations. Aspects of autogamy responsible for the highly discrete pattern of variation inL. floccosa are discussed.