The wave regimes of the Central Pacific Ocean with a focus on pearl farming atolls.

Pearl farming sustainability in South Central Pacific (SCP) atolls strongly depends on water quality and renewal. These factors are partly controlled by the wave conditions that impact the lagoon circulation. To characterize the wave conditions around 83 SCP atolls including those hosting pearl farming activities, we used 18 years of WaveWatchIII simulation with a grid refined from 50 to 5 km resolution. Three regional wave regimes are statistically identified: two associated with long distant swells originating from mid-latitude storms, and one with local trade winds. All regimes occur with a relatively high frequency (22-44%), but with a marked seasonality. Wave conditions are also strongly modified locally during their propagation between the archipelagoes. Western and southern isolated atolls generally have a single regime all around their rims. In contrast, central Tuamotu atolls experience different regimes depending on their levels of protection. These results help understanding atoll hydrodynamics, which has implications for their management.

Characterization of south central Pacific Ocean wind regimes in present and future climate for pearl farming application.

In the South Pacific (SP) pearl farming atolls, wind is the main driver of lagoon water circulation, affecting dispersal and survival of pearl oyster larvae. To characterize typical wind conditions in the SP, wind regime classifications are performed from regional climate simulations using the WRF model, for present-day and for the end of the 21st century under RCP8.5 scenario conditions. At the daily time-scale, 4 regimes are identified: a trade-wind, a north-easterly, and two easterly regimes. Their characteristics are driven by large-scale circulation and climate modes of variability. In future projection, all regimes are characterized by a ~15% wind speed increase, while directions and occurrence frequencies undergo marginal changes. At the monthly time-scale that corresponds to pearl oyster pelagic larval duration, nine wind regimes are determined including three regimes with wind reversals. These regimes can be used to model typical lagoon conditions during larval dispersal.

Impact of projected sea surface temperature biases on tropical cyclones projections in the South Pacific.

Climate model projections generally indicate fewer but more intense tropical cyclones (TCs) in response to increasing anthropogenic emissions. However these simulations suffer from long-standing biases in their Sea Surface Temperature (SST). While most studies investigating future changes in TC activity using high-resolution atmospheric models correct for the present-day SST bias, they do not consider the reliability of the projected SST changes from global climate models. The present study illustrates that future South Pacific TC activity changes are strongly sensitive to correcting the projected SST changes using an emergent constraint method. This additional correction indeed leads to a strong reduction of the cyclogenesis (-55%) over the South Pacific basin, while no statistically significant change arises in the uncorrected simulations. Cyclogenesis indices suggest that this strong reduction in the corrected experiment is caused by stronger vertical wind shear in response to a South Pacific Convergence Zone equatorward shift. We thus find that uncertainty in the projected SST patterns could strongly hamper the reliability of South Pacific TC projections. The strong sensitivity found in the current study will need to be investigated with other models, observational constraint methods and in other TC basins in order to assess the reliability of regional TC projections.

[A structured ePortfolio to handle a programme of professional competences assessment in the area of transfusion medicine]. / Un portfolio électronique structuré pour la gestion et le suivi des dossiers d'évaluation des pratiques professionnelles en technique et médecine transfusionnelles.

In order to organize a nationwide program for the evaluation of professional practices in the area of blood transfusion, the French National Blood Transfusion Institute and the Nice-Sophia Antipolis University designed and implemented a web based service aimed at following-up and guiding the physicians involved in such an assessment program. The core component is a structured electronic portfolio (ePortfolio), the implementation of which was based on an object-oriented environment combined with a content management system. The modelling of the global evaluation system makes it possible to describe this type of portfolio according to six axes: an axis "objectives" (competencies accreditation); an axis "target" (heath care professionals); an axis "content" (numerical documents); an axis "structure" (matrix of answer defined in space and time); an axis "source" (single source peer-reviewed); an axis "level of evidence" (validation of the proof after its deposit by an identified and authenticated peer user, whole tracking of the exchanges and interactions between users and device).

Long-term tolerance of preservative-free eye drops containing macrogol hydroxystearate as an excipient.

PURPOSE: This in vivo animal study was conducted to assess the tolerability of macrogloglycerol hydrostearate 40 (MGH 40), commonly used as a solubilizing excipient in prostaglandin F2α analogue eye drops without benzalkonium chloride. METHODS: Twenty-eight (14 males and 14 females) New Zealand white albino rabbits in good health and with no signs of ocular irritation were randomly assigned to receive 25 µL instillations of a solution containing 10% MGH 40 in the right eye 3 times daily for either 3 or 6 months. Ocular examinations of the conjunctiva, cornea and iris (using an ophthalmoscope and slit-lamp), corneal sensitivity, and intraocular pressure were assessed in both the right (treated) and left (untreated) eyes throughout the study. General characteristics, hematology and serum biochemistry parameters were also assessed throughout the study and necropsy examinations were performed at study completion. RESULTS: There were no treatment-related effects on the cornea, conjunctiva, iris, or intraocular pressure. Transient findings were generally seen in the untreated as well as the treated eye. Similarly, there were no treatment-related findings in either the hematology or serum biochemistry data or at necropsy. There were no differences based on gender. CONCLUSIONS: Long-term administration of a 10% MGH 40-containing formulation three times per day in a standard in vivo animal model was well tolerated and had no ocular or other effect.

Affinity of amphotericin B for phosphatidylcholine vesicles as a determinant of the in vitro cellular toxicity of liposomal preparations.

Candida albicans and human erythrocytes were treated with liposomal amphotericin B (AmB) obtained by incubation of free AmB with small unilamellar vesicles (SUV) composed of unsaturated fatty acyl chains phosphatidylcholine (egg-yolk PC). Cellular effects were determined by changes in the K+ internal content of cells and in the number of colonies formed by fungal cells or as hemolysis, measured as a decrease in haemoglobin retention by erythrocytes. Dose-response curves were obtained by two procedures: either the ratio of AmB to phospholipids was kept constant over the AmB concentration range used (R = 10(-2] or the phospholipid concentration was kept constant (C = 0.2 mM) and the concentration of AmB varied. The liposomal preparations of AmB were as active against fungi as AmB in dimethylsulfoxide but less active (internal K+ changes) or inactive (hemolysis) against erythrocytes. On the other hand the binding of AmB to the SUV, as a function of the AmB concentration, was monitored by circular dichroism, fluorescence and UV absorption, in the two conditions used for the cellular studies. The amount of AmB bound when the total concentration of antibiotic was 2.10(-7) M was very low but increased with concentration and reached 90% at 10(-5) M. In all the assays we used, the anticellular effects could be attributed to the levels of AmB remaining free (unbound to the lipids). The variations of these levels with total AmB concentration could therefore explain the increased selectivity of liposomal AmB in toxicity against fungi and erythrocytes as compared to that of AmB added as a solution in dimethylsulfoxide. Indeed fungal cells are sensitive to low concentrations of AmB in dimethylsulfoxide; at these concentrations, in liposomal preparations, AmB is not bound to phospholipids and therefore as active as if added in dimethylsulfoxide. By contrast erythrocytes are only sensitive to much higher concentrations of AmB in dimethylsulfoxide; at these concentrations AmB is almost totally bound to phospholipids and therefore much less active.

[Tachistoscopy: an experimental method for studying cerebral hemispheric specialization]. / La tachistoscopie: une méthode expérimentale d'étude de la spécialisation hémisphérique.

Tachistoscopy is an experimental method used to study processes involved in hemispheric specialisation and the lateralisation of cerebral functions. The authors review the various findings emerging from this technique and briefly assess its methodological constraints.

Circular dichroism for the determination of amphotericin B binding to liposomes.

Circular dichroism (CD) of the antifungal antibiotic amphotericin B (AmB) can be used to characterize the liposomal preparations of the drug with regard to the levels of drug bound to the lipids. The very intense dichroic doublet centered around 340 nm of free amphotericin B in water or the dichroism observed above 435 nm can be used to determine the percentages of bound AmB and free AmB in preparations containing high antibiotic/lipid ratios (ranging from 10(-2) to 10(-1] used in these carrier systems. Examples are given for AmB in the presence of small unilamellar vesicles prepared from four saturated fatty acyl chain phosphatidylcholines of different chain lengths, with or without cholesterol. The transfer of AmB from vesicles to two blood components, serum albumin, and lipoproteins can also be monitored by CD under particular conditions.

Inhibition of erythrocyte ghost ATPase by polyene antibiotics.

The effect of micromolar concentrations of polyene antibiotics on erythrocyte ghost ATPase activities has been studied. (Mg2+)-ATPase is inhibited by amphotericin B and amphotericin B methyl ester, whereas (Na+ + K+ + Mg2+)-ATPase is inhibited by amphotericin B and lucensomycin. (Ca2+ + Mg2+)-ATPase is only slightly affected by polyene antibiotics.

Effects of polyene macrolides on the membrane potential of resting and activated human leukocytes.

Membrane potential changes in human polymorphonuclear leukocytes have been studied by monitoring the fluorescence signal of a carbocyanine probe in the presence of calcium ionophore A23187, chemotactic tripeptide f-met-leu-phe, and polyene macrolides. Reduction of the signals triggered by the ionophore and the tripeptide, inhibition of the respiratory burst, and changes in the Na+ influx into the cell seem to be the dominant effect of the polyenes. Polyene-induced depolarization does not correlate with the inhibition of the respiratory burst.

Study of the effects of liposomal amphotericin B on Candida albicans, Cryptococcus neoformans, and erythrocytes by using small unilamellar vesicles prepared from saturated phospholipids.

We compared the anticellular effects of liposomal amphotericin B (AmB) formed from AmB and small unilamellar vesicles. The small unilamellar vesicles with or without cholesterol were prepared from three L-alpha-phosphatidylcholines with saturated acyl chains of different lengths: distearoyl (C18), dipalmitoyl (C16), and dimyristoyl (C14). We found that the anticellular potency of liposomal AmB, compared with that of free AmB, decreased with decreasing length of the acyl chain of the phospholipid and increased with the addition of cholesterol. In a parallel study (S. Jullien, A. Vertut-Croquin, J. Brajtburg, and J. Bolard, Anal. Biochem. 172:197-202, 1988), we found that binding of AmB to vesicles decreased with increasing length of the acyl chain of the phospholipid and decreased with the addition of cholesterol. We conclude that the anticellular effects of liposomal AmB preparations are due to the levels of AmB remaining free (unbound to the lipids) in these preparations.