Glacial ice and atmospheric forcing on the Mertz Glacier Polynya over the past 250 years.

The Mertz Glacier Polynya off George V Land, East Antarctica, is a source of Adélie Land Bottom Water, which contributes up to ~25% of the Antarctic Bottom Water. This major polynya is closely linked to the presence of the Mertz Glacier Tongue that traps pack ice upstream. In 2010, the Mertz Glacier calved a massive iceberg, deeply impacting local sea ice conditions and dense shelf water formation. Here we provide the first detailed 250-year long reconstruction of local sea ice and bottom water conditions. Spectral analysis of the data sets reveals large and abrupt changes in sea surface and bottom water conditions with a ~70-year cyclicity, associated with the Mertz Glacier Tongue calving and regrowth dynamics. Geological data and atmospheric reanalysis, however, suggest that sea ice conditions in the polynya were also very sensitive to changes in surface winds in relation to the recent intensification of the Southern Annular Mode.

Autoxidative and photooxidative reactivity of highly branched isoprenoid (HBI) alkenes.

Autoxidation of several mono-, di-, tri- and tetra-unsaturated highly branched isoprenoid (HBI) alkenes was induced in organic solvents using a radical initiator and enhancer, and their degradation rates were compared to those of classical phytoplanktonic lipids (mono-unsaturated fatty acids, sterols and chlorophyll phytyl side-chain). Autoxidation of two HBI trienes was also investigated in senescent and highly photodegraded diatom cells, collected in the Antarctic, using Fe(2+) ions as radical inducers. Autoxidation rates of HBI alkenes were found to increase with the number of tri-substituted double bonds, as expected. Further, HBI trienes possessing one bis-allylic position (where hydrogen abstraction is highly favoured) were found to be particularly reactive towards autoxidation and degraded at similar rates compared to polyunsaturated fatty acids in diatom cells. By comparison of the autoxidation products of the most reactive tri-unsaturated HBI with the corresponding photooxidation products, some specific tracers of these two types of abiotic degradation processes were identified. The lack of reactivity of the mono-unsaturated HBI IP25 and a structurally similar di-unsaturated HBI towards autoxidative degradation supports the good preservation of these biomarkers in marine sediments.

Persistent organic pollutants in benthic and pelagic organisms off Adélie Land, Antarctica.

The concentrations of polychlorinated biphenyls (PCB), hexachlorobenzene (HCB), pentachlorobenzene (PeCB) and polybrominated diphenylethers (PBDE) were described in benthic and pelagic species collected off Adélie Land, Antarctica. Strong differences were observed among species, with reduced PeCB and HCB levels in benthic species, and elevated PCB levels in the Antarctic yellowbelly rockcod, the Antarctic sea urchin and the snow petrel. Lower-chlorinated congeners were predominant in krill; penta-PCBs in benthic organisms; hexa- and hepta-PCBs in seabirds and cryopelagic fish. This segregation may result from sedimentation process, specific accumulation and excretion, and/or biotransformation processes. The presence of PBDEs in Antarctic coastal organisms may originate from atmospheric transport and partly from a contamination by local sources. Although POP levels in Antarctic marine organisms were substantially lower than in Arctic and temperate organisms, very little is known about their toxic effects on these cold-adapted species, with high degree of endemism.

Rebound congestion and rhinitis medicamentosa: nasal decongestants in clinical practice. Critical review of the literature by a medical panel.

INTRODUCTION: Systemic and topical nasal decongestants are widely used in otorhinolaryngology and general practice for the management of acute rhinosinusitis and as an adjuvant in certain forms of chronic rhinosinusitis. These products, very effective to rapidly improve nasal congestion, are sometimes available over the counter and can be the subject of misuse, which is difficult to control. The Société Française d'ORL has recently issued guidelines concerning the use of these decongestants in the doctor's office and the operating room. MATERIALS AND METHODS: The review of the literature conducted by the task force studied in detail the concepts of "rebound congestion" and "rhinitis medicamentosa" often reported in a context of misuse, particularly of topical nasal decongestants. The clinical and histopathological consequences of prolonged and repeated use of nasal decongestants have been studied on animal models and healthy subjects. RESULTS: Discordant results have been obtained, as some authors reported a harmful effect of nasal decongestants on the nasal mucosa, while others did not identify any significant changes. No study has been able to distinguish between inflammatory lesions induced by chronic rhinosinusitis and lesions possibly related to the use of nasal decongestants. DISCUSSION: The task force explained the rebound congestion observed after stopping nasal decongestant treatment by return of the nasal congestion induced by rhinosinusitis and rejected the concept of rhinitis medicamentosa in the absence of scientific evidence from patients with rhinosinusitis. CONCLUSION: Nasal decongestants are recommended for the management of acute rhinosinusitis to reduce the consequences of often disabling nasal congestion. They are also recommended during rhinoscopic examination and for preparation of the nasal mucosa prior to endonasal surgery.

Pomegranate juice and pomegranate extract do not impair oral clearance of flurbiprofen in human volunteers: divergence from in vitro results.

Nutrient interactions with prescription drugs are a topic of ongoing basic and clinical research. Pomegranate juice and a 1-g capsule containing pomegranate extract were evaluated in vitro and in vivo as inhibitors of cytochrome P450 2C9 (CYP2C9), with flurbiprofen serving as the index substrate. Fluconazole was the positive control inhibitor. The in vitro 50% inhibitory concentration (IC(50)) values for pomegranate juice and extract were below 1% (vol/vol), with no evidence of mechanism-based (irreversible) inhibition. In clinical studies, flurbiprofen pharmacokinetics were unchanged by pomegranate juice or extract as compared to a low-polyphenol placebo control beverage. However, fluconazole significantly reduced the oral clearance of flurbiprofen. Despite inhibition of CYP2C9 in vitro, pomegranate juice and extract had no effect on CYP2C9 activity in human subjects, and can be consumed by patients taking CYP2C9 substrate drugs with negligible risk of a pharmacokinetic interaction.

Biosynthesis of unusual monocyclic alkenes by the diatom Rhizosolenia setigera (Brightwell).

Novel, polyunsaturated monocyclic sester- and triterpenes isolated from the diatom Rhizosolenia setigera (Brightwell), are biosynthesised mainly via the mevalonate pathway. The experiments involved incubation of the alga with [1-(13)C]acetate, isolation of the alkenes by extraction and silver ion HPLC, followed by determination of the labelling pattern of one of the monocyclic triterpenes by (13)C-NMR spectroscopy. In addition, the extent of (13)C incorporation was also measured by mass spectrometry which revealed that the involvement of the mevalonate route in the biosynthesis of these cyclic compounds was less than for the co-occurring acyclic highly branched isoprenoid alkenes.

A simple method for SEM examination of sectioned diatom frustules.

We describe an innovative yet straightforward method to obtain high quality thin sections of diatom exoskeletons for observation by scanning electron microscopy (SEM). The use of this new technique allows for clear observations of some ultrastructural valve features, including the raphe, which are generally difficult to observe and describe accurately using transmission electron microscopy analysis of thin sections or SEM of randomly fractured diatom valves. In addition, because this method involves the complete removal of the organic content of the diatom cells, resulting in clean and mostly undisturbed skeletal thin cross-sections, even the intact valvar structures of weak girdle bands can be studied.

Factors influencing the distributions of polyunsaturated terpenoids in the diatom, Rhizosolenia setigera.

Polyunsaturated highly branched isoprenoid (HBI) hydrocarbon distributions of laboratory cultures of five strains of the planktonic diatom Rhizosolenia setigera (Brightwell) are shown herein to be highly variable. Some strains produced both haslenes with from three to five double bonds and rhizenes. The haslenes comprised not only Delta5 alkenes but also those with C7(20) unsaturation, including hasla-7(20),9E,Z, 23-trienes and hasla-7(20),9E,Z-13, 23-tetraenes. The rhizenes contained C7(25) unsaturation and the vinyl moiety common to all algal haslenes so far characterised. The effects of temperature and salinity on HBI composition, along with isotopic content, were determined in strain CS 389/A. Increase in growth temperature from 18 to 25 degrees C increased the degree of unsaturation in the haslenes and E to Z isomerisation in the triene. There was also an increase in unsaturation in the rhizenes at the highest growth temperature, with hexaenes dominant over the pentaenes but in the rhizenes, Z to E isomerisation increased. Increased salinity from 15 to 35 psu increased cell growth and rhizene production but decreased haslene production. Unsaturation in haslenes was not changed by increased salinity but unsaturation in the rhizenes decreased. These may reflect growth rate differences. The carbon isotopic compositions of the haslenes and rhizenes were similar to that of the major sterol at 18 degrees C, but the major HBI isomers were 3-4 per mil depleted relative to phytol released by saponification from chlorophyll a. This suggests biosynthesis of HBIs from a different isotopic pool of isopentenyl biphosphate to that from which phytol is biosynthesised. At 25 degrees C, further isotopic differences were observed. The variables controlling HBI distributions in R. setigera are still not fully understood and rationalisation of the environmental controls on the sedimentary distributions of the HBIs from R. setigera may only be possible once such factors are established.

Haslea salstonica sp. nov. and Haslea pseudostrearia sp. nov. (Bacillariophyta), two new epibenthic diatoms from the Kingsbridge estuary, United Kingdom.

Two new diatom species, Haslea salstonica and Haslea pseudostrearia are described in light and electron microscopy and compared with two well-known members of Haslea. Scanning electron microscope observations confirm that the new species belong to the genus Haslea. This study extends previous observations on the genus, particularly with respect to the development of a pseudostauros. The characteristic features of the genus are discussed briefly.

Variable stereochemistry in highly branched isoprenoids from diatoms.

C(25) highly branched isoprenoid (HBI) alkenes are ubiquitous lipids found in geochemical samples around the globe. The origins of these widespread geochemicals are believed to be restricted to a limited number of diatoms, including Haslea ostrearia (and related species), Rhizosolenia setigera, and Pleurosigma intermedium. The unsaturation of the HBI alkenes ranges from 2-6 in different species and cultures. The number of stereogenic centres is usually limited to two in the HBI alkenes due to double bond positions. The relative and/or absolute configurations for these have been determined for a range of HBI alkenes produced from different diatoms cultured under a number of growth conditions. These determinations have involved a combined spectroscopic and chromatographic analysis using NMR spectroscopy and chiral gas chromatography, respectively. HBIs isolated from Haslea spp. belong to a specific structural type which exhibit configurational diastereoisomerism, while those isolated from P. intermedium and R. setigera represent a different structural type and usually exist as mixtures of geometric isomers only. HBIs are reported from a new species of diatom whose stereochemical properties lie between those found for Haslea spp. and P. intermedium.

Effects of temperature on polyunsaturation in cytostatic lipids of Haslea ostrearia.

Unusual chemicals produced by the-'blue oyster' diatom, Haslea ostrearia, include the water-soluble blue pigment marennine and numerous polyunsaturated sesterterpene oils or haslenes. Aqueous extracts of the alga exhibit in vitro and in vivo activities against human lung cancer cells and anti-HIV effects. Here we report that three haslenes also demonstrate in vitro cytostatic action against a human lung cancer cell line. The most active haslene is the most unsaturated and unsaturation in the haslenes increases with increasing algal growth temperature.

Tetra-unsaturated sesterterpenoids (Haslenes) from Haslea ostrearia and related species.

The structures and distributions of C25 highly branched isoprenoid (HBI) alkenes (Haslenes) have been determined following isolation from cultures of the diatoms Haslea ostrearia, Haslea crucigera, Haslea pseudostrearia and Haslea saltstonica. The distributions of the HBIs change between Haslea species and also between different cultures of the same species. Large scale culturing of H. ostrearia and H. pseudostrearia has enabled the structures of three new tetra-unsaturated alkenes to be determined by NMR spectroscopy. The structural relationships between different Haslenes together with the potential significance of the biosynthesis of HBIs by the Haslea genus is discussed.

Configurations of polyunsaturated sesterterpenoids from the diatom, Haslea ostrearia.

The partial configurations of C25 isoprenoid alkenes isolated from the diatom Haslea ostrearia Gaillon (Simonsen) have been established. A combination of NMR spectroscopy studies of the alkenes with chiral shift reagents in conjunction with soluble silver beta-diketonate complexes and enantioselective gas chromatography of oxidation products of the alkenes was used. Unexpected differences in highly branched isoprenoid isomer configurations were observed between different laboratory cultures of the alga.

Antitumor and antiproliferative effects of an aqueous extract from the marine diatom Haslea ostrearia (Simonsen) against solid tumors: lung carcinoma (NSCLC-N6), kidney carcinoma (E39) and melanoma (M96) cell lines.

An aqueous extract of the marine diatom Haslea ostrearia (Simonsen) was studied for its antiproliferative properties against human solid tumors: lung carcinoma (NSCLC-N6), kidney carcinoma (E39) and melanoma (M96). These types of carcinoma are particularly chemoresistant. The extract has a potent cytostatic effect in vitro on the three cell lines and blocks the NSCLC-N6 line in the G1/S phase of the cell cycle. Moreover, the extract strongly inhibits tumor growth of NSCLC-N6 bearing nude mice. These preliminary results indicate that the aqueous extract of Haslea ostrearia exhibits inhibitory effects both in vitro and in vivo against solid carcinoma lines, suggesting the presence of a new potent antitumor agent in the aqueous algal homogenate.

Acetabular osteoblastoma: description of a case.

Osteoblastoma is a slow-progressing, benign bone tumor, that is not frequently observed in clinical orthopaedics (approximately 1% of all primary bone tumors). There is predilection for the vertebrae (posterior arch), the femur, the tibia, and the cranium; it affects young subjects (from 10 to 35 years), with predilection for males (males: females = 2:1). Symptoms are not very specific, characterized essentially by moderate, discontinuous pain, that is responsive to treatment by NSAIDS; it may, at times, be asymptomatic. On radiographic assessment it is viewed as a lytic area that is rounded, greater than 2 cm in size, with unclear margins, with or without peripheral bone reaction. It is not easy to diagnose osteoblastoma, particularly if it is localized in unusual sites, such as in the pelvis. The authors present a case of osteoblastoma of the acetabular bottom in a subject aged 22 years, that was not diagnosed unrecognized for about 2 years from the onset of symptoms.

The prion protein gene is dispensable for the development of spongiform myeloencephalopathy induced by the neurovirulent Cas-Br-E murine leukemia virus.

The Cas-Br-E murine leukemia virus (MuLV) induces paralysis in susceptible mice that is accompanied by a severe spongiform myeloencephalopathy. These neurodegenerative lesions are very similar to those observed in prion diseases. To determine whether the prion protein gene (Prn-p) product was a downstream effector of this neurovirulent MuLV, we inoculated Prn-p(-/-) knockout homozygote and control heterozygote or wild-type mice with this retrovirus. All groups developed typical paralysis and spongiform encephalopathy, and no differences in clinical or histological phenotypes were observed between these groups. These results indicate that the Cas-Br-E MuLV does not require the prion protein to induce lesions. Thus, MuLV and prion proteins may induce a very similar disease through distinct pathways, or the viral Env protein, which harbors the primary determinant of pathogenicity, may act in a common pathway but downstream of the prion protein.

[Mental health prospects in France]. / Perspectives de la santé mentale en France.

In a developed country as ours, 30 % of the nursing care has to do with a psychological approach. The problem therefore concerns the whole of the medical system and is a problem linked to a global approach, overstepping the psyche/soma dichotomy. An important part of the health expenses in France (13 %) is assigned to the three components of medical discipline split into public activities, liberal and associative, with no real interconnections. Psychiatry appears balanced and strong as to its capacities of response (stabilisation of psychoses, curative capacities for many clinical cases) but suffers a number of "handicaps", particularly, but not solely in what concerns its public component. If, indeed, priority and orientations have been constantly defined, they appear insufficiently relayed and attended to. It is important in duration and in order to remain loyal to it, to give further thought to sector politics, in preserving the conceptual assets (permanence of care, open care network) developing its limits (rigidness of equipments, lack of respect of the logics of the flow) and to promote trans or intersectorial steps in the field of organization (emergency and liaison) or the approach to certain claims or pathologies. Such re-definition must concern the field competence and complementarities of general medicine, of private specialists, sectorised, intersectorised or non sectorised publics; the indications of full time hospitalisation and other means of taking charge ; the sanitary articulation : social and medicosocial (separating what is relevant to care, assistance and sheltering). Expected, better and better understood levers relate to managing as well as initial and continuous training of professionals, with the aim of attending the change of structures, including evaluation, communication and research. In our country, no technical reason does valuably oppose to the rapid implementation of a global process of development, able to meet the needs of patients but also of professionals whatever their means of practice may be.