Effects of harmful dinoflagellate Ostreopsis cf. ovata exposure on immunological, histological and oxidative responses of mussels Mytilus galloprovincialis.

In the last decade massive blooms of the Ostreopsis cf. ovata have occurred in the Mediterranean basin, posing great concern to both environmental and human health. Biotoxicological and chemical studies demonstrated that O. cf. ovata produces palytoxin and ovatoxins; besides direct respiratory effects on humans due to inhalation of marine toxic aerosols, O. cf. ovata blooms can cause adverse effects on benthic invertebrates. The main aim of this study was to highlight the role of immunological, cellular and oxidative mechanisms in modulating the toxicity induced by O. cf. ovata in mussels Mytilus galloprovincialis. Organisms were exposed in laboratory condition to O. cf. ovata and analysed after 7 and 14 days of exposure. Obtained results demonstrated a clear involvement of the immune system with a significant decrement of granulocytes respect to the hyalinocytes type cells, a diminished phagocytosis activity and a reduced lysosomal membrane stability in haemocytes, after both 7 and 14 days of exposure. Histological analyses showed a decrease of the digestive gland wall thickness, dilatation of the tubules, haemocytes infiltration into the digestive gland and a decrement of neutral lipid levels in exposed mussels; similar results suggest a possible inhibition of the feeding activity, with a consequent induction of authophagic phenomena and utilization of stored reserve products such as neutral lipids. Antioxidant parameters revealed a limited role of O. cf. ovata to induce oxidative stress in mussels exposed under laboratory conditions excepting for a certain increase of catalase, glutathione reductase and glutathione peroxidases activities, and a significantly higher capability to neutralize peroxyl radicals in mussels exposed for 14 days. Although the obtained results suggest a non-specific response of mussels to the O. cf. ovata exposure, observed effects on the general health status of exposed mussels should be adequately considered when assessing the ecological relevance of these algal blooms.

[A new index to evaluate arterial ageing independently of arterial blood pressure: pOpscore(®)]. / Un nouvel index pour évaluer le vieillissement artériel indépendamment de la pression artérielle : pOpscore(®).

AIM: Pulse wave velocity does not correlate to age in the upper limb but in the aorta and lower limb. We studied the link between ageing and pulse wave transit time (PWtt) indexes at the toe and finger. PATIENTS AND METHODS: Measurements were performed in 300 patients in occupational medicine and primary care after 5minutes supine rest using the device studied (pOpmètre(®), Axelife SAS, France). It measures transit time between R-ECG and finger or toe pulse signal (ttf or ttt respectively). We define as follows three indexes: difference between transit times: Dtf=ttt-ttf; pulse wave velocity PWVft=k*subjects height/Dtf (m/s); and the pOpscore(®) as the ratio of toe PWV/fingerPWV. RESULTS: Of the 300 tested patients, 147 were analysed using univariate correlation: age (P<10(-4)), SBP (P<10(-4)), DBP (P<0.02) and BMI (P<0.04) correlated to Dtf, PWVtf and pOpscore(®). Using stepwise regression analysis with Age, BMI, SBP, DBP, MBP: Dtf was dependent with age (P<10(-4)) and SBP (P<0.01); PWVtf with age (P<0.0001), SBP (P<0.01) and DBP (P<0.05); pOpscore(®) was dependent only to age (P<10(-4)). CONCLUSION: In this study, in contrast with the other vascular indexes studied dependent to age and blood pressure, pOpscore(®) was dependent only to ageing. pOpmètre(®) is a promising technique for routine determination of arterial stiffness and pOpscore(®) appears to be appropriate to study the structural vascular ageing in outpatient.