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There is a wide range of research projects carried out within our Department of Biomedical Sciences about the environmental consequences caused by toxic heavy metals: we have demonstrated by in vitro experiments that cadmium can induce ultrastructural alterations, with different degree, in the structure of human fetal liver. The goal of this study was to develop our research testing in vivo in experimental animal model the results obtained.

Because of its high rates of soil-to-planttransfer, Cd is a contaminant found in most human foodstuffs, which renders diet a primary source of exposure among nonsmoking, non-occupationally exposed populations. A safe intake limit of 7 μg cadmium/week/kg body weight was set based on the critical renal cadmium concentration of between 100 and 200 μg/g wet weight. The aim of our research was to study Cd effects on morphology of the glomerular and tubular cells of kidney in experimental animal.

This work aims at presenting an analysis of the evolution of the physical properties of a water column at the southern limit of the Ross Sea, Antarctica. Data has been collected over a four year period (from January 1995 to July 1998) by means of an oceanographic mooring (named mooring “F”) berthed a few miles north of the Ross Ice Shelf at a depth of 600 m on the continental shelf. The velocity and temperature measurements have been investigated seeking for ISW (Ice Shelf Water) outflow footprints. These outflows are irregular massive injections of cold water from below the Ice Shelf, flowing mainly across the cavity floor into the Ross Sea bottom layers. The study evidenced a large number of DISW outflow events (Deep Ice Shelf Water, the coldest and densest fraction of the ISW, the actual main object of the present study), characterized by an interannual variability that could turn out to bean important co-factor in the variations of the planetary heat balance and climate instability. Differences in DISW outflow timings from biennium 1995-1996, during which a jet-like behaviour was dominating (each events was only a few days long), and 1997-1998 (with a few long and rather continuous cold water outflows) have been detected. Moreover, in 1996 measurements evidenced a relatively long and warm period (about 110 days from March to July) characterized by the total absence of DISW outflow, this interval being more than twice longer with respect to any other similar ones registered during 1995, 1997 and 1998, and longer that any other warm period observed in the area during the early ’80s. The estimates of cold water exchanged during the four years return a more complicated framework: 1996 behaviour seems to be closer to the 1997 than to the 1995 one, with high fluxes and high volumes. 1995 can probably be considered as the ignition of an interannual anomaly, which climax is the long warm period of spring 1996.

This study addresses the feasiblity of Ocean Acoustic Tomography for long-term monitoring of polynyas. OAT applicability has been investigated by means of the available observations in Terra Nova Bay polynya (Ross Sea, Antarctica) and by simulations with a range dependent, multi-layered adiabatic normal-mode acoustic propagation model. The summer sound speed profile is characterised by surface values around 1450 m/s, a minimum of 1441 m/s around 50 m depth and a linear increase with depth up to 1453 m/s at the bottom, thus leading to ducted propagation in the near surface layer and upward refraction below, while during winter, due to water cooling and mixing process, the subsurface minimum disappears and surface sound speed is about 1440 m/s. The feasibility study of acoustic inversion was approached by means of normal mode Match Field Tomography and the results from simulations demonstrate that ocean acoustic tomography is able to reproduce quite well the vertical sound speed profile, in particular the temporal evolution of summer stratification and winter mixing processes, thus providing information on the upper layer, where direct measurements are not possible.

The aims of the Aegean Hydrothermal Fluxes and Biological Production project were to estimate the fluxes of fluids, chemicals, heat and bacteria from hydrothermal vents, establish the controls on venting dynamics, measure the productivity in the region of the vents and establish the effect of the vents on biodiversity of both prokaryotes and eukaryotes. This paper presents an initial synthesis of the project results. Research was done both by land-based SCUBA diving and from several vessels at a number of active sites in the near-shore coastal regions of Milos and Kos, with some additional studies at Methana, Lesbos and Santorini. Vent water composition showed very large variations. This was due to the mixing, of hydrothermal reservoir fluids, vapour condensate and seawater altered by interactions of fluid-sediment-bacteria in different proportions, in the gasohydrothermal vents. The composition ranged from nearly sea water with only slightly reduced pH, to higher or lower salinity fluids with a pH as low as 3 and with large enrichments in heavy and trace metals. Phase separation was a common feature at these shallow vents. The dry gas phase was mainly CO2, but with significant amounts of H2S, CH4 and H2. These fluids commonly passed through soft sediments before venting from the seafloor and induced a convection cell of pore-water entrainment from deeper sediment layers into the water column with a consequent 're-charge' down-flow of seawater into the sediment around the vent outlets. Such complex conditions may well explain the high biodiversity of Bacteria, Archaea and epifaunal species surrounding the vents. As many as 44 % of the archaeal lineages detected were found to represent novel phyla. Epifaunal diversity was particularly high with over 200 species recorded at the shallower Milos vents. These vents may form a 'stepping-stone' for warmer water species to colonise the surrounding areas when water temperatures permit.

We investigated the frequency of a rare variant of a common microsatellite tetrarepeat allele in the tyrosine hydroxylase gene in 2 independent ethnic groups of schizophrenic patients and their matched controls. In a French population we found the rare variant allele in 5 of 94 (5%) unrelated chronic schizophrenic patients and in none of 145 unaffected controls, thus yielding a significant association (p0.01) between schizophrenia and the tyrosine hydroxylase gene. Similarly, in a replication study, we found the rare allele in 4 of 44 (9%) unrelated chronic schizophrenic patients and in none of 44 unaffected controls in a Tunisian population. Albeit the reason of this association is at the moment unknown, it is possible that this polymorphism in the tyrosine hydroxylase gene may be involved in the regulation of its activity.

Deze eerste door de B.I.L. georganiseerde uitstap naar België was een groot succes. Op het programma stonden een bezoek aan de Duvel-brouwerijen, een uitgebreide voorlichtingsdag bij het hoofdkwartier van de N.A.V.O. en de excursie werd afgesloten met een ontmoeting met de burgemeester van Antwerpen in het aloude stadhuis