Sedimentation fluxes of major nutrients are investigated during 1996 and 1997 at three different depths and two locations in eutrophic southern basin of Lake Lugano (Switzerland). Horizontal ...differences between the two sites are on the order of 10-40% (but can exceed 50%), whereas differences related to interannual oscillations range between 5 and 24%. Particulate organic carbon (POC) and nitrogen (PN) fluxes show a constant increase of 5-20% from the upper to the bottom trap. This tendency remains more or less constant during the year. On the contrary, particulate phosphorus (PP) shows a seasonal variation, with higher accumulation rates from the I to the III trap in autumn and winter which can exceed +1200%. This phenomenon is due to the interaction between the dissolved phosphorus (DP) and the iron(oxi)hydroxides (Fe(OH)3) near the oxycline. Fe(OH)3 precipitates at the iron redox boundary, scavenging DP. This enrichment flux increases together with the development of the anoxic benthic layer. The efficiency of the iron redox layer in trapping upward diffusing P is related to the concentration of dissolved iron in the anoxic hypolimnion. In Lake Lugano the two considered sites present major difference of iron concentration, and this difference is reflected in the P sedimentation fluxes. The exposition of an additional sedimentation trap above the maximal oxycline height has allowed to gain insight into this phenomenon.
Eight high mountain lakes located above 2000 m a.s.l. in the watershed of Lago Maggiore, with alkalinity between 10 and 100 μeq l-1, were studied during summer 1997. The survey revealed that some of ...the lakes had a saline density gradient which might hinder the mixing of water and restrict the oxygenation in hypolimnion. Following acidification, aluminium was present in some lakes in the form of Al(OH)2 +, with pH around 5.9, and as Al(OH)4 -, with pH around 6.6. The negative correlation observed between pH and nitrate concentrations seems to be linked to vegetal activity. In fact, acidity in soil and water, combined with the presence of aluminium, can partially inhibit the metabolism of plants and algae, and reduce the assimilation of NO3 -. Major biological differences emerged among the lakes, both at the level of plankton composition and biomass, and in seasonal dynamics. Dinophyceans and chlorophyceans predominated quantitatively in the lakes with low pH and alkalinity values, whereas diatoms were present in the lakes with higher values of these parameters. The phytoplankton biodiversity index showed a considerable variation from lake to lake. Higher alkalinity and salinity was not coupled to a higher biocenosis diversity and one or two species tend to dominate the others.
The pelagic populations in Laghetto Inferiore (southern Swiss Alps) were studied between 1996 and 1998 during the ice-free period. Investigations revealed a considerable number of phytoplankton ...species but few zooplankton species. The vertical distribution of the main species of algae shows a marked vertical stratification, with higher biomass concentrations in the deep zone. Along this profile, species in the same taxonomic class tend to be distributed at different depths, according to their specific light requirements. During the study period no clear seasonal succession of populations was observed, also because of the influence of precipitation on the biological cycles. On the whole there was a good correspondence between the biomass values of phytoplankton and those of chlorophyll-a, both in integral samples of the whole water column and in the vertical profile.
The antiproliferative effects mediated by a 14-mer homopyrimidine oligonucleotide (5' CTTTCT-CTTTTCTC3'), designed to form DNA triplex with a purine region of the DNA polymerase alpha promoter, were ...evaluated on the human breast cancer cell line MDA-MB 231. In order to stabilize the triple complex under physiologic conditions, replacement of cytosines by methylcytosines in the oligomer sequence was carried out. Band-shift analyses demonstrated a complete triplex formation between the radiolabeled target duplex DNA and the methylcytosine-modified oligomer at the concentration of 0.1 microM under physiologic pH and temperature. A single exposure of MDA-MB 231 cells to 0.5 microM methylcytosine-modified oligonucleotide was able to markedly reduce the cell number and the percentage of cells in DNA synthesis up to 58% and 66%, respectively, compared with controls. Furthermore, a 48% reduction in the amount of the DNA polymerase alpha mRNA was reported after treatment with the oligomer. In conclusion, data from the present study demonstrate that an oligonucleotide to DNA polymerase alpha promoter, designed to form a triple helix with target double-stranded DNA, inhibits the expression of the reporter gene at the biologic and molecular levels, suggesting a possible triplex-mediated mechanism of action.
LUNAM 2000 is a small mission dedicated to the coronagraphic imagingin the Na yellow doublet and to UV spectroscopy in the range2800–3400 Å of the lunar atmosphere. These studies are possible only ...from Space. The scientific return of LUNAM 2000 has a wider appeal for the studyof transient atmospheres of other celestial bodies, in particular ofMercury. The mission is in low Earth-orbit (about 350 km); asun-synchronous or other orbits are under investigation. The payload has very small weight, dimensions and power requests, and is essentially made withoff-the-shelf components. It can be built and launched in less than 3years from the approval. This time frame nicely overlaps that of theEuropean technological Mission SMART 1 and can greatly add to itsscientific return. Furthermore, LUNAM 2000 can give very importantinformation to define a mission to Mercury such as Bepi Colombo.
Ninety-six patients with pathological stage IIIs Hodgkin's disease, uniformly treated with six cycles of MOPP and TNI, were retrospectively analysed in an effort to determine whether the ...lymphographic aspect of lymph nodes influence the prognosis. Case material was grouped according to the presence of lymph nodes less than 3 cm in diameter or larger at lymphography. Five-year survival and disease-free survival were 85 and 78% for patients with small lymph node involvement, compared to 48 and 30% for patients with larger lymph nodes. The comparative analysis between the lymphographic aspect and other prognostic factors shows that large lymphographic involvement is strongly correlated with the presence of large spleen involvement (P less than 0.0000029), followed by stage III2 (P less than 0.000612), followed by greater than or equal to 5 involved sites (P less than 0.012), followed by age greater than 40 yr (P less than 0.047). Conversely, no significant correlation was found with symptoms, histology and mediastinal involvement. Modifications of current treatment for both large and small lymph node involvement are discussed.
Five hundred and seven patients with Hodgkin's lymphoma (HL), forming the basis of our 18 years experience, are retrospectively analyzed. Four therapeutic periods are recognizable: The 1966-1970 ...period was characterized by the absence of treatment and management policy. The 55 patients entered in this period experienced 70 and 56% survival at 5 and 10 yr, respectively, from diagnosis. The 1971-1974 period was characterized by the increasing knowledge of staging relevance and therapeutic approaches. The 153 patients who were treated in this period experienced 72 and 60% survival at 5 and 10 yr, respectively. The 1975-1980 period was characterized by a large combination of MOPP and radiotherapy. The 216 patients who entered this period observed 80 and 72.5% survival at 5 and 10 yr, respectively. The last therapeutic period (1980 to present time) is characterized by the increasing relevance of prognostic factors and alternating use of MOPP and ABVD as non-cross resistant regimen. The 83 patients who entered this period showed 90% survival at 5 yr. Both survival and disease-free survival were positively influenced by the change of therapeutic strategies during the four periods (P less than 0.005). Although better results have been recorded moving from one to the next therapeutic period, the present policy has been also based on the recognition of a high number of late complications due to the therapy. Preliminary results about the present therapeutic experience seem to indicate both a good remission rate and low incidence of complications.
