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R Viviani

Publications and source records attributed to R Viviani.

At least 19 recordsLinked to original sources
PubMed2004

[A security protocol for the exchange of personal medical data via Internet: monitoring treatment and drug effects].

We present a security protocol for the exchange of medical data via the Internet, based on the type/domain model. We discuss two applications of the protocol: in a system for the exchange of data for quality assurance, and in an on-line database of adverse reactions to drug use. We state that a type/domain security protocol can successfully comply with the complex requirements for data privacy and accessibility typical of such applications.

Access to Information↗
PubMed2000

Structure determination of carboxyhomoyessotoxin, a new yessotoxin analogue isolated from adriatic mussels.

The contamination of shellfish with marine biotoxins derived from microalgae represents a serious problem for shellfish industries and public health. This study investigated the composition of diarrhetic shellfish toxins in the digestive glands of mussels from the Northern Adriatic Sea. Along with known yessotoxins, identified by comparison of their chromatographic and spectral properties with those reported in the literature, we isolated a new analogue of yessotoxin, carboxyhomoyessotoxin, whose structure was determined by mass spectrometry and (1)H NMR spectroscopy.

Animals↗
PubMed1999

Isolation of 45-hydroxyyessotoxin from mussels of the Adriatic Sea.

The diarrhetic shellfish toxin composition in the hepatopancreas of mussels from the northern Adriatic sea was investigated. The major toxins were shown to be yessotoxin (YTX), homoyessotoxin (homoYTX) and 45-hydroxyyessotoxin (45-OHYTX), identified by comparison of their chromatographic and spectral properties with those reported in the literature.

Animals↗
PubMed1997

Inhibitors of phosphoprotein phosphatases 1 and 2A cause activation of a 53 kDa protein kinase accompanying the apoptotic response of breast cancer cells.

Treatment of MCF-7 breast cancer cells with 50 nM okadaic acid triggers an apoptotic response which is accompanied by a 7-fold increase in the activity of a protein kinase with a relative molecular mass of 53 kDa. The activity of the kinase was stimulated by cell treatment with inhibitors of phosphoprotein phosphatase 1 and 2A, but not by stressing conditions. Okadaic acid-induced stimulation of the 53 kDa protein kinase was not abolished by coincubation of cells with cycloheximide. We conclude that stimulation of the 53 kDa protein kinase by inhibitors of phosphoprotein phosphatases involves pre-existing molecular components whose activity depends on the phosphorylation state of serine/threonine residues.

Calcium-Calmodulin-Dependent Protein Kinases↗
PubMed1997

Yessotoxin in mussels of the northern Adriatic Sea.

This study investigated the composition of diarrhoetic shellfish toxins in the hepatopancreas of mussels from the northern Adriatic Sea. The major toxins were shown to be yessotoxin, identified by its chromatographic properties and spectral data, and okadaic acid, detected both by fluorometric high-performance liquid chromatography and by comparison of its spectral properties with those of an authentic sample.

Animals↗
PubMed1995

ASP, DSP, NSP and PSP monitoring in 'mucilaginous aggregates' and in mussels in a coastal area of the Northern Adriatic Sea facing Emilia-Romagna in 1988, 1989 and 1991.

In this study, monitoring of marine biotoxins in "mucilaginous aggregates" and in mussels from coastal area of Emilia Romagna (Northern Adriatic Sea) in June-August 1988, 1989 and 1991, are reported. Both "mucilaginous aggregates" and mussels were analysed for NSP and PSP in 1988, and ASP, DSP, NSP, PSP in 1989, 1991. Concerning "mucilaginous aggregate" any presence of biotoxins was never detected. In the mussels it was possible to exclude the presence of PSP, ASP and NSP, but very high levels of DSP were shown in all the considered periods, in relation to the presence in the sea water of cells of the Dinophysis genus.

Adhesives↗
PubMed1992

Cadmium induction of renal and hepatic ornithine decarboxylase activity in the rat. Effects of sex hormones and involvement of the renin-angiotensin system.

We investigated the effect of sex hormones on the sex-dependent response of rat kidney ornithine decarboxylase (ODC) activity to cadmium (Cd) administration and the involvement of the renin-angiotensin system in mediating stimulation of the liver enzyme by the metal. The response of renal ODC to Cd, which occurs in intact adult males but not in females, is also detectable in prepubertal and castrated males. Upon treatment with 17 beta-estradiol, the basal levels of enzyme activity in intact or castrated adult males were enhanced and Cd administration failed to increase them further. In adult females the kidney enzyme became responsive after ovariectomy. Also, in prepubertal females renal ODC was induced by Cd, and this was prevented by treatment with 17 beta-estradiol. Under the same conditions, changes in the levels of Cd accumulation within the kidney, that might account for variations in the response of ODC activity, did not occur. Cd caused an increase in renin activity starting minutes after its injection. Captopril, which specifically inhibits the conversion of angiotensin I to angiotensin II, prevented completely the induction of liver ODC by this metal; stimulation of the enzyme by Co was not affected by the drug. A similar inhibitory effect was exerted by propranolol. Adrenalectomy had no influence on the response of hepatic ODC to Cd; the decarboxylase was unaffected by aldosterone administration. It is suggested that Cd may induce liver ODC through the increase in angiotensin II following stimulation of renin by the metal.

Age Factors↗
PubMed1992

Eutrophication, marine biotoxins, human health.

Eutrophication phenomena in marine coastal waters can today be explained on the basis of natural or anthropogenic causes. Undesirable effects and also sanitary problems in both types of eutrophication are often produced, but they may differ greatly in frequency and significance. Some algal biotoxins can affect both marine animals and man, whilst others affect man alone. From data currently available it appears that the sanitary state of man can be affected through the digestive, respiratory and cutaneous apparatus. Four main dinoflagellate biointoxications are now recognized: paralytic shellfish poisoning (PSP), neurotoxic shellfish poisoning (NSP), diarrhoetic shellfish poisoning (DSP), and venerupin poisoning. Other biointoxications are due to a diatom bloom responsible for amnesic shellfish poisoning (ASP) and to blue algae blooms which have effects on the skin and the respiratory tract. All these marine toxins are considered and particular attention is paid to: producing organisms, chemistry of the components, compromised sea foods, methods of analysis, occurrence worldwide, human intoxications, toxicology and mechanism of action on a molecular level, therapeutical notes, tolerance levels and remarks on safety. Attention is also paid to the relationship between the anthropogenic eutrophication and PSP and DSP since these are the most widespread biointoxications from toxic marine dinoflagellates in the world today and for which the European Economic Community (EEC) is proposing health legislation such as tolerance limits and methods for official analysis. In view of the harmful potential of coastal anthropogenic eutrophication, the main current committment of various countries concerns control. Finally, it is important to develop a suitable monitor research system using all the specific standards of allowed toxic substances, and also research on effective antiodotes against all biotoxins.

Animals↗
PubMed1989

Drug analysis by near-infra-red reflectance spectroscopy. Determination of the active ingredient and water content in antibiotic powders.

Near-infra-red reflectance spectroscopy is used to determine the active ingredient concentration and water content of an antibiotic powder (ceftazidime pentahydrate). The validity of predictive models for active ingredient concentrations and water content, constructed by means of the multiple linear regression technique is discussed. A procedure is devised for the analysis of production samples, which, on account of the very limited range of concentrations, prove a difficult fit to the above-mentioned model. The results obtained in testing formulation samples from 1 year's industrial production are used to illustrate the potential of the technique.

Anti-Bacterial Agents↗
PubMed1987

Polyamine distribution and activity of their biosynthetic enzymes in the European sea bass (Dicentrarchus labrax L.) compared to the rat.

1. In the liver, heart and brain of the European sea bass, putrescine concentrations are much higher than in the equivalent rat tissues; spermidine and spermine levels are smaller. 2. Ornithine decarboxylase in the bass liver is more active, but less stable than that in the rat; stability is acquired upon partial purification. Bass liver adenosylmethionine decarboxylase activity is less than that found in the rat. Both are activated and stabilized by putrescine. 4. The activating effect of putrescine decreases as the assay temperature is decreased. This may explain the high level of putrescine but low levels of spermidine and spermine in the bass liver.

Adenosylmethionine Decarboxylase↗
PubMed1985

Laser flow measurements of scattering and fluorescence from cell nuclei in the presence of increasing Mg++ concentrations.

The effects of Mg++ on the spatial organization of nuclei from rat hepatocytes are analyzed in the range 0-60 mM, in the presence of suitable concentrations of KCl to reproduce physiological conditions. It is shown that the scatter-signal distribution measured by means of a flow microfluorimeter is greatly affected by this range of Mg concentrations. By coupling this result to phase-contrast-automated image analysis, it is possible to identify a shrinking process induced by Mg++ in the range 0-2.5 mM, which reaches a plateau in the range 5-20 mM and is followed by a swelling process in the range 30-60 mM. The same Mg ranges are shown to affect the intercalation of the fluorochrome acridine orange into chromatin, suggesting that the shrinking-swelling phenomenon has also a molecular correspondence at the genome level. Possible implications in terms of the influence of Mg++ on the organization of chromatin inside intact cells are briefly discussed.

Acridine Orange↗
PubMed1984

Interaction between electromagnetic fields and cells: microelectrophoretic effect on ligands and surface receptors.

The aggregation between lectins and lymphocyte surface receptors can be affected strongly by a low-level electric field induced in the cell suspension by a time-varying magnetic field. One of the possible mechanisms is the microelectrophoretic effect due to the electric field, which influences the distance (in the mean square sense) between charged ligands and receptors when they are about to separate. On a purely theoretical basis, it is shown that, at low frequencies, an externally induced periodic electric field always decreases the mean lifetime of ligand-receptor complexes. As a consequence, the mitogenic gain obtained by lectin addition to cell suspension is decreased. These results suggest that such a mechanism, if effective, reduces the lectin mitogenic capability and offers a way of handling similar phenomena which have been described for other biological systems.

Electromagnetic Fields↗
PubMed1982

Early effects of chemical carcinogens as compared to induced cell proliferation. II. Automated image analysis.

Static automated image analysis was applied to study early variations of chromatin structure in Feulgen-stained liver nuclei from rats injected i.p. with a single dose of dimethylnitrosamine (DMNA), a well known hepatocarcinogen. An increase of nuclear area and a correspondent decrease of average optical density (integrated optical density/area) was observed, as compared with controls, in nuclei from rats treated with 5.4 mg/kg of DMNA. These findings, which were comparable with those induced by partial hepatectomy, indicate the existence in DMNA-treated cells of a chromatin DNA relaxation similar to the G0-G1 transition previously described for human diploid fibroblasts stimulated to proliferate. Because similar results were independently obtained by flow microfluorimetry, it seems reasonable to hypothesize that chromatin decondensation could be a prerequisite for cancer induction.

Animals↗
PubMed1982

Early effects of chemical carcinogens as compared to induced cell proliferation. I. Flow microfluorimetry.

Acridine orange-stained rat liver cells have been analyzed by flow microfluorimetry either after i.p. injection of 0.6 and 5.4 mg/kg of dimethylnitrosamine or 18 hr after partial hepatectomy. Treatment with dimethylnitrosamine induced a marked increase in the fraction of cells with higher green fluorescence intensity which can be related to a greater number of chromatin primary binding sites, and a decrease in the fraction of cells with higher red fluorescence intensity corresponding to a lower amount of cellular RNA. Contrary to the carcinogen-induced early changes towards a more relaxed uncoiled structure, as well as an apparent uncoupling between chromatin-DNA structural alterations and total RNA synthesis, could be first events in the carcinogenetic process.

Acridine Orange↗
PubMed1981

[Staining with naphthol yellow S. 2. Study of the reversibility of the protein-dye binding reaction].

In the present work we studied the reversibility of the binding reaction of Naphthol Yellow S to proteins using a Testing Automatic System Leitz. We presently think that the NY-S staining procedure, can be used as a reliable quantitative method for the determination of nuclear and cytoplasmic proteins only under standardized conditions: the ratio R = [Dye-] / [R-NH+3] must be more greater than 10; for staining periods shorter than 45 min, the slides, at equilibrium, must be mounted in dyeing solution; for quantitative determinations using irreversible bound dye, the staining period must be significantly longer than 45 min (see above) and differentiated in running water for several hours.

Animals↗