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Immunotoxicity of butyltins in Tunicates.
No full textButyltins, widely used as biocides mainly in antifouling paints and wood preservatives, cause deleterious effects on marine ecosystems, particularly on filtering invertebrates such as bivalve molluscs and tunicates. Colonial ascidians are reported to be very sensitive to butyltins so that mortality occurs after exposure at concentrations higher than 100 ng/L. Besides, di- and tributyltins have been shown to interfere with immune system of mammals, causing atrophy of the thymus and lymphoid tissues, and cytolysis of PMNs after inhibition of chemotaxis and respiratory burst, with resultant depression of cell mediated immune responses.
We studied the in vitro effects of tributyltin (TBT), dibutyltin (DBT) and monobutyltin (MBT), respectively as mono-, di- and trichloride, on the yeast phagocytosis by hemocytes of the colonial ascidian Botryllus schlosseri. A highly significant decrease of hemocyte viability (trypan blue test) was observed following an 1 hr exposure at concentrations higher than 100 μM for DBT and TBT, and 1 mM for MBT. Then the phagocytosis test was performed with the three compounds at 0.1, 1, 10 μM. The phagocytosis index was significantly reduced in the following order: DBT (1 μM), TBT (1 – 10 μM) and MBT (10 μM). The same order of inhibition was observed for Ca2+_ATPase activity. These results suggest that the inhibition of phagocytosis may be linked strictly with inhibition of Ca2+-ATase. TBT effects were thus compared with those induced by ouabain, as reference enzyme inhibitor, at a non lethal concentration (10 mM). A combined response of summation or additive effect of TBT and ouabain was demonstrated by means of cross-experiments with isodynamic mixtures, suggesting a common mechanism of action. These results were confirmed by cytochemistry of Ca2+, since the accumulation of the ion was directly proportional to inhibition of Ca2+-ATPase. Some morphological changes occurred, but without cytolysis. All these results suggest that the organotins interact with calcium pump, probably through calcium channels and calmodulin as demonstrated in mammals. As TBT is also known to inhibit mitochondrial oxidative phosphorylation, 2,4 dinitrophenol (DNP) was tested as reference enzyme inhibitor at a sublethal concentration (0.1 mM). A combined response of incomplete summation or less than additive effect was demonstrated by means f cross-experiments with isodynamic mixtures of TBT and DNP, suggesting a secondary and/or indirect mechanism of action
IL RISCHIO IN ITALIA DA SOSTANZE INORGANICHE. FONDO NATURALE CONTAMINATO E INCONTAMINATO.
No full textQuesto documento rappresenta il primo e per ora unico tentativo in Italia di raccogliere tutti i dati disponibili in letteratura circa le concentrazioni di 39 elementi e relativi composti inorganici di significato tossicologico presenti nel nostro Paese nei vari comparti del fondo naturale, rappresentati da aria (gas atmosferici, emissioni vulcaniche), acqua (sorgenti minerali, fiumi, laghi, mari), suolo (giacimenti minerari), organismi vegetali e animali di zone sia incontaminate che contaminate dalle attività produttive umane. Tale sforzo interdisciplinare tra Scienze Naturali e Tossicologia Medica e Ambientale, promosso da una fruttuosa collaborazione tra l'ANPA e l'Università degli Studi di Padova, è stato considerevole per la scarsezza, la disomogeneità, la frammentarietà e l'incompletezza dei dati di monitoraggio del fondo naturale per tutte le regioni d'Italia da imputare al mancato completamento, a partire dagli anni Ottanta della nuova Carta Geologica d'Italia e della Carta Pedologica d'Italia, nonché alla cessazione, dal 1985, delle relazioni del Corpo delle Miniere, ripercuotendosi poi nei dati produttivi alquanto generici riportati nei più recenti Annuari ISTAT. Lo studio del fondo naturale delle sostanze pericolose inorganiche nel nostro Paese costituisce la premessa indispensabile per una valutazione d'impatto ambientale scientificamente strutturata, attendibile e fondata sulla conoscenza pregressa delle proprietà chimiche, fisico-chimiche, biologiche e tossicologiche di tali sostanze sui carichi naturali, delle modalità di immissione e dei meccanismi del loro trasporto, così da individuare sia le sostanze più pericolose per la salute umana e per l'ambiente sia le aree critiche o a rischio. Questo documento diventa pertanto uno strumento indispensabile per il naturalista specializzato in progetti VIA nel nostro Paese, poiché offre gli elementi conoscitivi necessari per prospettare ed impostare un sistema di controllo a partire da studi e ricerche finora effettuati e in comparazione con quelli disponibili in altri paesi confrontandoli con i limiti di accettabilità definiti dalle diverse normative. E' possibile inoltre stabilire quali siano gli elementi più probabilmente responsabili dell'inquinamento ambientale, le loro variazioni nel tempo, tenendo conto del trasferimento dai compartimenti abiotici e delle trasformazioni biologiche che li rendono più biodisponibili e quindi più tossici
Tossicomanie rare I: da inalazione di vapori, con riferimento ad un caso di dipendenza da vapori di benzina
No full textToxicity of organotin compounds on embryos of a marine invertebrate (Styela plicata; Tunicata)
Full text linkOrganotin compounds are an useful class of tin chemicals, a number of which have found commercial applications and are industrially synthesized in large amounts. Their uncontrolled use may cause profound effects on the fate and long-term environmental impact in natural aquatic environments. Butyltin compounds (TBT and its degradation products, i.e. DBT and MBT) are leached out from antifouling paints; triphenyltin (TPT) and tricyclohexyltin (TCHT) compounds have source in the run off waters of treated plants on which they are use as pesticides. There is much concern about their hurtful effects on marine life, especially fish and molluscs. The lagoon of Venice is a particular coastal area with shallow and incompletely turnovering waters, in which the resident benthonic population suffers the negative impact of organotins for bioaccumulation. In order to clarify the interaction mechanism, we studied the toxic effects of organotins on a benthonic filter-feeding ascidian. We followed the embryonic development of the ascidian Styela plicata with two different approaches: i) in vivo observations on different stages of ascidian development from fertilized egg to larval stages by incubation with 0.1, 1, 10 μM organotins for various exposure times; ii) ultrastructural observations on the early embryonic stages (2-4 cells, morula, gastrula) incubated with 10 μM TBT or TPT for 1 hour. Our results show that organotins significantly affect all stages of ascidian development in a dose- and time-dependent manner and the most sensitive stages are gastrula and neurula. These compounds are able to block the development giving rise to anomalous embryos with irreversible effects. The order of inhibition appears strongly dependent on the organotin liposolubility: TBT>DBT>MBT and TPT>TCHT. The mitosis block of blastomers in the early stages may be related to an inhibition of the microtubule polymerization. Observations with light and electron microscopes reveal globe-shaped blastomers with large intercellular spaces in morula and gastrula stages, suggesting a toxic damage on aggregation of microfilaments. Moreover the occurrence of electron-dense precipitates of organotins in the inner membrane of mitochondria and morphological changes of their cristae suggests an inhibition of mitochondrial oxidative phosphorylation which is important in the gastrula stage. In this stage, these electron-dense aggregates grow from 50-70 nm to 110-170 nm and the alteration of the cristae increases
PCBS AND ORGANOCHLORINATED PESTICIDES IN EELS (ANGUILLA ANGUILLA L.) FROM THE PO DELTA.
No full textEels (Anguilla anguilla L.) live in the brackish waters vallis of the Mediterranean, where the elvers enter the lagoons and estuaries and grow in the sheltered areas, feeding on natural food available in the bottom sediments. Eels are therefore exposed to persistent pollutants, such as polychlorinated biphenyls (PCBs) and organochlorine pesticides. These lipophilic xenobiotics tend to accumulate in high concentrations in this species because of its considerable fat amount. Alarming concentrations form heavily polluted areas have been reported in eels; for example, 91% of this species of fish from the lower Elbe River contained levels exceeding the regulatory limits. Moreover, studies from the river Rhine have suggested that the high levels of organochlorine residues found in eels, are due to biomagnification through the food chain. PCBs and chlorinated pesticides have also been detected in different species of fish in the final stretch of the River Po, which is considered a land based source of pollution in the Adriatic Sea. In order to find out whether contamination by PCBs and organochlorine pesticides in the Po Delta poses a risk to human and animal health, studies on the content of the above pollutants in eels were carried out. Twenty eels of 548 +- 126 g weight and 43 +- cm length, were caught twice a year, in March and October 1994. Fish muscles were homogenized in a mixer and freeze-dried. A 30 g sample of the above mixture was dissolved in 20 ml of acetonitrile and placed in an ultrasonic bath for 5 minutes. After sedimentation the supernatant was centrifuged at 1400 rpm for 10 minutes, following which the volume was reduced by means of a rotavapor to about 5 ml and the resulting extract passed through a liquid chromatography LC-18 (octadecyl) column in order to remove lipids and hydrocarbons. Subsequently, this extract was passed through a LC-NH2 (aminopropil) column to remove polar substances such as amines and organic acids and then it was further concentrated under a gentle stream of N2 at room temperature. A gas chromatography-mass spectrometry (Hewlett Packard 5890 GC with a 5989 mass selective detector) equipped with a fused silica capillary column (Alltech SE 30 m x 0.25 mm) was used for the quantification of the pesticides. The operating conditions were as follows: injection port temperature 260 °C, column initial temperature 100 °C, rate of temperature increase 10 °C/min. With a final temperature of 300 °C, helium was used as the carrier gas (25 cm/sec at 200 °C). The mass spectrometer was used in SIM mode (Selected Ion Monitoring) under the following conditions: electron energy 70 eV, source temperature 200 °C, quadrupole temperature 100 °C, electron multiplier voltage 2200 V. The SIM programmes used for the analysis of chlorinated pesticides and PCBs were selected to enable the simultaneous determination of more than fifty compounds. Confirmation and quantification of the various pesticides and PCBs, were carried out by comparison with standard of 99-100% purity (Cambridge Isotope Lab., Woburn, MA, USA). The levels of pollutants found in fish muscle demonstrate the continuing presence of p,p’-DDT (4.16 +- 0.76 μg/kg dry weight) and some metabolites (p,p’-DDE and p,p’-DDD) although it has been banned in Italy since 1978. Contamination with other organochlorinated pesticides was significant, whereas for PCBs high values were found (23.80 +- 8.15 μg/kg dry weight). However, this levels do not present risk for the survival and normal development of fish living in this area. Therefore, there is no real health hazard for people consuming eels caught in waterways form the River Po
PCBS AND ORGANOCHLORINATED PESTICIDES IN EEL (ANGUILLA ANGUILLA L.) FROM THE PO DELTA.
No full textPolychlorinated biphenyls (PCBs) and organochlorinated pesticides were extracted from samples of muscle from eel (Anguilla anguilla L.) caught in the Po Delta and determined by fused silica capillary gas chromatography/mass spectrometry (GC/MS). The main compound identified were polychlorinated biphenyls, HCB, p,p’-DDT and its metabolites, p,p’-DDE and p,p’-DDD. PCB and DDT concentrations were higher in eel captured in spring than in those fished in autumn and were correlated with fat concentrations in muscle tissue. Mean PCB levels were 265 +- 9 and 211 +- 6.9 microg/kg wet weight, and those of DDT compounds 18.45 +- 12.7 and 15.76 +- 10.6 microg/kg wet weight, respectively. They were also higher than those determined in other species of fish captured in the same body of water, although the data indicate that there is probably no real health risk from irregular consumption of eel containing these xenobiotic concentrations
A double-blind study of fluoxetine and imipramine in major depression
No full textEighteen outpatients with major depression (diagnosis was made according to DSM-III criteria) were treated in a 5-week double-blind parallel group comparison of the new antidepressant fluoxetine with imipramine. From these results it can be shown that the drugs were comparable in efficacy, although because of the small sample size a moderate clinical difference between treatments may not have been detected. Imipramine and fluoxetine have already been compared in other studies, but never at such a low dosage (20 mg) for fluoxetine. At this dosage the fluoxetine safety profile seems to be very different from previous scheduled studies with higher dosages. In fact clinical efficacy seems to remain comparable while side-effects are significantly less frequent
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