968 resultados para Anas acuta
Resumo:
La presenza di residui dei farmaci ad uso umano e veterinario nelle acque superficiali è in costante aumento a causa del loro elevato consumo. L’impatto ambientale dei prodotti farmaceutici è riconosciuto in tutto il mondo ma attualmente ancora non sono presenti degli Standard di qualità ambientale per queste sostanze in ambiente acquatico. L’agenzia europea per i farmaci (EMEA) ha introdotto delle linee guida per la valutazione del rischio ambientale per tutti i nuovi farmaci prima di provvedere alla registrazione, ma in nessun caso la loro autorizzazione in commercio è vietata. Una volta assunti, i farmaci sono escreti dagli organismi in forma nativa o come metaboliti, e attraverso gli scarichi urbani raggiungono i depuratori che li rimuovono solo in parte. Di conseguenza, i residui dei farmaci vengono ritrovati nei fiumi, nei laghi, fino alle acque marine costiere. Anche se presenti a basse concentrazioni (ng-μg/L) nelle acque superficiali, i farmaci possono provocare effetti avversi negli organismi acquatici. Queste specie rappresentano involontari bersagli. Tuttavia molti di essi possiedono molecole target simili a quelle dell’uomo, con i quali i farmaci interagiscono per indurre gli effetti terapeutici; in questo caso i farmaci ambientali possono causare effetti specifici ma indesiderati sulla fisiologia degli animali acquatici. Le interazioni possono essere anche non specifiche perché dovute agli effetti collaterali dei farmaci, ad esempio effetti ossidativi, con potenziali conseguenze negative su vertebrati ed invertebrati. In questo lavoro sono stati valutati i potenziali effetti indotti nelle larve di orata da quattro classi di farmaci ovvero: carbamazepina (antiepilettico), ibuprofene (antinfiammatorio non steroideo), caffeina (stimolante) e novobiocina (antibiotico). In particolare, in questo lavoro si è valutato inizialmente il tasso di sopravvivenza delle larve di orata esposte ai farmaci, per verificare se l’esposizione determinasse effetti di tossicità acuta; successivamente si è passati alla valutazione di due biomarker : il danno al DNA e la perossidazione lipidica per verificare la presenza di effetti tossici sub-letali. Le larve sono state esposte per 96 ore alle concentrazioni di 0.1, 1 (MEC), 10 e 50 µg/L (>MEC) di carbamazepina e novobiocina, a 0.1, 5 (MEC),10 e 50 µg/L (> MEC) di ibuprofene ed a 0.1, 5 (MEC),15 e 50 µg/L (> MEC) di caffeina, rappresentative delle concentrazioni riscontrate in ambiente acquatico e al di sopra di quest’ultimo. L’analisi dei dati sulla sopravvivenza ha dimostrato che la carbamazepina, l’ibuprofene, la novobiocina e la caffeina non hanno effetti significativi alle concentrazioni testate. La valutazione dei biomarker ha evidenziato un generale decremento significativo dei livelli di danno primario al DNA e per la perossidazione lipidica è stato generalmente osservato un decremento alle dosi dei farmaci più basse, seguito da un aumento a quelle più elevate. Nell’insieme i dati indicano che alle concentrazioni testate, i farmaci carbamazepina, caffeina, ibuprofene e novobiocina non hanno prodotto alterazioni attribuibili alla comparsa di effetti avversi nelle larve di S. aurata dopo 96 ore di esposizione.
Resumo:
La tesi inizia indagando il trend degli incidenti con fuoriuscita stradale avvenuti negli ultimi dieci anni andando in seguito a verificare uno dei molteplici aspetti che caratterizzano le barriere di sicurezza, dispositivi installati al fine di ridurre gli effetti delle fuoriuscite. In particolare ci si e concentrati sulla variazione della lunghezza di infissione del montante delle barriere che in terreni differenti da quelli in cui si eseguono i crash-test possono dare risultati risultati differenti in termini di deformazioni della barriera in caso di urto.
Resumo:
The detection of autoantibodies is an important cornerstone in the diagnosis of systemic autoimmune disorders such as autoimmune connectivitides and small vessel vasculitides. Antinuclear antibodies (ANAs ) and antineutrophil cytoplasmic antibodies (c+p-ANCAs) are appropriate diagnostic screening tools for autoimmune connectivitides and small vessel vasculitides. For economic and intellectual/didactic reasons more extensive autoantibody diagnostics should be performed only in particular situations when patients history and clinical exam lead to strong diagnostic suspicion.
Resumo:
OBJECTIVES: To characterize Tn6198, a novel conjugative transposon from the clinical Listeria monocytogenes strain TTH-2007, which contains the tetracycline and trimethoprim resistance genes tet(M) and dfrG, respectively, and to assess its transferability in vitro and in situ. METHODS: The complete sequence of Tn6198 was determined using a primer walking strategy. Horizontal gene transfer studies were performed by filter matings, as well as on the surface of smear-ripened cheese and smoked salmon. The presence of Tn916-like circular intermediates was determined by PCR. Antibiotic resistance was determined by the broth microdilution method and microarray hybridization. RESULTS: Sequencing of Tn6198 revealed that a 3.3 kb fragment containing dfrG was integrated between open reading frames 23 and 24 of Tn916. Furthermore, an additional copy of Tn916 was present in L. monocytogenes TTH-2007. Both elements were transferred simultaneously and separately in vitro to recipients L. monocytogenes 10403S and Enterococcus faecalis JH2-2 by conjugation, resulting in either tetracycline- and trimethoprim-resistant or solely tetracycline-resistant transconjugants. On the surface of cheese and salmon, only L. monocytogenes 10403S transconjugants were detected. CONCLUSIONS: This study reports the first Tn916-like element associated with a trimethoprim resistance gene, as well as the first fully characterized transposon conferring multidrug resistance in L. monocytogenes. This is of concern, as trimethoprim is administered to listeriosis patients with β-lactam allergy and as Tn6198 has a large potential for dissemination, indicated by both intra-species and inter-genus transfer.
Resumo:
Expression of the K1 gene of human herpesvirus 8 activates nuclear factor-kappaB and induces lymph node hyperplasia and lymphomas in transgenic mice. To further delineate its role in cell survival, we determined whether K1 altered apoptosis of lymphoma cells. K1 protein is expressed in Kaposi sarcoma and primary effusion lymphoma. We retrovirally transfected BJAB lymphoma, THP-1, U937, and Kaposi sarcoma SLK cells to express K1 and a K1 mutant with the deleted immunoreceptor tyrosine-based activation motif (K1m). We challenged cells with an agonistic anti-Fas antibody, Fas ligand, irradiation, and tumor necrosis factor-related apoptosis-inducing ligand. K1 transfectants but not K1m transfectants exhibited reduced levels of apoptosis induced by the anti-Fas antibody but not apoptosis induced by the tumor necrosis factor-related apoptosis-inducing ligand or irradiation. K1 expression resulted in reduced apoptosis rates as shown in several assays. K1 induced a modest reduction in levels of Fas-associated death domain protein, and procaspase 8 recruited to the death-inducing signaling complex. Finally, K1 transfectants cleaved procaspase 8 at significantly lower rates than did K1m transfectants. K1-transfected mice, compared with vector-transfected mice, showed lower death rates after challenge with anti-Fas antibody. K1 may contribute to lymphoma development by stimulating cell survival by selectively blocking Fas-mediated apoptosis.
Resumo:
PURPOSE Thoracoscopic sympathetic surgery is nowadays a broadly accepted technique in the treatment of primary hyperhidrosis as well as facial blushing. The objective of this study was to compare the two currently most commonly used methods for thoracic sympathicotomy: transection (ETS) and clipping (ETC.). METHODS This is a retrospective study on a total of 63 patients, who underwent rib-oriented sympathicotomy, either by transection (n = 36, 57 %) or by clipping (n = 27, 43 %). Moreover, the up-to-date international literature is reviewed concerning which level(s) of the sympathetic trunk should be addressed, depending on the patients underlying condition. Furthermore, the highly controversial topic of reversibility of sympathetic clipping is debated. RESULTS Our results confirm that clipping is at least as effective as transection of the sympathetic chain in the treatment of hyperhidrosis and facial blushing. Furthermore, the analysis of all larger studies on unclipping in humans shows a surprisingly high reported reversal rate between 48 and 77 %. CONCLUSIONS Depending on the symptoms of the patient, different levels of the sympathetic chain should be addressed. When a higher rib level such as R2 is approached, which more likely will result in moderate to severe compensatory sweating, clipping should be preferred as it seems that this technique has indeed a potential for reversibility. As demonstrated, this method is at least as effective as an irreversible transection of the sympathetic chain.
Resumo:
BACKGROUND Maculopapular or urticarial eruptions and erythema multiforme sometimes occur in patients affected with Mycoplasma pneumoniae respiratory infections. Further eruptions have also been reported. OBJECTIVE To review the literature addressing M. pneumoniae respiratory infection and rather unusual eruptions. METHODS Computer-based search in the U.S. National Library of Medicine database as well as in the search engine Google. RESULTS We found a possible relationship between M. pneumoniae infection and Fuchs' syndrome (n = 37), varicella-like eruptions (n = 8), Henoch-Schönlein syndrome and further leukocytoclastic vasculitides (n = 21) and erythema nodosum (n = 11). A temporal relationship was also observed with 2 cases of Gianotti-Crosti syndrome. Finally, there exists reasonable evidence that pityriasis rosea Gibert and pityriasis lichenoides et varioliformis acuta Mucha-Habermann are not associated with Mycoplasma infections. CONCLUSION This review implies that M. pneumoniae may cause, in addition to erythematous maculopapular (or urticarial) eruptions and erythema multiforme, Fuchs' syndrome and varicella-like eruptions. Furthermore, there is an intriguing link with leukocytoclastic vasculitides or erythema nodosum that deserves further investigation.
Resumo:
Benthic foraminifers of the Coniacian-Santonian through the Paleocene were recovered from a continuous pelagic carbonate section from Hole 516F on the Rio Grande Rise. Sixty-five genera and 153 species have been identified, most of which have been reported from other localities. Bathyal depths are reflected in the benthic assemblages dominated by gavelinellids (Gavelinella beccariiformis, G. velascoensis), Nuttallides truempyi, and various gyroidinids and buliminids. Rapid subsidence during the Coniacian-Santonian from nearshore to upper to middle bathyal depths was followed by much reduced subsidence, with the Campanian-Paleocene interval accumulating at middle bathyal to lower bathyal depths. A census study based on detailed sampling reveals major changes in benthic faunal composition at the Cretaceous/Tertiary boundary transition. It was a time of rapid turnover, with the extinctions of numerous species and the introduction of many new species. Overall, species diversity decreases about 20%, and approximately one-third of latest Maestrichtian species do not survive to the end of the Cretaceous. This shift indicates a significant environmental change in the deep sea, the precise nature of which is not apparent from the foraminifers or their enclosing sediments.
Resumo:
Cenozoic planktonic foraminiferal biostratigraphy at DSDP-IPOD Leg 80 sites documents the existence of regionwide stratigraphic gaps in the Paleocene and middle Miocene. Episodes of carbonate dissolution also occurred during the Paleocene at several sites, particularly at Site 549, where destruction of foraminiferal tests may obscure evidence of an unconformity. The middle Miocene hiatus is apparent at each site where Neogene sediments were continuously cored. Upper Miocene sediments at Site 550 (the only abyssal site) are characterized by moderate to extensive dissolution of planktonic foraminifers, but they contain abundant specimens of Bolboforma that mark this stratigraphic interval (von Daniels and Spiegler, 1974, doi:10.1007/BF02986990; Roegl, 1976, doi:10.2973/dsdp.proc.35.133.1976; Murray, 1979, doi:10.2973/dsdp.proc.48.116.1979; Müller et al., 1985, doi:10.2973/dsdp.proc.80.117.1985). Although foraminiferal evidence is not conclusive, nannofossils indicate a widespread Oligocene unconformity (Müller, 1985). Several oceanographic factors, not just simple sea-level change, probably interacted to produce these regional unconformities. There are also dramatic differences in the Cenozoic sedimentary record among Leg 80 sites, indicating that each has had a distinct geologic history. The thickness of the Cenozoic section varies from 100 m at Site 551 to 471 m at Site 548. The thickness of individual chronostratigraphic units also varies, as do the number and stratigraphic position of unconformities other than those mentioned. Differences in the stratigraphic record from site to site across the continental slope result from (1) location in separate half-graben structures, (2) varying location across the developing margin, and (3) difference in position relative to the seaward edge of the enclosing half-graben. Except for turbidites, deposition at Site 550 (abyssal) was largely independent of developments on the continental slope; but it was affected by oceanographic events widespread in the North Atlantic.