DETECTION OF STX2 COLIPHAGES IN STRAIN OF ESCHERICHIA COLI ISOLATED FROM BOVINE FLEECE AND MILK FILTERS

Lambda(4)-phage vectors of gene codifying for synthesis of Shiga-toxins are suspected to be involved in the virulence evolution of Vero-Toxin producing Escherichia coli(VTEC). Herds of domestic or wild ruminants are reservoirs of these bacteria, but excretion with faeces is more frequent in groups of heifers and feeder calves. Studies have shown that slurries produced by infected herds are often positive for VTEC and that Stx2 carrying lambda coliphages can be isolated. These viruses can induce lysogenic cycles only in some strain of Escherichia coli and the Stx gene is then integrated in the bacterial chromosome. When these bacteria also posses other virulence traits, like those responsible for the intimate attachment to the enteric mucosal cells (eae or saa) the recombinant strains might became pathogen for humans. Our research was aimed at detecting the coliphages form ten Stx2 positive strains isolated in our previous studies. We have included strains, possessing or not the 'eae' genes. In addition we have used other isolates originating from slaughterhouses, with the aim of evaluating their susceptibility to the isolated 4-phages. Following induction of a lytic cycle with mitomycin C, the strains were screened by hybridization of plaque blots with Stx2 probes. The purified extracts of eight of the ten strains produced plaque/halos of lysis in cultures of susceptible strains, thus showing these strains were infected by inducible phages, but only one proved to be Stx2 carrier. Attempt to obtain new lysogens using the purified Stx2 phage with other strains 'eae' positive and STx negative isolated from slaughterhouses were unsuccessful. Stx2 lysogens were obtained only using the reference strains DM1187

Il Liceo classico oggi. Dieci voci per sceglierlo tra modernità e tradizione

Il volume raccoglie gli interventi di 8 docenti di ruolo nel Liceo classico, che descrivono le loro scelte metodologiche per innovare e migliorare l'insegnamento/apprendimento delle lingue classich

Blast waves from violent explosive activity at Yasur Volcano, Vanuatu

Infrasonic and seismic waveforms were collected during violent strombolian activity at Yasur Volcano (Vanuatu). Averaging similar to 3000 seismic events showed stable waveforms, evidencing a low-frequency (0.1-0.3Hz) signal preceding similar to 5-6s the explosion. Infrasonic waveforms were mostly asymmetric with a sharp compressive (5-106Pa) onset, followed by a small long-lasting rarefaction phase. Regardless of the pressure amplitude, the ratio between the positive and negative phases was constant. These waveform characteristics closely resembled blast waves. Infrared imagery showed an apparent cold spherical front similar to 20 m thick, which moved between 342 and 405m/s before the explosive hot gas/fragments cloud. We interpret this cold front as that produced by the vapor condensation induced by the passage of the shock front. We suggest that violent strombolian activity at Yasur was driven by supersonic dynamics with gas expanding at 1.1 Mach number inside the conduit

Pre-treatment high-sensitivity troponin T for the short-term prediction of cardiac outcomes in patients on immune checkpoint inhibitors

Background: Immune checkpoint inhibitors (ICIs) are an emerging option for several advanced metastatic cancers, but may have cardiotoxic effects. The prognostic value of high-sensitivity troponin T (hs-TnT) before treatment start has never been investigated. Materials and methods: Thirty consecutive patients underwent measurement of hs-TnT before starting ICI therapy (pembrolizumab, 23%; nivolumab, 12%; atezolizumab, 6%; durvalumab, 5%). The primary endpoint of cardiovascular death, stroke or transient ischaemic attack, pulmonary embolism and new-onset heart failure, and the secondary endpoint of progression of cardiac involvement according to the CARDIOTOX classification were evaluated after 3 months from the first cycle. Results: Patients (median age 68 years, 77% men, 13% with coronary artery disease, 90% current or former smokers, 67% overweight or obese and 43% hypertensive) had a median hs-TnT of 12 ng/L (interquartile interval 8-23). The primary endpoint occurred only in patients with hs-TnT ≥ 14 ng/L at baseline. Therefore, only patients who had hs-TnT ≥ 14 ng/L before the first cycle died had a stroke/TIA or new-onset HF. Furthermore, nine out of 13 patients with the secondary endpoint (progression of cardiac disease) had hs-TnT ≥ 14 ng/L before the first cycle (P =.012). AUC values were 0.909 for the primary endpoint and 0.757 for the secondary endpoint. The best cut-off was 14 ng/L for both the primary (100% sensitivity, 73% specificity) and secondary endpoints (sensitivity 75%, specificity 77%). Conclusions: In patients on ICIs, baseline hs-TnT predicts a composite cardiovascular endpoint and the progression of cardiac involvement at 3 months, with 14 ng/L as the best cut-off