SARS-CoV-2 concentrations and virus-laden aerosol size distributions in outdoor air in north and south of Italy.

The COVID-19 disease spread at different rates in the different countries and in different regions of the same country, as happened in Italy. Transmission by contact or at close range due to large respiratory droplets is widely accepted, however, the role of airborne transmission due to small respiratory droplets emitted by infected individuals (also asymptomatic) is controversial. It was suggested that outdoor airborne transmission could play a role in determining the differences observed in the spread rate. Concentrations of virus-laden aerosol are still poorly known and contrasting results are reported, especially for outdoor environments. Here we investigated outdoor concentrations and size distributions of virus-laden aerosol simultaneously collected during the pandemic, in May 2020, in northern (Veneto) and southern (Apulia) regions of Italy. The two regions exhibited significantly different prevalence of COVID-19. Genetic material of SARS-CoV-2 (RNA) was determined, using both real time RT-PCR and ddPCR, in air samples collected using PM10 samplers and cascade impactors able to separate 12 size ranges from nanoparticles (diameter D < 0.056 µm) up to coarse particles (D > 18 µm). Air samples tested negative for the presence of SARS-CoV-2 at both sites, viral particles concentrations were <0.8 copies m-3 in PM10 and <0.4 copies m-3 in each size range investigated. Outdoor air in residential and urban areas was generally not infectious and safe for the public in both northern and southern Italy, with the possible exclusion of very crowded sites. Therefore, it is likely that outdoor airborne transmission does not explain the difference in the spread of COVID-19 observed in the two Italian regions.

Domoic acid at trace levels in lagoon waters: assessment of a method using internal standard quantification.

Domoic acid (DA) is a neurotoxin produced by different algae, including pennate diatoms, principally from the genus Pseudo-nitzschia, and it is the main cause of amnesic shellfish poisoning. Determination of this toxin in seawater samples is fundamental to define the real contamination risks for aquatic species. We have developed two very sensitive instrumental methods using hydrophilic interaction liquid chromatography coupled using tandem mass spectrometry in positive and negative polarity modes. Instrumental detection limits were 9 pg mL(-1) for positive and 19 pg mL(-1) for negative ionisation. A procedural method based on solid-phase extraction for the determination of dissolved DA present in seawater has been developed, and an extraction procedure was employed for the determination of the toxin in the particulate fraction. DA quantification was performed using the internal standard method to account for signals fluctuations and random errors during sample treatment. To our knowledge, this is the first study to use this quantification method for DA determination. Trueness, extraction yield, matrix effects, repeatability and procedural detection limits were evaluated during method validation. Procedural detection limits of 0.3 pg mL(-1) (positive mode) and 0.6 pg mL(-1) (negative mode) were found for the dissolved fraction, and absolute limits of 0.4 pg (positive mode) and 6.0 pg (negative mode) for particulate samples were obtained. The most sensitive method in positive mode was applied to define DA occurrence in the Venice Lagoon. Trace concentrations of domoic acid ranging from 1.5 to 16.2 pg mL(-1) were found for the first time in the Venetian environment.

Sinonasal inverted papilloma: 84 patients treated by endoscopy and proposal for a new classification.

AIM: To suggest a new classification system for sinonasal papilloma based on a critical analysis of surgical indications and results obtained. METHODS: We analysed surgical data from 84 cases of sinonasal papilloma treated endoscopically. RESULTS: In 58 males and 26 females, between 25 and 85 years, the ethmoid sinus (63 cases), the maxillary sinus (43), and the nasal fossa (22) were mostly involved. No case of endocranial extension or carcinoma was reported. Complications were reported in 15.4% of patients, as well as 5 recurrences (5.9%). Median follow up was 39,5 months. To categorise the tumour for the most appropriate surgical treatment, we propose a classification based on 6 main categories that depend on the location, origin and extension of the tumour. CONCLUSION: The classification that we propose presents advantages for prognosis and surgical indication in comparison with other classifications.

Interferon retreatment of patients with chronic hepatitis C. A long-term follow-up.

BACKGROUND/AIMS: We retrospectively evaluated the long-term efficacy of interferon retreatment in patients with chronic hepatitis C, who did not have a sustained response to a 1st cycle of treatment. METHODOLOGY: Sixty-six patients, 43 non-responder and 23 relapser to alpha interferon treatment, were retreated with alpha interferon, 6 MU thrice weekly for 12 months. Response was defined as negative HCV viremia. Responders underwent long-term follow-up (27-43 months). RESULTS: The response rates were 14% and 35% at the end of retreatment, 7% and 22% at 6 months, and 2% and 13% at long-term follow-up in non-responders and relapsers respectively. The outcome of retreatment was not statistically influenced by age, cirrhosis, viral genotype, dose and duration of previous treatment. CONCLUSIONS: Interferon retreatment, for sustained viral eradication, is not effective in non-responders and useful in few relapsers. Whereas, retreatment could prove effective in slowing down the activity of the disease and reducing the incidence of hepatocarcinoma, since some relapses occur late during the follow-up. Therefore, retreatment should be confined to relapsers with contraindications to new more efficient therapeutic strategies.