OBJECTIVE: To evaluate outcomes achieved after implementing a treatment strategy for non-A non-B (NANB) (B 1-2 D according to the latest consensus document of the Society of Vascular Surgery (SVS) and Society of Thoracic Surgeons (STS) acute aortic dissection (AAD).
METHODS: This retrospective observational study adhered to the STROBE checklist. All cases of NANB AAD (B 1-2 D) treated at our Institution between January 2016 and December 2022 were reviewed. Morbidity, mortality, aortic-related reintervention, and remodelling were analysed.
RESULTS: Among 519 cases of acute aortic syndrome, n=22 (4.2%) patients presented with NANB AAD (B 1-2 D) (n=16,72.7% men, mean age 61.5 years+/14.7). Eleven cases were managed with best medical treatment (BMT) alone. Among them, one patient (9.1%) died suddenly two days after diagnosis for aortic rupture. Frozen elephant trunk procedure (FET) was required in the remaining 11 patients: 7(31.8%) needed emergent operation for risks of impending aortic rupture/retrograde AD extension and 4(26.7%) underwent delayed surgery within a month from initial presentation. Overall, in-hospital mortality was 9.1% with both FET and BMT. At a median follow-up of 40 months (range 2 days-200 months) no other deaths occurred. A statistically significant differences in the rate of FL thrombosis (100% vs 55.5%, p=.033) and a significant positive aortic remodelling in zone 3 (p<.001) and 4 (p=0.038) were reported in operated versus medically managed patients.
CONCLUSIONS: The best treatment for NANB is not established. We advocate for medical stabilisation with an operative approach that favours open surgery in the acute post dissection period, promotes aortic remodelling and carries acceptable risk in centres where FET is performed routinely.

AbstractThe Avian influenza virus is an infectious agent that may cause global health problem issues in poultry and potentially zoonotic. In recent decades, bacterial-derived sialidases have been extensively studied for their ability to inhibit avian influenza virus infections. In this study the antiviral activity of NanB sialidase from Pasteurella multocida was investigated through in vitro analysis using MDCK cells. NanB sialidase was purified from P. multocida for testing its toxicity and its ability to hydrolyze its sialic acid receptors on MDCK cells. H9N2 challenge virus was propagated in MDCK cells until cytopathic effects (CPE) appeared. Antiviral activity of NanB sialidase was conducted using MDCK cells, and then observed based on cell morphology, viral copy number, and expression of apoptosis-mediating genes. NanB sialidase effectively hydrolyzes Neu5Acα(2-6)Gal sialic acid at the dose of 129 mU/ml, while at 258 mU/ml it cause toxicity on MDCK cells. Antiviral activity of sialidase is evident based on the significantly decrease in viral copy number at all doses administrated. The increase of p53 and caspase-3 expression was observed in infected cells without sialidase. Our study demonstrates the ability of NanB sialidase to inhibit H9N2 virus replication based on observations of sialic acid hydrolysis, reduction in viral copy number, and expression of apoptosis-related genes. The future application of sialidase may be considered as an antiviral strategy against avian influenza H9N2 virus infections.

BACKGROUND: Non-A non-B (NANB) aortic dissections are uncommon and frequently unrecognized diseases. However, their proper identification is crucial given the unpredictable behavior of the dissected aorta with potential mortality and increased morbidity. We investigate the accuracy of radiological computed tomography angiography (CTA) reports in the diagnosis of acute NANB and the risk related to delayed recognition or misdiagnosis.
METHODS: The pretreatment contrast CTA of all consecutive patients admitted with acute aortic dissection (AAD) in a University Hospital in London (UK) between January 2017 and May 2023 were reviewed to retrospectively verify the accuracy of CTA reports in the diagnosis of NANB AAD (B1-2D The risk related to the delayed diagnosis (morbidity, mortality, and hospital readmissions) were evaluated as secondary outcomes. The study was conducted according to the Strengthening the Reporting of Observational Studies in Epidemiology guidelines.
RESULTS: Overall, 588 aortic CTAs were reviewed for a total of n = 393 (66.8%) type A AADs, n = 171 (29%) type B AADs and n = 25 (4.3%) NANB AADs (n = 16, 64% men, mean age 60.56, standard deviation ± 14.6 years). While no case of misdiagnosis was identified in Type A or B AAD groups, in NANBs only about a third of cases (n = 9, 36%) were immediately indicated as \"NANB\" (n = 2, 8%) or \"B with retrograde extension into the arch\" (n = 7, 28%), n = 8 cases (32%) were described generically as \"arch dissections\" (n = 6, 24%) or \"type A and B\" AAD (n = 2, 8%). The remaining 32% of patients received a diagnosis that did not include mention of the arch, as n = 6 (24%) cases were reported to be \"type A″ and n = 2 (8%) to be \"type B″ AADs. Despite the heterogeneity of terms used to describe NANB AAD, no case of cardiac tamponade, new onset malperfusion nor neurological complications were reported, and no sudden death nor home-discharge and readmission while waiting for the proper diagnosis.
CONCLUSIONS: The heterogeneity of terms used to describe NANB aortic dissection highlights the need for increased awareness, adoption of in guideline based classification systems, and further education to better understand and correctly address this challenging entity, minimizing misdiagnosis in ambiguous or difficult cases.

Sialidases are key virulence factors that remove sialic acid from host cell surface glycans, thus unmasking receptors to facilitate bacterial adherence and colonization. In this study, we report the isolation and characterization of novel inhibitors of the Streptococcus pneumoniae sialidases NanA, NanB, and NanC from Myristica fragrans seeds. Of the isolated compounds (1-12), malabaricone C showed the most pneumococcal sialidases inhibition (IC50 of 0.3μM for NanA, 3.6μM for NanB, and 2.9μM for NanC). These results suggested that malabaricone C and neolignans could be potential agents for combating S. pneumoniae infection agents.