In vitro binding analysis of legacy-linear and new generation-cyclic perfluoro-alkyl substances on sex hormone binding globulin and albumin, suggests low impact on serum hormone kinetics of testosterone.

In humans, serum testosterone (T) is largely bound to the sex hormone binding globulin (SHBG) and human serum albumin (hSA), resulting in a 2-3 % of unbound or "free" active quote (FT). Endocrine-disrupting chemicals, including perfluoro-alkyl substances (PFAS), are recognized to interfere with the hormonal axes, but the possible impact on the FT quote has not been addressed so far. Here we investigated the possible competition of two acknowledged PFAS molecules on T binding to SHBG and hSA. In particular, perfluoro-octanoic acid (PFOA) and acetic acid, 2,2-difluoro-2-((2,2,4,5-tetrafluoro-5(trifluoromethoxy)-1,3-dioxolan-4-yl)oxy)-ammonium salt (1:1) (C6O4) were used as, respectively, legacy-linear and new-generation-cyclic PFASs. Human recombinant SHBG 30-234 domain (SHBG30-234), produced in HEK293-F cells, and delipidated recombinant hSA were used as in vitro protein models. Isothermal Titration Calorimetry (ITC) and tryptophan fluorescence quencing (TFQ) were used to evaluate the binding modes of T and PFAS to SHBG30-234 and hSA. ITC revealed the binding of T to SHBG30-234 with a Kd of 44 ± 2 nM whilst both PFOA and C6O4 showed no binding activity. Results were confirmed by TFQ, since only T modified the fluorescence profile of SHBG30-234. In hSA, TFQ confirmed the binding of T on FA6 site of the protein. A similar binding mode was observed for PFOA but not for C6O4, as further verified by displacement experiments with T. Although both PFASs were previously shown to bind hSA, only PFOA is predicted to possibly compete with T for the binding to hSA. However, on the base of the binding stoichiometry and affinity of PFOA for hSA, this appears unlikely at the blood concentrations of the chemical documented to date.

SARS-CoV-2 S Mutations: A Lesson from the Viral World to Understand How Human Furin Works.

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is the etiological agent responsible for the worldwide pandemic and has now claimed millions of lives. The virus combines several unusual characteristics and an extraordinary ability to spread among humans. In particular, the dependence of the maturation of the envelope glycoprotein S from Furin enables the invasion and replication of the virus virtually within the entire body, since this cellular protease is ubiquitously expressed. Here, we analyzed the naturally occurring variation of the amino acids sequence around the cleavage site of S. We found that the virus grossly mutates preferentially at P positions, resulting in single residue replacements that associate with gain-of-function phenotypes in specific conditions. Interestingly, some combinations of amino acids are absent, despite the evidence supporting some cleavability of the respective synthetic surrogates. In any case, the polybasic signature is maintained and, as a consequence, Furin dependence is preserved. Thus, no escape variants to Furin are observed in the population. Overall, the SARS-CoV-2 system per se represents an outstanding example of the evolution of substrate-enzyme interaction, demonstrating a fast-tracked optimization of a protein stretch towards the Furin catalytic pocket. Ultimately, these data disclose important information for the development of drugs targeting Furin and Furin-dependent pathogens.

Cavernous carotid traumatic dissecting aneurysm and subarachnoid hemorrhage after orthognathic surgery treated with arterial embolization / Aneurisma dissecante traumático da carótica cavernosa e hemorragia subaracnóide a após cirurgia ortognática tratado com embolização arterial

Introdução: Dissecção aneurismática da artéria carótida interna em seu segmento cavernoso é uma lesão incomum, assim como sua associação com hemorragia subaracnóidea. Esta descrição é relatada com traumatismo direto ou indireto da região cervical. Apresentamos paciente masculino de 26 anos submetido a cirurgia ortognática que evoluiu em pós operatório imediato, com paralisia de nervos oculares direitos (IIIº°, IVº° e Vº°) oftalmoplegia, sem quemose ou proptose e com hemorragia subaracnóidea. A angiografia revelou aneurisma dissecante da artéria carótida interna direita em seu segmento cavernoso. Na evolução, apresentou ressangramento e a opção de tratamento foi a embolização arterial com micromolas de platina. Extensa revisão da literatura foi realizada, sendo proposto tratamento endovascular como opção terapeutica.

Introduction: Aneurysmal dissection of the internal carotidartery in the cavernous segment is an uncommon lesion,as well as the association with subarachnoid hemorrhage.Its description is related to direct or indirect trauma of theneck region. We report on a 26 year-old male patient whopresented in the imediate postoperative after an orthognathicsurgery with paralysis the right ocular cranial nerves (IIIº°, IVº ° and VIº°) with ophthalmoplegia, without chemosisor proptosis and with subarachnoid hemorrhage in thecranial tomography. Angiography disclosed a dissectinganeurysm of the right internal carotid artery in the cavernoussegment, presenting with rebleeding during his evolution. Thetherapeutic option was arterial embolization with platinummicrocoils. After extensive literature review, endovasculartreatment was suggested.