From delta to Omicron: S1-RBD/S2 mutation/deletion equilibrium in SARS-CoV-2 defined variants.

Coronavirus-related Severe Acute Respiratory Syndrome (SARS-CoV) in 2002/2003, Middle-East Respiratory Syndrome (MERS-CoV) in 2012/2013, and especially the current 2019/2021 Severe Acute Respiratory Syndrome-2 (SARS-CoV-2) affected negatively the national health systems' endurance worldwide. SARS-Cov-2 virus belongs to lineage b of beta-CoVs demonstrating a strong phylogenetic similarity with BatCoVRaTG13 type. Spike (S) glycoprotein projections -consisting of two subunits S1/S2- provide a unique crown-like formation (corona) on virion's surface. Concerning their functional role, S1 represents the main receptor-binding domain (RBD), whereas S2 is involved in the virus-cell membrane fusion mechanism. On Nov 26th 2021, WHO designated the new SARS-CoV-2 strain - named Omicron, from letter ''όµÎ¹κρον'' in the Greek alphabet - as a variant of concern (B.1.1529 variant). Potentially this new variant is associated with high transmissibility leading to elevated infectivity and probably increased re-infection rates. Its impact on morbidity/mortality remains under investigation. In the current paper, analyzing and comparing the alterations of SARS-CoV-2 S RNA sequences in the defined variants (Alpha to Omicron), we observed some interesting findings regarding the S1-RBD/S2 mutation/deletion equilibrium that maybe affect and modify its activity.

Suicidal behavior in a patient with burning mouth syndrome.

Introduction. Chronic pain of the oral cavity is a long-term condition and like all other types of chronic pain is associated with numerous comorbidities such as depression or anxiety. Case Presentation. This is a case of a 93-year-old patient suffering from chronic oral cavity pain who repeatedly stabbed his palate due to ongoing local pain, over the last few months, which he could not further tolerate. The patient was suffering from depression and also a diagnosis of "burning mouth syndrome" (BMS) was made. Discussion. Burning mouth syndrome (BMS) is characterized by a burning sensation in the tongue or other oral sites. BMS has high psychiatric comorbidity but can occur in the absence of psychiatric diagnosis. Patients with multiple forms of pain must be considered as potential candidates for underdiagnosed depression (major) and suicidal thoughts.