Disturbance in the protein landscape of cochlear perilymph in an Alzheimer's disease mouse model.

Hearing loss is a pivotal risk factor for dementia. It has recently emerged that a disruption in the intercommunication between the cochlea and brain is a key process in the initiation and progression of this disease. However, whether the cochlear properties can be influenced by pathological signals associated with dementia remains unclear. In this study, using a mouse model of Alzheimer's disease (AD), we investigated the impacts of the AD-like amyloid ß (Aß) pathology in the brain on the cochlea. Despite little detectable change in the age-related shift of the hearing threshold, we observed quantitative and qualitative alterations in the protein profile in perilymph, an extracellular fluid that fills the path of sound waves in the cochlea. Our findings highlight the potential contribution of Aß pathology in the brain to the disturbance of cochlear homeostasis.

Development of infectious mononucleosis as an unusual manifestation of COVID-19.

It has generally been reported that patients with COVID-19 show a fever, cough, and/or respiratory failure as the most common clinical symptoms but some have unusual symptoms, such as anosmia, diarrhea, and throat pain. We herein report a 26-year-old woman with chief complaints of lymphadenopathy and a fever. First, she underwent a laboratory examination, which showed a high proportion of atypical lymphocytes (19%) and an increase in hepatic enzyme activities, and was then hospitalized with a diagnosis of infectious mononucleosis (IM). However, the blood examination did not show any increase in anti-Epstein-Barr virus VCM-IgM. Subsequently, she developed tonsillar hypertrophy with purulent plugs. An additional examination for infection of other pathogens revealed positivity only for SARS-CoV-2 in a loop-mediated isothermal amplification (LAMP) test. The patient was transferred to the COVID-19-specific isolation ward, and none of the ward staff, patients, or either of the two otolaryngologists who had directly examined this patient showed positive signs for SARS-CoV-2 in a LAMP test. Consequently, this case suggests that even if patients show clinical symptoms and signs of common diseases for otolaryngologists, such as IM, we should keep in mind the possibility of COVID-19 without arbitrarily assuming that IM is caused by Epstein-Barr virus.

SIRT7 has a critical role in bone formation by regulating lysine acylation of SP7/Osterix.

SP7/Osterix (OSX) is a master regulatory transcription factor that activates a variety of genes during differentiation of osteoblasts. However, the influence of post-translational modifications on the regulation of its transactivation activity is largely unknown. Here, we report that sirtuins, which are NAD(+)-dependent deacylases, regulate lysine deacylation-mediated transactivation of OSX. Germline Sirt7 knockout mice develop severe osteopenia characterized by decreased bone formation and an increase of osteoclasts. Similarly, osteoblast-specific Sirt7 knockout mice showed attenuated bone formation. Interaction of SIRT7 with OSX leads to the activation of transactivation by OSX without altering its protein expression. Deacylation of lysine (K) 368 in the C-terminal region of OSX by SIRT7 promote its N-terminal transactivation activity. In addition, SIRT7-mediated deacylation of K368 also facilitates depropionylation of OSX by SIRT1, thereby increasing OSX transactivation activity. In conclusion, our findings suggest that SIRT7 has a critical role in bone formation by regulating acylation of OSX.

Surfactant-free solution-dispersible Si nanocrystals surface modification by impurity control.

Si nanocrystals (Si-NCs) dispersible in polar liquid without surface functionalization by organic molecules have been realized by simultaneously doping n and p type impurities. We show that the codoped Si-NCs are stable in methanol for more than five months, while intrinsic Si-NCs prepared by the same procedure form large agglomerates. The different behavior of the intrinsic and codoped Si-NCs in solutions suggests that doped impurities exist on the surface of Si-NCs and the surface potential is large enough to prevent the agglomeration. The colloidal solution of codoped Si-NCs exhibits broad photoluminescence with the maximum in the near infrared range (1.1-1.3 eV).

Long-term outcome of type B aortic intramural hematoma: comparison with classic aortic dissection treated by the same therapeutic strategy.

BACKGROUND: The long-term clinical course and therapeutic strategy of patients with type B aortic intramural hematoma (IMH) are not completely known. The purpose of this study was to clarify long-term prognosis of patients with type B IMH by comparison with type B classic aortic dissection (AD). METHODS: Clinical data were compared retrospectively between 37 patients with acute type B IMH (IMH group) and 69 patients with acute type B AD (AD group). Our therapeutic strategy for all patients was medical therapy with frequent follow-up imaging studies and timed surgical repair in cases with progression. RESULTS: Initially, medical therapy was selected for 104 of 106 (98%) patients. In two patients of the AD group, immediate surgical treatment was performed because of aortic rupture. As for complications, no significant difference was seen between the two groups. There was no significant difference in the incidence of the total number of deaths; early death, late death, or causes of deaths. The actuarial survival rates for the IMH group at 1, 2, 5, and 10 years were 97 +/- 3, 97 +/- 3, 85 +/- 9, and 85 +/- 9%, respectively; the values were 96 +/- 1, 96 +/- 1, 89 +/- 4, and 71 +/- 9%, for the AD group. The actuarial survival rates of the two groups were not significantly different from each other (p = 0.398). CONCLUSIONS: Patients with type B IMH have similar long-term prognosis to patients with type B AD. Medical therapy with frequent follow-up imaging studies and timed surgical repair in cases with progression can be a rational therapeutic strategy in patients with type B IMH.