Case report: The histopathological analyses of two myelin oligodendrocyte glycoprotein antibody-associated diseases with a distinctive linear radiating gadolinium enhancement on MRI.

Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) has highly heterogeneous clinical presentations, in which encephalitis is an important phenotype. Moreover, MOGAD has been reported to exhibit diverse imaging findings. However, there have been no previous reports of cases with perivascular radial gadolinium enhancement in periventricular regions, commonly reported in autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy. In this paper, we present two cases of MOGAD with this MRI feature, both of which underwent brain biopsy for the lesions. Brain biopsies revealed perivenous demyelination and inflammation consistent with acute disseminated encephalomyelitis (ADEM), with pronounced axonal damage in Case 1 and minimal axonal involvement in Case 2. Case 1 exhibited more severe cerebral atrophy than Case 2, correlating with the extent of axonal damage. Through these cases, we highlight the heterogeneity of radiological manifestations of MOGAD, expanding the spectrum beyond previously defined MRI patterns. Furthermore, histopathological analysis revealed distinct axonal involvement as a potential prognostic marker of brain atrophy. These observations emphasize the importance of considering MOGAD in the differential diagnosis, even in cases with atypical imaging findings, and highlight the significance of brain biopsy in guiding both diagnosis and prognosis.

A case of Adult-onset Acute Flaccid Myelitis Accompanied by Rhombencephalitis which First Presented with Prominent Psychiatric Symptoms and Dysautonomia Mimicking Anti-N-methyl-d-aspartate Receptor Encephalitis.

A 44-year-old woman with a subacute onset of an altered mental status, urinary retention, and fluctuating blood pressure was initially diagnosed with anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis, meeting the criteria of Graus et al. Cardiac arrest occurred, which required pacemaker placement. She subsequently showed profound flaccid limb paralysis, with magnetic resonance imaging demonstrating focal necrotic lesions localized in the anterior horn of the longitudinal segments of the spinal cord and in the pontine tegmentum. Enteroviruses or autoimmune encephalitis-associated autoantibodies were not detected. We herein report a case of acute flaccid myelitis with profound psychiatric symptoms and dysautonomia, resembling NMDAR encephalitis.

Influence of pH and ion components in the liquid phase on the setting reaction of carbonate apatite granules.

Carbonate apatite (CO3Ap) is an inorganic component of bone and replaces by natural bone after implantation into the bone defect. Because of this unique characteristic, CO3Ap granules have been used in the dental field. However, washing out of granules from the bone defect area is an issue. The aim of this study was to set CO3Ap granules by mixing CO3Ap granules with acidic phosphate solutions and evaluate the influence of the pH and ion components of the solutions. When Na+ was the counter ion, the amount of precipitated dicalcium phosphate dihydrate (DCPD) was small and the setting ability disappeared with increasing pH of the solutions. Alternatively, when the counter ion was Ca2+, the amount of precipitated DCPD was high and the setting ability was observed even at high pH. These results suggest the presence of Ca2+ in the acidic phosphate solution is a key for fabricating CO3Ap granular cement.

[Rippling muscle disease with myasthenia gravis].

In February 2020, a 51-year-old woman experienced leg myalgia and noticed calf muscle movements that resembled a rippling wave while crouching down. In June 2020, she complained of bilateral arm myalgia. In August 2020, she developed left ptosis, had difficulty raising her bilateral arms, and developed diplopia and was admitted to our hospital. Anti-acetylcholine receptor antibodies turned out to be positive. We made a diagnosis of myasthenia gravis and acquired rippling muscle disease (RMD). Her myasthenia gravis symptoms and myalgia decreased with oral prednisolone. Contrast-enhanced computed tomography revealed thymoma. She underwent extended thymectomy and was discharged from the hospital. Her myalgia worsened, but it was responsive to methylprednisolone pulse therapy. CAV3 gene mutations are recognized as causes of congenial RMD whereas acquired RMD is associated with myasthenia gravis. Acquired RMD is rarely reported in Japan, but should be kept in mind as a condition treatable with immunotherapy.