Particle decay in Gaussian wave-packet formalism revisited

Kenzo Ishikawa, Kin-ya Oda, Particle decay in Gaussian wave-packet formalism revisited, Progress of Theoretical and Experimental Physics, Volume 2018, Issue 12, December 2018, 123B01, https://doi.org/10.1093/ptep/pty127

Scalar scattering amplitude in the Gaussian wave-packet formalism

Kenzo Ishikawa, Kenji Nishiwaki, Kin-ya Oda, Scalar scattering amplitude in the Gaussian wave-packet formalism, Progress of Theoretical and Experimental Physics, Volume 2020, Issue 10, October 2020, 103B04, https://doi.org/10.1093/ptep/ptaa127

The carboxy-terminal fragment of α1A calcium channel preferentially aggregates in the cytoplasm of human spinocerebellar ataxia type 6 Purkinje cells

Spinocerebellar ataxia type 6 (SCA6) is an autosomal dominant neurodegenerative disease caused by a small polyglutamine (polyQ) expansion (control: 4–20Q; SCA6: 20–33Q) in the carboxyl(C)-terminal cytoplasmic domain of the α1A voltage-dependent calcium channel (Cav2.1). Although a 75–85-kDa Cav2.1 C-terminal fragment (CTF) is toxic in cultured cells, its existence in human brains and its role in SCA6 pathogenesis remains unknown. Here, we investigated whether the small polyQ expansion alters the expression pattern and intracellular distribution of Cav2.1 in human SCA6 brains. New antibodies against the Cav2.1 C-terminus were used in immunoblotting and immunohistochemistry. In the cerebella of six control individuals, the CTF was detected in sucrose- and SDS-soluble cytosolic fractions; in the cerebella of two SCA6 patients, it was additionally detected in SDS-insoluble cytosolic and sucrose-soluble nuclear fractions. In contrast, however, the CTF was not detected either in the nuclear fraction or in the SDS-insoluble cytosolic fraction of SCA6 extracerebellar tissues, indicating that the CTF being insoluble in the cytoplasm or mislocalized to the nucleus only in the SCA6 cerebellum. Immunohistochemistry revealed abundant aggregates in cell bodies and dendrites of SCA6 Purkinje cells (seven patients) but not in controls (n = 6). Recombinant CTF with a small polyQ expansion (rCTF-Q28) aggregated in cultured PC12 cells, but neither rCTF-Q13 (normal-length polyQ) nor full-length Cav2.1 with Q28 did. We conclude that SCA6 pathogenesis may be associated with the CTF, normally found in the cytoplasm, being aggregated in the cytoplasm and additionally distributed in the nucleus

Rare frequency of downbeat positioning nystagmus in spinocerebellar ataxia type 31

Spinocerebellar ataxia type 31 (SCA31) and spinocerebellar ataxia type 6 (SCA6) are the most frequent types of spinocerebellar degeneration in Japan. Previous reports described that it was difficult to distinguish SCA6 and SCA31 in clinical situations. There is not much difference except that the onset age of SCA31 is slightly higher than that of SCA6. Therefore we surveyed our medical records retrospectively, and then compared clinical symptoms of SCA6 and SCA31. As previously stated, the onset age of SCA31 is higher than that of SCA6. Gaze-evoked nystagmus is more frequent in SCA6 than in SCA31. The percentage in downbeat positioning nystagmus (DPN) is as high as 63% in SCA6. In contrast, DPN in SCA31 is rare and subtle. Our study suggests that the presence of DPN is an important sign that can differentiate SCA6 from SCA31 clinically

Gait disorders induced by photothrombotic cerebellar stroke in mice

Abstract Patients with cerebellar stroke display relatively mild ataxic gaits. These motor deficits often improve dramatically; however, the neural mechanisms of this improvement have yet to be elucidated. Previous studies in mouse models of gait ataxia, such as ho15J mice and cbln1-null mice, have shown that they have a dysfunction of parallel fiber-Purkinje cell synapses in the cerebellum. However, the effects of cerebellar stroke on the locomotor kinematics of wild-type mice are currently unknown. Here, we performed a kinematic analysis of gait ataxia caused by a photothrombotic stroke in the medial, vermal, and intermediate regions of the cerebellum of wild-type mice. We used the data and observations from this analysis to develop a model that will allow locomotive prognosis and indicate potential treatment regimens following a cerebellar stroke. Our analysis showed that mice performed poorly in a ladder rung test after a stroke. During walking on a treadmill, the mice with induced cerebellar stroke had an increased duty ratio of the hindlimb caused by shortened duration of the swing phase. Overall, our findings suggest that photothrombotic cerebellar infarction and kinematic gait analyses will provide a useful model for quantification of different types of acute management of cerebellar stroke in rodents