Biochemical features of genetic Creutzfeldt-Jakob disease with valine-to-isoleucine substitution at codon 180 on the prion protein gene.

Valine-to-isoleucine substitution at codon 180 of the prion protein gene is only observed in patients with Creutzfeldt-Jakob disease and accounts for approximately half of all cases of genetic prion disease in Japan. In the present study, we investigated the biochemical characteristics of valine-to-isoleucine substitution at codon 180 in the prion protein gene, using samples obtained from the autopsied brains of seven patients with genetic Creutzfeldt-Jakob disease exhibiting this mutation (diagnoses confirmed via neuropathological examination). Among these patients, we observed an absence of diglycosylated and monoglycosylated forms of PrPres at codon 181. Our findings further indicated that the abnormal prion proteins were composed of at least three components, although smaller carboxyl-terminal fragments were predominant. Western blot analyses revealed large amounts of PrPres in the cerebral neocortices, where neuropathological examination revealed marked spongiosis. Relatively smaller amounts of PrPres were detected in the hippocampus, where milder spongiosis was observed, than in the cerebral neocortex. These findings indicate that abnormal prion proteins in the neocortex are associated with severe toxicity, resulting in severe spongiosis. Our findings further indicate that the valine-to-isoleucine substitution is not a polymorphism, but rather an authentic pathogenic mutation associated with specific biochemical characteristics that differ from those observed in sporadic Creutzfeldt-Jakob disease.

CogEvo, a cognitive function balancer, is a sensitive and easy psychiatric test battery for age-related cognitive decline.

AIM: We examined whether a newly developed computer-aided neuropsychiatric series of test, CogEvo, is necessary and sufficient for the evaluation of cognitive function in older people. METHODS: A total of 272 participants in worthwhile life activity for the prevention of decline in mobility and cognitive function were administered tests every week at 33 locations in Fukaura-machi, Japan. Basic profile information, a Mini-Mental State Examination (MMSE), a CogEvo and a clock drawing test were used in the present study. RESULTS: Our results are summarized as: (i) the total score of the CogEvo and MMSE tests decreased significantly according to age and in age group analysis; (ii) scores from the CogEvo and MMSE tests showed a significant correlation; (iii) MMSE scores showed marked ceiling effects; (iv) analysis of cognitive domains, such as orientation, attention, memory and executive function, and spatial cognition using CogEvo showed significant age-dependent impairment; (v) CogEvo discriminated three score groups of MMSE results with sensitivity and specificity of 70% and 60% in the <23 score group, 78% and 54% in the 24-26 score group, and 85% and 70% in the >27 score group, respectively; (vi) CogEvo memory tests reflected more detailed recall function than registration function; and (vii) CogEvo spatial cognition test results were correlated with test items of the MMSE and clock drawing tests. CONCLUSIONS: CogEvo is an easy and potentially useful computer-aided test battery that can be used to evaluate age-related or pathological decline in cognitive function from middle age and in preclinical stages of dementia. Geriatr Gerontol Int 2019; ••: ••-••.

Orally active neurotrophin-enhancing agent protects against dysfunctions of the peripheral nerves in hyperglycemic animals.

Biological substances with neurotrophic activities, such as nerve growth factor (NGF) and monosialoganglioside GM1, have been considered as agents for diabetic peripheral neuropathy. Because recent studies have suggested that decreased availability of these substances might contribute to the pathogenesis of diabetic peripheral neuropathy, some clinical trials of NGF for diabetic peripheral neuropathy have been conducted and have led to mixed conclusions. The major reasons were its limited delivery to the nervous system and adverse effects induced by subcutaneous injection, which was necessary because NGF is a polypeptide. The current study investigates whether an orally active sialic acid derivative, MCC-257, has neuroprotective properties in diabetic peripheral nerves. MCC-257 augmented NGF activity in cultured dorsal root ganglia and PC12 (pheochromocytoma 12) cells. Treatment with MCC-257 elevated NGF levels in the sciatic nerve, accompanied by improvement in nerve conduction velocity in streptozotocin-induced diabetic animals. More importantly, MCC-257 ameliorated small fiber dysfunctions, including thermal hypoalgesia, substance P content, and histopathological innervation in the plantar skin of diabetic animals. Thus, the orally active neurotrophin enhancer provides a new option for the clinical treatment of diabetic peripheral neuropathy.

Chronic administration of a tyrosine kinase inhibitor restores functional and morphological changes of the basilar artery during chronic hypertension.

OBJECTIVE: Activation of tyrosine kinase appears to play an important role in pathogenesis of cardiovascular disease during chronic hypertension. In the present study, we tested the hypothesis that long-term treatment with an inhibitor of tyrosine kinase would have beneficial effects on hypertension-induced morphological and functional changes of the cerebral artery. METHODS: Male spontaneously hypertensive rats (SHR; 4 months old) were fed normal rat chow, or that containing an inhibitor of tyrosine kinase, genistein (1 mg/kg chow). Normotensive Wistar-Kyoto (WKY) rats were also fed either of the chows. After feeding the rats for 2 months, we measured wall thickness, diameter of the basilar artery and its dilator responses to acetylcholine (ACh); Y-26763, an opener of ATP-sensitive potassium channels; and Y-27632, an inhibitor of Rho-associated kinase. RESULTS: Treatment with genistein did not cause significant changes in physiological variables, including mean arterial pressure in either strain. In control SHR, the wall thickness of the basilar artery was greater than that of WKY rats. Genistein treatment reduced the wall thickness significantly in SHR. Vasodilator responses induced by ACh and Y-26763 were markedly attenuated in SHR compared to WKY rats, and treatment of SHR with genistein significantly improved the vasodilatation. Dilatation of the artery in response to Y-27632 was enhanced in SHR compared to WKY rats and treatment of SHR with genistein did not affect the enhanced vasodilator responses to Y-27632. CONCLUSIONS: Chronic treatment with genistein may be a novel approach to prevent cerebrovascular disorders.