Natural history of asymptomatic cervical internal carotid artery stenosis in diabetes mellitus patients.

INTRODUCTION: Diabetes mellitus (DM) is known to be a cause of cervical internal carotid artery stenosis (ICS). In this study, we investigated the natural history of asymptomatic ICS in DM patients without surgical intervention. METHODS: We conducted a retrospective study of 148 DM patients with asymptomatic ICS treated medically at the Kansai Electric Power Hospital from April 2013 to March 2023, inclusive. We examined the incidence of ischemic stroke with ICS and evaluated the patients' clinical characteristics and imaging findings. RESULTS: Ischemic stroke with ICS occurred in 7 patients (4.7 %), and only smoking history was significantly correlated with the incidence of ischemic stroke (p = 0.04). DISCUSSION: The incidence rate of ischemic stroke with ICS in this study (4.7%) was comparable to the previous report. The result that, the correlated factors of the incidence of ischemic stroke in DM patients with ICS was only smoking history, seemed acceptable. However, prospective studies with a larger number of cases may be needed in the future to determine the correlated factors more eligibly.

Twig-like middle cerebral artery as a variety of isolated middle cerebral artery disease with new vessel formation: illustrative case.

BACKGROUND: Twig-like middle cerebral artery (T-MCA) is reported as a rare vascular anomaly characterized by reconstitution of the M1 segment of the middle cerebral artery (MCA) by a plexiform network of small vessels. Although it is generally believed that the etiology of T-MCA is an embryological persistence, some investigators have suggested that T-MCA may be a secondary consequence. Here, the authors report a second case of de novo T-MCA formation and reconsider the concept of T-MCA in connection with isolated MCA disease. OBSERVATIONS: A 40-year-old man's brain magnetic resonance imaging (MRI) checkup showed moderate stenosis of the M1 segment of the left MCA. Annual MRI follow-up was planned, and when performed 1 year later, it showed occlusion of the M1 segment of the left MCA. Cerebral angiography revealed occlusion of that M1 segment with abnormal arterial networks. This case was diagnosed as de novo T-MCA. The patient has remained asymptomatic for 2 years. LESSONS: The reports of de novo T-MCA indicate that acquired factors may be involved in the pathogenesis of T-MCA. We suggest that T-MCA should be defined as a variety of isolated MCA disease with new vessel formation.

Moyamoya disease presenting with symptomatic ischemic stroke during new-generation tyrosine kinase inhibitor treatment: two illustrative cases.

Tyrosine kinase inhibitors (TKIs) have been widely used to treat chronic myeloid leukemia. Nilotinib and ponatinib, which are second- and third-generation TKIs, have been reported to cause cerebrovascular arterial complications. Here, we present two cases of moyamoya disease presenting with symptomatic ischemic stroke during new-generation TKI treatment. We judged that new-generation TKI treatment was a factor in symptomatic ischemic stroke of unknown moyamoya disease in both cases. Noninvasive examinations using magnetic resonance imaging or carotid ultrasonography should be performed before and during new-generation TKI treatment in order to prevent symptomatic ischemic stroke.

Consumption of N5, N10-methylenetetrahydrofolate in Thermus thermophilus under nutrient-poor condition.

TrmFO catalyzes the formation of 5-methyluridine at position 54 in tRNA and uses N5, N10-methylenetetrahydrofolate (CH2THF) as the methyl group donor. We found that the trmFO gene-disruptant strain of Thermus thermophilus, an extremely thermophilic eubacterium, can grow faster than the wild-type strain in the synthetic medium at 70°C (optimal growth temperature). Nucleoside analysis revealed that the majority of modifications were appropriately introduced into tRNA, showing that the limited nutrients are preferentially consumed in the tRNA modification systems. CH2THF is consumed not only for tRNA methylation by TrmFO but also for dTMP synthesis by ThyX and methionine synthesis by multiple steps including MetF reaction. In vivo experiment revealed that methylene group derived from serine was rapidly incorporated into DNA in the absence of TrmFO. Furthermore, the addition of thymidine to the medium accelerated growth speed of the wild-type strain. Moreover, in vitro experiments showed that TrmFO interfered with ThyX through consumption of CH2THF. Addition of methionine to the medium accelerated growth speed of wild-type strain and the activity of TrmFO was disturbed by MetF. Thus, the consumption of CH2THF by TrmFO has a negative effect on dTMP and methionine syntheses and results in the slow growth under a nutrient-poor condition.