益子 貴史

BACKGROUND: The relationship between transesophageal echocardiography findings and cognitive function. OBJECTIVE: This study aimed to establish an association between transesophageal echocardiography findings and cognitive function in stroke survivors. METHODS: A single-center study was conducted between April 1, 2017 and March 31, 2022. All subjects that were included had a past history of ischemic stroke and were admitted after >21 days from onset. The participants underwent cognitive function tests including a Mini-Mental State Examination, Revised Hasegawa Dementia Scale, Frontal Assessment Battery, and transesophageal echocardiography. RESULTS: The results of 126 participants were analyzed. The cognitive function of participants with a spontaneous echo contrast (+) in the left atrium including appendage or of those with an aorta-arch plaque with a maximum thickness ≥4 mm significantly worse while neither the patent foramen ovale nor the branch extending plaque influenced cognitive function (The median cognitive scores of the spontaneous echo contrast (-) versus (+) were 26 versus 22, p < 0.01**, 26 versus 21, p < 0.001***, and 14 versus 11, p < 0.01**. Those of the aortic-arch plaque max thickness (<4 mm) versus (≥4 mm) were 26 versus 25, p < 0.05*, 27 versus 24, p < 0.05*, and 15 versus 13, p < 0.05*). CONCLUSION: Our findings show that spontaneous echo contrast in the left atrium and aortic-arch atheroma detected by transesophageal echocardiography, were negatively associated with cognitive function.

BACKGROUND: It is important to gauge mortality in real time following an ischemic stroke. However, there is limited in-hospital and post-discharge clinical data that focuses on the real-time prognosis of acute ischemic strokes. PURPOSE: To comprehensively analyze ischemic stroke mortality during a hospital stay and 1 year after the onset of a stroke. MATERIALS AND METHODS: Initially, 1514 consecutive acute ischemic stroke patients were admitted to our facility within 7 days after the onset of a stroke. Of these, 1116 patients who were successfully surveyed 1 year after onset were finally analyzed. Baseline, physical, laboratory, and stroke clinical data were recorded and analyzed. RESULTS: The proportion of deaths within 1 year was 14.5%, 4.9% without discharge was and 9.6% after discharge within 1 year. Cardioembolic ischemic strokes were responsible for nearly 50% of the deaths within 1 year while the remaining deaths were due to non-cardioembolic ischemic strokes. After 1 year, survival rate in the hospital decreased significantly, depending on whether the stroke was recurrent or if there was bleeding without a stroke. CONCLUSIONS: Our study reveals the real-time survival data 1 year after the onset of a stroke, in-hospital and post-discharge mortality rates, and several issues associated with the treatment of acute ischemic strokes.

We herein report a 70-year-old man diagnosed with IgG4-related hypertrophic pachymeningitis with skull base involvement, who presented with isolated glossopharyngeal and vagus nerve palsy. Contrast-enhanced magnetic resonance imaging (MRI) showed enhanced dural thickening of the posterior clivus and skull base involvement. When a patient with hypertrophic pachymeningitis presents with isolated cranial neuropathy without systemic manifestations or definite MRI abnormalities, it is difficult to make a diagnosis, and the patient may be misdiagnosed. This case suggests that a detailed radiological evaluation including contrast enhancement of the skull base is very important in patients with isolated glossopharyngeal and vagus nerve palsy.

BACKGROUND AND PURPOSE: Multiple embolic sources are sometimes observed simultaneously in patients with embolic stroke. The present study investigated the effects of coexisting aortic arch atheroma ≥ 4 mm thick and atrial fibrillation (AF) on short-term stroke recurrence and functional outcome. METHODS: Transesophageal echocardiography (TEE) was performed in consecutive embolic stroke patients, and 395 patients were classified into 4 groups according to the presence of aortic arch atheroma ≥ 4 mm thick and AF: AF - /ARCH - group, AF + /ARCH - group, AF - /ARCH + group, and AF + /ARCH + group. In accordance with these 4 groups, we evaluated stroke recurrence and all-cause death for 3 months after stroke onset, and also evaluated the 3-month functional outcome using the modified Rankin scale (mRS). RESULTS: Among the 128 AF patients, 39.1% also had aortic arch atheroma ≥ 4 mm thick. Of the 395 enrolled cases, the AF + /ARCH + group showed the highest frequencies of stroke recurrence and all-cause death during 3 months after onset. On multivariate analysis, stroke recurrence or all-cause death during 3 months after onset was relatively more frequent in the AF + /ARCH + group than in the AF + /ARCH - group (OR, 2.34; 95% CI, 0.82-6.69; p = 0.11), but that was not statistically significant, and poor functional outcome (mRS score 3-6) at 3 months was significantly more frequent in the AF + /ARCH + group than in the AF + /ARCH - group (OR, 2.59; 95% CI, 1.08-6.24; p = 0.0339). CONCLUSIONS: Aortic arch atheroma concomitant with AF is not rare and appears associated with increased risks of stroke recurrence and poor functional outcome.

BACKGROUND AND PURPOSE: Prescribing under-dose direct oral anticoagulants (DOACs) for non-valvular atrial fibrillation (NVAF) is alerted to increase cardiovascular events or death. However, the association between dose selection of DOACs and the clinical course remains unclear. This study aimed to propose a novel criterion for selecting the DOAC dose and investigate clinical characteristics of ischemic stroke (IS) under this criterion. METHODS: We assessed the pooled prospective multicenter registry data of stroke patients taking anticoagulant agents, including IS patients with NVAF and prior DOAC usage. The recommended dose according to the reduction criteria of each DOAC and the selected dose were identified for each patient, and patients were categorized into four groups: no alternative low-dose, selecting low-dose appropriately with all DOACs applicable for reduction criteria; selected low-dose, selecting low-dose appropriately or inappropriately despite at least one DOAC inapplicable for reduction criteria; selected standard-dose, appropriate standard-dose use; and absolute over-dose, inappropriate standard-dose regardless of criteria. We investigated the effects of dose selection of DOACs on short-term poor functional outcomes. RESULTS: 322 patients were included in the analysis. The prevalence of no alternative low-dose, selected low-dose, selected standard-dose, and absolute over-dose was 74 (23%), 144 (45%), 89 (27%), and 15 (5%), respectively. Multivariable analysis found that the selected low-dose group showed significantly poorer functional outcomes than the selected standard-dose group only in patients without renal dysfunction (OR, 2.60; 95% CI, 1.17-6.00; P = 0.0186). CONCLUSIONS: Selecting a low dose DOAC might be associated with poor functional outcomes in patients without renal dysfunction.

BACKGROUND: Although the relationship between amyotrophic lateral sclerosis (ALS) and cervical spondylotic myelopathy (CSM) is important, data relating to CSM complications in ALS remain lacking. PURPOSE: We aimed to investigate and validate the spinal cord conditions of ALS patients. MATERIALS AND METHODS: We recruited all patients diagnosed with ALS, Parkinson's disease (PD), or chronic inflammatory demyelinating polyneuropathy (CIDP) who were admitted to our department from April 1, 2017, to March 31, 2020. We analyzed the cervical or thoracolumbar magnetic resonance imaging (MRI) scans of these 128 patients. Data relating to spondylosis, cord compression, spinal canal diameter, spinal cord diameter, and the closest distance between the cervical spinal canal and cord were validated using MRI. RESULTS: Of the 128 patients, 52 had ALS, 48 had PD, and 28 had CIDP. The proportions of both cervical spondylosis and cervical cord compression were highest in the ALS group compared with the other patient groups (p < 0.05). The proportion of cervical spondylosis in ALS patients reached 38.3%, and that of cervical cord compression reached 53.2%. The closest distance between the cervical spinal canal and cord was also significantly smaller in ALS patients compared with CIDP patients (p < 0.05). In contrast to the cervical cord findings, there were no significant differences in the thoracolumbar cord between ALS patients and the other patient groups. CONCLUSIONS: Of the three disease groups, the proportion of CSM was highest in ALS patients. Furthermore, cervical cord conditions were significantly more crowded in the ALS patients than in the other patient groups.

Recent reports suggest that Staphylococcus haemolyticus can cause infective endocarditis (IE). However, no data are available regarding infectious intracranial aneurysm (IIA) following S. haemolyticus endocarditis. Endovascular coiling is a challenging approach for the treatment of IIA. We describe the case of a 63-year-old woman who suddenly developed aphasia and dysarthria following an acute cerebral infarction in her left insular and temporal cortex. After a total hysterectomy at the age of 39, the patient had suffered from recurrent bacterial pyomyositis in her legs. At admission, there was no evidence of cerebral aneurysm, as assessed by magnetic resonance angiography, and no vegetation, as assessed by transesophageal echocardiography (TEE), resulting in an incorrect diagnosis. However, subarachnoid hemorrhage and development of cerebral aneurysm in the left middle cerebral artery occurred within 1 week of hospitalization. Continuous positive blood culture results and a second TEE finally revealed that IE was caused by S. haemolyticus. Coil embolization of the IIA was successful on day 26 after symptom onset; after this procedure, the patient began to recover. This case demonstrates that S. haemolyticus-induced endocarditis can cause IIA. Endovascular coiling is a potentially effective approach to treat IIA.

Primary central nervous system lymphoma (PCNSL) is a rare form of non-Hodgkin lymphoma, but its diagnosis is challenging in some cases. A brain biopsy is the gold standard for diagnosing PCNSL, but its invasiveness can be problematic. Thus, noninvasive imaging examinations have been developed for the pre-surgical diagnosis of PCNSL, including gadolinium-enhanced magnetic resonance imaging (MRI), 123I-N-isopropyl-p-iodoamphetamine single-photon emission computed tomography (123I-IMP SPECT), and positron emission tomography with 18F-fluorodeoxyglucose (18F-FDG PET). Here, we report the case of a 71-year-old woman with negative imaging findings for PCNSL, but who was diagnosed with PCNSL by a brain biopsy and histological analysis. Her imaging results were negative for gadolinium-enhanced cranial MRI, with low uptake in 123I-IMP SPECT and hypometabolism in 18F-FDG PET. However, a stereotactic brain biopsy from an abnormal lesion revealed that many round cells had infiltrated into the brain. Moreover, many infiltrating cells were positive for cluster of differentiation (CD)20 and CD79a, and proliferation marker protein Ki-67-positive cells accounted for nearly 80% of all cells. Based on these results, our final pathological diagnosis was PCNSL. The present case highlights the possibility of a PCNSL diagnosis even when all imaging-related examinations display negative results.

Cardiac involvement has recently been the focus of sporadic late-onset nemaline myopathy (SLONM). However, right ventricular failure and pulmonary hypertension, in addition to repetitive cardiac arrest, are noteworthy characteristics of SLONM. We herein report a 66-year-old woman with SLONM whose main symptoms were cardiac arrest, right ventricular failure, and pulmonary hypertension. Despite permanent pacemaker replacement, cardiac arrest occurred repetitively, and even with continuous positive airway pressure, right ventricular failure and pulmonary hypertension persisted. The patient was finally diagnosed with SLONM by a muscle biopsy. Our case suggests the possibility of cardiovascular involvement in SLONM, especially right ventricular failure and pulmonary hypertension.

AIM: Aortic arch atherosclerosis, particularly complex aortic arch plaques (CAPs), is an important source of cerebral emboli. CAPs and atrial fibrillation (AF) often co-exist; however, the prevalence and risk of CAPs in acute ischemic stroke patients with AF is unclear. METHODS: In patients with acute ischemic stroke with non-valvular AF admitted to Jichi Medical University Hospital during April 2016 to September 2019, we retrospectively evaluated the presence of CAPs on transesophageal echocardiography (TEE). RESULTS: CAPs were observed in 41 (38.7 %) of 106 patients with non-valvular AF. Older age, diabetes mellitus, chronic kidney disease, low high-density lipoprotein cholesterol (HDL-C) levels, higher levels of glycohemoglobin A1c (HbA1c), higher CHADS2 and CHA2DS2-VASc scores, and intracranial or carotid artery stenosis were more frequently observed in CAPs-positive than in CAPs-negative patients. In multivariable analyses, older age (odds ratio [OR]: 1.2 per year increase; 95% confidence interval [CI]: 1.07-1.24; P＜0.0001), diabetes mellitus (OR: 4.7; 95%CI: 1.27-17.35; P＜0.05), and low HDL-C (OR: 0.95 per 1 mg/dl increase; 95%CI: 0.92-0.99; P＜0.01) were independent risk factors for CAPs. The prevalence of CAPs was age-dependent, and there was a significantly higher risk in patients aged either 75-84 years or ＞84 years than in those aged ＜65 (OR: 7.6; 95%CI: 1.50-38.62, and OR: 32.1; 95%CI: 5.14-200.11, respectively). CONCLUSIONS: Even in patients with ischemic stroke with non-valvular AF, concomitant CAPs should be considered in older individuals and those who have diabetes or low HDL-C.

The treatment of ischemic stroke has recently witnessed dramatic developments. However, there are limited data on ischemic stroke characteristics in aged patients. As part of the South Tochigi Acute Ischemic Stroke Registry, we prospectively enrolled 636 consecutive acute ischemic stroke patients (within 7 days after the onset) who were ≥ 60 years of age and who were admitted to two independent institutes from April 1, 2016 to February 28, 2019. We analyzed three groups divided by age: early-aged (60-69 years), middle-aged (70-79 years), and oldest-aged (≥ 80 years). From the 636 subjects, 194 were early-aged, 215 were middle-aged, and 227 were oldest-aged. There were significant differences in the ischemic stroke subtypes in each aging group (p < 0.01). The proportion of cardioembolism was 22.2% in early-aged, 27.4% in middle-aged, and 41.4% in the oldest-aged patients. The proportion of patients with a modified Rankin Scale of 0-2 at 1 year after onset decreased to 42.2% in middle-aged and 17.8% in oldest-aged with cardioembolic ischemic stroke. The proportion of patients receiving anticoagulation therapy before admission was 25.6% (36.7% of atrial fibrillation [AF]) in early-aged, 39.0% (52.3% of AF) in middle-aged, and 18.1% (21.0% of AF) in oldest-aged patients (p < 0.001). Our study reports characteristics of clinical ischemic stroke in an aging population. The assessment of cardiogenic embolism is important for an aging population.

BACKGROUND: Many issues persist in the today's Alzheimer's disease (AD) screening and the breakthrough method is desired. OBJECTIVE: We aim to validate the association between venous reflux and AD, and to develop a new method for AD screening. METHODS: We examined spontaneous echo contrast, area, diameter, retrograde velocity, and anterograde velocity of the bilateral cervical internal jugular vein (IJV) using carotid ultrasonography. RESULTS: A total of 112 patients participated in this study, with 26 diagnosed as AD. The proportion of both or either IJV spontaneous echo contrast (+) occupied 25 of total 26 AD patients, which showed 96.2%of sensitivity and 98.5%negative predictive value. The IJV velocities also showed significant correlation with AD diagnosis, although the IJV area or diameter did not. CONCLUSION: Our results indicate that the validation of the spontaneous echo contrast or velocities of the IJV are convenient AD diagnosis screening methods and that the venous reflux disturbance correlates with AD development.

BACKGROUND: In patients with lower lateral medullary infarction (LMI) located under the vestibular nucleus, proprioceptive impairment due to dorsal spinocerebellar tract (DSCT) is considered a pathological condition for body lateropulsion. In patients with brainstem infarction located at or above the level of the vestibular nucleus, other pathways, such as the crossed vestibulothalamic tract (CVTT), are considered responsible. RESEARCH QUESTION: The clinical course of body lateropulsion between each anatomical level of infarction remains unclear. Further, whether body lateropulsion refers to a static or a dynamic symptom also remains unclear. METHODS: We examined 47 patients who exhibited body lateropulsion and categorized them into four groups: lower LMI under the vestibular nucleus, LMI at the level of the vestibular nucleus, pontine infarction, and midbrain infarction. The patients' time to acquire static upright standing position and gait in a straight line were statistically analyzed by a log-rank test using the Kaplan-Meier method. RESULTS: Body lateropulsion in the static upright position was less frequent in the lower LMI group than in the other groups. SIGNIFICANCE: Lower LMI primarily affected body lateropulsion in gait. DSCT damage could affect ipsilateral hip joint or leg coordination, causing body lateropulsion in dynamic situation.

OBJECTIVES: Magnetic resonance angiography (MRA), three-dimensional computed tomography angiography, and cerebral angiography may be used to assess intracranial vertebrobasilar stenosis. However, these examinations cannot be performed at patients' bedsides. Our purpose was to develop a new bedside method to assess intracranial vertebrobasilar arterial stenosis. METHODS: We developed the new method using carotid duplex ultrasonography combined with the head-up test. A total of 141 subjects admitted between June 1, 2017 and March 31, 2019 were enrolled in this study. We calculated vertebral arterial peak systolic velocities (PSVs), end-diastolic velocities (EDVs), and mean velocities (MVs) at 0°, 16°, and 30° head-up angles. Vertebrobasilar arterial stenosis was confirmed using MRA. RESULTS: We excluded 28 subjects and included data for 113 subjects and 226 vessels in the final analysis. Cervical vertebral arterial PSV, EDV, and MV gradually decreased from 0° to 30° only in stenotic intracranial vertebral arteries. Sensitivity (probability of detection) was 75.5% and specificity (true negative rate) was 79.7% when EDV at the 30° head-up angle decreased ≥19.5% from the initial 0° head-up angle. Specificity was better (86.4%; sensitivity: 69.4%) when EDV was <9.1 cm/s at the 30° head-up angle. CONCLUSION: This new method easily detects intracranial vertebrobasilar arterial stenosis.

Cerebral amyloid angiopathy-related inflammation is a syndrome of reversible encephalopathy with cerebral amyloid angiopathy, however the pathology is not well understood. We clear a part of the pathology through the first case of an 80-year-old man with cerebral amyloid angiopathy-related inflammation induced by relapsing polychondritis (RP) analysis. An 80-year-old man was diagnosed with RP by auricular cartilage biopsy. Almost no abnormality including intracranial microbleeding was detected by cranial magnetic resonance image (MRI) at diagnosis. However, he developed a headache and hallucination after five months. Seven-month cranial MRI showed novel, multiple, intracranial microbleeding, especially in the bilateral but asymmetry posterior, temporal, and parietal lobes. 123I-N-isopropyl-p-iodoamphetamine single-photon emission computed tomography showed increased cerebral blood flow in the bilateral posterior lobes. After treatment, both of his neurological symptoms and increased cerebral blood flow improved to mild. Photon emission computed tomography using Pittsburgh compound B (PiB) for evaluation of brain amyloidosis at 12 months after onset showed an amyloid deposit in the bilateral frontal lobes, but a lack of uptake corresponded to the RP lesions. Our case suggests that inflammation coupled with an amyloid deposit, induced the multiple intracranial bleeding, and resulted in the lack of PiB uptake. Findings from our case show that inflammation including excess blood flow coupled with an amyloid deposit synergistically facilitate intracranial bleeding.

Data presented in this article are related to our article entitled "Unilateral posterior reversible encephalopathy syndrome: A case report" [1]. Cases of Posterior Reversible Encephalopathy Syndrome (PRES) involving unilateral lesions are very rare. We searched the PubMed database using keywords such as PRES, unilateral, and asymmetric and found a small number of cases to include in our review. We summarized the characteristics of these reported cases of unilateral PRES, including our case.

Isolated vertigo is an important symptom of posterior circulation stroke. It has been reported that 11.3% of patients with isolated vertigo have a stroke and that most lesions are located in the cerebellum, particularly in the posterior inferior cerebellar artery. We report the case of a 63-year-old man with multiple atherosclerotic risk factors and atrial fibrillation who showed repeated episodes of isolated vertigo. His repeated vertigo was short-lasting and was often triggered by body position, mimicking benign paroxysmal positional vertigo. Cranial computed tomography on the third hospital day showed left cerebellar infarction within the territory of the posterior inferior cerebellar artery. The vertigo was ameliorated on the fifth hospital day and warfarin was prescribed for secondary prevention. Clinicians should pay special attention to cases in which a patient presents isolated vertigo, even if it shows transient recurrence or is triggered by a positional change, especially in patients with multiple cerebrovascular risk factors.

Fatalities following intravenous recombinant tissue-type plasminogen activator therapy have been reported. Major fatal complications following intravenous recombinant tissue-type plasminogen activator therapy include intracranial hemorrhage, aortic dissection, and extracranial bleeding. However, the possibility that intravenous recombinant tissue-type plasminogen activator therapy itself paradoxically induces synchronized multiple cerebral novel infarctions has never been considered. We herein report the first case of bilateral internal carotid artery infarction with onset seizure following intravenous recombinant tissue-type plasminogen activator therapy for a vertebral-basilar artery infarction. A 75-year-old man was transferred to our hospital and diagnosed with acute ischemic stroke in the basilar artery. His National Institute of Health Stroke Scale score was 4. The intravenous recombinant tissue-type plasminogen activator therapy was initiated 234 minutes after stroke onset because no contraindications were present. Almost 2 hours after the intravenous recombinant tissue-type plasminogen activator therapy, the patient suddenly fell into a deep coma with generalized convulsions. A huge secondary infarction was found in the bilateral anterior circulation territories, and he died 7 days after stroke onset. This case alerts clinicians to the possibility of synchronized multiple cerebral infarctions following intravenous recombinant tissue-type plasminogen activator therapy as a dangerous complication in patients with multiple severe stenoses in the cerebral arteries.

Vertical gaze palsy is rarely a neurological symptom, although it has been observed in some cases. Here, we report the case of a patient presenting with complete upward and downward gaze palsy. In this case, a small lesion in the left rostral midbrain was observed on diffusion-weighted magnetic resonance (MR) images, and the lesion was considered to cause the ocular symptom. We consider that vertical gaze palsy is an important clue to an accurate topical diagnosis of a brain lesion.

Some stroke patients with the acute aortic dissection receiving thrombolysis treatment resulted in fatalities. Thus, the concurrent acute aortic dissection is the contraindication for the intravenous recombinant tissue-type plasminogen activator. However, the safety and the effectiveness of the intravenous recombinant tissue-type plasminogen activator therapy are not known in patients with stroke some days after acute aortic dissection treatment. Here, we first report a case of a man with a cardioembolism due to the nonvalvular atrial fibrillation, who received the intravenous recombinant tissue-type plasminogen activator therapy 117 days after the traumatic Stanford type A acute aortic dissection operation. Without the intravenous recombinant tissue-type plasminogen activator therapy, the prognosis was expected to be miserable. However, the outcome was good with no complication owing to the intravenous recombinant tissue-type plasminogen activator therapy. Our case suggests the effectiveness and the safety of the intravenous recombinant tissue-type plasminogen activator therapy to the ischemic stroke some days after acute aortic dissection treatment.

Although foam sclerotherapy to varicose veins is now a popular treatment because of its high efficacy and safety, some neurologic complications have recently been reported. Presently, the effectiveness and safety of intravenous recombinant tissue-type plasminogen activator therapy to stroke following foam sclerotherapy remain unclear. Here, we report the case of a 68-year-old woman whose ischemic symptoms following foam sclerotherapy were treated by intravenous recombinant tissue-type plasminogen activator. After she was admitted, the venous thrombosis in her right soleus vein and a patent foramen ovale causing the right-to-left shunt were revealed. Thus, we diagnosed the ischemic symptoms were due to paradoxical embolism following foam sclerotherapy. After intravenous recombinant tissue-type plasminogen activator therapy, there was no complication and the outcome was good. Our case suggests the effectiveness and the safety of intravenous recombinant tissue-type plasminogen activator therapy to paradoxical embolism following foam sclerotherapy.

Cytoplasmic protein aggregates are one of the pathological hallmarks of neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). Several RNA-binding proteins have been identified as components of inclusion bodies. Developmentally regulated RNA-binding protein 1 (Drb1)/RNA-binding motif protein 45 is an RNA-binding protein that was recently described as a component in ALS- and FTLD-related inclusion bodies. However, the molecular mechanism underlying cytoplasmic Drb1 aggregation remains unclear. Here, using an in vitro cellular model, we demonstrated that Drb1 co-localizes with cytoplasmic aggregates mediated by TAR DNA-binding protein 43, a major component of ALS and FTLD-related inclusion bodies. We also defined the domains involved in the subcellular localization of Drb1 to clarify the role of Drb1 in the formation of cytoplasmic aggregates in ALS and FTLD. Drb1 predominantly localized in the nucleus via a classical nuclear localization signal in its carboxyl terminus and is a shuttling protein between the nucleus and cytoplasm. Furthermore, we identify a double leucine motif serving as a nuclear export signal. The Drb1 mutant, presenting mutations in both nuclear localization signal and nuclear export signal, is prone to aggregate in the cytoplasm. The mutant Drb1-induced cytoplasmic aggregates not only recruit TAR DNA-binding protein 43 but also decrease the mitochondrial membrane potential. Taken together, these results indicate that perturbation of Drb1 nuclear-cytoplasmic trafficking induces toxic cytoplasmic aggregates, suggesting that mislocalization of Drb1 is involved in the cause of cytotoxicity in neuronal cells.