Pembrolizumab-induced Myopathy with Anti-striated Muscle Antibodies Successfully Treated by Plasma Exchange

A 70-year-old woman with advanced endometrial cancer developed right ptosis and muscle weakness in the right quadriceps after pembrolizumab administration. Serum creatine kinase (CK) levels were elevated, and anti-striated muscle antibodies were positive. On magnetic resonance imaging, the right vastus lateral muscle showed an abnormal signal. She was diagnosed with pembrolizumab-induced myopathy. We initiated plasma exchange (PE), and the ptosis immediately resolved. We then introduced oral corticosteroids, which improved her muscle weakness. We were able to rapidly diagnose her with ocular symptoms and serum CK level elevation. The early initiation of PE might prevent the exacerbation of pembrolizumab-induced myopathy.

[Immune-Mediated Necrotizing Myopathy(IMNM)]

Immune-mediated necrotizing myopathy (IMNM) has recently been classified from polymyositis, and it clinically shows subacute progressive proximal dominant muscle weakness. Laboratory examinations show a great increase in serum creatine kinase and prominent necrotic muscle fibers without any pathological invasion of inflammatory cells. It is thought to be an autoimmune disease because SRP and HMGCR antibodies have been detected in many cases. These two antibodies affect the pathophysiology of IMNM. Immuno-modulating therapies have usually been induced. Moreover, intensive treatments are necessary in cases of corticosteroid resistant IMNM.

[Therapeutic Strategies for Idiopathic Inflammatory Myopathies]

Almost all types of idiopathic inflammatory myopathy (IIM) are treated by immune-modulating therapies. Corticosteroids, such as prednisolone and methylprednisolone, are used as first-line therapy for IIM. When the symptoms cannot be sufficiently improved, immunosuppressive agents, such as azathioprine, methotrexate, or tacrolimus, should be administered approximately two weeks after starting corticosteroid therapy. Moreover, intravenous immunoglobulin is recommended for severe cases at the same time as starting immunosuppressive agents. If these therapies do not improve symptoms, biologics, such as rituximab, should be introduced. Once IIM is controlled with immuno-modulating therapies, the drugs should be gradually tapered to avoid exacerbating the symptoms.

[Treatment of Dermatomyositis and Immune-Mediated Necrotizing Myopathy with Poor Muscle Recovery with Steroids and IVIg: Therapeutic Strategies for Refractory Inflammatory Myositis]

The majority of inflammatory myositis cases can be cured by immunomodulatory therapies. We recently observed that the phenotype and response to therapies differed according to myositis-specific autoantibodies; therefore, it is essential to select a suitable therapy after thoroughly evaluating the autoantibody, clinical severity, and complications. In some cases, the symptoms can be controlled by steroid monotherapy, but some cases exhibit steroid resistance and require other therapies. We recommend intensive treatment involving the addition of immunosuppressive agents in the early stage and repeated intravenous administration of immunoglobulin therapy in cases of refractory myositis, such as immune-mediated necrotizing myopathy.

Successful treatment of ischemic stroke associated with brachiocephalic artery stenosis using alteplase

Introduction: Brachiocephalic artery stenosis rarely causes right hemispheric infarction with associated left hemiparesis. To date, there have been no reported cases of stroke associated with brachiocephalic artery stenosis that were successfully treated with recombinant tissue-type plasminogen activator (rt-PA), alteplase.

Case Report: An 80-year-old woman presented with left hemiparesis. Brain computed tomography showed no hemorrhage, and computed tomography angiography demonstrated brachiocephalic artery stenosis. Alteplase was administered based on a diagnosis of ischemic stroke. Brain magnetic resonance imaging showed multiple acute infarctions. Thereafter, the blood pressure of the right arm was found to be lower than that of the left arm. The patient’s neurological deficits gradually improved; she was eventually able to walk again and was thus discharged home.

Conclusion: While the combination of left hemiparesis and a decrease in blood pressure in the right arm are well known in patients with stroke associated with Stanford type A aortic dissections, it may also occur in patients with stroke due to brachiocephalic artery stenosis. Unlike stroke associated with Stanford type A aortic dissections, stroke due to brachiocephalic artery stenosis may be treated with alteplase.

Distribution of Deep Gray Matter Lesions on Magnetic Resonance Imaging in Lymphomatosis Cerebri

We herein report the distribution of gray matter lesions on magnetic resonance imaging (MRI) in two patients with lymphomatosis cerebri (LC). In our patients, the fluid-attenuated inversion recovery sequence of brain MRI demonstrated a bilateral and diffuse high signal intensity, not only in the white matter but also in the thalamus, globus pallidus, putamen, and hippocampus. Among the deep gray matter, the caudate head and putamen (striatum) were relatively spared when compared with the globus pallidus, thalamus, and hippocampus. Interestingly, we found seven previous reports of similar MRI findings, with relative sparing of the striatum, in patients with LC. This finding may be characteristic of LC and help facilitate its diagnosis. Further investigations of a larger number of LC patients are necessary to confirm these findings.

[Immune-Mediated Necrotizing Myopathy: IMNM]

Immune-mediated necrotizing myopathy (IMNM) is a heterogeneous disease that presents with subacute progressive proximal dominant muscle weakness clinically and prominent necrotic muscle fibers without invasion of inflammatory cells pathologically. IMNM is a disease that exclusively affects skeletal muscles, so the serum creatine kinase level usually increases prominently. It is thought to be an autoimmune disease because of the presence of two autoantibodies, anti-SRP and anti-HMGCR. Because muscle involvement is more severe than that in other forms of myositis, its functional prognosis is worse. Several immune-modifying therapies can improve the symptoms; therefore, intensive treatments should be started soon after diagnosis with IMNM.

Treatment consensus for management of polymyositis and dermatomyositis among rheumatologists, neurologists and dermatologists

Although rheumatologists, neurologists and dermatologists see patients with polymyositis (PM) and dermatomyositis (DM), their management appears to vary depending on the physician's specialty. The aim of the present study was to establish the treatment consensus among specialists of the three fields to standardize the patient care. We formed a research team supported by a grant from the Ministry of Health, Labor and Welfare, Japan. Clinical questions (CQ) on the management of PM and DM were raised. A published work search on CQ was performed primarily using PubMed. Using the nominal group technique, qualified studies and results in the published work were evaluated and discussed to reach consensus recommendations. They were sent out to the Japan College of Rheumatology, Japanese Society of Neurology and Japanese Dermatological Association for their approval. We reached a consensus in 23 CQ and made recommendations and a decision tree for management was proposed. They were officially approved by the three scientific societies. In conclusion, a multidisciplinary treatment consensus for the management of PM and DM was established for the first time.

Retrobulbar optic neuropathy associated with sphenoid sinus mucormycosis

Because fungi usually spread from the paranasal sinuses to the orbital apex in invasive fungal sinusitis (IFS), IFS often presents as an orbital apex syndrome (OAS) characterized by dysfunction of cranial nerves II, III, IV, V1, and VI. We report a case of sphenoid sinus mucormycosis that presented as isolated retrobulbar optic neuropathy. A 94-year-old woman presented with acute blindness in the right eye. Examination revealed the absence of light perception and pupillary reflex in the right eye. Head MRI showed a mass in the right sphenoid sinus, which was contiguous with the right optic nerve. She underwent endoscopic surgery, and a histopathological diagnosis of mucormycosis was established. Treatment with intravenous liposomal amphotericin B reduced the size of the mass. She has survived for more than 1 year without recurrence. Clinicians should consider that IFS can present as isolated retrobulbar optic neuropathy.

Acute pancreatitis is a very rare comorbidity of acute ischemic stroke

Background: Although acute pancreatitis is listed among the exclusion criteria for the administration of recombinant tissue plasminogen activator according to the Japanese Guideline for the Management of Stroke, the co-occurrence of acute pancreatitis and acute ischemic stroke has not been investigated. The present study aimed to assess the incidence rate of acute pancreatitis in patients with acute ischemic stroke.

Methods: This study consecutively enrolled all patients with ischemic stroke admitted to the Department of Neurology, JA Toride Medical Center between April 2014 and March 2016. Diagnosis of acute pancreatitis was made according to the revised Atlanta Classification of Acute Pancreatitis. We retrospectively analyzed serum amylase activity and the frequency of acute pancreatitis as a comorbidity of ischemic stroke.

Results: A total of 411 ischemic stroke patients were included. Serum amylase activity was measured for 364 patients, 27 of whom presented with amylase activity exceeding the upper limit of normal. In two patients with serum amylase activity greater than three times-fold the upper limit of normal, computed tomography or transabdominal ultrasonography showed no characteristic findings of acute pancreatitis. No patient in the cohort met the diagnostic criteria for acute pancreatitis.

Conclusions: Acute pancreatitis is a very rare comorbidity of acute ischemic stroke.

Bilateral Frontal Lobe Vasogenic Edema Resulting from Hypertrophic Pachymeningitis due to Granulomatosis with Polyangiitis

A 61-year-old woman presented with a 1-month history of decreased activities of daily living. Magnetic resonance imaging revealed abnormal intensities of the bilateral frontal lobes and enhancement of the thickened dura matter. A biopsy of the dura mater revealed multinucleated giant cells. She had sinusitis and hematuria; she was diagnosed with granulomatosis with polyangiitis. Hypertrophic pachymeningitis (HPM) was considered to have interrupted the venous flow and caused vasogenic edema. Bilateral frontal lobe edema resulting from HPM due to granulomatosis with polyangiitis has not been reported. A biopsy and examination for other organ complications were useful for the diagnosis and treatment of our patient.

Pneumococcal Pyomyositis of the Neck Muscles

High fever, severe neck pain and neck stiffness can result from meningitis. We report a case of pneumococcal pyomyositis of the neck muscles. A 72-year-old man developed high fever and severe neck pain. His chief complaint mimicked bacterial meningitis. Although his condition was initially suspected to be bacterial meningitis, his cerebrospinal fluid did not show pleocytosis. MRI showed areas of high intensity in the posterior deep neck muscles on short tau inversion recovery (STIR) sequences and gadolinium-enhanced T1-weighted images. Pneumococcal myositis should therefore be included in the differential diagnosis of severe neck pain with fever.

Disappearance of the Hummingbird Sign after Shunt Surgery in a Case of Idiopathic Normal Pressure Hydrocephalus

A 79-year-old man presented with a slowly progressive gait disturbance. Brain MRI demonstrated ventriculomegaly and the hummingbird sign. A lumbar puncture showed no abnormalities of the cerebrospinal fluid. The improvement of the gait disturbance after the ventriculoperitoneal shunt led to a diagnosis of idiopathic normal pressure hydrocephalus. Interestingly, postoperative brain MRI demonstrated the disappearance of not only ventriculomegaly, but also the hummingbird sign. The disappearance of the hummingbird sign suggests that an increase in the cerebrospinal fluid in the lateral and third ventricles could cause the compression of the superior surface of the midbrain tegmentum, which manifests as the hummingbird sign.

Epidemiologic analysis of the clinical features of Japanese patients with polymyositis and dermatomyositis

OBJECTIVES

This study aimed to investigate the clinical characteristics of polymyositis/dermatomyositis (PM/DM) in Japan by analyzing data from the nationwide registration system.

METHODS

The data of the registration system in 2009 were analyzed to investigate patient numbers, sex, clinical symptoms, therapies, complications, and prognosis of PM/DM.

RESULTS

The total number of PM/DM cases was approximately 17,000, and the female/male sex ratio was 2.7:1. Almost all patients improved as a result of therapy, but many suffered from sequelae such as muscle weakness.

CONCLUSIONS

The results characterize significant aspects of Japanese PM/DM patients. However, a further prospective survey is required to clarify the true epidemiology and natural history of PM/DM.

Significance of Development and Reversion of Collaterals on MRI in Early Neurologic Improvement and Long-Term Functional Outcome after Intravenous Thrombolysis for Ischemic Stroke

BACKGROUND AND PURPOSE

Predicting response to rtPA is essential in the era of endovascular therapy for stroke. The purpose of this study was to elucidate prognostic factors of early neurologic improvement and long-term outcome with respect to the development and reversion of leptomeningeal collaterals in recanalization therapy after acute ischemic stroke.

MATERIALS AND METHODS

We analyzed consecutive patients with proximal MCA occlusion treated with rtPA from 2007 to 2012 at 2 hospital stroke centers. All patients routinely underwent brain MR imaging before rtPA. To assess the reversion of collateral signs, we included patients who underwent follow-up MR imaging. We assessed the development and reversion of collaterals by using a combination of 2 MR imaging collateral markers, the hyperintense vessel sign and the posterior cerebral artery laterality sign. Early neurologic improvement was defined as a decrease in the NIHSS score of ≥10 or a score of ≤2 at 24 hours of treatment.

RESULTS

Early neurologic improvement was observed in 22 of 48 eligible patients. The development of collaterals at arrival (15/22 versus 9/26, P = .042) was significantly associated with early neurologic improvement. Multivariate analysis adjusting for other variables showed that the development of collaterals at arrival (OR, 4.82; 95% CI, 1.34-19.98; P = .015) was independently associated with early neurologic improvement. Reversion of collaterals was significantly associated with successful recanalization (P < .001), and multivariate analysis showed that the reversion of collaterals was an independent prognostic factor of long-term functional outcome (OR, 5.07; 95% CI, 1.38-22.09; P = .013).

CONCLUSIONS

Our results indicate that the development of leptomeningeal collaterals plays a crucial role in achieving early neurologic improvement, and reversion of collaterals predicts a favorable outcome via arterial recanalization after rtPA treatment for acute stroke.

Immune-mediated neuropathy with Epstein-Barr virus-positive T-cell lymphoproliferative disease

A 47-year-old man with Epstein-Barr virus (EBV)-positive T/NK- cell lymphoproliferative disease (EBV-T/NK-LPD) developed acute-onset weakness. A nerve conduction study showed a conduction block in both the proximal and most distal segments. Although the patient's neuropathy transiently responded to intravenous immunoglobulin, it was progressive for at least 25 days until the start of prednisolone (PSL) administration, after which it remarkably improved. The neuropathy further improved after allogeneic bone marrow transplantation (BMT). The present patient's clinical course is not consistent with that of typical Guillain-Barré syndrome. This case suggests that EBV-T/NK-LPD can cause progressive immune-mediated neuropathy as a result of chronic EBV antigen presentation and can be treated with PSL and BMT.

Sphenoid Sinusitis Complicated by Pneumococcal Meningitis and an Infectious Aneurysm in the Intracavernous Carotid Artery

A 61-year-old Japanese woman presented with a headache and appetite loss lasting for nine days and was admitted to our hospital, where she was diagnosed with pneumococcal meningitis associated with acute sphenoid sinusitis. While the administration of meropenem and dexamethasone ameliorated the meningitis, right third and sixth nerve palsy suddenly developed 10 days after admission. CT angiography subsequently demonstrated an aneurysm in the cavernous portion of the right internal carotid artery. This is the first reported case of sphenoid sinusitis simultaneously complicated by both pneumococcal meningitis and an infectious aneurysm in the intracavernous carotid artery.

Right hand predominant constructional apraxia due to right hemisphere infarction without corpus callosum lesions

A 74-year-old right-handed woman without cognitive impairment suddenly developed nonfluent aphasia. Brain MRI showed acute infarction in the right frontal lobe and insula without involvement of the corpus callosum. A neurological examination demonstrated not only transcortical motor aphasia, but also ideomotor apraxia and right hand predominant constructional apraxia (CA). To date, right hand predominant CA has only been reported in patients with corpus callosum lesions. The right hand predominant CA observed in our patient may be associated with the failure to transfer information on the spatial structure from the right hemisphere to the motor cortex of the left hemisphere.

Prevalence and incidence of polymyositis and dermatomyositis in Japan

OBJECTIVES

To estimate the number of patients with polymyositis/dermatomyositis (PM/DM) in Japan and the prevalence rate and incidence rate of the disease.

METHODS

The electronic database in the nationwide registration system on intractable diseases from 2003 to 2010 was utilized to identify the number of prevalent and incident cases of PM/DM. The electronic data entry rate was used to establish the total number of registered cases.

RESULTS

The estimated total number of patients with PM/DM and the prevalence rate in Japan in 2010 were 17,000 and 13.2 per 100,000 population, respectively. The prevalence of PM/DM ranged from 10 to 13 per 100,000 population with a trend toward increasing over time. The incidence of PM/DM was estimated within the range 10-13 per 1,000,000 person-years, except for 2003.

CONCLUSIONS

We report the prevalence and incidence of PM/DM recently in Japan for the first time at the nationwide population level. Because the prevalence seems to be increasing recently, continued monitoring of these epidemiologic features is required.

Thalamic hypoperfusion in early stage of progressive supranuclear palsy (Richardson's syndrome): report of an autopsy-confirmed case

Progressive supranuclear palsy-Richardson's syndrome (PSP-RS) is a neurodegenerative disease characterized by postural instability and vertical gaze palsy, but the clinical diagnosis of PSP-RS is often difficult in the early stage of the disease. A 64-year-old male experienced frequent falls, followed by dysarthria and dysphagia. Neurological examination at age 64 demonstrated vertical gaze palsy, dysarthria, dysphagia, and retropulsion. At that time, while brain MRI demonstrated no apparent abnormalities, SPECT showed the reduction of the cerebral blood flow in the thalamus as well as the medial frontal lobe cortices. The patient was diagnosed with probable PSP-RS, and died at age 70. On postmortem examination, there were abundant tuft-shaped astrocytes, neurofibrillary tangles, coiled bodies, and argyrophilic threads in the brain, establishing the diagnosis of PSP-RS. Our definite PSP-RS case suggests that thalamic hypoperfusion may provide helpful evidence to support a diagnosis of PSP-RS in the early stage of the disease.

Evaluation of the efficacy of pramipexole for treating levodopa-induced dyskinesia in patients with Parkinson's disease

OBJECTIVE

The long-term use of levodopa to treat Parkinson's disease (PD) is often limited by the development of motor complications (e.g., levodopa-induced dyskinesia, LID). We hypothesized that a non-ergot dopamine agonist with strong affinity for D3) dopamine receptors (pramipexole) may improve LID in patients taking an ergot D1/D2 dopamine agonist.

METHODS

Patients with PD and LID being treated with levodopa in addition to an ergot dopamine agonist were randomized to either a group in which pramipexole was added to current medications or a group in which the ergot dopamine agonist was switched to pramipexole. Dyskinesia was evaluated using Core Assessment Program for Surgical Interventional Therapies scores. The unified Parkinson's disease rating scale scores, modified Hoehn and Yahr stages (at 'on' time), Parkinson's disease questionnaire-39 scores and clinical global impression-improvement scores were also used for evaluation.

RESULTS

At 24 weeks, pramipexole alleviated LID with more efficiency in the switch group.

CONCLUSION

Pramipexole may be a therapeutic option for treating LID because its effects on D3 dopamine receptors may balance the D1 dopamine receptor supersensitivity associated with LID.

Failure of mefloquine therapy in progressive multifocal leukoencephalopathy: report of two Japanese patients without human immunodeficiency virus infection

Although progressive multifocal leukoencephalopathy (PML) cases showing responses to mefloquine therapy have been reported, the efficacy of mefloquine for PML remains unclear. We report on the failure of mefloquine therapy in two Japanese patients with PML unrelated to human immunodeficiency virus. One of the patients was a 47-year-old male who had been treated with chemotherapy for Waldenström macroglobulinemia, and the other was an 81-year-old male with idiopathic CD4(+) lymphocytopenia. Diagnosis of PML was established based on MRI findings and increased JC virus DNA in the cerebrospinal fluid in both patients. Mefloquine was initiated about 5 months and 2 months after the onset of PML, respectively. During mefloquine therapy, clinical and radiological progression was observed, and JC virus DNA in the cerebrospinal fluid was increased in both patients. Both patients died about 4 months and 2 months after initiation of mefloquine, respectively. Further studies are necessary to clarify the differences between mefloquine responders and non-responders in PML.

Age at onset and gender distribution of systemic lupus erythematosus, polymyositis/dermatomyositis, and systemic sclerosis in Japan

OBJECTIVES

The aim of this study was to describe age, gender distribution, and age at onset of systemic lupus erythematosus (SLE), polymyositis/dermatomyositis (PM/DM), and systemic sclerosis (SSc) in Japan.

METHODS

We used epidemiological information on 21,405, 6,327, and 10,058 patients with SLE, PM/DM, and SSc, respectively, in a Japanese nationwide registration database of patients with intractable diseases.

RESULTS

All three diseases occur predominantly in women, with the female-to-male ratio being 8.2:1, 2.6:1, and 7.7:1 for SLE, PM/DM, and SSc, respectively. The most susceptible age for SLE is 15-44 and 20-39 years for males and females, respectively. For PM/DM it is 45-64 and 40-64 years and for SSc, 50-69 and 40-59 for men and women, respectively.

CONCLUSIONS

The basic descriptive epidemiological characteristics of SLE, PM/DM, and SSc in Japan, such as gender distribution, present age, and age at onset, were surveyed nationwide for fiscal 2007. It was found that these characteristics were similar to those in Western populations. Our finding provides new information on the natural history of disease development.

Heterozygous UDP-GlcNAc 2-epimerase and N-acetylmannosamine kinase domain mutations in the GNE gene result in a less severe GNE myopathy phenotype compared to homozygous N-acetylmannosamine kinase domain mutations

BACKGROUND

Glucosamine (UDP-N-acetyl)-2-epimerase/N-acetylmannosamine kinase (GNE) myopathy, also called distal myopathy with rimmed vacuoles (DMRV) or hereditary inclusion body myopathy (HIBM), is a rare, progressive autosomal recessive disorder caused by mutations in the GNE gene. Here, we examined the relationship between genotype and clinical phenotype in participants with GNE myopathy.

METHODS

Participants with GNE myopathy were asked to complete a questionnaire regarding medical history and current symptoms.

RESULTS

A total of 71 participants with genetically confirmed GNE myopathy (27 males and 44 females; mean age, 43.1±13.0 (mean±SD) years) completed the questionnaire. Initial symptoms (e.g., foot drop and lower limb weakness) appeared at a mean age of 24.8±8.3 years. Among the 71 participants, 11 (15.5%) had the ability to walk, with a median time to loss of ambulation of 17.0±2.1 years after disease onset. Participants with a homozygous mutation (p.V572L) in the N-acetylmannosamine kinase domain (KD/KD participants) had an earlier disease onset compared to compound heterozygous participants with mutations in the uridine diphosphate-N-acetylglucosamine (UDP-GlcNAc) 2-epimerase and N-acetylmannosamine kinase domains (ED/KD participants; 26.3±7.3 vs. 21.2±11.1 years, respectively). KD/KD participants were more frequently non-ambulatory compared to ED/KD participants at the time of survey (80% vs. 50%). Data were verified using medical records available from 17 outpatient participants.

CONCLUSIONS

Homozygous KD/KD participants exhibited a more severe phenotype compared to heterozygous ED/KD participants.

Musculoskeletal symptoms and neurological investigations in adrenocortical insufficiency: a case report and literature review

OBJECTIVES

Various forms of adrenocortical insufficiency can cause musculoskeletal symptoms such as muscle pain, tautness of the limbs, arthralgia, and flexion contractures. However, the findings of neurological investigations are inconclusive and have not been well summarized.

METHODS

We report the case of a 61-year-old man with isolated adrenocorticotropic hormone deficiency who presented with musculoskeletal symptoms, including flexion contractures. We performed three neurological investigations: nerve conduction studies, electromyography, and muscle biopsy analysis. Further, we reviewed reports of 16 patients with various forms of adrenocortical insufficiency and musculoskeletal symptoms by considering the findings of these three investigations.

RESULTS

From the literature review, we found that (a) analysis of muscle biopsy is the most sensitive technique, followed by electromyography and then nerve conduction studies; and (b) the longer the duration of the musculoskeletal symptoms, the greater the incidence of abnormal findings with all three techniques.

CONCLUSIONS

Physicians may prioritize neurological investigations, depending on these findings.

Depletion of vitamin E increases amyloid beta accumulation by decreasing its clearances from brain and blood in a mouse model of Alzheimer disease

Increased oxidative damage is a prominent and early feature in Alzheimer disease. We previously crossed Alzheimer disease transgenic (APPsw) model mice with alpha-tocopherol transfer protein knock-out (Ttpa(-/-)) mice in which lipid peroxidation in the brain was significantly increased. The resulting double-mutant (Ttpa(-/-)APPsw) mice showed increased amyloid beta (Abeta) deposits in the brain, which was ameliorated with alpha-tocopherol supplementation. To investigate the mechanism of the increased Abeta accumulation, we here studied generation, degradation, aggregation, and efflux of Abeta in the mice. The clearance of intracerebral-microinjected (125)I-Abeta(1-40) from brain was decreased in Ttpa(-/-) mice to be compared with wild-type mice, whereas the generation of Abeta was not increased in Ttpa(-/-)APPsw mice. The activity of an Abeta-degrading enzyme, neprilysin, did not decrease, but the expression level of insulin-degrading enzyme was markedly decreased in Ttpa(-/-) mouse brain. In contrast, Abeta aggregation was accelerated in Ttpa(-/-) mouse brains compared with wild-type brains, and well known molecules involved in Abeta transport from brain to blood, low density lipoprotein receptor-related protein-1 (LRP-1) and p-glycoprotein, were up-regulated in the small vascular fraction of Ttpa(-/-) mouse brains. Moreover, the disappearance of intravenously administered (125)I-Abeta(1-40) was decreased in Ttpa(-/-) mice with reduced translocation of LRP-1 in the hepatocytes. These results suggest that lipid peroxidation due to depletion of alpha-tocopherol impairs Abeta clearances from the brain and from the blood, possibly causing increased Abeta accumulation in Ttpa(-/-)APPsw mouse brain and plasma.

UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase in nuclei and rimmed vacuoles of muscle fibers in DMRV (distal myopathy with rimmed vacuoles)

BACKGROUND

UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase (GNE) is a key molecule in the pathogenesis of distal myopathy with rimmed vacuoles (DMRV) and hereditary inclusion body myopathy (HIBM) and almost all such patients have some mutations in GNE. However, subcellular localization of GNE and the mechanism of muscular damage have not been clarified.

METHODS

A rabbit polyclonal antibody for GNE was prepared. Immunohistochemistry was performed using anti-GNE and anti-nuclear protein antibodies. Western blotting with subcellular fractionated proteins was performed to determine subcellular localization of GNE. The sizes of myonuclei were quantified in muscle biopsies from patients with DMRV and amyotrophic lateral sclerosis (ALS).

RESULTS

In DMRV muscles, immunohistochemistry identified GNE in sarcoplasm and specifically in myonuclei and rimmed vacuoles (RV). Nuclear proteins were also found in RVs. Immunohistochemistry showed colocalization of GNE and emerin in C2C12 cells. Western blotting revealed the presence of GNE in nuclear fractions of human embryonic kidney (HEK) 293T cells. The mean size of myonuclei of DMRV was significantly larger than that of ALS.

CONCLUSION

GNE is present in myonuclei near nuclear membrane. Our results suggest that myonuclei are involved in RV formation in DMRV, and that mutant GNE in myonuclei seems to play some role in this process.

Early clinical signs and imaging findings in Gerstmann-Sträussler-Scheinker syndrome (Pro102Leu)

OBJECTIVE

To determine the clinical and radiologic features of Gerstmann-Sträussler-Scheinker syndrome caused by Pro102Leu mutation in PRNP (GSS102).

METHODS

The authors report 11 patients (nine families) with clinically and radiologically diagnosed GSS102.

RESULTS

All patients showed mild gait disturbance, dysesthesia and hyporeflexia of the lower legs, and truncal ataxia, and 9 of 11 patients showed proximal leg muscle weakness during the early stage of the disease. Dementia was not a main symptom during the early stage. Brain MRI and EEG abnormalities were not prominent initially. SPECT (N-isopropyl-p-[(123)I]iodoamphetamine) analyzed by the three-dimensional stereotactic surface projection (SSP) method detected abnormalities in five patients early during the course of the illness. SPECT findings showed diffusely decreased cerebral blood flow, demonstrated by a mosaic pattern, with the lowest perfusion noted in the occipital lobes. In contrast, blood flow to the cerebellum was preserved. These studies suggested sites of pathology in GSS102, with the main lesions probably located in the cerebrum and the spinal cord (posterior horn and spinocerebellar tract) instead of the cerebellum.

CONCLUSIONS

Key features for early diagnosis of Gerstmann-Sträussler-Scheinker syndrome caused by Pro102Leu mutation in PRNP (GSS102) are truncal ataxia, dysesthesia and hyporeflexia of the lower legs, and mild dysarthria. Normal cerebellar MRI and abnormal cerebral SPECT findings are characters of early GSS102.

IgM-containing fraction suppressed voltage-gated potassium channels in acquired neuromyotonia

OBJECTIVES

Acquired neuromyotonia (ANM) is an autoimmune disorder caused by antibodies to voltage-gated potassium channels (VGKC). Previously, we reported a patient with immunoglobulin M (IgM), instead of immunoglobulin G (IgG), anti-VGKC antibody. The purpose of this study was to determine the function of IgM-containing fraction in ANM patients.

MATERIALS AND METHODS

We determined whether anti-VGKC antibodies in the IgG or IgM-containing fractions suppressed outward potassium current (OKC) using the patch clamp method in three patients with ANM. Whole sera from all patients suppressed OKCs.

RESULT

Only the purified IgG, not the IgM-containing fractions from two patients suppressed VGKCs, whereas in a patient with IgM anti-VGKC antibody, only the IgM-containing fractions, not the IgG-containing fractions suppressed VGKCs.

CONCLUSION

Anti-VGKC antibodies belonging to the IgM subclass should be determined in seronegative ANM patients.

Evaluation of cerebral dyschromatopsia using color afterimage

Cerebral dyschromatopsia is traditionally evaluated by color discrimination tests such as the Farnsworth-Maunsell 100 Hue Test. These tests are also used to evaluate color-perception deficits caused by eye disease, and they do not tell us whether color perception is impaired in the eye or in the brain. Here, we used color afterimage to isolate color-perception deficits in the brain from those in the eyes, in a patient with cerebral dyschromatopsia. The results showed that the patient perceived color afterimage of yellow and blue with abnormal duration and chromaticity. On the other hand, the patient performed normally on the Farnsworth-Maunsell 100 Hue Test. We conclude that the color afterimage test would be useful to evaluate color perception in the brain.

An autosomal dominant cerebellar ataxia linked to chromosome 16q22.1 is associated with a single-nucleotide substitution in the 5' untranslated region of the gene encoding a protein with spectrin repeat and Rho guanine-nucleotide exchange-factor domains

Autosomal dominant cerebellar ataxia (ADCA) is a group of heterogeneous neurodegenerative disorders. By positional cloning, we have identified the gene strongly associated with a form of degenerative ataxia (chromosome 16q22.1-linked ADCA) that clinically shows progressive pure cerebellar ataxia. Detailed examination by use of audiogram suggested that sensorineural hearing impairment may be associated with ataxia in our families. After restricting the candidate region in chromosome 16q22.1 by haplotype analysis, we found that all patients from 52 unrelated Japanese families harbor a heterozygous C-->T single-nucleotide substitution, 16 nt upstream of the putative translation initiation site of the gene for a hypothetical protein DKFZP434I216, which we have called "puratrophin-1" (Purkinje cell atrophy associated protein-1). The full-length puratrophin-1 mRNA had an open reading frame of 3,576 nt, predicted to contain important domains, including the spectrin repeat and the guanine-nucleotide exchange factor (GEF) for Rho GTPases, followed by the Dbl-homologous domain, which indicates the role of puratrophin-1 in intracellular signaling and actin dynamics at the Golgi apparatus. Puratrophin-1--normally expressed in a wide range of cells, including epithelial hair cells in the cochlea--was aggregated in Purkinje cells of the chromosome 16q22.1-linked ADCA brains. Consistent with the protein prediction data of puratrophin-1, the Golgi-apparatus membrane protein and spectrin also formed aggregates in Purkinje cells. The present study highlights the importance of the 5' untranslated region (UTR) in identification of genes of human disease, suggests that a single-nucleotide substitution in the 5' UTR could be associated with protein aggregation, and indicates that the GEF protein is associated with cerebellar degeneration in humans.

Somatosensory-evoked cortical potential during attacks of paroxysmal dysesthesia in multiple sclerosis

Paroxysmal dysesthesia is considered to be one of the characteristic symptoms of multiple sclerosis (MS), but the lesion responsible and the pathophysiology of this dysesthesia are not known. We report the interesting finding of somatosensory-evoked potentials (SEPs) in a patient with MS during a paroxysmal dysesthesia attack.

Distal myopathy with rimmed vacuoles (DMRV): new GNE mutations and splice variant

Study of the UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase gene (GNE) revealed that almost all cases of distal myopathy with rimmed vacuoles were caused by GNE mutations. Seven new mutations were identified, including M712T, which is the most common mutation in Jewish hereditary inclusion body myopathy. In addition, a splice-variant characteristic of the skeletal muscle was found, whereas the difference of the expression level between GNE-mutated and -nonmutated patients was not apparent.

A Japanese patient with distal myopathy with rimmed vacuoles: missense mutations in the epimerase domain of the UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase (GNE) gene accompanied by hyposialylation of skeletal muscle glycoproteins

Hereditary inclusion body myopathy and distal myopathy with rimmed vacuoles are both caused by mutations of the UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase (GNE) gene. Here we report a Japanese patient with compound heterozygous missense mutations in the epimerase domain of GNE gene, 89 G to C and 578 A to T. Biochemical analysis demonstrated decreased reactivity of skeletal muscle glycoproteins with the lectins recognizing sialic acid residues. The results suggest that hyposialylation of glycoproteins may be involved in the pathogenesis of muscle dysfunction in this patient.

Physical map and haplotype analysis of 16q-linked autosomal dominant cerebellar ataxia (ADCA) type III in Japan

Autosomal dominant cerebellar ataxia (ADCA) is a group of heterogeneous neurodegenerative disorders. We previously mapped a gene locus for ADCA with pure cerebellar syndrome (ADCA type III) to a 3-cM region in chromosome 16q, and found a common haplotype among affected individuals. This region was exactly within the locus for another ADCA, spinocerebellar ataxia type 4 (SCA4). To identify the gene causing 16q-linked ADCA type III, we constructed a contig with 38 bacterial artificial chromosome clones between D16S3043 and D16S3095. The size of this contig was estimated to be 4.8 Mb. We found more than 500 nucleotide tandem repeats, including 9 CAG/CTG repeats in this candidate region, although none of the 94 tandem repeats analyzed were expanded in affected individuals. However, we found 11 new polymorphic markers, giving 22 markers spanning the candidate region. By typing these markers on eight Japanese families with ADCA type III, including two new families, we found that a common "founder" haplotype is seen in a more restricted 3.8-Mb region, spanning markers GGAA05 and D16S3095. We present here a newly refined critical interval of 16q-ADCA type III/SCA4. Data of 11 new DNA markers on 16q22.1 would also be useful for other research of genes mapped to this region.

Distal myopathy with rimmed vacuoles: novel mutations in the GNE gene

The authors present three novel missense mutations in the UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase (GNE) gene, the causative gene for hereditary inclusion body myopathy, in Japanese patients with distal myopathy with rimmed vacuoles. Seven out of nine patients had homozygous V572L mutation, one was a compound heterozygote with C303V and V572L mutations, and the remaining patient bore homozygous A631V mutation.

[Episodic ataxia type 2]

Episodic ataxia type 2 is an autosomal dominant paroxysmal cerebellar ataxia characterized by acetazolamide-responsive recurrent attacks with interictal nystagmus. This disease is caused by mutations (mainly truncating mutation) within the alpha1(A) subunit of P/Q type voltage-dependent calcium channel gene, CACNA1A. Further researches would establish the genotype/phenotype correlation and clarify the mechanism of this disorder.

Involvement of the spinal posterior horn in Gerstmann-Sträussler-Scheinker disease (PrP P102L)

OBJECTIVE

The authors studied the pathomechanisms of the characteristics associated with Gerstmann-Sträussler-Scheinker disease (GSS).

BACKGROUND

GSS, associated with a missense mutation at codon 102 of the prion protein (PrP) gene (GSS102), is a hereditary disorder that presents with progressive ataxia and dementia, and is characterized by the loss of deep tendon reflexes and painful dysesthesias of the legs in its early stage.

METHODS

The authors conducted immunohistochemical studies of the spinal cord and peripheral nervous system in one of two patients from a Japanese family with GSS102 in comparison with patients with GSS105.

RESULTS

The authors found intense PrP immunoreactivities mainly in the posterior horn of the spinal cord, but not in the dorsal root ganglia or peripheral nerves. In addition to PrP amyloid plaques, synaptic-type, fine granular PrP deposits were distributed in the spinal posterior horns. In contrast to the GSS102 patient, the spinal cords of the GSS105 patients showed no granular PrP deposits.

CONCLUSIONS

The PrP abnormalities in synaptic structures of the spinal posterior horn may cause synaptic dysfunction that leads to loss of deep tendon reflexes and painful dysesthesias in patients with GSS102.

Unmyelinated nerve fibers in sural nerve in pure autonomic failure

We examined sural nerve biopsy specimens from 7 patients with pure autonomic failure (PAF). The mean unmyelinated nerve fiber density in these patients was 40% less than in age-matched controls. Increased numbers of clusters of collagen pockets not containing unmyelinated axons were the most prominent finding in PAF. This appears to reflect recent dropout of a group of sympathetic efferents and suggests grouping of unmyelinated fibers by modality at the level of the sural nerve trunk.