Masashiro Sugawara

A novel de novo mutation in the desmin gene causes desmin myopathy with toxic aggregates

Objective: To determine the cause and pathogenic mechanisms of a 21-year-old patient’s cardioskeletal myopathy. The patient’s muscle atrophy and weakness began in distal parts of limbs; cardiac and facial muscles were later involved. Background: Desmin myopathy is a skeletal myopathy often associated with cardiomyopathy, caused by mutations in the desmin gene and characterized by desmin accumulation in affected muscle fibers, a leading marker of myofibrillar myopathies. Two kinds of deletions and seven missense mutations in the desmin gene have been identified. Methods: Clinical examination, electron microscopy of muscle tissue, two-dimensional gel electrophoresis, DNA sequencing, restriction enzyme analysis, and gene transfection were performed. Results: Electron microscopy showed disruption of sarcomeres at Z discs and electron-dense aggregates in biopsied skeletal and heart muscle. Two-dimensional gel electrophoresis of the patient’s skeletal muscle proteins showed massive accumulation of desmin. The authors identified a novel desmin mutation, L385P in one allele in the carboxyl end of the rod domain 2B in the patient’s leukocytes and skeletal muscle; neither parent had the mutation. Serologic study and DNA markers confirmed the de novo mutation. A peptide harboring desmin rod domains 2A and 2B with L385P tagged with green fluorescent protein induced cytoplasmic aggregates, nuclear DNA condensation, and cell death. Conclusions: A novel de novo mutation, L385P, causes desmin myopathy. An expression study indicated the toxic effect of the L385P mutation.

Clinicopathological features of neuropathy associated with lymphoma

Lymphoma causes various neurological manifestations that might affect any part of the nervous system and occur at any stage of the disease. The peripheral nervous system is one of the major constituents of the neurological involvement of lymphoma. In this study we characterized the clinical, electrophysiological and histopathological features of 32 patients with neuropathy associated with non-Hodgkins lymphoma that were unrelated to complications resulting from treatment for lymphoma. Nine patients had pathologically-proven neurolymphomatosis with direct invasion of lymphoma cells into the peripheral nervous system. These patients showed lymphomatous cell invasion that was more prominent in the proximal portions of the nerve trunk and that induced demyelination without macrophage invasion and subsequent axonal degeneration in the portion distal from the demyelination site. Six other patients were also considered to have neurolymphomatosis because these patients showed positive signals along the peripheral nerve on fluorodeoxyglucose positron emission tomography imaging. Spontaneous pain can significantly disrupt daily activities, as frequently reported in patients diagnosed with neurolymphomatosis. In contrast, five patients were considered to have paraneoplastic neuropathy because primary peripheral nerve lesions were observed without the invasion of lymphomatous cells, with three patients showing features compatible with chronic inflammatory demyelinating polyneuropathy, one patient showing sensory ganglionopathy, and one patient showing vasculitic neuropathy. Of the other 12 patients, 10 presented with multiple mononeuropathies. These patients showed clinical and electrophysiological features similar to those of neurolymphomatosis rather than paraneoplastic neuropathy. Electrophysiological findings suggestive of demyelination were frequently observed, even in patients with neurolymphomatosis. Eleven of the 32 patients, including five patients with neurolymphomatosis, fulfilled the European Federation of Neurological Societies/Peripheral Nerve Society electrodiagnostic criteria of definite chronic inflammatory demyelinating polyneuropathy. Some of these patients, even those with neurolymphomatosis, responded initially to immunomodulatory treatments, including the administration of intravenous immunoglobulin and steroids. Patients with lymphoma exhibit various neuropathic patterns, but neurolymphomatosis is the major cause of neuropathy. Misdiagnoses of neurolymphomatosis as chronic inflammatory demyelinating polyneuropathy are frequent due to a presence of a demyelinating pattern and the initial response to immunomodulatory treatments. The possibility of the concomitance of lymphoma should be considered in various types of neuropathy, even if the diagnostic criteria of chronic inflammatory demyelinating polyneuropathy are met, particularly in patients complaining of pain.

Kinesin and cytoplasmic dynein in spinal spheroids with motor neuron disease

Kinesin and cytoplasmic dynein are two major molecular motors responsible for fast axonal transport. As visualized by immunohistochemistry with monoclonal antibodies, both motors were found to be distributed throughout the cell bodies, dendrites and axons of motor neurons in normal human spinal cords. Large axonal swellings, spheroids, in the spinal cords of patients with motor neuron disease showed massive accumulation of kinesin co-localized with highly phosphorylated neurofilaments. Of 114 spheroids in five spinal cords, 87% were stained heavily with the three anti-kinesin antibodies used in this study. Cytoplasmic dynein was scarce or absent in most of the spheroids. These findings suggest that kinesin selectively accumulates in the spheroids of motor neuron axons, causing disturbance of the machinery for anterograde fast axonal transport in motor neuron disease.

Expression of a 72-kDa heat shock protein, and its cytoprotective function, in gastric mucosa in cirrhotic rats

BackgroundPortal hypertensive gastropathy (PHG) is a clinical entity that is observed frequently in patients with liver cirrhosis. In PHG, gastric mucosa is highly susceptible to mucosal injury caused by noxious agents. Many studies, including ours, have reported that a 72-kDa heat shock protein (HSP72) has a crucial cytoprotective function in gastric mucosa. In this study, we investigated the expression and cytoprotective effect of HSP72 on gastric mucosa in portal hypertensive rats.MethodsPHG was produced by bile duct ligation (BDL) or carbon tetrachloride administration in male Sprague-Dawley rats. The expression of HSP72 in the gastric mucosa was evaluated by Western blotting. Induction of gastric mucosal HSP72 by 6-h water-immersion stress was compared between cirrhotic and control rats. Also, mucosal protective abilities against hydrochloric acid (HCl; 0.6 N) following pretreatment with water-immersion stress to induce HSP72 were studied in both groups.ResultsPortal venous pressure was significantly higher in cirrhotic rats compared with control rats (P < 0.05). Baseline expression (before water-immersion stress) of mucosal HSP72 was significantly lower in cirrhotic rats compared with control rats. HCl-induced gastric mucosal lesions were significantly suppressed in control rats compared with cirrhotic rats, especially when HSP72 was preinduced by water-immersion stress.ConclusionsThese findings suggest that HSP72 in the gastric mucosa plays a crucial role with respect to cytoprotection; the induction of HSP72 may provide therapeutic strategies for protection against mucosal injury in PHG.

Kinesin accumulation in chick spinal axonal swellings with β,β′-iminodipropionitrile (IDPN) intoxication

Abstract Kinesin is a major molecular motor responsible for anterograde axonal transport. Chicks were injected with β , β ′-iminodipropionitrile (IDPN) to induce axonal swellings in spinal motor neurons and spinal sensory ganglion neurons. Cylindrical swollen axons were found in the anterior horn and anterior funiculus of the spinal cord, anterior root, and spinal ganglia. All of the axonal swellings were heavily stained with two anti-kinesin monoclonal antibodies. The swellings were mildly stained with an anti-cytoplasmic dynein and anti-tubulin antibodies, and weakly stained with an anti-tau antibody. These suggest the isolated disturbance of kinesin transport with neurofilament accumulation in IDPN intoxication.

The expression of Fas and Fas ligand, and the effects of interferon in chronic liver diseases with hepatitis C virus

In viral hepatitis, binding of Fas ligand (FasL) with Fas expressed on the surfaces of infected hepatocytes induces apoptosis, removing hepatitis virus along with infected hepatocytes. We measured serum concentrations of soluble Fas (sFas) and FasL (sFasL), expression of membrane-bound FasL, and expression of FasL-mRNA in patients with chronic hepatitis C without cirrhosis (CH-C) and chronic hepatitis C with liver cirrhosis (LC-C). In CH-C, sFasL concentrations were lower and FasL-mRNA expression was significantly less than in volunteers. In LC-C, sFas concentrations were significantly greater than in healthy volunteers, while sFasL, membrane-bound FasL expression, and FasL-mRNA expression did not show significant differences. We also examined these variables over 24 h following the first interferon (IFN) treatment in patients with CH-C. Serum concentrations of sFas and sFasL, and FasL-mRNA expression increased markedly beyond amounts present before IFN injection until 12 h after IFN injection. However, membrane-bound FasL expression decreased until 6 h, followed by an increase until 24 h. Our findings suggest that the ratio of membrane-bound FasL to sFasL may be regulated to remove virally infected cells in CH-C. In addition, apoptosis mediated by the Fas/FasL system may be influenced by IFN injection for treatment of CH-C.

Purkinje Cell Loss in the Cerebellar Flocculus in Patients with Ataxia with Ocular Motor Apraxia Type 1/Early-Onset Ataxia with Ocular Motor Apraxia and Hypoalbuminemia

We genetically screened patients with ataxia with ocular motor apraxia type 1 (AOA1)/early-onset ataxia with ocular motor apraxia and hypoalbuminemia (EAOH), with a Japanese variant form of Friedreich’s ataxia. Three patients were found to have a homozygous insertion mutation of the aprataxin gene (689insT). An elder sister of a patient in this series died of cerebral hemorrhage at the age of 45, and underwent autopsy. In her cerebellar cortex, the mean density of Purkinje cells in the flocculus had predominantly decreased to 6.7% of normal controls, whereas the Purkinje cells in the other areas of the cerebellar hemisphere had decreased to 78.2%. This suggests that the cerebellar flocculus is the primary affected lesion in AOA1/EAOH, which should be associated with ocular motor apraxia.

Prevalence of dystonia in Akita prefecture in Northern Japan

We investigated the prevalence of dystonia in Akita Prefecture (population was 1,166,967 as of 1 November 2004). The prevalence of primary generalized and focal dystonia is estimated to be 0.68 and 14.4 per 100,000 persons, respectively. Blepharospasm is the most common primary dystonia in this area.

A novel sacsin mutation in a Japanese woman showing clinical uniformity of autosomal recessive spastic ataxia of Charlevoix-Saguenay

Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) was originally described among French Canadians in the Charlevoix-Saguenay-Lac-Saint-Jean region of Quebec (OMIM 270550).1 The gene responsible for ARSACS was identified as sacsin, and frameshift (8585 deletion T, 2805X) and nonsense (C7245T, R2355X) mutations were reported in Quebec.2 Recently, patients with other mutations have been described in countries elsewhere.3 These showed not only the spastic ataxia with peripheral neuropathy recognised in Quebec, but some additional features as well.3 Here we describe a female Japanese ARSACS patient with a novel nonsense mutation (C3774T, Q1198X), which resulted in a shorter truncated protein than those of the French Canadian patients. We report the details of her clinical and genetic data, and discuss the correlation between mutations and phenotypes in ARSACS. The patient was a 39 year old woman who first walked at 12 months. Her gait was normal in early childhood. A spastic gait started at nine years of age, but she made no complaint about it for many years. After the age of 35 she complained of unsteadiness in her gait and clumsiness in her hands. Her gait disturbance progressed and she visited our clinic at the age of 37. Consanguinity was not identified in her parents. Family members (parents and one brother) and other relatives have …

Pontine Atrophy in Spinocerebellar Ataxia Type 6

To investigate the clinical range of spinocerebellar ataxia type 6 (SCA6), we screened CAG repeat expansion in the voltage-dependent alpha 1A calcium channel gene (CACNL1A4) in 71 ataxic patients in 60 families; 54 patients in 43 families with hereditary ataxia and 17 sporadic patients. Thirteen patients with SCA6 were detected to have elongated CAG in CACNL1A4. Of these, 7 patients had been diagnosed as having hereditary cerebellar cortical atrophy, and 6 patients had been found to have sporadic occurrence. One patient showed distinct pontine atrophy with prominent horizontal or oblique gaze nystagmus which is an unusual feature in sporadic olivopontocerebellar atrophy. For the efficient screening of SCA6, we would propose testing CAG repeat expansion in CACNL1A4, in patients with one of two markers: (1) horizontal or oblique gaze nystagmus without other eye movement disorders, (2) pure cerebellar atrophy, even if occurrence is sporadic. We should note that the pontine atrophy could also be caused by CAG repeat expansion in CACNL1A4.