Biomedical subjects

Shiro Matsubara

Publications and source records attributed to Shiro Matsubara.

5 recordsLinked to original sources

PubMed2005

Klotho insufficiency causes decrease of ribosomal RNA gene transcription activity, cytoplasmic RNA and rough ER in the spinal anterior horn cells.

The klotho gene was identified in 1997 as the gene whose severe insufficiency (kl/kl) causes a syndrome resembling human aging, such as osteoporosis, arteriosclerosis, gonadal atrophy, emphysema, and short life span in a mouse strain. Regarding the gait disturbance reported in kl/kl mice, the present study examined the spinal cord of kl/kl mice, and revealed decreases in the number of large anterior horn cells (AHCs), the amount of cytoplasmic RNA, the number of ribosomes and rough endoplasmic reticulum (rER), and the activity of ribosomal (r) RNA gene transcription without significant loss of the total number of neurons in the ventral gray matter. Increased immunostaining of phosphorylated neurofilament in the AHCs and of glial fibrillary acidic protein in reactive astrocytes in the anterior horn of kl/kl mice were also observed. On the other hand, the posterior horn was quite well preserved. The results suggest that the kl/kl insufficiency causes atrophy and dysfunction of the spinal AHCs through decreased activity of rRNA gene transcription, which may reduce the amount of cytoplasmic RNA and the number of ribosomes and rER. These findings resemble those found in the spinal cord of patients with classic amyotrophic lateral sclerosis (ALS). The results show that klotho gene insufficiency causes dysfunction of the protein synthesizing system in the AHCs, and might indicate the klotho gene is involved in the pathological mechanism of classic ALS. The kl/kl is a new animal model of AHC degeneration, and may provide clues to understanding the etiology of classic ALS.

Animals↗

PubMed2004

[Inclusion body myositis after interferon-alpha treatment in a patient with HCV and HTLV-1 infection].

We report the first case of inclusion body myositis (IBM) which occurred after interferon-alpha treatment for chronic hepatitis C. A 63-year-old man contracted hepatitis C virus (HCV) and human T cell leukemia virus type 1 (HTLV-1) from a blood transfusion at age of 18. At age 57, he was treated with interferon-alpha (IFN alpha) for chronic hepatitis C. A month later, he developed muscle weakness in the proximal part of his lower extremities. IBM was diagnosed after a muscle biopsy at age 62. Steroid therapy improved his muscle power. One year later, worsening of his hepatic condition required re-administration of IFN alpha after gradual decrease and discontinuation of prednisolone. However, several days later, he rapidly became weaker and required a cane to walk. Elevated serum creatine kinase (2,199IU/L) and abnormal intensity in his MRI of thigh were demonstrated. The second muscle biopsy, performed after obtaining the informed consent from our patient, confirmed relapse of IBM. His symptoms improved again after discontinuation of IFN alpha and re-induction of prednisolone. Although a few cases each of IBM associated with HCV or HTLV-1 have been reported, the pathogenesis of virus-associated inflammatory myositis has not been clearly understood. Moreover, there has been no description on IBM associated with IFN alpha treatment, though several cases of polymyositis have been reported. Our case suggests that infection of HCV and HTLV-1 may be immunologically involved in the development of IBM and that IFN alpha can be directly related to onset and relapse of IBM.

HTLV-I Infections↗

PubMed2004

[A case of sensory ataxic neuropathy and polymyositis of perivascular type associated with Sjögren's syndrome].

A 53-year old woman was admitted with of sensory disturbance and weakness of lower limbs which had progressed slowly in the previous ten years. A diagnosis of sensory ataxic neuropathy associated with Sjögren's syndrome was made. A sural nerve biopsy showed marked loss of myelinated fibers. A muscle biopsy revealed atrophy of muscle fibers along with perivascular cellular infiltration. The dorsal root ganglia have been considered to be the main site affected in the ataxic neuropathy in Sjögren's syndrome. However, the evidence for that was meager. The perivascular inflammatory change observed in the muscle may also have existed in the peripheral nervous system including the dorsal root ganglia.

Ataxia↗

PubMed2003

An aggregate-prone conformational epitope in trinucleotide repeat diseases.

A broad range of neurodegenerative disorders is associated with accumulation of misfolded protein that is toxic to the cells. Knowledge of the conformational structure of the protein implicated is essential for understanding how an aggregate-prone protein causes disease. Here we show that a conformational epitope associated with aggregation property and cell toxicity is preserved in homopolymeric amino acid stretches implicated in oculopharyngeal muscular dystrophy (OPMD) and polyglutamine diseases. These disorders are characterized by the nuclear inclusions and a genetic gain of function. This is the first report of a candidate pathogenic structure, which may trigger aggregation of the proteins in trinucleotide repeat diseases including OPMD and polyglutamine diseases. It provides a possible therapeutic target useful for these disorders.

Animals↗

PubMed2003

[Appearance of numerous lobulated fibers after a protracted course of 18 years in a case of dermatomyositis].

A woman aged 47 first noticed weakness in her proximal muscles of all four limbs at the age of 29. After the initial investigation at our hospital, she was diagnosed as having dermatomyositis associated with primary biliary cirrhosis. In the following 18 years, she was kept on steroids. Although she responded to this treatment, weakness progressed slowly necessitating re-investigation including a second muscle biopsy. It was remarkable that in her first muscle biopsy, no lobulated fiber had been, while they were numerous in the second one. As a result of these studies, possibilities of limb-girdle muscle dystrophy (LGMD) and other myopathies remained but were ultimately ruled out after immunohistochemical/and genetic studies, and the original diagnosis was confirmed. Her weakness responded to an increased dose of steroids. Lobulated fibers were originally described in LGMD, and were reported also in the facioscapulohumeral muscular dytrophy and other hereditary myopathies. They have been rarely described in the inflammatory myopathies. Based on the observation of the present case, we concluded that lobulated fibers have little disease specificity and can newly appear in the course of any chronic myopathies including acquired myopathies like dermatomyositis.

Anti-Inflammatory Agents↗