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Biomedical subjects

M Takamori

Publications and source records attributed to M Takamori.

At least 19 recordsLinked to original sources
PubMed2005

Long-term treatment of generalised myasthenia gravis with FK506 (tacrolimus).

Efficacy and safety of long term use of FK506 (2-4.5 mg/day) for a maximum of two years were evaluated in 12 patients with generalised myasthenia gravis (MG). At the end of the study, eight patients (67%) showed improvement in either MG score or Activities in Daily Living score, and prednisolone dosage could be reduced in seven patients (58%), with a mean reduction ratio of 37%. Long term use of FK506 for MG can be more effective than short term administration, with no serious side effects.

Activities of Daily Living↗
PubMed2005

Patterns and severity of neuromuscular transmission failure in seronegative myasthenia gravis.

OBJECTIVES: To compare the clinical and electrophysiological features of myasthenia gravis (MG) patients with (seropositive) or without (seronegative) antibodies to acetylcholine receptor. To investigate whether antibodies to muscle specific kinase (MuSK) and ryanodine receptor (RyR) are associated with particular features. METHODS: Clinical profiles and single fibre electromyography (SFEMG) in the extensor digitorum communis (EDC) were reviewed in consecutive 57 seropositive and 13 seronegative patients. Antibodies to MuSK and RyR were measured by immunoassays. RESULTS: Of the 13 seronegative patients, four (31%) were positive for MuSK antibodies and seven (54%) were positive for RyR antibodies, including all four MuSK positive patients. Clinical features were similar at presentation for seropositive and seronegative patients, but MuSK positive patients frequently developed myasthenic crises. Despite the similar clinical severities at the time of examination, the proportion with positive jitter (93% of seropositive patients, 50% of MuSK positive patients, and 44% of MuSK negative patients) and the extent of jitter (mean consecutive difference: 76 micros in seropositive patients, 36 micros in MuSK positive patients, and 30 micros in MuSK negative patients) were less in seronegative MG patients compared with seropositive MG patients. CONCLUSIONS: Seronegative MG is heterogeneous with respect to the presence of antibodies to MuSK. Impairment of neuromuscular synaptic transmission in EDC is less marked in seronegative than seropositive MG despite the similar clinical severity. This discrepancy may partly reflect the distribution of affected muscles in seronegative patients, but it is possible that other factors, such as impaired excitation-contraction coupling resulting from RyR antibodies, contribute to the clinical phenotype.

Adult↗
PubMed2004

Anti-ryanodine receptor antibodies and FK506 in myasthenia gravis.

Anti-ryanodine receptor (RyR) antibodies were measured in sera from 33 myasthenia gravis (MG) patients using three peptides from the human RyR1 sequence, two C-terminal peptides included in the functional calcium release channel, and an N-terminal peptide implicated in ion-conduction. Antibodies were more frequently positive against the two C-terminal peptides, particularly in thymoma-associated MG. In a preliminary open trial with FK506, immunosuppressant and enhancer of RyR-related sarcoplasmic calcium release, the authors observed the sustained benefits in anti-RyR-positive MG patients.

Adult↗
PubMed2001

An investigation of cell proliferation and soluble mediators induced by interleukin 1beta in human synovial fibroblasts: comparative response in osteoarthritis and rheumatoid arthritis.

OBJECTIVES AND DESIGN: The difference in cell proliferation and release of soluble factors in response to interleukin 1beta (IL-1beta) in fibroblasts obtained from patients with osteoarthritis (OA) and rheumatoid arthritis (RA) and from normal skin has been investigated. TREATMENT: The cells were treated with recombinant IL-1beta in the presence or absence of pharmacological agents for 24 h or 48 h. METHODS: Cell proliferation was examined by WST-1 assay, and the amounts of interleukin-6 (IL-6), interleukin-8 (IL-8), macrophage colony stimulating factor (M-CSF), vascular endothelial growth factor (VEGF), matrix metalloproteinase-1 (MMP-1), and prostaglandin E2 (PGE2) were measured by enzyme linked immunosorbent assay (ELISA). RESULTS: IL-1beta dose-dependently enhanced the proliferation of all fibroblasts. The proliferative response to IL-1beta in RA synovial fibroblasts was greater than that in OA synovial and skin fibroblasts. However, there was no difference in spontaneous levels of soluble factors between OA and RA fibroblasts, though medium concentrations of IL-1beta-released VEGF, MMP-1, and PGE2, but not cytokines, in RA were slightly higher than those in OA. Ability to release soluble mediators was pronouncedly increased at 3 h to 9 h after stimulating fibroblasts with IL-1beta for 1 h. The proliferative response to IL-1beta in all fibroblasts was inhibited by dexamethasone and the NF-kappaB inhibitor hymenialdisine but not the cyclooxygenase 2 (COX-2) inhibitor NS-398. But PGE2 prevented proliferation of RA fibroblasts when added to medium up to 3 h after IL-1beta stimulation. Dexamethasone also inhibited the release of IL-6, IL-8, and PGE2 induced by IL-1beta in both OA and RA fibroblasts. NS-398 exhibited an inhibition of IL-1beta-induced IL-6 production as well as PGE2 production. Hymenialdisine inhibited IL-6 production and reduced IL-8 production dependent on synovial cell strains. Methotrexate had no effect on the response to IL-1beta in synovial fibroblasts. CONCLUSION: The present results indicate that the activation of NF-kappaB plays an important role in the proliferative response to IL-1beta in human fibroblasts, and suggest that PGE2 acts as a modulator of cell proliferation in inflamed synovial tissue. It appears that the ability to produce soluble factors in RA synovial fibroblasts is not intrinsic. However, the response to IL-1beta in RA cells seems to be greater than that in OA cells.

Arthritis, Rheumatoid↗
PubMed2001

Homozygosity and linkage disequilibrium mapping of autosomal recessive distal myopathy (Nonaka distal myopathy).

Autosomal recessive distal myopathy or Nonaka distal myopathy (NM) is characterized by its unique distribution of muscular weakness and wasting. The patients present with spared quadriceps muscles even in a late stage of the disease. The hamstring and tibialis anterior muscles are affected severely in early adulthood. We have localized the NM gene to the region between markers D9S319 and D9S276 on chromosome 9 by linkage analysis. To further refine the localization of the NM gene, we conducted homozygosity and linkage disequilibrium analysis for 14 patients from 11 NM families using 18 polymorphic markers. All of the patients from consanguineous NM families were found to be homozygous for six markers located within the region between markers D9S2178 and D9S1859. We also provided evidence for significant allelic associations between the NM region and five marker loci. Examination of the haplotype analysis identified a predominant ancestral haplotype comprising the associated alleles 199-160-154-109 (marker order: D9S2179-D9S2180-D9S2181-D9S1804), present in 60% of NM chromosomes and in 0% of parent chromosomes. On the basis of the data obtained in this study, the majority of NM chromosomes were derived from a single ancestral founder, and the NM gene is probably located within the 1.5-Mb region between markers D9S2178 and D9S1791.

Adult↗
PubMed2001

Immunoadsorption in myasthenia gravis based on specific ligands mimicking the immunogenic sites of the acetylcholine receptor.

A specific system for antibody removal from blood circulation in myasthenia gravis (MG) patients was devised by use of the immunoadsorbent bound to an acetylcholine receptor (AChR) peptide that was synthesized corresponding to the sequence of residues 183-200 of the AChR alpha-subunit (alpha 183-200), antibodies which prevent the binding of ACh to AChR. The alpha 183-200 peptide was confirmed to be immunogenic for induction of an animal model of the disease and for reactivity with MG autoantibodies. We then made use of these results for immunoadsorption therapy through the antigen-antibody reaction on the molecular level, having given patients relief from myasthenic weakness. The greatest care was taken for the selection of an antigenic region in the molecular structure among various myasthenogenic domains of AChR and for the antigenic conformation of synthetic peptide as the adsorbent to react with antibodies raised against the native protein.

Animals↗
PubMed2001

Benign segmental myoclonus: electrophysiological evidence of transient dysfunction in the brainstem.

We present a 66-year-old patient with segmental myoclonus evoked by a brainstem infarction. The myoclonus appeared soon after a cerebrovascular accident and it was evident in the soft palate, jaw, neck, shoulders and upper limbs. Brain MRI showed infarction in the left pons and left cerebellum. Small amounts of orally administered clonazepam were remarkably effective. Electroencephalogram (EEG) and auditory brainstem response (ABR) were normal. Somatosensory evoked potential (SSEP) revealed delays in P 14 and N19 recorded at C3 by right median nerve stimulation. These findings were normalized in 4 days. Seg-mental myoclonus is thought to be evoked by olivary hypertrophy following cerebrovascular accident in the brainstem and is said to be resistant to medication. The limited involvement of the brainstem in our patient may account for the transient segmental myoclonus. The prognosis for this type of segmental myoclonus is excellent.

Aged↗
PubMed2000

Recombinant calcium channel is recognized by Lambert-Eaton myasthenic syndrome antibodies.

The authors studied sera from 36 patients with Lambert-Eaton myasthenic syndrome (LEMS) by immunoblots using the recombinant protein derived from the DNA sequence encoding for the domain III S5-S6 linker of the P/Q-type voltage-gated calcium channel al subunit. The results of 18 patients were positive for antibodies to this recombinant protein. The results of 2 of 10 patients with lung cancer without LEMS were also positive.

Antibodies↗
PubMed2000

Lambert-Eaton myasthenic syndrome as an autoimmune calcium-channelopathy.

Lambert-Eaton myasthenic syndrome (LEMS), often associated with small cell lung carcinoma (SCLC), is a disease of neuromuscular transmission in which antibodies directed against voltage-gated calcium channel (VGCC) in the motor nerve terminal play a crucial role in causing a deficient quantal release of acetylcholine. We focused attention on the P/Q-type VGCC, against which a majority of LEMS patients carry the specific antibody. Since the P/Q-type VGCC expresses in SCLC, the motor nerve terminal and SCLC may share a common VGCC antigen. In search for antigenic sites at the molecular level, We employed peptides or recombinant protein corresponding to the S5-S6 linker of each of four domains forming the alpha 1A subunit and tested their antigenicity. As the result, we specified the domain II, III and IV as immunodominant sites by the induction of an immune-mediated animal model of LEMS and the assay for antibodies in LEMS patients. Also, by use of peptides or recombinant protein corresponding to the synaptotagmin I, we found that in this VGCC-associated protein, the segment which exposes extracellularly during exocytosis can be antigenic for LEMS.

Animals↗
PubMed2000

Antibodies to calcium channel and synaptotagmin in Lambert-Eaton myasthenic syndrome.

In the Lambert-Eaton myasthenic syndrome (LEMS), an autoimmune disease that is often associated with lung cancer and characterized by reduced quantal release of acetylcholine from the motor nerve terminal, our studies to search for the target of LEMS antibodies have brought the voltage-gated calcium channel (VGCC) into relief. Among multiple types of VGCCs, the P/Q-type was highly recognized by LEMS antibodies. Using synthetic peptides or recombinant proteins as antigens, the study specified the S5-S6 linker regions in 3 of 4 domains as immunodominant sites in the molecular structure of P/Q-type VGCC alpha1 subunit. Synaptotagmin, one of the functionally VGCC-associated synaptic proteins, was also found to be an immunogen in the pathogenesis of LEMS.

Autoantibodies↗
PubMed2000

[A rapidly fatal case of severe falciparum malaria complicated with high-level metabolic acidosis].

A 67-year-old male was admitted with consciousness disturbance (JCS, III-200) after completing a 12-day tour to east Africa without malaria chemoprophylaxis. When he visited the hospital one day prior to the admission complaining of fever and a slightly sore throat, he did not mention the travel history. Soon after his travel history was revealed, blood films were prepared which showed abundant ring forms accompanied with a small number of trophozoites and schizonts of Plasmodium falciparum, with the parasitemia of 26%. Despite intravenous quinine infusion, first that of loading dose, his consciousness state (JCS, III-300), renal and hepatic functions and anemia (Hb, 5.8 g/dL) deteriorated progressively. Moreover, metabolic acidosis worsened with pH of 6.954, HCO3- of 3.4 mEq/L, BE of--27.0 mEq/L, PCO2 15.5 mmHg by arterial blood gas analysis, although he received a large volume of sodium bicarbonate solution. The patient died on the 4th day of his illness. According to the literature, it is suggested that the treatment of metabolic acidosis in severe faciparum malaria with sodium bicarbonate is sometimes harmful, since it can result in sodium overloading, which may then precipitate pulmonary edema/ARDS. However, alternative treatment regimens have not yet been established. Future investigation on the etiology and the proper treatment of metabolic acidosis associated with severe falciparum malaria is highly needed.

Acidosis↗
PubMed2000

[A case of glioblastoma multiforme which indicated the early stage on brain MRI].

A 57-year-old male was urgently carried to our hospital because of sudden loss of consciousness, lasting about 10 minutes. He had resumed consciousness before he arrived at our hospital. Neurologically, he had mild muscle weakness of the right arm. Deep tendon reflexes in the right upper extremity were reduced. In high level functions, speech disturbance, dysgraphia (disturbed ability to write Hiragana), and constructive apraxia were noted. A brain MRI upon admission showed a poorly demarcated, high signal intensity area in the cortical and subcortical layers of the left temporal and parietal lobes. This was visible on T 2 weighted images(T 2 WI), although no abnormalities were visible on T 1 weighted images(T 1 WI). No contrast enhancement was effected by Gd-DTPA. The patient was therefore suspected of having a tumor or degenerative disease and was monitored closely. About 4 months later after onset, his symptoms became aggravated, and brain MRI disclosed a marked low signal intensity area on T 1 WI and a heterogeneous high signal intensity area on T 2 WI. The abnormal signal intensity area was surrounded by extensive edema and mass effect. Ring-shaped, irregular, contrast enhanced areas were also visible. Cerebral angiography revealed a poorly demarcated tumor stain in the area supplied by the middle cerebral artery. The tumor was removed surgically and was histopathologically rated as glioblastoma multiforme(GBM). Because this case represents a valuable example of early stage of GBM, it will be discussed in this paper, along with differential diagnoses.

Brain Neoplasms↗
PubMed2000

[Receptor diseases in the field of neurology].

Based on the gene-related function and molecular structure of various receptors, neurological receptor diseases were reviewed from both the immunologic and genetic perspectives. The nicotinic acetyl-choline receptor (AChR), ryanodine receptor (RyR), omega-conotoxin receptor (P/Q-type voltage-gated calcium channel), dihydropyridine receptor (L-type voltage gated calcium channel), and androgen receptor have been found to be affected by autoantibodies and/or genetic anomalies. They reflect on various neurological diseases such as myasthenia gravis, congenital myasthenic syndrome, malignant hyperthermia and central core disease, paraneoplastic myasthenic syndrome, hereditary migraine and ataxias, hypokalemic periodic paralysis, and bulbospinal muscular atrophy. The interaction of calcitonin gene-related peptide with its receptor tends to compensate the dysfunction caused by antibodies to AChR and RyR. One should look for cancers or genetic disorders in the case of the receptor disease implicated in calcium channel function. Recent advances in search for the etiology of these diseases from the standpoints of immunology and genetics have opened an avenue in understanding the functional structure of receptors and the molecular sites responsible for receptor diseases.

Amino Acid Sequence↗
PubMed2000

[Autosomal dominant adult-onset spinal muscular atrophy with vocal cord paralysis: a case report].

This report concerns a 41-year-old female case of spinal muscular atrophy (SMA) associated with vocal cord paralysis. Her parents were not consanguineous. Her maternal grandmother and younger brother were suspected of having SMA. At age 37, she first experienced gait disturbance and began to have slowly progressive dysarthria and weakness of the extremities. Neurological examination revealed that she had inspiratory stridor, dysarthria and proximal muscular weakness of the extremities. Achilles tendon reflexes were absent, while there were no pathological reflexes or sensory disturbances. She showed a waddling gait and Gowers' sign. The laboratory data indicated mild elevation of serum CK. The nerve conduction study was normal, while the electromyographic study and muscle biopsy revealed neurogenic changes. We diagnosed the case as adult onset SMA of the autosomal dominant type. Laryngoscopy revealed that the patient had vocal cord paralysis, which was predominant in abductor muscles and of the posterior paralysis type according to the categories established by Isozaki. Genetic analysis showed no mutations in the genes of the neuronal apoptosis inhibitory protein and of the survival motor neuron.

Adult↗
PubMed1999

Calcium channel peptide can cause an autoimmune-mediated model of Lambert-Eaton myasthenic syndrome in rats.

The Lambert-Eaton myasthenic syndrome (LEMS) is a disorder of neuromuscular transmission characterized by the reduced quantal release of acetylcholine from the motor nerve terminal, wherein the P/Q-type of voltage-gated calcium channel (VGCC) and is attacked by a majority of LEMS antibodies. Using the molecular structure of the alpha1 subunit (consisting of 4 domains) of the P/Q-type VGCC as a reference, we synthesized the extracellular region (S5-S6 linker) of the domain III, known as the segment which plays an important role in channel functions. Six of the ten Lewis rats immunized with this synthetic peptide conjugated with carrier protein showed moderate weakness (grade 1 in a 3-graded scale, for myasthenic weakness in experimental animals) and a reduction in acetylcholine quantum content of end-plate potentials. Antipeptide antibodies raised in test rats reacted with omega-conotoxin MVIIC-sensitive cerebellar extract (P/Q-type VGCC) and the domain III peptide inhibited the binding of rat antibodies to VGCCs. Our findings suggest the identification of one of the potential epitopes of LEMS antibodies.

Animals↗