Mitsuru Kawai

A nasal allergy model developed in the guinea pig by intranasal application of 2,4-toluene diisocyanate

An experimental model of nasal allergy has been developed in guinea pigs by intranasal application of 2,4-toluene diisocyanate (TDI). A 10% TDI solution in ethyl acetate was painted onto the nasal vestibuli of the animals once a day for 5-10 days. During the course of repeated application of TDI, the number of animals which secreted rhinorrhea containing eosinophils increased. Morphological survey of the nasal mucosa showed infiltration of eosinophils and some other changes indicative of acute inflammation. Moreover, mast cells were found not only in the subepithelial connective tissue but also in the epithelial layer. Nasal mucus obtained from the mucosa has been found to be an effective test material for studies of nasal allergy. A striking decrease of specific granules was found in some mast cells contained in the mucus. In parallel with the symptomatology, biochemical and serological studies suggested the involvement of type I allergy in the experimental system; TDI-specific histamine release from the nasal mucosa and positive passive cutaneous anaphylaxis were found 3 weeks after the application of TDI.

Biallelic Mutations in MYPN, Encoding Myopalladin, Are Associated with Childhood-Onset, Slowly Progressive Nemaline Myopathy

Nemaline myopathy (NM) is a common form of congenital nondystrophic skeletal muscle disease characterized by muscular weakness of proximal dominance, hypotonia, and respiratory insufficiency but typically not cardiac dysfunction. Wide variation in severity has been reported. Intranuclear rod myopathy is a subtype of NM in which rod-like bodies are seen in the nucleus, and it often manifests as a severe phenotype. Although ten mutant genes are currently known to be associated with NM, only ACTA1 is associated with intranuclear rod myopathy. In addition, the genetic cause remains unclear in approximately 25%-30% of individuals with NM. We performed whole-exome sequencing on individuals with histologically confirmed but genetically unsolved NM. Our study included individuals with milder, later-onset NM and identified biallelic loss-of-function mutations in myopalladin (MYPN) in four families. Encoded MYPN is a sarcomeric protein exclusively localized in striated muscle in humans. Individuals with identified MYPN mutations in all four of these families have relatively mild, childhood- to adult-onset NM with slowly progressive muscle weakness. Walking difficulties were recognized around their forties. Decreased respiratory function, cardiac involvement, and intranuclear rods in biopsied muscle were observed in two individuals. MYPN was localized at the Z-line in control skeletal muscles but was absent from affected individuals. Homozygous knockin mice with a nonsense mutation in Mypn showed Z-streaming and nemaline-like bodies adjacent to a disorganized Z-line on electron microscopy, recapitulating the disease. Our results suggest that MYPN screening should be considered in individuals with mild NM, especially when cardiac problems or intranuclear rods are present.

Allergic Granulomatous Angiitis (Churg-Strauss Syndrome) Associated with Allergic Bronchopulmonary Candidiasis

We describe a case of Churg-Strauss syndrome (CSS) associated with allergic bronchopulmonary candidiasis (ABPC). A 61-year-old man who had been given a diagnosis of ABPC based on serologic and radiographic findings experienced pain and purpuric rash on the left leg accompanied with motor weakness. The diagnosis of CSS was made from skin, nerve and muscle biopsies. Although immunosuppressant and prednisolone were administered and resulted in transient improvement, candidal pneumonia was suspected to have developed 60 days after the administration and the patient finally died of respiratory failure. To our knowledge, this is the first case of CSS associated with ABPC.

Separation and determination of theophylline from paraxanthine in human serum by reversed-phase high-performance liquid chromatography

A sensitive and highly specific method for the determination of theophylline in serum by high-performance liquid chromatography (HPLC) has been developed. Theophylline was completely separated from paraxanthine, a major metabolite of caffeine which has been known to interfere with most isocratic reversed-phase HPLC methods, with a mixture of acetonitrile/tetrahydrofuran/acetate buffer (10 mM, pH 5.0; 5:1:94, v/v %) as the mobile phase using a C18 bonded reversed-phase column. Neither the other xanthine and uric acid derivatives nor numerous drugs tested were found to interfere. The proposed method was applied to therapeutic monitoring utilizing its excellent precision, reproducibility and high specificity for theophylline.

Brain volume analyses and somatosensory evoked potentials in multiple system atrophy

We investigated a progression of brain atrophy and somatosensory system dysfunction in multiple system atrophy (MSA). Subjects were 21 MSA patients [12 MSA-C (cerebellar type) and 9 MSA-P (parkinsonism type)]. The relative volumes of cerebrum, brainstem and cerebellum to the intracranial volume were obtained from three-dimensional computed tomography (3D-CT) of the brain. The median nerve somatosensory evoked potentials (SEPs) were recorded, and the latencies and amplitudes of N9, N11, P13/14, N20 and P25 components were measured. We studied correlations between brain volumes, SEP and clinical features. The brainstem and cerebellar atrophies were aggravated with progression of the disease. The central sensory conduction time (CSCT) was progressively prolonged in parallel with the disease duration irrespective of the actual age of the patients. In MSA patients, the volume reductions of cerebellum and brainstem could be one of structural markers of disease progression, and the sensory pathway is progressively involved with the progression of disease processes.

Selective muscle involvement in a family affected by a second LIM domain mutation of fhl1: An imaging study using computed tomography

Mutations in the four-and-a-half LIM domains 1 gene (fhl1) are associated with various phenotypes of hereditary myopathies, including reducing body myopathy. We describe here a mother, daughter and son suffering from FHL1 myopathy with a mutation in the second LIM domain of fhl1. We investigated whether there is a characteristic muscle involvement in both sexes. Despite the variety of symptoms exhibited by the male and female patients, the systemic imaging studies showed a similar pattern: the flexor muscles of the brachium and thigh were affected earlier than the extensor muscle with a profound degeneration of the paraspinal muscles. These findings may include one of the characteristic clinical features for suspecting a mutation in the second LIM domain.

Specific binding of Ulex europaeus agglutinin I lectin to sarcolemma of distal myopathy with rimmed vacuole formation

Ulex europaeus agglutinin I (UEA I) binding was studied in 83 patients with various neuromuscular disorders. UEA I labelled endomysial capillaries and endothelial cells of perimysial blood vessels in all the examined muscles. There was no UEA I binding to muscle fibres except for all (9) cases of distal myopathy with rimmed vacuole formation (DMRV), 1 of 5 cases of inclusion body myositis and 1 of 36 cases of inflammatory myopathies. The UEA I binding was completely eliminated by preincubation of UEA I solution with l-fucose. Using electron microscopy, the UEA I binding was localized to sarcolemma and intrasarcoplasmic membranous organelles other than mitochondria. Myosatellite cells were not labelled. These findings revealed the existence of fucosylated proteins or lipids in a subset of skeletal muscles suffering from DMRV. Biochemical identification of the fucosylated substance and further detailed study on subcellular localization of UEA I binding may yield important clues to the unknown pathogenesis of DMRV.