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F Usuki

Publications and source records attributed to F Usuki.

30 records · Page 2Linked to original sources
PubMed1991

Cardiomyopathy, mental retardation, and autophagic vacuolar myopathy. Abnormal MRI findings in the head.

A 21-year-old man with childhood-onset mental retardation, non-obstructive hypertrophic cardiomyopathy, and vacuolar myopathy is presented. A histopathological study of biopsied skeletal muscle showed lysosomal glycogen storage mimicking acid maltase deficiency, but biochemical analysis showed normal acid alpha-glucosidase activity. Glycogenosomes were also recognized in endothelial cells on electronmicroscopic examination of biopsied skeletal muscle. Magnetic resonance imaging (MRI) findings in the head revealed the involvement of the central nervous system. This is a new type of lysosomal glycogen storage disease with multisystemic involvement. The specific biochemical defect in this disorder remains to be elucidated.

Adult↗
PubMed1991

Vacuolar myositis with expression of both MHC class I and class II antigens on skeletal muscle fibers.

We describe here a 10-year-old patient with high levels of serum IgE and inflammatory myopathy whose muscle fibers exhibit excessive autophagy. Previous studies have demonstrated surface expression of class I MHC antigens on muscle fibers from patients with inflammatory myopathy. The muscle fibers of this patients showed marked expression of both class I and class II MHC antigens. The reaction products were demonstrated not only on sarcolemma but also in and around some vacuoles. Both CD4-positive and CD8-positive T-lymphocytes were noted in inflammatory exudates surrounding these fibers but B-lymphocytes were rare. We hypothesize that myocyte expression of both class I and class II antigens may play a role in the pathogenesis of this new type of inflammatory myopathy.

Autoimmune Diseases↗
PubMed1991

[Juvenile parkinsonism in monozygotic twins].

A pair of monozygotic twins concordant for juvenile Parkinsonism are described. These twin sisters have lived together until 18 years old. Twin A noted tremor in the right hand and right-sided stiffness and slowness at the age 20. Initially, a marked improvement was shown with L-dopa treatment. However, one year after the beginning of treatment, dopa-induced dyskinesia appeared. Twin B noted tremor and right-sided stiffness and basal ganglia calcification in both patients. These twin patients suggest that genetic factors may play an important role in the cause of juvenile Parkinsonism.

Adult↗
PubMed1989

Hyperestrogenemia in neuromuscular diseases.

In order to elucidate the relationship between certain neuromuscular diseases and gonadal hormones, we measured the levels of serum estrogens and other sex-related hormones. The values were compared with those for age-matched controls. The cases, comprising bulbospinal muscular disease of the Kennedy-Alter-Sung type, Kugelberg-Welander disease, amyotrophic lateral sclerosis, and Duchenne muscular dystrophy, were all euthyroid males. The baseline levels of serum estrone were significantly higher in all of the patients than in age-matched normal subjects. Serum baseline testosterone, LH and FSH levels were all essentially normal, except low FSH levels in Duchenne muscular dystrophy. Since our patients had no overweight, liver or glandular abnormalities, we presume that the elevated serum estrone levels have resulted from increased peripheral androgen-to-estrogen conversion.

Adolescent↗
PubMed1989

Nasu-Hakola disease (membranous lipodystrophy). Clinical, histopathological and biochemical studies of three cases.

We report 3 cases of Nasu-Hakola disease found in 2 families. These cases had identical clinical features with progressive spastic paraplegia and severe dementia after adolescence. They had no history of any skeletal symptoms, but roentgenographs of their bones presented characteristic evidence of polycystic osteodysplasia. All cases revealed not only manifestations of this condition in the central nervous system, but also peripheral neuropathy with axonal degeneration. The membranous structures in the adipose tissues appeared histochemically to be composed of a kind of compound glycolipid or glycoprotein. Histopathologically, the biopsied rectum showed the infiltration of many histiocytes in the mucosa and ultrastructurally, the granules in these histiocytes showed many membrane-bound vacuoles of different sizes. Interestingly, the histochemical reactivity of the material in the granules was very similar to that of membranous structures in adipose tissues. In the biochemical analysis of lipids in affected adipose tissues, no marked abnormalities were found in the patients. Nasu-Hakola disease is not a typical form of lysosomal storage disease, because lysosomal enzyme activities remain normal and there is no accumulation of urinary oligosaccharides and lipids, no vacuolation of lymphocytes, and no hepatosplenomegaly. However, histochemical findings suggest that the lysosomes may be secondarily involved in this disease, and that the formation of membranous structures might be related to the disturbance of glycolipid or glycoprotein metabolisms.

Adipose Tissue↗
PubMed1988

alpha-Glucosidase isoenzymes in normal and acid maltase-deficient human skeletal muscles.

One acid alpha-glucosidase and two neutral alpha-glucosidases were separated from human skeletal muscle by DEAE-cellulose column chromatography. The appearance of the two human neutral alpha-glucosidase isoenzymes was found to be age dependent. We called them "fetal" and "adult" neutral alpha-glucosidases. The biochemical properties of the fetal and adult types of neutral alpha-glucosidases appeared to be similar to those previously reported for neutral alpha-glucosidases AB and C, respectively. The neutral alpha-glucosidase activity in the column eluate of the infantile acid maltase deficiency (AMD; 5-month-old) muscle was completely of the adult type, whereas 18% of the total neutral alpha-glucosidase activity in age-matched control muscle was of the fetal type. In contrast, the eluate of the late-onset AMD (32-year-old) muscle contained both the adult and fetal neutral alpha-glucosidases, 68 and 32%, respectively.

Adult↗
PubMed1988

Reappearance of embryonic neutral alpha-glucosidase isoenzyme in acid maltase-deficient muscle of Japanese quail.

Two neutral alpha-glucosidase isoenzymes were isolated from the muscle of Japanese quails with late-onset acid maltase deficiency. One isoenzyme is predominantly expressed in embryonic muscle and the other in adult muscle. The time of switching from one to the other of these two neutral alpha-glucosidases was the same as in normal birds. The glycogen content in acid maltase-deficient muscle was not inversely proportional to the amount of embryonic neutral alpha-glucosidase. From the results, we conclude that (i) the transition of neutral alpha-glucosidase from the embryonic to the adult type is not influenced by the disease, and (ii) the embryonic neutral alpha-glucosidase seems not to be directly correlated with glycogen storage in skeletal muscle. In acid maltase-deficient muscle, the activity of the embryonic type began to increase again from 14 days after hatching, and attained a level corresponding to 18% of the total neutral alpha-glucosidase activity at 3 months (P less than 0.025). Its biochemical characteristics were the same as those of the normal embryonic neutral alpha-glucosidase. It should be clarified why the reappearance of the normal embryonic type occurs in acid maltase-deficient adult muscle and whether or not the reappearance of the embryonic neutral alpha-glucosidase represents regenerating muscle.

Animals↗
PubMed1987

Acid maltase deficiency in the Japanese quail; early morphological event in skeletal muscle.

The skeletal muscle of Japanese quails with acid maltase deficiency (AMD) was studied morphologically at various developmental stages, from the 16th embryonal day up to 3 months after hatching. Membrane-bound glycogen particles began to appear in the affected skeletal muscle at the 16th embryonal day. In normal embryonic muscles, a certain amount of free glycogen particles was observed but they were not membrane-bound. Therefore, this is the earliest morphological event in the muscle of Japanese quails with AMD. In muscle at 3 weeks after hatching, the initial focal degeneration of myofibrils was recognizable but it was not associated with autophagic vacuoles. Quails with AMD developed muscle weakness and difficulty in lifting their wings at about 3 months after hatching: then numerous autophagic vacuoles were present. The formation of large autophagic vacuoles followed by fiber loss and fatty replacement seemed to contribute to the progressive muscle weakness. The study of Japanese quail with AMD will greatly facilitate the elucidation of the pathogenetic mechanism and is also a useful model for therapeutic trials in human AMD.

Animals↗
PubMed1986

Isolation and characterization of three alpha-glucosidases from the Japanese quail.

We have defined one type of acid alpha-glucosidase and two types of neutral alpha-glucosidases from quail skeletal muscle on the basis of differences in the elution patterns on a DEAE-cellulose column. The appearance of the two neutral alpha-glucosidase isoenzymes was age-dependent. A decrease in acid alpha-glucosidase activity was demonstrated in Japanese quails with glycogenosis type II. The characteristics of these three alpha-glucosidase isoenzymes are described.

Age Factors↗
PubMedDate not supplied

Developmental study of alpha-glucosidases in Japanese quails with acid maltase deficiency.

In Japanese quails with late-onset acid maltase deficiency (AMD), the activity of acid alpha-glucosidase was severely reduced to approximately 16% of the normal level from an embryonic age. The kinetic characteristics and inhibition by Zn indicated that the residual activity was responsible for the intrinsic activity of acid alpha-glucosidase. However, in affected embryos, the glycogen content and other lysosomal enzyme activities were normal, despite the low acid alpha-glucosidase activity. In a separate study, we found the existence of two age-dependent neutral alpha-glucosidases--"embryonic" and "adult" alpha-glucosidases. In affected quails, the transition from the embryonic neutral alpha-glucosidase to the adult type was not influenced by the disease. The activity toward maltose and glycogen of the embryonic neutral alpha-glucosidase may explain the normal glycogen content in the affected embryos.

Animals↗
PubMedDate not supplied

Phenotypic Duchenne muscular dystrophy with C-terminal domain.

We report a patient with X-linked muscular dystrophy who had rapidly progressive muscle weakness and became wheelchair-bound at age 10 years. Clinically, he was diagnosed as having Duchenne muscular dystrophy; however, he was diagnosed as having Becker muscular dystrophy by dystrophin tests using a C-terminal monoclonal antibody. No immunolabelling was observed with a monoclonal antibody against the N-terminal domain. Multiplex polymerase chain reaction analysis revealed the deletion of exons 3-19. The data suggest that the deletion of the N-terminal domain of dystrophin can cause a severe phenotype even when the C-terminus of the protein is well preserved.

Adolescent↗