Shiro Mawatari

Adenyl cyclase abnormality in Duchenne muscular dystrophy: muscle cells in culture.

Cultured muscle cells from patients with Duchenne muscular dystrophy differed from cells of normal individuals and of patients with other muscle diseases. In Duchenne cells, basal activity of adenyl cyclase of myotubes was higher and was not stimulated significantly by epinephrine or isoproterenol, as it was in fused control cells, and the response to fluoride was less. The genetic defect in this disease may be an abnormality of the surface membrane of muscle.

Effect of propranolol on ATP in human erythrocytes—Comparison with ouabain

Abstract Propranolol enhanced utilization and generation of ATP in erythrocytes while ouabain suppressed both of them. After incubation of erythrocytes with propranolol, no change was noted in membrane ATPase activity while incubation with ouabain caused suppression of membrane ATPase. The effect of ouabain on erythrocyte ATP and lactate content is compatible with its inhibiting action of membrane ATPase activity. Propranolol may activate ATP-utilizing system(s) in the cytosol, or it may activate membrane ATPase activity only when combined with factor(s) lost during the preparation of the membrane. The above effect of propranolol may be unrelated to the β-adrenergic receptor blocking action since isoproterenol did not affect the erythrocyte ATP or lactate content and it did not counteract propranolol.

Erythrocyte membrane cation-stimulated ATPase activities in myotonic muscular dystrophy

The cation-stimulated ATPase activities of erythrocyte membranes from patients with myotonic muscular dystrophy (MyD) were compared with the activities in age- and sex-matched controls. The enzymes included ouabain-sensitive ATPase, Mg2+-ATPase and Ca2+ + Mg2+-ATPase. Sampling and processing of the materials from patients with MyD and controls were simultaneously done in each experiment. The enzyme activities were varied with or without EGTA in the reaction medium, or with different temperatures for membrane storage, but no significant differences between MyD and control were observed in any conditions. The present study indicates no specific abnormality of the cation-stimulated ATPase activities of erythrocyte membranes in MyD.

Emery-Dreifuss muscular dystrophy ☆: An autopsy case

We reported the autopsy findings in a 50-year-old man with typical clinical features of Emery-Dreifuss muscular dystrophy. Special attention was directed to the spinal cord and ventral spinal roots to determine whether cause of the muscle wasting was denervation or myopathy. Neuropathological studies disclosed no abnormality of the spinal cord, and the ventral spinal roots were intact. The skeletal muscles showed dystrophic changes of varying degrees, and marked cardiomyopathy was evident. We consider that muscle wasting in this man was due to muscular dystrophy.

Erythrocyte ATP in Duchenne dystrophy Effects of ouabain and propranolol

The ATP and lactate contents of erythrocytes from patients with Duchenne muscular dystrophy (DMD) were measured before and after incubation with or without glucose plus either ouabain or propranolol. Samples from patients and controls were obtained at almost the same time on the same day and processed simultaneously. The erythrocyte ATP content differed in adults and children, but there was no difference between DMD patients and age-matched controls. Ouabain suppressed, and propranolol enhanced, the changes of ATP and lactate, to the same extent in patients and in controls. We found no gross abnormalities in generation and utilization of ATP in erythrocytes in DMD, and the response to ouabain or propranolol appeared normal.

Na+ + K+ ATPase of erythrocyte membranes in Duchenne muscular dystrophy

We studied the Na+ + K+ ATPase activity of erythrocyte membranes from patients with Duchenne muscular dystrophy (DMD). Samples from patients and controls were obtained at almost the same time on the same day and processed simultaneously. Difference of anticoagulants, extent of washing the red cells, mechanical or osmotic disruption of the cells, presence or absence of EDTA in the washing solution of the ghosts, intentional removal of the peripheral proteins of the membranes, addition of DMD plasma to the assay system, and different temperatures of membrane storage caused no significant differences between DMD and control in Na+ + K+ ATPase or in response of the enzyme to ouabain.

Familial hypo-β-lipoproteinaemia

Abstract A family with partial deficiency of serum β-lipoprotein and serum cholesterol is reported, in which 7 of the 8 members examined presented with a similar biochemical abnormality. The pedigree indicated an autosomal dominant inheritance for this abnormality. None of the family members presented acanthocytosis. The profile of the concentrations of serum lipids in this family was somewhat different from those of the reported families with hypo-β-lipoproteinaemia. Only one patient in this family presented neurological manifestations consisting of polyneuritis and papilloedema, which were dissimilar to those of the patients seen in the reported families. The clinical manifestations of this patient resemble the Guillain-Barre syndrome except for the very chronic evolution of the symptoms. The lack of neurological symptoms in other members of this family suggested that the neurological manifestations of the propositus could be a fortuitous association and that only the unusual chronic evolution of the symptoms was related to the hypo-β-lipoproteinaemia. However, it cannot be excluded also that the neurological manifestations were a direct consequence of the familial metabolic error.