Plasma anti-proteases in Duchenne muscular dystrophy

Elevated plasma levels of haptoglobin in Duchenne muscular dystrophy:electrophoretic variants in patients with a severe form of the disease

Analysis of plasma proteins of Duchenne muscular dystrophy (DMD) patients and normal age-matched boys using two dimensional gel electrophoresis and densitometry indicated a three-fold increase in the average haptoglobin level in DMD plasma. Two electrophoretic variants of haptoglobin in which the alpha 2 chain had more basic or more acidic spots were found in DMD patients with a rapidly progressing form of the disease. The basic variant was present in relatively low amount. Possible reasons for the elevated haptoglobin levels are discussed.

Serum activity of C1 inactivator in Duchenne-type progressive muscular dystrophy

We previously found that the level of the immunoreactive activity of C1 inactivator in the plasma Duchenne-type patients with progressive muscular dystrophy was lower than that in normal boys. Therefore, we investigated the level of the C1 inactivator inhibiting activity against C1 esterase in the serum from PMD patients. The mean level of anti-esterase activity of C1 inactivator against C1 esterase in the serum from PMD was 50% lower than that of the control group (P less than 0.05).

Some biophysical properties of the erythrocyte membrane in Duchenne muscular dystrophy

Inasmuch as prior authors have suggested a 'generalized membrane defect' in patients with Duchenne muscular dystrophy, this study was undertaken to examine some biophysical properties of the erythrocytes in affected individuals. Using the micropipette technique we investigated the rheological properties of erythrocytes from 11 Duchenne muscular dystrophy patients (boys 3-14 years old) and 5 carriers (mothers 20-42 years old). The mean elastic modulus and membrane viscosity of the patient's erythrocytes were not significantly different from those of a group of 8 unaffected age-matched boys. The carrier group did not differ significantly from the adult control group in any of the rheological parameters. A significant increase in the number of stomatocytes was observed in the patient group, and a similar trend (not statistically significant) was observed in the carrier group. The membrane lipid fluidity of erythrocytes from patients, carriers, and normal controls was assessed with three different probes by fluorescence depolarization, and no significant differences were found. Our results indicate that there is a progressive elevation of the membrane elastic modulus with increasing age of the patients: the younger patients have a lower elastic modulus than their age-matched controls, while the older patients have a higher elastic modulus than their age-matched controls.

Plasma plasmin inhibitors in Duchenne-type progressive muscular dystrophy

In our previous research, we found that the level of the plasminogen activity in the plasma from Duchenne-type patients with progressive muscular dystrophy was higher than of the normal boys, though the level of the plasmin inhibitors was lower. Therefore, in the present study, we investigated the differences in the fractions of plasmin inhibitors. The subjects were nine patients (the average age being 17.1 years) who had been diagnosed, by clinical and biochemical tests, as having PMD; serving as controls were normal boys (the average age being 15 years), the patients' mothers, and the mothers of the normal boys. The plasmin inhibitors were separated from plasma using lysine-Sepharose columns according to the method of Urita et al. The determination was performed based on the method of Aoyagi et al. and an immunoreactive assay. The results were as follows: (1) No significant differences were seen between patients with PMD and control subjects with respect to either alpha 1-antichymotrypsin, antithrombin III, and alpha 1-antitrypsin or alpha 2-macroglobulin and inter-alpha-trypsin inhibitors. These results suggested that the low level of plasmin inhibitors in patients was due to the low activity of the C1 inactivator. (2) The patients with PMD showed lower values than the normal boys in the levels of C1 inactivator in plasma; similarly, the mothers of these patients showed lower values than the normal mothers.