Duchenne muscular dystrophy: alterations in lymphocyte fluidity.

We have studied lymphocyte membrane from 7 patients with Duchenne Muscular Dystrophy (DMD) and 8 normal controls using fluorescence polarization of 1,6-diphenyl-hexatriene (DPH). The microviscosity of lymphocytes membrane is significatively higher in DMD patients than in normal controls. Our results support the hypothesis of a generalized membrane defect in Duchenne Muscular Dystrophy.

The intrinsic fluorescence characteristics of sarcoplasmic reticulum membranes.

The fluorescence characteristics of tryptophan in sarcoplasmic reticulum, were investigated to gain information concerning its location and environment within the intact membrane system. With an excitation of 295 nm, tryptophan has an emission maximum of 330 nm characteristic of tryptophan in a buried hydrophobic environment. At the wavelength studied only a faint contribution of tyrosine is present. The changes observed in the presence of urea 8 M suggest only a partial exposition of the aromatic residues.

[Molecular organization of erythrocyte membranes in Duchenne muscular dystrophy]. / Studi sulla organizzazione molecolare della membrana eritrocitaria nella distrofia muscolare Duchenne.

Lipid-soluble spin labels were used to study lipid protein interactions in erythrocyte membranes obtained from patients with Duchenne muscular dystrophy. The temperature dependence of order parameter (Sn) and correlation time (tau c) have demonstrated alterations in the surface and in the hydrophobic core of membrane; the differences might be correlated with a depletion of extrinsic protein and of intramembrane particles. Our studies suggest a great abnormality of membrane molecular organization in Duchenne muscular dystrophy.

[Study of lipid-protein interactions in mitochondrial membranes using the intrinsic fluorescence of tryptophan]. / Studio delle interazioni lipidi-proteine in membrane mitocondriali mediante l'uso della fluorescenza intrinseca del triptofano.

The environment of membrane-bound proteins has been investigated by measuring the fluorescence of intrinsic tryptophans in intact bovine heart mitochondria, in lipid-depleted mitochondria, and in reconstituted mitochondria. Lipid depletion induces a strong decrease of fluorescence intensity, probably as the result of extraction of peripheral proteins by the solvents used. Comparison of lipid-depleted and lipid-reconstituted mitochondria shows a higher fluorescence in the lipid-depleted membranes; in an Arrhenius plot the fluorescence intensity shows two breaks in the lipid-depleted membranes, but no break in the reconstituted ones. Butanol has little effect on fluorescence intensity of intact mitochondria. The results are compatible with a constant lipid environment of integral proteins which is not modified by either temperature or organic solvents.