[Proton magnetic resonance of plasma in the evaluation of systemic effects of cutaneous inflammation in rats].

NMR evaluation of skin rat inflammation, 24 h after UVB exposition and 48 h after vesicatory (croton oil) application, shows significant variations of relaxation times. Cutaneous T1 and T2 are enhanced in both cases, and plasmatic T2 is increased in croton oil inflammation. At the same time, these two inflammations induce in plasma: a significant increase in ceruloplasmin (respectively 70 and 42%); a decrease in iron transferrin (48 and 53%) and iron saturation (%) of transferrin (53 and 68%); an increase in the protein level of 45% for croton oil treated animals.

Glutaryl phosphatidylcholine effects on pH and composition dependent behavior of liposomes studied by spin-labeling method.

The influence of glutaryl phosphatidylcholine on the molecular organization of phosphatidylcholine liposomes was studied by spin-labeling technique. The ESR signals given by the 5-nitroxide stearic acid label showed that the presence of glutaryl lecithin (i) significantly increased the negative charge density of the polar liposome surface with increasing proton concentration depending on the bulk solution pH, and (ii) apparently decreased the packing (order) of the hydrophobic region close to the surface, essentially in the presence of saturated phospholipids. The spectral information--S (order parameter) and alpha N (isotropic nitrogen coupling constant)--resulted in the location of the probe near or in the polar zone of the membrane or in the hydrophobic region, depending on the protonation/deprotonation of the fatty acid carboxyl group of the probe.

Thermodynamic interpretation of effects of alcohols on membrane lipid fluidity.

The effect of a series of amphiphilic compounds, the first eight n-aliphatic alcohols, on the fluidity of rat enterocyte brush border was determined by ESR using 5-doxyl stearic acid as a lipid spin probe. Packing order variations are compared to the relative hydrophobic effect of the alcohols. The concentrations, [Ci]5 of each alcohol that decrease the membrane 2T' value by 5%, vary by a factor of 1500 from methanol to octanol.

Covalent attachment of insulin to the outer surface of liposomes.

We describe a method for covalent binding of insulin to the outer surface of multilamellar liposomes loaded with spin label. Encapsulation of the label Tempocholine-nitroxide within the aqueous phases of liposomes is controlled by Electron Spin Resonance. The binding of insulin is performed using the Carlsson's heterobifunctional reagent: N-succinimidyl 3-(2-pyridyldithio) propionate.