Plasma antioxidants and lipid peroxidation products in Duchenne muscular dystrophy.

Lipid peroxidation (LPX) products in plasma were elevated in Duchenne muscular dystrophy (DMD) patients (n = 9) compared with an age- and sex-matched group of controls (n = 10). Trichloroacetic acid-precipitable thiobarbituric acid-reactive substances (TBARS) were increased by 35% (p less than 0.01), conjugated dienes by 77% (p less than 0.02) and fluorescent pigments (FP) by 70% (p less than 0.001). Plasma alpha-tocopherol was significantly decreased, by 50%, in DMD compared with healthy subjects (p less than 0.002). In conjunction with the finding of others of a deficiency in DMD of the plasma lipoproteins which normally transport vitamin E to the tissues, this may contribute to the increased LPX seen in the disease especially if muscle damage also liberates free Fe2+. The major circulating antioxidant protein, caeruloplasmin (CP), was significantly increased (p less than 0.001) by 25-30% in DMD patients compared with both adult and young male controls. In DMD patients only, this increase is correlated with the concentration of TBARS and FP suggesting that increased LPX may be a trigger for CP synthesis.

Lipid peroxidation products and antioxidant proteins in plasma and cerebrospinal fluid from multiple sclerosis patients.

Lipid peroxidation (LPx) products were measured as thiobarbituric acid-reactive substances (TS) and lipid-soluble fluorescent pigments (FP) in both plasma and CSF from MS patients and controls. Although no significant changes were found in MS plasma, we report here for the first time increases in both TS and FP in MS CSF (p less than 0.05 and p less than 0.01, respectively, compared with patients with other neurological diseases), indicating that increased LPx in CNS may be a feature of MS. Levels of transferrin were normal but caeruloplasmin (CP), a major antioxidant plasma protein, was significantly raised in MS patients (p less than 0.01) and this may represent an adaptive response to increased oxidative challenge. Neither of these proteins was detectable in CSF using radial immunodiffusion. There was no significant correlation between the severity or duration of the disease nor the period since the last relapse and either LPx products or CP suggesting that the changes observed in this work are not simply the direct result of demyelination and tissue damage.

Erythrocyte antioxidant enzymes in multiple sclerosis and the effect of hyperbaric oxygen.

The activities of catalase, glutathione peroxidase, and glutathione reductase, were not significantly different from normal whereas that of superoxide dismutase was decreased (P less than 0.05) in erythrocytes from patients with multiple sclerosis. Assay of the lipid peroxidation product, malondialdehyde, after incubation of erythrocytes with 10 mM H2O2 under carefully controlled conditions (peroxide stress test) demonstrated that MS erythrocytes are significantly (P less than 0.001) less susceptible to H2O2-induced lipid peroxidation in vitro. This finding suggests that the level of an endogenous antioxidant, possibly vitamin E, may be elevated in MS red cells. After treatment with hyperbaric O2, the activity of MS erythrocyte catalase is significantly (P less than 0.01) elevated by 2-6-fold.

Erythrocyte membrane glycerophospholipid organization is normal in multiple sclerosis.

The phospholipid composition of erythrocyte membranes from patients with multiple sclerosis (MS) was found to be normal, in agreement with previous reports. The transbilayer asymmetry of the glycerophospholipids in MS red cells was probed using bee venom phospholipase A2 and was also found not to be significantly different from normal. Abnormal membrane glycerophospholipid organisation is therefore not involved in the increased red cell size, osmotic fragility, and electrophoretic mobility associated with MS.

Is erythrocyte membrane phospholipid organisation abnormal in Duchenne muscular dystrophy?

Many of the abnormalities reported in erythrocytes from Duchenne muscular dystrophy (DMD) patients, including alterations in the physical state of the membrane as determined by electron spin resonance, could arise from changes in the lipid components. Although several investigators have shown there to be no compositional differences between normal and DMD erythrocytes, there still exists the hitherto unexplored possibility that the normal asymmetric organisation of the lipids may be deranged in the disease. This report is concerned with the probing of the asymmetric transbilayer distribution of the glycerophospholipids using phospholipase A2 from bee venom. Our results suggest that more phosphatidyl choline (PC) is available for attack by the enzyme in the outer leaflet of the bilayer in DMD erythrocytes than in normals. This may be due to a greater than normal proportion of the PC being present in the outer leaflet or to enhanced transbilayer movement of PC molecules from the inner leaflet. Whichever the explanation, these findings indicate an organisational abnormality in DMD erythrocyte membranes.

The effect of temperature on the growth and lipid composition of the extremely halophilic coccus, Sarcina marina.

Sarcina marina (NCMB 778) grew over the temperature range 20-45 degrees C but no growth was recorded at 15 degrees C or 50 degrees C. At the optimum growth temperature of 34 degrees C the doubling time was 14.5 h. The major polar lipid components, tentatively identified as the diether analogues of phosphatidyl glycerophosphate (PGP), phosphatidyl glycerol (PG), diglycosyl diglyceride (DGD) and triglycosyl diglyceride (TGD), and the major neutral lipid components, tentatively identified as squalene, dihydrosqualene, tetrahydrosqualene, vitamin MK8, geranyl geraniol and di-O-phytanyl glycerol, are identical to those found in other extremely halophilic rods and cocci. The total lipid content varied with growth conditions from 0.6-3.2% of the dry cell weight, polar lipids accounted for between 94.3 and 83.6% of the total lipid, the remainder being neutral lipid. In response to both the transition from exponential to stationary phase and a reduction of 14 degrees C in growth temperature, batch cultures showed: (i) an increase in total lipid content; (ii) a decrease in PG and (iii) an increase in PGP. Specific responses to the temperature decrease were (i) increased total lipid content; (ii) no decrease in neutral lipids in stationary phase; (iii) marked reduction in PG and (iv) raised DGD. (i) and (ii) could be mechanisms for increasing membrane fluidity. In common with all other extreme halophiles investigated the alkyl side chains of S. marina polar lipids were identified as the phytanyl (3R, 7R, 11R, 15-tetramethylhexadecyl) group. Its structure did not appear to vary with temperature so that the normal mechanisms for modifying the structure of lipid alkyl side chains to modulate membrane fluidity in response to temperature changes probably does not occur in this group of microorganisms.

Superoxide dismutase, glutathione peroxidase and thiobarbituric acid-reactive compounds in erythrocytes in Duchenne muscular dystrophy.

The activities of erythrocyte superoxide dismutase and glutathione peroxidase in patients with Duchenne muscular dystrophy were normal compared with healthy male controls, as were the levels of thiobarbituric acid-reactive compounds produced during incubation of erythrocytes in the presence of 10 mmol.1-1 hydrogen peroxide. These results suggest that the chief mechanisms for protecting the erythrocyte membrane from peroxidative damage are unimpaired and do not support the idea that the reported erythrocyte abnormalities in this disease result from increased susceptibility to lipid peroxidation.

Effect of lysozyme treatment on cell wall ultrastructure in Sarcina flava.

Treatment of Sarcina flava NCTC 7503 cells with lysozyme resulted in incomplete removal of the cell wall and imparted a layered appearance to it.