The degree of random orientation of excited diphenylhexatriene molecules in isolated erythrocyte membrane ghosts was investigated in order to determine the possible effect of lipid disorders on membrane structure in children suffering from type I diabetes mellitus with and without diabetic retinopathic lesions. A decrease of cholesterol in the antiatherogenic fraction HDL (1.17 +/- 0.06 in retinopathy vs 1.24 +/- 0.065 in controls) and its increase in atherogenic LDL fraction (3.88 +/- 0.23 vs 2.63 +/- 0.26) as well as developing erythrocyte membrane rigidization in diabetes and retinopathy (0.193 +/- 0.008 and 0.204 +/- 0.014 vs 0.161 +/- 0.008 in controls) were observed. Considerable fluctuations in plasma and membrane cholesterol:phospholipid ratio were most pronounced in subjects exhibiting diabetic background retinopathy. The content of membrane cholesterol compared significantly with both membrane fluidity (r = 0.677), cholesterol of LDL (r = 0.667) and cholesterol:phospholipid ratio in HDL (r = 0.693) which suggests a destructive effect of lipid disorders on cell membrane structure in diabetics.

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: It seems that hypervolemia and vasodilatation coincide in compensated cirrhosis, but neither rank nor importance of these factors has been fully clarified in adaptive response to postural change. We studied, with gated equilibrium radionuclide angiography and thoracic electrical bioimpedance the hemodynamic status of 19 patients with compensated cirrhosis and 18 healthy subjects in upright and supine positions. In the upright position, the cirrhotic patients were hypotensive and had decreased peripheral vascular resistance despite increased cardiac output. The transition to the supine position was accompanied by a significant fall in the heart rate and an increase in the stroke volume in both controls (92±22 to 63±10 beats/min, and 38±9 to 62±19 ml/m2, respectively) and cirrhotic patients (101±20 to 79±13 beats/min, and 44±15 to 63±19 ml/m2, respectively). Besides, the diastolic arterial pressure fell in controls from 89±9 mmHg to 81 ± 11 mmHg; p <0.01, while it remained unchanged in cirrhotic patients (77±17 vs 82±13 mmHg). In the supine position, the cirrhotic patients presented tachycardia and left ventricular hyperkinesy (increased velocity of left ventricular filling and emptying). In conclusion, these results show that in compensated cirrhosis the decreased arterial tone and peripheral blood pooling are important factors of adaptive hemodynamic reaction to postural change.

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