1/5. Response to diet and cholestyramine in a patient with sitosterolemia.In this report, an 11-year-old boy with diffuse tendinous and tuberous xanthomatosis and a plasma sterol concentration of 555 mg/dL, consisting primarily of cholesterol, is described. Three months after changing from an unrestricted diet to a cholesterol-lowering diet, his plasma sterol concentration decreased to 221 mg/dL. Because of the degree and rapidity of his response to diet, sitosterolemia was suspected. According to results of capillary gas-liquid chromatography of his plasma sterols, there was a sitosterol concentration of 31.3 mg/dL (normal less than 1.0 mg/dL), establishing the diagnosis of sitosterolemia. Addition of cholestyramine therapy (8 g/d) to a low sterol diet further lowered his plasma sterol concentration to 173 mg/dL and led to complete regression of all tuberous xanthomata. Tendinous xanthomata regressed at a slower rate. These findings show that the diagnosis of sitosterolemia should be suspected in severely hypercholesterolemic children (total cholesterol greater than 400 mg/dL) whose plasma cholesterol level is highly responsive to dietary manipulation. The rapid and sustained lowering of plasma cholesterol and regression of xanthomata after treatment with diet and cholestyramine suggest that sitosterolemia is a treatable cause of premature atherosclerosis.- - - - - - - - - - ranking = 1keywords = chromatography (Clic here for more details about this article) |
2/5. autoantibodies to the low density lipoprotein receptor in a subject affected by severe hypercholesterolemia.We studied a 32-yr-old man with a benign paraproteinemia (IgA) affected by severe nonfamilial hypercholesterolemia. in vitro experiments demonstrated that lipoprotein-deficient serum (LPDS) from the patient inhibited the binding of low density lipoprotein (LDL) to human skin fibroblasts cultured in vitro (up to 70%) whereas LPDS from controls had no effect. Removal of IgA from the patient's serum by immunoprecipitation with mono-specific antisera abolished the inhibition of LDL binding. IgA isolated from the serum of the patient by affinity chromatography inhibited, in a dose-dependent manner, the binding of LDL to human skin fibroblasts in vitro, thus showing an IgA-mediated effect. Ligand-blotting experiments demonstrated that the paraprotein directly interacts with the LDL receptor, thus inhibiting the binding of the lipoprotein. Treatment of the receptor protein with reducing agents blocked the interaction of the antibody with the LDL receptor. From these data we speculate that this autoantibody may be responsible for the severe nonfamilial hypercholesterolemia of the patient.- - - - - - - - - - ranking = 1keywords = chromatography (Clic here for more details about this article) |
3/5. Marked hyper-HDL2-cholesterolemia associated with premature corneal opacity. A case report.We report here a peculiar case with premature corneal opacity and extremely high levels of HDL cholesterol in serum. The patient is a 54-year-old man who was first noticed to have marked corneal opacities at age 19. His serum HDL cholesterol level was elevated to the level of 135-160 mg/dl, while total serum cholesterol and triglyceride concentrations were 254 mg/dl and 56 mg/dl, respectively. serum apoprotein A-I and E levels analyzed by single radial immunodiffusion method were elevated in the case. serum lipoprotein fractions isolated by preparative ultracentrifugation revealed that increased levels of HDL cholesterol were accounted for solely by the HDL2 fraction. HDL2 of the patient contained relatively higher amounts of apoprotein E than normal control HDL2. Elution profiles of lipoproteins in high performance liquid chromatography revealed that HDL2 particles from the patient were larger in size than those from normal controls. These characteristics of HDL are in part similar to those of HDLC which appears in experimental animals after cholesterol feeding. Such abnormalities in HDL2 fractions associated with premature corneal opacity have not been reported so far and appear to constitute a new disease entity.- - - - - - - - - - ranking = 1keywords = chromatography (Clic here for more details about this article) |
4/5. A new approach to the management of familial hypercholesterolaemia: Removal of plasma-cholesterol based on the principle of affinity chromatography.Reduction of plasma-cholesterol by the removal of low-density lipoproteins (L.D.L.) in an extracorporeal system is described as a possible approach in the treatment of familial hypercholesterolaemia. L.D.L. were removed from the blood by their interaction with heparin linked to agarose beads in the presence of calcium ions. plasma-L.D.L. was markedly decreased in two patients with heterozygous familial hypercholesterolaemia. The technique is specific for the removal of L.D.L., as the concentration of high-density lipoproteins was not affected. The treatment was well tolerated by all three subjects (i.e., two hypercholesterolaemic patients and a normal volunteer), and there were no undesirable effects. Several haematological parameters, clinical-chemistry tests, including serum enzymes, and immunoelectrophoresis of plasma proteins were all unaffected by the treatment.- - - - - - - - - - ranking = 4keywords = chromatography (Clic here for more details about this article) |
5/5. Profile of urinary bile acids in familial intrahepatic cholestasis with Coombs' negative haemolytic anaemia.We present two male siblings with intrahepatic cholestasis and prolonged indirect hyperbilirubinaemia. Their familial intrahepatic cholestasis syndrome was characterized by Coombs' negative haemolytic anaemia, without giant cell transformation of hepatocytes and high concentrations of serum gamma-glutamyl transpeptidase and cholesterol. By gas chromatography-mass spectrometry, we detected large amounts of 1 beta-hydroxylated bile acids, especially 1 beta,3 alpha,7 alpha,12 alpha-tetrahydroxy-5 beta-cholan-24-oic acid (25.5-67.9% of total urine bile acids) in the urine during phenobarbital therapy. However, the amount of urinary 1 beta-hydroxylated bile acids gradually decreased as the disease progressed. At the end-stage, we detected large amounts of 7 alpha,12 alpha-dihydroxy-3-oxochol-4-en-24-oic acid (19.6% of total urine bile acids). The ratio of 7 alpha,12 alpha-dihydroxy-3-oxochol-4-en-24-oic acid to cholic acid in the urine was 0.8. We conclude that in infants with end-stage liver failure, the microsomal hydroxylation of bile acids is impaired and the excretion of delta 4-3-oxo bile acids is increased.- - - - - - - - - - ranking = 1keywords = chromatography (Clic here for more details about this article) |