Impact of long-term immunosuppression with cyclosporin A on serum lipids in stable renal transplant recipients.

To determine the impact of long-term immunosuppression on serum lipids in stable renal graft recipients we measured serum lipids and apolipoprotein B concentrations in 20 patients receiving therapy with cyclosporin (CsA) and low-dose prednisolone (CsA/P) and in 18 patients on therapy with azathioprine and maintenance steroids (Aza/P). The patients were matched for age, body mass index, primary renal disease and dose of prednisolone, but not for the duration in transplantation and serum creatinine concentration. Triglyceride concentrations were significantly higher in the CsA/P group than in Aza/P-treated patients: 2.62 +/- 0.35 vs 1.62 +/- 0.23 mmol/l (P less than 0.05). Similarly, total cholesterol (C) levels were significantly more elevated in the CsA/P recipients than in the other group: 7.44 +/- 0.32 vs 5.84 +/- 0.25 (P less than 0.02). CsA/P patients had higher serum levels of LDL-C (4.79 +/- 0.20 vs 3.43 +/- 0.19 mmol/l (P less than 0.001) and apolipoprotein B concentrations (191 +/- 13 vs 128 +/- 9 mg/dl: P less than 0.001). CsA/P and Aza/P recipients had similar concentrations of HDL-C (1.73 +/- 0.13 vs 1.52 +/- 0.09 mmol/l: NS). We conclude that in stable renal graft recipients with good transplant function long-term immunosuppression with CsA/P is associated with a more atherogenic lipid status than therapy with Aza/P.

Competitive enzyme-linked immunosorbent assay (ELISA) for the quantitation of apolipoprotein A-I using a monoclonal antibody.

A semi-automated competitive enzyme-linked immunosorbent assay for human plasma apolipoprotein (Apo) A-I has been developed which utilizes nondelipidated samples, microtiter plates, commercially available monoclonal antibodies and alkaline phosphatase conjugated second antibody. The working range of the assay is 5-100 ng of Apo A-I. The range of plasma concentrations for plasma Apo A-I was 1.21 +/- 0.34 g/l for a random sample of 40 healthy adults. Intra- and inter-assay coefficients of variation (CV) were 4 and 7%, respectively. There was a good correlation between this assay and a radial immunodiffusion assay (r = 0.96). The assay is suitable for measurement of apolipoprotein A-I in either normal or pathological plasma, lipoprotein density classes, and for cell biological and molecular biological investigations.

Donor splice site mutation in the apolipoprotein (Apo) C-II gene (Apo C-IIHamburg) of a patient with Apo C-II deficiency.

The DNA, RNA, and protein of apo C-II have been analyzed in a patient with apo C-II deficiency (apo C-IIHamburg). Markedly reduced levels of plasma and intrahepatic C-II apolipoprotein were demonstrated by immunoblotting and immunohistochemical analysis. Northern, slot blot, and in situ hybridization studies revealed low levels of a normal-sized apo C-II mRNA. No major rearrangement of the apo C-II gene was detected by Southern blotting. Sequence analysis of apo C-II genomic clones revealed a G-to-C substitution within the donor splice site of intron II. This base substitution resulted in the formation of a new Dde I and loss of a Hph I restriction enzyme cleavage site. Amplification of the mutant sequence by the polymerase chain reaction and digestion with Dde I and Hph I restriction enzymes established that the patient was homozygous for the G-to-C mutation. This is the initial report of the DNA sequence of an abnormal apo C-II gene from a patient with deficiency of apo C-II. We propose that this donor splice site mutation is the primary genetic defect that leads to defective splicing and ultimately to an apo C-II deficiency in this kindred.

Apolipoprotein C-II deficiency: identification of a structural variant ApoC-II Padova.

Apolipoprotein(apo) C-II DNA, RNA and protein from a patient with a familial deficiency of apoC-II were evaluated and compared to normal individuals. No major defect of the apoC-II gene could be detected by Southern blot hybridization. Northern and slot blot analyses of total liver RNA documented normal levels of a normal sized apoC-II mRNA. Immunohistochemical studies of the liver of the apoC-II deficient patient revealed a normal to slightly elevated intracellular content of the C-II apolipoprotein. Plasma apoC-II was 3 to 5% of normal apoC-II levels and exhibited abnormal electrophoretic mobility on two dimensional gel electrophoresis and immunoblotting. We postulate that at the molecular level, the deficiency of apoC-II in the plasma of this patient results from a structural defect in the coding portion of the apoC-II gene leading to either defective secretion of cellular apoC-II or increased catabolism of a structurally defective apoC-II in plasma.

Comparison between simvastatin and bezafibrate in effect on plasma lipoproteins and apolipoproteins in primary hypercholesterolaemia.

The ability of simvastatin, a competitive inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase, to lower lipid levels in 16 patients with primary hypercholesterolaemia was compared with that of bezafibrate in a 16-week, double-blind, parallel, placebo-controlled trial that was continued in an open crossover fashion. Simvastatin was better than bezafibrate at lowering total and low-density lipoprotein (LDL)-cholesterol and apolipoprotein B concentrations (30.4% [p less than 0.001], 37.3% [p less than 0.001], and 37.8% [p less than 0.001] vs 17.0%, 19.6%, and 24.0%, respectively). Both drugs increased the high-density lipoprotein (HDL)-cholesterol and apolipoprotein A-I, but this change was significant only with bezafibrate (p less than 0.05). Bezafibrate and simvastatin reduced triglycerides by 25.6% (p less than 0.001) and 13.7% (p less than 0.05), respectively. Very low-density lipoprotein (VLDL)-cholesterol was significantly reduced only by bezafibrate (44.3%, p less than 0.001). Both drugs were tolerated well and no serious side-effects were noted. The results show that simvastatin was more effective than bezafibrate in lowering total-cholesterol, LDL-cholesterol, and apolipoprotein B, while bezafibrate was better at lowering triglycerides and VLDL-cholesterol and at raising HDL-cholesterol and apolipoprotein A-I.

Semi-automated enzyme-linked immunosorbent assay (ELISA) for the quantification of apolipoprotein B using monoclonal antibodies.

A semi-automated competitive, double-antibody, solid-phase enzyme-linked immunosorbent assay for apolipoprotein B (Apo B) has been developed which utilizes microtiter plates with commercially available monoclonal antibodies and alkaline phosphatase-conjugated second antibody. The working range of the assay is 20-200 ng. The concentration of plasma Apo B was 0.88 +/- 0.20 g/l (n = 40) for a random sample of normal adults. The correlation coefficient for this assay, compared to a radial immunodiffusion assay, was 0.95 (slope = 1.13, intercept = -15). The quantification of the samples was not influenced by freezing and thawing, storage at -20 degrees C for up to 9 mth, or the lipoprotein particle on which the Apo B was present. The method is suitable for measurement of apolipoprotein B in either normal or pathological plasma, lipoprotein density classes, and is sensitive enough to quantify Apo B in cell biological and molecular biological investigations.

Effectiveness of mevinolin on plasma lipoprotein concentrations in type II hyperlipoproteinemia.

Patients with low-density lipoprotein (LDL) concentrations in the top 10th percentile of the population (type II hyperlipoproteinemia [HLP]) are at increased risk for premature cardiovascular disease; however, the incidence of myocardial infarction and death can be decreased by LDL cholesterol reduction. Mevinolin, an inhibitor of endogenous cholesterol synthesis, has been shown to reduce LDL cholesterol concentrations in a subset of type II patients with heterozygous familial hypercholesterolemia (FH). Using a double-blind, randomized, crossover, placebo-controlled trial, the safety and efficacy of mevinolin were compared in 24 patients with type II HLP with heterozygous FH (n = 6) or without FH type II HLP (n = 18). Compared with placebo treatment, both apolipoprotein B and LDL cholesterol levels were reduced (p less than 0.01) in both FH and non-FH patients by 28 to 34% with mevinolin treatment. In addition, high-density lipoprotein cholesterol levels were significantly increased (p less than 0.001) in both patients with FH (16%) and those with non-FH type II HLP (14%). Patients had no serious or clinically significant adverse effects. Thus, mevinolin is a useful drug for treatment of most patients with elevated plasma LDL cholesterol concentrations.

Liver 3-phosphoglycerate kinase. Physico-chemical characterization of the bovine-liver enzyme.

Homogeneous phosphoglycerate kinase from bovine liver possesses a maximum ultraviolet absorption at 278 nm (A 1%,1Cm 280 equals 6.7; Amax/Amin equals 2.26; e280 equals 31.5 mM(-1) X cm(-1). The enzyme consists of about 420 amino-acid residues and is a slightly acidic protein with an isoelectric point of 6.5 as expected from amino-acid analysis. The most notable features of the chemical composition are two tryptophan, 12 methionine and four half-cystine residues per enzyme molecule. Although phosphoglycerate kinases from mammalian tissues are partially similar to each other, clear differences in serine, glutamic acid, glycine, cysteine, valine, leucine, tyrosine, tryptophan and arginine contents were found. Fingerprinting and column chromatography of tryptic digests of the S-carboxymethylated protein confirm the data of amino-acid analysis. Liver phosphoglycerate kinase is inactivated when modified with either p-chloromercuribenzoate or 5,5'dithio-bis(2-nitrobenzoic acid) (Nbs2). The enzyme has two thiol groups available for reaction with Nbs2 under denaturing conditions, one of which is essential for catalysis. After reduction by NaBH4 four cysteine residues per molecule were determined with Nbs2, sugessting the presence of a disulfide bridge. Using sedimentation equilibrium studies, the molecular weight was found to be 49600. Gel filtration yielded values of 43000-50000. By analytical dodecylsulfate-polyacrylamide gel electrophoresis a molecular weight of 45600 was estimated. Inconsistent with these results in the value 37500 obtained by thin-layer gel chromatography in 6 M guanidine-HCl. Sedimentation velocity experiments revealed a sedimentation coefficient s20,w equals 3.4 S. The Stokes radius was 2.77 nm, the partial specific volume v 0.747 ml x g(-1). The diffusion coefficient was found to be 76.9 mum2 x s(-1) by analytical gel filtration. From these data a molecular weight of 44000 was calculated. Other physical constants of bovine-liver phosphoglycerate kinase are: frictional ratio f/f0 equals 1.18, axial ratio equals 3.3, maximal degree of hydration equals 0.1 g per g of protein. Bovine-layer phosphoglycerate kinase could not be dissociated into smaller subunits by treatments which have caused dissociation of various other proteins (8 M urea, 6 M guanidine-HCl, dodecyl sulfate, carboxymethylation, maleylation). All experiments strongly support the lack of subunit structure of the enzyme. Some characteristics of bovine-liver phosphoglycerate kinase are compared with the corresponding proteins from rabbit muscle, yeast and human erythrocytes.