[The cost in calculating transport noise disturbances in public decision making]

The public decision-making methods in transport are based on cost-benefit analysis, by which the consequences of the decision (standards for vehicles, new infrastructures...) are converted in monetary amounts and compared to the cost of implementation of the decision. But some of these consequences, especially those related to environment, are not directly expressed in monetary terms. The article aims at offsetting this difficulty in the case of noise. The possible methods for getting money values of noise are presented; it is shown that the estimates to which they lead are coherent and consistent. Then a comparison is made between the present procedures and the procedures which could be implemented, and it is shown that large gains of efficiency could be obtained.

Effects of 2-(substituted-sulfanyl)-3,5-dihydro-imidazole-4-one and 2-(substituted-sulfanyl)-1H-imidazole-4,5-dione derivatives on serum HDL-cholesterol

A series of 2-substituted sulfanyl-3,5-dihydro-imidazole-4-ones and 2-substituted sulfanyl-1H-imidazole-4,5-diones was prepared and shown to increase high density lipoprotein cholesterol over other lipid fractions. Compound 1f showed efficacy in additional animal models. The major metabolite of 1f was isolated and its synthesis is reported. The effects of the metabolite on the lipid profile in rats were investigated.

Inhibition of the cellular secretion of cholesteryl ester transfer protein by a variant protein formed by alternative splicing of mRNA

Alternative splicing of mRNA is often used as a regulatory switch, determining whether a functional protein is made or not. The plasma cholesteryl ester transfer protein (CETP) mediates the transfer of cholesteryl esters from high density lipoproteins to other lipoproteins. In addition to the mRNA encoding plasma CETP, human tissues contain an alternatively spliced variant in which exon 9-derived sequences are omitted. To determine a possible regulatory role of alternative splicing, COS cells were co-transfected with full-length and exon 9-deleted cDNAs. The exon 9-deleted protein was poorly secreted and inhibited the secretion of full-length CETP, due to formation of an intracellular heteromeric complex between full-length and exon 9-deleted proteins. The findings suggest a novel use of alternative splicing to generate a poorly secreted protein variant, which complexes with the active form and prevents its secretion by cells.

Cholesteryl ester transfer protein and high density lipoprotein responses to cholesterol feeding in men: relationship to apolipoprotein E genotype

The apolipoprotein (apo) E isoform is an important determinant of the plasma lipoprotein distribution of apoE and of the metabolism of apoE-containing lipoproteins. We have determined the effects of apoE genotype on the plasma lipoprotein response to cholesterol feeding in 30 young normal male subjects (5 E3/2, 11 E3/3, 14 E4/3) under rigorously controlled dietary conditions. Two diets, differing only in cholesterol content (low cholesterol (LC): 80 mg cholesterol/1000 kcal and high cholesterol (HC): 320 mg cholesterol/1000 kcal), were compared using a random crossover design. At the end of the HC as compared to the LC period, total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C), and HDL2-C increased by an average of 15%, 21%, 7%, and 23%, respectively, for the three genotype groups combined (P < 0.001 for each). The LDL-C response to dietary cholesterol did not differ among the apoE genotypes. However, the increase in HDL-C varied significantly according to the apoE genotype (E3/2: 0 change, E3/3: +4%, E4/3: +12%; P < 0.05). The plasma cholesteryl ester transfer protein (CETP) response to cholesterol feeding also differed amongst the three apoE genotype groups (E3/2: +37%, E3/3: +18%, E4/3: +9%) (P < 0.05). ApoE genotype has significant and opposite effects on plasma CETP and HDL-C responses to dietary cholesterol in men.

Plasma lipid transfer protein as a determinant of the atherogenicity of monkey plasma lipoproteins

This study was undertaken to determine potential tissue sources of plasma cholesteryl ester transfer protein (CETP), and to assess the influence of CETP on lipoprotein concentrations and atherosclerosis. In a group of 28 cynomolgus monkeys fed high fat, high cholesterol diets, plasma CETP concentration was strongly correlated with the abundance of CETP mRNA in liver and in adipose tissue, and with the output of CETP in liver perfusates. Plasma CETP concentration showed a strong inverse correlation with HDL cholesterol concentrations (r = -0.62, P less than 0.001) and a positive correlation with LDL cholesterol concentration (r = 0.54, P less than 0.005) and molecular weight (r = 0.57, P less than 0.001). The extent of coronary artery atherosclerosis was positively correlated with LDL cholesterol concentration and molecular weight, and with plasma CETP concentration. Thus, in monkeys fed an atherogenic diet, individual variation in CETP mRNA abundance in liver and adipose tissue probably plays a major role in the determination of plasma CETP levels. In plasma, CETP influences the distribution of cholesteryl esters between LDL and HDL, and CETP concentration appears to be a key determinant of the relative atherogenicity of the plasma lipoproteins.

Mammalian adipose tissue and muscle are major sources of lipid transfer protein mRNA

The plasma cholesteryl ester transfer protein (CETP) catalyzes the transfer of cholesteryl esters from high density lipoproteins (HDL) to triglyceride-rich lipoproteins and plays a major role in the catabolism of HDL. Lipoprotein lipase (LPL) is the rate-limiting enzyme for hydrolysis of circulating triglyceride and is involved in HDL formation. We show that tissues containing LPL are major sources of CETP mRNA in several mammalian species, including some with low cholesteryl ester transfer activity in plasma. In hamsters, adipose tissue and heart were found to be the richest sources of both CETP and LPL mRNA; in situ hybridization studies showed that the same cell types (i.e. adipocytes or myocytes) contained CETP and LPL mRNA in these tissues. Isolated adipocytes synthesized active CETP. Dietary studies revealed a complex pattern of response of CETP mRNA levels in different tissues, which showed partial similarity to the changes in LPL mRNA abundance. However, high cholesterol diets resulted in increased CETP mRNA abundance in adipose tissue, heart, and skeletal muscle, without equivalent changes in LPL mRNA. Plasma HDL cholesteryl ester levels showed strong inverse correlations with CETP mRNA abundance in adipose tissue. The results suggest a conserved function of CETP in adipose tissue and heart, such as a co-ordinate action with LPL to enhance HDL turnover. Although there is considerable overlap in the tissue- and cell-specific pattern of CETP and LPL gene expression, dietary studies revealed only limited parallelism in response at the mRNA level. The increase in CETP mRNA in peripheral tissues in response to increased dietary cholesterol suggests that local induction of CETP synthesis may help to recycle cholesterol deposited in these tissues during lipolysis of dietary lipoproteins.

Mechanism of cholesteryl ester transfer protein inhibition by a neutralizing monoclonal antibody and mapping of the monoclonal antibody epitope

The plasma cholesteryl ester transfer protein (CETP, Mr 74,000) has a binding site for neutral lipid which can readily equilibrate with lipoprotein cholesteryl esters or triglycerides. Recently, a monoclonal antibody (TP2) was obtained which neutralizes the cholesteryl ester (CE) and triglyceride (TG) transfer activities of the CETP. In this report, the epitope of the inhibitory monoclonal antibody has been localized to a hydrophobic 26-amino acid sequence at the COOH terminus of CETP. The Fab fragments of TP2 caused partial (50%) inhibition of CE transfer and complete inhibition of TG transfer by the CETP. Similarly, the Fab fragments inhibited (37%) the binding of CE to the CETP and abolished the binding of TG to the CETP. Surprisingly, the TP2 Fab was also found to enhance the binding of CETP to plasma lipoproteins and to phospholipid vesicles. In conclusion, the TP2 monoclonal antibody inhibits lipid transfer by blocking the uptake of lipid by CETP. The COOH-terminal epitope may be in or near the neutral lipid binding site. Occupancy of this site by TP2 Fab fragments or by neutral lipid may result in a conformational change of CETP causing enhanced binding to lipoproteins or vesicles.

Application of SDS gradient polyacrylamide slab gel electrophoresis to analysis of apolipoprotein mass and radioactivity of rat lipoproteins

An application of SDS gradient polyacrylamide slab gel electrophoresis to the analysis of lipoprotein polypeptides is described. The 10-15% polyacrylamide gradient provides a high degree of resolution and sensitivity resulting in a single separation of the major apoproteins which can be easily visualized. When combined with autofluorography, individual protein mass and radioactivity can be determined densitometrically while still retaining excellent resolution. Examples of rat lymph and plasma apolipoproteins are shown, and apparent heterogeneity of certain apoprotein subgroups is described.

Apolipoprotein localization and quantitation in the human intestine

Apolipoproteins B, A-I, and A-IV were localized in human intestinal epithelium using immunoperoxidase techniques. Staining was most obvious in villus tip cells. Lipid absorption resulted in an increase in intraepithelial staining for each apoprotein. The pattern for apo-B in the biopsy specimens taken after lipid absorption revealed a marked redistribution of staining to the intercellular spaces and an increase in the supranuclear staining of apo-A-I and apo-A-IV. After lipid absorption, staining appeared to extend further down the villus than in the fasting biopsy specimens. Quantitation of apo-A-I and apo-A-IV in isolated epithelial cells confirmed that the mass of these apoproteins increases in response to lipid absorption. Apolipoprotein B and apo-A-I were absent in the epithelium of 3 patients with abetalipoproteinemia while apo-A-IV was present in 2 patients. These studies demonstrate differences in the localization and quantitation of apoproteins in the villus-crypt unit as well as differences in the localization pattern of the different apoproteins.

Human apolipoprotein A-IV. Intestinal origin and distribution in plasma

The role of the human intestine has been explored as a site of synthesis of apoA-IV, a major apoprotein of human intestinal triglyceride-rich lipoproteins. Intestinal biopsies were performed on normal volunteers while fasting and after lipid ingestion. Indirect immunofluorescence demonstrated a marked increase in immunofluorescence for apoA-IV during lipid absorption consistent with an increased intracellular content. ApoA-IV comprised 10-13% of chylomicron apoprotein and 24-30% of intestinal very low density lipoprotein (VLDL) as assessed by densitometry of sodium dodecyl sulfate gels of lipoproteins from chylous urine (mesenteric lymphatic-urinary fistula) and thoracic duct lymph (postoperative fistula). After one subject with chyluria ingested 40 g of corn oil, triglyceride excretion in urine was accompanied by an increased excretion of apoA-IV. 11.5 g of triglyceride and 81 mg of apoA-IV were recovered in the urine. In chylous urine 56% of apoA-IV was in the triglyceride-rich lipoproteins (chylomicrons and intestinal VLDL) and 44% in the d > 1.006-g/ml fraction. Normal plasma apoA-IV was 15.7+/-0.9 mg/dl (n = 14) whereas four subjects with abetalipoproteinemia had reduced levels 1.2, 7.6, 9.6, and 8.3 mg/dl, respectively. Lipid feeding in normal volunteers resulted in a rise in plasma apoA-IV (16.1+/-0.7 mg/dl to 18.5+/-0.7 mg/dl, n = 5, P < 0.01). In fasting plasma, 98% of apoA-IV was in the d > 1.21-g/ml fraction. In lipemic plasma, 10% of apoA-IV was associated with triglyceride-rich lipoproteins and 90% with the d > 1.21-g/ml fraction. Agarose column chromatography of fasting plasma confirmed that the bulk of plasma apoA-IV is free, unassociated with lipoproteins. These results demonstrate that apoA-IV is present in human intestinal epithelial cells and is secreted as a chylomicron and VLDL apoprotein. Within fasting plasma most of the apoA-IV is found free, unassociated with lipoproteins. After lipid ingestion apoA-IV is also found in plasma chylomicrons indicating that some apoA-IV remains associated with chylomicrons in plasma during chylomicron metabolism, although some may be transferred from the chylomicron surface.