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Query: UMLS:C0020473 (hyperlipidemia)
 15,891 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of lipid lowering therapy (bezafibrate) on plasma lipoproteins was investigated in twelve patients with familial hypercholesterolaemia (type IIA) and eight with familial combined hyperlipidaemia (type IIB). Bezafibrate caused a decrease of plasma cholesterol, plasma triglycerides, plasma apolipoprotein B, VLDL cholesterol and LDL cholesterol and an increase of HDL cholesterol. Post-heparin plasma lipoprotein and hepatic lipase activities increased in both groups (significant only in type IIB). Lipoprotein composition showed the following changes: Increased protein and phospholipids and decreased triglycerides and cholesteryl esters in VLDL. Decreased protein and triglycerides and increased free and esterified cholesterol in LDL. Decreased triglycerides and increased phospholipids in HDL. Cholesteryl ester to protein ratios decreased in VLDL and increased in LDL. The hydrated density of LDL (both groups) and of HDL3 (type IIB) decreased following bezafibrate therapy. These changes were in general similar to those observed in hypertriglyceridaemic patients and could be ascribed, at least in part, to the increase of plasma lipase activities and the decrease of lipid transfer reactions. Comparing the present data with that previously reported, it was found that bezafibrate caused decreased LDL cholesterol in types IIA and IIB but increased levels in type IV. This change was correlated with the initial plasma triglycerides (r = 0.74, P less than 0.0001) and initial plasma LDL cholesterol (r = 0.66, P less than 0.001). It is concluded that varied response of LDL to therapy reflects a complex interaction of metabolic events, including changing rates of VLDL conversion to LDL, lipoprotein compositional changes and effects of therapy on LDL degradation rates.
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PMID:Change in very low-, low-, and high-density lipoproteins during lipid lowering (bezafibrate) therapy: studies in type IIA and type IIb hyperlipoproteinaemia. 308 75

Plasma lipolytic activity (lipoprotein lipase and hepatic lipase), free fatty acids (FFA), triglycerides, cholesterol, and glucose levels were measured in 21 premature infants [gestational age 26-37 weeks (mean +/- SEM 30.4 +/- 0.63 weeks), aged 1-8 days (mean +/- SEM 3.00 +/- 0.35 days)]. All infants were maintained on total parenteral nutrition with heparin (1 U/ml) and were given Intralipid, 1, 2, and 3 g/kg/day, over 15 h on days 1, 2, and 3, respectively. Blood samples were drawn before and at the end of Intralipid administration. Baseline plasma lipolytic activity, before the start of lipid infusion, was 1.54 +/- 0.24 U/ml (1 U = 1 mumol [3H]oleic acid released from tri[3H]olein/h). Lipolytic activity increased after lipid infusion to 4.04 +/- 0.96, 4.32 +/- 0.63, and 6.09 +/- 1.00 U/ml on days 1, 2, and 3 of the study. Hepatic lipase amounted to 38-47% of total lipolytic activity. During the 3 days of lipid infusion, there were dose-dependent increases in plasma FFA, triglyceride, and cholesterol. Whereas FFA and triglyceride concentrations returned to prelipid infusion levels 9 h after stopping the infusion of Intralipid, 1, 2, or 3 g/kg, there was a cumulative increase in plasma cholesterol and glucose concentrations. The close correlation between FFA concentrations and plasma lipolytic activity (r = 0.655, p less than 0.001) suggests considerable intravascular lipolysis. The positive correlation between plasma FFA and triglycerides (r = 0.632, p less than 0.001) and FFA and cholesterol (r = 0.582, p less than 0.001) indicate, however, that intravascular lipolysis does not prevent the lipemia associated with Intralipid infusion to low birth weight infants.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Total parenteral nutrition with intralipid in premature infants receiving TPN with heparin: effect on plasma lipolytic enzymes, lipids, and glucose. 312 35

Long chain n-3 fatty acids present in fish oils have been shown to reduce fasting plasma triglyceride and very low density lipoprotein levels in normal and hyperlipidemic human subjects. The present studies were designed to examine whether dietary n-3 fatty acids influence chylomicron formation and metabolism in healthy volunteers. In the first study seven subjects were fed either saturated fat, vegetable oil, or fish oil-based diets for 4 weeks each, and test meals containing 50 g of the background fat were administered after the second week of each diet. The postprandial rise in triglyceride levels was significantly lower following the fish oil test meal as compared to the saturated fat or vegetable oil test meals. In the second study, six subjects eating their usual home diets were given two fat tolerance tests. The first contained saturated fat and the second, given 1 week later, contained fish oil. There was no difference in the postprandial triglyceride response between the fish oil and the saturated fat meals. A third study was then conducted with eight volunteers in which saturated fat and fish oil test meals were administered during saturated fat and fish oil background diets in a crossover design. The presence of fish oil in the background diet reduced postprandial lipemia regardless of the type of fat in the test meal. Although there was no effect of the fish oil diet on the lipoprotein lipase and hepatic lipase activity of postheparin plasma measured in vitro, stimulation of in vivo lipolysis was not ruled out. Our results suggest that chronic (but not acute) intake of fish oil may inhibit the synthesis or secretion of chylomicrons from the gut. However, accelerated clearance due to decreased VLDL competition cannot be excluded.
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PMID:Reduction of postprandial triglyceridemia in humans by dietary n-3 fatty acids. 324 Nov 21

Patients treated with corticosteroids often have a dyslipoproteinemia characterized by elevated plasma levels of triglyceride and low density lipoprotein cholesterol and/or decreased levels of the high density lipoprotein2 fraction of high density lipoprotein cholesterol. This study was undertaken to determine if such patients also have elevated apolipoprotein-B (apoB) levels and/or abnormalities of the activities of the triglyceride lipases in postheparin plasma. Plasma lipoprotein levels and the postheparin activities of hepatic lipase and lipoprotein lipase were measured in 28 women with systemic lupus erythematosus (SLE) who were treated with prednisone, 10 women with SLE not treated with prednisone, and 15 normal women. The prednisone-treated group had higher mean plasma levels of triglyceride [2.06 +/- 1.3 (+/- SD) vs. 1.15 +/- 0.35 and 0.95 +/- 0.46 mmol/L; P less than 0.01], low density lipoprotein cholesterol [3.41 +/- 1.4 (+/- SD) vs. 2.79 +/- 0.67 and 2.84 +/- 0.70 mmol/L; P less than 0.01], and apoB [1.16 +/- 0.35 (+/- SD) vs. 0.82 +/- 0.13 and 0.76 +/- 0.22 g/L] than the other 2 groups. Forty-three percent of the prednisone-treated group had apoB levels of 1.20 g/L or more compared to 7% of normal subjects and none of the untreated SLE group (P less than 0.05). However, of the 12 prednisone-treated patients with elevated plasma apoB levels 5 had normal plasma lipid levels. There were no differences in the postheparin lipase activities among the 3 groups. These data indicate that corticosteroid-treated patients have elevations in apoB as well as hyperlipidemia. The lipoprotein abnormalities may explain the increased risk of atherosclerosis reported in these patients.
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PMID:Elevated apolipoprotein-B levels in corticosteroid-treated patients with systemic lupus erythematosus. 341 Sep 32

There is much evidence that altered lipid metabolism contributes to the development of coronary artery disease (CAD). It is generally accepted that there is a direct association between the extent of CAD and total plasma cholesterol, as well as an inverse association between the extent of CAD and plasma HDL-cholesterol. No general agreement exists about the atherogenetic potential of plasma triglycerides and of triglyceride-rich lipoproteins. Since lipoprotein lipase (LPL) is the key-enzyme in the catabolism of triglyceride-rich lipoproteins (chylomicrons and very low-density lipoproteins), we examine the relationship between triglyceride-rich lipoproteins and LPL in vitro and in vivo. The concentrations of the main lipoprotein density classes, namely very low-density lipoproteins (VLDL), intermediate-density lipoproteins (IDL), low-density lipoproteins (LDL), high-density lipoproteins2 (HDL2) and HDL3, are measured by rate zonal ultracentrifugation. The preparation of VLDL, IDL, LDL, HDL2, and HDL3 is performed by sequential ultracentrifugation. The activity of LPL is measured radioenzymatically in a glycerol-based triolein emulsion. It can be demonstrated in vitro that VLDL, IDL, and HDL2 from normal plasma are able to increase LPL-activity in contrast to VLDL, IDL, and HDL2 from hyperlipemic plasma. This difference seems to be caused by an altered composition of apolipoproteins in hyperlipemic lipoproteins. An artificial acidosis in three healthy subjects shows in contrast to alkalotic and neutral blood-pH a significant decrease of LPL-activity. This result seems to be of some interest, since diseases associated with acidotic blood-pH, such as chronic renal disease, diabetes mellitus or chronic alcoholism, show secondary hyperlipemias caused by a deficit of LPL-activity. It can be shown in 15 male patients who produce a secondary type-V hyperlipemia during severe abuse of alcohol, that LPL-activity is decreased significantly as compared to 15 healthy controls. During sober phases, this alcohol-induced hyperlipemia and the impairment of LPL-activity disappears completely. In an other group of 8 male patients, who are not producing severe secondary hyperlipemia during approximately the identical alcohol intake, LPL-activity is also significantly decreased, but the activity of hepatic lipase is significantly increased. This increase of the activity of hepatic lipase seems to protect these patients from the development of secondary type-V hyperlipemia. In 89 male patients with angiographically assessed CAD a very strong inverse association between the activity of LPL and the extent of CAD is found.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:[Pathologic decrease in lipoprotein lipase activity in relation to the development of hyperlipemias and their significance for coronary heart disease]. 345 43

The authors review the present status of our knowledge of the physiopathology of primary hyperlipidaemia. The mechanisms of familial hypercholesterolaemia (reduction in the number of LDL receptors on the surface of hepatic and extrahepatic cells) and of type III hyperlipidaemia (an apo E abnormality associated with another metabolic disorder) are relatively well known. However, the physiopathology of the other hyperlipidaemias remains obscure: polygenic hypercholesterolaemia probably due to a disorder of hepatic LDL receptors; combined familial hyperlipidaemia probably due to abnormally high hepatic apo B synthesis; hyperlipidaemia related to defective chylomicron catabolism in which the lipase system plays a central role and hypertriglyceridaemia caused by an association of genetic and environmental factors.
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PMID:[Physiopathology of primary hyperlipidemias]. 352 30

Lipoprotein lipase (LPL) activity in postheparin plasma of 38 normolipidemic volunteers was related to the magnitude of postprandial lipemia after a fat meal, to triglyceride content of high density lipoprotein2 (HDL2), to hepatic lipase (HL) activity, and to HDL2 levels. LPL activity correlated indirectly with lipemia, triglyceride content of HDL2, HL activity, and levels of HDL2 but not of HDL3. HL activity correlated directly with lipemia and indirectly with HDL2 levels. Triglyceride content of HDL2 correlated directly with lipemia and indirectly with HDL2 levels. In HDL2, abundance of apolipoprotein (apo) A-II and the apoA-I/apoA-II ratio varied widely. The latter correlated positively with LPL activity and HDL2 levels, and, inversely, with HL activity, lipemia, and triglyceride content of HDL2. The study suggests that HDL-cholesterol is not an independent parameter of lipid transport, but is strongly affected by triglyceride metabolism through lipolytic enzymes, as exemplified by postprandial lipemia that affect both composition and plasma levels of HDL2.
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PMID:High density lipoprotein2. Relationship of the plasma levels of this lipoprotein species to its composition, to the magnitude of postprandial lipemia, and to the activities of lipoprotein lipase and hepatic lipase. 361 51

The optical aberrations due to the presence of the turbidity caused by hyperlipidemia has been eliminated in two serum glucose procedures. This has been accomplished by incorporating lipase and alpha-cyclodextrin into the two glucose reagents. The hydrolytic action of the lipase generates water soluble glycerol and insoluble fatty acids. By including the chemical scavenger alpha-cyclodextrin into the reagent the fatty acids are solubilized and thus the production of a second turbidity is avoided. Because the clearing reagents are incorporated into the glucose reagents, this is an on-line process and no additional labor is required to clear the sample-reagent mixture. Furthermore, no additional time is required as the clearing occurs in the same period of time that it takes for the indicator reactions to reach equilibrium.
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PMID:On-line clarification for the measurement of serum glucose in hyperlipidemic specimens. 370 61

The main lipoprotein density classes, namely very-low-density lipoproteins (VLDL), intermediate-density lipoproteins (IDL), low-density lipoproteins (LDL), high-density lipoproteins2 (HDL2) and HDL3 were investigated with respect to their influence on hepatic lipase (HTGL) activity in vitro. Lipoproteins from pooled normal plasma (NP) and from pooled hyperlipemic plasma (HP) were prepared by means of sequential ultracentrifugation. Hepatic lipase was determined radioenzymatically after preincubation with protamine sulfate. It could be demonstrated that IDL from HP were able to stimulate HTGL activity by approximately 100% above the baseline value. HDL3 from both NP and HP revealed an inhibiting effect on HTGL activity. VLDL, LDL, and HDL2 exhibited no significant effect on HTGL activity. It is speculated that HTGL could possibly represent a second pathophysiological pathway for the catabolism of IDL in hyperlipemia but this presumption is supported by only a few investigations in vivo.
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PMID:Stimulating effect of intermediate-density lipoproteins (IDL) from hyperlipemic plasma on hepatic lipase. 372

Several parameters of lipoprotein metabolism were examined in 38 men with primary hypertriglyceridemia (phenotype IV). Family investigation showed that 17 men had familial combined hyperlipidemia (FCH), seven had familial hypertriglyceridemia (FHT), and 14 had unclassified hypertriglyceridemia (UNC). In all three groups, plasma high density lipoprotein (HDL) cholesterol and the concentrations of apolipoprotein A-I and A-II were decreased, and apolipoprotein B was increased, each to the same extent. These results are compatible with an increased risk of cardiovascular disease in both FCH and FHT patients. The mean concentration of LDL cholesterol and the ratio of LDL to HDL cholesterol were significantly higher in FCH subjects, which could explain their increased risk. Postheparin lipoprotein lipase and hepatic lipase were the same in both groups. Determination of apolipoprotein C composition, which may modulate lipoprotein lipase activity, did not reveal any abnormalities in the different groups. In both FCH and FHT, the mean turnover rate of plasma triglycerides was almost twice normal, indicating that overproduction of plasma triglyceride plays an important role in both disorders. However, there was an overlap with normal controls, indicating impaired triglyceride removal in some subjects. The underlying mechanism of hypertriglyceridemia in FCH and FHT therefore seems to be heterogeneous.
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PMID:Plasma lipoproteins, apolipoproteins, and triglyceride metabolism in familial hypertriglyceridemia. 372 96


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