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

Five analbuminemic inbred strains of rats (AD/1, AD/2, AD/3, AD/4, AD/5) were established from Nagase analbuminemic rats (NAR). They showed no genetic differences in coat color, biochemical marker gene loci and skin grafting test. Their serum levels of total cholesterol, phospholipids, triglycerides, and beta-lipoproteins were compared with normal inbred strains (L) derived from Sprague-Dawley rats. Their plasma apoproteins were also examined. All inbred strains of analbuminemic rats showed hyperlipidemia progressing with age although there were slight variations in their lipid and apoprotein levels. These analbuminemic inbred strains of rats may be multigenic models of lipid metabolism abnormality.
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PMID:Establishment and characteristics of five analbuminemic inbred strains of rats. 332 99

There is general agreement as to the effects of diabetes on the concentrations of certain plasma lipoprotein lipids. Subdivision of diabetic subjects into several clearly defined subgroups has revealed that the detailed patterns of lipoprotein and lipid changes are dependent upon several factors, perhaps the most important of which is the degree of glycaemic control. Several aspects remain controversial, the most outstanding being whether or not plasma LDL cholesterol levels are elevated. It is possible that this is the case in certain clearly defined subgroups but not in others. In assembling the results of recent research for this review, two important aspects have emerged which require clarification. The first is the question of whether or not insulin directly stimulates hepatic VLDL secretion. The possibility that insulin might regulate production of lipogenic substrate by the gut may have an important bearing on this problem. The exact means by which insulin co-ordinates the metabolic activities of these organs in such a way as to ensure plasma lipid balance is not yet known and further research in this area may help to resolve some outstanding problems associated with diabetic hyperlipidaemia. Second, changes in the relative lipid composition of certain lipoprotein fractions in diabetic subjects has provided indirect evidence that increased lipoprotein 'remnant' concentrations may contribute to the abnormalities observed in some groups of diabetic subjects. This interesting possibility has been supported by metabolic studies, mainly in experimental animals. If this proves to be correct, then it remains to be determined whether the remnants involved are of hepatic or intestinal origin and whether the metabolic defect is related to abnormal production, clearance, or both. Recent work on the effects of changes in the apoprotein and lipid content on the metabolism of other lipoproteins in diabetes may have a useful bearing on studies of this type. In this respect, the bulk of the evidence seems to suggest that these factors, rather than changes in lipoprotein receptor activity per se, are important in determining the clearance of atherogenic lipoproteins such as LDL in diabetes.
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PMID:Hyperlipidaemia of diabetes. 353 93

A 61-year-old woman was treated with tamoxifen for breast cancer and had marked hyperlipoproteinemia: high plasma triglyceride levels (2790 mg/dl); increased very low density lipoprotein (VLDL) cholesterol levels (241 mg/dl); and high VLDL apoprotein B levels (126 mg/dl). Low density lipoprotein (LDL) cholesterol was decreased (104 mg/dl) and LDL apoprotein B was at 107 mg/dl. A low activity of both postheparin plasma lipoprotein lipase (LPL) and hepatic triglyceride lipase (h-TGL) was also noted. All these observations were reversed following tamoxifen withdrawal. Plasma triglyceride levels fell to 361 mg/dl. VLDL cholesterol and VLDL apoprotein B decreased to 41 mg/dl (83%) and 21 mg/dl (83%), respectively. Meanwhile, LDL cholesterol rose to 194 mg/dl (86%) and LDL apoprotein B increased to 138 mg/dl (29%). LPL and h-TGL activities did increase following tamoxifen withdrawal. Our observations show that, in some patients, the previously described weak hypertriglyceridemic effect of tamoxifen is amplified. That observation supports the concept and helps to explain that, in such severe induced lipemia, reduction of the activities of LPL and h-TGL might impede the conversion of VLDL to LDL, thus causing an amplification of the effect.
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PMID:Severe lipemia induced by tamoxifen. 369 11

The effect of diets containing soybean proteins substituting a significant portion of meat proteins was studied in patients with hyperlipidemia, type IIa, and in experiments on rats. It was found that soybean proteins included into the diet induced blood plasma amino acid imbalance, changed the excretion of some amino acids with urine, and significantly diminished the blood plasma cholesterol level. In the experiments on rats a reduced rate was noted in the low-density lipoprotein apoprotein formation and high-density lipoprotein apoprotein regeneration in the blood plasma. It is suggested that the hypocholesterolemic effect of soybean proteins is caused by decreased apoprotein E synthesis and metabolism due to low levels of blood plasma lysine and arginine.
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PMID:[Clinico-experimental approaches to studying the hypocholesteremic action of soy proteins]. 370 42

Lipoprotein lipase and hepatic lipase activities are very low in tissues of mice born with genetic combined lipase deficiency (cld/cld). Consequently, if allowed to suckle, the mice develop severe hyperlipemia and die within 3 days. The ultrastructure of capillaries and parenchymal cells in tissues that normally contain lipoprotein lipase and hepatic lipase was studied in tissues from cld/cld and unaffected mice 6 to 24 hours of age. Capillaries in tissues from suckled cld/cld mice were packed with numerous abnormally shaped chylomicrons. There was close contact between surfaces of chylomicrons and the luminal plasma membrane of endothelium. Chylomicrons were sometimes found between endothelial cells and in the subendothelial space in heart, lung, and liver, and in the lumen of lung alveoli. In contrast, capillaries of suckled unaffected mice contained very few chylomicrons, and the subendothelial spaces and lung alveoli were free of chylomicrons. Myocytes of diaphragm and heart from suckled cld/cld mice did not contain lipid droplets, whereas brown adipocytes contained a few small droplets. Parenchymal cells in diaphragm, heart, brown adipose tissue, and lung from suckled unaffected mice contained numerous large lipid droplets. Hepatocytes of suckled cld/cld mice contained small irregularly shaped lipoprotein particles (100 A) in endoplasmic reticulum and Golgi, numerous large lysosomes containing small lipoprotein particles, lipid spheres and lamellar structures, and no intracellular lipid droplets, whereas hepatocytes of suckled unaffected mice contained larger lipoprotein particles (400 A), large lipid droplets, and very few lysosomes. Triacylglycerol of chylomicrons from cld/cld mice was readily hydrolyzed by bovine lipoprotein lipase in vitro, and this effect was not augmented by heat-inactivated serum, indicating that the chylomicrons contained adequate amounts of apoprotein C-II. Thus, the large amount of chylomicrons in capillaries and small amount of lipid droplets in cells of suckled cld/cld mice reflect the very low level of lipoprotein lipase activity in these animals. The findings in hepatocytes indicate that lipoprotein metabolism in liver is markedly disturbed in cld/cld mice.
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PMID:Effect of the combined lipase deficiency mutation (cld/cld) on ultrastructure of tissues in mice. Diaphragm, heart, brown adipose tissue, lung, and liver. 374 49

Lipoprotein composition varies among different genetic forms of hyperlipidemia. An increase in hepatic triglyceride (TG) synthesis in subjects with familial hypertriglyceridemia (FHTG) is associated with secretion of large, TG-enriched, very low-density lipoproteins (VLDL), which have an increased affinity for lipoprotein lipase (LPL) in vivo as compared with VLDL from subjects with familial combined hyperlipidemia (FCHL) or from normal subjects. Elevated levels of plasma low-density lipoprotein (LDL) apoprotein B in FCHL are associated with high apoprotein B production rates. The LDL in FCHL is heterogeneous, with a preponderance of an LDL subfraction, which is denser, smaller, and lipid poor as compared with LDL from normal subjects. The more buoyant LDL subfraction in FCHL seems to be catabolized more rapidly than this dense LDL subfraction.
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PMID:Metabolic consequences of genetic heterogeneity of lipoprotein composition (lipoprotein heterogeneity). 381 12

Alterations in plasma lipoprotein lipid and apoprotein accompanying the hyperlipidemia of rats bearing Morris hepatoma 7288C were characterized. In tumor-bearing animals all plasma lipid classes except cholesterol ester (CE) were elevated, particularly free cholesterol (FC) and triglyceride (TG), which increased by 57 and 63%, respectively. Fasting only partially reduced the tumor-induced hyperlipidemia and had no effect on the ratios of FC/CE and TG/CE. Analysis of plasma lipoproteins revealed an elevation of VLDL, IDL, and LDL in host rats, with more than a 2-fold increase in both lipid and protein of VLDL. In contrast, the three high density fractions, HDL2, HDL3, and d greater than 1.21 g/ml, were reduced. The inverse changes in concentration of host lipoproteins of lower versus higher density indicate a defective catabolism of TG-rich lipoprotein. This possibility is supported by the analysis of apolipoprotein. The percentage of total apoprotein contributed by apo C-I and C-II was reduced in all host fractions except HDL2, while the C-IIIs remained unchanged except for a small decrease in C-III-3 of host VLDL and a slight increase in the combined C-IIIs of HDL2. These changes were reflected in the decreased C-I+C-II/C-III ratios of all host lipoprotein fractions. Apo E levels remained similar to control values except for a significant decrease in HDL2. Host VLDL showed increased apo A-IV and A-I content, while A-IV was decreased in HDL2. Changes in apo B profiles were also observed.
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PMID:Characterization of alterations in plasma lipoprotein lipid and apoprotein profiles accompanying hepatoma-induced hyperlipidemia in rats. 394 72

In a double blind study 27 patients with type II hyperlipidemia (8 IIa and 19 IIb) were treated as follows: 13 received placebo and 14 sn-polyenylphosphatidylcholin (PPC) (P 0206/1/01, Nattermann GmbH, Cologne) in a dose of three times 450 mg b.i.d. In all patients, and also in the two subclasses of patients with type IIa and type IIb hyperlipidemia, total cholesterol and LDL cholesterol were lowered significantly by PPC. The other parameters showed only minor variation. There was a downward trend in apoprotein B, triglycerides and VLDL cholesterol, and an upward trend in apoprotein AI, with virtually unchanged HDL cholesterol. None of these variations was significant compared with placebo. The fall in LDL cholesterol with unchanged HDL cholesterol caused a statistically significant decrease in the LDL cholesterol/HDL cholesterol ratio, thus supporting the hypothesis of an antiatherogenic property of PPC, as demonstrated experimentally in various animals.
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PMID:[Modification of serum lipids, lipoproteins and apoproteins AI and B in patients with hyperlipidemia Type IIa and IIb using polyenylphosphatidylcholine]. 403 28

Nine (amino-methyl)-2 acrylophenone derivatives having in vitro antimicrotubular activities very similar to those of colchicine are tested on Triton WR 1339-induced hyperlipidemia in rats. By producing a disorganization of the microtubular system, these drugs reduce the lipoprotein secretory process from hepatocytes, and more particularly the triglyceride-rich VLDL secretory process, such that the serum triglyceride, cholesterol and phospholipid levels are decreased. On the other hand, HDL-cholesterol and HDL-phospholipids are increased in a significant manner. Other studies show that serum apoprotein B levels are decreased while serum apoprotein A1 levels are increased. These results are interesting since atherogenous risk is now known to be dyslipemia-related, and is not the same according to the fact that lipids are bound to one or another lipoprotein. Among the four most effective compounds (5,7,8 and 9) three of them possess a methoxy group on the aromatic ring, which seems to distinguish that series from the other two.
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PMID:Pharmacological study of nine antimicrotubular drugs with acrylophenone structure on Triton WR 1339-induced hyperlipidemia in rats. 408 77

Apolipoproteins of the "C" group in human blood plasma, which contain the activator of the lipoprotein lipase-substrate interaction, were found to be transferred specifically from serum to phospholipid-stabilized fat emulsion. Content and distribution of apoprotein activator were measured in healthy men in the postabsorptive state and 4 h after ingestion of meals containing 100 g fat. Content of activator protein in whole serum did not change after ingestion of the fat-rich meals but that contained in triglyceride-rich lipoproteins of density (d) <1.006 approximately doubled whereas that of high density lipoproteins fell by half. The increased activator content of triglyceride-rich lipoproteins was virtually confined to chylomicrons and its concentration in chylomicron apoprotein was substantially greater than that in very low density lipoproteins. This difference could be ascribed largely to a higher content of C apoproteins in chylomicron protein since both the concentration of C apoproteins and of apoprotein activator were directly proportional to particle diameter while the pattern of fast-migrating C apoproteins in polyacrylamide gels was similar among chylomicrons and subfractions of very low density lipoproteins. Apparent concentration of activator protein was much greater in the high density lipoprotein subfraction of d 1.063-1.125 than in the subfraction of d 1.125-1.21. In the subfraction of d 1.063-1.125, the concentration of activator protein and of fast-migrating C apoproteins in polyacrylamide gels decreased after the fat-rich meal. Concentration of phospholipids in this fraction increased gradually to a peak 43% above the basal value 6 h after the meal. The results obtained demonstrate that high density lipoproteins contribute certain functionally important polar constituents to chylomicrons during alimentary lipemia in man and suggest that they also receive surface constituents from chylomicrons during the course of their metabolism.
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PMID:Interchange of apolipoproteins between chylomicrons and high density lipoproteins during alimentary lipemia in man. 434 2


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