UMLS:C0432222 - FACTA Search

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Query: UMLS:C0432222 (SEM)
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Post-heparin plasma lipoprotein lipase activity was measured in 28 cancer patients with varying degrees of weight loss, and in 16 normal volunteers. Total lipoprotein lipase activity was decreased by 35.4% (P less than 0.001) in the cancer group. The component lipase activities, hepatic (HLPL), and peripheral (PLPL), were decreased by 40% (P less than 0.001) and 38% (P less than 0.005) respectively. In addition, the level of total peripheral lipoprotein lipase correlated well with the percent body weight lost by these patients (r = 0.6, P less than 0.01). Regardless of extent of disease, patients with lung cancer showed the lowest enzyme activity (mean 191 mU/ml +/- 30 SEM, P less than 0.001) and the greatest percent of weight loss (mean 16%), while patients with breast cancer had nearly normal lipase activity (mean 315 mU/ml +/- 50 SEM, normal 340 mU/ml +/- 22 SEM, P less than 0.10) and minimal weight loss (mean 8.4%). Fasting serum triglycerides were significantly elevated in the patient group (mean 120 mg/dl +/- 9.7 SEM) as compared to normal (mean 71 mg/dl +/- 7 SEM, P less than 0.001). The mean fasting insulin level was elevated in the patient group (13 mU/ml +/- 3.0 SEM), although in the majority of the patients it was found within the normal range (4-24 mU/ml). We conclude that the significant decrease in the total LPL activity may be responsible in part for the characteristic hypertriglyceridemia present in cancer patients.
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PMID:Reduced plasma lipoprotein lipase activity in patients with malignancy-associated weight loss. 378 75

Normal rats fed an isocaloric sucrose-rich diet (SRD) for 3 weeks developed high levels of triacylglycerol in plasma (P) (mmol triacylglycerol I-1) heart (H) and liver (L) tissues (mumol triacylglycerol mg DNA-1) as compared to control rats fed the standard chow (STD) (X +/- SEM; P: SRD 1.32 +/- 0.06 vs STD 0.49 +/- 0.05, P less than 0.001; H: SRD 2.1 +/- 0.17 vs STD 0.94 +/- 0.01, P less than 0.001; L: SRD 8.48 +/- 1.47 vs STD 1.71 +/- 0.12, P less than 0.001). A simultaneous drop in the activities (mumol glycerol ml-1 hr-1) of several plasma post heparin lipolytic enzymes was observed; total triglyceride lipase (T-TGL): SRD 5.32 +/- 0.34 vs STD 7.48 +/- 0.64, P less than 0.01; lipoprotein lipase (LPL): SRD 1.61 +/- 0.26 vs STD 2.42 +/- 0.41, P less than 0.05; hepatictriglyceride lipase (H-TGL): SRD 3.71 +/- 0.28 vs STD 5.05 +/- 0.69, P less than 0.05 and monoglyceride hydrolase (MGH) (mumol glycerol I-1 min-1): SRD 558 +/- 108 vs STD 1165 +/- 45, P less than 0.001. Rats fed the SRD presented glucose intolerance after i.v. glucose (Kg X 10(-2); 1.06 +/- 0.09 vs 2.61 +/- 0.14 of STD, P less than 0.001) in spite of the presence of hyperinsulinism (sigma plasma IRI microU/ml from 0 to 30 min: 184.6 +/- 23.6 vs 100.5 +/- 9.7 of STD, P less than 0.01) suggesting that a state of insulin resistance had developed.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of tiadenol and clofibrate on plasma post heparin lipolytic hepatic, extrahepatic and monoglyceride hydrolase activities in rats with hypertriglyceridemia induced by a sucrose rich diet. 400 66

The cellular regulation of adipose tissue lipoprotein lipase by insulin was investigated using cultured isolated rat adipocytes. Evidence for sustained cell viability over 3 days included stability of specific [125I]insulin binding and adipocyte number. Lipoprotein lipase was measured in three functional compartments: 1) enzyme activity secreted into the culture medium, 2) activity releasable from cell suspensions by heparin, and 3) activity extractable from cells (after maximal heparin release) in deoxycholate and detergent. One day after preparation, these activities stabilized and were 1.3 +/- 0.2, 1.4 +/- 0.2, and 7.7 +/- 0.9 neq/10(6) cells X min, respectively (n = 24, mean +/- SEM). Insulin, added the day after preparation, produced a dose-dependent (1-400 ng/ml) increase in lipoprotein lipase releasable from cells by heparin at 2, 4, and 24 h. Insulin also increased intracellular enzyme measured as deoxycholate-detergent-solubilized activity extracted from previously heparin-released cells. However, insulin-mediated increases in culture medium enzyme only occurred subsequent to cellular effects. All insulin-mediated effects were prevented by cycloheximide (1 microgram/ml). Thus, insulin increased two cellular pools of adipocyte lipoprotein lipase in a dose-dependent manner, but had no direct effect on enzyme secretion. Overall, cultured isolated rat adipocytes appear to be a valuable system for the study of lipoprotein lipase regulation at the level of the adipocyte.
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PMID:Insulin regulation of lipoprotein lipase in cultured isolated rat adipocytes. 637 Jun 64

Because increases in adipose tissue lipoprotein lipase (ATLPL) may be important in the pathogenesis of obesity, the response of ATLPL to insulin during maintenance of euglycemia was examined in 22 obese and 8 normal weight subjects. Basal levels of ATLPL per g fat tissue for the obese and control groups were 18.7 +/- 2.0 (+/- SEM) and 9.6 +/- 2.7 neq/g X min, respectively. Insulin and glucose infusion rapidly produced antilipolysis in both groups, as evidenced by large falls in FFA by 20 min. When the responses of ATLPL in absolute change from basal were compared between the obese and control groups, no significant differences were found. However, because of the higher baseline ATLPL values in the obese subjects, the percent change in ATLPL from basal was significantly blunted at the 80 (P = 0.02), 180 (P less than 0.05), and 360 (P = 0.005) min timepoints compared to those in the normal subjects. By 3 h into the infusion, the control group had a significant rise in ATLPL above the basal level (4.2 +/- 1.3 ngq/g X min; P = 0.01), whereas the obese group did not (2.3 +/- 1.9 neq/g X min; P = NS). However, by 6 h, the ATLPL per g response above baseline was significantly increased in both normal (19.2 +/- 6.5 neq/g X min; P = 0.01) and obese subjects (9.8 +/- 2.3; P less than 0.001). Because adipose cell size was greater in obese subjects, data were also expressed per 10(6) cells. Basal ATLPL per 10(6) cells [11.8 +/- 1.7 neq/10(6) cells X min (obese); 3.4 +/- 0.9 neq/10(6) cells X min (normal)] was a function of cell size (rs = 0.713; P less than 0.001), body mass index (rs = 0.565; P less than 0.005), and basal insulin levels (rs = 0.434; P less than 0.05). As with the ATLPL per g response, the increases in ATLPL per 10(6) cells above basal were significant at both the 3 and 6 h marks for the normal subjects, but only at the 6 h timepoint for the obese group. Both steady state insulin levels [342 +/- 24 microU/ml (obese); 251 +/- 27 microU/ml (normal)] and the glucose infusion rates needed to maintain euglycemia [319 +/- 23 mg/m2 X min (obese); 312 +/- 33 mg/m2 X min (normal)] did not correlate with changes in ATLPL. Thus, insulin responsiveness of ATLPL in obese subjects was delayed but preserved. This phenomenon may be important in maintenance of the obese state.
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PMID:Insulin responsiveness of adipose tissue lipoprotein lipase is delayed but preserved in obesity. 638 39

The acute effect of fat feeding on the insulin-mediated stimulatory response of adipose tissue lipoprotein lipase (ATLPL) was examined in normal-weight subjects. After two days of isocaloric-formula feeding, subjects were divided into the following four groups: intravenous (IV) saline alone (sal) (n = 5), IV saline and 67 g of oral corn oil ingested at the outset of the infusion (sal/fat) (n = 5), IV insulin (40 mU/m2/min) and glucose to maintain euglycemia (ins/glu) (n = 9), and IV insulin and glucose and oral corn oil (ins/glu/fat) (n = 8). Triglycerides fell less in the ins/glu/fat group than in the ins/glu group (0 +/- 8% v 35 +/- 5%, means +/- SEM, at three hours, P less than 0.01; 15 +/- 8% v 43 +/- 6% at six hours, P less than 0.02). ATLPL in the sal and sal/fat groups did not change during the six-hour period. When the responsiveness of ATLPL was compared between ins/glu/fat subjects and ins/glu subjects, decreases were seen at both three and six hours (-0.3 +/- 3.0 v 15.1 +/- 5.4 nEq/g/min, P less than 0.05; 6.7 +/- 2.7 v 27.9 +/- 3.9 nEq/g/min, P less than 0.001). The glucose infusion rates needed to maintain euglycemia were also decreased by fat feeding, 229 +/- 18 v 287 +/- 20 mg/m2/min (P less than 0.05). Thus, fat feeding with insulin and glucose infusions diminishes the insulin responsiveness of ATLPL.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Fat feeding decreases insulin responsiveness of adipose tissue lipoprotein lipase. 638 65

We have previously reported that normal Wistar rats fed an isocaloric, sucrose-rich (63%) diet (SRD) developed glucose intolerance and elevated triglyceride levels in plasma as well as in heart and liver tissue. This metabolic state was accompanied by hyperinsulinism both in vivo and in vitro, suggesting that a state of insulin resistance has developed. The aim of this study was to gather information on the various plasma post-heparin lipolytic activities in rats fed a SRD. Hepatic triglyceride lipase (H-TGL) was evaluated by both, protamine sulfate inhibition (PSI) of extrahepatic lipoprotein lipase (LPL) and heparin-Sepharose affinity chromatography (H-SAC). Both methods rendered comparable results. Total triglyceride lipase (T-TGL) was measured after Krauss et al. and monoglyceride hydrolase (MGH) after Vogel et al. Our results have shown a significant decline of plasma T-TGL (5.32 +/- 0.34 means +/- SEM vs. 7.48 +/- 0.64 mumol glycerol ml-1 h-1; p less than 0.01), H-TGL (3.71 +/- 0.28 vs. 5.05 +/- 0.69; p less than 0.05), LPL (1.61 +/- 0.26 vs. 2.42 +/- 0.41; p less than 0.05) and MGH (558 +/- 108 mumol glycerol l-1 min-1 vs. 1,165 +/- 45; p less than 0.001) activities. Thus, feeding a sucrose-rich diet induced a state of hyperlipemia and insulin resistance in which not only plasma T-TGL but also H-TGL and MGH activities were significantly decreased. This suggests that the latter two enzymes are also under nutritional and/or hormonal control.
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PMID:Post-heparin plasma hepatic triglyceride lipase and monoglyceride hydrolase activities in hyperlipemia induced by a sucrose rich diet. 661 28

Human and guinea-pig placental activity was measured in tissue extracts and in medium in which tissue fragments have been incubated. Lipase activity was estimated from measured rates of release of 3H-labelled fatty acids from a 3H-labelled triacylglycerol substrate. Whole tissue lipase activity was 1.6 +/- 0.3 units/g (mean +/- SEM, mumol of unesterified fatty acid release/min) in the human, and 87.1 +/- 7.3 units/g in guinea-pig placental tissue. 70% of the human and 56% of the guinea-pig placental activity was lost on treating the tissues with cold acetone. Sodium chloride (0.75 M) decreased activity by 50% in extracts from both species. Lipase activity was released into media when placental fragments were incubated. The addition of heparin increased the release of lipase from human placenta but not significantly from that of the guniea-pig. Insulin had no effect on placental lipase activity from either species. It is concluded that the placentas of both species contain at least two lipases. One of these, which constituted a large of the total, had the characteristics of lipoprotein lipase.
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PMID:Lipoprotein lipase activity in human and guinea-pig placenta. 714 75

Total parenteral nutrition (TPN) is now widely available, but there is a relatively little data relating to the optimal substrate support in different types of patients. In critically ill patients who require parenteral nutrition, underlying metabolic alterations will influence the capacity for substrate utilization; in them, fat emulsion may serve as a useful energy source but may also have deleterious effects. The intravenous fat tolerance test has been widely used as a measure of the capacity of the organism to clear exogenous fat from the bloodstream. We have devised and employed a three-stage lipid clearance test using Intralipid-10% as a substrate. The rates of infusion are such that first order kinetics are followed during the first two stages yielding fractional removal rates, and zero order kinetics are followed during the third infusion yielding maximal clearance rates. Six injured and 6 infected patients displayed a greater capacity for lipid clearance than 13 normal subjects. Four injured patients who also had received multiple transfusions failed to show this response. Fractional removal rates were influenced by injury and infection to a greater extent than maximal clearance rates. Models are presented utilizing enzyme saturation kinetics and treating endogenous triglyceride as a competitive inhibitor (for the enzyme-substrate system of lipoprotein lipase-Intralipid triglyceride). The importance of employing enzyme saturation kinetics in the interpretation of lipid clearance tests is noted. The calculated apparent Michaelis-Menten constant for Intralipid triglyceride during the lipid clearance test is 521 +/- 38 (SEM) micromole/liter. In vitro systems utilizing Intralipid triglyceride as a substrate have yielded values in this range.
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PMID:Plasma clearance of fat emulsion in trauma and sepsis: use of a three-stage lipid clearance test. 719 17

A specific, accurate, and sensitive double antibody radioimmunoassay for measuring human apolipoprotein (apo) C-III has been developed. Anti-apoC-III(1) developed in rabbits cross-reacted completely with apoC-III subspecies. Analytical isoelectric focusing of delipidated triglyceride-rich lipoproteins (TRL) was done to assess the percentage of total apoC-III mass comprised by apoC-III(0), C-III(1), and C-III(2), and the data were used to compute the absolute plasma TRL apoC-III subspecie concentration. Total plasma apoC-III was 11.1 +/- 0.9 mg/dl (mean +/- SEM) in 29 normolipidemic healthy subjects; 21.3 +/- 4.9, 27.5 +/- 2.2, and 53.6 +/- 7 mg/dl in 3, 16, and 13 patients with primary types III, IV, and V hyperlipoproteinemia, respectively, and significantly (P < 0.01) higher than normal. Total plasma triglycerides (TG) correlated positively with total plasma apoC-III (r = 0.88; P = 0.0001) and TRL apoc-III (r = 0.88; P = 0.0001). Progressive hypertriglyceridemia was associated with a rise in the percent of total apoC-III in TRL isolated at d < 1.006 g/ml (r = 0.78; P < 0.0001; n = 43) and a reciprocal decline in the TRL-free plasma fraction (d > 1.006 g/ml). ApoC-III comprised significantly more of HDL(2) than HDL(3) protein (7.3 +/- 0.2 versus 1.6 +/- 0.2%, respectively, P < 0.01). HDL(2) and HDL(3) isolated from patients with type IV hyperlipoproteinemia had subnormal apoC-III as percent of total protein (2.4 +/- 0.5 and 0.6 +/- 0.1, respectively). Total plasma TG correlated negatively with i) apoC-III as percent of total HDL protein (r = -0.67; P = 0.002, n = 20); ii) apoC-III as percent of total HDL(2) protein (r = -0.52; P = 0.019); and iii) apoC-III as percent of total HDL(3) protein (r = -0.72; P = 0.0004). Plasma TRL apoC-III subspecie concentrations were significantly higher in the three hypertriglyceridemic groups (primary types III, IV, and V) compared to normals. TRL apoC-III(0) levels in patients with type IV and V were comparable (2.4 +/- 0.3 and 2.2 +/- 0.6 mg/dl, respectively). However, TRL apoC-III(1) and C-III(2) in patients with type V hyperlipoproteinemia were significantly higher (P < 0.01) than in patients with types IV or III hyperlipoproteinemia. Total plasma TG correlated positively with TRL apoC-III(0) (r = 0.56; P = 0.0004), TRL apoC-III(1) (r = 0.82; P = 0.0001) and TRL apoC-III(2) (r = 0.76; P = 0.0001). The slope of regression line relating total plasma TG with TRL apoC-III(1) was significantly steeper (P < 0.0001) than that for apoC-III(0). Thus, for a given interval of plasma TG, the change in concentration of TRL apoC-III(1) was much greater than that in TRL apoC-III(0). The development of the RIA and its combined use with analytical isoelectric focusing thus allows quantitation of this important glycopeptide and its subspecies in human plasma and its subfractions. Because apoC-III inhibits not only tissue lipoprotein lipase but also the hepatic uptake of triglyceride-rich lipoproteins and remnants, the data support the possibility that an abnormal metabolism of apoC-III subspecies may be linked pathogenetically to elevated plasma TG levels.-Kashyap, M. L., L. S. Srivastava, B. A. Hynd, P. S. Gartside, and G. Perisutti. Quantitation of human apolipoprotein C-III and its subspecies by radioimmunoassay and analytical isoelectric focusing: abnormal plasma triglyceride-rich lipoprotein apolipoprotein C-III subspecie concentrations in hypertriglyceridemia.
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PMID:Quantitation of human apolipoprotein C-III and its subspecie by radioimmunoassay and analytical isoelectric focusing: abnormal plasma triglyceride-rich lipoprotein apolipoprotein C-III subspecie concentrations in hypertriglyceridemia. 728 86

Post-heparin lipoprotein lipase (PH-LPL)-high density lipoprotein cholesterol (HDL-C) interrrelationships were assessed in 9 subjects with documented familial hyperalphalipoproteinemia (FHA) and in 8 controls to focus on potential biochemical etiologies of FHA and relationships of HDL-C to triglyceride hydrolysis and PH-LPL. FHA subjects had mean HDL-C and HDL2-C levels > twice controls; their PH-LPL levels (mean +/- SEM) (3.14 +/- 2.3 mumol FFA/h/ml) were also > twice that of controls (15.0 +/- 1.6) (P < 0.01), but post-heparin hepatic lipase levels (PH-HL) in the FHA and control subjects did not differ (18.1 +/- 1.6 vs 26.6 +/- 4.3, P > 0.1). For all subjects (FHA and controls) PH-LPL was positively correlated with HDL-C (r = 0.79, P < 0.01) and with HDL2-C (r = 0.90, P < 0.01), but not with HDL3-C (r = --0.02). There were no significant PH-HL and HDL-C interrelationships, P > 0.1. The amount of apo CII (the primary activator of PH-LPL) in HDL2 was greater in the FHA (mean +/- SEM) (16.1 +/- 2.5 microgram/ml plasma) than in control subjects (4.7 +/- 0.9, P < 0.01). There were strong positive correlations between HDL2 apo CII and both PH-LPL (r = 0.79, P < 0.01) and HDL2-C (r = 0.80, P < 0.01). Apo CII as a percentage of HDL2 protein was higher in FHA than control subjects (mean +/- SEM) (1.2 +/- 0.3% vs 0.5 +/- 0.2%, P < 0.01). Apo CII as a percentage of HDL3 protein was similar in FHA and control subjects. We postulate that increased turnover rate of triglyceride-rich lipoproteins due to high LPL activity may be an important factor leading to the elevation of HDL-C in FHA. The highly significant positive correlation between HDL2-C and PH-LPL provides strong clinical evidence for the theory that HDL2 is formed during the hydrolysis of triglycceride-rich lipoproteins. The high concentration of HDL2 apo CII in FHA subjects may be caused by increased catabolism of triglyceride-rich lipoproteins in the presence of high endothelial LPL, with transfer of apo CII from very low to high density lipoproteins.
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PMID:Post-heparin plasma lipoprotein and hepatic lipases. Relationships to high density lipoprotein cholesterol and to apolipoprotein CII in familial hyperalphalipoproteinemic and in normal subjects. 742 98

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