Biomedical subjects

G Lepage

Publications and source records attributed to G Lepage.

At least 37 records · Page 2Linked to original sources

PubMed1995

Bile formation and hepatic plasma membrane composition in guinea-pigs and rats.

We compared bile formation, and biliary and liver plasma membrane composition in guinea-pigs and rats in an attempt to explain the observation that the bile flow rate and the bile acid independent fraction of bile flow (BAIF) in guinea-pigs is about five to seven times higher than in rats. Analysis of electrolytes in bile showed that bicarbonate was significantly [acid] higher in guinea-pigs while Cl-, phosphate and Ca2+ were markedly lower than in rats. High bile independent secretion in guinea-pigs was associated with a significantly lower concentration of total bile acid, phospholipid and cholesterol than in rats. Bile acid distribution studies showed that glycine conjugated chenodeoxycholate and ketolithocholate were the main bile acids in guinea-pigs, while taurine conjugated cholate and muricholate were the predominant bile acids in rats. Total fatty acid analysis of bile indicated that in rats the major fatty acids were palmitic acid (C16:0) and linoleic acid (C18:2, n-6). In guinea-pigs, the contribution of these fatty acids was lower than in rats and compensated with a significantly higher percentage of oleic acid (C18:1, n-9). Concentrations of anionic polypeptide fraction (APF), an acidic calcium binding apoprotein closely associated with biliary phospholipid and cholesterol secretion was also significantly lower in guinea-pigs. Canalicular plasma membrane analysis showed that as compared with rats, specific activities of Na+,K+ ATPase, and cholesterol and phospholipid content were markedly lower in guinea-pigs.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphatases↗

PubMed1995

Beta-1,2-linked oligomannosides from Candida albicans act as signals for tumor necrosis factor alpha production.

Different cell wall components from Candida albicans have been shown to stimulate murine macrophages for tumor necrosis factor alpha (TNF-alpha) secretion. All of these molecules contain beta-1,2-oligomannosides. In order to examine their role in TNF-alpha production, acid-labile oligosaccharides, released from C. albicans VW32 cell wall phosphopeptidomannan by mild acid hydrolysis, and previously shown to correspond to homopolymers of beta-1,2-linked mannopyranosyl units, were separated by gel filtration chromatography according to their degree of polymerization. Murine macrophages incubated with purified oligomannosides (M2 to M8) released TNF-alpha to an extent which was dependent on, although not directly correlated with, the length of the mannosyl chain. Slight activity was observed with M4 and M5; M6 and M7 had virtually no effect, whereas M8 was associated with strong TNF-alpha release. This effect of M8 was dose dependent and was not altered by polymyxin B, known to interfere with lipopolysaccharide-induced TNF-alpha production. These results suggest that stimulation of TNF-alpha release by C. albicans glycoconjugates containing beta-1,2-linked oligomannosides may be due, at least in part, to the presence of these components.

Animals↗

PubMed1994

The potential of the hydrocarbon breath test as a measure of lipid peroxidation.

The straight chain aliphatic hydrocarbons ethane and pentane have been advocated as noninvasive markers of free-radical induced lipid peroxidation in humans. In in vitro studies, the evolution of ethane and pentane as end products of n-3 and n-6 polyunsaturated fatty acids, respectively, correlates very well with other markers of lipid peroxidation and even seems to be the most sensitive test available. In laboratory animals the use of both hydrocarbons as in vivo markers of lipid peroxidation has been validated extensively. Although there are other possible sources of hydrocarbons in the body, such as protein oxidation and colonic bacterial metabolism, these apparently are of limited importance and do not interfere with the interpretation of the hydrocarbon breath test. The production of hydrocarbons relative to that of other end products of lipid peroxidation depends on variables that are difficult to control, such as the local availability of iron(II) ions and dioxygen. In addition, hydrocarbons are metabolized in the body, which especially influences the excretion of pentane. Because of the extremely low concentrations of ethane and pentane in human breath, which often are not significantly higher than those in ambient air, the hydrocarbon breath test requires a flawless technique regarding such factors as: (1) the preparation of the subject with hydrocarbon-free air to wash out ambient air hydrocarbons from the lungs, (2) the avoidance of ambient air contamination of the breath sample by using appropriate materials for sampling and storing, and (3) the procedures used to concentrate and filter the samples prior to gas chromatographic determination. For the gas chromatographic separation of hydrocarbons, open tubular capillary columns are preferred because of their high resolution capacity. Only in those settings where expired hydrocarbon levels are substantially higher than ambient air levels might washout prove to be unnecessary, at least in adults. Although many investigators have concentrated on one marker, it seems preferable to measure both ethane and pentane concurrently. The results of the hydrocarbon breath test are not influenced by prior food consumption, but both vitamin E and beta-carotene supplementation decrease hydrocarbon excretion. Nevertheless, the long-term use of a diet high in polyunsaturated fatty acids, such as in parenteral nutrition regimens, may result in increased hydrocarbon exhalation. Hydrocarbon excretion slightly increases with increasing age. Short-term increases follow physical and intellectual stress and exposure to hyperbaric dioxygen.(ABSTRACT TRUNCATED AT 400 WORDS)

Basal Metabolism↗

PubMed1994

S-adenosylmethionine prevents total parenteral nutrition-induced cholestasis in the rat.

Both an excess and an imbalance of amino acids have been associated with total parenteral nutrition-induced cholestasis. The present study was undertaken to further our understanding of this condition in light of observations that methyl donor amino acids may be protective. Rats were maintained on Travasol (3.4 g amino acids/24 h) and dextrose (10.2 g/24 h) with and without the "active methyl" S-adenosylmethionine at a dose of 75 mg/kg/24 h for 5 days, and compared to control rats on dextrose alone (10.2 g/24 h) with free access to rat chow. Bile flow (microliters/min) was lower (p < 0.025) in the Travasol (8.65 +/- 0.78) than in the control group (12.30 +/- 0.52) and was restored in the Travasol+S-adenosylmethionine animals (11.42 +/- 10). Furthermore, the bile acid secretory rate (mumol/h) was higher (p < 0.05) with S-adenosylmethionine (23.34 +/- 3.71) than without S-adenosylmethionine (14.16 +/- 2.19). As expected, the molar ratio of biliary cholesterol was lower (p < 0.005) in both total parenteral nutrition groups. However, in the total parenteral nutrition group without S-adenosylmethionine, there was also a decrease in the molar ratio of phospholipids which correlated well with the bile acid secretory rate. Analysis of liver plasma membranes showed that a lower activity of Na+K(+)-ATPase (mumol Pi/mg protein/h) (p < 0.005) in the Travasol animals (6.26 +/- 0.53) was restored to control values (15.20 +/- 1.43) by the addition of S-adenosylmethionine (17.07 +/- 2.87). In the three groups, a close correlation was observed between Na+K(+)-ATPase activity and bile flow.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗

PubMed1994

Clentiazem, diltiazem, and cold cardioplegia in isolated ischemic rabbit hearts: relation between additive cardioprotection, physicochemical properties, and preservation of myocardial lipid components.

Diltiazem is known to exert significant cardioprotection, but its efficacy under hypothermic conditions has not been documented. Because of its lipophilicity and its better tissue penetration, clentiazem, a chlorobenzothiazepine derivative of diltiazem, may offer cytoprotection additive to cold cardioplegia. We investigated the cardioprotective actions of clentiazem and diltiazem (10(-8) and 10(-6) M) when added to cold cardioplegia (myocardial temperature of 10 degrees-12 degrees C), in isolated rabbit heart subjected to 90-min global ischemia. Functional recovery was assessed by measuring left ventricular developed pressure (LVDP), coronary flow (CF) and heart rate (HR). To explore the potential beneficial mechanisms of these agents, we measured myocardial lipids and total calcium at the end of a 30-min period of reperfusion as well as their myocardial accumulation. Addition of 10(-8) M clentiazem to cold cardioplegia resulted in significant improvement in mechanical recovery (postischemic LVDP of 88.5 mm Hg with cardioplegia alone vs. 105.5 mm Hg with added clentiazem at 25 mm Hg diastolic pressure, DP). The additive cardioprotection afforded by clentiazem appeared to be concentration dependent since significant cardiodepression (postischemic LVDP of 79.8 mm Hg and 18% reduction in HR) was observed at a higher concentration (10(-6) M) and these effects were correlated with myocardial accumulation of the drug. The additive cardioprotective effect of clentiazem appeared to be structure related because diltiazem at both 10(-8) and 10(-6) M concentrations offered no benefits in addition to cold cardioplegia. These results indicate that the additive cardioprotection observed with 10(-8) M clentiazem could be related to its coronary vasodilator action since it reversed the cold cardioplegia-induced attenuation of hyperemic CF at reperfusion. Other factors must be involved, however, because addition of 10(-6) M diltiazem resulted in increased postischemic CF but without improving myocardial recovery. The functional protection offered by 10(-8) M clentiazem was associated with preservation of myocardial lipid components. Myocardial cholesterol content, which is essential for maintenance of membrane integrity, was preserved in that group, whereas a loss was observed in groups treated with cardioplegia alone and in the other treated groups. Total myocardial phospholipids were preserved in groups receiving 10(-8) M clentiazem plus cold cardioplegia or cold cardioplegia alone. A reduction in plasmalogen content, the predominant myocardial phospholipid species, and an increase in total myocardial calcium were noted only in ischemic hearts that received neither cardioplegia nor benzothiazepines, suggesting that cold cardioplegia is sufficient to prevent irreversible damage. Clentiazem affords cardioprotective benefits additive to cold cardioplegia.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1994

The Candida albicans phospholipomannan induces in vitro production of tumour necrosis factor-alpha from human and murine macrophages.

We have previously identified a Candida albicans 14,000-18,000 MW antigen reacting with anti-beta-1,2-linked oligomannosides antibodies as being a phospholipomannan (PLM). Because of the structural similarities between the C. albicans PLM and lipophosphoglycans from various microbial pathogens known to be potent tumour necrosis factor-alpha (TNF-alpha) inducers, we investigated the PLM ability to induce TNF-alpha. Incubation of human monocytic cells THP-1 with PLM led to dose-dependent production of TNF-alpha that was significantly increased by prestimulation of the cells with interferon-gamma (IFN-gamma). Production of TNF-alpha by macrophages under PLM stimulation was confirmed by using macrophages elicited from the mouse peritoneal cavity. In all investigated conditions, PLM-induced TNF-alpha production differed significantly in both kinetics and dose dependence from lipopolysaccharide (LPS) induction used as control. It appears, therefore, that the C. albicans PLM shares functional homologies with microbial lipophosphoglycans identified as pathogenicity factors, although prestimulation of the target cells was required for the PLM-derived opportunistic pathogen to trigger the cytokine network.

Animals↗

PubMed1993

Lipoprotein abnormalities associated with cholesteryl ester transfer activity in cystic fibrosis patients: the role of essential fatty acid deficiency.

The purpose of this study was to elucidate the roles of lecithin:cholesterol acyltransferase (LCAT) and cholesteryl ester transfer protein (CETP) in the lipoprotein derangement of cystic fibrosis (CF) patients with respect to their essential fatty acid (EFA) status. Triglyceride enrichment and cholesteryl ester (CE) depletion were observed in the lipoproteins of 22 CF patients. The abnormal chemical composition was more severe in 12 EFA-deficient (EFAD) than in 10 EFA-sufficient (EFAS) patients. Expressed in nmol.L-1.h-1, LCAT activity was higher (P < 0.05) in both EFAS (mean +/- SE, 92.7 +/- 1.9) and EFAD (108.8 +/- 3.0) patients than in control subjects (65.2 +/- 0.9). An equal CE transfer was recorded in the lipoprotein-deficient serum, as a source of CETP activity, in all groups studied by using normal exogenous low-density lipoprotein (LDL) and high-density lipoprotein (HDL). However, in contrast to the maximal amount of CE transferred from endogenous HDL to endogenous apolipoprotein B (apo B) in control subjects, a reduction in CETP activity was seen in CF patients and more pronounced in the EFAD group. These findings indicate that impaired lipoprotein composition may have marked effects on the transfer of CE between HDL and apo B in EFAD CF patients.

Adolescent↗

PubMed1993

Beneficial effects of fish-oil supplements on lipids, lipoproteins, and lipoprotein lipase in patients with glycogen storage disease type I.

Glycogen storage disease type I (GSD-I) is frequently complicated by severe hyperlipoproteinemia and the increased potential risk of premature atherosclerosis. The effects of fish-oil supplementation [MaxEPA, 10 g.(1.73 m2)-1 for 3 mo] were investigated prospectively in seven hyperlipoproteinemic patients with GSD-I. Hypertriglyceridemia and hypercholesterolemia improved after 3 mo of fish-oil treatment, decreasing 49% (P < 0.005) and 23%, respectively. This was accompanied by a reduction in both low-density-lipoprotein (LDL) cholesterol (25%, P < 0.03) and apolipoprotein B (40%) and by increased high-density-lipoprotein increased (HDL) cholesterol (30%, P < 0.002) and apolipoprotein A-I (31%, P < 0.05). Low pretreatment ratios of HDL to total cholesterol and HDL to LDL, indicators of elevated atherosclerosis risk, increased significantly (P < 0.05). Plasma lipoprotein profile as well as lipoprotein composition [triglyceride (TG) enrichment and cholesteryl depletion] improved. Reduced TG concentrations were due to enhanced fat catabolism, as evidenced by the significantly increased hepatic and extrahepatic lipoprotein lipase activity (P < 0.05). Withdrawal of fish oil for 3 mo was associated with a return to pretreatment abnormalities in plasma lipids and lipoproteins. Fish-oil supplementation thus improves the hyperlipoproteinemia in GSD-I and may significantly reduce the risk of premature atherosclerotic cardiovascular disease.

Adolescent↗

PubMed1993

Isolation and preliminary characterization of the 14- to 18-kilodalton Candida albicans antigen as a phospholipomannan containing beta-1,2-linked oligomannosides.

Western blot (immunoblot) analysis of Candida albicans germ tube extracts has demonstrated the probable presence of beta-1,2-linked oligomannosides acting as epitopes distributed over a 14- to 18-kDa antigen unreactive to concanavalin A. These conclusions about the existence of these non-mannan-associated oligomannoside species were reinforced in the present study by the demonstration of reactivity of factor serum 5 (Iatron Laboratories) with the same antigen. A monoclonal antibody which reacted in an enzyme immunoassay with beta-1,2-linked oligomannosides converted into neoglycolipids and in Western blotting with the 14- to 18-kDa antigen from yeast and germ tubes, through metaperiodate-sensitive epitopes, was used for further characterization of the molecule. Reducing agents and strong protease digestion, which have deleterious effects on C. albicans proteins and mannoproteins, affected neither the antigenicity nor the relative molecular weight of the molecule. Western blots performed after migration of protease-treated extracts in polyacrylamide gels without sodium dodecyl sulfate (SDS) showed that the 14- to 18-kDa antigen could be negatively charged, whereas metabolic radiolabeling demonstrated that these charges could originate, at least in part, from the presence of phosphorus within the molecule. Chloroform-methanol-water extraction of protease-resistant material led to purification of the 14- to 18-kDa antigen, as determined by SDS-polyacrylamide gel electrophoresis and Western blotting. Metabolic radiolabeling with mannose confirmed the presence of these sugar residues within the purified 14- to 18-kDa antigen (despite its nonreactivity to concanavalin A), whereas radiolabeling with palmitic acid demonstrated its lipopolysaccharidic nature. Together, these results led to the conclusion that the 14- to 18-kDa antigen is a phospholipomannan.

Antibodies, Fungal↗

PubMed1993

Liver membrane composition after short-term parenteral nutrition with and without taurine in guinea pigs: the effect to taurine.

Having recently demonstrated that taurine supplementation prevents total parenteral nutrition (TPN)-induced cholestasis, we chose to use this model to examine plasma membrane composition in relation to bile formation. Male guinea pigs received daily a mixture of glucose and of the amino acid solution Travasol with or without added taurine (1.2 mM). After 3 days, bile was collected and liver plasma membrane fractions enriched in sinusoidal lateral membrane and bile canalicular membrane domains were isolated. In animals receiving TPN alone, bile flow and biliary secretory rate of bile acid and bicarbonate decreased significantly compared with controls. Although membrane ATPases (Na+K+ and Mg+) were unchanged, TPN induced an increase in the lipid to protein ratio and a decrease of polyunsaturated fatty acids, in conjunction with a higher content of diene conjugates in sinusoidal lateral membrane fractions. Taurine corrected these changes and, in addition, reduced significantly the cholesterol to phospholipid ratio in both membrane fractions. The data show that changes in liver cell membranes occur in TPN-induced cholestasis and suggest that free radical injury may play a role. As taurine prevented cholestasis as well as membrane changes, it is suggested that taurine should be added to amino acid solutions used for parenteral nutrition.

Amino Acids↗

PubMed1992

Intraluminal and intracellular phases of fat absorption are impaired in essential fatty acid deficiency.

The structure and function of enterocyte membranes are particularly sensitive to the degree of fatty acid saturation. The objective of the present study was to assess intestinal fat transport in essential fatty acid (EFA)-deficient animal models. Both the digestive and absorptive phases leading to the formation and the secretion of triglyceride (TG)-rich lipoproteins were investigated. After an intraduodenal fat infusion, the percentage increase of plasma TG over fasting values was examined over a period of 4 h in two groups of control and EFA-deficient rats. Lower values at 1 and 2 h (P less than 0.05) were observed in EFA-deficient rats, suggesting fat malabsorption. Likewise, postprandial chylomicronemia was diminished. In a separate group of rats, EFA deficiency was associated with reduced TG and chylomicron-TG transport into lymph. Although pancreatic lipase activity did not change (47.1 vs. 46.2 mumol free fatty acids.mg protein-1.h-1), bile flow was decreased over the 8-h period of collection. Concomitantly, a significant decline (nmol.min-1.g liver-1, P less than 0.05) was discernible in the biliary secretory rate of bile salts (14.09 +/- 2.13 vs. 35.09 +/- 3.73), phospholipids (7.01 +/- 0.61 vs. 11.79 +/- 1.65) and cholesterol (0.19 +/- 0.01 vs. 0.83 +/- 0.06). In vitro studies, utilizing everted sacs incubated with mixed micelles, revealed that EFA-deficient jejunal segments of rats incorporated and esterified less [14C]oleic acid (21 and 32%, respectively). Moreover, the synthesis and secretion of TG-rich lipoproteins were found markedly reduced in mouse jejunal explant cultures. We conclude that EFA deficiency modifies both the intraluminal and intracellular phases of fat absorption.

Absorption↗

PubMed1992

The hydrocarbon breath test in the study of lipid peroxidation: principles and practice.

Lipid peroxidation has gained increasing interest in recent years as one of the more prominent features of free radical-induced damage in biology. The study of lipid peroxidation might increase our understanding of the etiology and pathophysiology of a great number of diseases. Ethane and pentane are among the numerous end-products of lipid peroxidation and although they represent only a small and possibly variable proportion of the total amount of peroxidized polyunsaturated fatty acids, their determination in head space or exhaled breath enables accurate assessment of oxidative stress both in vitro and in vivo. To date, the number of studies utilizing the hydrocarbon breath test as a marker of lipid peroxidation in humans is small. Technical difficulties are among the main reasons for the limited use of this method. An appropriate washout period, the use of the right materials, the scrupulous avoidance of air contamination, adequate preinjection concentrations of the samples, and a sensitive gas chromatographic technique enable the accurate and reproducible measurement of hydrocarbons in human breath. The hydrocarbon breath test provides a noninvasive and extremely sensitive instrument for the assessment of oxidative stress status in adults as well as in children.

Breath Tests↗

PubMed1991

1H-NMR spectroscopy of manno-oligosaccharides of the beta-1,2-linked series released from the phosphopeptidomannan of Candida albicans VW-32 (serotype A).

Manno-oligosaccharides (DP 2 to greater than 15) were released by mild acid hydrolysis from the phosphopeptidomannan of a Candida albicans strain of A serotype (VW-32). Manno-oligosaccharides ranging from biose to heptaose were obtained in appreciable amount. Structural investigation of these oligosaccharides showed them to be of the beta-1,2-linked series. The occurrence of such compounds has already been reported in other strains of Candida albicans. We here report the assignment of the structural reporter groups of each of them, and general rules applicable for the 1H-NMR spectrum analysis of linear manno-oligosaccharide of general structure: Man(beta 1-2) [Man(beta 1-2)]nMan

Candida albicans↗

PubMed1991

Preparative steps necessary for the accurate measurement of malondialdehyde by high-performance liquid chromatography.

The need for a more specific, reliable, and reproducible technique for the measurement of malondialdehyde (MDA) has prompted modifications of currently available methods based on the formation and recovery of the complex between MDA and thiobarbituric acid (TBA). To 500 microliters of plasma or to 300 mg of liver homogenate, 2 ml of H2O and 500 microliters of 0.5% butylated hydroxytoluene in methanol were added to prevent further formation of MDA. Precipitation of proteins carried out with 200 microliters of 0.66 N H2SO4 and 150 microliters of 10% Na2WO4 (w/v) led to complete recovery of the MDA standard. Maximum formation of the MDA-TBA complex was obtained by adjusting the pH between 2.5 and 4.5 and heating the MDA-TBA mixture at 100 degrees C for 60 min. Extraction of the MDA-TBA complex was a critical step and proved complete with n-butanol at pH less than 0.75. It was then evaporated at 37 degrees C under nitrogen. The MDA-TBA complex solubilized in H2O was shown to be stable for at least 7 days. These preparative steps led to the detection of a single peak that on spectral analysis was identified as pure MDA-TBA. This procedure offers several advantages in terms of specificity, recovery, and reproducibility.

1-Butanol↗

PubMed1991

Taurine decreases fecal fatty acid and sterol excretion in cystic fibrosis. A randomized double-blind trial.

Patients with cystic fibrosis may still have a significant degree of steatorrhea despite adequate pancreatic enzyme supplementation. Taurine is a conditionally essential amino acid that possibly improves the micellar phase of fat digestion. Thirteen children with cystic fibrosis and a significant degree of steatorrhea (> 13 g/d) were enrolled in a randomized double-blind crossover study of taurine (30 mg/kg per day) in contrast to placebo for two successive 4-month periods. No difference was noted in height and weight velocity, lung function, vitamin A level, and essential fatty acid status. Twelve of the 13 patients showed a decrease in fecal fatty acid excretion (26.5 +/- 2.6 g/24 h vs 15.4 +/- 2.5 g/24 h), affecting mainly saturates and monounsaturates, and a decrease in total sterol excretion (1492.6 +/- 303 mg/24 h vs 1211.7 +/- 213.8 mg/24 h) while ingesting taurine. Taurine may be a useful adjunct in patients with cystic fibrosis and severe steatorrhea.

Adolescent↗

PubMed1990

Essential fatty acid deficiency mimicking porphyria cutanea tarda in a patient with chronic cholestasis.

Essential fatty acid deficiency was documented in a 3-year-old boy with chronic cholestasis secondary to paucity of intrahepatic bile ducts (Alagille's syndrome). Dietary management had consisted almost exclusively of a proprietary formula with over 80% of the fat as medium-chain triglycerides. The bullous lesions involved mostly sun-exposed areas and were diagnosed initially as being compatible with acquired porphyria cutanea tarda. Improvement followed correction of the fatty acid abnormalities with a polyunsaturated fat supplement administered orally. We postulate that the association of fatty acid deficiency and abnormal vitamin E status contributed to skin damage, possibly involving photosensitizing compounds poorly cleared by the markedly cholestatic liver.

Child, Preschool↗

PubMed1990

Combined (n-3 and n-6) essential fatty deficiency is a potent modulator of plasma lipids, lipoprotein composition, and lipolytic enzymes.

Essential fatty acids (EFA) are important structural and functional components of cell membranes. Their deficiency has been associated with several clinical and biochemical abnormalities. In the present study, the lipid profile as well as the concentration, composition, and metabolism of lipoproteins were examined in rats rendered EFA-deficient over a period of 12 weeks. Changes in plasma fatty acids mainly induced an increase of palmitoleic (16:1 n-7) and eicosatrienoic (20:3 n-9) acids, while linoleic (18:2 n-6), arachidonic (20:4 n-6), linolenic (18:3 n-3), and docosahexaenoic (22:6 n-3) acids were decreased. The results show increased concentrations of free fatty acids (FFA) (P less than 0.001), triglycerides (P less than 0.001), total cholesterol (P less than 0.02), free cholesterol (P less than 0.005), and phospholipids (P less than 0.05) when compared to pair-fed controls. Similar levels of cholesteryl esters were found in the two groups, and lecithin: cholesterol acyltransferase activity (nmol/100 microliters plasma per h) (8.98 +/- 1.44 vs 8.72 +/- 0.50) did not differ. On the other hand, postheparin extrahepatic lipoprotein lipase (LPL) activity was significantly (P less than 0.002) decreased (5.96 +/- 0.29 vs 7.29 +/- 0.68 mumol FFA/ml per h) and could account for the hypertriglyceridemia as well for the relative triglyceride enrichment of very low density lipoprotein, intermediate density lipoprotein, and low density lipoprotein particles. This enzymatic depletion of LPL was mainly due to the adipose tissue, since a higher level (P less than 0.001) of hepatic lipase (325.8 +/- 16.0 vs 130.8 +/- 9.5 nmol FFA/mg protein per h) was found in liver acetone powder extracts.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1989

Porcine versus pericardial bioprostheses: a comparison of late results in 1,593 patients.

From 1976 to 1988, 1,593 patients underwent valve replacement with a porcine (878 patients) or a pericardial bioprosthesis (715 patients). There were 701 aortic, 678 mitral, and 214 multiple-valve replacements. Follow-up was obtained for 1,559 patients (98%). Early mortality was 9% (79 patients) in the porcine valve group and 5% (37 patients) among patients with a pericardial valve (p less than 0.01). Late survival after replacement with porcine valves was 80% +/- 1% and 62% +/- 3% at 5 and 10 years, respectively. With pericardial valves, 5-year survival was 79% +/- 2%. Among valve-related complications, rates of freedom from thromboembolism, endocarditis, and hemorrhage after 6 years were similar for both valve groups. Freedom from reoperation at 6 years was also similar after aortic (96% versus 91%) or multiple-valve replacement (95% versus 88%). However, for mitral valve replacement, freedom from reoperation was significantly better with porcine valves than with pericardial valves at 6 years (92% versus 68%; p less than 0.001). This difference was mainly due to the Ionescu-Shiley valve, which accounted for 83% of primary tissue failures among pericardial bioprostheses implanted in the mitral position (10/12 patients). After 6 years, freedom from primary tissue failure of mitral valves was 92% +/- 2% with porcine and 70% +/- 11% with pericardial bioprostheses (p less than 0.0001). The degree of clinical improvement among survivors was similar with both valve types. Thus, in the aortic position, pericardial valves compare with porcine valves up to 6 years, whereas in the mitral position, the durability of the former is significantly less, mainly because of the suboptimal performance of the Ionescu-Shiley pericardial bioprosthesis.

Adolescent↗