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Biomedical subjects

J Delarue

Publications and source records attributed to J Delarue.

At least 19 recordsLinked to original sources
PubMed2003

Fish oil prevents the adrenal activation elicited by mental stress in healthy men.

OBJECTIVES: A diet rich in n-3 fatty acids (fish oils) is associated with reduced risks of cardiovascular and metabolic diseases, but the mechanisms remain incompletely understood. Sympathoadrenal activation is postulated to be involved in the pathogenesis of these diseases, and may be inhibited by n-3 fatty acids. We therefore evaluated the effects of a diet supplemented with n-3 fatty acids on the stimulation of the sympathetic nervous system and of stress hormones elicited by a mental stress. METHODS: Seven human volunteers were studied on two occasions, before and after 3 weeks of supplementation with 7.2 g/day fish oil. On each occasion, the concentrations of plasma cortisol, and catecholamines, energy expenditure (indirect calorimetry), and adipose tissue lipolysis (plasma non esterified fatty acid concentrations) were monitored in basal conditions followed by a 30 min mental stress (mental arithmetics and Stroop's test) and a 30 min recovery period. RESULTS: In control conditions, mental stress significantly increased heart rate, mean blood pressure, and energy expenditure. It increased plasma epinephrine from 60.9 +/- 6.2 to 89.3 +/- 16.1 pg/ml (p<0.05), plasma cortisol from 291 +/- 32 to 372 +/- 37 micromol/l (p<0.05) and plasma non esterified fatty acids from 409 +/- 113 to 544 +/- 89 micromol/l (p<0.05). After 3 weeks of a diet supplemented with n-3 fatty acids, the stimulation by mental stress of plasma epinephrine, cortisol, energy expenditure, and plasma non esterified fatty acids concentrations, were all significantly blunted. CONCLUSION: Supplementation with n-3 fatty acids inhibits the adrenal activation elicited by a mental stress, presumably through effects exerted at the level of the central nervous system.

Adult↗
PubMed2001

Acute metabolic effects of dialysis fluids during CAPD.

Because the osmotic agents currently used for peritoneal dialysis, ie, glucose or amino acids, are also substrates, a metabolic transfer occurs during their peritoneal absorption. After the delivery of a 3.86% glucose dialysis solution, about 100% of the glucose absorbed through the peritoneal is oxidized. So, this glucose contributes fully to the energy load of the patients. Peritoneal glucose delivery also entertains hyperglycaemia and hyperinsulinaemia as compared to oral glucose. When compared to healthy subjects, oral glucose in continuous ambulatory peritoneal dialysis (CAPD) patients induces a higher glycaemic and insulinaemic response. This traduces insulin resistance in CAPD patients even after months of that renal replacement therapy. When amino acids are used in place of glucose in dialysis solution, they stimulate whole body protein turnover and are used mainly for protein synthesis. When a meal is coingested, protein breakdown is inhibited which reinforces the positive effect of the solution on protein balance.

Administration, Oral↗
PubMed2000

Study of interaction phenomena between aroma compounds and carbohydrate matrixes by inverse gas chromatography.

Besides the conventional techniques used for the investigation of food-flavor interactions, inverse gas chromatography (IGC) may provide a useful tool for the direct assessment of the retention of aroma compounds in a matrix. IGC consists of single reference compound injections at a fixed temperature onto a column which stationary phase is the material of interest. We have applied this technique to high amylose corn starch, wheat starch, and beta-cyclodextrin matrixes, using aroma compounds presenting various functional groups. Low energy interactions were measured which may result from polar or hydrophobic binding. Starch behaved under these conditions as a polar chromatographic phase. We also focused on the influence of a physical modification of the starch on its retention properties toward 3,7-dimethyl-2,6-octadien-1-al. Retention was found to be greater after a specific thermal treatment. As checked by DSC (differential scanning calorimetry) and DMTA (dynamic mechanical and thermal analysis), the observed changes are believed to be related to the glass transition of the starch. For the time being, the dehydration of the matrix associated with the lack of control of the relative humidity within the column is the main restriction to this technique.

Chromatography, Gas↗
PubMed2000

[Cardiac abnormalities in a prospective series of 40 patients with type 2 diabetes].

Cardiovascular mortality, the principal cause of early death in diabetics, is multifactorial. A prospective study was undertaken to analyse the different factors of excess cardiac complications in 40 patients with type 2 diabetes, whatever the symptomatology, by making an inventory of the cardiac abnormalities (systolic and diastolic left ventricular function, left ventricular hypertrophy, abnormalities of myocardial perfusion, heart rate variability and arrhythmias). Patients underwent 24 hour Holter monitoring, high amplification signal averaged electrocardiography, echocardiography, Thallium scintigraphy with a dipyridamole test followed by coronary angiography when positive. Patients were aged 60 +/- 8 years, diabetics for 11.8 +/- 6.8 years, and had associated cardiovascular risk factors: 85% were obese, 75% were hypertensive, 62.5% had hypercholesterolaemia and 60% were smokers. The HbA1C was 9.2 +/- 19%. An increased left ventricular mass was observed in 34.2% of patients. The left ventricular ejection fraction was normal (59.1 +/- 6.8%); 69.7% of patients had left ventricular diastolic dysfunction. Reduced heart rate variability was observed in 51.8% of cases. Late ventricular potentials were recorded on high amplification signal averaging in 39.5% of patients; 25.6% had significant ventricular extrasystoles and 52.2% had atrial extrasystoles. Twelve patients (45%) underwent Thallium myocardial scintigraphy with a positive dipyridamole test, 8 of whom had coronary lesions on angiography. The excess cardiac complications of diabetes is mainly due to ischaemic heart disease aggravated by autonomic neuropathy, left ventricular diastolic dysfunction, arrhythmias and left ventricular hypertrophy. In future, larger series are required to demonstrate that this detection can guide therapeutic intervention and reduce cardiac morbidity and mortality of diabetics.

Adult↗
PubMed1999

Effects of an amino acid dialysate on leucine metabolism in continuous ambulatory peritoneal dialysis patients.

BACKGROUND: Protein-energy malnutrition is frequent in continuous ambulatory peritoneal dialysis (CAPD) patients. The use of amino acids in the dialysate could improve the protein balance, especially if associated to a concomitant energy intake. METHODS: A 1.1% amino acid solution for peritoneal dialysis was administered to CAPD patients over 30 minutes during concomitant absorption of 600 ml water (control study) or of a 600 kcal meal/600 ml. Leucine metabolism was studied using the combination of intravenous [2H3] and intraperitoneal [13C] leucine. RESULTS: The rate of leucine appearance was stimulated by 56 and 53% (control and meal) at 45 minutes. The rates of leucine appearance and disappearance were lower from 180 to 300 minutes during the meal versus control study (P < 0.05). Proteolysis was unaffected during the control study and was inhibited by 25% during the meal study (P < 0.05). During the five-hour cycle dialysis with or without a meal, 80% of the leucine administered into the peritoneum was absorbed. Forty-one percent was retained in the splanchnic bed. Forty-three percent was used for protein synthesis, and 16% was oxidized. CONCLUSIONS: This amino acids solution is efficaciously utilized for protein synthesis in CAPD patients with no effect on protein breakdown. The concomitant ingestion of a carbohydrate-lipid meal inhibits protein breakdown and reinforces a positive effect of the amino acids solution on protein balance.

Adult↗
PubMed1998

Long-term supplementation of culture medium with essential fatty acids alters alpha-linolenic acid uptake in Caco-2 clone TC7.

We investigated the influence of four different culture media: 20% fetal bovine serum (FBS), 5% FBS, 5% FBS supplemented with 10 mg x L(-1) linoleic acid (18:2(n-6)) or alpha-linolenic acid (18:3(n-3)) on alpha-linolenic acid apical uptake in clone TC7 of human intestinal Caco-2 cell line. Neither cellular viability nor cell monolayer integrity and permeability were altered by the four culture conditions. Our results show that the different culture media led to changes in alpha-linolenic acid maximal rate of uptake (Vmax) but did not alter the apparent transport constant (Km). Reducing FBS concentration from 20% to 5% increased significantly the rate of alpha-linolenic acid uptake, which was further increased by supplementation of the medium with 18:2(n-6) or 18:3(n-3). Supplementation with essential fatty acids led to a marked enrichment of brush-border membrane phospholipids in polyunsaturated fatty acids of the corresponding series and decreased significantly the levels of monounsaturated fatty acids. Saturated fatty acids, unsaturation index, and cholesterol/fatty acid ratios were unchanged. No clear relation could be established between the changes in membrane lipid composition and the alterations of alpha-linolenic acid uptake. These results indicate a weak influence of membrane lipid composition in the modulation of the uptake. Therefore, the increase of uptake following long-term supplementation of TC7 cells with essential fatty acids could be attributed to an increase of the expression of membrane protein(s) involved in the apical uptake of long-chain fatty acids. This remains to be established.

Animals↗
PubMed1997

Mechanisms and kinetics of alpha-linolenic acid uptake in Caco-2 clone TC7.

The uptake kinetics of alpha-linolenic acid (18:3(n - 3)), an essential fatty acid, were investigated in the human intestinal cell line Caco-2. Four clones (PD10, PF11, PD7 and TC7) from the heterogeneous parental Caco-2 cells population were used. After a screening step using isolated cells, the TC7 clone was selected for the study of alpha-linolenic acid uptake. [1-(14)C]linolenic acid dissolved in 10 mM taurocholate was presented to the microvillus plasma membrane (apical side) of TC7 differentiated cells, grown on a semi-permeable polycarbonate membrane. The results show that the initial rate of uptake is not a linear function of the 18:3(n- 3) monomer concentration in the incubation medium. In the monomer concentration range studied (0.2 to 36 microM) apical uptake was saturable and followed Michaelis-Menten kinetics (V(max) = 15.4 +/- 0.6 nmol/mg protein per min, K(m) = 14.3 +/- 1.3 microM). In addition, it was temperature- and energy-dependent but was apparently unaffected by the sodium gradient and intracellular metabolic fate of 18:3(n - 3). Excess of unlabeled saturated or unsaturated long chain fatty acids (C16 to C22) led to a 27-68% reduction of [1-(14)C]linolenic acid uptake. Likewise basolateral uptake was saturable (V(max) = 4.9 +/- 0.7 nmol/mg protein per min, K(m) = 8.7 +/- 2.9 microM). These facts argue in favour of the existence in these human intestinal cells of a carrier-mediated transport system for alpha-linolenic acid and probably other long chain fatty acids as well.

Adenocarcinoma↗
PubMed1997

Effect of dietary fish oil on body fat mass and basal fat oxidation in healthy adults.

OBJECTIVE: To investigate whether the substitution of fish oil for visible fats in a control diet (52% carbohydrates, 16% protein, 32% fat; P:S 0.2) influences body fat mass and substrate oxidation in healthy adults. DESIGN: Six volunteers (5 men; 23 +/- 2 y; BMI: 21.9 +/- 1.6) were fed a control diet (C) ad libitum during a period of three weeks and, 10-12 weeks later, the same diet where 6 g/d of visible fat were replaced by 6 g/d of fish oil (FO) for another three weeks. RESULTS: Energy intakes (IKA-calorimeter) were unchanged. Body fat mass (Dual-energy X-ray absorptiometry) decreased with FO (-0.88 +/- 0.16 vs -0.3 +/- 0.34 kg; FO vs C; P < 0.05). When adjusted for lean body mass (Ancova), resting metabolic rate (indirect calorimetry) was unchanged. Basal respiratory quotient decreased with FO (0.815 +/- 0.02 vs 0.834 +/- 0.02; P < 0.05) and basal lipid oxidation increased with FO (1.06 +/- 0.17 vs 0.87 +/- 0.13 mg kg(-1) min(-1); P < 0.05). CONCLUSION: Dietary FO reduces body fat mass and stimulates lipid oxidation in healthy adults.

Adult↗
PubMed1997

Effects of adrenergic blockade on hepatic glucose production during ethanol administration.

Acute ethanol administration stimulates sympathetic nervous system activity. The present study was designed to determine whether this sympathetic activation affects glycogenolysis and total hepatic glucose production (HGP) during ethanol-induced inhibition of gluconeogenesis. Nineteen volunteers participated in four protocols. Two protocols aimed to study--using combined infusion of [6,6-2H2]glucose and [U-13C]glucose, VCO2 and 13CO2 measurements--the effects of ethanol infusion alone (n = 10) or with propranolol (n = 6) or phentolamine infusion (n = 4) on HGP, glucose disposal (Rd), glucose oxidation [13C]Glcox and non-oxidative glucose disposal (NOGD = Rd - [13C]Glcox). The fourth protocol assessed the effects of saline infusion alone on HGP. Using ethanol, HGP decreased by 23%, Rd by 20% and glycaemia by 9% (all P < 0.001); heart rate increased by 10%, whereas blood pressure remained unchanged. The effects were not observed with saline, except a slight (10%) decrease in HGP (P < 0.01 vs. ethanol). Ethanol did not affect [13C]Glcox but decreased NOGD by 73% (P < 0.001). Propranolol or phentolamine did not alter any of the effects of ethanol on glucose metabolism, but decreased mean arterial pressure. Propranolol prevented the ethanol-induced increase in heart rate. In conclusion, ethanol decreased blood glucose by decreasing HGP, presumably by inhibiting gluconeogenesis. Sympathetic activation prevented the decrease in blood pressure produced by ethanol but did not stimulate glycogenolysis.

Adrenergic Antagonists↗
PubMed1997

Effects of dexamethasone on hepatic glucose production and fructose metabolism in healthy humans.

This study was designed to determine whether glucocorticoids alter autoregulation of glucose production and fructose metabolism. Two protocols with either dexamethasone (DEX) or placebo (Placebo) were performed in six healthy men during hourly ingestion of[13C]fructose (1.33 mmol.kg-1.h-1) for 3 h. In both protocols, endogenous glucose production (EGP) increased by 8 (Placebo) and 7% (DEX) after fructose, whereas gluconeogenesis from fructose represented 82 (Placebo) and 72% (DEX) of EGP. Fructose oxidation measured from breath 13CO2 was similar in both protocols [9.3 +/- 0.7 (Placebo) and 9.6 +/- 0.5 mumol.kg-1.min-1 (DEX)]. Nonoxidative carbohydrate disposal, calculated as fructose administration rate minus net carbohydrate oxidation rate after fructose ingestion measured by indirect calorimetry, was also similar in both protocols [5.8 +/- 0.8 (Placebo) and 5.9 +/- 2.0 mumol.kg-1.min-1 (DEX)]. We concluded that dexamethasone 1) does not alter the autoregulatory process that prevents a fructose-induced increase in gluconeogenesis from increasing total glucose production and 2) does not affect oxidative and nonoxidative pathways of fructose. This indicates that the insulin-regulated enzymes involved in these pathways are not affected in a major way by dexamethasone.

Adult↗
PubMed1996

Effects of fish oil on metabolic responses to oral fructose and glucose loads in healthy humans.

This study examines the effect of the substitution of 6 g/day of fish oil in a saturated diet on glucose and fructose metabolism in healthy humans. Five subjects were submitted to two 3-wk controlled-diet periods (polyunsaturated/saturated = 0.21). During one period, 6 g/day of fat used for dressing were replaced by 6 g/day of fish oil [1.1 g/day of 20:5 (n-3) fatty acids and 0.7 g/day of 22:6 (n-3) fatty acids]. At the end of each period the subjects ingested a 1 g/kg fructose or glucose load 2 days apart. Plasma glucose fluxes were traced with the use of deuterated glucose and [U-13C]glucose. Substrate oxidation was measured by indirect calorimetry. Fish oil induced a 4% increase in basal and postload glycemia and a 40% decrease in insulinemia, whereas plasma C-peptide remained unaffected. Glucose fluxes were unaffected by fish oil, but carbohydrate (CHO) oxidation was reduced (fructose: 55.5 +/- 4.1 vs. 62.9 +/- 3.6 g/6 h; glucose: 36.7 +/- 4.7 vs. 50.5 +/- 4.7 g/6 h; all P < 0.05). Lipid oxidation was increased 35% by fish oil after both CHO loads. Nonoxidative glucose disposal was increased by fish oil (fructose: 9.4 +/- 2.5 vs. 2.9 +/- 1.1 g/6 h; glucose: 28.3 +/- 5.1 vs. 14.4 +/- 4.7 g/6 h; all P < 0.05). Fish oil could affect glucose transport and decrease CHO oxidation through the decrease in insulinemia and/or a specific effect on glycolytic pathway.

Administration, Oral↗
PubMed1996

Effects of free fatty acids on the metabolic response to oral fructose in lean healthy humans.

OBJECTIVE: To study the effects of an experimental increase in plasma FFA concentration on fructose to glucose conversion, total hepatic glucose output and glycaemic response to oral fructose. SUBJECTS: Six healthy subjects (three men, three women; age: 24.3 +/- 2.3 years; BMI: 21.6 +/- 0.8 kg/m2). DESIGN: Each subject absorbed 0.5 g/kg of 13C-enriched fructose and randomly received either a triglyceride-heparin infusion or saline. MEASUREMENTS: Total hepatic glucose output was traced with 6,6-2H2-glucose. Appearance in plasma of glucose synthesized from fructose was calculated from the isotopic enrichment in 13C of plasma glucose. Substrates oxidation was assessed with indirect calorimetry. RESULTS: The triglycerides-heparin infusion increased FFA concentration before fructose as compared to saline (1086 +/- 40 vs 451 +/- 67 microM; p < 0.001) and lipid oxidation was 15% and 70% increased before and during fructose, respectively as compared to saline. Total hepatic glucose output, plasma appearance of glucose synthesized from fructose and glycaemic response were not affected. Glycogen storage over the first 3 h following fructose was increased (6.2 +/- 2.1 g vs 0.3 +/- 2.1 g; p < 0.01). CONCLUSION: Triglycerides-heparin infusion did not stimulate plasma glucose appearance from fructose. Liver glucose-6-phosphate could have been produced in excess and diverted towards glycogen synthesis.

Adult↗
PubMed1994

Glucose oxidation after a peritoneal and an oral glucose load in dialyzed patients.

Glucose oxidation and thermogenesis were studied after a peritoneal (P) and an oral (O) glucose load in nine chronically uremic patients undergoing continuous ambulatory peritoneal dialysis (CAPD) for 24.4 +/- 5.8 months. The O load (50 g) given was equivalent to the amount of glucose absorbed over six hours through the peritoneum of the subjects (51.7 +/- 3.3 g). Glucose oxidation and energy expenditure were obtained using indirect calorimetry in basal state and over the six hours following the glucose load. Glucose oxidation rate was higher from 60 to 180 minutes after O than after P (P < 0.05), with peak values of 3.85 +/- 0.28 mg.kg-1.min-1 and 2.80 +/- 0.17 mg.kg-1.min-1 respectively (P < 0.05). Cumulated glucose oxidation over six hours was 53.6 +/- 0.6 versus 47.0 +/- 3.4 g after O and P respectively (NS). Glucose-induced thermogenesis was 8.7 +/- 2.9% versus 5 +/- 1.9% after O and P, respectively (NS). The route of administration of glucose induces different kinetics of the glucose oxidation rate, but a similar amount of glucose absorbed either by the peritoneum or by the gut contributes in a similar extent to glucose and energy balance.

Absorption↗
PubMed1994

Anthropometric values in an elderly French population.

We compared anthropometric indices in samples of elderly people aged 65 years and over living in two French areas. The samples were divided into four age-groups (65-69, 70-74, 75-79 and over 80 years). We observed interregional differences in women aged 65-69 years and in men aged 65-74 years. Weight and anthropometric variables related to body fat percentage and to muscle mass showed a decline with age as already reported by others. We established anthropometric percentile values according to sex in pooled subjects when no integrated difference was found. The 50th percentile of arm circumference, muscle arm circumference and triceps skinfold was higher, and the 50th percentile of body mass index was lower than the one reported for the same indices from an elderly Welsh population. Our results show that an interregional difference in anthropometric indices exists in the elderly. The differences which are observed between our results and those reported from a British population emphasize the importance of establishing local values for the elderly population.

Aged↗
PubMed1994

Plasma lipids and alcohol consumption in alcoholic men: effect of withdrawal.

This study examines the effect of alcohol withdrawal on plasma lipids and particularly on HDL-cholesterol subfractions, in 18 middle-aged, clinically healthy but chronically drinking men, institutionalized for withdrawal therapy. Plasma lipids, total HDL and HDL3-cholesterol, Apo A-I and Apo B were assayed before and after 30-86 days of abstinence. A 38% decrease in mean total HDL-cholesterol levels was observed after withdrawal therapy (P = 0.0002), and this was due mainly to a drop in HDL3-cholesterol concentrations (-43%, P = 0.0002). The decrease in HDL2-cholesterol concentrations was also significant (-21%, P < 0.005) but less marked. These results were not dependent on quantities of alcohol ingested before therapy, on duration of hospitalization and on changes in dietary fat intake or smoking habits. Apo A-I levels decreased (-39%, P = 0.0002) and the magnitude of the decrease after alcohol withdrawal was positively related to the duration of hospitalization. Apo B levels increased (+24%, P < 0.005). Among the anthropometric parameters, arm muscle area was significantly higher after alcohol withdrawal. The energy and macronutrient intakes did not significantly change during hospitalization. It is concluded that the modifications of HDL-cholesterol, HDL3-cholesterol, HDL2-cholesterol Apo A-I and Apo B values were induced by alcohol withdrawal in this population of chronic french alcoholics.

Adult↗