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Biomedical subjects

R Chioléro

Publications and source records attributed to R Chioléro.

At least 73 records · Page 4Linked to original sources

Thermogenic and metabolic effects of dopamine in healthy men.

OBJECTIVE: To assess the thermogenic response of dopamine at three different infusion rates and to analyze its effects on various biochemical variables. DESIGN: Randomized sequential experimental treatment bracketed by control periods. PATIENTS: Eight young healthy male volunteers with normal body weight (51 to 89 kg). INTERVENTIONS: Three experimental periods during which dopamine was administered iv in a randomized order at rates of 2.5, 5, or 10 micrograms/kg.min with one preinfusion baseline and two recovery periods in between. MEASUREMENTS AND MAIN RESULTS: A significant (p less than .01) increase in resting energy expenditure was observed in response to the two highest dopamine infusion rates (5 and 10 micrograms/kg.min), corresponding to 6% and 15% median increases, respectively, as compared with preinfusion values. At the lowest dopamine infusion rate, no variation in resting energy expenditure was observed. Dopamine induced a significant (p less than .01) increase in hyperglycemia at all three infusion rates, and, at the highest infusion rate, dopamine induced a significant (p less than .05) increase of plasma free fatty acid concentrations. Insulin plasma concentrations were significantly (p less than .05 to p less than 0.1) increased at the three dopamine infusion rates. CONCLUSIONS: Dopamine infusion produces a dose-dependent thermogenic effect and induces various metabolic actions in man.

Adult↗

Prevention of arrhythmias by flecainide after noncardiac thoracic surgery.

Cardiac arrhythmias are a frequent complication after thoracic operations. The prophylactic value of flecainide administered as a constant-rate, intravenous infusion (0.15 mg/kg/h) after a loading dose (2 mg/kg) was tested in a randomized, placebo-controlled study in 30 patients using Holter monitoring during the first 72 hours after operation. A high incidence of atrial and complex ventricular arrhythmias was observed in the placebo-treated group, with a clear predominance in patients undergoing left thoracotomy. Antiarrhythmic drugs had to be added in 6 patients in the placebo-treated group (n = 16), but in none in the flecainide-treated group (n = 14) (p less than 0.01). The preventive effect of flecainide was observed at serum concentrations in the middle of the therapeutic range (409 ng/mL) without side effects. It is concluded that flecainide administration effectively reduced or prevented cardiac arrhythmias after thoracic operations.

Adult↗

The parasympathetic nervous system and the thermic effect of glucose/insulin infusions in humans.

The thermic effect of glucose/insulin infusions was investigated in seven healthy young men before and during either inhibition (atropine sulphate 10 micrograms/kg bolus; 10 micrograms/kg/h) or stimulation (edrophonium chloride, 10 mg bolus; 0.75 mg/min starting rate) of the parasympathetic nervous system. The thermic effects of glucose/insulin were 6.2% +/- 0.4% and 5.6% +/- 0.7% before atropine and edrophonium, respectively, and increased to 7.1% +/- 0.5% (NS) with atropine and 7.5% +/- 1.2% (P less than .05) with edrophonium. In four subjects atropine or edrophonium was infused before the hyperinsulinemic, euglycemic clamp. A significant increase in resting metabolic rate and plasma norepinephrine concentrations was observed with edrophonium alone. When the thermic effects of glucose/insulin were calculated with respect to the metabolic rates observed during the drug infusions alone, they were 5.9% +/- 1.4% and 3.6% +/- 0.6% (NS) for the clamp + atropine and clamp + edrophonium, respectively. These results demonstrate that the increases in the thermic effect of glucose/insulin infusions observed during inhibition or stimulation of the parasympathetic nervous system were due to atropine or edrophonium increasing the resting metabolic rate rather than increasing the thermic response to glucose-insulin infusions. However, because it has been shown that atropine can decrease the thermic effect of an orally administered meal by approximately 60%, it would appear that the parasympathetic nervous system can influence the thermic effect of food by affecting the rate of digestion, absorption and storage of the ingested nutrients.

Adult↗

Incidence of phlebitis in peripheral parenteral nutrition: effect of the different nutrient solutions.

To determine the influence of peripheral parenteral nutrition (PPN) on the incidence of phlebitis and the effect of simultaneous infusion of lipid emulsion, 68 surgical patients were assigned randomly to 3 nutrition groups: (1) amino-acid 4% solution and dextrose 8% (AA + DX) + Intralipid (IL) 10% in the ratio 1.5:1 (2) AA + DX and IL 20% in the ratio 3:1 (3) AA + DX alone. Group 4 (control group) consisted of 25 patients receiving maintenance solutions and iso-osmotic drugs. No filters were used. The cannulae were studied for 72 hours and the cannula sites were evaluated daily for phlebitis. Mean age of patients was 52.3 +/- 17.7 years, with a similar sex ratio in the 4 groups. One hundred and twenty-five cannulae were studied. At 72 h, the following cumulated phlebitis rates were recorded: 22% in Group 1 (712 mOsm/L), 48% in Group 2 (802.5 mOsm/L), 44% in Group 3 (920 mOsm/L) and 26% in Group 4 (260-314 mOsm/L). The phlebitis incidence was similar in groups 1 and 4 (control) throughout the study. Both Groups 2 and 3 had higher phlebitis rates on days 2 and 3 (II: p < 0.05, III: p < 0.01). It is concluded that PPN with simultaneous IL 10% in the ratio 1.5:1 is no more phlebogenic than the usual maintenance solutions during the first 72 h. This is probably due to the lower osmolality and lower DX and K concentrations of the solution with IL 10%. Intralipid 20% does not have the same protective venous effect. The lower complication rate, the limited need for nursing, and lower costs compared to central parenteral nutrition, make PPN a safe nutrition technique for up to 10 days in patients needing no volume restriction.

Journal Article↗

Effects of dopamine on total oxygen consumption and oxygen delivery in healthy men.

The effect of acute intravenous dopamine (DA) administration at three sequential (but randomized) infusion rates was studied in eight young male volunteers. DA was infused at 2.5, 5, and 10 micrograms.kg-1.min-1. O2 consumption (VO2) and CO2 production (VCO2) were measured continuously by means of a computerized indirect calorimeter (blood system). In response to the 5- and 10-micrograms.kg-1.min-1 DA infusion rates, a significant increase (P less than 0.01) in VO2 corresponding to a 6% (range, 3-10) and 15% (range, 12-23) increase, respectively, of preinfusion values was observed. In contrast, at the low dose (2.5 micrograms.kg-1.min-1), DA induced no significant change in VO2. Cardiac output (Qc) increased significantly after the three DA administration rates [19% (range, 0-42), 34% (range, 17-71), and 25% (range, -3 to +47)] for the doses 2.5, 5, and 10 micrograms.-kg-1.min-1, respectively. The increase in O2 delivery (QO2) outweighed VO2 at all administration rates despite the relative drop in QO2 at the maximal DA administration rate. These results indicate that in humans DA improves net O2 supply to tissues proportionally more than it increases VO2 at all doses used in the present study.

Adult↗

[Supplemented local anesthesia in plastic surgery].

A study of 34 reconstructive or aesthetic operations done with supplemented local anaesthesia (local anaesthesia associated with a premedication of methadone, midazolam and droperidol) is presented. Results of this anaesthesia were good in 88% as judged by the surgeon. The immediate post-operative impression was indifferent to pleasant in 85% of the patients. A few months later on, 72% of this cohort of patients would accept a new operation with the same kind of anaesthesia. Although these results are good, ways of improving the results are discussed.

Adolescent↗

Plasma pituitary hormone levels in severe trauma with or without head injury.

In order to evaluate the effect of head injury in severely traumatized patients on the response of ACTH, GH, PRL, and TSH plasma levels, 36 patients were prospectively studied over 5 consecutive days following injury. They were divided into three groups: Group I, severe isolated head injury (n = 14); Group II, multiple injury combined with severe head injury (n = 12); Group III, multiple injury without head injury (n = 10). No significant trend was observed during the 5 consecutive days. The following changes in plasma levels were observed, compared to normal reference value (median values): ACTH was normal in the three groups; PRL was elevated in Group II and normal in the other groups; GH was elevated in all groups; TSH was elevated in Group III and reduced in Groups I and II. Intergroup comparisons showed significantly lower plasma levels for PRL (p less than 0.05) and TSH (p less than 0.01) in Groups I and II, i.e., head-injured patients, compared to Group III, i.e., traumatized patients without head injury. A relationship was observed between the severity of head injury, as expressed by Glasgow Coma Score, intracranial pressure levels, outcome, and TSH and PRL levels.

Adolescent↗

Thermic effect of food: possible implication of parasympathetic nervous system.

To investigate the effect of the autonomic nervous system on the thermic response to food ingestion, respiratory exchange measurements were performed on seven healthy young men for 1 h and 45 min before and 6 h after ingestion of a mixed meal, approximately 560 kcal, 53% carbohydrate, 30% fat, and 17% protein (control) and under the same conditions during infusion of either propranolol (80 micrograms/kg bolus and 1 microgram.kg-1.min-1), atropine (10 micrograms/kg and 10 micrograms.kg-1.min-1), or atropine plus propranolol. The postabsorptive resting metabolic rates were the same on each occasion and were slightly altered by drug treatment. The thermic responses to the meal were the same with the control and propranolol tests (9.3 +/- 0.9 and 9.2 +/- 0.5%, respectively) and were greater (P less than 0.001) than with atropine 3.6 +/- 0.6% and atropine plus propranolol 3.3 +/- 0.8%. Blockade of the sympathetic nervous system does not decrease the thermic response to food taken orally, whereas muscarinic receptor blockade does. Although some confounding effects of atropine might explain some of this decrease, our results suggest that the parasympathetic nervous system is involved in the thermic effect of food.

Adult↗

Hepatic de novo lipogenesis after liver transplantation.

BACKGROUND: The liver can synthesize fatty acids from carbohydrate (de novo lipogenesis [DNL]). We hypothesized that stimulation of this process may be involved in the development of obesity and dyslipidemia, 2 conditions frequently encountered after liver transplantation. METHODS: Hepatic fractional DNL and glucose metabolism were measured in 2 groups of 5 patients (age 36.8 +/- [SD] 14.9 years, BMI 26.3+/-5.3 kg/M2) 1 to 5 years after liver transplantation and 8 healthy subjects (age 28.1+/-5.3 years, BMI 27.2+/-4.5 kg/M2). Subjects were studied while receiving an isoenergetic nutrition (based on 1.1 x their basal energy expenditure) as hourly oral liquid formula during 10 hours. Their hepatic DNL was measured by infusing 1-13C acetate and measuring tracer incorporation in VLDL-palmitate. Their glucose metabolism was assessed by means of 6,6-2H2 glucose and indirect calorimetry. RESULTS: Two liver transplant recipients and 4 healthy subjects were obese, as defined by a BMI > 27 kg/M2. Fractional hepatic DNL was not different in the 2 groups of subjects: liver transplant recipients 3.1+/-1.7% vs 3.2+/-2.1% in healthy subjects. In both groups, DNL increased in proportion to BMI. When both groups were analyzed together, BMI was positively correlated with DNL (DNL = 0.28 x BMI - 4.28, r2 = .445, p < .05). Whole body glucose turnover was 15.0+/-4.4 micromol/kg per minute in liver transplant recipients and 15.8+/-4.1 micromol/kg per minute in healthy subjects (NS). Net carbohydrate oxidation tended to be lower in liver transplant recipients (8.1+/-2.6 micromol/kg per minute) than in healthy subjects (10.4+/-2.4 micromol/kg per minute; NS). Net nonoxidative glucose disposal (4.0+/-2.7 in liver transplant recipients vs 1.9+/-1.8 in healthy subjects, NS) and energy expenditure (0.065+/-0.01 vs 0.065+/-0.01 kJ/kg per minute) were similar in both groups. CONCLUSIONS: These results indicate that fractional hepatic DNL is not altered by liver transplantation during near continuous nutrition. The disposal of orally administered carbohydrate is also essentially unchanged. This strongly argues against a role of hepatic DNL in the pathogenesis of obesity and dyslipidemia after liver transplantation.

Adult↗