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Biomedical subjects

C Ricour

Publications and source records attributed to C Ricour.

At least 199 records · Page 11Linked to original sources

A carbon-13 breath test to characterize glucose absorption and utilization in children.

After the administration of a 5% glucose-water solution that contained tracer amounts of the stable nonradioactive isotope 13C, breath samples were collected from five children with congenital glucose-galactose malabsorption and five with severe small bowel villous atrophy and chronic diarrhea. The 13CO2 breath test curves of the children with the congenital malabsorption and chronic diarrhea were compared with each other and with those from three healthy children and four infants with severe malnutrition but no diarrhea. The breath test curves from the children with glucose-galactose malabsorption and from those with diarrhea were significantly different from those of the other two groups, a finding consistent with impairment of glucose absorption. The [13C]glucose breath test clearly identified the children with severe glucose malabsorption. Further studies are required to determine whether less severe cases of carbohydrate malabsorption also can be identified using the parameters described in our study.

Breath Tests↗

Role of lipid emulsions in cholestasis associated with long-term parenteral nutrition in children.

BACKGROUND: In children who depend on long-term parenteral nutrition (PN), liver disease is a major complication that may lead to end-stage liver failure requiring liver transplantation. METHODS: This retrospective study investigated the influence of lipid emulsions on cholestasis onset in children receiving long-term total parenteral nutrition (TPN) with lipids. Ten children who presented with a total of 23 episodes of cholestasis, associated in 13 cases with thrombocytopenia, were studied. RESULTS: Changes in the lipid delivery preceded these complications in more than half the cases. The temporary decrease in lipid administration led to normalization of bilirubin in 17 episodes. CONCLUSIONS: These data suggest that lipid supply is one of the risk factors for PN-associated cholestasis. The link between cholestasis and the reticuloendothelial system overload needs to be better understood. Prevention of cholestasis might include the decrease in the lipid load. When cholestasis occurs, lipid supply should be temporarily stopped, especially in the case of associated thrombocytopenia.

Adolescent↗

Plasma and erythrocyte essential fatty acids during total parenteral nutrition in infants: effects of a cutaneous supply.

In order to prevent essential fatty acid (EFA) deficiency induced by fat-free total parenteral nutrition (TPN), 10 infants on TPN were rubbed three times daily for 20 days using oenethera oil (80% EFA). Total EFA amount provided cutaneously was 1900 mg/kg/d. Plasma and red blood cells phospholipids were determined on days 1 and 20 in these 10 treated and six untreated infants on TPN and compared with those of normal control infants. On day 1, plasma nonessential FA including 20:3 n-9(p less than 0.01) were increased in both TPN groups while 18:2 n-6 and 18:3 n-3 (p less than 0.001 and p less than 0.01) were decreased. On the 20th day, EFA deficiency had worsened with a decrease in plasma level of 20:4 n-6 (p less than 0.02) and a higher than normal triene/tetraene ratio : 3.4 +/- 1.1 and 2.3 +/- 0.6 vs 0.1 +/- 0.1 (p less than 0.02). As for red blood cells phospholipids, 16:0 was increased and 18:2 n-6 and 20:3 n-6 were decreased (p less than 0.05) on day 1. On day 20, these FA were more abnormal while 20:3 n-9 became significantly increased (p less than 0.05). No difference was observed between the TPN groups at any time. These results show that cutaneous application of large amounts of EFA-rich oil is unable to prevent or cure TPN induced EFA deficiency.

Absorption↗

Hematologic disorders following prolonged use of intravenous fat emulsions in children.

Abnormalities in hematologic parameters, associated with prolonged utilization of intravenous fat emulsion (IVFE), were observed in seven children on long-term cyclic total parenteral nutrition (TPN). All patients were receiving IVFE (Intralipid 20%) 1 to 2 g/kg/24 hr as part of TPN, during 3 to 18 months. Recurrent thrombocytopenia occurred in all seven patients. Platelet lifespan, as measured with 111 Indium was reduced. Sea-blue histiocytes containing granulations and hemophagocytosis were seen on bone marrow smears. Scans taken after injection of autologous erythrocytes labeled with technetium-99 showed bone marrow sequestration of these cells. Taken together, this constellation of hematologic abnormalities suggests that long-term IVFE administration induces hyperactivation of the monocyte-macrophage system.

Adolescent↗

Blood levels of water-soluble vitamins in pediatric patients on total parenteral nutrition using a multiple vitamin preparation.

Although guidelines for the parenteral use of vitamin preparations in pediatric patients have been published, there are very limited data on the efficiency of these preparations and on the exact needs of infants and children on total parenteral nutrition (TPN). We report here an open, prospective, study of the blood levels of water-soluble vitamins in infants and children on TPN before and during supplementation with a new water-soluble multivitamin formula containing per vial unit: B1, 3 mg; B2, 3.6 mg; B6, 4 mg; niacin, 40 mg; pantothenate, 15 mg; ascorbate, 100 mg; biotin, 60 micrograms; folic acid, 400 micrograms; B12, 5 micrograms. Thirteen children, 9 months to 15 yr old, on home TPN for 1.5 months to 7 yr, and 17 hospitalized infants and children, 1 week to 15 yr old, receiving TPN were studied for 2 weeks to 4 months. Daily doses were given according to age: 1/2 vial if less than 18 months; 1 vial if greater than 18 months and less than 10 years; 1.5 vials if greater than 10 years. Assays for B1, B2, biotin, niacin, plasma and red blood cell (RBC) folates were performed by microbiologic methods, B12 was measured by radioimmunoassay. During the study, B1 levels were consistently above the upper limit of the normal range, B2 and B12 remained in the normal range although there was a slight decrease in B12 values. Almost half of the patients had initially low levels of biotin, niacin, and folates. Biotin, after a significant sharp rise during the first month of supplementation returned to normal range. Niacin levels were initially low in infants and rose toward normal values during treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Conventional and nonconventional modes of vancomycin administration to decontaminate the internal surface of catheters colonized with coagulase-negative staphylococci.

Using a quantitative in vitro model simulating clinical conditions, we studied the efficacy of conventional and nonconventional 3-day therapies involving vancomycin for treating the internal surface of catheters colonized with a slime-producing strain of Staphylococcus epidermidis. When infused for 1 hr every 8 hr through the catheter at the daily dose recommended for a 10-kg child (450 mg), vancomycin alone reduced bacterial colonization but failed to sterilize the inserts. Vancomycin was more active in combination with netilmicin (25 mg for 1 hr every 8 hr), rifampin (150 mg for 90 min every 12 hr), or fosfomycin (500 mg for 4 hr every 6 hr), but the catheters were inconsistently decontaminated after 3 days of treatment. Two nonconventional modes of antibiotic administration were tested for their capacity to ensure high levels of vancomycin in the catheter lumen over a prolonged time. Vancomycin infused continuously through the catheter at a daily dose of 450 mg had the same poor sterilizing effect as vancomycin administered intermittently. On the contrary, catheters were totally decontaminated when 2.5 mg of vancomycin in a volume of 0.5 ml were injected twice daily into noninfused catheters, confirming that the antibiotic-lock technique is an approach of great interest to sterilize the internal surface of catheters colonized with staphylococci.

Catheters, Indwelling↗

Energy expenditure and substrate utilization in the course of renutrition of malnourished children.

Energy expenditure (EE) and substrate utilization in the course of renutrition of malnourished children is not well understood in children receiving total parenteral nutrition (TPN). The aim of this study was to evaluate, during protein-glucose renutrition, EE and substrate utilization and the relationship between EE and growth and/or protein metabolism. Seven malnourished children were studied during the first 3 weeks of TPN. Weight-for-height = 81.4 +/- 8.0%, with an initial weight of 4.5 +/- 3.3 kg. Caloric support was progressively increased according to a preestablished protocol. Every 7 days the following were determined: (1) EE at 3 different 3-hour intervals per day using an open circuit indirect calorimetric system, (2) anthropometrically defined fat free mass (FFM), and (3) 24-hour urinary 3-methylhistidine (3-M-His) and protein balance. Compared to initial values, EE increased 13% at day 7 and 36% at day 14. A negative relationship was found between the amount of perfused glucose and lipid utilization (r = -0.82; p less than 0.0001). EE per kilogram of total body FFM changes during renutrition were more than EE changes per kilogram of total body weight. There was a relationship between EE and weight gain (r = 0.62; p less than 0.005) and a positive relationship between EE and protein gain (r = 0.48; p = 0.012) and 3-M-His excretion (r = 0.51; p less than 0.026).(ABSTRACT TRUNCATED AT 250 WORDS)

Body Composition↗

Effect of an elemental vs a complex diet on polyamine metabolism in rat isolated enterocytes.

BACKGROUND: Polyamines play an important role in the proliferation and differentiation of enterocytes. Ornithine decarboxylase (ODC) is the rate-limiting enzyme for polyamine biosynthesis. Elemental diets, providing easily absorbable nutrients such as free amino acids, are used in clinical practice to treat growth failure and malnutrition. They are very different from complex diets normally consumed. Little information is available about the influence of elemental diets on metabolic capacities of enterocytes. This study was undertaken in rats to assess the effects on polyamine metabolism of an elemental diet compared with a complex diet. METHODS: Rats were fed the elemental diet (group ED) or the control diet (group C) for 14 days. The dietary intakes were isocaloric and isonitrogenous in groups C and ED. Villous enterocytes were then isolated and metabolic capacities or enzyme activities were assessed. RESULTS: Both the enterocyte capacity to decarboxylate ornithine through ODC (measured in viable enterocytes) and ODC activity (measured in homogenates) were severely decreased in group ED. The polyamine content in enterocytes, however, was maintained at a similar level in both groups. This coincided with a decrease in the main enzymatic activity responsible for putrescine catabolism (ie, diamine oxidase activity) in group ED. CONCLUSIONS: Although nutrition manipulation was shown to alter polyamine biosynthesis in this study, the polyamine homeostasis was probably maintained, at least in part, through down-regulation of diamine oxidase.

Amine Oxidase (Copper-Containing)↗

Effect of an elemental vs a complex diet on L-citrulline production from L-arginine in rat isolated enterocytes.

BACKGROUND: L-Arginine and L-glutamine are highly metabolized by intestinal cells, leading to various metabolites, including L-citrulline, which is required for optimal growth. Elemental diets, used in clinical practice to treat growth failure and malnutrition, are very different from complex diets normally consumed. The aim of the present study was to assess the effects of an elemental diet compared with a complex diet on L-arginine metabolism in rat isolated enterocytes and its modulation by L-glutamine. METHODS: Rats were fed the elemental diet (group ED) or the control diet (group C) for 14 days. Villus enterocytes then were isolated, and metabolic capacities or enzyme activities were assessed. RESULTS: The incubation of enterocytes isolated from group C with 0.1 mmol/L L-[U-14C]-arginine led to the production of 125 +/- 25 pmol L-citrulline/10(6) cells per 30 minutes. This production showed a twofold increase in the presence of 2 mmol/L L-glutamine. In group ED, L-citrulline synthesis from L-arginine was markedly lower in the absence or in the presence of L-glutamine. This coincided with lower carbamoylphosphate synthase I activity and carbamoylphosphate (CP) content of enterocytes. Other L-arginine and L-glutamine metabolic pathways were not affected. Similar results were obtained when the elemental diet was administered continuously through a gastric catheter or fed by mouth. CONCLUSIONS: L-Glutamine favors the synthesis of L-citrulline from L-arginine in isolated enterocytes, probably via an increase in CP production. Changing the diet composition, from a complex to an elemental diet, results in an alteration of the enterocyte capacity to synthesize L-citrulline from L-arginine, irrespective of the rhythm of delivery.

Animals↗

Insulin secretion and sensitivity in children on cyclic total parenteral nutrition.

BACKGROUND: Some children receiving total parenteral nutrition (TPN) have abnormal glucose tolerance. METHODS: Insulin secretion and sensitivity were studied in 12 patients, aged 5.7 to 19.4 years, receiving cyclic nocturnal TPN. Insulin secretion was measured during an IV glucose tolerance test (IVGTT; 0.5 g/kg) followed by a hyperglycemic clamp (plasma glucose at 10 mmol/L). Insulin sensitivity was assessed by hyperinsulinemic euglycemic clamp (insulin infusion = 1 mU/kg/min). RESULTS: Patients with normal glucose tolerance receiving TPN had an insulin response to IVGTT similar to that of normal children of the same age. Insulin levels of TPN patients were higher than those in healthy young adults during the hyperglycemic clamp. Whole body glucose disposal was greater in younger than in older children (range, 7.1 to 25.2 mg/kg/min), and this inverse correlation with age was statistically significant (p < .01). Two patients with abnormal glucose tolerance showed a decreased capacity to release insulin, whereas insulin sensitivity was unchanged in one of these two patients. Two patients treated with prednisone or octreotide had insulin levels similar to those of normal TPN children. CONCLUSIONS: The insulin response to sustained hyperglycemia was stronger in children with normal glucose tolerance on cyclic TPN. Patients with a limited capacity to release insulin, either constitutional or acquired, may not be able to produce enough insulin in these conditions and develop glucose intolerance during TPN. Insulin sensitivity was not a key factor in the alteration of glucose tolerance.

Adolescent↗