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Biomedical subjects

F Brion

Publications and source records attributed to F Brion.

65 records · Page 4Linked to original sources

Effects of cortisol on adrenal phenylethanolamine-N-methyltransferase: antagonistic effects of vitamin D in hypophysectomized rats fed a vitamin D free diet.

The influence of individual or combined administration of vitamin D and hydrocortisone on adrenal phenyl-N-methyltransferase (PNMT) in hypophysectomized rats deprived of vitamin D for 1 month has been studied, as well as adrenal and urinary epinephrine and norepinephrine. Daily administration of vitamin D for 11 days decreased PNMT activity and increased adrenal norepinephrine, whereas adrenal epinephrine remained unaffected. Epinephrine and norepinephrine urinary excretion increased after four and nine injections of vitamin D from the hypophysectomized rats fed a vitamin D free diet for 1 month. Hydrocortisone treatment produced increases in adrenal PNMT and epinephrine as well as in urinary excretion of both monoamines. The effects of individual administration are neutralized when the two products are injected together.

Adrenal Glands↗

[Microbiological study of surfaces in the hospital environment].

A quantitative bacteriological study was made, in several hospital services, of the number of organisms present on the floors and various surfaces. Two sampling techniques were used in parallel, direct imprint and brushing. The first of these techniques, new and easy to use, is suggested in this study for the regular surveillance of the microbiological cleanliness of floors, as well as for the selection, under the particular individual circumstances, of the best composition of disinfectant.

Bacteria↗

Pharmacokinetics of cefotaxime and desacetylcefotaxime in the newborn.

A study of the pharmacokinetic parameters of cefotaxime (CTX) and desacetylcefotaxime (dCTX) in newborns was conducted; the former is commonly used for neonatal infections. The elimination half life of CTX correlated with gestational age (GA) and postnatal age (PNA). Elimination of dCTX was longer permitting a synergistic or additive effect with CTX against Gram-negative bacteria. CTX is indicated in the treatment of neonatal sepsis because of the increasing resistance of Escherichia coli to ampicillin and its good efficacy against group B streptococcus.

Cefotaxime↗

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↗

Pharmacokinetic modelling of ifosfamide administered by continuous infusion on 5 days at the dose of 6 g/m2.

BACKGROUND: We aimed to create a model for Ifosfamide (IFX) pharmacokinetics for drug monitoring in order to improve protocol dose intensity. MATERIAL AND METHODS: We studied ifosfamide pharmacokinetics in 12 patients aged 8-19 years. Sixteen courses were modelled (6 g/m2, on 5 days). The auto-induction of ifosfamide was taken into account in the model. Ifosfamide measurement was performed on serum samples by gas chromatography with thermo-ionic detection. Two pharmacokinetic models were compared. The following parameters were estimated: volume of distribution (Vd), clearance at the beginning of the induction (CLi), clearance extrapolated to infinity (CLf), clearance at the end of infusion (CL120), a rate constant (Kc) indicating the clearance variation with time and the lag time (Lag) indicating the time elapsed between the start of infusion and the start of induction. The Wilcoxon test was used to investigate possible differences between models. We tested the hypothesis that Boddy's model is an acceptable simplification of Levy's model. RESULTS: Four of six parameters were significantly different between the two models (p = 0.05). The best curve fitting was obtained using the Levy's model which provided the following estimates, Cli = 2.46 +/- 0.94 L.h-1.m-2, CLf = 5.22 +/- 1.02 L.h-1.m-2, Kc = 0.024 +/- 0.014 h-1, Vd = 18.84 +/- 5.04 L and Lag = 4.86 +/- 6.61 h. The most important difference is found for the distribution volume. CONCLUSION: Levy's model is more accurate and takes into account the integration of clearance.

Adolescent↗

Functional outcome of myositis patients: can a low-dose glucocorticoid regimen achieve good functional results?

OBJECTIVE: During the last few years, in an attempt to reduce the side effects of glucocorticoid (GC) therapy, we have been treating polymyositis-dermatomyositis (PM-DM) patients with a lower starting dose of GC than is classically recommended. In order to validate this approach, we performed a functional re-evaluation of these PM-DM patients. METHODS: A comprehensive protocol evaluating muscle strength, muscle function, CK levels, persistence of spontaneous activity on electromyography, disability in daily life activities and degree of dependence was applied in 25 non-cancer-associated biopsy-proven PM-DM patients, 15 of whom had been treated with a high-dose regimen (i.e. > 0.5 mg prednisolone/kg/day) and 10 with a low-dose regimen (i.e. < or = 0.5 mg prednisolone/kg/day). RESULTS: Our results indicate that the functional outcome of PM-DM patients given a low-dose starting regimen of GC does not differ from that observed in patients given higher doses. Interestingly, vertebral fractures were less common in patients treated with lower GC doses. CONCLUSIONS: Although our analysis has certain shortcomings, including the small number of patients investigated and their uncontrolled assignment to a low-dose or a high-dose GC regimen, the results of this retrospective study suggest that a low-dose starting regimen of GC can achieve a good functional outcome in PM-DM patients, with a reduction of treatment-related disability. This approach would be welcome as a step forward should it be validated by a longitudinal study.

Activities of Daily Living↗

Baxa MicroMacrocompounder for parenteral nutrition solutions in a pediatric hospital.

The constant increase of parenteral nutrition (PN) manufacturing in our pediatric hospital led us to look for an automatic filling system. The aim of this study was to evaluate the MicroMacrocompounder (MM23) for compounding pediatric PN solutions. MM23 volumetric accuracy was tested with its different inlets (S, D, V) for volumes of sterile water for injection from 0.2 to 2900 mL. The influence of the solution viscosity and the source solution bottle replacements during the filling operation was also investigated. Manufacturing pediatric PN solutions was eventually assessed. Time to set up the system was 30 minutes. Maximum filling speeds with sterile water for injection were 860, 330, 154 mL/min for Vx, V and D inlets, respectively. Inlet S was not tested for MM23 filling speed. Minimal flush volume of 40 mL of sterile water for injection is necessary to clear the tube of residual ions. Average MM23 volumetric accuracy was < 5% for volumes > or = 0.5 mL for S and D inlets, and for volumes > or = 20 mL for V inlet. The volumetric accuracy was equal to 6.25% for 0.2 mL. In all experiments, volumetric accuracy was < 5%. The accuracy of electrolyte measurements performed on bag samples was less than 5% for 150 (74%) samples, between 5 and 10% for 27 (13%) samples and greater than 10% for 27 (13%) samples. Microbiological analysis showed no positive culture. The average manufacturing times were 56.8 +/- 4.5, 188.2 +/- 7.7 and 447.2 +/- 13.8 seconds for 130, 660 and 1800 mL bags, respectively. The MM23 compounder is suitable for compounding pediatric admixtures with source solutions volumes > or = 0.5 mL. This system has been used daily for five months in our department.

Child↗

[Post-traumatic Korsakoff's syndrome: clinical and anatomical report].

Clinical and anatomical report of a post traumatic amnestic syndrome (Korsakoff's syndrome), associating anterograde amnesia persisting for fifteen years, with temporal disorientation, false recognitions, initially intense transitory confabulation and secondarily bursts of confabulation, intact remote memory and persistence of old learnings. Death after twelve years from mesenteric infarction. Anatomically, post-traumatic sequellae are limited to both cingulate gyri in their anterior part. This cingula involvement is easy to understand if one knows that post-traumatic Korsakoff's syndrome appears after severe cranial traumatisms, with at least three days of coma, and develops constantly, even if transitory, after long duration comas with 20 to 30 days of loss of consciousness. Anatomical explanation depends on the fact that Korsakoff's syndromes from various etiologies need, to be produced, a bilateral damage of the limbic circuit and that severe head traumatisms, when dying early in the evolution without possibility of a neuro-psychological investigation, have always a destruction of corpus callosum or cingulate gyri or both, resulting from crushing of these structures by the edge of the faulx cerebri. Consistent with these constatations, it is logical that a Korsakoff's syndrome develops after severe head traumas with bilateral lesions of the limbic circuit and especially of the cingulate gyri. But anatomical evidence remains rare, because early fatal evolution does not permit psychological evaluation and, reversely, long survivals who may die from another pathology would not have brain examination. We prefer the name of "Korsakoff's syndrome" rather than that of "amnesic syndrome" to denominate the anterograd amnesia (amnésie des faits récents) encountered in nutritional disorders due to B1 deficiency in true Korsakoff's disease, but also with other etiologies such as cerebral tumours, vascular cerebral disorders, post-commital anoxia, herpetic encephalopathy, head traumas, all of them developing amnesia for recent events, formerly classified under the title of "korsakowian syndrome" or "mental syndrome of Korsakoff" and more recently under the denomination of "amnesic syndrome". But whatever is the etiology of the memory disorder, the amnesic syndrome remains identical and the advanced small differences, such as euphoria in alcoholics or mood depression in tumours, are often fallacious, so that the only way of differentiation deals with accessory symptoms such as intracranial hypertension in tumours, sudden onset in vascular etiologies or polyneuritis in B1 deficiency. Post-traumatic Korsakoff's syndrome joins with this scheme, for its clinical aspect is so similar to that of nutritional disorders that it might be difficult to reach the exact diagnosis when an alcohol addict develops, after a head trauma, an amnesia which could be the consequence of the trauma but also of a nutritional disorder developed after the accident with inadequate parenteral treatment. Our case, which is the first well documented observation of this disease reported with long clinical survey and final pathological examination, was presented in 1981 at a joint meeting of the French and Dutch neurological societies. It gives the proof of the importance, in limbic circuit, of the cingulate gyri. A comparison is made with four other clinical cases of post traumatic amnestic syndrome with MNR procedures which show, for two of them, cingula lesions explaining the clinical features, for one of them a bilateral lesion of Ammon's homs and for the last one extra-limbic lesions, with destruction of the inferior part of both frontal lobes, associated with a possible deafferentation of the right cingula cortex.

Adult↗

Stability of all-in-one standard formulae for paediatric parenteral nutrition.

The Robert Debré Hospital pharmacy unit ensures an annual manufacturing rate of 20,000 parenteral nutrition bags. Until 1999, these bags consisted in binary admixtures, fat emulsions being administered to the patient via a "Y" connexion on the catheter. Since then, all-in-one standard formulae have been established and are manufactured using a Baxa MM23 automated compounder. The aim of this study was to assess the physico-chemical stability of all-in-one admixtures, in order to ensure patient administration safety (mainly avoiding precipitation risks between the nutrients). Three bags of each standard formula were manufactured in monocompartmental bags. Stability assays consisted in the assessment of the admixture's (1) macroscopic aspect, (2) drop size measurement, (3) zeta potential measurement, (4) pH measurement, and (5) osmolality measurement. Tests were conducted between D0 (manufacturing day) and D10 (10 days after manufacture). All-in-one admixtures manufactured according to the established standard formulae were found to be stable for at least 10 days, provided they are kept away from light and at a temperature of +4 degrees C.

Amino Acids↗

[Selenium and vitamin E in mucoviscidosis].

Selenium and vitamin E are two important components which protect membrane lipids from oxidative damage. Recently an abnormal fatty acid turnover in the membrane phospholipids was found in cystic fibrosis (CF). We studied vitamin E and selenium status in 26 CF children compared to a control group. we measured selenium concentration in plasma and erythrocytes using flameless atomic absorption. The measure of erythrocyte glutathione peroxidase activity allowed a functional assessment of selenium. Total plasma tocopherol concentrations (HPLC) were referred to total lipids. The vitamin E and selenium levels in not yet treated children (n = 6) were very low, with an important decrease in glutathione peroxydase activity. The antioxidative agents deficiency was mild in children with pancreatic enzyme replacement and vitamin E supplementation (n = 20). In the 2 groups, this deficiency was combined and may play a role in CF membrane abnormalities.

Adolescent↗

Dose escalation with pharmacokinetics monitoring in methotrexate chemotherapy of osteosarcoma.

This paper evaluates the influence of pharmacokinetics monitoring of HDMTX in the treatment of localized operable previously untreated high grade osteosarcoma. 44 patients (group 1) received a T10 protocol with dose adapted only to age. 27 other patients (group 2) had a pharmacokinetics monitored dose adaptation of MTX. The pharmacokinetics monitoring leads to higher dosage, higher area under the concentration/time curve and permits higher toxicity to be avoided. The higher dose intensity of MTX gave higher histologic response rate (66% compared to 45%) and higher 5 year disease free survival (92% compare to 76%). HDMTX treatment of osteosarcoma should be dose adapted to indivi-dual pharmacokinetics.

Adolescent↗