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Biomedical subjects

F Brion

Publications and source records attributed to F Brion.

At least 37 records · Page 2Linked to original sources
PubMed2000

A vortex-bowl disk atomizer system for the production of alginate beads in a 1500-liter fermentor.

Using a model system, a concept for the immobilization of microbial cultures within alginate beads directly in a 1500-L fermentor with a height to diameter ratio of 1.85 is described. The system is comprised of a 60-cm diameter bowl fixed to the top of an agitation shaft, where calcium-ion-rich media is continuously recirculated from the bulk solution to the bowl. The rotation of the shaft and bowl creates a climbing film (vortex) of solution. An atomizing disk centrally recessed within the bowl sprays an alginate solution into the climbing film where the droplets harden into beads. The effect of heat treatment on the alginate solution on resulting bead properties was examined. The sterilization operation did not appear to have a major effect on the alginate bead mechanical properties of firmness and elasticity which was much more a function of alginate concentration. Beads of various sizes were produced by the unit. The system was characterized by the dimensionless numbers Reomega = (omega x rho x D(2))/mu and ReQ = (Q x rho)/(mu x D). At Reomega and ReQ values less than 500 and 0.15, respectively, the mechanism was direct drop. Parent droplets followed by satellite droplets were observed. When either the flow rate or speed was increased, filaments formed predominantly, which was unwanted in this system because filament breakdown into smaller droplets does not occur due to the proximity of the disk to the climbing film in the bowl. This system could be applied to the immobilization of microorganisms, as well as plant or animal cell cultures, and for other sizes or fermentors. The overflow from the bowl carries the gellified beads into the bulk solution where immobilized cells could act upon the fermentation media.

Alginates↗
PubMed2000

Quantitative high-performance liquid chromatographic determination of acrolein in plasma after derivatization with Luminarin 3.

A rapid, sensitive and specific high-performance liquid chromatographic method for the quantification of acrolein (1), one of the toxic metabolites of oxazaphosphorine alkylating agents (cyclophosphamide and ifosfamide) was developed. Condensation of acrolein with Luminarin 3 afforded a fluorescent derivative that could be specifically detected and quantified. Chromatographic conditions involved a C18 RP column Uptisphere and a gradient elution system to optimize resolution and time analysis. The method showed high sensitivity with a limit of detection of 100 pmol/ml and a limit of quantification of 300 pmol/ml. This technique is particularly suitable for pharmacokinetic studies on plasma of oxazaphosphorine-receiving patients.

Acrolein↗
PubMed2000

Two-step purification method of vitellogenin from three teleost fish species: rainbow trout (Oncorhynchus mykiss), gudgeon (Gobio gobio) and chub (Leuciscus cephalus).

A two-step purification protocol was developed to purify rainbow trout (Oncorhynchus mykiss) vitellogenin (Vtg) and was successfully applied to Vtg of chub (Leuciscus cephalus) and gudgeon (Gobio gobio). Capture and intermediate purification were performed by anion-exchange chromatography on a Resource Q column and a polishing step was performed by gel permeation chromatography on Superdex 200 column. This method is a rapid two-step purification procedure that gave a pure solution of Vtg as assessed by silver staining electrophoresis and immunochemical characterisation.

Animals↗
PubMed2000

[Pediatric drug preparations in French hospitals. Pediatric Group of the French Clinical Pharmacy Society].

AIMS: Drug formulations that are specifically intended for pediatric use have not been widely developed in France and do not adequately meet therapeutic needs, particularly as regards hospital requirements. A multicenter study was therefore carried out to evaluate the situation. MATERIALS AND METHODS: A questionnaire was sent out in June 1998 to all French university hospital pharmacies and also to those public and private hospitals known to be involved in pediatric care. Of the 78 questionnaires mailed, 63 answers were received. The information requested concerned all the drug formulations prepared in 1997. RESULTS: Ten out of the 63 hospitals that replied stated that the questionnaire was not relevant in their particular case. Fifty-three answers were therefore evaluated, i.e., corresponding to data from 35 university hospitals, 15 public general hospitals, and three private hospitals. For 7,022 pediatric beds, 1,155,544 units were prepared consisting of 968,520 capsules prepared from 220 active substances, 33,493 liquid preparations for oral intake, 87,592 parenteral nutrition bags, 48,225 injectable antibiotic drugs, 10,663 injectable anticancer agents, and 7,051 miscellaneous sterile preparations. The most frequently prescribed active substances were, in decreasing order of importance, as follows: diphemanil, captopril, fludrocortisone, ranitidine, spironolactone, and ursodesoxycholic acid. A marked heterogeneity was displayed in galenic forms and drug dosages. CONCLUSION: In conclusion, this study has shown the most commonly prescribed drugs and the most frequently prepared dosages for pediatric use. Drug manufacturing companies may find it an useful source of information on the limited pediatric market; it may also encourage pediatricians to homogenize and optimize their therapeutic strategies, and pharmacists to establish specific quality-control procedures. The authors recommend that national guidelines be set up, and it is suggested that the health authorities could participate in organizing the means whereby drugs for pediatric use are made more readily available.

Chemistry, Pharmaceutical↗
PubMed2000

Postoperative death and malpractice suits: is autopsy useful?

This report demonstrates the extremely high yield of autopsies performed in the case of postoperative death with suspicion of malpractice. They frequently identified undetected complications. They could also suggest faulty or negligent practice that would otherwise go unrecognized. This report supports the widespread use of autopsies to investigate perioperative death.

Adult↗
PubMed2000

Neuronal apoptosis in human immunodeficiency virus infection.

Neuronal apoptosis has been shown to occur in HIV infection by a number of in vivo and in vitro studies, however, the cause of neuronal damage in AIDS is still unclear and its relationships with the cognitive disorders characteristic of HIV dementia remain a matter of debate. In this review, based on our experience, we analyse the techniques used to identify neuronal apoptosis on post-mortem AIDS brains and describe the relationships of neuronal apoptosis with the stage of disease, a history of HIV-dementia, the degree of productive HIV infection, microglial activation, blood-brain barrier involvement and axonal damage. We conclude that the severity of neuronal apoptosis in the cerebral cortex correlates with the presence of cerebral atrophy, but not with the cognitive disorders. There is no global quantitative correlation between neuronal apoptosis and HIV encephalitis, microglial activation or axonal damage. However we found some topographical correlation between these changes. We conclude that neuronal apoptosis and consequent neuronal loss, in HIV infected patients, are probably not related to a single cause. It seems likely that microglial activation, directly or indirectly related to HIV infection of the CNS, plays a major role in its causation possibly through the mediation of oxidative stress. Axonal damage, either secondary to microglial activation, or to the intervention of systemic factors may also contribute to neuronal apoptosis.

AIDS Dementia Complex↗
PubMed2000

[Efficacity of antiseptic products].

Chemical antiseptics are used in specified conditions. This work studied the actual standards to evaluate the activity of antiseptics. Afterward, the main indications of antiseptics are summarized.

Anti-Bacterial Agents↗
PubMed1999

Stability and compatibility of an aerosol mixture including N-acetylcysteine, netilmicin and betamethasone.

The physicochemical stability and the compatibility between N-acetylcysteine (1 g/5 ml), betamethasone (4 mg/1 ml) and netilmicin (100 mg/1 ml) were studied at room temperature (25+/-2 degrees C) over 1 h. During this study, drug concentrations were measured using three separate HPLC methods with UV detection at t=0, 5, 10, 20, 30, and 60 min. The pH of the mixture was determined. Degradation products of the drugs were assayed using HPLC. This study demonstrates the stability and compatibility of the mixture over 1 h at room temperature. The pinkish non-remnant coloration observed when pouring N-acetylcysteine into a recipient has no effect on the stability of the drug.

Acetylcysteine↗
PubMed1999

[A process of programmed cell death as a mechanisms of neuronal death in prion diseases].

Neuronal loss is a salient feature of prion diseases; however, its cause and mechanism, particularly its relationship with the accumulation of the pathogenic, protease resistant isoform PrPres of the cellular prion protein PrPc, are still unclear. A number of studies suggest that it could occur through a process of programmed cell death which is consistent with the lack of inflammation in these conditions. In this paper, we review the different techniques used to identify apoptosis of neurons, and analyse the studies demonstrating neuronal apoptosis in prion diseases, either experimentally, in animal or in human. Apoptosis of rat hippocampal neurons, in cultures exposed to a synthetic peptide homologous to the prion protein, has been identified on morphological criteria after staining by a fluorescent marker of DNA and by gel electrophoresis of neuronal DNA. Apoptosis of neurons has also been identified in vivo using in situ end labelling and electron microscopy in scrapie infected mice. In human, apoptotic neurons were identified by in situ end labelling in Creutzfeldt-Jakob Disease and in Fatal Familial Insomnia. Apoptotic neurons were mostly found in damaged regions and their presence and abundance seemed to correlate closely with neuronal loss. Neuronal apoptosis also correlated well with microglial activation as demonstrated by the expression of major histocompatibility complex class II, antigens, and with axonal damage as identified by beta-amyloid protein precursor immunostaining. In contrast, there was no clear correlation between the topography and severity of neuronal apoptosis and the type, topography and abundance of prion protein deposits as demonstrated by immunohistochemistry. Similarly, within the framework of comparable phenotypes, there was no difference in the abundance and distribution of apoptotic neurons according to the aetiology whether sporadic, familial, or iatrogenic, of the disease. The pathogenetic mechanism of neuronal apoptosis remains speculative and several hypothesis have been proposed. The lack of a direct association between neuronal damage and PrPres deposition may support models of neuropathogenesis based on "loss of function" of PrPc, such as withdrawal of defined activation signals inducing programmed cell death, rather than neurotoxicity. It is also possible that PrPres is neurotoxic and the dissociation between neuronal damage and the amount of protein only reflects variations in selective neuronal vulnerability. Finally, neuronal apoptosis might be an indirect consequence of PrPres deposition. PrPres-induced dendritic or axonal damage, perhaps enhanced by consequent microglial activation, might contribute to neuronal apoptosis either due to deafferentation or to retrograde neuronal degeneration.

Animals↗
PubMed1998

Evaluation of a filling system for binary pediatric solutions.

The aim of this study was to assess the use of an automatic filling system (Siframix M31 and M32 system) to prepare pediatric parenteral nutrition. Volumetric accuracy was measured for each siframix system loads cells (< 5% for 5 ml with the Siframix M32 and < 5% for 9 ml with the Siframix M31) with sterile water for injection. The minimal 20 ml of flushing sterile water of the common tubulure of the Siframix M32 (p = 0.211 for 20 ml and p = 0.75 for 500 ml), the use of viscous solutions (70% dextrose) on the Siframix M31 (p = 0.28 for 20 ml and p = 0.12 for 500 ml) and the use of a special tubulure for using E.V.A. Luer-lock bags (p = 0.89 for 20 ml and p = 0.103 for 500 ml) do not modify the accuracy. Changing bags or bottles during the filling operation modify the accuracy (p = 0.004 for 20 ml and p = 0.009 for 500 ml). A flushing operation is necessary to lower the risk of electrolytic pollution for the filling of little bags. The filling speed for each module was also measured (the maximal filling speed was five liters per minute). The Siframix system allows one to prepare pediatric parenteral nutrition bags when volumes are above 4 ml and with adapted source solutions in terms of concentration and conditioning volumes.

Child↗
PubMed1998

[Evaluation of the Humphrey perimetry programs SITA Standard and SITA Fast in normal probands and patients with glaucoma].

PURPOSE: To evaluate the new threshold strategies of the Humphrey Field Analyser, SITA Standard and SITA Fast, in normals and glaucoma patients. METHODS: Fifty healthy volunteers and 50 glaucoma patients were tested twice with three algorithms: Full Threshold, SITA Standard and SITA Fast in two sessions. The second test was taken into account to eliminate learning effect. Glaucoma patients were chosen to cover a large range of deficits. Quantitative analysis of global indexes was performed as well as qualitative comparison of visual fields by a trained optometrist. RESULTS: Compared to Full Threshold, testing time was reduced by 51% in normals and 49% in glaucoma with SITA Standard and by 72% and 69% with SITA Fast, respectively. In glaucoma, mean testing time dropped from 16'01" with Full Threshold to 8'05" with SITA Standard and to 4'55" with SITA Fast. Quantitative comparison showed a high correlation between indexes (MD Full Threshold vs MD SITA Standard: r = 0.98, p < 0.01; PSD Full Threshold vs PSD SITA Standard: r = 0.94, p < 0.01). However SITA Standard and SITA Fast had a tendency to underestimate visual field defects. In glaucomatous subjects, mean MD ameliorated by 1.01 dB with SITA Standard and by 1.71 dB with SITA Fast. Mean PSD ameliorated by 0.04 dB and 0.43 dB, respectively. Qualitative analysis confirmed these last results showing artificial slight or important improvement of visual fields in 21% of the cases with SITA Standard and 30% with SITA Fast, compared to Full Threshold. CONCLUSION: SITA Standard and SITA Fast strategies improve dramatically visual field testing time, by 51% and 72% respectively. However, one should be cautious in comparing results obtained with different algorithms, as these new strategies improve the mean defect and, to a lesser extent, the localized defect.

Adult↗
PubMed1998

[Extra-hippocampal lesions and alteration of didactic knowledge (semantic explicit memory)].

Brain imaging showed extra-hippocampal temporal lesions in two patients with major disturbances of memory for academic knowledge including complete loss of professional knowledge and school learning especially regarding history, but sparing recent episodic memory in both cases and remote episodic memory in one of them. The antero-inferior and/or lateral regions of the temporal lobe could contain critical structures required to evoke and maintain memory of academic knowledge.

Adult↗
PubMed1997

Liquid chromatographic determination using lanthanides as time-resolved luminescence probes for drugs and xenobiotics: advantages and limitations.

Lanthanide sensitized luminescence is a very attractive alternative to UV detection and other luminescence techniques, i.e., fluorescence and phosphorescence, in separation science for the detection of drugs and xenobiotics because of the large Stokes shift, narrow emission bands and long lifetime. Some published applications of HPLC determination with lanthanide (Ln3+) sensitized luminescence detection are reviewed. Advantages and limitations of this technique are discussed. Normal-phase (NP) HPLC is not influenced by the quenching effect of water whereas reversed-phase (RP) HPLC is applicable to more compounds than NP-HPLC. However, pH adjustment and the quenching effect of water on Ln3+ luminescence are the main drawbacks of RP-HPLC. Elution properties and the need for pH adjustment are two arguments for selecting the mode of addition of Ln3+, i.e., pre- or post-column in the HPLC system. Sensitized Ln3+ luminescence detection is a much more specific method of detection than UV or fluorescence detection after HPLC separation but nevertheless, in some cases, does not always exhibit a significant increase in analytical performance when the donor itself is a strong fluorophore. The development of more powerful excitation sources could improve the limit of detection of the Ln3+ sensitized detection technique. This review suggests that it would be useful to obtain predicting factors about the drug to establish whether the latter is suitable to be measured using an HPLC-Ln3+ approach.

Chromatography, High Pressure Liquid↗