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P Hubert

Publications and source records attributed to P Hubert.

At least 127 records · Page 7Linked to original sources
PubMed1996

Efficacy of cyclosporine A in the treatment of macrophage activation syndrome in juvenile arthritis: report of five cases.

OBJECTIVES: To evaluate the efficacy of cyclosporine A in the treatment of macrophage activation syndrome (MAS) occurring in children with juvenile arthritis. STUDY DESIGN: MAS developed in two boys and three girls with systemic juvenile arthritis (four) and polyarticular juvenile arthritis (one). In three children whose condition was life-threatening, increased parenteral administration of corticosteroids failed to improve their condition; therefore cyclosporine A (2 to 5 mg/kg per day) was added. In two other patients with less severe clinical manifestations, cyclosporine A alone (2 to 8 mg/kg per day) was given. RESULTS: After the introduction of cyclosporine A, rapid improvement was obtained in all patients and apyrexia occurred within 24 to 48 hours. The biologic abnormalities disappeared more slowly (up to 5 weeks for liver enzymes). CONCLUSIONS: These observations underline the usefulness of cyclosporine A in this complication. The use of this drug may circumvent the need for increased doses of corticosteroids in some patients. The mechanism of action of cyclosporine A remains speculative, but these results indicate indirectly that T-helper lymphocytes may play a role in the pathogenesis of MAS.

Antirheumatic Agents↗
PubMed1996

Resolution improvement by use of carboxymethyl-beta-cyclodextrin as chiral additive for the enantiomeric separation of basic drugs by capillary electrophoresis.

Three beta-cyclodextrin derivatives--carboxymethyl-, dimethyl- and hydroxypropyl-beta-cyclodextrin--were tested as chiral selectors for the enantioseparation of seven basic drugs in free solution capillary electrophoresis, using buffers made of 100 mM phosphoric acid adjusted to pH 3.0 with triethanolamine in fused silica capillaries thermostatted at 15 degrees C. The best results with respect to chiral resolution were obtained with carboxymethyl-beta-cyclodextrin (CMCD): the enantiomers of all compounds examined were completely resolved with this beta-cyclodextrin derivative. The influence of the CMCD concentration on the migration times, the apparent electrophoretic mobility difference and the resolution of the drug enantiomers was investigated thoroughly. Particularly impressive resolution values, up to 23.7, were obtained for several compounds in these capillary electrophoretic systems, using CMCD in the 5-15 mM concentration range.

Anesthetics, Local↗
PubMed1995

[Paternity determination using the RFLP method in DNA probes].

By the discovery of restriction fragment length polymorphism and hypervariable minisatellite sequences paternity testings have become possible with almost one hundred percent probability. The procedure is based on the improvement of DNA probes which can recognize the different regions of minisatellites in the whole site of human genome. These sequences are found in noncoding regions of DNA, in the so-called intrones, in areas between genes. The sequence motives have a discriminating power and provide a possibility to distinguish individuals.

Child↗
PubMed1995

Processing of chromogranin B in bovine adrenal medulla. Identification of secretolytin, the endogenous C-terminal fragment of residues 614-626 with antibacterial activity.

Chromogranins constitute a family of acidic soluble proteins widely distributed in endocrine cells and neurons. Chromogranin A, the major soluble component in bovine adrenal medullary secretory granules in chromaffin cells, has been shown to be actively processed to peptide fragments [Metz-Boutigue, M. H., Garcia-Sablone, P., Hogue-Angeletti, R. & Aunis, D. (1993) Eur. J. Biochem. 217, 247-257]. In the present paper, the structural features of the proteolytic degradation mechanism of chromogranin B/secretogranin I have been characterized with regard to the possible function of this protein as a precursor of biologically active peptides. Chromogranin-B-derived fragments present in bovine chromaffin granules were identified by microsequencing after separation by two-dimensional gel electrophoresis or high-performance liquid chromatography. A similar approach was performed to characterize chromogranin-B-derived fragments released into the extracellular space from depolarized bovine cultured chromaffin cells. In chromogranin B, 18 cleavage sites were identified along the protein chain and chromogranin B/secretogranin I fragments were generated by proteolytic attack at both the N-terminus and C-terminus. A major fragment corresponding to residues 614-626 of the C-terminal sequence, was identified in the extracellular space; this peptide was found to share sequence and structural similarities with the lytic domain of cecropins and, as expected from this similarity, to display potent antibacterial properties. Endogenous and synthetic peptides were active on Micrococus luteus, killing bacteria in the micromolar concentration range. The synthetic peptide slows the growth of Bacillus megaterium and was inactive towards Escherichia coli. In addition, the synthetic peptide was unable to induce hemolytic activity. This antibacterial function might be of biological significance in the neuroendocrine system of living organisms. We propose to name this peptide secretolytin.

Adrenal Medulla↗
PubMed1995

HIV-1 glycoprotein gp120 disrupts CD4-p56lck/CD3-T cell receptor interactions and inhibits CD3 signaling.

Using the CD4+ human T cell clone P28, we demonstrated that the HIV-1 glycoprotein gp120 inhibited CD3-induced inositol trisphosphate production, calcium influx and T cell proliferation. Additionally, gp120 was shown to dissociate the tyrosine kinase p56lck from CD4 in CEM cells, with a concommittant inhibition of CD4-linked kinase activity. We have addressed the question whether disruption of CD4/p56lck or CD4/CD3-T cell receptor interactions, or both, could account for the inhibitory effect of gp120 in P28 cells. By comparing the effects of various anti-CD4 monoclonal antibodies (mAb) with those of gp120, we show that gp120 and IOT4a modulate CD4 expression, and decrease CD4-associated p56lck and CD4-linked kinase activity at the plasma membrane. In contrast, OKT4A and OKT4 anti-CD4 mAb have no inhibitory effect. Interestingly, gp120 also inhibits CD3-induced Lck activation and cellular tyrosine phosphorylation, particularly of phosphoinositide-specific phospholipase C-gamma-1. Kinetic experiments reveal that the inhibitory effect of gp120 on CD3-induced tyrosine phosphorylation appears as early as 30 min, but culminate when CD4-p56lck complexes disappear from the cell surface after 4 h. These results suggest that a negative signal is triggered by gp120 that results, after a few hours, in down-modulation of CD4-p56lck complexes and the impairment of CD3 signaling. Supporting this hypothesis, gp120 inhibits CD3-linked kinase activity as shown by the inhibition of the phosphorylation of CD3 chains, leading to the inhibition of subsequent signal transduction.

Antibodies, Monoclonal↗
PubMed1995

Biological effects of encapsulated insulin on transfected Chinese hamster ovary cells.

Oral administration of insulin incorporated into the wall of isobutylcyanoacrylate nanocapsule to diabetic rats induces a long-lasting normalization of their fasting glycaemia. In this study, we examined the biological action of encapsulated insulin on DNA and glycogen syntheses in Chinese hamster ovary cells transfected with the human insulin receptor gene. In the 10(-11) mol/l-10(-9) mol/l concentration range, encapsulated insulin elicited responses comparable to those induced by native insulin: at 10(-9) mol/l, the rates of glycogen and DNA synthesis were enhanced by factors 3 and 2.5, respectively. Encapsulated insulin at 10(-7) mol/l evoked receptor desensitization although it did not induce receptor down-regulation and did not alter receptor recycling for up to 6 h. Chloroquine decreased the action of native insulin on glycogen synthesis, but did not affect the dose-response characteristics of encapsulated insulin. Acid-washing of the cells after 1 h of stimulation decreased maximal insulin responsiveness and provoked a dose response curve for encapsulated insulin similar to that of the native hormone. Direct measurement of effective insulin binding activity showed that encapsulated insulin (at 10(-8) and 10(-7) mol/l) was withdrawn from the incubation medium 5-8 times less efficiently than native insulin. These data are in agreement with previous results showing that the polymeric wall protects encapsulated insulin from degradation. Persistence of intact encapsulated insulin inside and outside the cell may result in modifying signalling events and thus be responsible for the observed cellular desensitization.

Animals↗
PubMed1995

Assessment of neonatal ventilator performances.

OBJECTIVE: To analyze efficiency and reliability of 4 modern neonatal ventilators under difficult test conditions. The ventilators tested were: Babylog 8000 (Dräger Medical), BP 2001 (Bear Medical Systems), Sechrist IV 100 B (Sechrist Industries), Infant Star (Infrasonics INC). MEASUREMENTS AND RESULTS: Gas flow generation was tested by comparison of preset flow values with no resistance in the circuit to flow values obtained during interposition of a resistance in the inspiratory circuit. A decrease in gas flow was observed when interposition of a resistance in the inspiratory circuit increased peak inspiratory pressure to 60 cmH2O (gas flow decreased by 8% to 24% depending on the ventilator tested). The pressure limiting valve and the positive end-expiratory pressure valve were also evaluated in order to test their behaviour under different flow conditions. Flow-dependence of the pressure was noted for all ventilators except Babylog 8000. Assessment of the reliability of pressure monitoring revealed either 'under' or 'over' estimation of peak inspiratory pressure and positive end-expiratory pressure depending on the ventilator tested. CONCLUSION: For the best clinical use of mechanical ventilators, neonatologists should be aware of these limitations. Therefore a regular assessment of ventilator performance and monitoring reliability is recommended.

Equipment Failure↗
PubMed1995

Quantitative analysis of non-steroidal anti-inflammatory drugs by capillary zone electrophoresis.

The potential utility of capillary zone electrophoresis (CZE) for the separation and quantitative determination of some non-steroidal anti-inflammatory drugs (NSAIDs) was investigated. The influence of different parameters on migration times, peak symmetry, efficiency and resolution was studied; these parameters included the nature and concentration of the anionic and cationic components of the separation buffer. A buffer consisting of 75 mM glycine adjusted to pH 9.1 with triethanolamine was found to provide a very efficient and stable electrophoretic system for the CZE analysis of NSAIDs, giving RSD values of about 0.1 and 0.5% for the within-day reproducibility of migration times and peak areas, respectively at a concentration of 25 micrograms ml-1 (n = 5). Response was linear from 2-100 micrograms ml-1 for both sulindac and tiaprofenic acid, for which the LOQ values were 2.8 and 1.9 micrograms ml-1, respectively, using UV detection at 280 nm. Accuracy for each drug was 102-103%.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1995

[Chronic septic granulomatosis revealed by neonatal pulmonary aspergillosis].

BACKGROUND: Pulmonary aspergillosis is now the main cause of death in chronic granulomatous disease (CGD); it may occur before the age of one year and then often reveals CGD. CASE REPORT: A male newborn was referred to hospital at 27 days of age for fever (39 degrees C), hemodynamic failure and biological inflammation syndrome caused by pulmonary infection. Chest CT scan revealed multiple and bilateral intraparenchymatous nodules. An open lung biopsy showed histiocystic granuloma with multinucleated giant cells. Culture of tracheal, bronchoalveolar lavage samples and lung biopsy grew positive for Aspergillus fumigatus. Impaired chemiluminescence production by neutrophils was detected, enabling the diagnosis of CGD. It was later confirmed by the study of neutrophils functions. The child recovered after 12 months of parenteral amphotericin B therapy. CONCLUSION: A febrile multifocal pneumopathy occurring in infancy should lead to consider the possibility of CGD which may be confirmed by the chemiluminescence test.

Aspergillosis↗
PubMed1995

Cerebrospinal fluid penetration of amikacin in children with community-acquired bacterial meningitis.

The penetration of amikacin into the cerebrospinal fluid (CSF) was studied with 16 children (mean age, 1 year and 9 months; range, 4 months to 8 years) with community-acquired bacterial meningitis. Amikacin was given intravenously at a dose of 7.5 mg/kg of body weight twice daily. CSF was collected on day 1, at the expected peak concentration of amikacin in CSF. The mean (standard deviation) concentration of amikacin in CSF was 1.65 (1.6) mg/liter. Concentrations of amikacin in CSF correlated significantly with CSF glucose levels on admission. The mean concentrations of amikacin in CSF were 2.9, 1.1, and 0.20 mg/liter in patients with CSF glucose levels of < 1, 1 to 2, and > 2 mmol/liter, respectively. Thus, amikacin penetrates the blood-brain barrier substantially in children with bacterial meningitis and achieves particularly high concentrations when CSF glucose level is < 1 mmol/liter on admission.

Amikacin↗
PubMed1995

[Therapeutic strategy in newborn infants with multivisceral failure caused by interruption or hypoplasia of the aortic arch].

Left heart obstructive lesions, in particular interrupted aortic arch or severe forms of coarctation with hypoplasia of the aortic arch, are the main cause of cardiac failure in the neonate and are often at the root of multiple organ failure which worsens the prognosis. Based on a retrospective study of 35 neonates admitted between July 1984 and June 1994, the authors attempted to identify the prognostic factors for admission to the intensive care unit and the optimal timing for operation of these patients. All neonates with a ductus-dependent aortic obstructive lesion and severe multiple (at least four) organ failure, were included in the study. There was a high mortality (54%) including firstly 7 patients who died in the three days following admission to the intensive care unit (20%); this was so-called "medical" mortality for which there was no identifiable poor prognostic factor. On the other hand, the surgical mortality (12 out of 28 cases, 43%) was significantly different in neonates operated before recovery from multiple organ failure (72%) and those operated after recovery from multiple organ failure (17%). Based on these results, the authors propose a therapeutic strategy based on prolonged preoperative intensive care until the initial multiple organ failure is reversed rather than early surgery.

Aorta, Thoracic↗
PubMed1995

[Accidents, disasters and crises: contribution of epidemiology in th nuclear field].

The experience of the Chernobyl accident has shown the necessity of being prepared for epidemiological assessment of the death consequences of a nuclear or a radiological accident. We discuss the contribution of epidemiology in such situations, in addition to the existing tools designed to assess or manage radiological risks. From a decisional point of view, three issues are distinguished: the protection of the different population groups against ionizing radiations, the achievement of health care and the communication with the public and media. We discuss the input of epidemiological tools in both perspectives. Epidemiology may also contribute to the analysis of health events that may be observed after an accident, i.e. to assess whether these events are not statistical artifacts, whether they are an effect of the exposure to the ionizing radiations or a non specific consequence of any accident. Finally, epidemiological studies should be carried out to improve our knowledge on ionizing radiations effects with a special consideration given to the dose-effect relationships. Examples of past nuclear accidents are used to discuss these issues. The last part of this paper is focused on different research issues that should be developed for preparing epidemiological plans for nuclear accidents.

Disaster Planning↗
PubMed1994

Knowledge-based system for the automated solid-phase extraction of basic drugs from plasma coupled with their liquid chromatographic determination. Application to the biodetermination of beta-receptor blocking agents.

Techniques for the preparation of biological samples are often based nowadays on solid-phase extraction (SPE). The different SPE steps can be performed automatically on disposable extraction cartridges (DECs) by means of a sample processor. A knowledge-based system was developed to facilitate the development of fully automated methods for the solid-phase extraction of relatively hydrophobic basic drugs from plasma, coupled with their determination by high-performance liquid chromatography (HPLC). The DEC filled with 50 mg of cyanopropyl-bonded silica phase is first conditioned with methanol and buffer solution (pH 7.4). After sample application, the DEC sorbent is washed with the same buffer. The analytes are then desorbed with an appropriate eluent and the eluate is finally diluted with the same buffer as used in the HPLC mobile phase before injection. Under these conditions, only three variables are still to be optimized: the composition and volume of the elution solvent and the volume of buffer to be added to the eluate. On the basis of this general strategy, a decision tree providing information about suggested starting conditions and guidelines for the optimization of the three variables was developed and implemented by use of a hypermedia software. This didactic expert system was evaluated using several beta-receptor blocking agents as model compounds and the operating conditions obtained for the automated SPE of these compounds are presented. A method for the determination of propranolol in plasma using the SPE conditions deduced from the knowledge-based system was validated. The absolute recovery of propranolol is ca. 93% and the limit of detection is 1.3 ng ml-1. The mean within-day and between-day reproducibilities are 2.3 and 3.6%, respectively.

Adrenergic beta-Antagonists↗
PubMed1994

Three new cases of the Schinzel-Giedion syndrome and review of the literature.

Three fetuses with normal chromosomes were found to have uni- or bilateral hydronephrosis during the third trimester of pregnancy. At birth, they presented with coarse face, hypertelorism, and a deep groove under the eyes. Fontanelles and sutures were wide open. Genital abnormalities were present in 2 cases. Skeletal radiographs showed delayed bone maturation, broad and dense ribs, and a wide synchondrosis between the exoccipital and supraoccipital bones. The combination of such findings suggested the diagnosis of Schinzel-Giedion syndrome. Two patients died soon after birth, whereas the third one developed severe mental and motor retardation with seizures and spasticity, and died at 18 months. Schinzel-Giedion syndrome is rare and likely to be inherited as an autosomal recessive trait. So far, 13 well-documented cases have been reported allowing major and minor traits of the syndrome to be distinguished. Since no genetic marker is available, the prenatal diagnosis of Schinzel-Giedion syndrome relies on ultrasound examination, especially detection of renal abnormalities.

Abnormalities, Multiple↗
PubMed1994

Chiral separation of basic drugs by capillary zone electrophoresis with cyclodextrin additives.

The enantiomers of a series of basic drugs were separated in capillary zone electrophoresis (CZE) in phosphate buffers, pH 3, containing beta-cyclodextrin or one of its derivatives as chiral selectors and uncoated fused silica capillaries thermostated at 15 degrees C. The nature of the cationic component of the background electrolyte was found to have a significant influence on achiral resolution and peak symmetry. The best results were obtained with triethanolamine, which was then used to adjust the buffer pH in all further experiments. The effects on chiral resolution of the nature and concentration of cyclodextrin, of the addition of methanol, and of capillary temperature were studied. Maximum resolution was obtained at a particular cyclodextrin concentration for each analyte, depending on the affinity of the analyte for this cyclodextrin. On the basis of the results, the effects of methanol addition and temperature on enantiomeric resolution could be explained and predicted. Numerous chiral separations are presented and suggestions for the rapid optimization of CZE enantioseparations with cyclodextrin additives are given.

Alkalies↗
PubMed1994

Determination of benzodiazepines by micellar electrokinetic chromatography.

A method for the separation and determination of benzodiazepines by micellar electrokinetic chromatography (MEKC) has been developed. Separation buffers consisted of aqueous solutions of glycine and triethanolamine (pH 9.0), containing sodium dodecyl sulfate (SDS) as surfactant and methanol as organic modifier. The effect of the concentration of SDS, methanol, glycine and triethanolamine on migration times and resolution was studied. Ten benzodiazepines were baseline separated at a 25 mM SDS concentration and 20% v/v methanol in a 75 mM glycine-250 mM triethanolamine buffer. Under these conditions, the within-day reproducibilities were 0.3-0.5% for migration times and 1.7-1.9% for peak areas at a concentration of 10 micrograms/mL. The limits of detection and quantification for oxazepam were 0.2 and 0.7 micrograms/mL, respectively, using an injection time of 5 s.

Benzodiazepines↗