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Biomedical subjects

M Bureau

Publications and source records attributed to M Bureau.

At least 19 recordsLinked to original sources
PubMed2001

Electric pulses increase the immunogenicity of an influenza DNA vaccine injected intramuscularly in the mouse.

Vaccination by intramuscular injection of naked DNA is very efficient in the mouse, but immunogenicity of DNA vaccines needs to be improved in man. The aim of our study was to determine in BALB/c mice if suitable electric pulses delivered to the muscle after DNA injection--a procedure called electrotransfer--could improve the immunogenicity of suboptimal doses of a DNA vaccine expressing the influenza hemagglutinin protein. The results show a significant enhancement of the cellular and antibody responses following electrotransfer for the 1- and 10-microg DNA doses, respectively, but no effect on a lower dose. At the 10-microg dose, the IgG and hemagglutination inhibition mean titres were increased 25-fold and the inter-individual variability was markedly reduced.

Animals↗
PubMed2001

Risks of induction of labour in uncomplicated term pregnancies.

Our objective was to evaluate the risks of maternal and perinatal morbidity associated with induction of labour in uncomplicated term pregnancies. We conducted a retrospective cohort study including 7,430 women, not referred from another institution, with a single baby in vertex presentation, and delivering between 38 and 40 weeks of pregnancy. Among these women, 3,546 were excluded for prelabour pregnancy complications. Relative risks (RR), adjusted for parity, were computed to compare 3,353 women who went into labour spontaneously with 531 women whose labour was induced. Induction of labour was found to be associated with a higher risk of caesarean section [RR = 2.4, 95% CI 1.8, 3.4]. Use of non-epidural [RR = 1.5, 95% CI 1.2, 1.8] and of epidural analgesia [RR = 1.4, 95% CI 1.1, 1.7] was more frequent after labour induction. Resuscitation [RR = 1.2, 95% CI 1.0, 1.5], admission to the intensive care unit [RR = 1.6, 95% CI 1.0, 2.4] and phototherapy [RR = 1.3, 95% CI 1.0, 1.6] were more frequent after induction of labour. Results were similar when controlling simultaneously for parity, maternal age, gestational age, year of delivery, birthweight and the physician in charge of delivery in a logistic regression analysis. The results of this study suggests that induction of labour is associated with a higher risk of caesarean section and of some perinatal adverse outcomes. Induction of labour should be reserved for cases where maternal and perinatal benefits outweigh the risk of these complications.

Adult↗
PubMed2001

[Psychiatric disorders in juvenile myoclonic epilepsy].

Mild personality problems have been described in patients with juvenile myoclonic epilepsy (JME), but clinical practice shows that JME can be diagnosed in patients with more or less severe psychiatric disorders (PD). The presence in JME patients of personality disorders has been described repeatedly, but never quantified. We thus decided to evaluate, using the DSM IV, the current prevalence and types of PD in a large series of consecutive, newly referred patients with JME. Among 170 consecutive JME cases referred to two departments of epileptology (Marseilles and Nice) between 1981 and 1998 (66 males, 104 females; aged 11.7-70; mean+/-SD 32.4+/-10.4 follow-up 12.7+/-10 [0.5-52]), we found 45 patients (26.5p.100) with PD. According to the DSM IV, they could be classified as severe mental retardation (main diagnosis) (one case); pervasive developmental disorders (2 cases); tic disorder (1 case); enuresis (1 case); psychotic disorders (5 cases, including schizophrenia paranoid type (1 case), disorganized type (1 case), delusional disorder (1 case), unspecified (2 cases)); depressive disorders (3 cases); generalized anxiety (6 cases); anorexia nervosa (2 cases); personality disorders (24 cases, including borderline personality (11 cases), dependent personality (5 cases), histrionic personality (2 cases), obsessive-compulsive personality (1 case), not specified (5 cases)). Sudden unexplained death occurred in 2 cases (borderline personality and pervasive developmental disorder not otherwise specified, respectively) and death due to pneumonia in 1 cases (anorexia). Although uncommonly severe cases of JME may have been selected in our referral centers, it appears that JME may be associated with PD. Comparatively mild personality disorders are the most common finding, and may be part of the clinical picture to some extent, while severe PD are less common, and probably coincidental. The presence of PD does not exclude the diagnosis of JME, and PD may represent a further challenge in the comprehensive care of these patients.

Adolescent↗
PubMed2000

Influence of oviductal cells and conditioned medium on porcine gametes.

The aim of this study was to optimise porcine in vitro fertilisation (IVF) with cryopreserved semen with the exploitation of the oviduct secretion. The oocytes were cultured in NCSU37 supplemented with db-cAMP (1 mM), porcine follicular fluid (pFF; 10%), cysteine (0.1 mg/ml) and beta-mercaptoethanol (25 microM) for 44 h (the first 20 h with 10 IU/ml hCG and PMSG). The oviductal epithelial cells (OEC) were cultured in TCM-199 medium (with 10% FCS, 0.2 mM pyruvate and 50 microg/ml gentamicin) for 48 h. To determine the effects of OEC and conditioned medium, oocytes were separated into five groups for the last 3 h of maturation and placed in: fresh maturation medium (controls), OEC-cNCSU with OEC in the maturation medium for 24 h; OEC-fNUSU with fresh OEC in maturation medium; cTCM with TCM-199 conditioned with OEC for 48 h; or fTCM with fresh TCM-199. Results indicate that OEC-cNCSU and OEC-fNCSU increase the number of oocytes reaching the two pronucleus (2PN) stage (p < 0.01) and decrease the polyspermy rate (p < 0.01) compared with controls. The rates are significantly lower than controls when cTCM and fTCM were used (p < 0.01). As regards blastocyst rates, an increase was observed in the OEC-cNCSU and cTCM groups (p < 0.05). For the second experiment, spermatozoa were incubated with OEC in IVF medium (mTBM medium supplemented with 0.1% BSA) without caffeine for 4 h prior to IVF. Results indicate that sperm treatment with OEC increases the 2PN rate (p < 0.01) compared with controls and reduces the polyspermy rate (p < 0.01). In conclusion, our study shows that co-incubation of OEC with both oocytes and sperm before IVF reduces polyspermy rates and improves embryo development.

Animals↗
PubMed1999

Are there generalised spike waves and typical absences in benign rolandic epilepsy?

Generalised 3 Hz spike wave (SW) discharges with or without absences have been described in children with benign epilepsy with centrotemporal spikes (BECTS), leading to speculations about a continuum between childhood absence epilepsy (CAE) and BECTS. We thus decided to evaluate the prevalence of absence seizures (AS) and generalised 3 Hz SW in patients with BECTS. All patients with BECTS first referred since 1986 have been identified prospectively. Their medical and electroencephalograph (EEG) records were analysed retrospectively, in the search for AS and generalised SW discharges. Over a period of 11 years, we found typical rolandic spikes in 66 newly referred patients; 64 had seizures typical for the condition (18 female, 46 male), two were asymptomatic and were not further analysed. All had routine waking EEG recordings, and 49 children (76%) had at least one sleep EEG. AS or classical generalised 3 Hz SW were never recorded from history or EEG data, respectively. However, 17 patients had some diffuse SW discharges, lasting 1-5 s, which appeared as grossly symmetrical in only seven children, with a clearly asymmetrical aspect in the others. Among these seven patients, the discharges were only seen on awakening in one, both during waking and nREM sleep stage I or II in one and only during nREM sleep stage I or II in five. They were apparently subclinical in all. We thus found neither AS nor classical 3 Hz SW discharges among 64 consecutive patients with BECTS. Brief bursts of bilateral abnormalities occur in about 25% of the cases, mostly with sleepiness. Such findings do not substantiate the existence of a continuum between CAE and BECTS.

Child↗
PubMed1999

Heterogeneous distribution of polyamines in temporal lobe epilepsy.

Polyamine contents were determined in human temporal lobe epilepsy. In the seven patients studied, stereoelectroencephalography (SEEG) located the epileptogenic focus in Ammon's horn and neuropathological findings were limited to hippocampal gliosis and sclerosis. Each polyamine exhibited a specific regional distribution. The most important variations were observed for spermidine and spermine while putrescine levels varied less. The regional variation was predominant in middle > posterior > anterior parts of the temporal lobe. Spermine contents and the spermidine/spermine (SPD/SPM) index varied especially in the middle and posterior parts of the hippocampus. Metabolic SPD/SPM index and spermidine levels were found to be drastically increased in almost all limbic parts when compared to neocortical regions. The opposite was observed for spermine. The heterogeneous distribution of polyamines was compared to abnormal electrical activities recorded by SEEG: SPD/SPM index and spermidine levels were sharply increased in seizure onset areas and high levels of spermine were detected in temporal cortex propagation areas. The presently reported heterogeneity of polyamine contents might contribute to modulate differentially the local control of excitability in human temporal epilepsy.

Adult↗
PubMed1999

Radiosurgery for trigeminal neuralgia and epilepsy.

The role of Gamma Knife surgery in the field of functional surgery recently has evolved dramatically. For treatment of trigeminal neuralgia, Gamma Knife surgery is the least invasive procedure, with a low rate of hypesthesia. If a rate of complete relief similar to that of other surgical techniques could be achieved, this approach will become one of the main techniques used to treat the disease initially. The authors present their experience with a group of 16 patients with mesial temporal lobe epilepsy who have been treated successfully (15 completely seizure-free and 1 with rare, nondisabling seizures) without significant complication. After additional follow-up to demonstrate the absence of long-term consequences, this fascinating new approach could change epilepsy surgery practice dramatically.

Adult↗
PubMed1998

Epilepsies and video games: results of a multicentric study.

OBJECTIVES: The purpose of this study was to research whether or not video games may induce paroxysmal discharges (PD) in different groups of patients. METHODS: One hundred and fifteen subjects from 5 different French laboratories were studied: 33 had seizures exclusively under visual stimuli, 42 had both photogenic seizures and spontaneous seizures occuring independently, and 40 had non-photogenic seizures. The same protocol which included one TV sequence, 3 sequences of video games selected on particular criteria (pattern, luminosity and nature of the scene), were presented at different distances from the TV screen at 50 and 100 Hz. RESULTS: Among the factors provoking paroxysmal discharges (PD) some seem crucial: the frequency of the TV screen (the 100 Hz screen was significantly safer than 50 Hz), the distance from the screen (1 m safer than 50 cm), and, particularly for the 50 Hz screen, the specific pattern of the images and the act of playing. CONCLUSIONS: Video games are ineffective for subjects known as having a non-photosensitive epilepsy, but may induce PD on subjects known as photosensitive even when intermittent light stimulation (ILS) is not effective. These results based on a different approach than in other publications confirm data which were suggested by the literature, and suggest that 100 Hz TV screens should be recommended to patients with TV-induced attacks.

Adolescent↗
PubMed1998

Multilobar polymicrogyria, intractable drop attack seizures, and sleep-related electrical status epilepticus.

BACKGROUND AND OBJECTIVE: Patients with cortical malformations often have intractable seizures and are candidates for epilepsy surgery. Within an unselected series of patients with various forms of cortical malformation, nine patients with multilobar polymicrogyria had electrical status epilepticus during sleep (ESES) accompanied by infrequent focal motor seizures. Eight patients also had intractable atonic drop attack seizures. Because ESES usually is accompanied by a good long-term seizure prognosis, the objective of this study was to examine ESES outcome among patients with a structural lesion that is usually highly epileptogenic and has a low seizure remission trend. METHODS: The nine patients had follow-up periods lasting 4 to 19 years. All underwent brain MRI, serial sleep EEG recordings, and cognitive testing during and after ESES. RESULTS: ESES and drop attack seizures appeared between the ages of 2 and 5 years (mean, 4 years) and ceased between the ages of 5 and 12 years (mean, 8 years). At the last visit patients were 8 to 23 years of age (mean, 14.5 years) and were either seizure free or had very infrequent focal motor seizures during sleep. Three patients were free from antiepileptic drugs. In no patient was definite cognitive deterioration apparent after ESES in comparison with earlier evaluations. CONCLUSIONS: Age-related secondary bilateral synchrony underlying ESES may be facilitated in multilobar polymicrogyria. The good seizure outcome contrasts with that usually found in the presence of cortical malformations. For children with polymicrogyria and drop attack seizures, surgical treatment of the epilepsy should be considered cautiously, and sleep EEG recordings should be performed systematically.

Age of Onset↗
PubMed1997

Prognostic factors for childhood and juvenile absence epilepsies.

To assess prognostic factors for absence epilepsy (AE), we analyzed data from 80 patients treated for childhood AE (CAE; n = 53) or juvenile AE (JAE; n = 27) in our epilepsy clinic between 1985 and 1992. All patients were classified according to the International Classification of Epileptic Syndromes which was proposed by the International League against Epilepsy in 1989. Patients were separated into two groups based on the course of disease under adequate treatment: Complete response group (CRG): disappearance of absence seizures (AS) or generalized tonic-clonic seizures (GTCS). Poor response group (PRG): persistence of AS and/or GTCS. Approximately 40% of both CAE and JAE patients had poor response. One parameter was associated with poor prognosis in CAE patients, the presence of polyspikes or polyspikes and waves during sleep. No statistical correlation was made for JAE patients. GTCS were frequent in JAE and GTCS occurrence in CAE patients was associated significantly with age at onset after 8 (p < 0.05). The fact that social and educational performance was poorer in the PRG of both types of AE underlines the importance of therapeutic response in patient rehabilitation.

Adolescent↗
PubMed1997

[Intervention of GABAergic neurotransmission in partial epilepsies].

The gamma-aminobutyric acid (GABA) is one of the most important inhibitory transmitter in the CNS. When GABA is released in the synaptic cleft, it can act on two types of receptors, type A (GABAA-R) and type B. The GABAA-R is an ionotropic receptor whose subunits form a chloride channel. It contains specific binding sites at least for GABA, benzodiazepines, picrotoxin, barbiturates, anesthetic steroids, divalent cations such as Zn2+ and other compounds. Neurotransmitters and neuropeptides that regulate intracellular second messengers may modulate the responses of GABAA-R in the post-synaptic membrane and thus affect the synaptic plasticity. While consensus sites for several kinases are present on many subunit-subtypes, the functional consequences of these phosphorylations are unclear. However, the maintenance of normal GABA currents required the activity of a unique kinase specific for the GABAA-R. This intracellular regulation site might be involved in synaptic plasticity and considered as a site of vulnerability for epileptogenesis. The generation of epileptic discharge, synchronized burst firing and interictal spikes, can be subsequent to the alteration of GABAA-R function. A consequence of GABAergic disinhibition is the formation of new polysynaptic pathways leading to a network of neurons that were previously not connected. Cell loss and plasticity are currently observed in most patients with temporal lobe epilepsy. CA1 pyramidal cells are missing and mossy fibers of dentate granule cells project back through the granule cell layer to form recurrent terminals on granule cell dendrites. This mossy fiber sprouting leads to the destruction of most dentate hilar somatostatine interneurons. Nevertheless, local circuit neurons containing glutamic acid decarboxylase survive in this layer and in all regions of the sclerotic hippocampus. A decrease of the GABA release has been proposed as a basis for disinhibition temporal-lobe epilepsy is partially characterized by a loss of glutamate-stimulated GABA release that is secondary to a reduction in the number of GABA transporters. A molecular reorganization of GABAA-R subunits has been suggested in the kindling model of temporal lobe epilepsy because the zinc released from abberantly sprouted mossy fiber terminals is responsible for a collapse of augmented inhibition by GABA. These results support the concept of a loss of inhibition in chronic epilepsy models and probably in human epilepsies.

Animals↗
PubMed1996

Cortical myoclonus in Angelman syndrome.

Angelman syndrome (AS) results from lack of genetic contribution from maternal chromosome 15q11-13. This region encompasses three GABAA receptor subunit genes (beta3, alpha5, and gamma3). The characteristic phenotype of AS is severe mental retardation, ataxic gait, tremulousness, and jerky movements. We studied the movement disorder in 11 AS patients, aged 3 to 28 years. Two patients had paternal uniparental disomy for chromosome 15, 8 had a >3 Mb deletion, and 1 had a microdeletion involving loci D15S10, D15S113, and GABRB3. All patients exhibited quasicontinuous rhythmic myoclonus mainly involving hands and face, accompanied by rhythmic 5- to 10-Hz electroencephalographic (EEG) activity. Electromyographic bursts lasted 35 +/- 13 msec and had a frequency of 11 +/- 2.4 Hz. Burst-locked EEG averaging in 5 patients, generated a premyoclonus transient preceding the burst by 19 +/- 5 msec. A cortical spread pattern of myoclonic cortical activity was observed. Seven patients also demonstrated myoclonic seizures. No giant somatosensory evoked potentials or C-reflex were observed. The silent period following motor evoked potentials was shortened by 70%, indicating motor cortex hyperexcitability. Treatment with piracetam in 5 patients significantly improved myoclonus. We conclude that spontaneous, rhythmic, fast-bursting cortical myoclonus is a prominent feature of AS.

Adolescent↗
PubMed1995

[Misleading aspects of the standard electroencephalogram in juvenile myoclonic epilepsy: a retrospective study of 56 consecutive cases].

Atypical clinical and/or EEG presentation may complicate the diagnosis of juvenile myoclonic epilepsy (JME). To assess the sensitivity of a standard EEG recording, we retrospectively evaluated the EEG performed at their first referral in 56 consecutive JME patients first seen between 1986 and 1992 (26 M, 30 F, aged 12-53, mean 24.4, with onset of JME at age 10-33, mean 14.3). The diagnosis had been made in none of these patients prior to referral, and was often confirmed only during follow-up. A 20-minute standard EEG was recorded, including hyperventilation (HV) and intermittent light stimulation (ILS). This EEG was normal in 15 cases (27%), showing aspecific or misleading changes in 11 cases (20%) and typical changes in only 30 cases (54%). The baseline EEG was normal in 25 (45%), atypical in 11 (20%), and typical for JME in only 20 (35%). HV and ILS yielded 37 and 39 normal, 10 and 7 aspecific and 9 and 10 specific findings, respectively. A single standard EEG without activation may thus be inconclusive or misleading for the diagnosis of JME in more than 50% of newly referred patients.

Adolescent↗
PubMed1995

Thiamine deficiency in cultured neuroblastoma cells: effect on mitochondrial function and peripheral benzodiazepine receptors.

When neuroblastoma cells were transferred to a medium of low (6 nM) thiamine concentration, a 16-fold decrease in total intracellular thiamine content occurred within 8 days. Respiration and ATP levels were only slightly affected, but addition of a thiamine transport inhibitor (amprolium) decreased ATP content and increased lactate production. Oxygen consumption became low and insensitive to oligomycin and uncouplers. At least 25% of mitochondria were swollen and electron translucent. Cell mortality increased to 75% within 5 days. [3H]PK 11195, a specific ligand of peripheral benzodiazepine receptors (located in the outer mitochondrial membrane) binds to the cells with high affinity (KD = 1.4 +/- 0.2 nM). Thiamine deficiency leads to an increase in both Bmax and KD. Changes in binding parameters for peripheral benzodiazepine receptors may be related to structural or permeability changes in mitochondrial outer membranes. In addition to the high-affinity (nanomolar range) binding site for peripheral benzodiazepine ligands, there is a low-affinity (micromolar range) saturable binding for PK 11195. At micromolar concentrations, peripheral benzodiazepines inhibit thiamine uptake by the cells. Altogether, our results suggest that impairment of oxidative metabolism, followed by mitochondrial swelling and disorganization of cristae, is the main cause of cell mortality in severely thiamine-deficient neuroblastoma cells.

Adenosine Triphosphate↗
PubMed1995

Astroglial cells express large amounts of GABAA receptor proteins in mature brain.

GABAA receptors were characterized in cellular fractions isolated from adult bovine brain. The fraction enriched in cortical astrocytes is very rich in high-affinity binding sites for [3H]flunitrazepam and other "central-type" benzodiazepine ligands. The amount of specific [3H]flunitrazepam binding was more than five times higher in the glial fraction than in synaptosomal and perikaryal fractions. [3H]Flunitrazepam was displaced by low concentrations of clonazepam and other specific ligands for central GABAA receptors. Specific binding sites for GABA, flunitrazepam, barbiturates, and picrotoxin-like convulsants were characterized. Allosteric interactions between the different sites were typical of central-type GABAA receptors. The presence of alpha-subunit(s), as revealed by [3H]flunitrazepam photoaffinity labeling, was demonstrated in all brain fractions at molecular mas 51-53 kDa. Photoaffinity labeling was highest in the glial fraction. However, in primary cultured astrocytes from neonate rat cortex, no photoaffinity labeling was detected. Information obtained from astrocytes in culture should thus be taken with caution when extrapolated to differentiated astroglial cells. Our results actually show that, in mature brain, most of the fully pharmacologically active GABAA receptors are extrasynaptic and expressed in astroglia.

Aging↗
PubMed1995

Idiopathic photosensitive occipital lobe epilepsy.

We studied 10 neurologically normal patients (8 females, 2 males) aged 8-30 years (mean 17 years) who had recurrent episodes if visually induced occipital seizures. Television and computer screens were the main triggers. Seizure onset occurred between the ages of 5 and 17 years (mean 11 years). All seizures were stimulus related and began with elementary visual symptoms, followed in most patients by a slow clustering of cephalic pain, epigastric discomfort, and vomiting, with either normal of only mildly impaired responsiveness. EEG features included normal background activity, occipital spikes and waves, and a photoparoxysmal response which could be occipital, generalized, or both. Four patients also showed spontaneous generalized epileptiform abnormalities, and 3 had rolandic spikes. An Oz electrode was critical in identifying epileptiform activity in some patients. Complete seizure control was achieved in most patients with monotherapy, although occasional stimulus-related seizures occurred in 3 patients who showed a wider range of photosensitivity. These patients have an idiopathic localization-related epilepsy with age-related onset and specific mode of precipitation. Although this type of epilepsy has been reported previously, it has remained underrecognized, probably because it is difficult to differentiate clinically from migraine or from nonreflex childhood idiopathic occipital epilepsy.

Adolescent↗