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Biomedical subjects

J Roger

Publications and source records attributed to J Roger.

At least 37 records · Page 2Linked to original sources
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↗
PubMed1995

[Myoclonus of focal action and localized hemispheric lesion. A polygraphic and pharmacological study].

Authors report a case of focal action myoclonus due to a localized hemispheric lesion. The woman had cardiac arrest complicated by ischemic stroke involving the left parietal region. Action myoclonus of the inferior right limb was the sole residual complaint, provoked by movement and maintenance of posture. Patient noted that myoclonus was worsened by carbamazepine and vigabatrin. EEG-EMG polygraphic study demonstrated action myoclonus and showed a particular EEG activity consisting in a volley of spikes on the vertex region during the right inferior limb movements. Contralateral movements did not elicit this activity. Pharmacological response to clonazepam, piracetam and alcohol was studied. A marked improvement of myoclonus was obtained with alcohol. Pathophysiology of this exceptional form of cortical action myoclonus is discussed.

Anticonvulsants↗
PubMed1995

Use of annexin V-ferrofluid to enumerate erythrocytes damaged in various pathologies or during storage in vitro.

Recombinant human annexin V was bound covalently to 9 nm maghemite (gamma Fe2O3) nanoparticles, yielding annexin-ferrofluid (AnxFF), and used to separate annexin-bound red blood cells (RBC) in a magnetic field and estimate their percentage in various bloods. Annexin binding in normal human RBC increased proportionately with storage from 8% on day 2 to 42% on day 100. Enhanced AnxFF binding was associated with various pathologies. Thus, normal blood contained 10.7 +/- 5.9% AnxFF binding RBC; bloods with normal sedimentation rates (albeit with some disease necessitating analysis) contained 23.5 +/- 6.2%; those with high sedimentation rates contained 51.5 +/- 12.3%; sickle cell anaemia patients' blood contained 50.0 +/- 9.3%, and bloods from patients with other pathologies (deforming rheumatic disease, cancer necessitating chemotherapy, etc.) contained 58.6 +/- 7.6% AnxFF binding RBC. Enhanced Ca+2-dependent annexin binding reflects a loss of the asymmetric distribution of anionic phospholipids in plasma membranes which may constitute a signal for the destruction of the modified cells by the reticuloendothelial system. Once these preliminary results are confirmed, the determination of the fraction of AnxFF bound erythrocytes, following their magnetic separation, could prove a simple and rapid quality test for example in the context of blood transfusion.

Anemia, Sickle Cell↗
PubMed1994

Blood-brain barrier permeability in rats is altered by exposure to magnetic fields associated with magnetic resonance imaging at 1.5 T.

We have previously reported that exposure of rats to low-field (0.15 T) magnetic resonance imaging (MRI) increases blood-brain barrier (BBB) permeability. However, a number of investigators have failed to observe this effect when high-field MRI (1.5 T or higher) is used. Therefore, we investigated whether or not we would observe changes using our technique at these higher fields. Adult male Sprague-Dawley rats were anaesthetised and then exposed to a 22.5 min imaging or sham procedure. Immediately following exposure, rats were injected with 1 MBq of 153Gd-DTPA intracardially and then immediately re-exposed for an additional 22.5 min. The rats were killed 1h following the second MRI exposure, at which time the brain was resected and 3 ml of venous blood collected. The ratio of radioactivity per gram of brain to radioactivity per milliliter of blood, known as the brain-blood partition coefficient, was determined and used as a measure of BBB permeability. Groups of animals had different exposures. Group 1 (n = 9) was exposed to a clinically relevant MRI procedure. Group 2 (n = 20) was exposed to the same procedure except the rf specific absorption rate (SAR) was reduced to 25% and the animals were positioned 15 cm from imager centre to increase the time-varying magnetic field from 0.4 to 2.8 T/s. For the sham exposures (n = 21), the animals were placed in the imager with the static field ramped down to zero and exposed to a sound recording simulating a MRI examination.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Central analgesic effect of valproate in patients with epilepsy.

Clinical practitioners have often observed in the course of their daily work that the pain thresholds of epileptic patients seem to differ from those of healthy subjects. These patients can suffer from quite severe traumatic lesions without apparently experiencing any pain. Previous studies have shown that the absence of pain is due to treatment, since most antiepileptic drugs also have analgesic effects. In the present study, it was proposed to assess the pain thresholds of 15 epileptic patients (with tonic-clonic seizures generalized at outset) treated with valproate, by measuring the leg flexion nociceptive reflex (or RIII reflex) threshold: the stimulation threshold at which this reflex is triggered is known to be correlated with the pain threshold. The results were compared with 15 control subjects. The nociceptive threshold of the patients with valproate treatment was significantly higher than that of the control population. The nociceptive threshold was also in good correlation with the valproate plasma level. These data are discussed from the point of view of the gaba-ergic system and mechanisms possibly involved.

Adolescent↗
PubMed1993

Epileptic negative myoclonus.

Five patients with partial epilepsy of diverse etiology insidiously developed action-activated jerks. The disorder was limited to one arm in two patients and to the legs in another, and was multifocal in the remaining two. Each jerk was related to an EMG silent period lasting 100 to 400 msec, causing a lapse followed by resumption of posture. Simultaneous EEG-EMG recording showed each postural lapse to be time-locked with a sharp or spike and slow-wave transient over the contralateral sensorimotor cortex, where almost continuous paroxysmal activity occurred. The three patients who were able to cooperate during neurologic evaluation also exhibited motor neglect in the most affected body segment and decreased awareness of the disorder. In three patients, the phenomenon was medically resistant, and in two of them it was continuous and could be defined as epilepsia partialis continua. In the other two, medical treatment induced remission of EEG, motor, and neuropsychological abnormalities. This disabling movement disorder can be classified as "epileptic negative myoclonus" and may result from focal-discharge-related transient disruption of cortical function in the sensorimotor cortex.

Adolescent↗
PubMed1992

Nociceptive threshold in patients with epilepsy.

Clinical practitioners have often observed in the course of their daily work that the pain thresholds of epileptic patients seem to differ from those of healthy subjects. These patients can suffer from quite severe traumatic lesions without apparently experiencing any pain. Since they are usually under treatment for epilepsy, it is difficult to determine whether the absence of pain is due to these patients' epileptic condition or to its treatment, since most antiepileptic drugs also have analgesic effects. In the present study, it was proposed to assess the pain thresholds of 15 epileptic patients (10 with tonic-clonic seizures generalized at outset and 5 with temporal lobe epilepsy), by measuring the leg flexion nociceptive reflex (or RIII reflex) threshold: the stimulation threshold at which this reflex is triggered is known to be correlated with the pain threshold. The nociceptive threshold of the patients with generalized epilepsy was not found to differ from that of the control population, whereas that of the patients with temporal lobe epilepsy was spontaneously high and was not reversed upon injecting naloxone. These data are discussed from the point of view of the pain pathways and mechanisms possibly involved.

Adolescent↗
PubMed1992

Continuous focal spikes during REM sleep in a case of acquired aphasia (Landau-Kleffner syndrome).

We report a girl 3 years and 6 months old with onset of aphasia at age 3 years and 3 months. There was no evidence of brain damage and there were no seizures. The neuropsychological evaluation showed that the girl tended to be right-handed, that aphasia was global and that other higher cortical functions seemed to be preserved. Isolated spikes and spikes-and-wave were recorded during wake over the right temporal region with rare independent contralateral abnormalities. During polysomnography (PSG), the physiological patterns of sleep were preserved and right temporal epileptiform discharges were significantly increased in all sleep stages. Maximal activation was obtained at sleep onset and during rapid eye movement (REM) sleep periods, when focal abnormalities became continuous and spread contralaterally. Repeat PSGs showed that the activation profile retained this particular trait, although subclinical discharges tended to increase during slow wave sleep (SWS). This pattern of subclinical temporal status epilepticus during REM sleep differs from the characteristic activation profile found in the syndrome of continuous spikes-and-waves during SWS. However, this profile was transient and all epileptiform changes disappeared during clinical recovery at 18 months of follow-up.

Anticonvulsants↗
PubMed1992

Interactions between clobazam and standard antiepileptic drugs in patients with epilepsy.

We retrospectively collected plasma level assessments performed in 96 adult patients with epilepsy on stable monotherapy, including 9 patients on clobazam (CLB), 34 on carbamazepine (CBZ), 24 on phenobarbital (PB), 9 on phenytoin (PHT), and 20 on valproate (VPA); these results were compared to those obtained in 54 adult patients on stable bitherapy with the association of CLB with either CBZ (n = 17), PB (n = 17), PHT (n = 5), or VPA (n = 15). Our results show that CLB has no significant effect on the level to dose ratio (LDR) of CBZ, PB, PHT, or VPA. Conversely, CBZ, PB, and PHT significantly decrease the LDR of CLB. CBZ and PHT significantly increase the LDR of N-desmethylclobazam (NCLB), the major metabolite of CLB. A significant increase in the NCLB/CLB ratio was found in CBZ + CLB, PB + CLB, and PHT + CLB bitherapies. These findings are of clinical significance: clobazam is useful as adjunctive treatment in human epilepsy and is often chosen as the benzodiazepine adjunctive drug in chronic resistant epilepsy. Sedative side effects may occur, especially in patients treated by a CBZ + CLB or PHT + CLB bitherapy, and both CLB and NCLB plasma levels should be monitored in such patients.

Adolescent↗
PubMed1992

Neurological findings and seizure outcome in children with bilateral opercular macrogyric-like changes detected by MRI.

The authors studied 10 patients aged between six and 23 years (mean age 14 years 5 months) with magnetic resonance imaging, which detected bilateral 'macrogyric-like' maldevelopment of the insulo-opercular regions. The data confirm that biopercular gyral anomaly, associated with mental retardation, pseudobulbar palsy (cortical or central) and epilepsy, represents an anatomo-clinical syndrome. Nevertheless, a wide clinical spectrum was found varying from pictures correlating with the topography and extent of the MRI-detected anomaly to conditions indicating wider cerebral involvement. Epilepsy, varying greatly in age at onset and severity, consistently influenced the prognosis for five patients with diffuse EEG abnormalities and intractable seizures with falls. Anterior callosotomy relieved such seizures in one case.

Adolescent↗
PubMed1992

Epilepsy and focal gyral anomalies detected by MRI: electroclinico-morphological correlations and follow-up.

The authors studied 10 patients (mean age 15 years 6 months) with localized developmental gyral disorder detected by MRI. There were two groups of major malformations. Seven patients (group 1) had unilateral 'macrogyric-like' insulo-opercular changes, one of whom died early in life and had extensive microgyria. The six others had mental retardation and epilepsy, three of whom had focal neurological signs. Age at onset of epilepsy varied greatly. Clinical and EEG data suggested a wider cerebral involvement than recognized on MRI. The remaining three patients (group 2) had abnormal gyri of variable topography and extension, with bulging grey matter and ventricular deformity. One had mental retardation, another had neurological signs. All had intractable complex partial seizures and focal EEG anomalies correlating with the MRI lesion site, pointing to a well-defined epileptogenic zone. No clinical or EEG evidence of significant malformation in the remaining brain tissue was observed. Ablative surgery was beneficial for one patient; focal cortical dysplasia was the pathological substrate.

Adolescent↗
PubMed1992

[Not Available].

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Biology↗
PubMed1992

The electrical status epilepticus syndrome.

The authors review the clinical and electroencephalographic features of electrical status epilepticus during slow sleep (ESES) in children. The major points of debate regard the nosology and diagnosis of ESES. The relationship between ESES and the neuropsychological impairment is emphasized. It is concluded that ESES is a separate electro-clinical entity which deserves individual categorization.

Cerebral Cortex↗
PubMed1991

[The role of mitochondrial encephalopathies in progressive myoclonus epilepsy].

The authors compare the clinical, neurophysiological and evolutive features of progressive myoclonus epilepsy (PME) associated with mitochondrial encephalomyopathy with ragged-red fibers (MERRF), based on 49 cases from the literature, and the two well-described types of degenerative PME: Baltic myoclonus (BM), of which over 100 cases have been reported from Finland, and Mediterranean myoclonus (MM), based on a personal series of 43 patients. Degenerative PMEs are age-dependent, recessively inherited conditions with homogeneous clinical signs and course; there are no major clinical symptoms beside the cardinal symptoms: generalized epileptic seizures, predominantly action myoclonus and cerebellar dysfunction; mental deterioration when present, is slight and progresses very slowly; associated neurological symptoms are uncommon and limited to mild spino-cerebellar involvement. In MERRF, the transmission is maternal, the age of onset is variable, the evolution is not stereotyped and associated symptoms are many (deafness, muscle weakness, optic atrophy, short stature, sensory disturbances, spasticity, clinical or neurophysiological signs of peripheral neuropathy, absence of motor reflexes); muscle biopsy generally shows ragged-red fibers. The differential diagnosis between these conditions is usually easy, although pathological examination (i.e. muscle biopsy) should be performed.

Biopsy↗