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Biomedical subjects

A Rougier

Publications and source records attributed to A Rougier.

At least 37 records · Page 2Linked to original sources
PubMed1998

Granule cell dispersion is correlated with early epileptic events in human temporal lobe epilepsy.

Granule cell dispersion (GCD) into the dentate gyrus (DG) molecular layer was observed in hippocampal specimens in 10 out of 22 cases of human non-lesional temporal lobe epilepsy (TLE) and was associated with hippocampal sclerosis (HS). The presence of GCD was significantly linked to events of epileptic nature arising during the first 4 years of life but not with the durations of epilepsy, nor the number of seizures. Dispersion could be induced by seizure-linked structural plasticity occurring during a specific early permissive period.

Cell Death↗
PubMed1998

p53 protein expression in grade II astrocytomas: immunohistochemical study of 100 cases with long-term follow-up.

p53 protein expression was evaluated by immunohistochemistry in a homogeneous series of 100 supratentorial grade II astrocytomas with long-term follow-up. The staining was positive in 72 cases. The proportion of p53 positive tumors was slightly higher in younger patients. The tumor regrowths which derived from p53 positive tumors were themselves p53 positive, and this p53 immunopositivity was often stronger than in the initial tumors. All of the 10 gemistocytic astrocytomas included in our series were p53 positive, and age more than histological type appeared decisive in prognosis. p53 protein expression did not quite reach statistical significance as an independent predictive variable in multivariate analysis, whereas survival was related with age, mass effect, surgery and tumor location. Only a tendency to a longer survival was observed on the curves in younger patients with mildly positive tumors.

Adolescent↗
PubMed1998

[Temporal lobe epilepsy and ganglioglioma in children. Clinical aspects, imagery and neuropathology; nosological discussion of six cases].

BACKGROUND: Gangliogliomas belong to debated nosological entity. They are classified as neuronal or neuroglial tumors. PATIENTS AND METHODS: Six children aged from 4 months to 15 years (mean age: 4 years and 6 months) were initially seen for partial seizures resistant to treatment. Tumoral resection was performed in all six. Diagnosis was made from immunohistological study of the tumor. DISCUSSION: Gangliogliomas are non-malignant, with a good prognosis, even if inaugural clinical manifestations are severe. Neuroradiological diagnosis with astrocytomas and cortical dysplasia is not easy, and pathological distinction from cortical dysplasia is difficult. CONCLUSION: The immunohistochemical confirmation of diagnosis permits a logical therapeutic attitude: complete resection of tumor is followed by an excellent outcome.

Adolescent↗
PubMed1998

Efficacy of protective creams in a modified repeated irritation test. Methodological aspects.

The effect of 3 protective creams and petrolatum was tested in a repetitive irritation test. On 15 healthy volunteers, the irritants (sodium lauryl sulfate 10%, sodium hydroxide 0.5%, lactic acid 15%, and toluene undiluted) were applied on the paravertebral skin of the mid-back after 30 min pretreatment with the products tested. The volunteers were treated for 9 days. The irritant cutaneous reactions were quantified by erythema score, transepidermal water loss, and chromametry. The results showed a specific profile of efficacy against the 4 irritants used. For all creams a significant protective effect was obtained against irritation by sodium lauryl sulfate, sodium hydroxide and lactic acid in different degrees. Less efficacy was observed against toluene. Even an amplification of inflammation by pretreatment with 1 product could be demonstrated. The results indicate that a 1-week period of cumulative irritation might be enough to evaluate the efficacy of protective creams against most irritants.

Adult↗
PubMed1998

Location of the epileptic zone and its physiopathological effects on memory-related activity of the temporal lobe structures: a study with intracranial event-related potentials.

PURPOSE: Neuropsychological research with epileptic patients has suggested that the location of seizure focus may be an important variable determining the nature and severity of memory impairments. According to this assumption, this study was designed to investigate the effects of the location of the epileptic zone on the memory-related activity recorded directly from different temporal lobe structures. METHODS: Intracranial event-related potentials (ERPs) were recorded during a continuous recognition memory task, which is known to elicit the modulation of N400 and P600 components (i.e., the ERP old/new effect). The patients were separated into three groups according to the location of their epileptic zone: unilateral temporal (UTE), temporal plus extratemporal (TEE), and bitemporal (BTE). Recordings were obtained from three temporal lobe structures: hippocampus, amygdala, and lateral temporal cortex. RESULTS: The results showed that in the hippocampus, the ERP old/new effect was abolished in the TEE group only. In the amygdala, although largely unaffected, the ERP modulation appeared to be more impaired in UTE patients. Contrasting with these data is the observation that the magnitude and reliability of the ERP old/new effect recorded at the neocortical level increases as the epileptic zone extends to the temporal lobes (i.e., BTE>TEE>UTE). CONCLUSIONS: It is concluded that the memory-related activity modulation of memory ERPs recorded from different temporal lobe structures is affected differently by the presence of an epileptic zone as a function of its location. The possible clinical implications of these findings in surgery planning are also discussed.

Adolescent↗
PubMed1998

[Seizure-linked hippocampal plasticity and protection against excitotoxicity: possible role of neuropeptide-y].

BACKGROUND AND PURPOSE: Changes occurring in neuropeptide-Y immunoreactivity after kainic acid injection in rats and their possible consequences on seizure-brain damage were studied. METHODS: First, an intra-hippocampal kainic acid injection was performed (n = 7), inducing an ectopic and bilateral neuropeptide-Y immunoreactivity in mossy fibers. On the side of the injection, this neuropeptide-Y staining was associated with dramatic neuronal loss whereas, in the contralateral hippocampus staining was observed without associated neuronal loss. The CA3 a-b pyramidal cell loss induced by an intra-ventricular kainic acid injection was then compared between a control group (n = 6) and a pre-conditioned group (n = 6) characterized by neuropeptide-Y staining in the mossy fibers obtained by a previous contralateral intra-hippocampal kainic acid injection as described. RESULTS: In the pre-conditioned group, the CA3 a-b pyramidal cell loss was significantly lower (m = 33.5%) than in the control group (m = 86.6%). The neuropeptide-Y inhibiting the pre-synaptic release of glutamate, glutamate-related epileptic-brain damage could be reduced when neuropeptide-Y is expressed by granulated cells. IN CONCLUSION: Seizure-linked plasticity could induce a self-protection phenomenon against excitotoxic lesions possibly partially mediated by de novo neuropeptide-Y mossy fiber expression.

Animals↗
PubMed1997

Induction of tolerance and mossy fibre neuropeptide-Y expression in the contralateral hippocampus following a unilateral intrahippocampal kainic acid injection in the rat.

We have previously reported an ectopic expression of neuropeptide-Y (NPY) immunoreactivity in mossy fibres (MFs) in the contralateral hippocampus following a unilateral intrahippocampal (IH) injection of kainic acid (KA). In the present study we report that, in addition to MF NPY expression, unilateral IH KA injections also induce tolerance towards a subsequent intracerebroventricular (ICV) contralateral KA injection, resulting in a reduction in the number of overt seizures and degree of cell loss.

Animals↗
PubMed1997

Possible mechanisms inducing granule cell dispersion in humans with temporal lobe epilepsy.

The stratum granulosum (SG) of the fascia dentata from 17 human epileptic hippocampi was assessed in terms of width, volumetric cell density (VCD) and percentage of cell loss to study the granule cell dispersion (GCD) phenomenon described by Houser. GCD was considered when three conditions were observed, the SG was wider than 120 microns, granule cell (GC) somata did not remain in close apposition to one another the normal clear boundary between the molecular layer and the SG was not maintained. GCD involved a partial zone of the SG in six cases and the whole SG in two cases. Dynorphin mRNA in-situ hybridization was performed in two cases and allowed us to affirm that dispersed cells are actually GC. A close correlation linked GCD, GC loss and VCD decrease in diffuse CA4, laminated CA4, CA3, CA2 and CA1. The discussion is focused on the possible causes of dispersion. Some arguments did not suggest for a migration arrest during development. Nevertheless, in one case, a cluster of horizontal cells in the inner part of the molecular layer could evoke the persistence of normally transient cells during ontogenesis. A neo-migration due to permissive phenomenon induced by gliogenesis, mossy fibers sprouting in the supra-granular layer and over-expression of growth factors is suggested from experimental data. Nevertheless a straining due to the tissue shrinkage observed in severe hippocampal sclerosis (HS) could also be involved in the origin of GCD.

Adolescent↗
PubMed1997

High-frequency stimulation of the globus pallidus internalis in Parkinson's disease: a study of seven cases.

The effectiveness of ventroposterolateral pallidotomy in the treatment of akinesia and rigidity is not a new discovery and agrees with recent investigations into the pathogenesis of Parkinson's disease, which highlight the role played by the unbridled activity of the subthalamic nucleus (STN) and the consequent overactivity of the globus pallidus internalis (GPi). Because high-frequency stimulation can reversibly incapacitate a nerve structure, we applied stimulation to the same target. Seven patients suffering from severe Parkinson's disease (Stages III-V on the Hoehn and Yahr scale) and, particularly, bradykinesia, rigidity, and levodopa-induced dyskinesias underwent unilateral electrode implantation in the posteroventral GPi. Follow-up evaluation using the regular Unified Parkinson's Disease Rating Scale has been conducted for 1 year in all seven patients, 2 years in five of them, and 3 years in one. In all cases high-frequency stimulation has alleviated akinesia and rigidity and has generally improved gait and speech disturbances. In some cases tremor was attenuated. In a similar manner, the authors observed a marked diminution in levodopa-induced dyskinesias. This could be an excellent primary therapy for younger patients exhibiting severe bradykinesia, rigidity, and levodopa-induced dyskinesias, which would allow therapists to keep ventroposterolateral pallidotomy in reserve as a second weapon.

Adult↗
PubMed1997

Callosotomy for intractable epilepsy: overall outcome.

The effectiveness of callosotomy to the control of medically intractable epilepsy is still discussed fifty years after the first reported cases. Nevertheless patient selection, type of seizures and epileptic syndromes are now better determined. Atonic and tonic astatic seizures characterized both by clinical and electroencephalographical specific patterns, are the most responsive. A favorable outcome, from > 50% reduction in seizure frequency to a complete cessation, is obtained from 60 to 80% of the patients. For tonic-clonic seizures, favorable outcome fluctuates from 40% to 80% principally according to the extension of the section. Other types of seizures are not indicated for callosotomy even though some improvement may be observed. Symptomatic secondary generalized epilepsy with predominent unilateral lesion and epileptic focus on bifrontal lobe epilepsy are the most suitable indication. True generalized epilepsies are associated with a less favorable outcome. Indeed, axial spasms, the most frequent type of drop attacks in the Lennox-Gastaut syndrome, probably do not have a cortical origin. Quality of life and social adjustment are assessed from a cohort of 20 cases of anterior two-third callosotomy. Actual benefits are in close connection with both seizure relief and age at operation. To obtain a gain in social independence not only seizure control has to be better but also surgery must be performed sooner.

Corpus Callosum↗
PubMed1996

Widespread ectopic neuropeptide-Y immunoreactivity in contralateral mossy fibres after a unilateral intrahippocampal kainic acid injection in the rat.

Granule cells of the dentate gyrus can express neuropeptide-Y (NPY) in several models of epilepsy involving limbic seizures, however, the nature of this ectopic expression is not well understood at present. We have studied the expression of NPY-immunoreactivity in mossy fibres contralateral to a unilateral intrahippocampal injection of kainic acid and report that ectopic mossy fibre NPY-immunoreactivity is observed throughout the contralateral hippocampus.

Animals↗
PubMed1996

Multiple subpial transection: report of 7 cases.

7 cases of pure multiple subpial transection (MST) without associated cortical resection, for treatment of pharmaco-resistant partial epilepsy localized in highly functional cortical area, are reported. The transections were performed following the technique described by Morrell. The follow-up period ranged from 1 to 4 years. MST induced no significant neurological handicap: only 2 patients experiencing a transitory sensory-motor deficit and with total recovery within 1 month. With respect to seizures, 5 patients were improved with a decrease in seizure frequency of 100, 95, 75, 60 and 40%, respectively. Complex partial seizures changed postoperatively into simple partial seizures in 1 case. In conclusion, this procedure seems to be adequate, although no statistically significant results are available at this time. In our series, we believe failures could be attributed to either a very restricted area of transection or to an incorrect delimitation of the epileptic focus.

Adult↗
PubMed1996

Differential involvement of the human temporal lobe structures in short- and long-term memory processes assessed by intracranial ERPs.

Intracranial event-related potentials (ERPs) elicited during a recognition memory task were recorded in 25 epileptic patients by using depth electrodes sampling four different regions within the temporal lobe (amygdala, hippocampus, anterior and posterior temporal cortices). The task was a continuous recognition memory task in which repeated items were presented after 6 or 19 intervening items following their first presentation. This study was performed to investigate the respective role of the different temporal lobe structures in short-term memory (STM) and long-term memory (LTM) processing. Subregions of the temporal lobe were differently involved in these two memory systems. The posterior temporal cortex is specifically involved in STM processing, whereas the amygdala, hippocampus, and anterior temporal cortex contribute to both STM and LTM. Moreover, it appeared that the latter structures play their own role in LTM. The anterior temporal cortex and amygdala may contribute to recency discrimination, and the hippocampus seems rather to be involved in maintaining memory traces. These findings suggest that the temporal lobe structures may function in a complementary way by subserving different aspects of information processing.

Adolescent↗
PubMed1996

Effect of imidazole derivatives on cytochrome P-450 enzyme activities in a reconstructed human epidermis.

We tested the effect of various imidazole derivatives applied topically, on P-450-dependent enzyme activity of a reconstructed epidermis in conditions simulating clinical use. At nontoxic concentrations (determined by a cytotoxicity test based on the reduction of a tetrazolium salt, MTT, by mitochondrial deshydrogenase) econazole and clotrimazole had a biphasic effect on 7-ethoxycoumarin-O-deethylase (ECOD) activity in the epidermis, with induction at low concentrations and inhibition at high concentrations. Dermatological preparations (emulsions, gels) containing imidazole derivatives, which are nontoxic for the epidermis, decreased ECOD activity by about 40% 18 h after topical application. These results are in keeping with in vivo observations after topical application, and stress the value of the reconstructed epidermis for pharmacotoxicological and mechanistic studies of topical agents used in dermatology.

7-Alkoxycoumarin O-Dealkylase↗
PubMed1995

Effects of temporal versus temporal plus extra-temporal lobe epilepsies on hippocampal ERPs: physiopathological implications for recognition memory studies in humans.

The present experiment was designed to investigate the incidence of temporal and extra-temporal epileptogenic lesions on hippocampal activity related to recognition memory. Hippocampal event-related potentials (ERPs) were recorded during a recognition memory task for pictures in patients with unilateral temporal lobe epilepsy and in patients with combined temporal and extra-temporal (frontal or parietal) epileptogenic foci. In the first group, the comparison between correctly recognized pictures and new distractors revealed that the usual ERP (N400/P600) 'old/new' effects were not dramatically affected by the presence of a temporal epileptogenic lesion. In contrast, these effects were absent in multifocal epilepsy patients, indicating that frontal and parietal brain regions play a part in the modulation of hippocampal ERP and related memory processing. These results suggest that ERP 'old/new' effects are dependent on interactions between frontal, parietal and medial temporal structures. Together with the results of other recent studies devoted to locating the neural sources of N400 and P600, the present findings provide physiopathological evidence that ERP 'old/new' effects are subtended by distributed yet interconnected brain regions that are known to play an important role in recognition memory processing.

Adult↗
PubMed1995

Intracranial topography of event-related potentials (N400/P600) elicited during a continuous recognition memory task.

To isolate the anatomical locus of the neural activity most important for generating or modulating the scalp-recorded N400 and P600 components elicited during continuous recognition memory tasks, intracranial event-related potentials (ERPs) were recorded from medial and lateral aspects of the temporal, frontal, parietal, and occipital lobes in 25 patients undergoing stereoelectroencephalography for seizure localization. Large-amplitude and polarity-inverted ERPs were recorded from various temporal, frontal, and parietal structures, whereas the memory-related ERP modulation assessed by the ERP repetition effect was present only in those brain areas that play the most important role in memory processing. These data suggest that the scalp-recorded N400 and P600 components may represent the most readily observable aspect of synchronous activity occurring across widely distributed brain structures and neural systems underlying different cognitive mechanisms, which all contribute to some aspect of information processing during recognition memory.

Adolescent↗
PubMed1995

Surgical treatment of an early epileptic encephalopathy with suppression-bursts and focal cortical dysplasia.

A case of early epileptic encephalopathy (EIEE) with suppression-bursts or Ohtahara's syndrome, associated with focal cortical dysplasia is reported. Infantile spasms and brief tonic unilateral seizures began on the fifth day of life. Interictal EEG demonstrated an asymmetrical "suppression-burst" pattern with no wake or sleep cycling. Seizures were refractory to all antiepileptic drug (AED) and steroid therapy. Magnetic resonance imaging (MRI) showed right frontotemporal cortical thickening. After three weeks of an ineffective medical treatment a preoperative evaluation with single photon emission computed tomography (SPECT) and electrocorticography (ECoG) was performed to characterize epileptogenic focus. Surgical resection of the precentral area was performed at age 1 month. Neuropathologic examinations confirmed diagnosis of focal cortical dysplasia by identifying cytoarchitectural disarray and ectopic neurons located deep in subcortical white matter. During follow-up, 1-year postoperative the child had a single febrile seizure. Neurologic examination showed minor developmental delay and slight left-sided weakness.

Age Factors↗