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Biomedical subjects

A Rougier

Publications and source records attributed to A Rougier.

At least 19 recordsLinked to original sources
PubMed1999

Correlations between granule cell dispersion, mossy fiber sprouting, and hippocampal cell loss in temporal lobe epilepsy.

PURPOSE: Correlations between granule cell dispersion (GCD), collateral mossy fiber (MF) sprouting, and hippocampal cell loss were studied to assess the relation between GCD and synaptic reorganization in the dentate gyrus of patients with epilepsy. METHODS: Twenty specimens from patients with medically intractable temporal lobe epilepsy (TLE) were studied along with two control specimens. GCD was considered to be present when the stratum granulosum was wider than 120 microm, the close apposition between the granule cell (GC) soma was lost, and GCs were scattered in the molecular layer (ML). Patterns of MF sprouting were differentiated as wide or narrow according to the area of neo-Timm's staining in the ML. GC loss and volumetric cell-density decreases in the different subfields were assessed. RESULTS: MF sprouting was observed in 16 (80%) and GCD in nine (45%) cases. A significant correlation was found between MF sprouting and cell loss in all the subfields except the cornu Ammonis field 2 (CA2). A wide band of MF sprouting was associated with severe cell loss. Cases with GCD had a wide band of MF sprouting and also a higher degree of cell loss than cases without GCD. CONCLUSION: GCD is associated with a specific pattern of MF sprouting, but cell loss was found to be a major determinant for MF reorganization.

Adult↗
PubMed1999

Short- and long-delay intracranial ERP repetition effects dissociate memory systems in the human brain.

Prior exposure to a stimulus can facilitate the performance to subsequent presentations of that stimulus. ERP studies have shown that this facilitation is associated with the modulation of two components (N400 and P600). Investigation of the time course of both behavioral and ERP repetition effects have led to the assumption that it is subserved by the combination of at least two mechanisms operating at different time-points: a short-delay semantic activation and a long-lasting episodic mechanism. The present experiment recorded intracranial ERPs from various structures during a continuous recognition memory task to investigate the respective contribution of the different brain regions to short- and long-delay ERP repetition effects. The results are in good agreement with both the classical neuropsychological literature and the more recent data obtained with functional imagery techniques. They provide electrophysiological evidence of multiple anatomo-functional memory systems in the human brain: a short-term semantic activation system and a long-term episodic memory system, with interface structures that coordinate the functioning of these two systems.

Adolescent↗
PubMed1999

Bilateral decrease in interictal hippocampal blood flow in unilateral mesiotemporal epilepsy.

OBJECT: The goal of this study was to determine whether regional cerebral blood flow (rCBF) changes that were found contralaterally to a verified unilateral epileptic focus were associated with the spatiotemporal organization of epileptic abnormalities. METHODS: The CBF in both hippocampi was assessed using stable Xe-enhanced computerized tomography in a series of 19 patients with unilateral mesiotemporal epilepsy. Results were compared according to the distribution of interictal spiking and the spatiotemporal organization of the ictal discharges as determined by stereoelectroencephalography. Two groups were defined: in Group 1 (nine patients), the discharge remained unilateral; in Group 2 (10 patients), the discharge spread to contralateral mesiotemporal structures. For Group 1, the rates of ipsi- and contralateral hippocampal blood flow (HBF) were 32.88+/-15.53 and 45.88+/-17.19 ml/100 g/minute, respectively, whereas in Group 2 they were 36.7+/-11.54 and 36.4+/-11.27 ml/100 g/minute (mean+/-standard deviation). A two-way analysis of variance combining type of seizure (Group 1 compared with Group 2) and HBF (ipsi- compared with contralateral absolute values) demonstrated a main effect for HBF (F[1,17] = 5.051; p = 0.0382), a significant interaction between the two factors (F[1,17] = 6.188; p = 0.0235), and no main effect for type of seizure (F[1,17] = 0.258; p = 0.6178). CONCLUSIONS: In unilateral mesiotemporal epilepsy, asymmetrical interictal hippocampal perfusion was correlated with restricted unilateral ictal discharges, whereas bilateral hippocampal hypoperfusion was correlated with ictal discharges spreading to the contralateral mesiotemporal structures. The lack of correlation between the degree of hypoperfusion and the percentage of neuron cell loss indicated that the decrease in rCBF has both functional and lesional origins.

Adolescent↗
PubMed1999

Sebum rheology evaluated by two methods in vivo. Split-face study of the effect of a cosmetic formulation.

Modulation of the rheological characteristics of sebum at the surface of the skin might represent a valuable strategy for the treatment of seborrhea. In this field, only a small number of studies have addressed sebum diffusion within the stratum corneum. In an open, split-face study conducted on 20 men, we measured the sebosuppressive effect of Effidrate cream which is based on a glycerol alkyl-ether. Measurements were made in the morning at three-week intervals for a total period of 3 months. Sebum casual levels and sebum excretion rates were measured using a SM810 Sebumeter. Lipid-absorbent Sebutape was also used to collect all the sebum released from infundibular reservoirs over a four-hour period. Clinical assessments were relatively uninformative but the photometric measurements showed that Effidrate cream had a sebosuppressive action. The underlying biological mechanism remains unclear but a hypothesis based on enhanced sebum absorption by the stratum corneum is discussed.

Administration, Cutaneous↗
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↗