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Biomedical subjects

E Hirsch

Publications and source records attributed to E Hirsch.

At least 19 recordsLinked to original sources
PubMed2006

[Selective memory impairment for public events associated with accelerated forgetting in a patient with left temporal lobe epilepsy].

BACKGROUND: Memory for the past has been much less explored than anterograde memory in temporal lobe epilepsy. No data are available about the course after surgical treatment. Moreover, case-reports showing isolated memory deficit for publics events with preserved autobiographical memory are notorious for their paucity. METHODS: We report the case of a patient with a left hippocampal lesion associated with intractable temporal lobe epilepsy. Comprehensive neuropsychological assessments were carried out before and after temporal lobectomy, stressing particularly memory for the past by means of standardised and tailor-made tests. RESULTS: The patient exhibited preserved memory for autobiographical events and facts but impaired scores on several public event tests, in the context of preserved general abilities. Furthermore, we found an accelerated forgetting rate for verbal and non verbal material. CONCLUSION: Our findings suggest that the patient's impaired long-term consolidation might have contributed to the impaired performance on public event memory tests. We discuss the specific features of new events processing that may contribute to its increased vulnerability relative to autobiographical memory, in the event of accelerated forgetting.

Brain↗
PubMed2006

Identification of the macromolecular complex responsible for PI3Kgamma-dependent regulation of cAMP levels.

PI3Kgamma is a phosphoinositide 3-kinase characterized by both lipid and protein kinase activity. It is activated by G-protein-coupled receptors and is predominantly expressed in leucocytes; in addition, recent work showed its presence in the heart and its involvement in regulating cardiac functions. In this tissue, PI3Kgamma acts as a negative modulator of contractility, by decreasing cAMP concentration through a kinase-independent mechanism. Indeed, whereas PI3Kgamma-deficient mice show an abnormal cAMP elevation, cAMP levels in knock-in mouse mutants, expressing a kinase-dead PI3Kgamma, are comparable with wild-type controls. PI3Kgamma regulates cardiac cAMP homoeostasis by forming a macromolecular complex containing PDE3B (phosphodiesterase 3B). In this complex, PI3Kgamma could regulate PDE3B activity through protein kinase A, a PDE activator.

Animals↗
PubMed2006

[Ethical aspects for substitute decisions and their reversion in amyotrophic lateral sclerosis].

Related to its clinical characteristics, amyotrophic lateral sclerosis (ALS) is a paradigm of the ethical difficulties due to a chronic and relentless fatal disease. Its fatal evolution in relation with a respiratory failure, but mainly the choices imposed by the respiratory insufficiency at the end of live, makes that the medical team faces very difficult situations. These situation can be solved only case per case, with repeated discussion with the patients and its relatives. The appeal to the shared dossier becomes essential in this approach. It makes easier the communication, and the appropriation and sharing of information and knowledge that are necessary to anticipate the end of life decisions. ALS sparks off constantly renewed dilemmas.

Amyotrophic Lateral Sclerosis↗
PubMed2005

Childhood epilepsy syndromes with both focal and generalized seizures.

Childhood is a time of considerable importance for the onset of epilepsy syndromes. Selection of an appropriate antiepileptic drug (AED) is central to its successful management. Different AEDs have various effects depending on whether seizures are focal or generalized and this is often used as a rational basis for drug selection. Syndromes, in which features of both focal and generalized seizures are associated in a single patient, present particular problems for pediatric prescribing and epilepsy management since an AED suitable for one seizure type may be ineffective for, or even aggravate, another seizure type. This review discusses the syndromes with different seizures types, focal and generalized, examines the treatment options that may be useful in each case and highlights the potential of some of the newer AEDs in managing these difficult syndromes.

Anticonvulsants↗
PubMed2004

Regional cerebral glucose metabolism in epilepsies with continuous spikes and waves during sleep.

BACKGROUND: Epileptic syndromes with continuous spikes and waves during sleep (CSWS) represent a wide spectrum of epileptic conditions associated with cognitive dysfunctions that have the EEG pattern of CSWS as a common feature. Reported are the results of voxel-based analyses of brain glucose metabolism performed in a group of 18 children with CSWS. METHODS: Voxel-based analyses of cerebral glucose metabolism were performed using statistical parametric mapping (SPM). First, each patient was compared with a control group and the influence of age, epileptic activity, and corticosteroid treatment on metabolic abnormalities was studied. Also, disease-related changes in the contribution of a brain area to the level of metabolic activity in another brain area were investigated using pathophysiologic interactions in groups of patients compared with the control group. RESULTS: Individual SPM analyses identified three metabolic patterns: association of hypermetabolic and hypometabolic areas, hypometabolic areas only, and normal pattern. Age and intensity of awake interictal spiking did not significantly differ in patients showing focal hypermetabolism compared with the other ones. Treatment with corticosteroids was associated with absence of focal hypermetabolism. In the group of patients with hypermetabolic areas, analyses of pathophysiologic interactions showed disease-related altered functional connectivity between the parietal and frontal cortices. CONCLUSIONS: Cerebral metabolic patterns are heterogeneous among patients with CSWS. This metabolic heterogeneity could be related to the use of corticosteroid treatment before PET. The parietofrontal altered connectivity observed in patients with hypermetabolism is interpreted as a phenomenon of remote inhibition of the frontal lobes induced by highly epileptogenic and hypermetabolic posterior cortex.

Brain↗
PubMed2004

Phosphoinositide 3-kinase gamma: kinase-dependent and -independent activities in cardiovascular function and disease.

Cardiac function is controlled by GPCRs (G-protein-coupled receptors) which exert their function by triggering numerous signalling pathways, including the activation of PI3K (phosphoinositide 3-kinase). The GPCR-activated PI3Kgamma is weakly expressed in the heart, but the deletion of its expression in mice causes remarkable phenotypes. Indeed, the lack of PI3Kgamma does not modify heart rate and blood pressure, but does increase contractility, particularly in response to stimuli that enhance cardiac contractile force, such as catecholamines. Consistently, treatment of mutant cardiomyocytes with beta-adrenergic agonists causes an abnormal increase in the elevation of cAMP production. On the other hand, PI3Kgamma appears to play a role in mediating the contractile depression exerted by other GPCR agonists, such as PAF (platelet-activating factor), that are released in pathological conditions, such as after an ischaemic insult. The receptor for PAF coupled to G(i) activates PI3Kgamma, which, in turn, is essential to promote Akt phosphorylation, NOSIII (nitric oxide synthase isoform III) activation and the production of nitric oxide, a well characterized cardiodepressing agent. As a whole, PI3Kgamma appears to negatively control cardiac contractility through different signalling mechanisms, thus becoming a possible drug target for the treatment of critical human cardiac pathologies, such as infarction or heart failure.

Animals↗
PubMed2004

[Refractory partial epilepsy: what are the neuropediatrician's criteria for drug resistance?].

Despite the emergence of new antiepileptic drugs, 10 to 20% of children with epilepsy, half of whom have localization-related epilepsy, remain refractory to drug treatment. Careful syndromic identification is essential before retaining the diagnosis of intractable childhood epilepsy in order to optimize treatment and avoid iatrogenic worsening. The use of appropriate associations of new antiepileptic drugs should lead to better control in some situations, but further studies are still necessary. A significant number of children with medically intractable localization-related epilepsy may benefit from surgical treatment. Because of the cognitive consequences of epilepsy in children, the question of the appropriate time for surgery is still debated; the current trend is for early surgery in children. For many authors, intractability can be assessed after 18 months of evolution, and retained when seizures persist at a frequency of one or more a month despite more than two correctly administered antiepileptic drugs. In case of epileptogenic encephalopathy, time to surgery may be shorter. Early predictive criteria of intractability have been identified by several cohort studies and include the presence of frequent seizures at disease onset, status epilepticus, with the prevalence of certain etiologies such as encephalitis or neuronal migration disorders. Conversely, some children may develop late intractability after an early benign course; the identification or early predictive criteria is still unclear in this situation.

Adolescent↗
PubMed2004

[Children with drug-resistant partial epilepsy: criteria for the identification of surgical candidates].

The majority of candidates for epilepsy surgery, in both children and adults, belong to the syndromic category of partial epilepsies. However, particularly in children, the clinical expression of epilepsy may sometimes be misleading, as paroxysmal events may present as generalized seizures although having a focal onset. The spectrum of surgical possibilities for early-onset epilepsy has tended to widen rapidly and to include not only other focal epilepsies but also more difficult types. This is because developmental lesions that are the major cause of infantile epilepsy are often poorly localized, involve extensive brain areas and require extensive operations (e.g. hemispherotomy). Surgery is also used for progressive conditions such as Rasmussen's encephalitis or Sturge-Weber syndrome. Some forms of generalized symptomatic epilepsy may also benefit from palliative surgical procedures (callosotomy in cases with repetitive drop attacks often as a manifestation of a Lennox-Gastaut syndrome). The timing of surgery partly depends on the probable effectiveness of the operation available for each particular patient. Candidates for epilepsy surgery must be identified early in the process of the disease, thus increasing the chances for a satisfactory cognitive and behavioral outcome. The decision should be taken by experienced multidisciplinary groups, that will also ensure post-operative follow-up, both in terms of medical management and psycho-social integration. Prospective studies are still needed, to evaluate the long-term cognitive evolution of children operated on early for their epilepsy and cured. Increasing evidence indicates that drug therapy is likely to fail to achieve control of the seizures when two-three of the major drugs, properly chosen by competent clinicians, have not obtained satisfactory results, i.e. full control of seizures and absence of side effects. Testing of all possible drugs is not advisable, because this process would be excessively long when surgery is a reasonable possibility. The requirements for resective surgery in children with partial drug-resistant epilepsy vary with the type of resection considered. Three basic requirements apply to almost all cases: (a) the epileptogenic area must be localized to a territory whose removal is contemplated; (b) that no other independent epileptogenic area exists in those areas that are not included in the planned resection, and (c) that any possible deficit resulting from resection must be acceptable. The current experience confirms that the complete resection of the epileptogenic area is the major condition for a satisfactory surgical result. The possibilities for resective surgery depend upon the localization of the ictal onset zone, its relationship with adjacent functional brain areas and the availability of convergent data that point to a single localization. Epilepsy surgery mandates a multidisciplinary approach that requires special skills and sophisticated instruments and materials that cannot be improvised. A global evaluation of risks and expected benefits is always required. All decisions require a close collaboration between the epilepsy team, the patient and the family. With the exception of high quality MRI and video-EEG recording of seizures, the need to perform any other complementary presurgical investigation should be evaluated on an individual basis.

Anticonvulsants↗
PubMed2004

[Cost-effectiveness of epilepsy surgery in a cohort of patients with medically intractable partial epilepsy--preliminary results].

OBJECTIVE: Patients with medically intractable epilepsy are potential candidates for surgery if the epileptogenic tissue is localized and resectable. Surgical therapy can eliminate seizures but is very expensive. We followed a prospective adult cohort of intractable epileptic patients in order to perform a cost-effectiveness analysis. POPULATION AND METHODS: Adult patients with a suspected partial medically intractable and operable epilepsy were eligible for evaluation, explorations and/or surgery. Clinical and economical data were collected at the inclusion and every 6 months over at least two years. Two patient groups were analyzed: some underwent a surgery, others did not. Clinical data were compared between both groups. As the data collection was not yet complete, we compared the surgery to a continuation of the preoperative medical management in a cost-effectiveness analysis. Direct medical and nonmedical costs were evaluated according to a societal perspective. The effectiveness was defined as one year without seizure. We assessed the incremental cost-effectiveness ratio (ICER) for the first two years after the surgery. We also modeled long-term costs and effectiveness and extrapolated the results over the patients' lifetime with a Markov model. We computed the ICER and performed a sensitivity analysis. Indirect costs were measured in physical units and intangible costs were assessed with quality-of-life measures (QOLIE-31, SEALS). Data were compared before and after surgery. RESULTS: Among the 286 patients included, 119 did not enter in the analysis: 7 were not eligible, 44 not operable, 31 did not present a follow-up, 37 still underwent exams. Finally, 89 underwent a surgical treatment, and 78 were medically treated. Disease was more severe in surgical patients than in medical patients: seizures frequency, depressive disorders and cognitive impairment were greater. One year after the surgery, 83% patients were seizure free. During the year before inclusion and the year after surgery, direct costs were mainly due to hospitalization. During the second year after surgery, the cost of antiepileptic drugs predominated. One additional year without seizure costs 23 531 euro one year after surgery and 9533 euro two years after surgery. In a long-term perspective, the surgery became cost-effective between 7 and 8 years after the surgery. CONCLUSION: Surgical therapy is a cost-effective treatment in a middle-term even without indirect costs consideration.

Adolescent↗
PubMed2003

Loss of beta1-integrin-deficient cells during the development of endoderm-derived epithelia.

Beta1-integrins (beta1) represent cell surface receptors which mediate cell-matrix and cell-cell interactions. Fässler and Meyer described chimeric mice containing transgenic cells that express the LacZ gene instead of the beta1 gene. They observed beta1-negative cells in all germ layers at embryonic day E 8.5. Later in development, using a glucose phosphate isomerase assay of homogenized tissue samples, high levels of transgenic cells were found in skeletal muscle and gut, low levels in lung, heart, and kidney and none in the liver and spleen (Fässler and Meyer 1995). In order to study which cell types require beta1 during development of the primitive gut including its derivatives, chimeric fetuses containing 15 to 25% transgenic cells were obtained at days E 14.5 and E 15.5. They were LacZ (beta-galactosidase) stained "en bloc" and cross-sectioned head to tail. In esophagus, trachea, lung, stomach, hindgut, and the future urinary bladder, we observed various mesoderm-derived beta1-negative cells (e.g. fibroblasts, chondrocytes, endothelial cells, and smooth muscle cells) but no beta1-negative epithelial cells. Since the epithelia of lung, esophagus, trachea, stomach, hindgut, and urinary bladder are derived from the endodermal gut tube, we hypothesize that beta1 is essential for the development and/or survival of the epithelia of the fore- and hindgut and its derivatives.

Animals↗
PubMed2003

Epilepsy, antiepileptic drugs (AEDs) and cognition.

People with epilepsy are at increased risk of cognitive deficits as a result of various factors: the effect of seizures themselves, psychosocial factors and adverse effects of AEDs. It is crucial that, following early diagnosis of the correct epileptic syndrome, patients are treated with the appropriate drugs, as incorrect AEDs can exacerbate symptoms. By discussing various epileptic syndromes and performing a broad review of the available evidence, it is possible to make recommendations concerning prescription of AEDs with respect to cognition. An interesting advance in this area is the increasing use of AEDs such as valproate (in some countries divalproex is indicated), carbamazepine or lamotrigine (lamotrigine has been filed for approval in this indication) for bipolar disorders. Children and the elderly are especially vulnerable to adverse effects on cognition. This review highlights advantages of valproate in these populations; it is well tolerated and produces few cognitive side effects.

Adolescent↗
PubMed2003

The ideal characteristics of antiepileptic therapy: an overview of old and new AEDs.

New and improved anti-epileptic drugs (AEDs) have made the concept of choice, according to the individual prognosis and probable response to specific regimens, increasingly feasible. Inter-individual variability in syndrome severity and complexity make individualization necessary. We propose three categories of disorder control according to the individual objectives of the patient: (1) seizure control, (2) epilepsy control and ultimately, (3) "epilepsy cure"; the latter remaining a largely idealistic target today. An AED is likely to be successful if it exhibits "optimal" characteristics, such as drug efficacy, tolerability, pharmacokinetics, interactions and cost-effectiveness. This review discusses the "optimal" characteristics of add-on AEDs, which, in addition to seizure control, will contribute to the achievement of epilepsy control and therefore address the currently unmet clinical needs of epilepsy treatment.

Anticonvulsants↗
PubMed2003

Phosphoinositide 3-kinase gamma: a key modulator in inflammation and allergy.

Chronic inflammation and allergy involve the activation of tissue-resident cells and, later on, the invasion of effector cells. We have previously shown that the loss of phosphoinositide 3-kinase (PI3K) gamma impairs chemokine-dependent migration of neutrophils and macrophages both in vitro and in vivo. On the other hand, PI3K gamma is not required either during phagocytic processes or in the activation of bactericidal activities like granule secretion and particle-mediated respiratory burst in neutrophils. Tissue mast cells are key regulators in allergy and inflammation and release histamine upon clustering of their IgE receptors. We have demonstrated that murine mast cell responses are exacerbated in vitro and in vivo by autocrine signals, and require functional PI3K gamma. Adenosine, acting through the A(3) adenosine receptor, as well as other agonists of G(alpha i)-coupled receptors, transiently increased PtdIns(3,4,5) P (3) exclusively via PI3K gamma. PI3K gamma-derived PtdIns(3,4,5) P (3) was instrumental for initiation of a sustained influx of external Ca(2+) and degranulation. Mice that lacked PI3K gamma did not form oedema when challenged by passive systemic anaphylaxis. PI3K gamma thus relays inflammatory signals through various GPCRs, and is thus central to mast cell function. Taken together, this suggests that pharmaceutical targeting of PI3K gamma might alleviate inflammation at both early and late stages of the allergic response.

Animals↗
PubMed2002

Contribution of SISCOM imaging in the presurgical evaluation of temporal lobe epilepsy related to dysembryoplastic neuroepithelial tumors.

PURPOSE: Dysembryoplastic neuroepithelial tumors (DNTs) are a group of glioneuronal supratentorial and intracortical lesions often associated with the early onset of intractable and crippling partial seizures. They are characterized by their location, multinodular architecture, and heterogeneous cell composition, with a specific glioneuronal element in the specific form. Foci of cortical dysplasia may be associated with the tumoral lesion, and identifying the presence and the extent of cortical dysplasia is not always easy on magnetic resonance images (MRIs). The purpose of this article is to evaluate, retrospectively, the usefulness of ictal single-photon emission computed tomography (SPECT) imaging to assess the presence and the extent of cortical dysplasia associated with DNTs in nine patients with intractable temporal lobe epilepsy related to histopathologically confirmed DNTs. METHODS: The results of the subtraction of ictal and interictal SPECT coregistered to MRI (SISCOM) were compared with the results of the examinations of pathological material after surgery. RESULTS: SISCOM showed a strongly hyperperfused area corresponding anatomically to electroclinical abnormalities and to the location of DNTs on MRI. A circumscribed hyperperfusion was present in DNTs without cortical dysplasia, limited to the location of the tumor on MRI. In cases of associated cortical dysplasia, a widespread hyperperfusion including areas corresponding to normal perilesional regions on MRI was found. CONCLUSIONS: SISCOM, used among presurgical investigations, contributes to detecting cortical dysplasia associated with DNTs. Concordance between the symptomatogenic zone (defined from the medical history and electroclinical data), MRI scans, SISCOM pattern, and complete resection of the epileptic zone was predictive of a good postsurgical outcome.

Adolescent↗