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Biomedical subjects

P Langevin

Publications and source records attributed to P Langevin.

At least 19 recordsLinked to original sources
PubMed1999

Topiramate in intractable childhood onset epilepsy--a cautionary note.

OBJECTIVES: To study the effectiveness and safety of topiramate in clinical practice, for a group of patients with childhood onset epilepsy. METHODS: All patients treated with topiramate at the three study centers between November 1995 and December 31, 1997 were analyzed retrospectively, using a standardized study protocol. Data were gathered on demographic features, seizures response and medication related adverse events. RESULTS: Eighty-seven patients were treated with topiramate. Over 90% seizure reduction was achieved in 8 (9%) patients, 50%-90% in 21 (24%), < 50% in 54 (62%) patients. Four patients (5%) had a deterioration in seizure control. Adverse events required topiramate discontinuation in 36 (41%). Of these 27 (31%) complained of unacceptable cognitive dulling. The rate of dose escalation and final dose in mg/kg were similar in those who remained on topiramate and those who were intolerant because of cognitive side effects. CONCLUSIONS: Although topiramate resulted in > 50% seizure reduction in 29 (33%) of this group of patients with difficult epilepsy, its usefulness was limited by a high incidence of adverse effects. Adverse events prevented ongoing therapy for 36 (41%) and cognitive dulling resulted in topiramate discontinuation by 27 (31%) of the group.

Adolescent↗
PubMed1999

Mapping of a gene determining familial partial epilepsy with variable foci to chromosome 22q11-q12.

We identified two large French-Canadian families segregating a familial partial epilepsy syndrome with variable foci (FPEVF) characterized by mostly nocturnal seizures arising from frontal, temporal, and occasionally occipital epileptic foci. There is no evidence for structural brain damage or permanent neurological dysfunction. The syndrome is inherited as an autosomal dominant trait with incomplete penetrance. We mapped the disease locus to a 3. 8-cM interval on chromosome 22q11-q12, between markers D22S1144 and D22S685. Using the most conservative diagnostic scheme, the maximum cumulative LOD score was 6.53 at recombination fraction (straight theta) 0 with D22S689. The LOD score in the larger family was 5.34 at straight theta=0 with the same marker. The two families share an identical linked haplotype for >/=10 cM, including the candidate interval, indicating a recent founder effect. A severe phenotype in one of the probands may be caused by homozygosity for the causative mutation, as suggested by extensive homozygosity for the linked haplotype and a bilineal family history of epilepsy. An Australian family with a similar phenotype was not found to link to chromosome 22, indicating genetic heterogeneity of FPEVF.

Australia↗
PubMed1997

Function and organization in dysgenic cortex. Case report.

Cerebral dysgenesis is a subject of interest because of its relationship to cerebral development and dysfunction and to epilepsy. The authors present a detailed study of a 16-year-old boy who underwent surgery for a severe seizure disorder. This patient had dysgenesis of the right hemisphere, which was composed of a giant central frontoparietal nodular gray matter heterotopia with overlying large islands of cortical dysplasia around a displaced central fissure. Exceptional insight into the function, biochemistry, electrophysiology, and histological structure of this lesion was obtained from neurological studies that revealed complementary information: magnetic resonance (MR) imaging, [18]fluoro-2-deoxy-D-glucose positron emission tomography (PET), functional PET scanning, proton MR spectroscopic (1H-MRS) imaging, intraoperative cortical mapping and electrocorticography, in vitro electrophysiology, and immunocytochemistry. These studies demonstrated compensatory cortical reorganization and showed that large areas of heterotopia and cortical dysplasia in the central area may retain normal motor and sensory function despite strikingly altered cytoarchitectonic organization and neuronal metabolism. Such lesions necessitate appropriate functional imaging studies prior to surgery and cortical mapping to avoid creating neurological deficits. Integrated studies, such as PET, 1H-MRS imaging, cortical mapping, immunocytochemistry, and electrophysiology may provide information on the function of developmental disorders of cerebral organization.

Adolescent↗
PubMed1995

Recommended biocontainment features for research and diagnostic facilities where animal pathogens are used. First International Veterinary Biosafety Workshop.

Recommendations are presented for the minimum structural components, special utilities, installations, and other design and operational features which define a microbiologically-secure animal containment facility. These biocontainment parameters are expected to enable the safe housing and handling of livestock and poultry infected with pathogenic agents. Physical testing and certification requirements for commissioning such facilities are described. Such a facility will minimise personnel exposure to infectious agents, limit cross-contamination between experiments, minimise horizontal transmission between research animals, and reduce the likelihood of pathogenic agents being released to the outside environment.

Animals↗
PubMed1993

Stages and patterns of centrifugal arrest of diffuse neuronal migration disorders.

Centrifugal migration of newly generated neuroblasts toward the cortical surface can be arrested at different levels, resulting in anatomically different disorders. This is illustrated by three patients with diffuse or generalized neuronal migration disorders (NMDs): pachygyria, subcortical laminar heterotopia ('double-cortex' syndrome), and periventricular laminar heterotopia. All had medically intractable partial and generalized epileptic seizures, but there was no close correlation between the type of dysplasia and intelligence or clinical pattern. The low intelligence found in these patients may relate to the epileptic syndrome, rather than to the NMDs alone. MRI suggested that in this spectrum of disorders the migration process was arrested at different stages, depending on the extent, timing and site of damage to radial glial fibres.

Adult↗
PubMed1990

[Motor and sensory neuropathies with or without agenesis of the corpus callosum: a radiological study of 64 cases].

In 1971, Andermann and Andermann described an autosomal recessive syndrome found within the Charlevoix and the Saguenay populations (Quebec, Canada) characterized by agenesis of the corpus callosum (ACC) associated with motor and sensory neuropathy, mental retardation and dysmorphic features. A study of CT in 64 patients demonstrated a total ACC in 37 cases (57.8%), partial ACC in 6 cases (9.4%) and the presence of the corpus callosum in 21 cases (32.8%). The latter was confirmed by MRI in 3 cases. CT of patients without ACC revealed a high frequency of developmental or degenerative midline anomalies, particularly interhemispheric fissure enlargement and posterior fossa atrophy. The clinical presentation and the natural course of the neuropathy, the intellectual impairment and the behavioural manifestations are identical amongst individuals with or without ACC. Individuals with or without ACC are found within the same family and often within the same sibship. These observations support the hypothesis of a single genetic syndrome in which the constant manifestation is the motor and sensory neuropathy.

Adolescent↗
PubMed1989

Routine screening of blood and urine for severe reactions to anticonvulsant drugs in asymptomatic patients is of doubtful value.

Severe or fatal reactions to anticonvulsant agents are fortunately rare. We examined the value of routine screening of blood and urine to detect early signs of such reactions in asymptomatic patients. The basic assumptions of this type of screening program have been faulty or unproven, and the results of studies, although not definitive, have not supported the value of such programs. Our recommendations, approved by the Canadian Association for Child Neurology, suggest that asymptomatic patients not undergo routine screening of blood and urine but, rather, be informed of the early symptoms of severe toxic reactions and be asked to report them immediately to a physician.

Adult↗
PubMed1989

Generalized cortical dysplasia manifested by diffusely thick cerebral cortex.

Unilateral or bilateral rolandic macrogyria has been described as a cause of epilepsy and, in some cases, retardation. Tissue from the periphery of these lesions shows the changes of focal cortical dysplasia. Evidence reported herein suggests that cortical dysplasia may also be generalized. Two patients with intractable epilepsy and mental retardation had diffusely abnormal, thick cortex, shallow gyri, and poor demarcation of gray and white matter. One patient had an anterior callosotomy that led to considerable improvement of the epilepsy. Cortical layers 5 and 6 could not be differentiated on biopsy material. The white matter was poorly myelinated and contained clusters of heterotopic neurons. This syndrome, a congenital disorder of neuronal migration, with prolonged survival, represents a mild form of lissencephaly. It can be diagnosed during life by computed tomography or magnetic resonance scanning.

Adolescent↗
PubMed1989

Atypical angina in patients with coronary artery disease suggests panic disorder.

The occurrence of psychiatric disorders in patients with "medical" problems is not only possible but may be even facilitated by these problems. This article examines the relationship between the type of chest pain and the diagnosis of panic disorder among coronary artery disease (CAD) patients. Forty-nine such cardiology patients were interviewed using a structured instrument. Forty percent of patients with atypical angina met DSM-III-R criteria for current panic disorder while no panic disorder was identified in the typical angina group. This finding should have great implications for the care of CAD patients. At least many of the atypical angina patients could benefit from standard effective treatment for panic disorder. This would likely improve their functioning and decrease the financial burden on them and the health care system.

Adult↗
PubMed1986

New disorder of vitamin B12 metabolism (cobalamin F) presenting as methylmalonic aciduria.

An infant with vitamin B12-responsive methylmalonic aciduria and no homocystinuria or megaloblastic anemia presented with stomatitis, glossitis, convulsions, and developmental delay. Cultured fibroblasts showed defective incorporation of both [14C]5-methyltetrahydrofolate and [14C]propionate into protein by whole cells and a decrease of methionine synthase activity in cell extracts. Despite excessive incorporation of [57Co]cyano-B12 by fibroblasts from the patient, free vitamin B12 was unable to efflux from lysosomes, and, therefore, synthesis of both adenosyl-B12 and methyl-B12 was impaired.

5-Methyltetrahydrofolate-Homocysteine S-Methyltran↗
PubMed1976

[Coronary insufficiency in pheochromocytoma].

The authors report the case of a 42 year old female with a phaeochromocytoma who, in the course of a hypertensive episode, had ECG changes typical of a myocardial infarction. These changes regressed within a few days. A normal coronary arteriogram confirmed the purely functional nature of this episode of acute myocardial ischaemia. In addition to the case report, the authors discuss the physio-pathological and electrocardiographic features of the coronary insufficiency of phaeochromocytoma, and also the problem of the rapide regression of the changes of infarction on the ECG.

Adrenal Gland Neoplasms↗