PubMed Health⌕ Search

Biomedical subjects

A Malafosse

Publications and source records attributed to A Malafosse.

At least 55 records · Page 3Linked to original sources
PubMed1998

Genetic variation in EEG activity during sleep in inbred mice.

The genetic variation in spontaneous rhythmic electroencephalographic (EEG) activity was assessed by the quantitative analysis of the EEG in six inbred mice strains. Mean spectral EEG profiles (0-25 Hz) over 24 h were obtained for paradoxical sleep (PS), slow-wave sleep (SWS), and wakefulness. A highly significant genotype-specific variation was found for theta peak frequency during both PS and SWS, which strongly suggests the presence of a gene with a major effect. The strain distribution of theta peak frequency during exploratory behavior differed from that during sleep. In SWS, the relative contributions of delta (1-4 Hz) and sigma (11-15) power to the EEG varied with genotype and power in both frequency bands was negatively correlated. In addition, the EEG dynamics at state transitions were analyzed with a 4-s resolution. The onset of PS, but not that of wakefulness, was preceded by a pronounced peak in high-frequency (>11 Hz) power. These findings are discussed in terms of the neurophysiological mechanisms underlying rhythm generation and their control and modulation by the brain stem reticular-activating system.

Animals↗
PubMed1998

[Unverricht-Lündborg disease: clinical and electrophysiologic study of 19 Maghreb families].

We describe clinical, electrophysiological and genetic features in 44 patients with Unverricht-Lündborg disease from 19 families living in North African countries (Tunisia, Algeria and Morocco). The mean age of patients was 25.3 years; mean age was at onset 11.3 years. The disease began more frequently with seizures (91 per cent) or myoclonus (80 p. 100) than ataxia (16 p. 100). Subsequently myoclonus and generalized seizures were present in all patients, cerebellar signs were absent in four cases. EEG findings included normal background activity (90 p. 100), spontaneous fast generalized spikes (93 p. 100) and photosensitivity (70 p. 100). Antiepileptic polytherapy (clonazepam and/or phenobarbital and/or valporic acid) was used in 84 per cent of cases. Antiepileptic drugs were more effective in controlling epileptic seizures (less than one seizure/month in 60 p. 100) than myocloni which persisted daily in 64 p. 100 of cases. Mean duration of the disease was 13.5 years. One patient died of status epilepticus. Consanguinity was noted in 17 families (first degree in 15 families). Linkage to chromosome 21q 22.3 was confirmed in 11 families. We noted an inter and intrafamilial variability of clinical signs and disease course.

Adolescent↗
PubMed1997

Localization of candidate genomic regions influencing paradoxical sleep in mice.

Quantitative trait loci (QTL) approach was used in CXB recombinant inbred mice for preliminary identification of candidate regions on the mouse genome that influence sleep. The only provisional QTLs identified were associated with paradoxical sleep (PS). PS during the light period was associated with markers on chromosome 7 between 7 and 20 centimorgan from the centromere. For PS during the dark period, a single QTL was identified on chromosome 5, near the Clock gene. The 24 h amount of PS was influenced by markers on chromosomes 2, 17, and 19. This first QTL mapping study strongly suggests that a complex behaviour like PS can be controlled by only a few genes.

Animals↗
PubMed1997

Dodecamer repeat expansion in cystatin B gene in progressive myoclonus epilepsy.

Progressive myoclonus epilepsy of the Unverricht-Lundborg type (EPM1; MIM 254800) is an autosomal recessive disorder with onset between 6 and 13 years followed by variable progression to mental deterioration and cerebellar ataxia. It is a rare disorder but more common in Finland (1 in 20,000) and the western Mediterranean. Two point mutations in the cysteine proteinase inhibitor gene cystatin B (CSTB), proved that this gene is responsible for EPM1 (ref. 3). An extensive search in the CSTB gene revealed mutations accounting only for 14% of the 58 unrelated EPM1 alleles studied. Here we report that the majority of EPM1 alleles contain expansions of a dodecamer (12-mer) repeat located about 70 nucleotides upstream of the transcription start site nearest to the 5' end of the CSTB gene. Normal alleles contain 2 or 3 copies of this repeat whereas mutant alleles contain more than 60 such repeats and have reduced levels of CSTB messenger RNA in blood but not in cell lines. 'Premutation' CSTB alleles with 12-17 repeats show marked instability when transmitted to offspring.

Alleles↗
PubMed1997

Lack of association between juvenile myoclonic epilepsy and GABRA5 and GABRB3 genes.

Alpha 5 and beta 3 GABAA receptor genes are major candidates for epilepsy, as they code for subunits of the most important human inhibitory neurotransmitter. Moreover, they are located within a region of the human genome previously implicated in disorders including epilepsy. We carried out an association study between dinucleotide repeat polymorphisms in these two genes and juvenile myoclonic epilepsy (JME). JME is the most common idiopathic epilepsy and is characterized by a complex mode of inheritance. We did not find significant differences between controls and patients for allele or genotype frequencies.

Adult↗
PubMed1997

Allelic heterogeneity of Mediterranean myoclonus and the cystatin B gene.

Mediterranean myoclonus is a progressive myoclonus epilepsy with autosomal recessive inheritance. Another form has been described in Finland, the so-called Baltic myoclonus. Mediterranean myoclonus and Baltic myoclonus are also known as Unverricht-Lundborg disease. Linkage analyses have shown that the genes for both these forms of myoclonus are closely linked to 21q22.3 DNA markers, suggesting that they are caused by mutations at the same locus (EPM1). Recently, two heterozygous mutations were found in the cystatin B gene in patients with Unverricht-Lundborg disease. We report recombinational and linkage disequilibrium mapping of EPM1, and cystatin B gene sequencing, in 14 consanguineous pedigrees with Mediterranean myoclonus. Linkage to 21q22.3 DNA markers was observed in all these families. Haplotype analysis suggests that a common mutation segregates within these pedigrees, and that this mutation is different from the common one responsible for the Finnish form of Unverricht-Lundborg disease. No mutation was found in the exons or splice junctions of the cystatin B gene in the 14 pedigrees.

Base Sequence↗
PubMed1997

Manic depressive illness and tyrosine hydroxylase gene: linkage heterogeneity and association.

Several studies have implicated the tyrosine hydroxylase (TH) locus within the 11p15 region in susceptibility to manic depressive illness (MDI). This possibility was further investigated by both parametric (lod score) and nonparametric (affected-pedigree-member and a case-control study) methods of analysis in 11 French MDI families and in a sample of 200 unrelated subjects. Both types of analyses corroborate the implication of this locus, and positive lod scores were obtained in two families, which most likely reflects genetic heterogeneity. Statistical analyses were also performed including available data from published reports. These analyses, which allowed for genetic heterogeneity, substantiated our findings. The combined maximum lod score for all the families studied was 3.68 at theta = 0.00 (number of families: 36) assuming heterogeneity (alpha = 15%, P = 0.01). Taken together these results converge to suggest that the risk factors for MDI lie in the 11p15 region with TH being the most likely candidate gene.

Alleles↗
PubMed1997

Linkage mapping of benign familial infantile convulsions (BFIC) to chromosome 19q.

Benign familial infantile convulsions (BFIC) are an autosomal-dominant epileptic syndrome characterized by an age of onset within the first year of life. Although they were first reported in families of Italian descent, BFIC have also been described in non-Italian families. We have mapped the BFIC gene to chromosome 19 by linkage analysis in five Italian families with a maximum two-point lod score of 6.36 at D19S114; maximum multipoint lod scores > 8 were obtained for the interval D19S250-D19S245. BFIC are therefore the third idiopathic partial epileptic syndrome to be mapped on the human genome.

Chromosome Mapping↗
PubMed1997

Weak association between blood sodium, potassium, and calcium and intensity of symptoms in major depressed patients.

In previous reports, we showed that plasma and erythrocyte magnesium were increased in many drug-free hospitalized depressed patients. Furthermore, we observed that erythrocyte magnesium content was related to the intensity of the symptoms. Highly depressed patients had the highest magnesium values. Today, we report the results of plasma and erythrocyte sodium and potassium, and of total and ultrafilterable plasma calcium in 66 hospitalized patients with major depression compared to 58 healthy controls. No consistent differences in these biochemical parameters are observed between patients when separated according to intensity of anxiety, psychomotor retardation, and moral distress. Plasma sodium is higher and plasma potassium lower in female patients of all subgroups as compared to controls. Both male patients and controls have erythrocyte sodium and potassium levels that are significantly different from those of females. This clearly suggests a separation into genders in such studies. In conclusion--in contrast to blood magnesium--sodium, potassium, and calcium levels do not seem to be related to the intensity of the main clinical symptoms in hospitalized patients with major depression.

Adult↗
PubMed1997

Identification of mutations in cystatin B, the gene responsible for the Unverricht-Lundborg type of progressive myoclonus epilepsy (EPM1).

Progressive myoclonus epilepsy (EPM1) is an autosomal recessive disorder, characterized by severe, stimulus-sensitive myoclonus and tonic-clonic seizures. The EPM1 locus was mapped to within 0.3 cM from PFKL in chromosome 21q22.3. The gene for the proteinase inhibitor cystatin B was recently localized in the EPM1 critical region, and mutations were identified in two EPM1 families. We have identified six nucleotide changes in the cystatin B gene of non-Finnish EPM1 families from northern Africa and Europe. The 426G-->C change in exon 1 results in a Gly4Arg substitution and is the first missense mutation described that is associated with EPM1. Molecular modeling predicts that this substitution severely affects the contact of cystatin B with papain. Mutations in the invariant AG dinucleotides of the acceptor sites of introns 1 and 2 probably result in abnormal splicing. A deletion of two nucleotides in exon 3 produces a frameshift and truncates the protein. Therefore, these four mutations are all predicted to impair the production of functional protein. These mutations were found in 7 of the 29 unrelated EPM1 patients analyzed, in homozygosity in 1, and in heterozygosity in the others. The remaining two sequence changes, 431G-->T and 2575A-->G, probably represent polymorphic variants. In addition, a tandem repeat in the 5' UTR (CCCCGCCCCGCG) is present two or three times in normal alleles. It is peculiar that in the majority of patients no mutations exist within the exons and splice sites of the cystatin B gene.

Amino Acid Sequence↗
PubMed1997

[Clinical study of familial forms of amyotrophic lateral sclerosis. Review of the literature].

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder involving both upper and lower motor neurons. The disease is possibly due to several factors, including a genetic one. This is supported by the existence of 5 to 10 p. 100 familial cases. In these pedigrees, the transmission is autosomal dominant, with a high penetrance (> 90 p. 100). We studied the phenotypes of these familial cases, in reviewing the literature on familial ALS (FALS). It has been noted that FALS are heterogeneous, with different age of onset, site of onset and disease duration. Moreover, in FALS, onset is earlier than in the sporadic form (48 vs 60 years, as usually reported in the literature). We also frequently noted sensory disorders (20 p. 100), onset on the lower limbs (46 p. 100) and decreased or absent ankle-jerks (75 p. 100) in FALS patients.

Age Factors↗
PubMed1996

Apolipoprotein E genotyping in sporadic amyotrophic lateral sclerosis: evidence for a major influence on the clinical presentation and prognosis.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative motor neuron disorder of unknown etiology. Recently, in Alzheimer's disease (AD) apolipoprotein E (APOE) alleles have been shown to play an important role in disease phenotype. To determine whether APOE have a similar influence in other neurodegenerative disorders, we studied APOE genotypes in 130 sporadic ALS patients, compared with controls. We also analyzed APOE genotypes regarding ALS clinical criteria. The frequency of APOE genotypes was not different between ALS and controls. However, subjects with the APOE2/E3 genotype showed a significantly longer duration of the disease: 51 months vs. 28.5 for APOE3/E3 and 27.5 for APOE3/E4 (p = 0.001 and p = 0.02, respectively). There was a significantly higher proportion of bulbar ALS patients in the APOE3/E4 group (72% of the cases), whereas 90% of patients in the APOE2/E3 group showed limb onset (p = 0.01). In the bulbar group, patients with APOE4 showed earlier onset of the disease: 60 vs. 66 years (mean age, p = 0.05). These results are consistent with a protective role of APOE2 and a deleterious role of APOE4 in ALS as already found for AD. This parallel supports the idea of a general role of APOE in neuronal degeneration or regeneration rather than a specific role in ALS or AD etiopathogenesis.

Age of Onset↗
PubMed1996

[Epidemiologic and molecular genetic of suicidal behavior].

The current understanding of suicidal behaviors is that such behaviors are multidetermined and mental state and trait related. Genetic factors appear to be of great importance, as suggested by the findings of family, twin, and adoption studies. Whether these genetic factors are similar to those involved in the susceptibility to psychiatric disorders closely related to suicidal behavior (eg, manic depressive illness, schizophrenia or substance use disorders) is yet unknown. However, a genetic factor of susceptibility to suicide, independent or additive to the genetic transmission of the psychiatric disorders that are related to suicidal behavior, is strongly suggested by the data of the Copenhagen adoption study and a study of Amish families. Recently, new approaches have been proposed to identify the genetic component of such complex traits. Association studies between genetic markers and a disease phenotype has been successfully applied to several complex disease such as essential hypertension. One candidate gene for suicidal behaviors is the tryptophane hydroxylase (TPH) gene which is the first and possibly rate-limiting enzyme of the metabolic pathway for serotonin. Indeed, altered serotoninergic function in both completed suicide and suicide attempt has been one of the most replicated findings in modern biological psychiatry. In our knowledge, only two studies have tested the association between suicide attempt and the TPH gene and their authors found negative results. Despite these negative results, association studies that use candidate gene remain one of the methods of choice for studying the genetic component of suicidal behaviors.

Depressive Disorder↗
PubMed1995

Suicidal behaviors and the tryptophan hydroxylase gene.

BACKGROUND: To determine whether the tryptophan hydroxylase gene (ie, the gene that codes for the rate-limiting enzyme in the metabolic pathway of serotonin) may be a susceptibility factor for suicidal behavior. METHODS: Genotypic and allelic frequencies at a polymorphic Ava II restriction site were revealed with the use of the complementary DNA tryptophan hydroxylase probe C2-38 in 62 suicide attempters. The psychiatric characteristics of these suicide attempters were determined using the Schedule for Affective Disorders and Schizophrenia-Lifetime version with modification for the study of anxiety disorders, and these characteristics were compared with those in 52 healthy controls. RESULTS: No association between tryptophan hydroxylase and suicidal behavior was detected. CONCLUSION: The tryptophan hydroxylase gene was not a susceptibility factor for suicidal behaviors in the group of suicide attempters in this study.

Alleles↗
PubMed1994

Benign infantile familial convulsions are not an allelic form of the benign familial neonatal convulsions gene.

Benign infantile familial convulsions (BIFC) and benign familial neonatal convulsions (BFNC) are two forms of familial convulsions having an age of onset within the first year of life. The gene responsible for BFNC has been mapped to chromosome 20q in the close vicinity of D20S19 and D20S20 markers. We performed linkage analysis between BIFC and D20S19-D20S20 in eight families in order to know whether the BFNC gene is also implicated in BIFC. Several apparent obligate crossovers between affected members were detected. The data here presented demonstrate that the BFNC gene is not responsible for BIFC.

Age of Onset↗
PubMed1994

A nonsense mutation in the alpha4 subunit of the nicotinic acetylcholine receptor (CHRNA4) cosegregates with 20q-linked benign neonatal familial convulsions (EBNI)

Benign Familial Neonatal Convulsions (BFNC) is an epileptic disorder with an autosomal dominant mode of transmission. It has been shown that about 80% of BFNC pedigrees are linked to a genetic defect on chromosome 20q13.3. A candidate gene for the epilepsies, the gene coding for the alpha4 subunit of the nicotinic cholinergic receptor (CHRNA4), has previously been localized on chromosome 20. Here we report a single point mutation converting a serine codon to a stop codon in the exon 5 of CHRNA4, in one BFNC family. Identification of CHRNA4 as the defective gene in 20q-BFNC represents the first example of a human idiopathic epilepsy caused by a mutation directly affecting a neurotransmitter receptor in the central nervous system.

DNA Probes↗