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Biomedical subjects

J L Laplanche

Publications and source records attributed to J L Laplanche.

At least 19 recordsLinked to original sources
PubMed2006

Spatio-developmental distribution of the prion-like protein doppel in Mammalian testis: a comparative analysis focusing on its presence in the acrosome of spermatids.

The first prion-like protein doppel, officially designed as prion protein dublet, does not seem to be needed for prion disease progression, whereas its physiological function seems to be related to male fertility. Its expression is primarily detected in the male genital tract, and Prnd-inactivated male mice are sterile. We investigated the location of Doppel in the testis of various species of mammal to determine its physiological function. Doppel is expressed early during ontogenesis, and is found in both germ cells and Sertoli cells in mice, rats, boars, and humans. Doppel is permanently expressed in the Sertoli cells but at different levels according to species. Its expression in testicular germ cells was primarily detected in spermatids, with a transient presence in the acrosome. These data suggest that Doppel may play a physiological role in acrosome biogenesis and may be of use in studies of patients suffering from idiopathic infertility.

Acrosome↗
PubMed2004

Dissociation in circadian rhythms in a pseudohypersomnia form of fatal familial insomnia.

The authors present clinical, sleep, and neuroendocrine features of a patient with genetically confirmed fatal familial insomnia (D178N mutation with heterozygosity at codon 129 of the prion protein gene). The patient exhibited pseudohypersomnia behavior instead of insomnia. There was profound alteration in the sleep-wake cycle with a clear dissociation in the disappearance of circadian and neuroendocrine rhythms, findings unrelated to abnormalities in the hypocretinergic system.

Adrenocorticotropic Hormone↗
PubMed2004

Compassionate use of quinacrine in Creutzfeldt-Jakob disease fails to show significant effects.

Quinacrine has been reported as an antiprion agent and proposed as an immediately applicable treatment for Creutzfeldt-Jakob disease (CJD). The authors report the results of an open compassionate procedure to which 32 CJD patients had access. In some genotypic subgroups, a slight but nonsignificant increase in survival was observed, likely due to biased inclusion of long-term surviving patients. There was no pathologic evidence of a beneficial effect of quinacrine treatment.

Brain↗
PubMed2003

[Usefulness of molecular genetic analysis of the PRNP gene in patients with cerebellar ataxia: a new case of fatal familial insomnia].

We report the fifth French case of fatal familial insomnia, characterized by a mutation at codon 178 of prion protein gene and by heterozygoty (Met/Val) at codon 129. The clinical picture included cerebellar ataxia, dysautonomia and frontal lobe syndrome. Prion protein gene analysis was performed in order to support a diagnosis of Creutzfeldt-Jakob disease and assert the diagnosis of fatal familial insomnia. Neuropathologic analysis showed unusual changes including severe neuronal loss in the inferior olive and the dentate nucleus, and absence of obvious lesions in the thalamus. Moreover, spongiform changes were moderate in the superior temporal cortex and the occipital cortex. There was no spongiform change in frontal cortex. Abnormal prion protein (PrP(res)) was mainly evidenced in the parietal cortex. Molecular genetic study of the PRNP gene should be performed in patients who present with a cerebellar ataxia of equivocal origin.

Amyloid↗
PubMed2002

Serotonin transporter gene polymorphisms and hyperserotonemia in autistic disorder.

Previous studies have provided conflicting evidence regarding the association of the serotonin transporter (5-HTT) gene with autism. Two polymorphisms have been identified in the human 5-HTT gene, a VNTR in intron 2 and a functional deletion/insertion in the promoter region (5-HTTLPR) with short and long variants. Positive associations of the 5-HTTLPR polymorphism with autism have been reported by two family-based studies, but one found preferential transmission of the short allele and the other of the long allele. Two subsequent studies failed to find evidence of transmission disequilibrium at the 5-HTTLPR locus. These conflicting results could be due to heterogeneity of clinical samples with regard to serotonin (5-HT) blood levels, which have been found to be elevated in some autistic subjects. Thus, we examined the association of the 5-HTTLPR and VNTR polymorphisms of the 5-HTT gene with autism, and we investigated the relationship between 5-HTT variants and whole-blood 5-HT. The transmission/disequilibrium test (TDT) revealed no linkage disequilibrium at either loci in a sample of 96 families comprising 43 trios and 53 sib pairs. Furthermore, no significant relationship between 5-HT blood levels and 5-HTT gene polymorphisms was found. Our results suggest that the 5-HTT gene is unlikely to play a major role as a susceptibility factor in autism.

Adolescent↗
PubMed2001

Serotonin transporter gene polymorphism and psychiatric disorders in NF1 patients.

Neurofibromatosis type 1 (NF1) is an autosomal-dominant genetic disease characterized by a broad clinical expression. Comorbid affective disorders, anxiety disorders, and suicide are frequently observed during NF1. The promoter marker (5-HTTLPR) of the serotonin transporter gene (5-HTT) has been shown to be associated with major affective disorders, anxiety-related trait, and more recently with suicidal behavior. This gene is adjacent to the NF1 gene, raising the question of the implication of the 5-HTT gene in the psychiatric comorbidity during NF1. Eighty-eight patients with NF1 and 184 screened controls were typed for the 5-HTTLPR. No deviation from the Hardy-Weinberg equilibrium in patients was observed. In addition, allele and genotype frequencies were similar in the two groups. Our data do not support the implication of the 5-HTT gene in the psychiatric comorbidities of NF1.

Alleles↗
PubMed2001

14-3-3 protein cerebrospinal fluid detection in human growth hormone-treated Creutzfeldt-Jakob disease patients.

The usefulness of the detection of 14-3-3 protein in the cerebrospinal fluid (CSF) in the diagnosis of Creutzfeldt-Jakob disease transmitted from human growth hormone was evaluated in 20 French patients. The 14-3-3 protein was rarely detectable within the first 3 months of the disease but always positive after 7 months associated with the aggravation of the disease and the occurrence of dementia. 14-3-3 detection was not predictive of the survival time of the patients. The genotype at PRNP codon 129 could influence the timing of appearance of the 14-3-3 protein in the CSF.

14-3-3 Proteins↗
PubMed2001

Distribution of the M129V polymorphism of the prion protein gene in a Turkish population suggests a high risk for Creutzfeldt-Jakob disease.

A polymorphism (M129V) at codon 129 of the prion protein gene (PRNP) results in either a methionine residue (Met) or a valine residue (Val) and is known to determine susceptibility for the development of sporadic or acquired Creutzfeldt-Jakob disease (CJD). The distributions of M129V genotypes and alleles in various general populations have been reported and there are clear differences between Western Europeans and East Asians. We analysed the coding sequence of the PRNP gene in 100 healthy Turkish subjects to determine whether the distributions of the M129V genotypes and alleles or other PRNP gene variants in the Turkish population differ from those in other normal populations. Three known polymorphisms but no other gene variants were detected in the PRNP coding sequence of the Turkish individuals. Genotype frequencies at codon 129 were 57% Met/Met, 34% Met/Val and 9% Val/Val, with an allele frequency of 0.740:0.260 Met:Val. These distributions are considerably different from those reported for other normal populations residing in Western Europe and East Asia, except in Crete. The higher frequency of 129 Met-homozygotes in Turkey than in Western Europe suggests that the Turkish are at greater risk of developing CJD.

Adult↗
PubMed2000

Dementia with Lewy bodies in a neuropathologic series of suspected Creutzfeldt-Jakob disease.

Discriminating Creutzfeldt-Jakob disease (CJD) from dementia with Lewy bodies (DLB) may be clinically difficult to achieve. The authors describe 10 patients with DLB initially referred to the French Network of Human Spongiform Encephalopathies as having suspected CJD. In a series of 465 autopsied cases, DLB ranked second among degenerative alternative diagnoses to CJD. The authors analyzed the factors that contributed to misleading the diagnosis, and suggest that the detection of 14-3-3 protein in CSF may be useful to distinguish CJD from DLB.

Aged↗
PubMed2000

Analysis of EEG and CSF 14-3-3 proteins as aids to the diagnosis of Creutzfeldt-Jakob disease.

OBJECTIVE: To improve diagnostic criteria for sporadic Creutzfeldt-Jakob disease (CJD). METHODS: Pooled data on initial and final diagnostic classification of suspected CJD patients were accumulated, including results of investigations derived from a coordinated multinational study of CJD. Prospective analysis for a comparison of clinical and neuropathologic diagnoses and evaluation of the sensitivity and specificity of EEG and 14-3-3 CSF immunoassay were conducted. RESULTS: Data on 1,003 patients with suspected CJD were collected using a standard questionnaire. After follow-up was carried out, complete clinical data and neuropathologic diagnoses were available in 805 cases. In these patients, the sensitivity of the detection of periodic sharp wave complexes in the EEG was 66%, with a specificity of 74%. The detection of 14-3-3 proteins in the CSF correlated with the clinical diagnosis in 94% (sensitivity). The specificity (84%) was higher than that of EEG. A combination of both investigations further increased the sensitivity but decreased the specificity. CONCLUSIONS: Incorporation of CSF 14-3-3 analysis in the diagnostic criteria for CJD significantly increases the sensitivity of case definition. Amended diagnostic criteria for CJD are proposed.

14-3-3 Proteins↗
PubMed2000

Signal transduction through prion protein.

The cellular prion protein PrPc is a glycosylphosphatidylinositol-anchored cell-surface protein whose biological function is unclear. We used the murine 1C11 neuronal differentiation model to search for PrPc-dependent signal transduction through antibody-mediated cross-linking. A caveolin-1-dependent coupling of PrPc to the tyrosine kinase Fyn was observed. Clathrin might also contribute to this coupling. The ability of the 1C11 cell line to trigger PrPc-dependent Fyn activation was restricted to its fully differentiated serotonergic or noradrenergic progenies. Moreover, the signaling activity of PrPc occurred mainly at neurites. Thus, PrPc may be a signal transduction protein.

Animals↗
PubMed2000

Possible association between serotonin transporter gene polymorphism and violent suicidal behavior in mood disorders.

BACKGROUND: Genes involved in the serotonin system are major candidates in association studies of suicidal behavior. In this case-control study we investigated whether the serotonin transporter (5-HTT) gene encoding the protein responsible for the reuptake of serotonin from the synapse after its release from serotonergic neurons is a susceptibility factor for suicidal behavior. METHODS: A functional polymorphism of the 5-HTT gene (a 44-base pair insertion/deletion in the 5-HTT-linked polymorphic region [5-HTTLPR]) was studied in a population of 237 consecutive patients with affective disorder (unipolar or bipolar) and 187 control subjects. Ninety-nine patients had attempted suicide at least once, of whom 26 made a violent attempt. RESULTS: No association was found between the "s" allele of the 5-HTTLPR and suicide attempt; however, there was a significant difference in allele distributions between patients who had made violent suicide attempts and control subjects. CONCLUSIONS: A genetic variant of the 5-HTT gene may predispose individuals to violent suicidal behavior. The precise phenotype associated with the 5-HTT gene is unclear, and therefore further studies are required to replicate these findings.

Adult↗
PubMed2000

Novel approaches in diagnosis and therapy of Creutzfeldt-Jakob disease.

The scrapie prion protein, PrP(Sc), as well as its peptide fragment, PrP106-126, are toxic on neuronal cells, resulting in cell death by an apoptotic, rather than necrotic mechanism. The apoptotic process of neuronal cells induced by prion protein supports diagnosis and offers potential targets for therapeutic intervention of the prion diseases. Among the cerebrospinal fluid (CSF) proteins, which may serve as markers of neuronal cell death associated with prion diseases, the 14-3-3 protein(s) turned out to be the most promising one. A new sensitive assay allows the detection of even small changes in the normally low levels of these proteins. In vitro, the toxic effects displayed by PrP(Sc) and its peptide fragment can be blocked by antagonists of N-methyl-D-aspartate (NMDA) receptor channels, like Memantine. Also Flupirtine, a non-opiod analgesic drug, which is already in clinical use, was found to display in vitro a strong cytoprotective effect on neurons treated with PrP(Sc) or PrP106-126. This drug acts like a NMDA receptor antagonists, but does not bind to the receptor. Clinical trials on prion diseases with Flupirtine are in progress. Flupirtine was found to enhance the intracellular levels of the antiapoptotic protein Bcl-2 and the antioxidative agent glutathione (GSH). Due to its favourable pharmacokinetic profile, Flupirtine is considered to be a promising drug to prevent neuronal death in Creutzfeldt-Jakob disease (CJD) and other neurodegenerative disorders occurring with age, e.g. Alzheimer's disease.

Animals↗
PubMed2000

First report of polymorphisms in the prion-like protein gene (PRND): implications for human prion diseases.

The aim of this study was to investigate the possible involvement of genetic variation in the prion-like protein gene (PRND), which encodes the doppel protein (Dpl), in the aetiology of human prion diseases. Patients with sporadic, infectious or genetic forms of human prion diseases and controls were systematically screened, using the single-strand conformational polymorphism method, for genetic variants of the PRND gene. Four polymorphisms in PRND (three structural changes, T26M, P56L and T174M and a silent polymorphism, T(174)T) were detected. No strong association was found between any of these polymorphisms and human prion diseases but certain PRND alleles may be useful markers for tracing the chromosomal ancestry of PRNP mutations. Although genetic variation in PRND does not seem to play a major role in the pathogenesis of prion diseases, this first report of PRND polymorphisms may open up new possibilities for investigating the involvement of such polymorphisms in other human diseases.

Alleles↗
PubMed2000

Functional expression of P-glycoprotein and multidrug resistance-associated protein (Mrp1) in primary cultures of rat astrocytes.

Although it has been well established that the drug efflux pump P-glycoprotein (P-gp) protects the brain against the entry of cytotoxic drugs, its real in situ localization, i.e., at brain capillary endothelial cells or on astrocyte foot processes, is still controversial. The aim of this study was to compare the expression of P-gp and of multidrug resistance-associated protein (Mrp1), another drug efflux pump, in cultured neonatal rat brain astrocytes and in cultured brain capillary endothelial cells. Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis showed that the mdr1b gene was preferentially expressed in astrocytes, whereas both mdr1a and mdr1b mRNA were detected in endothelial cells. Moreover, the mrp1 gene encoding Mrp1 was expressed in both cell types. Western blotting analysis revealed higher expression of P-gp in endothelial cells as compared with astrocytes, but higher expression of Mrp1 in astrocytes. Moreover, P-gp and Mrp1 expression was not modified in more differentiated astrocytes obtained when cultured with db-cAMP for 48 hr. Our functional analysis of P-gp showed a modest effect of P-gp modulators (CsA, verapamil, PSC 833) on the uptake of colchicine (a substrate of P-gp) by astrocytes, whereas they increased by about 50% the uptake of vincristine (a common substrate of P-gp and MRP) by astrocytes. MRP modulators (genistein, probenecid, and sulfinpyrazone) did not modify the uptake of colchicine but increased that of vincristine with a major effect found for sulfinpyrazone. Moreover, indomethacin, probenecid, and sulfinpyrazone increased the uptake of fluorescein (a substrate of MRP but not of P-gp). Taken together, our results provide the first biochemical and functional evidence supporting the expression of P-gp and Mrp1 in rat cultured astrocytes.

ATP Binding Cassette Transporter, Subfamily B, Mem↗