Psychosis in Epilepsy Patients

Introduction

Psychosis in patients with epilepsy was known in antiquity and was already described in detail in the nineteenth century.

This kind of psychosis can be categorized in relations to seizures: preictal psychosis (before the seizures), during them (ictal) or after the seizures (postictal psychosis)

Aims

Through several cases of patients that were treated in our department with the diagnosis of psychosis, previously or during the treatment diagnosed with epilepsy, we analyse the characteristics and diagnostic criteria of these pathologies.

Methods

Systematic literature review in up-to-date and Pubmed, looking for reviews on psychosis and epilepsy, in international scientific journals of neurology and psychiatry.

Conclusions

Being able to recognize this several types of psychotic states associated with epilepsy has a clinic and prognosis utility, because made important differences in treatment and in the evolution of the illness.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Schwann cell precursors transplanted into the injured spinal cord multiply, integrate and are permissive for axon growth

There is a strong current interest in the use of cell transplantation for the treatment of spinal cord injuries. We report here the novel and potentially useful properties of an early cell in the Schwann cell lineage, the Schwann cell precursor (SCP). The experiments reveal a striking difference between these cells and Schwann cells when transplanted into the CNS. Unlike Schwann cells, SCPs thrive in the CNS where they initially proliferate rapidly but then fall out of division, thus effectively filling up the large cystic cavities formed following crush injury, while avoiding tumor formation. By 8 weeks, SCPs had started to express S100beta protein, a marker that differentiates Schwann cells from SCPs and had formed an apparently stable, vascularized cell mass, which created a continuous cellular bridge across the cystic cavities. The formation of the surrounding glial scar was reduced by local spread of the transplanted cells into the surrounding CNS tissue, where the cells integrated intimately with astrocytes and attenuated the physical barrier they normally form. SCP transplantation also altered and reduced the expression of chondroitin sulfate proteoglycans around the injury site. Caudal to the SCP transplants there was a large increase in the number of axons, compared with that seen in nontransplanted control tissue, showing that the implants effectively support axonal growth or sprouting. SCPs have advantageous attributes for CNS repair, despite the fact that sticky tape removal and ladder crossing tests at 8 weeks did not reveal significant functional improvements when compared with control animals.

Semaphorin 3C preserves survival and induces neuritogenesis of cerebellar granule neurons in culture

Semaphorins (sema) constitute a family of molecules sharing a common extracellular domain (semaphorin domain). This family includes several types of secreted and membrane-associated molecules that are grouped into eight subclasses (subclasses 1-7 and viral semaphorins). Subclass 3 semaphorins are secreted molecules involved in axonal guidance, mainly through repulsive gradients and induction of growth cone collapse. More recently sema 3 molecules have been identified as positive factors in dependence of the type of neurons. Besides their axonal guidance function, some semaphorins have been implicated in apoptosis and survival. We investigated the effect of sema3C on survival and neurite outgrowth of rat cerebellar granule neurons (CGNs) in culture. 3T3 cells were stably transfected with sema3C. Several clonal lines were established and tested for their neuritogenic activity and one, S3C-8, was selected for the bulk of experiments. S3C-8 was co-cultured with CGNs. Sema3C enhanced CGN viability as assessed in co-cultures of CGNs with monolayers of S3C-8 in comparison with co-cultures of CGNs with control mock-transfected 3T3 cells. Moreover sema3C induced neuritogenesis of cultured CGNs, which express neuropilin-1 and -2. S3C-8 cells, overexpressing sema3C, were significantly more neuritogenic for CGN than poly l-lysine (PLL), a positive substrate for CGNs, as assessed by the measurement of the length of neurites and confirmed by Tau expression along the time of culture. CGNs co-cultured with S3C-8, showed up-regulation of the expression of axonal microtubule-associated proteins (MAPs) such as Tau, phosphorylated MAP2C and mode I-phosphorylated MAP1B compared with neurons cultured on control 3T3 cells. We also found increased expression of a specific marker of neuronal cell bodies and dendrites, high molecular weight MAP2 (HMW-MAP2). Interestingly, there was no accompanying up-regulation of a marker enriched within the neuronal somatodendritic domain, mode II-phosphorylated MAP1B. These data support the idea that secreted sema3C favors survival and neuritogenesis of cultured CGNs.

Pericentromeric regions containing 1.688 satellite DNA sequences show anti-kinetochore antibody staining in prometaphase chromosomes of Drosophila melanogaster

A striking characteristic of the centromeric heterochromatin of Drosophila melanogaster is that each chromosome carries different satellite DNA sequences. Here we show that while the major component of the 1.688 satellite DNA family expands across the centromere of the X chromosome the rest of the minor variants are located at pericentromeric positions in the large autosomes. Immunostaining of prometaphase chromosomes with the kinetocore-specific anti-BUB1 antibody reveals the transient presence of this centromeric protein in all the regions containing the 1.688 satellite.

A dicentric chromosome of Drosophila melanogaster showing alternate centromere inactivation

Dicentric chromosomes are rarely found, because they interfere with normal cell division causing chromosome instability. By in situ hybridization of region-specific heterochromatic yeast artificial chromosomes we have found that the artificially generated C(1)A chromosome of Drosophila melanogaster has two potential centromeres: one carries all the sequences of the centromere of the Y chromosome and the other carries only a part of the Y centromeric region that is rich in telomere-related sequences. Immunostaining with anti-Bub1 (a kinetochore-specific marker) shows that, in spite of the differences in sequence, both centromeres can be active although as a rule only one at a time. In a small fraction of the chromosomes centromere inactivation is incomplete, giving rise to true dicentric chromosomes. The centromere inactivation is clonally inherited, providing a new example of epigenetic chromosome imprinting and the possibility of genetically dissecting this process. The involvement of telomere-related sequences in centromere function is discussed.

Characterization of a second member of the subfamily of calcium-binding mitochondrial carriers expressed in human non-excitable tissues

We have recently identified a subfamily of mitochondrial carriers that bind calcium, and cloned ARALAR1, a member of this subfamily expressed in human muscle and brain. We have now cloned a second human ARALAR gene (ARALAR2) coding for a protein 78.3% identical to Aralar1, but expressed in liver and non-excitable tissues. Aralar2 is identical to citrin, the product of the gene mutated in type-II citrullinaemia [Kobayashi, Sinasac, Iijima, Boright, Begum, Lee, Yasuda, Ikeda, Hirano, Terazono et al. (1999) Nat. Genet. 22, 159-163]. A related protein, DmAralar, 69% identical to Aralar1, was found in Drosophila melanogaster, the DMARALAR locus lying on the right arm of the third chromosome, band 99F. The N-terminal half of Aralar2/citrin is able to bind calcium and this requires the presence of the two most distal EF-hands. The localization of Aralar2/citrin expressed in human cell lines is mitochondrial, the C-terminal half containing sufficient information for import and assembly into mitochondria. The C-terminal half of Aralar proteins is related to the yeast YPR020c gene, with a very high sequence conservation (54.3% identity), suggesting that these proteins play an important role. Thus Aralar proteins are probably expressed in all tissues in an isoform-specific fashion, where they function as calcium-regulated metabolite (possibly anionic) carriers.

Polypeptides differentially expressed in imaginal discs define the peroxiredoxin family of genes in Drosophila

2D gel electrophoresis followed by microsequencing has been used to purify and identify a protein (catalogued in the database as SSP5111) from Drosophila wing imaginal discs of third instar larvae that showed significant differences in their level of expression when compared with other imaginal discs of the same age. The microsequence data showed identity with amino acids encoded by the human proliferation association gene, pag, which is a thiol-specific antioxidant. By virtue of this homology we have cloned and sequenced two cDNAs that appear to define the peroxiredoxin family of Drosophila. One of them, Jafrac1, encodes the SSP5111 protein searched, had 194 amino acids and mapped in the region 11E in the X chromosome. The other, Jafrac2, encodes a protein of 242 amino acids and mapped in the region 62F in the 3 L chromosome. Both new peroxidases contain two conserved cysteines and share homology with other peroxidases that extends over the entire sequence and ranges between 47% and 76%. An antiserum raised against the SSP5111 protein showed significant changes in the amount of protein in different stages of Drosophila development, being a major product in early embryos. In 2D gels the antibody not only recognizes the SSP5111 polypeptide but also a related one (catalogued in the database as SSP6107) that exhibits identical amino-acid sequence over at least 85% of its sequence. The data also suggest that the SSP5111 polypeptide could be a maternal-effect product.

HeT-A telomere-specific retrotransposons in the centric heterochromatin of Drosophila melanogaster chromosome 3

We have isolated two yeast artificial chromosome (YAC) clones from Drosophila melanogaster that contain a small amount of dodeca satellite (a satellite DNA located in the centromeric region of chromosome 3) and sequences homologous to the telomeric retro-transposon HeT-A. Using these YACs as probes for fluorescence in situ hybridization to mitotic chromosomes, we have localized these HeT-A elements to the centric heterochromatin of chromosome 3, at region h55. The possible origin of these telomeric elements in a centromeric position is discussed.

The analysis of Circe, an LTR retrotransposon of Drosophila melanogaster, suggests that an insertion of non-LTR retrotransposons into LTR elements can create chimeric retroelements

Circe is a transposable element recently identified in Drosophila melanogaster which appears to be mostly associated with the constitutive heterochromatin. This element shows the structural features of a long terminal repeat (LTR)-containing retrotransposon: It is flanked by 240-bp-long terminal repeats, and its two open reading frames encode putative proteins resembling the gag and pol polyproteins of retroviruses. However, Circe displays striking similarities of both LOA and Ulysses, a non-LTR element and an LTR element, respectively. The result of its phylogenetic and structural analysis has allowed us to propose a new mechanism for non-LTR retrotransposon evolution.

Centromeres from telomeres? The centromeric region of the Y chromosome of Drosophila melanogaster contains a tandem array of telomeric HeT-A- and TART-related sequences

Cytological and cytogenetic studies have previously defined the region needed for centromeric function in the Y chromosome of Drosophila melanogaster. We have identified a YAC clone that originated from this region. Molecular analysis of the YAC and genomic DNAs has allowed the description of a satellite DNA made of telomeric HeT-A- and TART-derived sequences and the construction of a long-range physical map of the heterochromatic region h18. Sequences within the YAC clone are conserved in the centromeric region of the sibling species Drosophila simulans. That telomere-derived DNA now forms part of the centromeric region of the Y chromosome could indicate a telomeric origin of this centromere. The existence of common determinants for the function of both centromeres and telomeres is discussed.

Isolation and characterization of the cDNA and the gene for eukaryotic translation initiation factor 4G from Drosophila melanogaster

Recent evidence supports the notion that the eukaryotic polypeptide chain initiation factor (eIF)4G plays a critical bridging role in coordinating other eIF involved in eukaryotic translation initiation. Here we report the isolation and characterization of a 5621-bp cDNA encoding Drosophila eIF4G. The longest ORF predicts a polypeptide of 1666 amino acids with a molecular mass of 183,940 Da and shares 25% amino acid identity with other eIF4G. The 5' untranslated region is 386 nucleotides long and contains seven AUG codons out of frame. The in vitro transcription/translation of the cDNA yielded a major polypeptide, which was specifically immunoprecipitated with an antibody against Drosophila eIF4G. This polypeptide has the same electrophoretic mobility as eIF4G purified from Drosophila melanogaster embryos. A conserved eIF4E-binding motif was found in Drosophila eIF4G. The gene maps at the 102E region of chromosome 4 and spans a genomic region of approximately 16 kb. It was found to contain 15 introns. A single RNA transcript of approximately 5.9 kb was detected by northern blotting of poly(A)-rich RNA prepared from Drosophila adults. The sequence upstream of the transcription initiation site lacks the consensus TATA box, but contains several sequences possibly involved in the regulation of transcription.

A proposal for the establishment of the National Center for Phytogenetic Resource Conservation in the Venezuelan Republic

The conservation of biodiversity, a valuable natural resource, is considered essential. In the face of continued threats to this resource the establishment of a National Center for Phytogenetic Resource Conservation in Venezuela is proposed. The proposed center would have the following main objectives: inventory of resources, establishment of a plant gene bank, basic ecological research, promotion of cultivation of useful but endangered species, promotion of national and international information-exchange, and protection of natural habitats. The organizational structure of the proposed center is outlined.