[Autism spectrum disorder. Contemporary experimental researches review].

Autism, like schizophrenia, are heterogeneous diseases, which are directed by both genetic factors and external influences in the early stages of development. Knowledge about the similarities and differences of these disorders can help early diagnosis and treatment. Patients with autism have specific cognitive difficulties in social relations.

[EEG synchronisation in autistic children. Analysis of coherency].

EEG study of 5-7 years boys with autism revealed lower values of coherence in background delta, theta and alpha bands and higher values of coherence in background beta 1, beta 2 and gamma bands. Healthy boys showed higher values of beta and gamma coherence during cognitive task. Autistic persons demonstrated higher values of theta coherence during cognitive task.

Expression of beta-secretase mRNA in transgenic Tg2576 mouse brain with Alzheimer plaque pathology.

On the basis of the recent cloning of the beta-secretase, the beta-site amyloid precursor protein (APP)-cleaving enzyme (BACE), (Science, 286 (1999) 735), digoxigenin-labelled riboprobes were generated to localize the cellular expression pattern of BACE mRNA in brain sections of transgenic Tg2576 mice, overexpressing the Swedish mutation of the APP695 isoform. Non-radioactive in situ hybridization in combination with immunohistochemistry to identify the cell types and beta-amyloid deposits revealed strong BACE mRNA hybridization signals in neurons of the cerebral cortex, hippocampal formation, thalamus and cholinergic basal forebrain nuclei, while astrocytes did not display any labeling. Neurons surrounding beta-amyloid deposits did not demonstrate altered expression level of BACE mRNA as compared to neurons in cortical areas that are free of beta-amyloid deposits, and the regional expression pattern of BACE mRNA did not correlate with the distribution of beta-amyloid deposits.

Long-term basal forebrain cholinergic-rich grafts derived from trisomy 16 mice do not develop beta-amyloid pathology and neurodegeneration but demonstrate neuroinflammatory responses.

Patients with Down syndrome (human trisomy 21) develop neuropathological and cholinergic functional defects characteristic of Alzheimer's disease, which has been attributed to the location of the Alzheimer beta-amyloid precursor protein on chromosome 21. Due to the partial genetic homology between mouse chromosome 16 and human chromosome 21, murine trisomy 16 was used as a model to study functional links between increased expression of the amyloid precursor protein, neurodegeneration and neuroinflammatory responses. Basal forebrain cholinergic-rich tissue derived from trisomy 16 mice at embryonic age of day 16 was transplanted into the lateral ventricle of adult normal mice.