Adult attention-deficit hyperactivity disorder is associated with alterations in circadian rhythms at the behavioural, endocrine and molecular levels.

Attention-deficit hyperactivity disorder (ADHD) in adults is associated with impaired sleep, and it has been postulated that this impairment may contribute to the psychopathology of this common condition. One key driver of sleep/wake cycles is the circadian system, which at the molecular level consists of a series of transcriptional feedback loops of clock genes, which in turn produce endocrine, physiological and behavioural outputs with a near 24 h periodicity. We set out to examine circadian rhythms at the behavioural, endocrine and molecular levels in ADHD. Adults with ADHD as well as age- and sex-matched controls were recruited. Circadian rhythms were measured by means of actigraphy for the determination of gross motor patterns, by self-sampling of oral mucosa for assessment of rhythmic expression of the clock genes BMAL1 and PER2, and by estimation of salivary cortisol and melatonin levels. Actigraphic analysis revealed significant diurnal and nocturnal hyperactivity in the ADHD group, as well as a significant shorter period of best fit for the locomotor circadian rhythm in ADHD. BMAL1 and PER2 showed circadian rhythmicity in controls with this being lost in the ADHD group. Cortisol rhythms were significantly phase delayed in the ADHD group. These findings indicate that adult ADHD is accompanied by significant changes in the circadian system, which in turn may lead to decreased sleep duration and quality in the condition. Further, modulation of circadian rhythms may represent a novel therapeutic avenue in the management of ADHD.

Upregulating CD59: a new strategy for protection of neurons from complement-mediated degeneration.

An increasing number of studies have shown a critical role for the membrane attack complex, synthesized on activation of the terminal pathway of the complement system, in causing demyelination and neuronal death in neurodegeneration. The aim of this study was to develop a strategy to increase the resistance of neurons to complement damage by modulating the expression of membrane complement regulatory protein CD59, the only inhibitor of the terminal pathway of the complement cascade. We exploited our recent finding that CD59 expression is regulated by the neural-restrictive silencer factor (REST) and designed a novel REST-derived peptide (REST5) containing the nuclear localization domain of the wild-type protein. The effect of REST5 and the mechanism by which it modulates CD59 expression were modelled in neuroblastoma cells transfected with expression constructs, and then confirmed in human neurons differentiated from neural progenitor cells. REST5 increased the expression of CD59 in neurons by fivefold and protected them from complement-mediated lysis spontaneously triggered by neurons. As a source of complement, we used either human serum or conditioned medium from primary human oligodendroglia. This study brings new insight into immunopharmacological research that may serve to inhibit neuronal death triggered by the terminal pathway of complement activation.

Macromolecular and ultrastructural organization of the mitotic chromosome scaffold.

Using electron microscopy (EM), we have examined three structural domains of the mitotic chromosome scaffold of mouse erythroleukemia (MEL) Friend cells with different morphologic organization: centromeric, intermediate, and telomeric. The intermediate, most extensive, domain exhibited a specific fibrogranular structure representing tightly packed granular bodies with diameters between 20 and 60 nm. The chromosome scaffold contained three main components: proteins (81%), RNA (12%), and DNA (7%). The residual DNA extracted from the scaffold represented short fragments, 300 bp on average, belonging to the class of tandemly arranged repetitive DNA. In situ hybridization experiments confirmed its typical centromeric location. Scaffold RNA represented three fractions: a major RNA fraction with an electrophoretic mobility corresponding to that of 5S RNA and two minor fractions with electrophoretic mobilities somewhat lower than that of 18S RNA. Scaffold RNA was localized mainly in the centromeric region. We show that the newly synthesized protein component of the chromosome scaffolds migrates slowly to the chromosomes, reaching a maximum specific radioactivity 12 h from the onset of the chase period.

Localisation of DNA topoisomerase IIalpha in mouse erythroleukemia cells.

The presence of DNA topoisomerase IIalpha was investigated in interphase and metaphase mouse erythroleukemia (MEL) Friend-S cells, and in extracted with 25 mM lithium diiodosalicylate buffer (Lis) nuclei using indirect immunofluorescence. The results showed that DNA topoisomerase IIalpha is localised in the nuclei. In the metaphase cells, we found high concentrations of this enzyme in the mitotic chromosomes. Our results support the idea of the accumulation of DNA topoisomerase IIalpha at the end of the cell cycle. The extractions of nuclei with 25 mM Lis led to the complete depletion of DNA topoisomerase IIalpha from the residual nuclear matrix. Using a high dilution of the first antibody, we established that the high level of heterochromatin compactisation in the interphase nuclei is caused by the high concentration of DNA topoisomerase IIalpha.

Spatial and structural segregation of the transcribed and nontranscribed alleles of c-myc in Namalva-S cells.

By using various approaches we received evidence that, in Namalva-S cells carrying a t(8;14) translocation and highly expressing c-myc, the two alleles of the gene are spatially and structurally segregated. Spatial segregation of the alleles was observed in all nuclei analyzed by in situ hybridization technique. Their structural segregation, i.e., association with different intranuclear structures, was confirmed in a number of experiments. When high-salt extracted nuclei were digested with EcoRI, which is known to produce fragments containing the entire c-myc locus, the sequences of the gene were found separated between the pellet, containing sequences firmly associated with the heavier matrix structures, and the supernatant, containing sequences from the free length of the DNA loops. Southern hybridization performed with a probe representative for the constant region of the human IgH locus revealed that this fractionation in fact segregates the reorganized from the normal allele of c-myc. Run-on experiments carried out with two fractions, topologically equivalent to the above P and S but isolated as intact chromatin structures, indicated that the allele associated with nuclear matrix is actively transcribed, while that located in the free length of the chromatin loops is practically nontranscribed. Studies on the chromatin organization of transcribed and nontranscribed alleles revealed the existence in them of two alternative chromatin structures. Control experiments with beta-globin gene, performed with cells constitutively nontranscribing or actively transcribing this gene, confirmed our conclusions about the spatial segregation of the two alleles and clarified that their structural segregation occurs when the gene is activated for transcription.

Gene reorganisations and expression of c-ras, c-src, c-mos and c-fos oncogenes in Namalwa, Wish and C6 cells.

In a wide variety of neoplasms, proto-oncogenes were found transcriptionally activated by different DNA rearrangements. In the present study we used Namalwa, Wish and C6 cell lines in order to investigate the correlation between gene reorganisations and their expression. According to Southern and fluorescence in situ hybridisation (FISH) analysis the oncogenes c-ras, c-src and c-fos were amplified in Namalwa and Wish cells. reorganisation other than amplification was found for c-mos in the three cell cultures investigated. The amplification levels of the genes studied were assessed by dot blot hybridisation followed by densitometric scanning. c-H-ras and c-src were amplified about 20-fold in the genomes of Namalwa and Wish, while c-fos was amplified approximately 12-fold in the same cell lines. The hybridisation signals in C6 were almost the same as in the control lymphocytes for the four oncogenes investigated. Similar results were obtained for c-mos in the genomes of all cell lines examined. Using RT-PCR, overexpression of proto-oncogenes c-ras, c-src, c-mos and c-fos was found in Namalwa and Wish cells. In C6 cells the expression of the four genes studied was marginal. Overexpression of c-mos was observed in Namalwa and Wish cells, while in C6 it was marginal although existence of reorganisation was found. Hence, it might be suggested that in C6 cells c-mos is down-regulated from other factors and/or genes, or requires for its activation overexpression of other genes.

Adult attention deficit hyperactivity disorder: translating research into practice.

Attention deficit hyperactivity disorder (ADHD) in adults is a prevalent, yet under-appreciated, under-researched and poorly understood condition. Given this, it is imperative that information and awareness regarding this condition are made more widespread, both amongst the general public and amongst healthcare professionals. Further, given our poor understanding of the aetiology of the condition, meaningful translational research that migrates into and better informs clinical practice must be a priority. In this brief review we highlight areas regarding the clinical diagnosis and management of ADHD in adults (guidelines, rating scales, pharmacotherapy, psychotherapy) as well as areas of promising translational research (genetics, neuroimaging, sleep and circadian rhythms, animal models of ADHD). We address some of the challenges presented for both clinicians and healthcare providers and research scientists working to improve the lives of those adults with ADHD.

Pilot study of the application of magnetic bead protein profiling to the study of biomarkers in addiction research.

OBJECTIVES: Proteomic technologies based on mass spectrometry are increasingly used as a valuable tool in clinical research allowing high-throughput protein and peptide profiling to be undertaken. Whilst previous research has focussed the application of this novel technology on the study of patients with disorders compared to comparable individuals from the healthy population, this current study seeks to determine the effect of successful treatment for alcoholism on the serum protein profile obtained. METHODS: Serum samples were collected from patients after initial treatment for alcohol abuse and also 6 months after treatment. The serum samples were prepared for analysis using reverse phase magnetic bead fractionation and the resulting peptides analysed by matrix assisted laser desorption ionisation time-of-flight (MALDI-ToF) mass spectrometry. RESULTS: Whilst the majority of the peptides detected by this approach exhibited constant levels between the two time points, three peptides were elevated at the 6-month time point compared to the initial sampling. CONCLUSIONS: Whilst disorders with very clear biological causes (such as cancer) exhibit significantly different peptide profiles, psychiatric disorders such as alcohol addiction which are multifactorial show less obvious changes. Despite this the two groups of samples could statistically be distinguished by certain peptides expression levels.

The type of DNA attachment sites recovered from nuclear matrix depends on isolation procedure used.

A large variety of DNA sequences have been described in nuclear matrix attachment regions. It could be most likely a result of the different methods used for their isolation. The idea about how different types of known DNA sequences (strongly attached to the nuclear matrix, weakly attached, or not attached) directly participate in anchoring DNA loops to the nuclear matrices isolated by different experimental procedures was tested in this study. Matrix-attached (M) and matrix-independent or loop (L) fractions as well as nuclear matrices were isolated using extractions of nuclei with 25 mM lithium 3,5-diiodosalicylate (LIS), 2 M NaCl, 0.65 M ammonium sulphate containing buffers followed by DNase I/RNase A digestion, or according to so designated conventional method. Using PCR-based and in vitro binding assays it was established that LIS and ammonium sulphate extractions gave similar results for the type of attachment of sequences investigated. The harsh extraction with 2 M NaCl or the conventional procedure led to some rearrangements in the attachment of DNA loops. As a result a big part of matrix attached sequences were found detached in the loop fractions. However, the in vitro binding abilities of the MARs to the nuclear matrices isolated by different methods did not change.