Differential impact of the FMR-1 full mutation on memory and attention functioning : a neuropsychological perspective.

Memory and attention processing were examined in a group of 15 adult Fragile-X syndrome (FXS) males with Fragile-X mental retardation 1 (FMR-1) full mutation and compared to two control groups: a learning disabled (LD) control and a normal functioning control. Performance was assessed across a wide range of tasks including working memory, recognition memory, selective attention, sustained attention, and attentional switching. All three groups performed at a comparable level on recognition memory tasks, and the Fragile-X males and LD control group performed worse than the control group on tasks of working memory and sustained attention.

Refractometric discrimination of void-space filling and swelling during vapour sorption in polymer films.

Thin polymeric films have been deposited as upper cladding layers on a new integrated optical interferometer fabricated from layers of silicon oxynitride on a silicon wafer. The evanescent field of the probing waveguide mode transduces refractive index changes in the polymer layer into the measured phase changes in the device. Real-time measurement of index change and its sign is obtained.

Loss of heterozygosity in bilateral breast cancer.

Women who develop bilateral breast cancer at an early age are likely to harbour germline mutations in breast cancer susceptibility genes. The aim of this study was to test for concordant genetic changes in left and right breast cancer of young women (age < 50) with bilateral breast cancer that may suggest an inherited breast cancer predisposition. Microsatellite markers were used to test for loss of heterozygosity (LOH) in left and right tumours for 31 women with premenopausal bilateral breast cancer.

Genetic manipulation indicates that ARD1 is an essential N(alpha)-acetyltransferase in Trypanosoma brucei.

N(alpha)-acetylation, the most common protein modification, involves the transfer of an acetyl group from acetyl-coenzyme A to the N-terminus of a protein or peptide. The major N(alpha)-acetyltransferase in Saccharomyces cerevisiae is the ARDI-NATI complex. To investigate N(alpha) -acetylation in Trypanosoma brucei we have cloned and characterised genes encoding putative homologues of ARD1 and NAT1.

The molecular karyotype of the megabase chromosomes of Trypanosoma brucei stock 427.

We present the molecular karyotype of the megabase chromosomes of Trypanosoma brucei stock 427, clone 221a. This cloned stock is most commonly used in research laboratories in genetic manipulation experiments and in studies of antigenic variation. Using 116 previously characterised chromosome-specific markers, we identify 11 diploid pairs of megabase chromosomes and detect no loss of synteny in EST and gene marker distribution between this stock and the genome project reference stock TREU 927/4.

t-loops at trypanosome telomeres.

Mammalian telomeres form large duplex loops (t-loops) that may sequester chromosome ends by invasion of the 3' TTAGGG overhang into the duplex TTAGGG repeat array. Here we document t-loops in Trypanosoma brucei, a kinetoplastid protozoan with abundant telomeres due to the presence of many minichromosomes. These telomeres contained 10-20 kb duplex TTAGGG repeats and a 3' TTAGGG overhang.

Expression-site-associated gene 8 (ESAG8) of Trypanosoma brucei is apparently essential and accumulates in the nucleolus.

Trypanosoma brucei variant surface glycoprotein expression sites are interesting examples of genomic loci under complex epigenetic control. In the infectious bloodstream stage, only one of about 20 expression sites is actively transcribed. In the Tsetse midgut (procyclic) stage, chromatin remodeling silences all expression sites.

Trypanosoma cruzi: cloning and characterization of a RAB7 gene.

The small monomeric GTP-binding proteins of the RAB subfamily are key regulatory elements of the machinery that controls membrane traffic in eukaryotic cells. These proteins have been localized to many different intracellular organelles, on both endocytic and exocytic compartments, suggesting that each step of vesicular traffic can involve a specific RAB protein. The presence of conserved amino acid domains in these proteins has allowed the cloning of their genes from several organisms, including yeast, plants, humans, and parasites.

Measurement of locus copy number by hybridisation with amplifiable probes.

Despite its fundamental importance in genome analysis, it is only recently that systematic approaches have been developed to assess copy number at specific genetic loci, or to examine genomic DNA for submicro-scopic deletions of unknown location. In this report we show that short probes can be recovered and amplified quantitatively following hybridisation to genomic DNA. This simple observation forms the basis of a new approach to determining locus copy number in complex genomes.

Conditional expression of glycosylphosphatidylinositol phospholipase C in Trypanosoma brucei.

Trypanosoma brucei glycosylphosphatidylinositol phospholipase C (GPIPLC) is expressed in the bloodstream stage of the life cycle, but not in the procyclic form. It is capable of hydrolyzing GPI-anchored proteins and phosphatidylinositol (PI) in vitro. Several roles have been proposed for GPIPLC in vivo, in the release of variant surface glycoprotein during differentiation or in the regulation of GPI and PI levels, but none has been substantiated.

Methods of detection of Chlamydia psittaci in domesticated and wild birds.

Objective: To study the occurrence of Chlamydia psittaci in domesticated and wild birds and compare the sensitivity of molecular detection with cell culture isolation.

Design: Study of cell culture isolation and PCR detection of C psittaci in avian samples.

Procedure: Samples were obtained from 485 birds.

A neuropsychological-genetic profile of atypical cri du chat syndrome: implications for prognosis.

Cri du chat syndrome is associated with a deletion on the short arm of chromosome 5. The main diagnostic feature is a high pitched, cat-like cry which has recently been localised to 5p15.3 and is separate from the remaining clinical features of the syndrome, which have been localised to 5p15.

Spatial cognition in males with Fragile-X syndrome: evidence for a neuropsychological phenotype.

Spatial performance in a group of young Fragile-X syndrome males with FMR-1 full mutation was compared to a learning disabled control group comprising young Down's syndrome males and two control groups of mainstream schoolchildren. Performance was assessed across a wide range of spatial tasks including visuo-construction, visuo-spatial memory, visuo-motor, and visuo-perception. The findings indicate a task-specific rather than global deficit in spatial performance in Fragile-X males with visuo-constructive and visuo-motor skills most vulnerable.

Detection of herpes simplex virus in genital specimens by type-specific polymerase chain reaction.

Viral isolation is the standard method for the detection of herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) in clinical specimens. This study describes the development of a type-specific polymerase chain reaction (PCR) assay for detection and typing of HSV-1 and HSV-2, and a comparison of its sensitivity with that of isolation in a clinical setting. Specimens from patients presenting with genital ulcers were tested for the presence of HSV by both methods.

A tightly regulated inducible expression system for conditional gene knock-outs and dominant-negative genetics in Trypanosoma brucei.

First-generation inducible expression vectors for Trypanosoma brucei utilized a single tetracycline-responsive promoter to drive expression of an experimental gene, in tandem with a drug-resistance marker gene to select for integration (Wirtz E, Clayton CE. Science 1995; 268:1179-1183). Because drug resistance and experimental gene expression both depended upon the activity of the regulated promoter, this approach could not be used for inducible expression of toxic products.

Trypanosoma brucei variant surface glycoprotein regulation involves coupled activation/inactivation and chromatin remodeling of expression sites.

Trypanosoma brucei is an extracellular protozoan parasite that cycles between mammalian hosts and the tsetse vector. In bloodstream-form trypanosomes, only one variant surface glycoprotein gene (VSG) expression site (ES) is active at any time. Transcriptional switching between ESs results in antigenic variation.

[Diagnostic imaging in Cushing's disease and its correlation with postsurgical clinical course].

Unlabelled: The purpose of this paper was to assess the accuracy of computed tomography (CT) and magnetic resonance (MR) in the preoperative identification of corticotropin-secreting pituitary adenomas and to evaluate the concordance with the postoperative outcome. A total of 44 images of patients with Cushing's disease were retrospectively taken into consideration; 23 CT and 29 MR were evaluated. Patients were subdivided into remission or persistence, following the postoperative outcome and biochemical tests.

The nature of the spatial deficit in young females with Fragile-X syndrome: a neuropsychological and molecular perspective.

Spatial performance in a group of young Fragile-X syndrome females with FMR-1 full mutation was compared to two control groups of mainstream schoolchildren. Performance was assessed across a wide range of spatial tasks including visuo-spatial, visuo-construction, visuo-motor, visuo-perception and spatial-memory. A spatial deficit emerged only on those tasks which comprised a visuo-constructive component, with the Fragile-X group performing worse overall.

Regulated processive transcription of chromatin by T7 RNA polymerase in Trypanosoma brucei.

Inability of T7 RNA polymerase to processively transcribe higher eukaryotic chromatin is interpreted as a correlate of its reported inhibition by nucleosomes on reconstituted templates in vitro . We used chromosomally integrated reporter cassettes to examine features of T7 transcription in a lower eukaryotic system. Luciferase reporters were targeted to rDNA in transgenic Trypanosoma brucei stably expressing the phage polymerase.

In situ analysis of a variant surface glycoprotein expression-site promoter region in Trypanosoma brucei.

In Trypanosoma brucei, the active variant surface glycoprotein genes (vsg) are located at telomeric expression sites (ES), whose expression is highly regulated during the life cycle. In the procyclic form, all ESs are repressed. In the bloodstream form, where antigenic variation occurs, only one of approximately 20 ESs is active at a given time.

Regulation of vsg expression site transcription and switching in Trypanosoma brucei.

Current understanding of expression-site transcription in Trypanosoma brucei, has been refined by recent results of promoter manipulations at vsg expression sites (ES) and examination of the behavior of ES promoters in ectopic locations both within the ES and at other loci. In summary, ES promoter sequences inserted into non-transcribed rRNA spacers are generally inactive, or have low activity, in bloodstream and procyclic forms. Some mechanism apparently operates to ensure full activation of a single ES in bloodstream-form trypanosomes and the inactivity of all ES promoters in procyclic forms.

Position-dependent and promoter-specific regulation of gene expression in Trypanosoma brucei.

Trypanosoma brucei evades the mammalian immune response by a process of antigenic variation. This involves mutually exclusive and alternating expression of telomere-proximal variant surface glycoprotein genes (vsgs), which is controlled at the level of transcription. To examine transcription repression in T.