An endogenous glycosylphosphatidylinositol-specific phospholipase D releases basic fibroblast growth factor-heparan sulfate proteoglycan complexes from human bone marrow cultures

Basic fibroblast growth factor (bFGF) is a hematopoietic cytokine that stimulates stromal and stem cell growth. It binds to a glycosylphosphatidylinositol (GPI)-anchored heparan sulfate proteoglycan on human bone marrow (BM) stromal cells. The bFGF- proteoglycan complex is biologically active and is released by addition of exogenous phosphatidylinositol-specific phospholipase C. In this study, we show the presence of an endogenous GPI-specific phospholipase D (GPI-PLD) that releases the bFGF-binding heparan sulfate proteoglycan and the variant surface glycoprotein (a model GPI-anchored protein) from BM cultures. An involvement of proteases in this process is unlikely, because released proteoglycan contained the GPI anchor component, ethanol-amine, and protease inhibitors did not diminish the release. The mechanism of release is likely to involve a GPI-PLD and not a GPI-specific phospholipase C, because the release of variant surface glycoprotein did not reveal an epitope called the cross- reacting determinant that is exposed by phospholipase C-catalyzed GPI anchor cleavage. In addition, phosphatidic acid (which is specifically a product of GPI-PLD-catalyzed anchor cleavage) was generated during the spontaneous release of the GPI-anchored variant surface glycoprotein. We also detected GPI-PLD-specific enzyme activity and mRNA in BM cells. Therefore, we conclude that an endogenous GPI-PLD releases bFGF-heparan sulfate proteoglycan complexes from human BM cultures. This mechanism of GPI anchor cleavage could be relevant for mobilizing biologically active bFGF in BM. An endogenous GPI-PLD could also release other GPI-anchored proteins important for hematopoiesis and other physiologic processes.     

Study of nuclear diameters in non-Hodgkin's lymphomas

The mean maximum nuclear diameter (D_max) in 21 cases of non-Hodgkin's lymphoma (NHL) has been determined, using the Reichert-Jung (Kontron) MOP-AMO₃ user-controlled image analyser. Nuclear diameters of high-grade malignancy NHL were found to be considerably greater than those of low-grade malignancy lymphomas, although there was some overlap of their ranges. These findings confirm objectively subjective estimates of nuclear size in NHL. The relative usefulness of the user-controlled (interactive) image analyser for the measurement of nuclei in tissue sections is compared with that of a fully automatic machine.     

Workplace Social Challenges Experienced by Employees on the Autism Spectrum: An International Exploratory Study Examining Employee and Supervisor Perspectives

Social challenges represent a significantly under-researched area when it comes to the poor employment outcomes in autism. In this exploratory study employees on the autism spectrum (N?=?29) and supervisors (N?=?15), representing seven continents, provided 128 written examples of workplace-based social challenges, their interpretation, consequences and resolution. Content analysis revealed that types of social challenges were individually oriented or associated with the work-environment. Social challenges were frequently attributed to internal or personal factors with direct consequences for the employee. Resolutions were more frequently targeted toward the individual than the workplace, and hindered employees’ experience of work. This international study represents a first look at the types of social challenges that impact equitable work participation of autistic people.

     

Effect of retinal and/or extra-retinal information on age in memory-guided saccades

The aim of the study was to determine whether the addition of retinal or extra-retinal information could be used to improve memory-guided saccadic performance in healthy participants. Furthermore, we included two age groups in our study; healthy young adult subjects (mean age 20 years) and healthy middle-aged adult subjects (mean age 52 years). All subjects performed a novel task that incorporated a Go/NoGo task with a memory-guided saccade paradigm to investigate whether extra-retinal information (making a saccade towards the visible target) or retinal (a visible frame-of-reference) has any affect on the accuracy or variability of the response. We found all subjects made slight hypometric responses to the memory-guided targets. Both younger and middle-aged subjects revealed an increase in accuracy in the Go task compared with the NoGo task and the framed condition compared to the frameless condition, respectively. The frame also revealed a significant decrease in variability in the memory-guided saccades. A positive correlation in errors between the 1st and 2nd saccade in the Go task was revealed for all subjects; however, the older subjects revealed a greater correlation than younger subjects. The results presented indicate that younger and middle-aged perform highly similar patterns of errors during eye movements to remembered locations. However, middle-aged subjects show a greater tendency to use extra-retinal and retinal feedback to guide the response.     

An evaluation of the challenges to developing tumor BRCA1 and BRCA2 testing methodologies for clinical practice

Ovarian cancer patients with germline or somatic pathogenic variants benefit from treatment with poly ADP ribose polymerase (PARP) inhibitors. Tumor BRCA1/2 testing is more challenging than germline testing as the majority of samples are formalin‐fixed paraffin embedded (FFPE), the tumor genome is complex, and the allelic fraction of somatic variants can be low. We collaborated with 10 laboratories testing BRCA1/2 in tumors to compare different approaches to identify clinically important variants within FFPE tumor DNA samples. This was not a proficiency study but an inter‐laboratory comparison to identify common issues. Each laboratory received the same tumor DNA samples ranging in genotype, quantity, quality, and variant allele frequency (VAF). Each laboratory performed their preferred next‐generation sequencing method to report on the variants. No false positive results were reported in this small study and the majority of methods detected the low VAF variants. A number of variants were not detected due to the bioinformatics analysis, variant classification, or insufficient DNA. The use of hybridization capture or short amplicon methods are recommended based on a bioinformatic assessment of the data. The study highlights the importance of establishing standards and standardization for tBRCA testing particularly when the test results dictate clinical decisions regarding life extending therapies.     

Diagnostic yield,interpretation, and clinical utility of mutation screening of sarcomere encoding genes in Danish hypertrophic cardiomyopathy patients and relatives

The American Heart Association (AHA) recommends family screening for hypertrophic cardiomyopathy (HCM). We assessed the outcome of family screening combining clinical evaluation and screening for sarcomere gene mutations in a cohort of 90 Danish HCM patients and their close relatives, in all 451 persons. Index patients were screened for mutations in all coding regions of 10 sarcomere genes (MYH7, MYL3, MYBPC3, TNNI3, TNNT2, TPM1, ACTC, CSRP3, TCAP, and TNNC1) and five exons of TTN. Relatives were screened for presence of minor or major diagnostic criteria for HCM and tracking of DNA variants was performed. In total, 297 adult relatives (>18 years) (51.2%) fulfilled one or more criteria for HCM. A total of 38 HCM‐causing mutations were detected in 32 index patients. Six patients carried two disease‐associated mutations. Twenty‐two mutations have only been identified in the present cohort. The genetic diagnostic yield was almost twice as high in familial HCM (53%) vs. HCM of sporadic or unclear inheritance (19%). The yield was highest in families with an additional history of HCM‐related clinical events. In relatives, 29.9% of mutation carriers did not fulfil any clinical diagnostic criterion, and in 37.5% of relatives without a mutation, one or more criteria was fulfilled. A total of 60% of family members had no mutation and could be reassured and further follow‐up ceased. Genetic diagnosis may be established in approximately 40% of families with the highest yield in familial HCM with clinical events. Mutation‐screening was superior to clinical investigation in identification of individuals not at increased risk, where follow‐up is redundant, but should be offered in all families with relatives at risk for developing HCM. Hum Mutat 0,1–8, 2008. © 2008 Wiley‐Liss, Inc.