Michelle Downes

2D-DIGE as a Strategy To Identify Serum Markers for the Progression of Prostate Cancer

Prostate cancer is the most common solid organ malignancy affecting men in the United States and Western Europe. Currently, the main diagnostic tools used to look for evidence of prostate cancer include physical examination using digital rectal exam (DRE), serum concentrations of prostate specific antigen (PSA) and biopsy. However, due to the low specificity of PSA in differentiating prostate cancer from other benign conditions, many patients undergo overtreatment for their disease. There is an urgent need for additional markers to improve the diagnostic accuracy for early stages of prostate cancer. Proteomic analysis of serum has the potential to identify such markers. An initial discovery study has been completed using 12 serum samples from patients with different grades of prostate cancer (Gleason score 5 and 7) undergoing radical prostatectomy. Serum samples were subjected to immunoaffinity depletion and protein expression analysis using 2D-DIGE. Image analysis isolated 63 spots that displayed differential expression between the Gleason score 5 and 7 cohorts (p < 0.05), 13 of which were identified as statistically significant using two independent image analysis packages. Identification of differentially expressed spots was carried out using LC-MS/MS. Because of their functional relevance and potential significance with regards to prostate cancer progression, two of these proteins, pigment epithelium-derived factor (PEDF) and zinc-alpha2-glycoprotein (ZAG), have undergone extensive validation in serum and tissue samples from the original cohort and also from a larger independent cohort of patients. These results have indicated that PEDF is a more accurate predictor of early stage prostate cancer. We are confident that proteomics-based approaches have the potential to provide more insight into the underlying molecular mechanisms of the disease and also hold great promise for biomarker discovery in prostate cancer.

Urinary markers for prostate cancer

Prostate cancer is the commonest solid‐organ malignancy to affect men in Europe and the USA; it is estimated that one in six men will develop this cancer in their lifetime. Current screening relies on a digital rectal examination with a serum prostate‐specific antigen test. Novel urinary diagnostic tests are potentially interesting screening tools for this disease. We examined published reports assessing the use of urinary markers for the diagnosis of prostate cancer. Using a PubMed‐based search we identified studies of urinary markers for prostate cancer published from 1985 to February 2006 using the search terms ‘urine’, ‘marker’ and ‘prostate cancer’. Studies to date have used small cohorts and relied on prostatic biopsies to provide histology. The sensitivity and specificity of markers are wide ranging but with only a few studies published on each putative marker it is difficult to assess their potential impact. Using urinary biomarkers for prostate cancer is a relatively novel diagnostic approach; they are appealing as a screening test because they are not invasive. Further work is needed to identify and validate ‘signature markers’ indicative of prostatic malignancy. The newer proteomic platforms are promising biomarker discovery tools that might uncover the next generation of urinary biomarkers.

Application of proteomic strategies to the identification of urinary biomarkers for prostate cancer: A review

Abstract In the post-genomic era, genes and proteins are now studied on a more comprehensive scale. Studying disease processes at only the genetic or transcriptomic level will give an incomplete amount of information. A proteomic approach potentially allows for a more global overview of how disease processes affect the proteins present in cells, tissues and organisms. The challenge arises in determining which proteins are affected in specific diseases and establishing which of these changes are unique to a particular disease. Existing and emerging proteomic technologies allow for high throughput analysis of proteins in a variety of sample types. Prostate cancer is a significant male health problem in the Western world. It is widely accepted that more specific prognostic and diagnostic markers of prostate cancer are urgently required. The present paper suggests that urine may be an attractive biofluid in which to pursue the identification of novel biomarkers of prostate cancer. This review introduces some proteomic techniques including mass spectrometry and the newer, quantitative proteomic strategies. It focuses on the potential application of these platforms to novel urinary biomarker identification in prostate malignancy. It also includes a synopsis of the current literature on urinary proteomics.

Event-related potential measures of executive functioning from preschool to adolescence

Executive functions are a collection of cognitive abilities necessary for behavioural control and regulation, and are important for school success. Executive deficits are common across acquired and developmental disorders in childhood and beyond. This review aims to summarize how studies using event‐related potential (ERP) can provide insight into mechanisms underpinning how executive functions develop in children from preschool to adolescence. We specifically focus on ERP components that are considered to be well‐established markers of executive functioning, including the ability to resist distraction (inhibition, N200), hold scenes in mind (visuospatial working memory, contralateral delay activity), attend to specific stimuli (information processing, P300), follow rules (response monitoring, error‐related negativity [ERN], and error‐related positivity [Pe]), and adjust to feedback (outcome monitoring, feedback‐related negativity). All of these components show developmental changes from preschool to adolescence, in line with behavioural and neuroimaging findings. These ERP markers also show altered developmental trajectories in the context of atypical executive functions. As an example, deficits in executive function are prominently implicated in attention‐deficit–hyperactivity disorder. Therefore, this review highlights ERP studies that have investigated the above ERP components in this population. Overall, ERPs provide a useful marker for the development and dysfunction of executive skills, and provide insight into their neurophysiological basis.

Outcome following multiple subpial transection in Landau‐Kleffner syndrome and related regression

To determine whether multiple subpial transection in the posterior temporal lobe has an impact on long‐term outcome in children who have drug‐resistant Landau‐Kleffner syndrome (LKS) or other “electrical status epilepticus during sleep” (ESES)‐related regression. Given the wide variability in outcomes reported in the literature, a secondary aim was to explore predictors of outcome.

Fasting status as a consideration for human serum collection and preparation prior to depletion and analysis

The use of comparative serum proteomic analysis has the potential to reveal protein expression changes present at different stages of disease progression. Depletion strategies allow for the enrichment of low‐abundance proteins, which are more likely to be clinically significant biomarkers. We have observed that patient serum samples filtered through 0.22 μm cellulose acetate spin filters prior to depletion showed a variable level of retention of patient material on the upper part of the filter. This could potentially be related to the fasting status of the patient as a reduction in the lipid content of samples through the incorporation of a centrifugation step prior to filtration was found to reduce this effect. In order to determine if proteins were being selectively retained during filtration, a 2‐D difference gel electrophoresis (2‐D DIGE) experiment was performed. This demonstrated no significant selective retention of protein within crude serum samples. However, as this analysis was carried out on crude serum, it must be emphasised that protein loss could be manifest in the low‐abundance proteins which would be masked in our analysis. Depletion of the retentate was not possible due to technical limitations, however based on our results a centrifugation step might act as an alternative to filtration in serum processing prior to depletion.

Prevalence and risk factors for autism spectrum disorder in epilepsy: a systematic review and meta-analysis

To assess the prevalence and risk factors for autism spectrum disorder (ASD) in epilepsy, and to better understand the relationship and comorbidity between these disorders.

Altered Neurophysiological Processing of Auditory Attention in Preschool Children With Sickle Cell Disease

Objective Sickle cell disease (SCD) is a genetic red blood cell disorder that often leads to stroke and executive dysfunction in school-age children and adults. This study aimed to characterize the development of the neural correlates of selective attention, an early component of executive function, in preschool children with SCD. Methods Auditory event-related potentials (ERPs) were recorded while children attended to a story stream in one ear and ignored a second story in the other ear interchangeably. In total, 12 patients (mean age = 5.5, 7 males) and 22 typically developing children (mean age = 4.4, 10 males) were included in the final analyses. Results By 100 ms, more positive ERP amplitudes were observed for attended relative to unattended stimuli in typically developing children but not those with SCD, suggesting deficits in the ability to focus attention. Reduced attention effects were associated with lower performance intellectual quotient. Conclusion There are deficits in early attention modulation in young children with SCD.

Parent reported sleep problems in preschool children with sickle cell anemia and controls in East London

Snoring and poor sleep may affect cognition, particularly in young children with chronic conditions. Parents of London preschoolers with sickle cell anemia (SCA; n = 22), matched controls (n = 24), and unselected typically developing (n = 142) preschoolers completed sleep questionnaires. Preschoolers with SCA had significantly more sleep problems when compared to matched controls and the larger population. Snoring occurred at least one to two nights a week for 79% of the SCA group. This is compared with 25% of matched controls and 33% of larger population. Randomized controlled trials to improve sleep in young children with SCA already at‐risk for cognitive dysfunction should be considered.

Visual attention control differences in 12-month-old preterm infants

There have been few previous attempts to assess the development of early markers of executive function in infants born preterm despite well-established deficits reported for older preterm children that have been closely linked to poorer academic functioning. The present study investigates early attention control development in healthy 12-month-old age-corrected pre-term infants who were born less than 30 weeks and compares their performance to full-term infants. Eye-tracking methodology was used to measure attention control. Preterm Infants spent less time focused on the target and were slower to fixate attention, with lower gestational age associated with poorer target fixation and slower processing speed. There were no significant group differences observed for inhibition of return or interference control. These findings suggest that specific emerging deficits in attention control may be observed using eye tracking methodology in very preterm infants at this early stage of development, despite scores within the average range on the Bayley Scales of Infant Development.