Suppression of Richtmyer-Meshkov Instability via Special Pairs of Shocks and Phase Transitions

The classical Richtmyer-Meshkov instability (RMI) is a hydrodynamic instability characterizing the evolution of an interface following shock loading. In contrast to other hydrodynamic instabilities such as Rayleigh-Taylor, it is known for being unconditionally unstable: regardless of the direction of shock passage, any deviations from a flat interface will be amplified. In this article, we show that for negative Atwood numbers, there exist special sequences of shocks which result in a nearly perfectly suppressed instability growth. We demonstrate this principle computationally and experimentally with stepped fliers and phase transition materials. A fascinating immediate corollary is that in specific instances, a phase-transitioning material may self-suppress RMI.

Pediatric Cardiology Fellowship Standards for Training in Exercise Medicine and Curriculum Outline

Over the past 2 decades, fundamentals of exercise medicine, including clinical exercise testing, assessment and promotion of physical activity, exercise prescription, and supervised exercise training/rehabilitation programming have demonstrated considerable clinical value in the management of children and adolescents with congenital and acquired heart disease. Although the principles of exercise medicine have become an integral component in pediatric cardiology, there are no standardized training recommendations for exercise physiology during pediatric cardiology fellowship at this time. Thus, the Pediatric Cardiology Exercise Medicine Curriculum Committee (PCEMCC) was formed to establish core and advanced exercise physiology training recommendations for pediatric cardiology trainees. The PCEMCC includes a diverse group of pediatric cardiologists, exercise physiologists, and fellowship program directors. The expert consensus training recommendations are by no means a mandate and are summarized herein, including suggestions for achieving the minimum knowledge and training needed for general pediatric cardiology practice.

A Prospective Evaluation of Infant Cerebellar-Cerebral Functional Connectivity in Relation to Behavioral Development in Autism Spectrum Disorder

Background

Autism spectrum disorder (ASD) is a neurodevelopmental disorder diagnosed based on social impairment, restricted interests, and repetitive behaviors. Contemporary theories posit that cerebellar pathology contributes causally to ASD by disrupting error-based learning (EBL) during infancy. The present study represents the first test of this theory in a prospective infant sample, with potential implications for ASD detection.

Methods

Data from the Infant Brain Imaging Study (n = 94, 68 male) were used to examine 6-month cerebellar functional connectivity magnetic resonance imaging in relation to later (12/24-month) ASD-associated behaviors and outcomes. Hypothesis-driven univariate analyses and machine learning-based predictive tests examined cerebellar-frontoparietal network (FPN; subserves error signaling in support of EBL) and cerebellar-default mode network (DMN; broadly implicated in ASD) connections. Cerebellar-FPN functional connectivity was used as a proxy for EBL, and cerebellar-DMN functional connectivity provided a comparative foil. Data-driven functional connectivity magnetic resonance imaging enrichment examined brain-wide behavioral associations, with post hoc tests of cerebellar connections.

Results

Cerebellar-FPN and cerebellar-DMN connections did not demonstrate associations with ASD. Functional connectivity magnetic resonance imaging enrichment identified 6-month correlates of later ASD-associated behaviors in networks of a priori interest (FPN, DMN), as well as in cingulo-opercular (also implicated in error signaling) and medial visual networks. Post hoc tests did not suggest a role for cerebellar connections.

Conclusions

We failed to identify cerebellar functional connectivity-based contributions to ASD. However, we observed prospective correlates of ASD-associated behaviors in networks that support EBL. Future studies may replicate and extend network-level positive results, and tests of the cerebellum may investigate brain-behavior associations at different developmental stages and/or using different neuroimaging modalities.

Inter- and intra-tract analysis of white matter abnormalities in individuals with early-treated phenylketonuria (PKU)

Even with early and continuous treatment, individuals with phenylketonuria (PKU) may exhibit abnormalities of cortical white matter (WM). The present study utilizes a new analysis approach called Automated Fiber-Tract Quantification (AFQ) to advance our understanding of the tract-specific patterns of change in WM abnormalities in individuals with early-treated PKU (ETPKU). Diffusion Tensor Imaging (DTI) data from a sample of 22 individuals with ETPKU and a demographically-matched sample of 21 healthy individuals without PKU was analyzed using AFQ. In addition, a subsample of 8 individuals with ETPKU was reevaluated six months later after demonstrating a significant reduction in blood phe levels following initiation of sapropterin treatment. Within-tract AFQ analyses revealed significant location-by-group interactions for several WM tracts throughout the brain. In most cases, ETPKU-related disruptions in mean diffusivity (MD) were more apparent in posterior (as compared to anterior) aspects of a given tract. Reduction in blood phe levels with the aforementioned ETPKU subsample was associated with a similar pattern of improvement (posterior-to-anterior) within most tracts. Taken together, these findings suggest that there is a systematic pattern of change in WM abnormalities in individuals with ETPKU in a posterior-to-anterior manner along individual WM tracts.

The effects of early-treated phenylketonuria on volumetric measures of the cerebellum

Past murine studies of phenylketonuria (PKU) have documented significant effects on cerebellum at both the gross and cellular levels. The profile of neurocognitive and motor difficulties associated with early-treated PKU (ETPKU) is also consistent with potential cerebellar involvement. Previous neuroanatomical studies of cerebellum in patients with PKU, however, have yielded mixed results. The objective of the present study was to further examine potential differences in cerebellar morphometry between individuals with and without ETPKU. To this end, we analyzed high resolution T1-weighted MR images from a sample of 20 individuals with ETPKU and an age-matched comparison group of 20 healthy individuals without PKU. Measurements of whole brain volume, whole cerebellum volume, cerebellar gray matter volume, and cerebellar white matter volume were collected by means of semiautomatic volumetric analysis. Data analysis revealed no significant group differences in whole brain volume, whole cerebellar volume, or cerebellar white matter volume. A significant reduction in cerebellar gray matter volume, however, was observed for the ETPKU group compared to the non-PKU comparison group. These findings expand on previous animal work suggesting that cerebellar gray matter is impacted by PKU. It is also consistent with the hypothesis that the cognitive difficulties experienced by individuals with ETPKU may be related to disruptions in gray matter. Additional studies are needed to fully elucidate the timing and extent of the impact of ETPKU on cerebellum and the associated neurocognitive consequences.

Exploring the effectiveness of an 18-month weight management intervention in adults with Down syndrome using propensity score matching

BACKGROUND

Down syndrome (DS) is one of the most common birth defects in the USA associated with high levels of overweight and obesity. Unique characteristics of adults with DS that may contribute to the high levels of obesity are high rates of hypothyroidism, poor muscle tone, altered gait and lower resting metabolic rate. Due to these factors, it is unknown if the same weight management interventions that are effective in adults with intellectual or developmental disability (IDD) without DS are as effective in those with DS. Therefore, the purpose of this secondary analysis was to compare changes in weight, diet and physical activity between participants with DS-related and non-DS-related IDD participating in an 18-month weight management trial.

METHODS

We used propensity score methods to adjust baseline variables of overweight/obese adults with and without DS participating in an 18-month effectiveness trial with 6 months weight loss and 12 months weight maintenance. Participants followed one of two reduced calorie diet plans, obtained 150 min of moderate-vigorous intensity physical activity (MVPA) per week, and logged dietary intake daily. A health educator held monthly at-home visits with participants and a caregiver to give feedback on intervention compliance.

RESULTS

Out of the 124 participants that met the criteria for inclusion, 21 were diagnosed with DS and 103 with non-DS-related IDD. Twenty out of 21 participants with DS were successfully matched. Clinically significant weight loss was seen at 18 months in participants with DS (-5.2%) and non-DS-related IDD (-6.8%), with no difference between groups (P = 0.53). Significant reductions in energy intake were seen across the 18-month intervention in both DS and non-DS-related IDD groups with between-group differences at 12 months only (1119 vs. 1492 kcal/day, respectively; P = 0.003). Although MVPA did not increase in either group across the intervention, those with non-DS-related IDD had higher levels of MVPA compared with those with DS across 18 months.

CONCLUSION

Participants with DS lost a clinically significant amount of weight across the 18-month intervention. Compared with those with non-DS-related IDD, those with DS lost similar amounts of weight, had similar decreases in energy intake and participated in less MVPA across the 18-month intervention. Although individuals with DS have physiological factors that may contribute to obesity, weight management interventions designed for individuals with IDD may be equally effective in this population.

White and gray matter brain development in children and young adults with phenylketonuria

Phenylketonuria (PKU) is a recessive disorder characterized by disruption in the metabolism of the amino acid phenylalanine (Phe). Prior research indicates that individuals with PKU have substantial white matter (WM) compromise. Much less is known about gray matter (GM) in PKU, but a small body of research suggests volumetric differences compared to controls. To date, developmental trajectories of GM structure in individuals with PKU have not been examined, nor have trajectories of WM and GM been examined within a single study. To address this gap in the literature, we compared longitudinal brain development over a three-year period in individuals with PKU (n = 35; 18 male) and typically-developing controls (n = 71; 35 male) aged 7–21 years. Using diffusion tensor imaging (DTI) and structural magnetic resonance imaging (MRI), we observed whole-brain and regional WM differences between individuals with PKU and controls, which were often exacerbated with increasing age. In marked contrast with trajectories of WM development, trajectories of GM development did not differ between individuals with PKU and controls, indicating that neuropathology in PKU is more prominent in WM than GM. Within individuals with PKU, mediation analyses revealed that whole-brain mean diffusivity (MD) and regional MD in the corpus callosum and centrum semiovale mediated the relationship between dietary treatment compliance (i.e., Phe control) and executive abilities, suggesting a plausible neurobiological mechanism by which Phe control may influence cognitive outcomes. Our findings clarify the specificity, timing, and cognitive consequences of whole-brain and regional WM pathology, with implications for treatment and research in PKU.

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Individuals with PKU exhibited widespread, age-related white matter compromise.

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Developmental trajectories of gray matter were comparable for PKU and controls.

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Within PKU, white matter compromise influenced cognitive outcomes.

Developmental Trajectories of Executive and Verbal Processes in Children with Phenylketonuria

Phenylketonuria (PKU) is a hereditary disorder characterized by disrupted phenylalanine metabolism and cognitive impairment. However, the precise nature and developmental trajectory of this cognitive impairment remains unclear. The present study used a verbal fluency task to dissociate executive and verbal processes in children with PKU (n = 23; 7-18 years) and controls (n = 44; 7-19 years). Data were collected at three longitudinal timepoints over a three-year period, and the contributions of age, group, and their interaction to fluency performance were evaluated. Results indicated impairments in executive processes in children with PKU, which were exacerbated by declining metabolic control.

Predicting response to neoadjuvant chemoradiotherapy in locally advanced rectal cancer with serum biomarkers

Introduction The aim of this study was to identify patient factors including serum biomarkers that may predict response to neoadjuvant chemoradiotherapy (CRT) in patients with locally advanced rectal cancer staged on magnetic resonance imaging. Prediction of response may be helpful when selecting patients for a non-operative programme. Methods A retrospective review was carried out of patients undergoing neoadjuvant CRT for rectal cancer, conducted at the Royal Devon and Exeter Hospital. All patients were managed through the multidisciplinary team. Receiver operating characteristic (ROC) curve analysis was undertaken to assess the ability of biomarkers to predict response to neoadjuvant CRT. The biomarkers assessed included neutrophils, lymphocytes, monocytes, haemoglobin, platelets, C-reactive protein and carcinoembryonic antigen. Results Seventy-three patients underwent neoadjuvant CRT between January 2006 and December 2011. Nine (12.3%) of these experienced a clinical complete response and were managed with a 'watch and wait' approach. An additional ten patients (13.7%) had a pathological complete response following surgery. Using ROC curve analysis, the biomarkers with the largest area under the curve (AUC) were pre-CRT haemoglobin and post-CRT lymphocyte concentrations, producing AUC values of 0.673 and 0.618 respectively for clinical complete response. Pre-CRT haemoglobin and neutrophil concentrations produced the highest AUC values for pathological complete response at 0.591 and 0.614 respectively. Conclusions None of the assessed biomarkers offer the ability to predict response to neoadjuvant CRT in patients with rectal cancer. They cannot therefore assist in identifying complete clinical or pathological responders who could be considered for a non-operative, observational approach.

Pretreatment cognitive and neural differences between sapropterin dihydrochloride responders and non-responders with phenylketonuria

Sapropterin dihydrochloride (BH₄) reduces phenylalanine (Phe) levels and improves white matter integrity in a subset of individuals with phenylketonuria (PKU) known as “responders.” Although prior research has identified biochemical and genotypic differences between BH₄ responders and non-responders, cognitive and neural differences remain largely unexplored. To this end, we compared intelligence and white matter integrity prior to treatment with BH₄ in 13 subsequent BH₄ responders with PKU, 16 subsequent BH₄ non-responders with PKU, and 12 healthy controls. Results indicated poorer intelligence and white matter integrity in non-responders compared to responders prior to treatment. In addition, poorer white matter integrity was associated with greater variability in Phe across the lifetime in non-responders but not in responders. These results underscore the importance of considering PKU as a multi-faceted, multi-dimensional disorder and point to the need for additional research to delineate characteristics that predict response to treatment with BH_4.

Acute viral bronchiolitis in South Africa: Diagnostic flow

Bronchiolitis may be diagnosed on the basis of clinical signs and symptoms. In a young child, the diagnosis can be made on the clinical pattern of wheezing and hyperinflation. Clinical symptoms and signs typically start with an upper respiratory prodrome, including rhinorrhoea, low-grade fever, cough and poor feeding, followed 1 - 2 days later by tachypnoea, hyperinflation and wheeze as a consequence of airway inflammation and air trapping.The illness is generally self limiting, but may become more severe and include signs such as grunting, nasal flaring, subcostal chest wall retractions and hypoxaemia. The most reliable clinical feature of bronchiolitis is hyperinflation of the chest, evident by loss of cardiacdullness on percussion, an upper border of the liver pushed down to below the 6th intercostal space, and the presence of a Hoover sign(subcostal recession, which occurs when a flattened diaphragm pulls laterally against the lower chest wall).Measurement of peripheral arterial oxygen saturation is useful to indicate the need for supplemental oxygen. A saturation of <92% at sea level and 90% inland indicates that the child has to be admitted to hospital for supplemental oxygen. Chest radiographs are generally unhelpful and not required in children with a clear clinical diagnosis of bronchiolitis.Blood tests are not needed routinely. Complete blood count tests have not been shown to be useful in diagnosing bronchiolitis or guiding its therapy. Routine measurement of C-reactive protein does not aid in management and nasopharyngeal aspirates are not usually done.Viral testing adds little to routine management. Risk factors in patients with severe bronchiolitis that require hospitalisation and may even cause death, include prematurity, congenital heart disease and congenital lung malformations.

Acute viral bronchiolitis in South Africa: Strategies for management and prevention

Management of acute viral bronchiolitis is largely supportive. There is currently no proven effective therapy other than oxygen for hypoxic children. The evidence indicates that there is no routine benefit from inhaled, rapid short-acting bronchodilators, adrenaline or ipratropium bromide for children with acute viral bronchiolitis. Likewise, there is no demonstrated benefit from routine use of inhaled or oral corticosteroids, inhaled hypertonic saline nebulisation, montelukast or antibiotics. The last should be reserved for children with severe disease, when bacterial co-infection is suspected. Prevention of respiratory syncytial virus (RSV) disease remains a challenge. A specific RSV monoclonal antibody, palivizumab, administered as an intramuscular injection, is available for children at risk of severe bronchiolitis, including premature infants, young children with chronic lung disease, immunodeficiency, or haemodynamically significant congenital heart disease. Prophylaxis should be commenced at the start of the RSV season and given monthly during the season. The development of an RSV vaccine may offer a more effective alternative to prevent disease, for which the results of clinical trials are awaited. Education of parents or caregivers and healthcare workers about diagnostic and management strategies should include the following: bronchiolitis is caused by a virus; it is seasonal; it may start as an upper respiratory tract infection with low-grade fever; symptoms are cough and wheeze, often with fast breathing; antibiotics are generally not needed; and the condition is usually self limiting, although symptoms may occur for up to four weeks in some children.

Considerations in the Evaluation of Potential Efficacy of Medications for Alcohol and Drug Use Disorders: An Editorial

The societal burden created by alcohol and drug use disorders is estimated to be on the order of hundreds of billions of dollars, creating a need for effective medications to reduce use and prevent relapse. While there are FDA-approved medications to facilitate abstinence and prevent relapse for some indications including, alcohol, tobacco, and opiate use disorders, there are no approved treatments for other abused substances, including cocaine, methamphetamine, and cannabis, leaving these critical medical needs unmet. The development of such medications has fallen largely to the government with efforts spearheaded by the National Institute on Drug Abuse and the National Institute on Alcoholism and Alcohol Abuse. Both agencies have medication development programs with preclinical components that include the standardized evaluation of compounds using animal models. This chapter describes the rationale and considerations involved in the use of such models, including reinstatement of drug self-administration.

Who gains clinical benefit from using insulin pump therapy? A qualitative study of the perceptions and views of health professionals involved in the Relative Effectiveness of Pumps over MDI and Structured Education (REPOSE) trial

AIMS

To explore health professionals' views about insulin pump therapy [continuous subcutaneous insulin infusion (CSII)] and the types of individuals they thought would gain greatest clinical benefit from using this treatment.

METHODS

In-depth interviews with staff (n = 18) who delivered the Relative Effectiveness of Pumps Over MDI and Structured Education (REPOSE) trial. Data were analysed thematically.

RESULTS

Staff perceived insulin pumps as offering a better self-management tool to some individuals due to the drip feed of insulin, the ability to alter basal rates and other advanced features. However, staff also noted that, because of the diversity of features on offer, CSII is a more technically complex therapy to execute than multiple daily injections. For this reason, staff described how, alongside clinical criteria, they had tended to select individuals for CSII in routine clinical practice based on their perceptions about whether they possessed the personal and psychological attributes needed to make optimal use of pump technology. Staff also described how their assumptions about personal and psychological suitability had been challenged by working on the REPOSE trial and observing individuals make effective use of CSII who they would not have recommended for this type of therapy in routine clinical practice.

CONCLUSIONS

Our findings add to those studies that highlight the difficulties of using patient characteristics and variables to predict clinical success using CSII. To promote equitable access to CSII, attitudinal barriers and prejudicial assumptions amongst staff about who is able to make effective use of CSII may need to be addressed.

Systematic review of guidelines for the assessment and management of high-grade anal intraepithelial neoplasia (AIN II/III)

AIM

There is ambiguity with regard to the optimal management of anal intraepithelial neoplasia (AIN) III. The aim of this review was to assess and compare international/national society guidelines currently available in the literature on the management, treatment and surveillance of AIN III. We also aimed to assess the quality of the studies used to compile the guidelines and to clarify the terminology used in histological assessment.

METHOD

An electronic search of PubMed and Embase was performed using the search terms 'anal intraepithelial neoplasia', 'AIN', 'anal cancer', 'guidelines', 'surveillance' and 'management'. Literature reviews and guidelines or practice guidelines in peer reviewed journals from 1 January 2000 to 31 December 2014 assessing the treatment, surveillance or management of patients with AIN related to human papilloma virus were included. The guidelines identified by the search were assessed for the quality of evidence behind them using the Oxford Centre for Evidence-based Medicine 2011 Levels of Evidence.

RESULTS

The database search identified 5159 articles and two further guidelines were sourced from official body guidelines. After inclusion criteria were applied, 28 full-text papers were reviewed. Twenty-five of these were excluded, leaving three guidelines for inclusion in the systematic review: those published by the Association of Coloproctology of Great Britain and Ireland, the American Society of Colon and Rectal Surgeons and the Italian Society of Colorectal Surgery. No guidelines were identified on the management of AIN III from human papilloma virus associations and societies. All three guidelines agree that a high index of clinical suspicion is essential for diagnosing AIN with a disease-specific history, physical examination, digital rectal examination and anal cytology. There is interchange of terminology from high-grade AIN (HGAIN) (which incorporates AIN II/III) and AIN III in the literature leading to confusion in therapy use. Treatment varies from immunomodulation and photodynamic therapy to targeted destruction of areas of HGAIN/AIN II/III using infrared coagulation, electrocautery, cryotherapy or surgical excision but with little consensus between the guidelines. Recommendations on surveillance strategies are similarly discordant, ranging from 6-monthly physical examination to annual anoscopy ± biopsy. Over 50% of the recommendations are based on Level 3 or Level 4 evidence and many were compiled using studies that were more than 10 years old.

CONCLUSION

Despite concordance regarding diagnosis, there is significant variation in the guidelines over recommendations on the treatment and surveillance of patients with HGAIN/AIN II/III. All three sets of guidelines are based on low level, outdated evidence originating from the 1980s and 1990s.

Altered lipid accumulation in Nannochloropsis salina CCAP849/3 following EMS and UV induced mutagenesis

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EMS and UV mutagenesis of Nannochloropsis salina combined with FACS for mutant enrichment.

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Productivity of EMS mutants increased by 76% and showed range of FA profile changes.

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Dual EMS and UV mutants accumulated 3 fold more lipid than the wild type.

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Elevation in lipid content comes with a cost to growth rate impacting productivity.

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Mutants suitable for divergent industries generated (biofuel, high value PUFA production).

Microalgae have potential as a chemical feed stock in a range of industrial applications. Nannochloropsis salina was subject to EMS mutagenesis and the highest lipid containing cells selected using fluorescence-activated cell sorting. Assessment of growth, lipid content and fatty acid composition identified mutant strains displaying a range of altered traits including changes in the PUFA content and a total FAME increase of up to 156% that of the wild type strain. Combined with a reduction in growth this demonstrated a productivity increase of up to 76%. Following UV mutagenesis, lipid accumulation of the mutant cultures was elevated to more than 3 fold that of the wild type strain, however reduced growth rates resulted in a reduction in overall productivity. Changes observed are indicative of alterations to the regulation of the omega 6 Kennedy pathway. The importance of these variations in physiology for industrial applications such as biofuel production is discussed.

Clinical assessment of organizational strategy: An examination of healthy adults

During the assessment of patients with cognitive difficulties, clinicians often examine strategic processing, particularly the ability to use organization-based strategies to efficiently complete various tasks. Several commonly used neuropsychological tasks are currently thought to provide measures of organizational strategic processing, but empirical evidence for the construct validity of these strategic measures is needed before interpreting them as measuring the same underlying ability. This is particularly important for the assessment of organizational strategic processing because the measures span cognitive domains (e.g., memory strategy, language strategy) as well as types of organization. In the present study, 200 adults were administered cognitive tasks commonly used in clinical practice to assess organizational strategic processing. Factor analysis was used to examine whether these measures of organizational strategic processing, which involved different cognitive domains and types of organization, could be operationalized as measuring a unitary construct. A very good-fitting model of the data demonstrated no significant shared variance among any of the strategic variables from different tasks (root mean square error of approximation < .0001, standardized root-mean-square residual = .045, comparative fit index = 1.000). These findings suggest that organizational strategic processing is highly specific to the demands and goals of individual tasks even when tasks share commonalities such as involving the same cognitive domain. In the design of neuropsychological batteries involving the assessment of organizational strategic processing, it is recommended that various strategic measures across cognitive domains and types of organizational processing are selected as guided by each patient's individual cognitive difficulties.

Phenylketonuria Scientific Review Conference: state of the science and future research needs

New developments in the treatment and management of phenylketonuria (PKU) as well as advances in molecular testing have emerged since the National Institutes of Health 2000 PKU Consensus Statement was released. An NIH State-of-the-Science Conference was convened in 2012 to address new findings, particularly the use of the medication sapropterin to treat some individuals with PKU, and to develop a research agenda. Prior to the 2012 conference, five working groups of experts and public members met over a 1-year period. The working groups addressed the following: long-term outcomes and management across the lifespan; PKU and pregnancy; diet control and management; pharmacologic interventions; and molecular testing, new technologies, and epidemiologic considerations. In a parallel and independent activity, an Evidence-based Practice Center supported by the Agency for Healthcare Research and Quality conducted a systematic review of adjuvant treatments for PKU; its conclusions were presented at the conference. The conference included the findings of the working groups, panel discussions from industry and international perspectives, and presentations on topics such as emerging treatments for PKU, transitioning to adult care, and the U.S. Food and Drug Administration regulatory perspective. Over 85 experts participated in the conference through information gathering and/or as presenters during the conference, and they reached several important conclusions. The most serious neurological impairments in PKU are preventable with current dietary treatment approaches. However, a variety of more subtle physical, cognitive, and behavioral consequences of even well-controlled PKU are now recognized. The best outcomes in maternal PKU occur when blood phenylalanine (Phe) concentrations are maintained between 120 and 360 μmol/L before and during pregnancy. The dietary management treatment goal for individuals with PKU is a blood Phe concentration between 120 and 360 μmol/L. The use of genotype information in the newborn period may yield valuable insights about the severity of the condition for infants diagnosed before maximal Phe levels are achieved. While emerging and established genotype-phenotype correlations may transform our understanding of PKU, establishing correlations with intellectual outcomes is more challenging. Regarding the use of sapropterin in PKU, there are significant gaps in predicting response to treatment; at least half of those with PKU will have either minimal or no response. A coordinated approach to PKU treatment improves long-term outcomes for those with PKU and facilitates the conduct of research to improve diagnosis and treatment. New drugs that are safe, efficacious, and impact a larger proportion of individuals with PKU are needed. However, it is imperative that treatment guidelines and the decision processes for determining access to treatments be tied to a solid evidence base with rigorous standards for robust and consistent data collection. The process that preceded the PKU State-of-the-Science Conference, the conference itself, and the identification of a research agenda have facilitated the development of clinical practice guidelines by professional organizations and serve as a model for other inborn errors of metabolism.

Variability in phenylalanine control predicts IQ and executive abilities in children with phenylketonuria

A number of studies have revealed significant relationships between cognitive performance and average phenylalanine (Phe) levels in children with phenylketonuria (PKU), but only a few studies have been conducted to examine the relationships between cognitive performance and variability (fluctuations) in Phe levels. In the current study, we examined a variety of indices of Phe control to determine which index best predicted IQ and executive abilities in 47 school-age children with early- and continuously-treated PKU. Indices of Phe control were mean Phe, the index of dietary control, change in Phe with age, and several indices of variability in Phe (standard deviation, standard error of estimate, and percentage of spikes). These indices were computed over the lifetime and during 3 developmental epochs (<5, 5.0-9.9, and ≥10 years of age). Results indicated that variability in Phe was generally a stronger predictor of cognitive performance than other indices of Phe control. In addition, executive performance was better predicted by variability in Phe during older than younger developmental epochs. These results indicate that variability in Phe should be carefully controlled to maximize cognitive outcomes and that Phe control should not be liberalized as children with PKU age.

Spatial propagation of protein polymerization

We consider the spatial dependence of filamentous protein self-assembly. Through studying the cases where the spreading of aggregated material is dominated either by diffusion or by growth, we derive analytical results for the spatial evolution of filamentous protein aggregation, which we validate against Monte Carlo simulations. Moreover, we compare the predictions of our theory with experimental measurements of two systems for which we identify the propagation as either growth or diffusion controlled. Our results connect the macroscopic observables that characterize the spatial propagation of protein self-assembly with the underlying microscopic processes and provide physical limits on spatial propagation and prionlike behavior associated with protein aggregation.

Tract-based evaluation of white matter damage in individuals with early-treated phenylketonuria

Previous research has documented white matter abnormalities in the brains of individuals with early-treated phenylketonuria (ETPKU). The majority of these past studies have relied on a region-based approach which focused on a limited number of spatially-defined regions within the brain. In the present study, we used diffusion tensor imaging (DTI) in conjunction with tract-based spatial statistics (TBSS) to perform an extensive examination of white matter tracts in the brains of ten individuals with ETPKU (mean age = 23.2 years) and 12 healthy non-PKU individuals (mean age = 23.5 years). Consistent with past research, we found that mean diffusivity (MD) was significantly restricted in the ETPKU group, and fractional anisotropy (FA) was comparable between the ETPKU and non-PKU groups. Moreover, we found restricted axial diffusivity (AD) and radial diffusivity (RD) in our ETPKU in numerous white matter tracts, suggesting widespread white matter compromise in ETPKU. In addition, this white matter pathology was more evident in older ETPKU participants with higher blood phenylalanine (phe) levels as compared to younger participants with lower phe levels.

White matter integrity and executive abilities following treatment with tetrahydrobiopterin (BH4) in individuals with phenylketonuria

Tetrahydrobiopterin (BH(4)) lowers blood phenylalanine (Phe) in individuals with PKU who are responders, but its effects on the brain and cognition have not been explored thoroughly. We examined blood Phe, microstructural white matter integrity, and executive abilities in 12 BH(4) responders before (i.e., baseline) and after (i.e., follow-up) six months of treatment with BH(4). Compared with baseline, Phe in these responders decreased by 51% during a 4 week screening period after initiation of treatment and remained lowered by 37% over the 6 month follow-up period. Significant improvements in white matter integrity, evaluated by mean diffusivity from diffusion tensor imaging, were also found following six months of treatment. Improvements in executive abilities were not identified, although six months may have been a period too brief for changes in cognition to follow changes in the brain. To our knowledge, our study is the first to explore relationships among Phe, white matter integrity, executive abilities, and BH(4) treatment within a single study.

The effects of tetrahydrobiopterin (BH4) treatment on brain function in individuals with phenylketonuria

Phenylketonuria (PKU) is a rare genetic condition characterized by an absence or mutation of the PAH enzyme, which is necessary for the metabolism of the amino acid phenylalanine into tyrosine. Recently, sapropterin dihydrochloride, a synthetic form of tetrahydrobiopterin (BH₄), has been introduced as a supplemental treatment to dietary phe control for PKU. Very little is known regarding BH₄ treatment and its effect on brain and cognition. The present study represents the first examination of potential changes in neural activation in patients with PKU during BH₄ treatment. To this end, we utilized an n-back working memory task in conjunction with functional magnetic resonance imaging (fMRI) to evaluate functional brain integrity in a sample of individuals with PKU at three timepoints: Just prior to BH₄ treatment, after 4 weeks of treatment, and after 6 months of treatment. Neural activation patterns observed for the PKU treatment group were compared with those of a demographically-matched sample of healthy non-PKU individuals who were assessed at identical time intervals. Consistent with past research, baseline evaluation revealed impaired working memory and atypical brain activation in the PKU group as compared to the non-PKU group. Most importantly, BH₄ treatment was associated with improvements in both working memory and brain activation, with neural changes evident earlier (4-week timepoint) than changes in working memory performance (6-month timepoint).

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We examine working memory and neural activation in patients with PKU at baseline.

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We track behavioral and neural changes related to BH4 treatment in the patients.

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BH4 treatment associated with improvement in neural activity at 4-week timepoint.

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BH4 treatment associated with improvement in working memory at 6-month timepoint.

Production and characterization of a trehalolipid biosurfactant produced by the novel marine bacterium Rhodococcus sp., strain PML026

AIMS

The aim of this study was to evaluate biosurfactant production by a novel marine Rhodococcus sp., strain PML026 and characterize the chemical nature and properties of the biosurfactant.

METHODS AND RESULTS

A novel marine bacterium (Rhodococcus species; strain PML026) was shown to produce biosurfactant in the presence of hydrophobic substrate (sunflower oil). Biosurfactant production (identified as a trehalolipid) was monitored in whole-batch cultures (oil layer and aqueous phase), aqueous phase (no oil layer) and filtered (0·2 μm) aqueous phase (no oil or cells; extracellular) and was shown to be closely associated with growth/biomass production. Extracellular trehalolipid levels increased postonset of stationary growth phase. Purified trehalolipid was able to reduce the surface tension of water to 29 mN m(-1) at Critical Micellar Concentration (CMC) of c. 250 mg l(-1) and produced emulsions that were stable to a wide range of conditions (pH 2-10, temperatures of 20-100°C and NaCl concentrations of 5-25% w/v). Separate chemical analyses of the intact trehalolipid and its constituents demonstrated the compound was in fact a mixture of homologues (>1180 MW) consisting of a trehalose moiety esterified to a series of straight chain and hydroxylated fatty acids.

CONCLUSIONS

The trehalolipid biosurfactant produced by the novel marine strain Rhodococcus sp. PML026 was characterized and exhibited high surfactant activity under a wide range of conditions.

SIGNIFICANCE AND IMPACT OF STUDY

Strain PML026 of Rhodococcus sp. is a potential candidate for bioremediation or biosurfactant production for various applications.

White matter integrity and executive abilities in individuals with phenylketonuria

Previous studies have revealed white matter abnormalities in the brains of individuals with phenylketonuria (PKU), but the microstructural nature of these abnormalities and their relationship to phenylalanine (Phe) levels and cognitive outcomes are poorly understood. In the current study, the microstructural integrity of white matter in 29 individuals with early-treated PKU and 12 healthy controls was examined using two complementary diffusion tensor imaging (DTI) approaches: region-of-interest (ROI) based analysis and voxel-wise tract based spatial statistics (TBSS) analysis. Relationships among DTI, executive abilities, and Phe level findings were explored. DTI revealed widespread lowering of mean diffusivity (MD) in the white matter of the PKU group in comparison with the control group. Executive abilities were also poorer for individuals with PKU than controls. Within the PKU group, lower MD was associated with higher Phe level and poorer executive abilities. These findings are the first to demonstrate the interplay among microstructural white matter integrity, executive abilities, and Phe control in individuals with PKU.

Processing speed and executive abilities in children with phenylketonuria

OBJECTIVE

Phenylketonuria (PKU) is a hereditary metabolic disorder that often results in neuropsychological impairment, even in individuals treated early and continuously. This study was conducted to examine processing speed, variability in processing speed, and the relationship between processing speed variables and executive abilities in children with early and continuously treated PKU.

METHOD

Participants were 42 children with PKU and 81 typically developing children from 7 to 18 years of age. Children completed 3 computerized reaction time (RT) tasks (simple RT, go/no-go, stimulus-response compatibility) and 7 tasks assessing executive abilities (working memory, inhibitory control, strategic processing).

RESULTS

Performance of children with PKU was significantly slower and more variable than that of controls across the 3 tasks administered. When age was considered, it was shown that processing speed improved with age to a comparable degree for both groups. Variability in processing speed, however, decreased more with age for the PKU than control group, reflecting the fact that variability in younger, but not older, children with PKU was greater than that of controls. With regard to executive abilities, processing speed and variability contributed to performance on most, but not all, executive tasks; and after controlling for processing speed and variability, executive impairments were still identified in working memory and inhibitory control (not strategic processing).

CONCLUSIONS

These findings indicate that information processing is slower and less efficient in children with PKU. In addition, processing speed and variability contribute to some, but not all, of the impairments in executive abilities observed in children with PKU.

A volumetric study of basal ganglia structures in individuals with early-treated phenylketonuria

Whereas the impact of early-treated phenylketonuria (ETPKU) on cortical white matter is well documented, relatively little is known regarding the potential impact of this metabolic disorder on deep gray matter structures such as the basal ganglia. The current study used high-resolution (1mm(3)) magnetic resonance imaging to investigate bilateral basal ganglia structures (i.e., putamen, caudate nucleus, and nucleus accumbens) in a sample of 13 individuals with ETPKU and a demographically-matched sample of 13 neurologically intact individuals without PKU. Consistent with previous research, we found smaller whole brain volumes in the ETPKU group compared with the non-PKU group. Individuals with ETPKU also had significantly larger putamen volumes than non-PKU individuals. In addition, the degree of putamen enlargement was correlated with blood phenylalanine levels and full scale IQ in the ETPKU group. These findings are consistent with the hypothesis that ETPKU-related increases in phenylalanine lead to decreased central dopamine levels thus impacting dopamine-dependent brain regions such as the putamen that play an important role in cognition.

Relationships between insulin sensitivity, skeletal muscle mass and muscle quality in obese adolescent boys

We examined the relationships between insulin sensitivity (IS), skeletal muscle (SM) mass and SM quality in youth. Forty obese adolescent boys (body mass index ≥ 95 th percentile, 12-18 years) participated in this study. IS and glucose tolerance was measured by a 3 h hyperinsulinemic-euglycemic clamp and a 2 h oral glucose tolerance test (OGTT), total SM mass and intermusular adipose tissue (IMAT) by whole-body magnetic resonance imaging, and muscular strength by one-repetition maximum leg and bench press. IMAT was associated (P<0.05) with IS (r=-0.53) and OGTT-insulin area under the curve (AUC; r=0.31). Similarly, muscular strength was associated (P<0.05) with both IS (r=0.39) and OGTT-insulin AUC (r=-0.32). By contrast, total SM mass was not associated with IS or any OGTT parameters (P>0.1). After accounting for race and tanner stage, IMAT and muscular strength remained significantly associated with IS, together explaining a total of 41% of the variance in IS. Our findings suggest that SM quality, but not SM mass, is associated with IS in obese adolescent boys.

Professional careers of graduates from one UK dental school

AIM

The aim of this study was to consider reported working patterns of dentists and retention of the dental workforce.

METHOD

Three cohorts of dental graduates from the University of Birmingham (n = 505) were tracked using the General Dental Council (GDC) register to assess retention of the workforce. A questionnaire was sent to these graduates to explore changes in working patterns over time and to investigate the factors which had influenced their choice of job location.

RESULTS

A high proportion (90.9%) of the dental graduates included in this tracking exercise were found on the GDC register on the census date. A slightly higher proportion of female graduates (10.3%) than male graduates (8.0%) could not be traced on the current register (p = 0.37). A change in working patterns over time was demonstrated, with more general dental practitioners reporting a shorter working week. 'Availability of jobs' was the factor reported by most respondents to be important in determining job location.

CONCLUSION

This study provides evidence of changing work patterns over time. Furthermore, although the majority of the study sample remained on the GDC register, there appeared to have been a gradual loss of subjects from the dental workforce over time. Changes such as these may affect the provision of services and the impact of investment in training. Further research in this area is warranted.

Decreased functional brain connectivity in individuals with early-treated phenylketonuria: evidence from resting state fMRI

Previous histological and neuroimaging studies have documented structural abnormalities in the white matter of the brain in individuals with early-treated phenylketonuria (ETPKU). It remains unclear, however, the extent to which the function of the brain's interconnections are impacted by this condition. Presently, we utilized functional magnetic resonance imaging (fMRI) to evaluate the synchronization of neural signals (i.e., functional connectivity) among brain regions comprising the default mode network (DMN) in a sample of 11 individuals with ETPKU and 11 age- and gender-matched neurologically intact controls. The DMN is a group of interconnected brain regions that are known to be generally more active during rest than during task performance. Data analysis revealed decreased functional connectivity among DMN regions for the ETPKU group compared with the control group. Within the PKU group, we also found a significant relationship between blood phenylalanine (phe) levels and the functional connectivity between select regions of the DMN. In conjunction with findings from another recent fMRI study (Christ, Moffitt et al. 2010), the present results suggest that ETPKU-related deficiencies in functional connectivity are pervasive. The current findings also provide initial evidence that the extent of such impairment may be moderated in part by blood phe levels.

Assessing executive abilities following acute stroke with the trail making test and digit span

The Trail Making Test and Digit Span are neuropsychological tests widely used to assess executive abilities following stroke. The Trails B and Digits Backward conditions of these tests are thought to be more sensitive to executive impairment related to frontal lobe dysfunction than the Trails A and Digits Forward conditions. Trails B and Digits Backward are also thought to be more sensitive to brain damage in general. Data from the Stroke and Lesion Registry maintained by the Washington University Cognitive Rehabilitation Research Group were analyzed to compare the effects of frontal versus nonfrontal strokes and to assess the effects of stroke severity. Results showed that the performance of patients with frontal and nonfrontal strokes was comparable in each condition of both the Trail Making Test and Digit Span, providing no support for the widely held belief that Trails B and Digits Backward are more sensitive to frontal lobe damage. Further, Trails A was as strongly correlated with stroke severity as Trails B, whereas Digits Backward was more strongly correlated with stroke severity than Digits Forward. Overall, the Trail Making Test and Digit Span are sensitive to brain damage but do not differentiate between patients with frontal versus nonfrontal stroke.

Mapping the development of response inhibition in young children using a modified day-night task

Response inhibition was examined in 40 children 3½ to 8 years of age using a modified day-night task. Performance in a neutral condition explained variance in congruent and incongruent conditions, indicating that age-related improvements in these latter conditions were partly mediated by working memory and processing speed. After controlling for neutral performance, age did not explain variance in congruent performance but explained variance in incongruent performance. These findings indicate that the associative strength between pictures and labels used in the task is age invariant and that older children are better than younger children at inhibiting responses to these associations.

A latent variables examination of processing speed, response inhibition, and working memory during typical development

This study addressed three related aims: (a) to replicate and extend previous work regarding the nonunitary nature of processing speed, response inhibition, and working memory during development; (b) to quantify the rate at which processing speed, response inhibition, and working memory develop and the extent to which the development of these latter abilities reflect general changes in processing speed; and (c) to evaluate whether commonly used tasks of processing speed, response inhibition, and working memory are valid and reliable when used with a developmentally diverse group. To address these aims, a latent variables approach was used to analyze data from 147 participants 6-24years of age. Results showed that processing speed, response inhibition, and working memory were separable abilities and that the extent of this separability was stable across the age range of participants. All three constructs improved as a function of age; however, only the effect of age on working memory remained significant after processing speed was controlled. The psychometric properties of tasks used to assess the constructs were age invariant, thereby validating their use in studies of executive development.

Executive strategic processing during verbal fluency performance in children with phenylketonuria

In the current study, we examined a specific aspect of executive abilities, strategic processing, in 32 children with early-treated phenylketonuria (PKU) and 41 typically-developing control children. To do so, clustering and switching were assessed during semantic (animal, food/drink) and phonemic (S, F) fluency tasks. Specifically, number of words generated, number of subcategory clusters, number of words in subcategory clusters, and number of switches between subcategories were analyzed to provide a refined analysis of strategic processing. Compared with controls, children with PKU generated significantly fewer words and made significantly fewer switches between subcategories in the food/drink trial and the phonemic fluency condition. Number of switches was associated with number of words generated in these tasks. In addition, a significant interaction between age and group in number of switches for the food/drink trial reflected a greater increase in number of switches for the control than PKU group as a function of increasing age. These results suggest impairment in frontally-mediated aspects of strategic processing in children with early-treated PKU and indicate that strategic processing should be evaluated carefully as these children age.

Executive function in early-treated phenylketonuria: profile and underlying mechanisms

Despite early and continuous dietary intervention, individuals with early-treated phenylketonuria (PKU) experience significant neurocognitive sequelae. An area of cognitive ability that is believed to be particularly affected is executive function (EF). This paper provides a critical review of the evidence for EF impairment in early-treated PKU within the context of recent advances in neuropsychological theory and research. The most consistent findings of PKU-related EF impairment were in executive working memory and prepotent response inhibition. Surprisingly, findings on shifting ability and other more complex aspects of EF were largely equivocal. Cohort (e.g., age, phenylalanine (Phe) levels) and task (e.g., standard clinical versus experimental tasks) related differences likely contributed to the variability in findings reported by these studies. Day-to-day EF also appears to be impaired although the precise pattern of impairment remains unclear, as does the relationship between laboratory measures of EF and questionnaires assessing day-to-day EF. Similarly, whereas several studies have found a relationship between Phe levels and EF, the best predictor variable (e.g., concurrent Phe level, lifetime Phe level, Phe level variability) of current EF performance varied from study to study. Neurologic compromise related to dopamine deficiency, white matter abnormalities, and disruptions in functional connectivity likely underlies the EF impairments described in this review. In closing, this review identifies remaining unanswered questions and future avenues for research.

Screening for cognitive and social-emotional problems in individuals with PKU: tools for use in the metabolic clinic

Cognitive deficits, learning difficulties, and emotional problems occur at significantly higher rates in individuals with phenylketonuria (PKU) than in the general population. The relationship between elevated blood phenylalanine (Phe) levels and the severity of these problems often remain unrecognized. Children and adults with PKU require ongoing screening so that referrals to psychologists or psychiatrists familiar with metabolic disorders can be made when necessary for in-depth evaluation and treatment. To identify screening instruments that can be used by non-psychologists as well as psychologists, a group of 10 psychologists and a psychiatrist in the United States with expertise in neuropsychological assessment and PKU proposed a Uniform Assessment Method for PKU. Questionnaires were selected that reliably detect problems in adaptive behavior, executive function, and emotional well-being, representing the most vulnerable areas for individuals with PKU. These questionnaires are appropriate for individuals from infancy through adulthood, may be administered in less than 1h, have computerized scoring accessibility, have no practice effects, and are available in Spanish and English. In addition to assessing function at a single point in time, the screening measures may be administered at each clinic visit to assess changes in function related to metabolic status or treatment (e.g., Phe-restricted diet, food supplements). The following questionnaires comprise the Uniform Assessment Method for PKU: for 0-2 years, Adaptive Behavior Assessment System-Second Edition (ABAS-II); for 2-17 years, Behavior Rating Inventory of Executive Function (BRIEF) and Behavior Assessment System for Children-Second Edition (BASC-II); and for adults, BRIEF, Beck Anxiety Inventory (BAI), and Beck Depression Inventory-Second Edition (BDI-II). In addition to long-term monitoring of outcomes in PKU, this uniform screening approach facilitates PKU research, as data may be pooled across multiple clinics using a consistent battery of assessment measures.

A comparison of Personal Dental Service (PDS) and General Dental Service (GDS) patients in terms of reported interventions, oral health and dentists' perceptions

AIMS

The aim of the study was to investigate the reported working patterns, dentist perceptions and patient oral health for dentists in a Personal Dental Services (PDS) pilot and compare this with that of matched dentists working in the General Dental Services (GDS) arrangements in the same part of England.

METHOD

Ten dentists were recruited, five each from PDS and GDS practices in Warwickshire, UK. The number of interventions carried out for adult patients in the year to April 2003 was obtained from the Dental Practice Board (DPB) for the two groups and compared. An Oral Health Index (OHX) (Burke and Wilson, 1995) was used to determine the oral health of a selection of patients from the two groups of dentists in the study. The final stage of the study involved semi-structured interviews with the dentists.

RESULTS

The average age of dentists was similar, in the early to mid 40's (p>0.05). Both groups were, on average, around 20 years post qualification. The GDS dentists made an average of 3,507 activity reports to the Dental Practice Board in the year examined, compared with 3,441 from the PDS dentists. PDS dentists provided fewer simple periodontal treatments than GDS dentists, but otherwise the pattern of reported activity was similar. Both PDS and GDS dentists suggested that GDS dentists carried out more fillings because of a perverse incentive to provide fillings compared with PDS arrangements. PDS dentists believed that their treatment profiles had not changed significantly since changing to PDS, and suggested that their prescribing was based on clinical need only and was not influenced by the remuneration system. A total of 225 OHX scores were obtained for patients attending PDS dentists and a further 214 from patients attending GDS dentists. Overall, the mean OHX score was lower in the GDS patients than for PDS patients.

CONCLUSIONS

PDS dentists provided fewer simple periodontal treatments than their GDS counterparts. There was no difference in the oral health of patients treated under either system. Although there was some evidence of a difference in attitude between GDS and PDS dentists towards charging and claiming for simple periodontal treatment, there was no uniformity of opinion within either group. There would appear to be a number of complex factors impacting upon decisions to treat or monitor dental conditions.

Lateralizing seizure focus in presurgical patients with temporal lobe epilepsy: utility of the Ruff-Light Trail Learning Test

From a neuropsychological perspective, left or right temporal lobe abnormalities underlying seizures in patients with temporal lobe epilepsy (TLE) are thought to contribute to selective deficits in verbal or nonverbal memory abilities, respectively. The Ruff-Light Trail Learning Test (RULIT) is specifically designed to detect right hemisphere dysfunction. The purpose of our study was to examine the utility of the RULIT in distinguishing between patients with right (n=20) and patients with left (n=32) TLE in presurgical evaluations. We identified a significant between-group difference in RULIT scores, but not in the expected direction; that is, patients with right TLE had significantly better scores than patients with left TLE. These findings indicate that the RULIT may not be an appropriate test for presurgical epilepsy evaluations. Findings are discussed within the context of results from other lateralizing neuropsychological tests.

Response monitoring in children with phenylketonuria

Phenylketonuria (PKU) is characterized by a disruption in the metabolism of phenylalanine and is associated with dopamine deficiency (Diamond, Prevor, Callender, & Druin, 1997) and cerebral white matter abnormalities (e.g., Anderson et al., 2007). From a neuropsychological perspective, prefrontal dysfunction is thought to underlie the deficits in executive abilities observed in individuals with PKU (Christ, Steiner, Grange, Abrams, & White, 2006; Diamond et al., 1997; White, Nortz, Mandernach, Huntington, & Steiner, 2001, 2002). The purpose of our study was to examine a specific aspect of executive ability, response monitoring, as measured by posterror slowing. The authors examined posterror reaction time (RT) in 24 children with well-controlled, early treated PKU and 25 typically developing control children using a go/no-go task. Results showed that RTs of both controls and children with PKU slowed significantly following the commission of errors. The magnitude of posterror slowing, however, was significantly less for children with PKU. These findings indicate deficient response monitoring in children with PKU.

Blood transfusion therapy is feasible in a clinical trial setting in children with sickle cell disease and silent cerebral infarcts

BACKGROUND

Silent cerebral infarcts are both morbid and progressive in children with sickle cell disease (SCD). While blood transfusion therapy is effective primary and secondary stroke prevention, the efficacy and acceptance of blood transfusion therapy for children with silent cerebral infarcts is unknown. The overall goals of this study were to determine the feasibility and short-term efficacy of blood transfusion therapy for silent cerebral infarcts.

PROCEDURE

We conducted a single-arm feasibility intervention study. Children with SCD and silent cerebral infarcts received blood transfusion therapy. Short-term efficacy was defined as no progression of MRI findings on repeat MRI.

RESULTS

Ten children enrolled in the study, and nine were evaluable. Five were male. The average age was 10.0 years (range 3.1-16.8). Seven of nine completed the transfusion therapy for over 2 years, with an average duration of therapy of 2.7 years (range 1-6). Twenty infarcts and four cases of Moya Moya were present on the initial MRI. Seven of nine subjects had repeat MRIs. Of these seven, there were a total of 18 infarcts. One infarct increased in size and one case of Moya Moya progressed on repeat MRI. All other lesions were stable or became smaller in diameter while on transfusion therapy during the time of follow up (mean 3.9 years, range 2.1-5.7).

CONCLUSIONS

Blood transfusion therapy is a feasible therapy for the prevention of progression of silent cerebral infarcts.

Inhibitory control in children with autism spectrum disorder

Impairments in executive abilities such as cognitive flexibility have been identified in individuals with autism spectrum disorder (ASD). It remains unclear, however, whether such individuals also experience impairments in another executive ability: inhibitory control. In the present study, we administered three inhibitory tasks to 18 children with ASD, 23 siblings of children with ASD, and 25 typically developing children. After controlling for individual differences in age, overall IQ, and processing speed, children with ASD demonstrated impaired performance on two of the three inhibitory tasks. Results suggest that children with ASD experience circumscribed deficits in some but not all aspects of inhibitory control. More generally, the findings underscore the importance of using multiple measures to assess a putative single cognitive ability.

The BDA Dental Academic Staff Group Student Elective Workshop

In the current climate in dental education, many schools are re-evaluating the role of the student elective in the curriculum, with two schools no longer running elective programmes. In order to discuss the future of student electives in the dental curriculum, the Dental Academic Staff Group (DASG) of the British Dental Association organised a Student Elective Workshop, which attracted 42 delegates including nine student representatives. The following article is an account of the Workshop and its conclusions.

A pilot randomized education rehabilitation trial is feasible in sickle cell and strokes

A randomized trial was completed to assess the feasibility of a 2-year education rehabilitation program for students with sickle cell disease and memory deficits. Eleven students were assigned to tutoring with or without memory training for 2 years. Eighty-two percent completed the program. Evidence of improvement in memory and academic achievement existed. Educational rehabilitation is a feasible strategy, but further investigation is needed to assess the benefit in a multi center trial.

Consent and school-based surveys

Possession of information on population health needs is at the heart of the commissioning process. The move to local commissioning arrangements for all NHS dental services makes this particularly relevant for dentistry. High response rates in surveys are necessary for the results to be sufficiently valid to inform commissioning decisions. Our recent experience in organising and undertaking school-based epidemiological surveys has demonstrated an increasing problem with recruiting subjects of all ages. This has significant implications for dental epidemiological surveys in the future.

Inhibitory Control in Children with Frontal Infarcts Related to Sickle Cell Disease

Evidence from past studies indicates that children with traumatic brain injury experience difficulties with inhibitory control. Less is known about inhibitory control in children with frontal brain injury related to cerebral infarction. We compared the inhibitory performance of children with frontal infarcts related to sickle cell disease with that of a control group of children with sickle cell disease but no history of cerebral infarction. On a stimulus-response reversal task, children with frontal infarcts made significantly more accuracy errors in the inhibitory condition than controls. Findings from this study and from previous research suggest that impairments in inhibitory control are common following frontal injury in a range of pediatric populations.