The potential for epigenetic analysis of paediatric CNS tumours to improve diagnosis, treatment and prognosis.

Tumours of central nervous system (CNS) origin are the second most prevalent group of cancers in children, yet account for the majority of childhood cancer-related deaths. Such tumours show diverse location, cell type of origin, disease course and long-term outcome, both across and within tumour types, making treatment problematic and contributing to the relatively modest progress in reducing mortality over recent decades. As technological advances begin to reveal the genetic landscape of all cancers, it is becoming increasingly clear that genetic disruption represents only one 'layer' of molecular disruption associated with disease aetiology. Obtaining a full understanding of tumour behaviour requires an understanding of the cellular and molecular pathways disrupted during tumourigenesis, particularly in relation to gene expression. The utility of such an approach has allowed stratification of cancers such as medulloblastoma into subgroups based on molecular features, with potential to refine risk prediction. Given that epigenetic disruption is a universal feature of all human cancers, it is logical to speculate that interrogating epigenetic marks may help to further define the molecular profile, and therefore the clinical trajectory, of tumours. An integrated approach to build a molecular 'signature' of individual tumours that incorporates traditional morphological and demographic information, genetic and transcriptome analysis, in addition to epigenomics (DNA methylation and non-coding RNA analysis), offers tremendous promise to (i) inform treatment approach, (ii) facilitate accurate early identification (preferably at diagnosis) of variable risk groups (both good and poor prognosis groups), and (iii) track disease progression in childhood CNS tumours.

Are forensic scientists too risk averse?

Fingerprint examiners maintain decision thresholds that represent the amount of evidence required for an identification or exclusion conclusion. As measured by error rate studies (Proc Natl Acad Sci USA. 2011;108(19):7733-8), these decision thresholds currently exhibit a preference for preventing erroneous identification errors at the expense of preventing erroneous exclusion errors. The goal of this study is to measure the decision thresholds for both fingerprint examiners and members of the general public, to determine whether examiners are more risk averse than potential jury members. To externally measure these decision thresholds, subjects manipulated decision criteria in a web-based visualization that reflects the trade-offs between erroneous identification decisions and erroneous exclusion decisions. Data from fingerprint examiners and the general public were compared to determine whether both groups have similar values as expressed by the placement of the decision criteria. The results of this study show that fingerprint examiners are more risk averse than members of the general public, although they align with error rate studies of fingerprint examiners. Demographic data demonstrate those factors that may contribute to differences in decision criterion placement, both between the two groups and between individuals within a group. The experimental methods provide a rich framework for measuring, interpreting, and responding to the values of society as applied to forensic decision-making.

Perforin-mediated cytotoxicity is critical for surveillance of spontaneous lymphoma.

Immune surveillance by cytotoxic lymphocytes against cancer has been postulated for decades, but direct evidence for the role of cytotoxic lymphocytes in protecting against spontaneous malignancy has been lacking. As the rejection of many experimental cancers by cytotoxic T lymphocytes and natural killer cells is dependent on the pore-forming protein perforin (pfp), we examined pfp-deficient mice for increased cancer susceptibility. Here we show that pfp-deficient mice have a high incidence of malignancy in distinct lymphoid cell lineages (T, B, NKT), indicating a specific requirement for pfp in protection against lymphomagenesis. The susceptibility to lymphoma was accentuated by simultaneous lack of expression of the p53 gene, mutations in which also commonly predispose to human malignancies, including lymphoma. In contrast, the incidence and age of onset of sarcoma was unaffected in p53-deficient mice. Pfp-deficient mice were at least 1,000-fold more susceptible to these lymphomas when transplanted, compared with immunocompetent mice in which tumor rejection was controlled by CD8(+) T lymphocytes. This study is the first that implicates direct cytotoxicity by lymphocytes in regulating lymphomagenesis.

Predicting Ischemic Risk Using Blood Oxygen Level-Dependent MRI in Children with Moyamoya.

BACKGROUND AND PURPOSE: Moyamoya is a progressive steno-occlusive arteriopathy. MR imaging assessment of cerebrovascular reactivity can be performed by measuring the blood oxygen level-dependent cerebrovascular reactivity response to vasoactive stimuli. Our objective was to determine whether negative blood oxygen level-dependent cerebrovascular reactivity status is predictive of ischemic events in childhood moyamoya. MATERIALS AND METHODS: We conducted a retrospective study of a consecutive cohort of children with moyamoya who underwent assessment of blood oxygen level-dependent cerebrovascular reactivity. The charts of patients with written informed consent were reviewed for the occurrence of arterial ischemic stroke, transient ischemic attack, or silent infarcts. We used logistic regression to calculate the OR and 95% CI for ischemic events based on steal status. Hazard ratios for ischemic events based on age at blood oxygen level-dependent cerebrovascular reactivity imaging, sex, and moyamoya etiology were calculated using Cox hazards models. RESULTS: Thirty-seven children (21 female; median age, 10.7 years; interquartile range, 7.5-14.7 years) were followed for a median of 28.8 months (interquartile range, 13.7-84.1 months). Eleven (30%) had ischemic events, 82% of which were TIA without infarcts. Steal was present in 15 of 16 (93.8%) hemispheres in which ischemic events occurred versus 25 of 58 (43.1%) ischemic-free hemispheres (OR = 19.8; 95% CI, 2.5-160; P = .005). Children with idiopathic moyamoya were at significantly greater risk of ischemic events (hazard ratio, 3.71; 95% CI, 1.1-12.8; P = .037). CONCLUSIONS: Our study demonstrates that idiopathic moyamoya and the presence of steal are independently associated with ischemic events. The use of blood oxygen level-dependent cerebrovascular reactivity could potentially assist in the selection of patients for revascularization surgery and the direction of therapy in children with moyamoya.

The Utility of Expanded Conclusion Scales During Latent Print Examinations.

During fingerprint comparisons, a latent print examiner visually compares two impressions to determine whether or not they originated from the same source. They consider the amount of perceived detail in agreement or disagreement and accumulate evidence toward same source and different sources propositions. This evidence is then mapped to one of three conclusions: Identification, Inconclusive, or Exclusion. A limitation of this 3-conclusion scale is it can lose information when translating the conclusion from the internal strength-of-evidence value to one of only three possible conclusions. An alternative scale with two additional values, support for different sources and support for common sources, has been proposed by the Friction Ridge Subcommittee of OSAC. The expanded scale could lead to more investigative leads but could produce complex trade-offs in both correct and erroneous identifications. The aim of the present study was to determine the consequences of a shift to expanded conclusion scales in latent print comparisons. Latent print examiners each completed 60 comparisons using one of the two scales, and the resulting data were modeled using signal detection theory to measure whether the expanded scale changed the threshold for an "Identification" conclusion. When using the expanded scale, examiners became more risk-averse when making "Identification" decisions and tended to transition both the weaker Identification and stronger Inconclusive responses to the "Support for Common Source" statement. The results demonstrate the utility of an expanded conclusion scale and also provide guidance for the adoption of these or similar scales.

Left ventricular receptors inhibit brain serotonin neurons during coronary artery occlusion.

Acute coronary artery ligation in pargyline-treated rats decreased serotonin and increased 5-hydroxyindoleacetic acid in the medulla and posterior hypothalamus. Lidocaine applied topically to the left ventricle completely prevented these alterations. No changes in serotonin were observed in the other brain regions examined. These data suggest a reflex inhibition of bulbar and hypothalamic serotonergic nerves by left ventricular receptors following acute coronary artery occlusion in the rat.

A new method of spike modelling and interval analysis.

Here we develop a new model of spike firing, based on the leaky integrate and fire model, modified to simulate afterpotentials. We also develop new analysis techniques, applying these to recorded and model generated data in order to make a comparative analysis and develop the model as a hypothesis for the functional components of the neuron. The model is based in this first instance on hypothalamic oxytocin neurons. We demonstrate how model parameters and cell properties relate to features observed in inter-spike intervals histograms, and the limits of these in being able to detect patterning features in spike recordings. A new technique, spike train analysis, is able to detect previously unobserved patterning, showing a dependence of spike intervals on previous firing activity. This effect is reproduced in the model by adding the small amplitude but long lasting after hyper-polarising potential (AHP). A fit measure based on log likelihood is used to compare model generated data to recorded spike intervals, taking account of interval dependence on previous activity. This measure is used with the simplex multiple parameter search algorithm to develop an automated method for fitting the model to recorded data.

Upper limb motor function in young adults with spina bifida and hydrocephalus.

OBJECTIVE: The objective of the study was to measure upper limb motor function in young adults with spina bifida meningomyelocele (SBM) and typically developing age peers. METHOD: Participants were 26 young adults with SBM, with a Verbal or Performance IQ score of at least 70 on the Wechsler scales, and 27 age- and gender-matched controls. Four upper limb motor function tasks were performed under four different visual and cognitive challenge conditions. Motor independence was assessed by questionnaire. RESULTS: Fewer SBM than control participants obtained perfect posture and rebound scores. The SBM group performed less accurately and was more disrupted by cognitive challenge than controls on limb dysmetria tasks. The SBM group was slower than controls on the diadochokinesis task. Adaptive motor independence was related to one upper limb motor task, arm posture, and upper rather than lower spinal lesions were associated with less motor independence. CONCLUSIONS: Young adults with SBM have significant limitations in upper limb function and are more disrupted by some challenges while performing upper limb motor tasks. Within the group of young adults with SBM, upper spinal lesions compromise motor independence more than lower spinal lesions.

Quantifying the ossification of the carpus in skeletal age estimation: Radiographic standards for Australian subadults.

An evaluation of the development of a child's skeleton and estimation of bone age provides an insight into a child's overall maturation. This study aimed to introduce a contemporary method for assessing bone age of Australian children using formulae incorporating carpal areal measurements. The standards introduced in this study can be used to assess the developmental status of Australian children who may be affected by growth-related illnesses. Additionally, in situations where the living age of a subadult is unknown, methodologies to accurately estimate age are required, particularly in the Western world where knowledge of the age of an individual is necessary for legal reasons. The sample consisted of retrospective hand and wrist radiographs acquired from 541 children (females: 246, males: 295) aged from birth to 20 years. Using the DICOM viewer Weasis, the carpal area ratio (B.Ar/T.Ar) was calculated for each individual radiograph by measuring the carpal bone area (B.Ar) and total tissue area of the carpus (T.Ar). A changepoint regression model demonstrated that the model constructed in this study was the most accurate in the younger age groups and was able to accurately determine whether a child was under 12 years if female and 13 years if male. A rapid acceleration of growth was observed at approximately 12-13 years in our sample, which may represent the onset of the pubertal growth spurt; this resulted in a high data variance and low model prediction accuracy in female and male children older than 12 and 13 years, respectively.

Absence of retroviral vector-mediated transformation of gene-modified T cells after long-term engraftment in mice.

There is considerable concern regarding the transforming potential of retroviral vectors currently used for gene therapy, with evidence that retroviral integration can lead to leukemia in recipients of gene-modified stem cells. However, it is not clear whether retroviral-mediated transduction of T cells can lead to malignancy. We transduced mouse T cells with a Moloney murine retroviral gene construct and transferred them into congenic mice, which were preconditioned to enhance the engraftment of transferred T cells. Recipients were then observed long-term for evidence of cancer. Transferred T cells persisted in mice throughout life at levels up to 17% with gene copy numbers up to 5.89 x 10(5) per million splenocytes. Mice receiving gene-modified T cells developed tumors at a similar rate as control mice that did not receive T cells, and tumors in both groups of mice were of a similar range of histologies. Hematological malignancies comprised approximately 60% of cancers, and the remaining cancers consisted largely of carcinomas. Importantly, the incidence of lymphomas was similar in both groups of mice, and no lymphomas were found to be of donor T-cell origin. This study indicates that the use of retroviral vectors to transduce T cells does not lead to malignant transformation.

PPARG locus haplotype variation and exacerbations in asthma.

The peroxisome proliferator-activated receptor gamma (PPARgamma) regulates inflammation and may play a role in asthma. Using mouthwash-derived DNA and clinical interviews and measurements, we investigated the association of previously characterized single-nucleotide polymorphisms in the PPARG gene (Pro12Ala, C1431T, and C-681G) with asthma exacerbations in patients aged 3-22 years (n=569). The common homozygous haplotype combination of the Pro12 and C1431 alleles was associated with increased risk for asthma exacerbations (ProC, odds ratio (OR) 1.87, 95% confidence interval 1.25-2.79; P=0.002). The ProC genotype was associated with increased school absences (OR 1.82, 95% confidence interval 1.21-2.76; P=0.004) and hospital admissions (OR 2.32, 95% confidence interval 1.18-4.58; P=0.015) over the preceding 6 months. The population-attributable risk of this genotype was 33%. Common genetic variation at the PPARG locus may play an important role in modulating the long-term control of asthma in children and young adults.

Biopterin synthesis defect. Treatment with L-dopa and 5-hydroxytryptophan compared with therapy with a tetrahydropterin.

We have identified a generalized deficiency of monoamine neurotransmitters in a patient with a defect in biopterin synthesis. Neurotransmitter precursors (L-3,4-dihydroxyphenylalanine [L-dopa]; 5-hydroxytryptophan [5-HTP] and a tetrahydropterin [6-methyltetrahydropterin (6MPH4)] were investigated for their ability to normalize monoamine neurotransmitter metabolism. Before treatment, the concentrations of dopamine (DA), norepinephrine, epinephrine, and six monoamine metabolites were very low or undetectable in plasma, cerebrospinal fluid, or urine. L-Dopa and 5-HTP replacement was begun at age 7 mo. This therapy generally corrected the deficiency of monoamines and their metabolites, and improved neurological development until the age of 25 mo. Despite these benefits, the intermittent administration of L-dopa could not produce a stable improvement of acute neurological function or DA metabolism. In the 3 h after L-dopa administration, plasma DA and the motor activity and alertness of the patient rose and fell in parallel. Doses of L-dopa that were clinically optimal produced normal plasma levels of norepinephrine and epinephrine, but excessive concentrations of DA and its metabolites. Furthermore, the clinical and biochemical effects of L-dopa were inhibited by phenylalanine and 5-HTP, respectively, demonstrating that these amino acids have antagonistic pharmacological effects. Physiological correction of the monoamine deficit and the hyperphenylalaninemia of this disorder was attempted at age 35 mo using high doses (8-38 mg/kg per d) of 6MPH4. 6MPH4, a synthetic analogue of tetrahydrobiopterin, controlled the hyperphenylalaninemia. Significant concentrations of 6MPH4 were obtained in the cerebrospinal fluid; no neurological improvement or stimulation of monoamine synthesis in the central nervous system was detected. These findings indicate the complexity in replacement therapy with L-dopa and 5-HTP, but suggest that this treatment may be partially effective in biopterin-deficient patients who are unresponsive to high doses of tetrahydropterins.

Holistic processing of fingerprints by expert forensic examiners.

Holistic processing is often characterized as a process by which objects are perceived as a whole rather than a compilation of individual features. This mechanism may play an important role in the development of perceptual expertise because it allows for rapid integration across image regions. The present work explores whether holistic processing is present in latent fingerprint examiners, who compare fingerprints collected from crime scenes against a set of standards taken from a suspect. We adapted a composite task widely used in the face recognition and perceptual expertise literatures, in which participants were asked to match only a particular half of a fingerprint with a previous image while ignoring the other half. We tested both experts and novices, using both upright and inverted fingerprints. For upright fingerprints, we found weak evidence for holistic processing, but with no differences between experts and novices with respect to holistic processing. For inverted fingerprints, we found stronger evidence of holistic processing, with weak evidence for differences between experts and novices. These relatively weak holistic processing effects contrast with robust evidence for holistic processing with faces and with objects in other domains of perceptual expertise. The data constrain models of holistic processing by demonstrating that latent fingerprint experts and novices may not substantively differ in terms of the amount of holistic processing and that inverted stimuli actually produced more evidence for holistic processing than upright stimuli. Important differences between the present fingerprint stimuli and those in the literature include the lack of verbal labels for experts and the absence of strong vertical asymmetries, both of which might contribute to stronger holistic processing signatures in other stimulus domains.

Oxytocin Neurones: Intrinsic Mechanisms Governing the Regularity of Spiking Activity.

Oxytocin neurones of the rat supraoptic nucleus are osmoresponsive and, with all other things being equal, they fire at a mean rate that is proportional to the plasma sodium concentration. However, individual spike times are governed by highly stochastic events, namely the random occurrences of excitatory synaptic inputs, the probability of which is increased by increasing extracellular osmotic pressure. Accordingly, interspike intervals (ISIs) are very irregular. In the present study, we show, by statistical analyses of firing patterns in oxytocin neurones, that the mean firing rate as measured in bins of a few seconds is more regular than expected from the variability of ISIs. This is consistent with an intrinsic activity-dependent negative-feedback mechanism. To test this, we compared observed neuronal firing patterns with firing patterns generated by a leaky integrate-and-fire model neurone, modified to exhibit activity-dependent mechanisms known to be present in oxytocin neurones. The presence of a prolonged afterhyperpolarisation (AHP) was critical for the ability to mimic the observed regularisation of mean firing rate, although we also had to add a depolarising afterpotential (DAP; sometimes called an afterdepolarisation) to the model to match the observed ISI distributions. We tested this model by comparing its behaviour with the behaviour of oxytocin neurones exposed to apamin, a blocker of the medium AHP. Good fits indicate that the medium AHP actively contributes to the firing patterns of oxytocin neurones during non-bursting activity, and that oxytocin neurones generally express a DAP, even though this is usually masked by superposition of a larger AHP.

Specific targeting, biodistribution, and lack of immunogenicity of chimeric anti-GD3 monoclonal antibody KM871 in patients with metastatic melanoma: results of a phase I trial.

PURPOSE: KM871 is a chimeric monoclonal antibody against the ganglioside antigen GD3, which is highly expressed on melanoma cells. We conducted an open-label, dose escalation phase I trial of KM871 in patients with metastatic melanoma. PATIENTS AND METHODS: Seventeen patients were entered onto one of five dose levels (1, 5, 10, 20, and 40 mg/m2). Patients received three infusions of KM871 at 2-week intervals, with the first infusion of KM871 trace-labeled with indium-111 (111In) to enable assessment of biodistribution in vivo. Biopsies of metastatic melanoma sites were performed on days 7 to 10. RESULTS: Fifteen of 17 patients completed a cycle of three infusions of KM871. No dose-limiting toxicity was observed during the trial; the maximum-tolerated dose was therefore not reached. Three patients (at the 1-, 5-, and 40-mg/m2 dose levels) developed pain and/or erythema at tumor sites consistent with an inflammatory response. No normal tissue uptake of 111In-KM871 was observed, and tumor uptake of 111In-KM871 was observed in all lesions greater than 1.5 cm (tumor biopsy 111KM871 uptake results: range, 0.001% to 0.026% injected dose/g). The ratio of maximum tumor to normal tissue was 15:1. Pharmacokinetic analysis revealed a 111In-KM871 terminal half-life of 7.68 +/- 2.94 days. One patient had a clinical partial response that lasted 11 months. There was no serologic evidence of human antichimeric antibody in any patient, including one patient who received 16 infusions over a 12-month period. CONCLUSION: This study is the first to demonstrate the biodistribution and specific targeting of an anti-GD3 antibody to metastatic melanoma in patients. The long half-life and lack of immunogenicity of KM871 makes this antibody an attractive potential therapy for patients with metastatic melanoma.

Adoptive transfer of insulitis and diabetes in neonates of diabetes-prone and -resistant rats. Tissue localization of injected blasts.

Intravenous transfusion of concanavalin A-activated splenic cells from acutely diabetic BB or diabetic BB/hooded hybrid donor rats into 6- to 36-h-old neonate recipients of diabetes-prone and -resistant rat lines induced insulitis and in some severe diabetes. These effects were observed 10-20 days after the injection of the blasts. Focal lesions of insulitis were absent in neonates killed 1 and 3 days after the blast injection but were observed in neonates killed on the 5th and 8th day. As determined by autoradiography after the injection of [3H]thymidine-labeled blasts, numerous blast cells migrated and settled in various immature lymph nodes and in the spleen within 24 h after injection. Focal mononuclear infiltrations in the islets containing labeled and unlabeled cells were again observed on the 5th and 8th day but not on the 1st and 3rd day after injection. These experiments indicate that target-specific blasts undergo a short phase of proliferation and maturation in lymphoid organs of the recipients, before initiating the autoimmune process in the pancreatic islets. They further suggest that specific immune cells rather than humoral anti-islet antibodies are more likely to play the major role in this autoimmune animal model of diabetes.

Modelling the hypothalamic control of growth hormone secretion.

Here, we construct a mathematical model of the hypothalamic systems that control the secretion of growth hormone (GH). The work extends a recent model of the pituitary GH system, adding representations of the hypothalamic GH-releasing hormone (GHRH) and somatostatin neurones, each modelled as a single synchronised unit. An unpatterned stochastic input drives the GHRH neurones generating pulses of GHRH release that trigger GH pulses. Delayed feedback from GH results in increased somatostatin release, which inhibits both GH secretion and GHRH release, producing an overall pattern of 3-h pulses of GH secretion that is very similar to the secretory profile observed in male rats. Rather than directly stimulating somatostatin release, GH feedback triggers a priming effect, increasing releasable stores of somatostatin. Varying this priming effect to reduce the effect of GH can reproduce the less pulsatile form of GH release observed in the female rat. The model behaviour is tested by comparison with experimental observations with a range of different experimental protocols involving GHRH injections and somatostatin and GH infusion.

CT or not CT--that is the question. Whether 'tis better to evaluate clinically and x ray than to undertake a CT head scan!

OBJECTIVE: To evaluate the usage of computed tomography (CT) head scanning in children at the Royal Aberdeen Children's Hospital after the publication of the National Institute of Clinical Excellence (NICE) guidelines on the management of head injury. METHODS: The Accident and Emergency case records of all children presenting with a head injury over a three month period were reviewed and the number of attendances, radiographs, and CT head scans undertaken were noted. Also noted was the number of additional CT head scans that would have been performed if the NICE guidelines had been rigidly followed. RESULTS: Five hundred and thirty seven children were included in the study: 67% were boys. Two hundred and ten (39%) had skull radiographs: six demonstrated skull fractures and eight (1.5%) underwent CT head scan, with one positive report of a skull fracture. There were no reports of intracranial abnormalities. Ninety nine (18.4%) were admitted. Strictly applying all the NICE criteria for CT scanning would have resulted in an additional 54 patients being scanned. CONCLUSION: Rigid adherence to the NICE guidelines in all children with head injuries would have resulted in an almost eightfold increase in CT head scans performed. None of these children had clinical signs of intracranial injury and would have been exposed to a large amount of ionising radiation. The use of guidelines in practice must always be considered in conjunction with clinical judgement.

Chickenpox and stroke in childhood: a study of frequency and causation.

BACKGROUND AND PURPOSE: The purpose of this study was to determine whether infection with varicella is causal for arterial ischemic stroke (AIS) in children. METHODS: First, a prospective cohort study was conducted in young children (aged 6 months to 10 years) with AIS at 2 institutions (cohort study). The presence of varicella infection <12 months before AIS was determined and compared with the published frequency of varicella infection in the healthy pediatric population. The clinical and radiographic features of AIS were compared between the varicella and nonvaricella study cohorts. Second, a literature search of varicella-associated AIS was conducted, and the clinical and radiographic features were compared with the study nonvaricella cohort. RESULTS: In the cohort study, 22 (31%) of 70 consecutive children with AIS had a varicella infection in the preceding year compared with 9% in the healthy population. Children in the varicella cohort were more likely to have basal ganglia infarcts (P<0.001), abnormal cerebral vascular imaging (P<0.05), and recurrent AIS or transient ischemic attacks (P<0.05) than those in the nonvaricella cohort. The pooled literature analysis of 51 cases of varicella-associated AIS showed similar findings to the varicella cohort. CONCLUSION: In young children with AIS, there is a 3-fold increase in preceding varicella infection compared with published population rates, and varicella-associated AIS accounts for nearly one third of childhood AIS. Varicella-associated AIS has characteristic features, including a 2-fold increase in recurrent AIS and transient ischemic attacks. Varicella is an important risk factor for childhood AIS.