Mechanisms of COVID-19-associated olfactory dysfunction

Olfactory dysfunction is one of the most common symptoms of COVID-19. In the first 2 years of the pandemic, it was frequently reported, although its incidence has significantly decreased with the emergence of the Omicron variant, which has since become the dominant viral strain. Nevertheless, many patients continue to suffer from persistent dysosmia and dysgeusia, making COVID-19-associated olfactory dysfunction an ongoing health concern. The proposed pathogenic mechanisms of COVID-19-associated olfactory dysfunction are complex and likely multifactorial. While evidence suggests that infection of sustentacular cells and associated mucosal inflammation may be the culprit of acute, transient smell loss, alterations in other components of the olfactory system (e.g., olfactory receptor neuron dysfunction, olfactory bulb injury and alterations in the olfactory cortex) may lead to persistent, long-term olfactory dysfunction. This review aims to provide a comprehensive summary of the epidemiology, clinical manifestations and current understanding of the pathogenic mechanisms of COVID-19-associated olfactory dysfunction.

Skin keratinocyte-derived SIRT1 and BDNF modulate mechanical allodynia in mouse models of diabetic neuropathy

Diabetic neuropathy is a debilitating disorder characterized by spontaneous and mechanical allodynia. The role of skin mechanoreceptors in the development of mechanical allodynia is unclear. We discovered that mice with diabetic neuropathy had decreased sirtuin 1 (SIRT1) deacetylase activity in foot skin, leading to reduced expression of brain-derived neurotrophic factor (BDNF) and subsequent loss of innervation in Meissner corpuscles, a mechanoreceptor expressing the BDNF receptor TrkB. When SIRT1 was depleted from skin, the mechanical allodynia worsened in diabetic neuropathy mice, likely due to retrograde degeneration of the Meissner-corpuscle innervating Aβ axons and aberrant formation of Meissner corpuscles which may have increased the mechanosensitivity. The same phenomenon was also noted in skin-keratinocyte specific BDNF knockout mice. Furthermore, overexpression of SIRT1 in skin induced Meissner corpuscle reinnervation and regeneration, resulting in significant improvement of diabetic mechanical allodynia. Overall, the findings suggested that skin-derived SIRT1 and BDNF function in the same pathway in skin sensory apparatus regeneration and highlighted the potential of developing topical SIRT1-activating compounds as a novel treatment for diabetic mechanical allodynia.

Skin keratinocyte-derived SIRT1 and BDNF modulate mechanical allodynia in mouse models of diabetic neuropathy

Diabetic neuropathy is a debilitating disorder characterized by spontaneous and mechanical pain. The role of skin mechanoreceptors in the development of mechanical pain (allodynia) is unclear. We discovered that mice with diabetic neuropathy had decreased sirtuin 1 (SIRT1) deacetylase activity in foot skin, leading to reduced expression of brain-derived neurotrophic factor (BDNF) and subsequent loss of innervation in Meissner corpuscles, a mechanoreceptor expressing the BDNF receptor TrkB. When SIRT1 was depleted from skin, the mechanical allodynia worsened in diabetic neuropathy mice, likely due to retrograde degeneration of the Meissner-corpuscle innervating Aβ axons and aberrant formation of Meissner corpuscles which may have increased the mechanosensitivity. The same phenomenon was also noted in skin BDNF knockout mice. Furthermore, overexpression of SIRT1 in skin induced Meissner corpuscle reinnervation and regeneration, resulting in significant improvement of diabetic mechanical allodynia. Overall, the findings suggested that skin-derived SIRT1 and BDNF function in the same pathway in skin sensory apparatus regeneration and highlighted the potential of developing topical SIRT1-activating compounds as a novel treatment for diabetic mechanical allodynia.

Bayesian Forecasting of Bounded Poisson Distributed Time Series

This research models and forecasts bounded ordinal time series data that can appear in various contexts, such as air quality index (AQI) levels, economic situations, and credit ratings. This class of time series data is characterized by being bounded and exhibiting a concentration of large probabilities on a few categories, such as states 0 and 1. We propose using Bayesian methods for modeling and forecasting in zero-one-inflated bounded Poisson autoregressive (ZOBPAR) models, which are specifically designed to capture the dynamic changes in such ordinal time series data. We innovatively extend models to incorporate exogenous variables, marking a new direction in Bayesian inferences and forecasting. Simulation studies demonstrate that the proposed methods accurately estimate all unknown parameters, and the posterior means of parameter estimates are robustly close to the actual values as the sample size increases. In the empirical study we investigate three datasets of daily AQI levels from three stations in Taiwan and consider five competing models for the real examples. The results exhibit that the proposed method reasonably predicts the AQI levels in the testing period, especially for the Miaoli station.

CSF cytology of common primary CNS neoplasms categorized by CNS WHO 2021

OBJECTIVE

The detection of neoplastic cells in cerebral spinal fluid (CSF) is pivotal for the management of patients with central nervous system (CNS) tumours. This article delves into the CSF cytological characteristics of common CNS neoplasms, aligning with the 2021 World Health Organization (WHO) classification of CNS tumours.

METHODS

A retrospective review of CSF specimens positive for primary CNS neoplasms was performed at three tertiary medical centres. Only cases that had histopathologic confirmation and/or molecular workup were included.

RESULTS

Common primary CNS neoplasms seen in CSF cytology specimens include medulloblastoma, (non-WNT/non-SHH as well as SHH-activated and TP53 mutant), pineoblastoma, atypical teratoid/rhabdoid tumour (AT/RT), IDH-wildtype glioblastoma, and primary diffuse large B-cell lymphoma of the CNS. Ependymomas and germinomas can also have CSF involvement but are less common. Although the typical histologic architecture of these tumours may not be preserved in the CSF, unique cytomorphologic features such as nuclear moulding, nuclear pleomorphism, rhabdoid cells, prominent nucleoli and rosette formation can still be appreciated.

CONCLUSION

Adopting the updated terminology and correlating cytologic observations with molecular findings will streamline the diagnostic process, reducing the complexities and ambiguities pathologists often encounter when analysing CSF specimens for potential primary CNS neoplasms.

Sex disaggregated analysis of risk factors for adverse outcomes in hypertrophic cardiomyopathy

Background

Patient sex has been associated with differences in disease penetrance and clinical expression in HCM. We sought to investigate sex-disaggregated differences in risk factors for adverse outcomes in a large international HCM registry.

Methods

This is a retrospective study of HCM patients from the Sarcomeric Human Cardiomyopathy Registry. Cox proportional hazards models were fit with a sex interaction term to determine significant differences between sexes.

Results

6647 (38% women) probands with HCM were included. After a mean follow-up of 6.4 years from first encounter, women had a higher risk of heart failure (HF) composite (HR 1.77; 95% CI 1.56–1.99, p<0.0001), and death (1.22; 1.03–1.45, p=0.02) compared to men. No sex difference existed for ventricular arrhythmia composite (p=0.2) or atrial fibrillation (p=0.6). Sarcomere positive status (Sarc+) and causative variants in MYBPC3 reduced the risk of the HF composite for women, while for men there was no change in risk (P-heterogeneity=0.016 and <0.0001, respectively). Baseline LVEF <35% and larger LA size increased the risk of the HF composite for both sexes but to a greater magnitude in men (P-heterogeneity=0.0003 and 0.04 respectively) (Figure 1). Sarc+ increased the risk of death in men but not women (P-heterogeneity=0.041). Having the HF composite increased the risk of death by 45% in and 240% in men (P-heterogeneity=0.003) (Figure 2).

Conclusion

There are important sex differences in the risk of heart failure and death in those with HCM, with significant heterogeneity of outcomes based on subgroups defined by genetic and imaging factors.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): The Sarcomeric Human Cardiomyopathy Registry (SHaRe) is supported by an unrestricted research grant from Bristol Myer Squibb, including funds to individual sites for database support.

Postmortem Assessment of Olfactory Tissue Degeneration and Microvasculopathy in Patients With COVID-19

Importance

Loss of smell is an early and common presentation of COVID-19 infection. Although it has been speculated that viral infection of olfactory neurons may be the culprit, it is unclear whether viral infection causes injuries in the olfactory bulb region.

Objective

To characterize the olfactory pathology associated with COVID-19 infection in a postmortem study.

Design, Setting, and Participants

This multicenter postmortem cohort study was conducted from April 7, 2020, to September 11, 2021. Deceased patients with COVID-19 and control individuals were included in the cohort. One infant with congenital anomalies was excluded. Olfactory bulb and tract tissue was collected from deceased patients with COVID-19 and appropriate controls. Histopathology, electron microscopy, droplet digital polymerase chain reaction, and immunofluorescence/immunohistochemistry studies were performed. Data analysis was conducted from February 7 to October 19, 2021.

Main Outcomes and Measures

(1) Severity of degeneration, (2) losses of olfactory axons, and (3) severity of microvasculopathy in olfactory tissue.

Results

Olfactory tissue from 23 deceased patients with COVID-19 (median [IQR] age, 62 [49-69] years; 14 men [60.9%]) and 14 control individuals (median [IQR] age, 53.5 [33.25-65] years; 7 men [50%]) was included in the analysis. The mean (SD) axon pathology score (range, 1-3) was 1.921 (0.569) in patients with COVID-19 and 1.198 (0.208) in controls (P < .001), whereas axon density was 2.973 (0.963) × 104/mm2 in patients with COVID-19 and 3.867 (0.670) × 104/mm2 in controls (P = .002). Concomitant endothelial injury of the microvasculature was also noted in olfactory tissue. The mean (SD) microvasculopathy score (range, 1-3) was 1.907 (0.490) in patients with COVID-19 and 1.405 (0.233) in control individuals (P < .001). Both the axon and microvascular pathology was worse in patients with COVID-19 with smell alterations than those with intact smell (mean [SD] axon pathology score, 2.260 [0.457] vs 1.63 [0.426]; P = .002; mean [SD] microvasculopathy score, 2.154 [0.528] vs 1.694 [0.329]; P = .02) but was not associated with clinical severity, timing of infection, or presence of virus.

Conclusions and Relevance

This study found that COVID-19 infection is associated with axon injuries and microvasculopathy in olfactory tissue. The striking axonal pathology in some cases indicates that olfactory dysfunction in COVID-19 infection may be severe and permanent.

Radiomics Can Distinguish Pediatric Supratentorial Embryonal Tumors, High-Grade Gliomas, and Ependymomas

BACKGROUND AND PURPOSE

Pediatric supratentorial tumors such as embryonal tumors, high-grade gliomas, and ependymomas are difficult to distinguish by histopathology and imaging because of overlapping features. We applied machine learning to uncover MR imaging-based radiomics phenotypes that can differentiate these tumor types.

MATERIALS AND METHODS

Our retrospective cohort of 231 patients from 7 participating institutions had 50 embryonal tumors, 127 high-grade gliomas, and 54 ependymomas. For each tumor volume, we extracted 900 Image Biomarker Standardization Initiative-based PyRadiomics features from T2-weighted and gadolinium-enhanced T1-weighted images. A reduced feature set was obtained by sparse regression analysis and was used as input for 6 candidate classifier models. Training and test sets were randomly allocated from the total cohort in a 75:25 ratio.

RESULTS

The final classifier model for embryonal tumor-versus-high-grade gliomas identified 23 features with an area under the curve of 0.98; the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 0.85, 0.91, 0.79, 0.94, and 0.89, respectively. The classifier for embryonal tumor-versus-ependymomas identified 4 features with an area under the curve of 0.82; the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 0.93, 0.69, 0.76, 0.90, and 0.81, respectively. The classifier for high-grade gliomas-versus-ependymomas identified 35 features with an area under the curve of 0.96; the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 0.82, 0.94, 0.82, 0.94, and 0.91, respectively.

CONCLUSIONS

In this multi-institutional study, we identified distinct radiomic phenotypes that distinguish pediatric supratentorial tumors, high-grade gliomas, and ependymomas with high accuracy. Incorporation of this technique in diagnostic algorithms can improve diagnosis, risk stratification, and treatment planning.

Cytomorphologic Features Found in Cerebrospinal Fluid Specimens of Hemophagocytic Lymphohistiocytosis Patients

OBJECTIVES

Central nervous system involvement is present in 70% of patients with hemophagocytic lymphohistiocytosis (CNS-HLH). CNS-HLH is defined by neurologic deficits, neuroimaging abnormalities, or positive cerebrospinal fluid (CSF) findings. The CSF cytomorphologic spectrum of CNS-HLH, however, has not been well investigated.

METHODS

A retrospective review was performed on 64 CSF specimens from pediatric and adult patients with HLH. Ten patients had clinicoradiologic evidence of CNS involvement.

RESULTS

We identified five CSF cytomorphologic patterns: (1) hemophagocytosis, (2) vacuolated macrophages without evidence of hemophagocytosis, (3) monocytes and/or nonvacuolated macrophages, (4) acellular specimens, and (5) bloody specimens. Patterns 1 and 2 were common in CNS-HLH and rare in patients without CNS involvement. The CSF cytomorphologic patterns did not correlate well with WBC counts or protein concentration.

CONCLUSIONS

Our study offers a comprehensive view of the cytomorphologic features seen in CSF specimens from patients with HLH.

Radiomic Phenotypes Distinguish Atypical Teratoid/Rhabdoid Tumors from Medulloblastoma

BACKGROUND AND PURPOSE

Atypical teratoid/rhabdoid tumors and medulloblastomas have similar imaging and histologic features but distinctly different outcomes. We hypothesized that they could be distinguished by MR imaging-based radiomic phenotypes.

MATERIALS AND METHODS

We retrospectively assembled T2-weighted and gadolinium-enhanced T1-weighted images of 48 posterior fossa atypical teratoid/rhabdoid tumors and 96 match-paired medulloblastomas from 7 institutions. Using a holdout test set, we measured the performance of 6 candidate classifier models using 6 imaging features derived by sparse regression of 900 T2WI and 900 T1WI Imaging Biomarker Standardization Initiative-based radiomics features.

RESULTS

From the originally extracted 1800 total Imaging Biomarker Standardization Initiative-based features, sparse regression consistently reduced the feature set to 1 from T1WI and 5 from T2WI. Among classifier models, logistic regression performed with the highest AUC of 0.86, with sensitivity, specificity, accuracy, and F1 scores of 0.80, 0.82, 0.81, and 0.85, respectively. The top 3 important Imaging Biomarker Standardization Initiative features, by decreasing order of relative contribution, included voxel intensity at the 90th percentile, inverse difference moment normalized, and kurtosis-all from T2WI.

CONCLUSIONS

Six quantitative signatures of image intensity, texture, and morphology distinguish atypical teratoid/rhabdoid tumors from medulloblastomas with high prediction performance across different machine learning strategies. Use of this technique for preoperative diagnosis of atypical teratoid/rhabdoid tumors could significantly inform therapeutic strategies and patient care discussions.

Mindfulness-based interventions: an overall review

INTRODUCTION

This is an overall review on mindfulness-based interventions (MBIs).

SOURCES OF DATA

We identified studies in PubMed, EMBASE, CINAHL, PsycINFO, AMED, Web of Science and Google Scholar using keywords including 'mindfulness', 'meditation', and 'review', 'meta-analysis' or their variations.

AREAS OF AGREEMENT

MBIs are effective for improving many biopsychosocial conditions, including depression, anxiety, stress, insomnia, addiction, psychosis, pain, hypertension, weight control, cancer-related symptoms and prosocial behaviours. It is found to be beneficial in the healthcare settings, in schools and workplace but further research is warranted to look into its efficacy on different problems. MBIs are relatively safe, but ethical aspects should be considered. Mechanisms are suggested in both empirical and neurophysiological findings. Cost-effectiveness is found in treating some health conditions.

AREAS OF CONTROVERSY

Inconclusive or only preliminary evidence on the effects of MBIs on PTSD, ADHD, ASD, eating disorders, loneliness and physical symptoms of cardiovascular diseases, diabetes, and respiratory conditions. Furthermore, some beneficial effects are not confirmed in subgroup populations. Cost-effectiveness is yet to confirm for many health conditions and populations.

GROWING POINTS

Many mindfulness systematic reviews and meta-analyses indicate low quality of included studies, hence high-quality studies with adequate sample size and longer follow-up period are needed.

AREAS TIMELY FOR DEVELOPING RESEARCH

More research is needed on online mindfulness trainings and interventions to improve biopsychosocial health during the COVID-19 pandemic; Deeper understanding of the mechanisms of MBIs integrating both empirical and neurophysiological findings; Long-term compliance and effects of MBIs; and development of mindfulness plus (mindfulness+) or personalized mindfulness programs to elevate the effectiveness for different purposes.

Diagnosis of central nervous system invasive aspergillosis in a liver transplant recipient using microbial cell-free next generation DNA sequencing

Invasive aspergillosis (IA) is an important opportunistic infection among patients with liver disease and liver transplants. Diagnosis of IA may be challenging, especially among patients with central nervous system infection. Herein, we demonstrate the utility of next-generation sequencing of microbial cell-free DNA in the diagnosis of fungal brain abscess in a liver transplant recipient.

Brain Histopathology of Adult Decedents After Extracorporeal Membrane Oxygenation

OBJECTIVE

To test the hypothesis that brain injury is more common and varied in patients receiving extracorporeal membrane oxygenation (ECMO) than radiographically observed, we described neuropathology findings of ECMO decedents and associated clinical factors from 3 institutions.

METHODS

We conducted a retrospective multicenter observational study of brain autopsies from adult ECMO recipients. Pathology findings were examined for correlation with demographics, clinical data, ECMO characteristics, and outcomes.

RESULTS

Forty-three decedents (n = 13 female, median age 47 years) received autopsies after undergoing ECMO for acute respiratory distress syndrome (n = 14), cardiogenic shock (n = 14), and cardiac arrest (n = 15). Median duration of ECMO was 140 hours, most decedents (n = 40) received anticoagulants; 60% (n = 26) underwent venoarterial ECMO, and 40% (n = 17) underwent venovenous ECMO. Neuropathology was found in 35 decedents (81%), including microhemorrhages (37%), macrohemorrhages (35%), infarctions (47%), and hypoxic-ischemic brain injury (n = 17, 40%). Most pathology occurred in frontal neocortices (n = 43 occurrences), basal ganglia (n = 33), and cerebellum (n = 26). Decedents with hemorrhage were older (median age 57 vs 38 years, p = 0.01); those with hypoxic brain injury had higher Sequential Organ Failure Assessment scores (8.0 vs 2.0, p = 0.04); and those with infarction had lower peak Paco₂ (53 vs 61 mm Hg, p = 0.04). Six of 9 patients with normal neuroimaging results were found to have pathology on autopsy. The majority underwent withdrawal of life-sustaining therapy (n = 32, 74%), and 2 of 8 patients with normal brain autopsy underwent withdrawal of life-sustaining therapy for suspected neurologic injury.

CONCLUSION

Neuropathological findings after ECMO are common, varied, and associated with various clinical factors. Further study on underlying mechanisms is warranted and may guide ECMO management.

PATH-14. GENETIC SUSCEPTIBILITY AND OUTCOMES OF PEDIATRIC, ADOLESCENT AND YOUNG ADULT IDH-MUTANT ASTROCYTOMAS

INTRODUCTION

Previously thought to be rare, recent case series have shown that IDH mutations in young patients are more common than previously described. In this study, we analyzed IDH-mutant tumors to determine clinical significance of these mutations in children, adolescents and young adults.

METHODS

Through this multi-institution study (10 institutions), we collected 64 IDH1/2-mutant infiltrating astrocytoma specimens from 58 patients aged 4–26 (M:F, 0.4:0.6). Specimens included 46 low-grade (LGG) and 18 high-grade (HGG) astrocytomas. Tumor sequencing data (n=45), germline sequencing data (n=37) and outcome data (n=40) was analyzed.

RESULTS

Similar to adults, most sequenced tumors had a co-mutation in the TP53 gene, while ATRX mutations were less common and primarily seen in HGGs. Approximately 60% (n=21) of patients with germline data available had a mutation in a cancer predisposition gene. Mismatch repair (MMR) mutations were most common (n=12; MSH6 n=9), followed by TP53mutations (n=7). All patients with MMR gene mutations had HGGs and poor progression free (PFS=10% at 2 years, mean TTP=9 months) and overall (OS &lt;30% at 2 years) survival. Despite an OS of 90% at 5 years, many LGG patients had tumor progression/recurrence requiring additional treatment (PFS= 80% at 2 yrs, 40% at 5 yrs, mean TTP=3.5 years). Four LGG tumors (2 with TP53+ATRXloss, 2 with TP53 loss+1p19q co-deletion) underwent malignant transformation.

CONCLUSION

IDH-mutant tumors in pediatric patients are strongly associated with cancer predisposition and increased risk for progression/recurrence or malignant transformation. Routine screening for IDH1/2 mutations in children with grade 2–4 astrocytomas could greatly impact patient management.

Citrus flavonoids suppress IL-5 and ROS through distinct pathways in PMA/ionomycin-induced EL-4 cells

Interleukin-5 (IL-5) strongly initiates the asthmatic inflammatory response, which affects 300 million patients with asthma annually worldwide, through oxidative stress generation. Citrus flavonoids have beneficial properties, such as anti-inflammatory and antioxidant properties, but the precise molecular mechanism of the inhibition of the asthmatic inflammatory response is still unclear. This study aimed to investigate the underlying mechanisms of ROS and IL-5 reduction with citrus flavonoid treatment in PMA/ionomycin-induced EL-4 cells. Our results showed that hesperetin and gardenin A dramatically suppressed ROS and IL-5 production through distinct pathways. Interestingly, hesperidin induced HO-1 expression through the transcription factor Nrf2 coupled with the PI3K/AKT or ERK/JNK signaling pathway, consequently downregulating NFAT activity and IL-5 secretion. Likewise, gardenin A induced HO-1 expression and subsequently suppressed IL-5 production by reducing NFAT activity and upregulating PPARγ in EL-4 cells, suggesting that inducing HO-1 expression may inhibit asthmatic inflammation. Altogether, hesperidin and gardenin A have great potential for regulating the asthma-associated immune responses through antioxidant properties.

Deep Learning for Pediatric Posterior Fossa Tumor Detection and Classification: A Multi-Institutional Study

BACKGROUND AND PURPOSE

Posterior fossa tumors are the most common pediatric brain tumors. MR imaging is key to tumor detection, diagnosis, and therapy guidance. We sought to develop an MR imaging-based deep learning model for posterior fossa tumor detection and tumor pathology classification.

MATERIALS AND METHODS

The study cohort comprised 617 children (median age, 92 months; 56% males) from 5 pediatric institutions with posterior fossa tumors: diffuse midline glioma of the pons (n = 122), medulloblastoma (n = 272), pilocytic astrocytoma (n = 135), and ependymoma (n = 88). There were 199 controls. Tumor histology served as ground truth except for diffuse midline glioma of the pons, which was primarily diagnosed by MR imaging. A modified ResNeXt-50-32x4d architecture served as the backbone for a multitask classifier model, using T2-weighted MRIs as input to detect the presence of tumor and predict tumor class. Deep learning model performance was compared against that of 4 radiologists.

RESULTS

Model tumor detection accuracy exceeded an AUROC of 0.99 and was similar to that of 4 radiologists. Model tumor classification accuracy was 92% with an F₁ score of 0.80. The model was most accurate at predicting diffuse midline glioma of the pons, followed by pilocytic astrocytoma and medulloblastoma. Ependymoma prediction was the least accurate. Tumor type classification accuracy and F₁ score were higher than those of 2 of the 4 radiologists.

CONCLUSIONS

We present a multi-institutional deep learning model for pediatric posterior fossa tumor detection and classification with the potential to augment and improve the accuracy of radiologic diagnosis.

Murine models of IDH-wild-type glioblastoma exhibit spatial segregation of tumor initiation and manifestation during evolution

Recent characterization of spatiotemporal genomic architecture of IDH-wild-type multifocal glioblastomas (M-GBMs) suggests a clinically unobserved common-ancestor (CA) with a less aggressive phenotype, generating highly genetically divergent malignant gliomas/GBMs in distant brain regions. Using serial MRI/3D-reconstruction, whole-genome sequencing and spectral karyotyping-based single-cell phylogenetic tree building, we show two distinct types of tumor evolution in p53-mutant driven mouse models. Malignant gliomas/GBMs grow as a single mass (Type 1) and multifocal masses (Type 2), respectively, despite both exhibiting loss of Pten/chromosome 19 (chr19) and PI3K/Akt activation with sub-tetraploid/4N genomes. Analysis of early biopsied and multi-segment tumor tissues reveals no evidence of less proliferative diploid/2N lesions in Type 1 tumors. Strikingly, CA-derived relatively quiescent tumor precursors with ancestral diploid/2N genomes and normal Pten/chr19 are observed in the subventricular zone (SVZ), but are distantly segregated from multi focal Type 2 tumors. Importantly, PI3K/Akt inhibition by Rictor/mTORC2 deletion blocks distant dispersal, restricting glioma growth in the SVZ.

Clinicopathologic Features of Diencephalic Neuronal and Glioneuronal Tumors

Neuronal/mixed glioneuronal tumors are central nervous system neoplasms composed of neoplastic neuronal cell components or a mixture of glial and neuronal elements. They occur in cerebral hemispheres, posterior fossa, and spinal cord. Compared with other tumors at these locations, diencephalic neuronal/glioneuronal tumors are very rare and therefore not well characterized. We hereby performed clinicopathologic evaluation on 10 neuronal/glioneuronal tumors arising from the diencephalic region. Morphologically, these tumors resemble their histologic counterparts in other locations, except that lymphocytic infiltrates and microcalcifications are more common than Rosenthal fibers or eosinophilic granular bodies. The BRAFV600 mutation rate is 75%. Given the high percentage of samples being small biopsy specimens, the subtle histologic features and molecular findings greatly aided in establishing the pathologic diagnosis in several cases. At a median follow-up of 42 months, 71% of the tumors demonstrated radiological recurrence or progression, with median progression-free survival of 18 months. Recurrence/progression is observed in tumors across different histologic subtypes, necessitating additional therapies in 56% of the cases. Despite their bland histology, diencephalic neuronal/glioneuronal tumors are not clinically indolent. Their frequent recurrences warrant a close follow-up, and the prevalent BRAF mutation makes MAPK pathway inhibition a plausible treatment option when conventional therapies fail.

Harmonization of postmortem donations for pediatric brain tumors and molecular characterization of diffuse midline gliomas

Children diagnosed with brain tumors have the lowest overall survival of all pediatric cancers. Recent molecular studies have resulted in the discovery of recurrent driver mutations in many pediatric brain tumors. However, despite these molecular advances, the clinical outcomes of high grade tumors, including H3K27M diffuse midline glioma (H3K27M DMG), remain poor. To address the paucity of tissue for biological studies, we have established a comprehensive protocol for the coordination and processing of donated specimens at postmortem. Since 2010, 60 postmortem pediatric brain tumor donations from 26 institutions were coordinated and collected. Patient derived xenograft models and cell cultures were successfully created (76% and 44% of attempts respectively), irrespective of postmortem processing time. Histological analysis of mid-sagittal whole brain sections revealed evidence of treatment response, immune cell infiltration and the migratory path of infiltrating H3K27M DMG cells into other midline structures and cerebral lobes. Sequencing of primary and disseminated tumors confirmed the presence of oncogenic driver mutations and their obligate partners. Our findings highlight the importance of postmortem tissue donations as an invaluable resource to accelerate research, potentially leading to improved outcomes for children with aggressive brain tumors.

Somatic Mosaicism of IDH1 R132H Predisposes to Anaplastic Astrocytoma: A Case of Two Siblings

Anaplastic astrocytomas are aggressive glial cancers that present poor prognosis and high recurrence. Heterozygous IDH1 R132H mutations are common in adolescent and young adult anaplastic astrocytomas. In a majority of cases, the IDH1 R132H mutation is unique to the tumor, although rare cases of anaplastic astrocytoma have been described in patients with mosaic IDH1 mutations (Ollier disease or Maffucci syndrome). Here, we present two siblings with IDH1 R132H mutant high grade astrocytomas diagnosed at 14 and 26 years of age. Analysis of IDH^R132H mutations in the siblings' tumors and non-neoplastic tissues, including healthy regions of the brain, cheek cells, and primary teeth indicate mosaicism of IDH^R132H. Whole exome sequencing of the tumor tissue did not reveal any other common mutations between the two siblings. This study demonstrates the first example of IDH1 R132H mosaicism, acquired during early development, that provides an alternative mechanism of cancer predisposition.

Overexpression of Sirtuin 1 protein in neurons prevents and reverses experimental diabetic neuropathy

In diabetic neuropathy, there is activation of axonal and sensory neuronal degeneration pathways leading to distal axonopathy. The nicotinamide-adenine dinucleotide (NAD+)-dependent deacetylase enzyme, Sirtuin 1 (SIRT1), can prevent activation of these pathways and promote axonal regeneration. In this study, we tested whether increased expression of SIRT1 protein in sensory neurons prevents and reverses experimental diabetic neuropathy induced by a high fat diet (HFD). We generated a transgenic mouse that is inducible and overexpresses SIRT1 protein in neurons (nSIRT1OE Tg). Higher levels of SIRT1 protein were localized to cortical and hippocampal neuronal nuclei in the brain and in nuclei and cytoplasm of small to medium sized neurons in dorsal root ganglia. Wild-type and nSIRT1OE Tg mice were fed with either control diet (6.2% fat) or a HFD (36% fat) for 2 months. HFD-fed wild-type mice developed neuropathy as determined by abnormal motor and sensory nerve conduction velocity, mechanical allodynia, and loss of intraepidermal nerve fibres. In contrast, nSIRT1OE prevented a HFD-induced neuropathy despite the animals remaining hyperglycaemic. To test if nSIRT1OE would reverse HFD-induced neuropathy, nSIRT1OE was activated after mice developed peripheral neuropathy on a HFD. Two months after nSIRT1OE, we observed reversal of neuropathy and an increase in intraepidermal nerve fibre. Cultured adult dorsal root ganglion neurons from nSIRT1OE mice, maintained at high (30 mM) total glucose, showed higher basal and maximal respiratory capacity when compared to adult dorsal root ganglion neurons from wild-type mice. In dorsal root ganglion protein extracts from nSIRT1OE mice, the NAD+-consuming enzyme PARP1 was deactivated and the major deacetylated protein was identified to be an E3 protein ligase, NEDD4-1, a protein required for axonal growth, regeneration and proteostasis in neurodegenerative diseases. Our results indicate that nSIRT1OE prevents and reverses neuropathy. Increased mitochondrial respiratory capacity and NEDD4 activation was associated with increased axonal growth driven by neuronal overexpression of SIRT1. Therapies that regulate NAD+ and thereby target sirtuins may be beneficial in human diabetic sensory polyneuropathy.

Insertion loss of asymmetrical balconies on a building façade

The acoustical insertion loss of asymmetrical balconies on high-rise buildings was studied experimentally using a 1:3 scaled down model in the present study. Four balcony forms featured by the presence of a full-height side-wall were included. A linear loudspeaker array was adopted as the sound source. The effects of source orientation and balcony elevation angle on the insertion loss and its spectral variation were examined. The position of the full-height side-wall relative to the sound source significantly affects the balcony insertion loss. It is observed that the maximum traffic noise amplification and attenuation are both ∼6 dBA. Results also suggest that the balustrade has no effect on the insertion loss spectral variation pattern, though the insertion loss magnitude could be much reduced without it in the presence of a short side-wall. This short side-wall determines the insertion loss spectral variation pattern. Significant sound amplification is found at frequencies of the odd order transverse modes, the longitudinal modes, and their coupled modes regardless of balcony form and elevation angle. It is also found that the major acoustic mode interactions are basically independent of source orientation for balconies without the short side-wall.

Perineal and Radicular Pain Caused by Contralateral Sacral Nerve Root Schwannoma: Case Report and Review of Literature

BACKGROUND

Sacral schwannomas are very rare nerve sheath tumors. Patients usually present with a variety of nonspecific symptoms, which often lead to a delay in diagnosis. Although most schwannomas are benign, they present surgical challenges owing to their proximity to neurologic and other anatomic structures.

CASE DESCRIPTION

This 58-year-old female presented with a 2-month old history of left-sided perineal and radicular pain secondary to a right S2 sacral nerve root schwannoma. The sacral mass demonstrated homogenous enhancement with cystic changes in a T2-weighted magnetic resonance imaging sequence. The patient underwent S1-S3 laminectomy and tumor excision through a posterior surgical approach. Intraoperative monitoring was used to distinguish nonfunctional tissue during tumor resection. The patient had an unremarkable postoperative course.

CONCLUSIONS

Sacral schwannomas can present with a variety of nonspecific symptoms. They pose unique challenges given their location, size, and involvement of surrounding structures. Complete surgical resection is the main goal of sacral schwannoma treatment. A combined anterior-posterior surgical approach and a multidisciplinary surgical team are associated with improved outcomes.

Role of mitochondria in diabetic peripheral neuropathy: Influencing the NAD+-dependent SIRT1-PGC-1α-TFAM pathway

Survival of human peripheral nervous system neurons and associated distal axons is highly dependent on energy. Diabetes invokes a maladaptation in glucose and lipid energy metabolism in adult sensory neurons, axons and Schwann cells. Mitochondrial (Mt) dysfunction has been implicated as an etiological factor in failure of energy homeostasis that results in a low intrinsic aerobic capacity within the neuron. Over time, this energy failure can lead to neuronal and axonal degeneration and results in increased oxidative injury in the neuron and axon. One of the key pathways that is impaired in diabetic peripheral neuropathy (DPN) is the energy sensing pathway comprising the nicotinamide-adenine dinucleotide (NAD⁺)-dependent Sirtuin 1 (SIRT1)/peroxisome proliferator-activated receptor-γ coactivator α (PGC-1α)/Mt transcription factor A (TFAM or mtTFA) signaling pathway. Knockout of PGC-1α exacerbates DPN, whereas overexpression of human TFAM is protective. LY379268, a selective metabolomic glutamate receptor 2/3 (mGluR2/3) receptor agonist, also upregulates the SIRT1/PGC-1α/TFAM signaling pathway and prevents DPN through glutamate recycling in Schwann/satellite glial (SG) cells and by improving dorsal root ganglion (DRG) neuronal Mt function. Furthermore, administration of nicotinamide riboside (NR), a precursor of NAD⁺, prevents and reverses DPN, in part by increasing NAD⁺ levels and SIRT1 activity. In summary, we review the role of NAD⁺, mitochondria and the SIRT1-PGC-1α-TFAM pathway both from the perspective of pathogenesis and therapy in DPN.

Dynamics of the Phanerochaete carnosa transcriptome during growth on aspen and spruce

BACKGROUND

The basidiomycete Phanerochaete carnosa is a white-rot species that has been mainly isolated from coniferous softwood. Given the particular recalcitrance of softwoods to bioconversion, we conducted a comparative transcriptomic analysis of P. carnosa following growth on wood powder from one softwood (spruce; Picea glauca) and one hardwood (aspen; Populus tremuloides). P. carnosa was grown on each substrate for over one month, and mycelia were harvested at five time points for total RNA sequencing. Residual wood powder was also analyzed for total sugar and lignin composition.

RESULTS

Following a slightly longer lag phase of growth on spruce, radial expansion of the P. carnosa colony was similar on spruce and aspen. Consistent with this observation, the pattern of gene expression by P. carnosa on each substrate converged following the initial adaptation. On both substrates, highest transcript abundances were attributed to genes predicted to encode manganese peroxidases (MnP), along with auxiliary activities from carbohydrate-active enzyme (CAZy) families AA3 and AA5. In addition, a lytic polysaccharide monooxygenase from family AA9 was steadily expressed throughout growth on both substrates. P450 sequences from clans CPY52 and CYP64 accounted for 50% or more of the most highly expressed P450s, which were also the P450 clans that were expanded in the P. carnosa genome relative to other white-rot fungi.

CONCLUSIONS

The inclusion of five growth points and two wood substrates was important to revealing differences in the expression profiles of specific sequences within large glycoside hydrolase families (e.g., GH5 and GH16), and permitted co-expression analyses that identified new targets for study, including non-catalytic proteins and proteins with unknown function.

Nanoscale Removal of Picosecond Laser Ablation for Polymer

This paper analytically investigates the picosecond laser ablation of polymer. Laser-pulsed ablation is a well-established tool for polymer. However the ablation mechanism of laser processing for polymer has not been thoroughly understood yet. This study utilized a thermal transport model to analyze the relationship between the ablation rate and laser fluences. This model considered the energy balance at the decomposition interface as the ablation mechanisms and is applied to predict the laser-ablated depth of Acrylonitrile Butadiene Styrene/PolyVinyl Chloride (ABS/PVC). The calculated variation of the ablation rate with the logarithm of the laser fluence agrees with the measured data. The effects of material properties and processing parameters on the ablation depth per pulse are discussed for picosecond laser processing of ABS/PVC.

Endocrine mucin-producing sweat gland carcinoma: A study of 11 cases with molecular analysis

BACKGROUND

Endocrine mucin-producing sweat gland carcinoma (EMPSGC) is a rare, low-grade adnexal neoplasm that most commonly involves the eyelid. Analogous to solid papillary carcinoma of the breast, it probably represents a precursor lesion to mucinous carcinoma. Here, we describe 11 cases of EMPSGC with molecular analysis.

METHODS

We performed a retrospective search of the Johns Hopkins Medical Institute pathology database and identified 11 cases of EMPSGC. Immunohistochemistry was performed for chromogranin, synaptophysin, neuron specific enolase, estrogen receptor (ER), epithelial membrane antigen (EMA), cytokeratin 7 (CK7), and cytokeratin 20 (CK20). Array comparative genomic hybridization (aCGH) and BRAFV600E pyrosequencing were performed on two and three cases, respectively.

RESULTS

We observed a strong female predilection (73% females, 8/11 cases) with an average age of 66 years (range, 56-83 years). EMPSGCs were associated with adjacent benign sweat gland cysts (3/11), atypical intraductal proliferation (1/11), and mucinous carcinoma (1/11). Immunohistochemically, all tumors expressed at least one neuroendocrine marker, ER, EMA, and CK7, and were negative for CK20. aCGH demonstrated a 6p11.2 to 6q16.1 deletion (1/2 cases). All cases were negative for BRAFV600E mutation (3/3 cases).

CONCLUSION

This series provides further histopathologic support that EMPSGC represents a multistage progression to mucinous carcinoma. Additional studies are needed to understand its molecular mechanisms.

Cross-species transcriptional analysis reveals conserved and host-specific neoplastic processes in mammalian glioma

Glioma is a unique neoplastic disease that develops exclusively in the central nervous system (CNS) and rarely metastasizes to other tissues. This feature strongly implicates the tumor-host CNS microenvironment in gliomagenesis and tumor progression. We investigated the differences and similarities in glioma biology as conveyed by transcriptomic patterns across four mammalian hosts: rats, mice, dogs, and humans. Given the inherent intra-tumoral molecular heterogeneity of human glioma, we focused this study on tumors with upregulation of the platelet-derived growth factor signaling axis, a common and early alteration in human gliomagenesis. The results reveal core neoplastic alterations in mammalian glioma, as well as unique contributions of the tumor host to neoplastic processes. Notable differences were observed in gene expression patterns as well as related biological pathways and cell populations known to mediate key elements of glioma biology, including angiogenesis, immune evasion, and brain invasion. These data provide new insights regarding mammalian models of human glioma, and how these insights and models relate to our current understanding of the human disease.

mGluR2/3 activation of the SIRT1 axis preserves mitochondrial function in diabetic neuropathy

Objectives

There is a critical need to develop effective treatments for diabetic neuropathy. This study determined if a selective mGluR2/3 receptor agonist prevented or treated experimental diabetic peripheral neuropathy (DPN) through glutamate recycling and improved mitochondrial function.

Methods

Adult male streptozotocin treated Sprague-Dawley rats with features of type 1 diabetes mellitus (T1DM) or Low Capacity Running (LCR) rats with insulin resistance or glucose intolerance were treated with 3 or 10 mg/kg/day LY379268. Neuropathy end points included mechanical allodynia, nerve conduction velocities (NCV), and intraepidermal nerve fiber density (IENFD). Markers of oxidative stress, antioxidant response, glutamate recycling pathways, and mitochondrial oxidative phosphorylation (OXPHOS) associated proteins were measured in dorsal root ganglia (DRG).

Results

In diabetic rats, NCV and IENFD were decreased. Diabetic rats treated with an mGluR2/3 agonist did not develop neuropathy despite remaining diabetic. Diabetic DRG showed increased levels of oxidized proteins, decreased levels of glutathione, decreased levels of mitochondrial DNA (mtDNA) and OXPHOS proteins. In addition, there was a 20-fold increase in levels of glial fibrillary acidic protein (GFAP) and the levels of glutamine synthetase and glutamate transporter proteins were decreased. When treated with a specific mGluR2/3 agonist, levels of glutathione, GFAP and oxidized proteins were normalized and levels of superoxide dismutase 2 (SOD2), SIRT1, PGC-1α, TFAM, glutamate transporter proteins, and glutamine synthetase were increased in DRG neurons.

Interpretation

Activation of glutamate recycling pathways protects diabetic DRG and this is associated with activation of the SIRT1-PGC-1α-TFAM axis and preservation of mitochondrial OXPHOS function.

Differential Neuronal Susceptibility and Apoptosis in Congenital Zika Virus Infection

Background

Zika virus (ZIKV) infection during pregnancy may result in severe neurologic injury to the fetus. The mechanisms by which ZIKV injures fetal brain are not fully characterized. Although cell culture and animal models shed valuable insight into pathogenesis, they do not fully recapitulate human disease.

Methods

To characterize the mechanism of ZIKV-induced human brain injury, we performed immunolabeling on brain tissue from a 20-week fetus with intrauterine ZIKV infection. Formalin-fixed sections of brain tissue were co-immunostained with ZIKV envelope antibody, as well as neuronal and non-neuronal lineage cell markers to assess infection within populations. Apoptosis was assessed by quantifying activated caspase 3 -positive staining cells. Minimum 3–5 random microscopic fields per brain region were photographed and quantified in an automated fashion using the ImageJ Cell Counter plug-in. GraphPad Prism and Microsoft Excel software were used for data analysis.

Results

ZIKV demonstrated a wide range of neuronal and non-neuronal tropism. However, infection rate was highest in Tbr2+ - Intermediate Progenitor Cells (IPC; 81.4±12%) and DCX+ Immature Neurons (IN; 51.5±13.9%), followed by SOX2+/ Nestin+ Neural Precursor Cells (NPC; 26.6±13.4%). NeuN+ Mature Neurons had the lowest frequency of infection (MN; 10.0±7.0 %) (Figure). Apoptosis was observed in both infected and uninfected bystander cortical neurons. A high infection frequency was also observed in non-neuronal cells (astrocytes, microglia, macrophages, lymphocytes).

Conclusion

Our study provides valuable insights into ZIKV pathogenesis in the fetus; it is the first to demonstrate differential infectivity/susceptibility of neuronal lineage cells to ZIKV, and evidence of apoptosis in and around these cells. The high frequency of ZIKV+ IPC and IN implies that that infection can be supported until the immature stage of neuronal differentiation. The resistance of mature neurons to ZIKV infection may also explain why ZIKV infection in the third trimester poses less risk of microcephaly in infants. The high infection rate of non-neuronal cells also suggests potential contribution of immune-mediated mechanisms of brain injury in the setting of congenital ZIKV infection.

Disclosures

All authors: No reported disclosures.

Differential neuronal susceptibility and apoptosis in congenital Zika virus infection

To characterize the mechanism of Zika virus (ZIKV)-associated microcephaly, we performed immunolabeling on brain tissue from a 20-week fetus with intrauterine ZIKV infection. Although ZIKV demonstrated a wide range of neuronal and non-neuronal tropism, the infection rate was highest in intermediate progenitor cells and immature neurons. Apoptosis was observed in both infected and uninfected bystander cortical neurons, suggesting a role for paracrine factors in induction of neuronal apoptosis. Our results highlight differential neuronal susceptibility and neuronal apoptosis as potential mechanisms in the development of ZIKV-associated microcephaly, and may provide insights into the design and best timing of future therapy. Ann Neurol 2017;82:121-127.

Therapeutic and Prognostic Implications of BRAF V600E in Pediatric Low-Grade Gliomas

Purpose BRAF V600E is a potentially highly targetable mutation detected in a subset of pediatric low-grade gliomas (PLGGs). Its biologic and clinical effect within this diverse group of tumors remains unknown. Patients and Methods A combined clinical and genetic institutional study of patients with PLGGs with long-term follow-up was performed (N = 510). Clinical and treatment data of patients with BRAF V600E mutated PLGG (n = 99) were compared with a large international independent cohort of patients with BRAF V600E mutated-PLGG (n = 180). Results BRAF V600E mutation was detected in 69 of 405 patients (17%) with PLGG across a broad spectrum of histologies and sites, including midline locations, which are not often routinely biopsied in clinical practice. Patients with BRAF V600E PLGG exhibited poor outcomes after chemotherapy and radiation therapies that resulted in a 10-year progression-free survival of 27% (95% CI, 12.1% to 41.9%) and 60.2% (95% CI, 53.3% to 67.1%) for BRAF V600E and wild-type PLGG, respectively ( P < .001). Additional multivariable clinical and molecular stratification revealed that the extent of resection and CDKN2A deletion contributed independently to poor outcome in BRAF V600E PLGG. A similar independent role for CDKN2A and resection on outcome were observed in the independent cohort. Quantitative imaging analysis revealed progressive disease and a lack of response to conventional chemotherapy in most patients with BRAF V600E PLGG. Conclusion BRAF V600E PLGG constitutes a distinct entity with poor prognosis when treated with current adjuvant therapy.

Aβ Amyloid Pathology Affects the Hearts of Patients With Alzheimer's Disease: Mind the Heart

BACKGROUND

Individually, heart failure (HF) and Alzheimer's disease (AD) are severe threats to population health, and their potential coexistence is an alarming prospect. In addition to sharing analogous epidemiological and genetic profiles, biochemical characteristics, and common triggers, the authors recently recognized common molecular and pathological features between the 2 conditions. Whereas cognitive impairment has been linked to HF through perfusion defects, angiopathy, and inflammation, whether patients with AD present with myocardial dysfunction, and if the 2 conditions bear a common pathogenesis as neglected siblings are unknown.

OBJECTIVES

Here, the authors investigated whether amyloid beta (Aβ) protein aggregates are present in the hearts of patients with a primary diagnosis of AD, affecting myocardial function.

METHODS

The authors examined myocardial function in a retrospective cross-sectional study from a cohort of AD patients and age-matched controls. Imaging and proteomics approaches were used to identify and quantify Aβ deposits in AD heart and brain specimens compared with controls. Cell shortening and calcium transients were measured on isolated adult cardiomyocytes.

RESULTS

Echocardiographic measurements of myocardial function suggest that patients with AD present with an anticipated diastolic dysfunction. As in the brain, Aβ₄₀ and Aβ₄₂ are present in the heart, and their expression is increased in AD.

CONCLUSIONS

Here, the authors provide the first report of the presence of compromised myocardial function and intramyocardial deposits of Aβ in AD patients. The findings depict a novel biological framework in which AD may be viewed either as a systemic disease or as a metastatic disorder leading to heart, and possibly multiorgan failure. AD and HF are both debilitating and life-threatening conditions, affecting enormous patient populations. Our findings underline a previously dismissed problem of a magnitude that will require new diagnostic approaches and treatments for brain and heart disease, and their combination.

Cavernous Nerve Injury by Radiation Therapy May Potentiate Erectile Dysfunction in Rats

PURPOSE/OBJECTIVES

Radiation-induced erectile-dysfunction (RiED) is one of the most common side effects of radiation therapy (RT) and significantly reduces the quality of life (QoL) of cancer patients. Approximately 50% of prostate cancer patients experience RiED within 3 to 5 years after completion of RT. A series of vascular, muscular, and neurogenic injuries after prostate RT lead to RiED; however, the precise role of RT-induced neurogenic injury in RiED has not been fully established. The cavernous nerves (CN) are postganglionic parasympathetic nerves located beside the prostate gland that assist in penile erection. This study was designed to investigate the role of CN injury, tissue damage, and altered signaling pathways in an RiED rat model.

METHODS AND MATERIALS

Male rats were exposed to a single dose of 25 Gy prostate-confined RT. Erectile function was evaluated by intracavernous pressure (ICP) measurements conducted both 9 and 14 weeks after RT. Neuronal injury was evaluated in the CN using quantitative polymerase chain reaction, conduction studies, transmission electron microscopy, and immunoblotting. Masson trichrome staining was performed to elucidate fibrosis level in penile tissues.

RESULTS

There were significant alterations in the ICP (P<.0001) of RT rats versus non-RT rats. TEM analysis showed decreased myelination, increased microvascular damage, and progressive axonal atrophy of the CN fibers after RT. Electrophysiologic analysis showed significant impairment of the CN conduction velocity after RT. RT also significantly increased RhoA/Rho-associated protein kinase 1 (ROCK1) mRNA and protein expression. In addition, penile tissue showed increased apoptosis and fibrosis 14 weeks after RT.

CONCLUSIONS

RT-induced CN injury may contribute to RiED; this is therefore a rationale for developing novel therapeutic strategies to mitigate CN and tissue damage. Moreover, further investigation of the RhoA/ROCK pathway's role in mitigating RiED is necessary.

Pediatric low-grade gliomas: implications of the biologic era

For the past decade, it has been recognized that pediatric low-grade gliomas (LGGs) and glial-neuronal tumors carry distinct molecular alterations with resultant aberrant intracellular signaling in the Ras-mitogen-activated protein kinase pathway. The conclusions and recommendations of a consensus conference of how best to integrate the growing body of molecular genetic information into tumor classifications and, more importantly, for future treatment of pediatric LGGs are summarized here. There is uniform agreement that molecular characterization must be incorporated into classification and is increasingly critical for appropriate management. Molecular-targeted therapies should be integrated expeditiously, but also carefully into the management of these tumors and success measured not only by radiographic responses or stability, but also by functional outcomes. These trials need to be carried out with the caveat that the long-term impact of molecularly targeted therapy on the developing nervous system, especially with long duration treatment, is essentially unknown.

Radiological diagnosis of drop metastases from paediatric brain tumours using combination of 2D and 3D MRI sequences

AIM

To evaluate spinal magnetic resonance imaging (MRI) examinations using a combination of two-dimensional (2D) and three-dimensional (3D) MRI sequences for diagnosis of drop metastases.

MATERIALS AND METHODS

Fifty-five paediatric patients with primary brain tumours were evaluated for drop metastases at initial presentation using spinal MRI including sagittal 2D T1-weighted (W) contrast-enhanced (+C), axial 3D T1W+C volumetric interpolated breath-hold (VIBE), and sagittal 3D T2W SPACE (Sampling Perfection with Application optimised Contrasts using different flip angle Evolutions).

RESULTS

The MRI false-negative rate was 4%, and cerebrospinal fluid (CSF) false-negative rate was 16% (p=0.07). The 3D T1W+C VIBE increased the number of drop metastases detected in 42% of patients. Drop metastases were more conspicuous in 25% of patients on 3D T2W SPACE.

CONCLUSION

Spinal MRI examinations including 2D and 3D sequences demonstrate characteristics that may improve radiological diagnosis of drop metastases.

Diagnostic Performance of Ultrafast Brain MRI for Evaluation of Abusive Head Trauma

BACKGROUND AND PURPOSE

MR imaging with sedation is commonly used to detect intracranial traumatic pathology in the pediatric population. Our purpose was to compare nonsedated ultrafast MR imaging, noncontrast head CT, and standard MR imaging for the detection of intracranial trauma in patients with potential abusive head trauma.

MATERIALS AND METHODS

A prospective study was performed in 24 pediatric patients who were evaluated for potential abusive head trauma. All patients received noncontrast head CT, ultrafast brain MR imaging without sedation, and standard MR imaging with general anesthesia or an immobilizer, sequentially. Two pediatric neuroradiologists independently reviewed each technique blinded to other modalities for intracranial trauma. We performed interreader agreement and consensus interpretation for standard MR imaging as the criterion standard. Diagnostic accuracy was calculated for ultrafast MR imaging, noncontrast head CT, and combined ultrafast MR imaging and noncontrast head CT.

RESULTS

Interreader agreement was moderate for ultrafast MR imaging (κ = 0.42), substantial for noncontrast head CT (κ = 0.63), and nearly perfect for standard MR imaging (κ = 0.86). Forty-two percent of patients had discrepancies between ultrafast MR imaging and standard MR imaging, which included detection of subarachnoid hemorrhage and subdural hemorrhage. Sensitivity, specificity, and positive and negative predictive values were obtained for any traumatic pathology for each examination: ultrafast MR imaging (50%, 100%, 100%, 31%), noncontrast head CT (25%, 100%, 100%, 21%), and a combination of ultrafast MR imaging and noncontrast head CT (60%, 100%, 100%, 33%). Ultrafast MR imaging was more sensitive than noncontrast head CT for the detection of intraparenchymal hemorrhage (P = .03), and the combination of ultrafast MR imaging and noncontrast head CT was more sensitive than noncontrast head CT alone for intracranial trauma (P = .02).

CONCLUSIONS

In abusive head trauma, ultrafast MR imaging, even combined with noncontrast head CT, demonstrated low sensitivity compared with standard MR imaging for intracranial traumatic pathology, which may limit its utility in this patient population.

Alexander Disease

Alexander disease is a leukodystrophy caused by dominant missense mutations in the gene encoding the glial fibrillary acidic protein. Individuals with this disorder often present with a typical neuroradiologic pattern including white matter abnormalities with brainstem involvement, selective contrast enhancement, and structural changes to the basal ganglia/thalamus. In rare cases, focal lesions have been seen and cause concern for primary malignancies. Here the authors present an infant initially diagnosed with a chiasmatic astrocytoma that was later identified as having glial fibrillary acidic protein mutation-confirmed Alexander disease. Pathologic and radiologic considerations that were helpful in arriving at the correct diagnosis are discussed.

Repeat surgery for focal cortical dysplasias in children: indications and outcomes

OBJECTIVE Focal cortical dysplasia (FCD) is a common cause of medically intractable epilepsy that often may be treated by surgery. Following resection, many patients continue to experience seizures, necessitating a decision for further surgery to achieve the desired seizure outcomes. Few studies exist on the efficacy of reoperation for intractable epilepsy due to FCD in pediatric cohorts, including the definition of prognostic factors correlated with clinical benefit from further resection. METHODS The authors retrospectively analyzed the medical records and MR images of 22 consecutive pediatric patients who underwent repeat FCD resection after unsuccessful first surgery at the Children's National Health System between March 2005 and April 2015. RESULTS Accounting for all reoperations, 13 (59%) of the 22 patients achieved complete seizure freedom and another 5 patients (23%) achieved significant improvement in seizure control. Univariate analysis demonstrated that concordance in electrocorticography (ECoG) and MRI localization (p = 0.005), and completeness of resection (p = 0.0001), were associated with seizure freedom after the first reoperation. Patients with discordant ECoG and MRI findings ultimately benefited from aggressive multilobe lobectomy or hemispherectomy. Repeat lesionectomies utilizing intraoperative MRI (iMRI; n = 9) achieved complete resection and seizure freedom in all cases. CONCLUSIONS Reoperation may be clinically beneficial in patients with intractable epilepsy due to FCD. Patients with concordant intraoperative ECoG and MRI localization may benefit from extended resection of residual dysplasia at the margins of the previous lesional cavity, and iMRI may offer benefits as a quality control mechanism to ensure that a complete resection has been accomplished. Patients with discordant findings may benefit from more aggressive resections at earlier stages to achieve better seizure control and ensure functional plasticity.

Zika Virus Infection with Prolonged Maternal Viremia and Fetal Brain Abnormalities

The current outbreak of Zika virus (ZIKV) infection has been associated with an apparent increased risk of congenital microcephaly. We describe a case of a pregnant woman and her fetus infected with ZIKV during the 11th gestational week. The fetal head circumference decreased from the 47th percentile to the 24th percentile between 16 and 20 weeks of gestation. ZIKV RNA was identified in maternal serum at 16 and 21 weeks of gestation. At 19 and 20 weeks of gestation, substantial brain abnormalities were detected on ultrasonography and magnetic resonance imaging (MRI) without the presence of microcephaly or intracranial calcifications. On postmortem analysis of the fetal brain, diffuse cerebral cortical thinning, high ZIKV RNA loads, and viral particles were detected, and ZIKV was subsequently isolated.

Resective surgery for focal cortical dysplasia in children: a comparative analysis of the utility of intraoperative magnetic resonance imaging (iMRI)

PURPOSE

Seizure freedom following resection of focal cortical dysplasia (FCD) correlates with complete resection of the dysplastic cortical tissue. However, difficulty with intraoperative identification of the lesion may limit the ability to achieve the surgical objective of complete extirpation of these lesions. Intraoperative magnetic resonance imaging (iMRI) may aid in FCD resections. The objective of this study is to compare rates of postoperative seizure freedom, completeness of resection, and need for reoperation in patients undergoing iMRI-assisted FCD resection versus conventional surgical techniques.

METHODS

We retrospectively reviewed the medical records of pediatric subjects who underwent surgical resection of FCD at Children's National Medical Center between March 2005 and April 2015.

RESULTS

At the time of the last postoperative follow-up, 11 of the 12 patients (92 %) in the iMRI resection group were seizure free (Engel Class I), compared to 14 of the 42 patients (33 %) in the control resection group (p = 0.0005). All 12 of the iMRI patients (100 %) achieved complete resection, compared to 24 of 42 patients (57 %) in the control group (p = 0.01). One (8 %) patient from the iMRI-assisted resection group has required reoperation, compared to 17 (40 %) patients in the control resection group.

CONCLUSION

Our results suggest that the utilization of iMRI during surgery for resection of FCD results in improved postoperative seizure freedom, completeness of lesion resection, and reduction in the need for reoperation.