Genetic Alteration Analysis of IDH1, IDH2, CDKN2A, MYB and MYBL1 in Pediatric Low-Grade Gliomas.

Objective: To investigate pediatric low-grade gliomas for alterations in IDH1, IDH2, CDKN2A, MYB, and MYBL1. Materials and Methods: DNA and RNA were extracted from 62 pediatric gliomas. Molecular methods included PCR, RT-PCR, and RNA sequencing; Sanger sequencing was used for validation. Results: Analysis for hotspot genetic alterations in IDH1 R132 and IDH2 R172 (45 and 33 samples) was negative in all cases. CDKN2A deletions were detected in exons 1 and 2 in 1 (pleomorphic xanthoastrocytoma) sample of 9 samples analyzed. Of 10 samples analyzed for MYB translocation, 4 each were positive for translocations with exon 2 and exon 3 of PCDHGA1. Six samples showed MYBL rearrangement. The lack of IDH1/2 genetic alterations is in accordance with the literature in pediatric tumors. Alterations in MYB, MYBL were recently reported to characterize diffuse grade II, but not grade I, gliomas. Conclusion: We optimized methods for analyzing gene variations and correlated the findings to pathological grade. The high incidence of MYB and MYBL need further evaluation. We also compared DNA, RNA, and RNA sequencing results for fusion, translocation, and genetic alterations. More accurate identification of the underlying biology of pediatric gliomas has implications for the development of targeted treatment.

Postoperative hydrocephalus management may cause delays in adjuvant treatment following paediatric posterior fossa tumour resection: a multicentre retrospective observational study.

INTRODUCTION: Hydrocephalus persists in 10-40% of children with posterior fossa tumours (PFT). A delay in commencement of adjuvant therapy (AT) can negatively influence survival. The objective of this study was to determine whether postoperative cerebrospinal fluid (CSF) diversion procedures caused potentially preventable delays in AT. METHODS: A retrospective study of children diagnosed with PFT requiring AT from 2004 to 2018 from two large centres was conducted. Data on histology, timing of ventriculo-peritoneal shunt (VPS) insertion, and AT was collected. The modified Canadian Preoperative Prediction Rule for Hydrocephalus (mCPPRH) score was calculated. The primary outcome was delay in AT beyond 40 days post-resection. Progression-free and overall survival were assessed. RESULTS: Out of 196 primary PFT resections, 144 fitted the inclusion criteria. Mean age was 6.57 ± 4.62. Histology was medulloblastoma (104), ependymoma (27), and others (13). Forty patients had a VPS inserted; 17 of these experienced a delay in AT. A total of 104 patients were not shunted; 15 of these had delayed AT (p = 0.0007). Patients who had a VPS insertion had longer intervals from surgery to commencement of AT (34.5 vs 30.8, p = 0.05). There was no significant difference in mCPPRH score between those who had a VPS (4.03) and those who did not (3.61; p = 0.252). Multivariable linear regression modelling did not show a significant effect of VPS or mCPPRH on progression-free survival or OS. CONCLUSION: CSF diversion procedures may cause a preventable delay in the initiation of adjuvant therapy. Early post-operative VP shunt insertion, rather than a 'wait and see policy' should be considered in order to reduce this delay.

Characterization of Diabetic Retinopathy in Two Mouse Models and Response to a Single Injection of Anti-Vascular Endothelial Growth Factor.

In this study, we characterized diabetic retinopathy in two mouse models and the response to anti-vascular endothelial growth factor (VEGF) injection. The study was conducted in 58 transgenic, non-obese diabetic (NOD) mice with spontaneous type 1 diabetes (n = 30, DMT1-NOD) or chemically induced (n = 28, streptozotocin, STZ-NOD) type 1 diabetes and 20 transgenic db/db mice with type 2 diabetes (DMT2-db/db); 30 NOD and 8 wild-type mice served as controls. Mice were examined at 21 days for vasculopathy, retinal thickness, and expression of genes involved in oxidative stress, angiogenesis, gliosis, and diabetes. The right eye was histologically examined one week after injection of bevacizumab, ranibizumab, saline, or no treatment. Flat mounts revealed microaneurysms and one apparent area of tufts of neovascularization in the diabetic retina. Immunostaining revealed activation of Müller glia and prominent Müller cells. Mean retinal thickness was greater in diabetic mice. RAGE increased and GFAP decreased in DMT1-NOD mice; GFAP and SOX-9 mildly increased in db/db mice. Anti-VEGF treatment led to reduced retinal thickness. Retinas showed vasculopathy and edema in DMT1-NOD and DMT2-db/db mice and activation of Müller glia in DMT1-NOD mice, with some response to anti-VEGF treatment. Given the similarity of diabetic retinopathy in mice and humans, comparisons of type 1 and type 2 diabetic mouse models may assist in the development of new treatment modalities.

Classifying Medulloblastoma Subgroups Based on Small, Clinically Achievable Gene Sets.

As treatment protocols for medulloblastoma (MB) are becoming subgroup-specific, means for reliably distinguishing between its subgroups are a timely need. Currently available methods include immunohistochemical stains, which are subjective and often inconclusive, and molecular techniques-e.g., NanoString, microarrays, or DNA methylation assays-which are time-consuming, expensive and not widely available. Quantitative PCR (qPCR) provides a good alternative for these methods, but the current NanoString panel which includes 22 genes is impractical for qPCR. Here, we applied machine-learning-based classifiers to extract reliable, concise gene sets for distinguishing between the four MB subgroups, and we compared the accuracy of these gene sets to that of the known NanoString 22-gene set. We validated our results using an independent microarray-based dataset of 92 samples of all four subgroups. In addition, we performed a qPCR validation on a cohort of 18 patients diagnosed with SHH, Group 3 and Group 4 MB. We found that the 22-gene set can be reduced to only six genes (IMPG2, NPR3, KHDRBS2, RBM24, WIF1, and EMX2) without compromising accuracy. The identified gene set is sufficiently small to make a qPCR-based MB subgroup classification easily accessible to clinicians, even in developing, poorly equipped countries.

Differences in RNA and microRNA Expression Between PTCH1- and SUFU-mutated Medulloblastoma.

BACKGROUND/AIM: Germline mutations in PTCH1 or SUFU in the sonic hedgehog (SHH) pathway cause Gorlin's syndrome with increased risk of developing SHH-subgroup medulloblastoma. Gorlin's syndrome precludes the use of radiotherapy (a standard component of treatment) due to the development of multiple basal cell carcinomas. Also, current SHH inhibitors are ineffective against SUFU-mutated medulloblastoma, as they inhibit upstream genes. In this study, we aimed to detect differences in the expression of genes and microRNAs between SUFU- and PTCH1-mutated SHH medulloblastomas which may hint at new treatment directions. PATIENTS AND METHODS: We sequenced RNA and microRNA from tumors of two patients with germline Gorlin's syndrome - one having PTCH1 mutation and one with SUFU mutation - followed by bioinformatics analysis to detect changes in genes and miRNAs expression in these two tumors. Expression changes were validated using qRT-PCR. Ingenuity pathway analysis was performed in search for targetable pathways. RESULTS: Compared to the PTCH1 tumor, the SUFU tumor demonstrated lower expression of miR-301a-3p and miR-181c-5p, matrix metallopeptidase 11 (MMP11) and OTX2, higher expression of miR-7-5p and corresponding lower expression of its targeted gene, connexin 30 (GJB6). We propose mechanisms to explain the phenotypic differences between the two types of tumors, and understand why PTCH1 and SUFU tumors tend to relapse locally (rather than metastatically as in other medulloblastoma subgroups). CONCLUSION: Our results help towards finding new treatable molecular targets for these types of medulloblastomas.

Proptosis due to intraorbital space-occupying lesions in children.

PURPOSE: To report the 10-year experience of two tertiary medical centers with children presenting with proptosis due to an intraorbital space-occupying lesion. METHODS: Patients were identified by file review. Data were collected on demographics, findings on ophthalmologic and imaging evaluations, etiology, treatment, and outcome. RESULTS: Nineteen children (7 male) were included. Eleven patients had optic nerve glioma, including 9 with substantially decreased visual acuity. Treatment consisted of chemotherapy alone or with radiation, resection or anti-VEGF agents, MEK inhibitor, or observation only (n = 1). Visual and cosmetic outcomes were poor in all cases. Outcome for arteriovenous malformations was good following corticosteroid treatment (n = 1), but catheterization led to persistent proptosis and fluctuating visual acuity (n = 1). Compound capillary hemangioma (n = 1) was treated with laser and systemic beta blockers with satisfactory results. Rhabdomyosarcoma had a good prognosis in one patient treated with resection and radiation but was fatal in another even after chemotherapy. Juvenile xanthogranuloma, frontal bone osteoma, and localized hypertrophic neuropathy of the supraorbital nerve (n = 1 each) were treated by resection with good visual and cosmetic outcomes. CONCLUSIONS: Proptosis accompanied by visual loss is an uncommon presentation in children and suggests an orbital tumor. We found that visual outcome was better when the nerve was not involved by tumor. Optic nerve glioma was the most common cause and failed to respond to various treatments. Catheterization for arteriovenous malformation did not prevent proptosis, and final visual acuity fluctuated. Surgery for rhabdomyosarcoma and xanthogranuloma led to remission with preservation of vision in 2 of 3 cases.

The Need to Look for Visual Deficit After Stroke in Children.

Purpose: To evaluate the role of the ophthalmologist in the management of children with arterial stroke, at presentation and during follow-up. Methods: This retrospective case series comprised children with arterial stroke who were followed for at least 12 months in a tertiary pediatric medical center in 2005-2016. Demographic data and findings on radiological neuroimaging and ophthalmological and neurological examination were retrieved from the medical files. Results: The cohort included 26 children with stroke. Underlying disorders included metabolic syndrome (n = 5, 19.2%), cardiac anomaly or Fontan repair (n = 3 each, 11.5%), vascular anomaly (n = 3, 11.5%), head trauma with traumatic dissection (n = 3, 11.5%), and hypercoagulability (n = 1, 3.8%); in eight patients (30.8%), no apparent cause was found. Eleven patients (42.3%) had a non-ophthalmological neurological deficit as a result of the stroke. Eye examination was performed in nine patients (34.6%) during follow-up. Ophthalmological manifestations included hemianopic visual field defect in seven patients (7.7%) and complete blindness and poor visual acuity in one patient each (3.8%). At the last visit, no change in visual function was detected. Conclusion: The variable etiology and presentation of pediatric stroke may mask specific visual signs. Children with arterial stroke should be referred for early ophthalmological evaluation and visual rehabilitation.

Conservative management for pediatric patients with chiari 1 anomaly: A retrospective study.

OBJECTIVE: To better understand the natural history of non-surgical management of chiari 1 anomaly. PATIENTS AND METHODS: After obtaining approval of the institutional review board, medical records and radiological exams of patients treated for CM1 at our institution between the years 2010 and 2016 were reviewed. Twenty-nine patients total were included in our study. RESULTS: The average age of our patient population was 8.5 years old at the time of diagnosis. The average tonsillar herniation on first MRI was 9.4 mm (+/- 4.6) and the average tonsillar herniation on second MRI was 10.4 mm (+/- 4.8). The average follow up time of our sample of patients was 26 months. Of the 29 patients in our study 9 (31 %) had symptomatic presentation. Interestingly, four of our patients (13.8 %) presented with epilepsy. CONCLUSIONS: Our findings support the previous work that nonoperative management is best in asymptomatic or mildly symptomatic chiari patients.

Protective Effect of TLR4 Ablation against Corneal Neovascularization following Chemical Burn in a Mouse Model.

PURPOSE: To determine whether Toll-like receptor 4 knockout protects mice from corneal neovascularization following chemical injury compared to wild-type (WT) mice. METHODS: A chemical burn (75% silver nitrate, 25% potassium nitrate) was created under anesthesia in the central right cornea of 32 WT and 31 Toll-like receptor 4 knockout mice. Corneal neovascularization was evaluated at 3, 4, 6, 8, 10, and 35 days after injury using digital photography, fluorescein angiography, gelatin perfusion with fluorescence vascular imaging, immunofluorescence staining, and molecular analysis. RESULTS: There was no significant between-group difference in relative corneal burn area at 10 days after injury (39.0 ± 2.4% vs. 38.8 ± 9.8%, respectively). Neovascularization was detected in all corneas in vivo and perfusion was detected by fluorescence vascular imaging, reaching maximum area on day 10. The relative area of neovascularization was significantly smaller in the knockout than the WT mice on days 6 (33.3 ± 4.2% vs. 46.8 ± 7.4%, respectively, p = 0.005) and 8 (36.6 ± 1.1% vs. 52.2 ± 6.4%, respectively, p = 0.027), although neovascularization was intensive in both groups. In line with the immunostaining findings of angiogenesis and inflammatory infiltration of damaged corneas, molecular analysis (performed on day 3) revealed elevated expression levels of angiogenesis-related genes (vascular endothelial growth factor, VEGFR2, VEGFR1) and inflammation-related genes (CD45 and TGFß1) in the WT mice. The knockout mice had higher TNF-α expression than the WT mice. CONCLUSION: In a mouse corneal chemical burn model, lack of Toll-like receptor 4 expression did not completely inhibit angiogenesis, but did have a relative effect to reduce neovascularization as compared to the WT.

MicroRNA-mRNA expression profiles associated with medulloblastoma subgroup 4.

PURPOSE: Medulloblastoma (MB), the most common malignant brain tumor in children, is divided into four tumor subgroups: wingless-type (WNT), sonic hedgehog (SHH), Group 3, and Group 4. Ideally, clinical practice and treatment design should be subgroup specific. While WNT and SHH subgroups have well-defined biomarkers, distinguishing Group 3 from Group 4 is not straightforward. MicroRNAs (miRNAs), which regulate posttranscriptional gene expression, are involved in MB tumorigenesis. However, the miRNA-messenger RNA (mRNA) regulatory network in MB is far from being fully understood. Our aims were to investigate miRNA expression regulation in MB subgroups, to assess miRNA target relationships, and to identify miRNAs that can distinguish Group 3 from Group 4. PATIENTS AND METHODS: With these aims, integrated transcriptome mRNA and miRNA expression analysis was performed on primary tumor samples collected from 18 children with MB, using miRNA sequencing (miRNA-seq), RNA sequencing (RNA-seq), and quantitative PCR. RESULTS: Of all the expressed miRNAs, 19 appeared to be significantly differentially expressed (DE) between Group 4 and non-Group 4 subgroups (false discovery rate [FDR] <0.05), including 10 miRNAs, which, for the first time, are reported to be in conjunction with MB. RNA-seq analysis identified 165 genes that were DE between Group 4 and the other subgroups (FDR <0.05), among which seven are predicted targets of five DE miRNAs and exhibit inverse expression pattern. CONCLUSION: This study identified miRNA molecules that may be involved in Group 4 etiology, in general, and can distinguish between Group 3 and Group 4, in particular. In addition, understanding the involvement of miRNAs and their targets in MB may improve diagnosis and advance the development of targeted treatment for MB.

Optic pathway-hypothalamic glioma hemorrhage: a series of 9 patients and review of the literature.

OBJECTIVEHemorrhage (also known as apoplexy) in optic pathway gliomas (OPGs) is rare. Because of the variable presentations and low incidence of OPG hemorrhages, little is known about their clinical course and the best treatment options. The aim of this work was to review risk factors, clinical course, and treatment strategies of optic glioma hemorrhages in the largest possible number of cases.METHODSA total of 34 patients were analyzed. Nine new cases were collected, and 25 were identified in the literature. Data regarding demographics, radiological and histological features, treatment, and outcome were retrospectively reviewed.RESULTSThe majority of patients were younger than 20 years. Only 3 patients were known to have neurofibromatosis. The histopathological diagnosis was pilocytic astrocytoma in the majority of cases. Five patients had intraorbital hemorrhages, whereas 29 patients had intracranial hemorrhage; the majority of intracranial bleeds were treated surgically. Six patients, all with intracranial hemorrhage, died due to recurrent bleeding, hydrocephalus, or surgical complications. No clear risk factors could be identified.CONCLUSIONSIntracerebral OPG hemorrhages have a fatal outcome in 20% of cases. Age, hormonal status, neurofibromatosis involvement, and histopathological diagnosis have been suggested as risk factors for hemorrhage, but this cannot be reliably established from the present series. The goals of surgery should be patient survival and prevention of further neurological and ophthalmological deterioration.

Use of Optical Coherence Tomography to Detect Retinal Nerve Fiber Loss in Children With Optic Pathway Glioma.

Optic pathway glioma (OPG) presents in childhood and can cause significant morbidity and visual loss. Magnetic resonance imaging (MRI) is the current imaging modality of choice for evaluation of OPG progression, but it is a relatively limited resource often requiring sedation in the pediatric age group. Additionally, OPG progression on MRI does not always correlate with clinical progression. As a result, several other modalities for evaluating OPG are being investigated, including optical coherence tomography (OCT), a readily available imaging technique in ophthalmic practice. The purpose of the present study was to examine the association between retinal nerve fiber layer (RNFL) thickness measured using OCT and optic nerve function in children with OPG with and without neurofibromatosis-1 (NF-1). A retrospective chart review was conducted to identify children diagnosed with OPG from 2001 to 2015 at a tertiary pediatric medical center. The correlation between OCT measurements and clinical visual parameters was statistically analyzed. Included were 23 children with imaging-confirmed OPG and spectral domain OCT: 10 with NF-1 (mean age at diagnosis 5.8 years) and 13 without (mean age at diagnosis 5.9 years). The glioma involved the chiasma-hypothalamus in 19 patients, optic nerve in 11, and optic tract in 7; more than one anatomic site was affected in 15. Symptoms were reported in 2 patients with NF-1 and most patients without NF-1. Visual field defects included monocular, bitemporal, nasal, and homonymous hemianopia. Initial mean RNFL was 85.4 µm in the NF-1 group and 65 µm in the non-NF-1 group. Visual acuity deteriorated in 1/10 patients and 5/13 patients, respectively. Repeated OCT showed continued RNFL thinning in 3 patients (5 eyes) in the NF-1 group and in 8 patients (11 eyes) in the non-NF-1 group, often associated with a decrease in optic nerve function. In conclusion, visual function in children with OPG is correlated with repeated OCT measurements and weakly with neuroimaging. Children without NF-1 are usually symptomatic and have a worse clinical outcome. These findings may have important implications when considering initiating, continuing or stopping chemotherapy for OPG. The application of OCT in the assessment of OPG and the correlation of the findings to clinical progression can have a significant impact on OPG patient management.

Long-term follow-up of benign positional vertical opsoclonus in infants: retrospective cohort.

BACKGROUND/AIMS: Benign positional vertical opsoclonus in infants, also described as paroxysmal tonic downgaze, is an unsettling phenomenon that leads to extensive work-up, although benign course has been reported in sporadic cases. We describe long-term follow-up of a series of infants with the phenomenon. METHODS: This retrospective cohort included all infants diagnosed with rapid downgaze eye movement in 2012-2015 and followed until 2016. The databases of two medical centres were retrospectively reviewed. Benign positional vertical opsoclonus was diagnosed based on clinical findings of experienced neuro-ophthalmologists. Data were collected on demographics, symptoms and signs, neuro-ophthalmological and neurological evaluations, and outcome. Imaging studies were reviewed. Main outcome measures were long-term outcome and findings of the thorough investigation. RESULTS: The cohort included six infants. All infants were born at term. Age at presentation was several days to 12 weeks. Episodes lasted a few seconds and varied in frequency from <10 to dozens per day. In five infants, symptoms occurred in the supine position. There was a wide variability in the work-up without any pathological findings. Follow-up ranged from 1 to 2.5 years. Ocular symptoms gradually decreased until resolution. Infants reached normal developmental milestones. CONCLUSIONS: Our identification of six patients in only 3 years suggests benign positional vertical opsoclonus may be more prevalent than previously described. In our experience, it affects otherwise healthy infants and resolves spontaneously. In view of the good long-term outcome, a comprehensive clinical investigation may not be necessary.

Fluorescence Lifetime Imaging Microscopy, a Novel Diagnostic Tool for Metastatic Cell Detection in the Cerebrospinal Fluid of Children with Medulloblastoma.

In pediatric brain tumours, dissemination of malignant cells within the central nervous system confers poor prognosis and determines treatment intensity, but is often undetectable by imaging or cytology. This study describes the use of fluorescence lifetime (FLT) imaging microscopy (FLIM), a novel diagnostic tool, for detection of metastatic spread. The study group included 15 children with medulloblastoma and 2 with atypical teratoid/rhabdoid tumour. Cells extracted from the tumour and the cerebrospinal fluid (CSF) 2 weeks postoperatively and repeatedly during chemo/radiotherapy were subjected to nuclear staining followed by FLT measurement and cytological study. Control CSF samples were collected from patients with infectious/inflammatory disease attending the same hospital. Median FLT was prolonged in tumour cells (4.27 ± 0.28 ns; P < 2.2*10-16) and CSF metastatic cells obtained before chemo/radiotherapy (6.28 ± 0.22 ns; P < 2.2*10-16); normal in inflammatory control cells (2.6 ± 0.04 ns) and cells from children without metastasis before chemo/radiotherapy (2.62 ± 0.23 ns; P = 0.858) and following treatment (2.62 ± 0.21 ns; P = 0.053); and short in CSF metastatic cells obtained after chemo/radiotherapy (2.40 ± 0.2 ns; P < 2.2*10-16). FLIM is a simple test that can potentially identify CSF spread of brain tumours. FLT changes in accordance with treatment, with significant prolonged median values in tumours and metastases. More accurate detection of metastatic cells may guide personalised treatment and improve the therapeutic outcome.

Distal shunt revision: a simple method to avoid repeat laparotomy.

Hydrocephalus is usually treated by placement of a ventriculo-peritoneal (VP) shunt. Distal VP shunt failure is a common complication of this procedure, especially in the paediatric population. Distal shunt revisions are often made more technically difficult by challenging abdominal anatomy. In this technical note, we describe a simple technique utilizing tenting sutures and the previous shunt tract for placement of the distal abdominal catheter accurately into the peritoneal space during distal shunt revision.

The promise of stem cell-based therapeutics in ophthalmology.

The promising role of cellular therapies in the preservation and restoration of visual function has prompted intensive efforts to characterize embryonic, adult, and induced pluripotent stem cells for regenerative purposes. Three main approaches to the use of stem cells have been described: sustained drug delivery, immunomodulation, and differentiation into various ocular structures. Studies of the differentiation capacity of all three types of stem cells into epithelial, neural, glial and vascular phenotypes have reached proof-of-concept in culture, but the correction of vision is still in the early developmental stages, and the requirements for effective in vivo implementation are still unclear. We present an overview of some of the preclinical findings on stem-cell rescue and regeneration of the cornea and retina in acute injury and degenerative disorders.

Paradoxical ventriculomegaly due to low-pressure hydrocephalus, a rare complication of the treatment of a trapped fourth ventricle: Case report.

In this paper, we describe the rare phenomena of descending transtentorial herniation and paradoxical ventriculomegaly due to low pressure hydrocephalus. This resulted as a complication of treatment in a 14year old male patient, who had undergone multiple ventriculo-peritoneal shunt placements for hydrocephalus after resection of pilocytic astrocytoma. We discuss the etiology of this rare complication and our strategy for treatment. We emphasize the need for strategic placement of programmable shunts to avoid over shunting and associated complications such as tentorial herniation.

Comparison of Neuroprotective Effect of Bevacizumab and Sildenafil following Induction of Stroke in a Mouse Model.

To evaluate the effect of bevacizumab and sildenafil on stroke parameters in a mouse model, middle cerebral artery occlusion was induced in male C57Bl/6 mice using an intra-arterial filament method. The filament was removed after 60 minutes, and the mice were immediately given a single intraperitoneal injection of saline, bevacizumab, or sildenafil. An additional group of mice (n = 7) received bevacizumab 6 h after MCAO induction. The mice were euthanized 24 hours later and evaluated for infarct area and brain edema using triphenyltetrazolium chloride staining and ImageJ. In the saline-treated mice (n = 16), total stroke volume was 19.20 ± 6.38 mm(3), mean penumbra area was 4.5 ± 2.03 mm(3), and hemispheric asymmetry was 106.5%. Corresponding values in the bevacizumab group (n = 19) were 17.79 ± 5.80 mm(3), 7.3 ± 3.5 mm(3), and 108.6%; in the delayed (6 h) bevacizumab injected mice (n = 7) they were 9.80 ± 8.00 mm(3), 2.4 ± 2.0 mm(3), and 98.2%; and in the sildenafil group (n = 16) they were 18.42 ± 5.41 mm(3), 5.7 ± 2.02 mm(3), and 109.9%. The bevacizumab group had a significantly larger mean penumbra area when given immediately and smaller total stroke area in both groups than the saline- (p = 0.03) and sildenafil-treated (p = 0.003) groups. Only delayed bevacizumab group had reduced edema. Bevacizumab, injected immediately or delayed after injury, exerts a neuroprotective/salvage effect, whereas immediate treatment with sildenafil does not. Inflammation may play a role in the neuroprotective effect.

Relative neuroprotective effects hyperbaric oxygen treatment and TLR4 knockout in a mouse model of temporary middle cerebral artery occlusion.

PURPOSE: To examine the effects of hyperbaric oxygen (HBO) therapy and knockout of toll-like receptor 4 (TLR4) on the outcome of temporary middle cerebral artery occlusion (MCAO) in a mouse model. MATERIALS AND METHODS: MCAO was induced in anesthetized male C57Bl/6 mice (WT) and TLR4 knockout mice (TLR4(-/-)) using an intra-arterial filament method. After 30 or 90 min, the filament was removed, and the mice were given either no treatment (WT and TLR4(-/-) groups) or HBO (WT only). Mice were euthanized 24 h after MCAO, and the brain infarct area was examined using 2,3,5-triphenyltetrazolium chloride (TTC) staining. RESULTS: In the WT group, without treatment, lesion volume was 120 ± 13 mm(3) in the mice subjected to 30 min' MCAO and 173 ± 23 mm(3) in the mice subjected to 90 min' MCAO. Respective values with HBO treatment were 66.5 ± 36.7 mm(3) and 53.2 ± 17.2 mm(3). The difference was significant only for 90-minute MCAO (p < 0.01, nonparametric test). In the TLR4(-/-) group (all untreated), lesion volume was 95.9 ± 17.9 after 90 min of MCAO, which was significantly lower than in the untreated WT animals (p < 0.05, nonparametric test). CONCLUSIONS: A single treatment of HBO immediately after MCAO followed by 24 h' reperfusion significantly reduces edema and may improve perfusion. TLR4 knockout protects mice from MCAO damage, but to a lesser extent than HBO treatment.

Difficulty in Distinguishing Posterior Reversible Encephalopathy Syndrome, Hypoxic-Ischemic Insult, and Acute Toxic Leukoencephalopathy in Children.

AIM: This study aims to describe our experience of unique pediatric neurological cases and associated difficulty in differentiating posterior reversible encephalopathy syndrome (PRES) from hypoxic-ischemic insult (HII), and acute toxic leukoencephalopathy (ATL). METHODS: The study included three children with a clinical picture suggestive of PRES, HII, and ATL of different etiologies who were diagnosed and treated at a tertiary pediatric medical center in 2011 to 2014. RESULTS: All patients presented with blindness following seizures with asphyxia/aspiration in a syndromatic child, too-rapid lipid infusion in a child with acute lymphoblastic leukemia, and repeated vomiting in a child with cerebral palsy, hydrocephalus, and malfunction of ventriculoperitoneal shunt. All patients had cortical blindness and high-signal foci in the cortical and subcortical regions on magnetic resonance imaging. All children improved. CONCLUSIONS: Familiarity with the clinical and radiological characteristics of neurological conditions leading to reversible cortical blindness is essential for diagnosis and management. Distinguishing PRES from HII and ATL can be challenging. Our cases most likely combined these etiologies, with the first patient diagnosed with PRES with HII, the second with PRES with ATL, and the third with focal HII. Given the diversity of the findings and the unclear prognostic significance, studies of the pathophysiology of PRES are warranted.