Significance of H3K27M mutation with specific histomorphological features and associated molecular alterations in pediatric high-grade glial tumors

PURPOSE

Pediatric high-grade gliomas (pHGGs) constitute almost 15% of all childhood brain tumors. Recurrent mutations such as H3K27M mutation in H3F3A and HIST1H3B genes encoding histone H3 and its variants were identified in approximately 30% of pediatric glioblastomas. This study aimed to ascertain the morphological and molecular characteristics of pHGGs with H3K27M mutation.

METHODS

In total, 61 cases of pHGGs (anaplastic astrocytoma, 12; glioblastomas, 49) from four university hospitals were studied. The histomorphological features were examined and immunohistochemistry was performed to evaluate the mutation status of H3K27M, ATRX, IDH1, BRAF V600E, and p53 genes.

RESULTS

The study comprised 25 females and 36 males (age range, 1-18 years) with a clinical follow-up of up to 108 months. From the total, 31 patients were positive for H3K27M mutation located in the midline, mostly in the pons and thalamus. H3K27M mutation was commonly associated with ATRX loss (32.3%) and p53 (74.2%) immunoreactivity with a co-expression rate of 25.8%. While IDH1 mutation was not detected in pHGGs with H3K27M mutation, BRAFV600E mutation was rarely observed. Among the various histomorphological features, increased number of mitosis, increased Ki-67 proliferation index, and palisading and geographical necrosis along with small cell patterns were significantly associated with the H3K27M wild-type tumors. Focal infarct-like necrosis and pilomyxoid morphology was significantly associated with these tumors.

CONCLUSION

H3K27M mutation occurs exclusively in pHGGs arising from the midline and presents with varied histomorphological features ranging from low-grade pilomyxoid astrocytoma to highly pleomorphic glioblastoma along with ATRX loss and p53 mutations.

The Acute and Delayed Effects of Vagal Nerve Stimulation on an Absence Epilepsy Model in WAG/Rij

AIM

Vagal nerve stimulation (VNS) is an effective method of treatment for epilepsy patients either unresponsive to medical therapy or not suitable for resective surgeries. We designed an experimental study on Wistar Albino Glaxo rats from Rijswijk (WAGRij) to investigate the effects of VNS on a non-convulsive epilepsy model.

MATERIAL AND METHODS

The experiment was performed on six WAG/Rij rats, a validated strain for genetic absence seizures. The animals were underwent VNS and the effects were investigated on electroencephalography (EEG) recordings at 22, 24, 26 hours of stimulation and 15 days after the cessation, for duration of spike and wave complexes (SWC), the numbers, mean duration of SWC and frequencies in an hour.

RESULTS

EEG recordings demonstrated that the mean duration of SWC was 353.1 seconds and the number of activity per hour was 62 at the baseline. There were statistically significant decreases in the total duration of SWC and the number of activities (61.8% and 78% decrease, respectively). There were no significant decreases in the mean duration of SWC and the frequencies.

CONCLUSION

The acute stimulation of the vagal nerve caused a statistically significant decrease both in overall duration of SWC and the number of complexes in an hour. Moreover, the positive effects seemed to last even 15 days after the cessation of the stimulation. Further studies focusing on different stimulation parameters and delayed effects of the VNS on human absence seizures are warranted.

Expression profiles of 151 pediatric low-grade gliomas reveal molecular differences associated with location and histological subtype

BACKGROUND

Pediatric low-grade gliomas (PLGGs), the most frequent pediatric brain tumor, comprise a heterogeneous group of diseases. Recent genomic analyses suggest that these tumors are mostly driven by mitogene-activated protein kinase (MAPK) pathway alterations. However, little is known about the molecular characteristics inherent to their clinical and histological heterogeneity.

METHODS

We performed gene expression profiling on 151 paraffin-embedded PLGGs from different locations, ages, and histologies. Using unsupervised and supervised analyses, we compared molecular features with age, location, histology, and BRAF genomic status. We compared molecular differences with normal pediatric brain expression profiles to observe whether those patterns were mirrored in normal brain.

RESULTS

Unsupervised clustering distinguished 3 molecular groups that correlated with location in the brain and histological subtype. "Not otherwise specified" (NOS) tumors did not constitute a unified class. Supratentorial pilocytic astrocytomas (PAs) were significantly enriched with genes involved in pathways related to inflammatory activity compared with infratentorial tumors. Differences based on tumor location were not mirrored in location-dependent differences in expression within normal brain tissue. We identified significant differences between supratentorial PAs and diffuse astrocytomas as well as between supratentorial PAs and dysembryoplastic neuroepithelial tumors but not between supratentorial PAs and gangliogliomas. Similar expression patterns were observed between childhood and adolescent PAs. We identified differences between BRAF-duplicated and V600E-mutated tumors but not between primary and recurrent PLGGs.

CONCLUSION

Expression profiling of PLGGs reveals significant differences associated with tumor location, histology, and BRAF genomic status. Supratentorial PAs, in particular, are enriched in inflammatory pathways that appear to be tumor-related.

The value of sacral skin lesions in predicting occult spinal dysraphism in children with voiding dysfunction and normal neurological examination

OBJECTIVE

The role of magnetic resonance imaging (MRI) in detecting occult spinal dysraphism (OSD) in children with voiding dysfunction and a normal neurological examination is still under debate. The aim of this study was to assess the correlation of sacral skin lesions with OSD detected on MRI, in a population of children with resistant lower urinary tract symptoms (LUTS).

PATIENTS AND METHODS

A total of 114 children over 5 years of age with urinary tract infection (UTI) and/or LUTS and normal neurological examination were enrolled. All children underwent sacral neurological examination, urine analysis and cultures, renal/bladder ultrasound, voiding cystourethrogram and urodynamic examination. After a treatment period of 6 months, the patients were re-evaluated and spinal MRI was performed in 61 with ongoing LUTS or UTI.

RESULTS

Nineteen of 61 children (31%) had cutaneous stigmas. MRI detected spinal abnormality in 2/42 children with a normal sacral examination in comparison to 7/19 children with an abnormal sacral finding (Chi-squared test, P < 0.005). The sensitivity and specificity of an abnormal sacral finding in predicting MRI abnormality were 0.76 and 0.77, respectively. Urodynamic parameters did not predict an abnormal spinal MRI.

CONCLUSIONS

Abnormal sacral findings, but not urodynamic studies, are strong predictors of OSD. A normal sacral examination does not rule out OSD.

Primary meningeal osteosarcoma of the brain during childhood. Case report

Primary meningeal osteosarcomas are rare tumors, with only 19 reported cases in the literature; only 4 of these, including the present case, are in pediatric patients. In this report, the authors present the case of an 8-year-old boy with a history of generalized tonic-clonic seizures who was found to harbor a meningeal osteosarcoma within the sylvian fissure. Initial working diagnoses included meningioma and glioma. After tumor enlargement and progressive symptoms, the patient underwent a large frontotemporal craniotomy and complete resection of the lesion, which recurred 6 and 12 months after the initial surgery and was surgically treated after each recurrence. The rarity of primary meningeal osteosarcomas can make their diagnosis difficult, and histopathological evaluation is mandatory for diagnosis. Because of their fast progression, they must be treated aggressively by means of surgery, chemotherapy, and radiotherapy.

Is the brain biopsy obligatory or not for the diagnosis of Schilder's disease? Review of the literature

BACKGROUND

Schilder's myelinoclastic diffuse sclerosis (Schilder's disease) is a rare demyelinating disorder. Clinical features and neuroimaging findings of this disease might mimic an intra-cranial mass lesion including an abscess or a tumour.

CASE REPORT

Clinical and radiological findings of two children with the diagnosis of Shilder's disease are reported, and the role of brain biopsy as a diagnostic tool is discussed.

New candidate chromosomal regions for chordoma development

BACKGROUND

Chordomas are rare, slow growing, infiltrative tumors thought to arise from vestigial or ectopic notochord. Chordoma can occur along the axial skeleton, predominantly in the sphenooccipital, vertebral, and sacrococcygeal regions. Although most chordomas are sporadic, familial cases have also been reported. The most common molecular cytogenetic abnormalities in these tumors are monosomy of chromosome 1 and gain of chromosome 7. In addition, a variety of other chromosomal changes, which are associated with losses and gains of different chromosomes, have also been described in chordomas, such as 1q, 2p, 3p, 5q, 9p, 10, 12q, 13q, 17, and 20q.

METHODS

In this study, using molecular cytogenetics (iFISH), we have studied 1p36, 1q25, 3p13-p14, 7q33, 17p13.1 (p53 gene locus), 2p13 (TGF-alpha locus), 6p12 (VEGF locus), and 4q26-q27 (bFGF/FGF2 locus) loci in chordoma tissues from seven patients with 7 primary tumors and 11 recurrences.

RESULTS

We found that chromosomes 1p36, 1q25, 2p13, and 7q33 are affected in primary chordomas, and these aberrations persist in recurrences. However, the chromosome 6p12 aberration was seen only in primary chordomas, but not in recurrences, indicating that this locus may be associated with chordoma genesis.

CONCLUSIONS

Our descriptive data from interphase FISH analyses suggest that future studies should incorporate a larger number of patients and should focus on identifying the candidate genes in chordoma pathogenesis. Such studies may use a whole-genomic approach, in addition to the regions identified in this study and others.

Atypical midline cleft with duplication of the metopic suture

INTRODUCTION

In contrast to the common clefts of the lip, alveolus and palate, the atypical clefts of the face may come in myriad patterns of clinical expression and are often not easy to define.

PURPOSE

In this report, a case of median craniofacial dysraphia is described.

PATIENT

At presentation, the 3-month-old male patient had a bilateral complete cleft of the lip, alveolus and palate. The nose was wide and a horn was present on the nasal dorsum. 3-D CT AND MRI REVEALED: Duplication of the metopic suture ending at the wide anterior fontanel; orbital hypertelorism; midline cranial cleft ending just superior to the nasal dorsum; frontoethmoidal encephalocoele and holoprosencephaly. The presence of two metopic sutures was confirmed during surgery.

CONCLUSION

The presented case carries the characteristics of the median cleft face syndrome. However, it differs from similar cases in two respects. First, the patient had two metopic sutures, one on either side of the cranial extension of the median cleft. Second, the patient had a bilateral cleft lip in contrast to the expected median cleft lip deformity.

Does Surgical Release of Secondary Spinal Cord Tethering Improve the Prognosis of Neurogenic Bladder in Children With Myelomeningocele?

PURPOSE

The diagnostic criteria for secondary tethering of the spinal cord in children with prior closure of an open spinal defect are not well defined. Urological, neurological or orthopedic deterioration during followup remains the only strong indicator for the diagnosis of this condition. However, the outcome of untethering surgery cannot always be predicted. The aim of this study was to determine neurourological outcome after secondary untethering surgery in children with myelomeningocele.

MATERIALS AND METHODS

Of 401 children with myelomeningocele followed at our multidisciplinary spina bifida clinic between 1996 and 2005, 56 (14%) were diagnosed with secondary tethering of the spinal cord (median age at diagnosis 4.1 years). The diagnosis was based on urological and neuro-orthopedic deterioration in 58% and 42% of children, respectively. Preoperative urological findings were compared with 6-month postoperative findings.

RESULTS

Febrile urinary tract infection, upper tract dilatation and vesicoureteral reflux were preoperatively documented in 48.2%, 19% and 30% of the 56 children, respectively. At 6 months postoperatively urine cultures were sterile in 34% of patients and upper tract dilatation completely resolved in 45%. For all grades of vesicoureteral reflux complete resolution occurred in 47% of patients. Urodynamic parameters in terms of cystometric bladder capacity and detrusor leak point pressure substantially improved 6 months after untethering surgery (125 vs 170 ml and 69.1 vs 47.5 cm H2O, respectively, p < 0.05). Assessment of urodynamic findings in 19 children at 1 year failed to demonstrate a significant change in these parameters. A subgroup analysis according to patient age at untethering surgery revealed urodynamic improvement was more significant in children who were diagnosed and treated before age 7 years.

CONCLUSIONS

Secondary tethering of the spinal cord is a major risk factor for urological and neurological deterioration in children with myelomeningocele. Close urological surveillance remains the most valuable tool in the early diagnosis. Our study shows that secondary untethering surgery may significantly improve urological outcome.

The Timing of Primary Neurosurgical Repair Significantly Affects Neurogenic Bladder Prognosis in Children With Myelomeningocele

PURPOSE

The correlation between timing of the primary neurosurgical repair and urological prognosis in infants with open spinal dysraphism remains unknown. We investigated the impact of primary repair timing on neurogenic bladder prognosis in children with myelomeningocele.

MATERIALS AND METHODS

We retrospectively reviewed the records of 401 children with myelomeningocele followed at our multidisciplinary clinic between 1996 and 2005. Among these patients 129 were included in the study based on the availability of urological followup data at age 3 years, which was chosen as an ideal point for the standardization of urological findings. Children were assigned to 1 of 2 groups-those who underwent primary neurosurgical repair within 72 hours of delivery (group 1) and those undergoing repair after 72 hours (group 2). We compared the incidence of febrile urinary tract infections, hydronephrosis, vesicoureteral reflux and secondary tethering of the spinal cord at age 3 years, as well as cystometric bladder capacity and detrusor leak point pressure between the 2 groups.

RESULTS

Urological followup data at age 3 years revealed significantly increased incidence of febrile urinary tract infections, vesicoureteral reflux, hydronephrosis and secondary tethering of the spinal cord in children in group 2 compared to group 1 (chi-square, p < or =0.05 for all comparisons). Urodynamic assessment also showed a significantly lower bladder capacity and a substantially higher detrusor leak point pressure in children who received primary repair at later than 72 hours (t test, p <0.05). A subgroup analysis of group 1 comparing children who underwent repair before and after 24 hours following delivery failed to demonstrate any significant difference in terms of febrile urinary tract infections, vesicoureteral reflux, hydronephrosis and secondary tethering (chi-square, p >0.05 for all comparisons), whereas mean bladder capacity was significantly higher (t test, p <0.05) and mean detrusor leak point pressure was lower (t test, p = 0.08) in children undergoing repair within 24 hours of delivery.

CONCLUSIONS

The timing of primary neurosurgical repair has a significant impact on neurogenic bladder prognosis in children with myelomeningocele. Closure of the spinal lesion on the first day of life seems to provide the best chance for favorable lower urinary tract function.

Antidepressant-like effect of hyperbaric oxygen treatment in forced-swimming test in rats

The present study was undertaken to assess the antidepressant-like activity of hyperbaric oxygen (HBO) treatment and also to investigate whether in the forced-swimming test HBO treatment interacts with the antidepressant effects of fluoxetine, a selective serotonin reuptake inhibitor, and imipramine, which is mainly a noradrenaline reuptake inhibitor. HBO treatment (at 2.4 atmospheres absolute [ATA] for 60 min) significantly reduced the immobility time in this test; in other words, it displayed antidepressant-like activity. The coadministration of HBO with fluoxetine (5 mg/kg) or imipramine (5 mg/kg) at their ineffective doses produced greater inhibition of immobility time compared with HBO alone. In conclusion, HBO treatment might be an alternative approach to antidepressant therapy, alone or in combination with antidepressant drugs.

L-NAME prevents anxiety-like and depression-like behaviour in rats exposed to restraint stress

Stressful life events contribute to the development of many neuropsychiatric disorders including depression and anxiety. Animal studies based on the relationship of stress and depression or anxiety are scarce and controversial. Moreover, neither the neurobiological basis of anxiety and depression nor the mechanisms responsible for neurochemical regulation by stressful stimuli are well understood. This study was designed to investigate the possible contribution of both acute (2 h) and chronic (2 h X 15 d) restraint stress in the generation of anxiety and depression, and also to find out whether nitric oxide (NO) has a modulatory role in these behavioral reactions. Elevated plus-maze and forced swimming test (FST) were chosen for assessment of anxiety and depression, respectively, and N(G)-nitro L-arginine methyl ester (L-NAME, 10 mg/kg), a NO synthase (NOS) inhibitor, and L-arginine (50 mg/kg), a NO precursor, were used to evaluate the role of nitrergic system in restraint exposed rats. The results showed that acute and chronic stress caused depression-like and anxiety-like behaviors in rats and the acute inhibition of NOS by L-NAME prevented these acute and chronic stress-induced anxiogenesis and depression. These data lead to the conclusion that stress and NO seem to be involved in the generation of anxiety and depression.

Cerebral venous malformations have distinct genetic origin from cerebral cavernous malformations

BACKGROUND AND PURPOSE

Pathogenesis of cerebral venous malformation (CVM) is unknown. Because of coexistence of CVM and cerebral cavernous malformations (CCM), some studies have suggested that these 2 entities share a common origin and pathogenetic mechanism.

METHODS

We have identified and ascertained over 200 families with CCM. Among these, 1 unique family was found to have members affected by both disorders. We have performed mutational analysis in all 3 CCM genes, KRIT1, Malcavernin, and PDCD10, to identify the causative gene in the family.

RESULTS

Mutational analysis revealed a frameshift mutation affecting exon 19 of the CCM1 gene (KRIT1) in members with CCM, whereas no such mutation was observed in the member with CVM.

CONCLUSIONS

These findings support the hypothesis that CVM and CCM are 2 distinct entities with different pathogenetic mechanisms. This data further supports the hypothesis that CVM has a distinct biology and clinical behavior when compared to CCM. CVM is a benign developmental anomaly and should be managed separately from CCM.

Lateral approach for resection of the C3 corpus: technical case report

OBJECTIVE AND IMPORTANCE

The C3 level is the transition zone between the upper and lower cervical spine. Because of its high position and anatomic relationships to significant structures, exposing C3 is challenging, and the surgical approach is controversial.

CLINICAL PRESENTATION

A 16-year-old girl was admitted to our institution with a 3-year history of neck pain and progressive quadriparesis. Neuroradiological examination revealed severe spinal cord compression from kyphosis at the C3 level.

TECHNIQUE

We used the lateral approach to resect the C3 corpus and realign the cervical spine. Resecting the transverse processes of C2-C4 and mobilizing the V2 segment of the vertebral artery adequately exposed C3 for resection. Bilateral occipitocervical fusion was performed in a second procedure, and no postoperative complications occurred. The patient's neurological status improved drastically after surgery, and she has had no craniocervical instability during the follow-up period.

CONCLUSION

The lateral approach to the C3 corpus offers the greatest degree of cord decompression and easy access to the lesion in a wide and sterile operative field. We describe the surgical technique of this approach as an alternative to the anterior transmucosal or anterolateral retropharyngeal approach.

Protective effects of dextromethorphan and tizanidine on ouabain-induced arrhythmias

The effects of the opioid agonist dextromethorphan and the alpha 2-adrenoceptor agonist tizanidine on ouabain-induced cardiac arrhythmias were investigated in rats. Ouabain (10 mg/kg i.v.) elicited ventricular arrhythmias in all of the control rats. Administration of dextromethorphan (25 mg/kg i.v.) and tizanidine (0.1 mg/kg i.v.) 30 min before ouabain treatment significantly reduced the incidence of arrhythmias. We suggest that dextromethorphan and tizanidine showed these effects by decreasing excitatory amino acid (EAA) activity. It can be speculated that opioids and other EAA antagonists may have antiarrhythmic actions through both their central and peripheral effects as well.

Therapeutic drug monitoring in Turkey: experiences from Istanbul

Therapeutic drug monitoring (TDM) has assumed an important place in patient management in the last few decades. In this study, serum drug levels determined in 7759 specimens sent to the Department of Pharmacology and Clinical Pharmacology in 1994 and 1998 for TDM were retrospectively evaluated. Monitored drugs were carbamazepine, valproate, phenytoin, phenobarbital, digoxin, theophylline, and salicylate. The comparison of the results obtained for the relevant 2 years showed that there was a remarkable increase in the number of requests for TDM per year and in the rate of serum drug levels that were within therapeutic range. Serum antiepileptic drug level monitoring accounted for a major part of the data. Overall data suggest that the use of TDM in antiepileptic drugs is improving; conversely, digoxin and theophylline are still not being properly monitored. In this study, the results are discussed in the light of rational TDM criteria.

Neonatal intracranial hemorrhage due to rupture of arteriovenous malformation

Two cases of neonatal intracerebral hemorrhage secondary to rupture of arteriovenous malformation are reported and the pertinent literature is reviewed. Despite the limited number of cases, review of the literature and our results demonstrate that the outcome of surgical removal of an arteriovenous malformation in the neonatal period is not as poor as was previously believed.

Intermittent diplopia in chordoma

The symptoms and findings of three patients with clivus chordomas who had episodes of intermittent diplopia are presented. The causes of intermittent diplopia are reviewed, and the possible mechanisms of this symptom in chordomas are discussed.

The plated bayonet: a new instrument to facilitate surgery for intra-axial neoplasms of the spinal cord and brain stem. Technical note

A new instrument for use in surgically treating intra-axial neoplasms of the spinal cord and brain stem is described. The plated bayonet allows neoplastic tissue in the spinal cord to be separated from functioning neural elements without perforating the adjacent spinal cord. In addition, the plated bayonet facilitates exposure through the very small incision necessary to remove tumors of the brain stem without damaging cranial nerves or other vital structures.