ATRX immunohistochemistry can help refine 'not elsewhere classified' categorisation for grade II/III gliomas.

Purpose: The 2016 WHO tumour classification highlights the role of IDH1/2 gene mutation and 1p/19q co-deletion in classifying grade II/III gliomas. A recent cIMPACT-NOW update proposes the use of the term 'Not Elsewhere Classified' (NEC) for IDH-mutant, non co-deleted tumours. Here we show how the incorporation of ATRX immunohistochemistry can be used to better delineate the NEC group. Methods: Clinical data was collected for 112 patients (59% male) treated at our unit. Mutations in IDH1/2 genes were detected by pyrosequencing or immunohistochemistry, 1p/19q co-deletion was assessed with fluorescence in situ hybridisation and ATRX status was determined using immunohistochemical techniques. Tumours were grouped on the basis of molecular markers and outcomes compared. Results: The mean age of diagnosis was 42.6 years (20-73 years). There were 88 oligodendrogliomas (II = 47, III = 41), 18 diffuse astrocytomas (II = 9, III = 9) and 6 oligoastrocytomas (II = 4, III = 2). The majority of gliomas (87.5%) had mutations in IDH1/2. 1p/19q co-deletion was significantly associated with oligodendroglial morphology (p = < 0.001) and was mutually exclusive with ATRX mutation. Classification on the basis of molecular information showed a significant different in survival between the groups. Conclusions: ATRX immunohistochemisty is a useful adjunct which can be used with IDH mutation status, 1p/19q co-deletion and histological findings to further define tumour groups. More work is needed to understand the molecular profiles and prognostic implications for non co-deletion, ATRX preserved cases.

Control tissue in brain banking: the importance of thorough neuropathological assessment.

Historically, control brain tissue was classified as such mainly by clinical history, and underwent limited neuropathological analysis. Significant progress has been made in recent years with the collection of more extensive clinical information and more specific classifications of neurodegenerative disease, aided by advances in histological processing and increasingly sensitive detection methods. We hypothesised that this may have resulted in certain pathologies previously going unidentified, due to insufficient block sampling and an inadequate range of stains, resulting in the disease not being recognised. We therefore investigated the significance of changes to our own protocols for examining control brain tissue before and after 2007. Control cases that were originally assessed before 2007 were re-assessed using our current staining protocol and antibodies, and compared with age-matched cases post-2007. We found that almost all cases that were originally described as neuropathologically normal displayed some level of pathology after re-analysis, with four cases displaying what we have termed 'major' pathology that previously went unidentified, emphasising on a small scale the importance of accurate neuropathological analysis of control tissue, and highlighting the inherent difficulty of traditionally classifying tissue simply as 'disease' or 'control'. We hope our findings will stimulate debate within the brain banking community, with the eventual aim being standardisation of protocols for assessing controls across brain banks.

Neuropathology of the hippocampus in FTLD-Tau with Pick bodies: a study of the BrainNet Europe Consortium.

AIMS: Frontotemporal lobar degeneration with Pick bodies (Pick's disease) is characterized by the presence of tau immunoreactive spherical structures in the cytoplasm of neurones. In view of confusion about the molecular pathology of Pick's disease, we aimed to evaluate the spectrum of tau pathology and concomitant neurodegeneration-associated protein depositions in the characteristically affected hippocampus. METHODS: We evaluated immunoreactivity (IR) for tau (AT8, 3R, 4R), α-synuclein, TDP43, p62, and ubiquitin in the hippocampus, entorhinal and temporal cortex in 66 archival cases diagnosed neuropathologically as Pick's disease. RESULTS: Mean age at death was 68.2 years (range 49-96). Fifty-two (79%) brains showed 3R immunoreactive spherical inclusions in the granule cells of the dentate gyrus. These typical cases presented mainly with the behavioural variant of frontotemporal dementia, followed by progressive aphasia, mixed syndromes or early memory disturbance. α-Synuclein IR was seen only in occasional spherical tau-positive inclusions, TDP-43 IR was absent, and 4R IR was present only as neurofibrillary tangles in pyramidal neurones. Aß IR was observed in 16 cases; however, the overall level of Alzheimer's disease-related alterations was mainly low or intermediate (n = 3). Furthermore, we identified six cases with unclassifiable tauopathy. CONCLUSIONS: (i) Pick's disease may occur also in elderly patients and is characterized by a relatively uniform pathology with 3R tau inclusions particularly in the granule cells of dentate gyrus; (ii) even minor deviation from these morphological criteria suggests a different disorder; and (iii) immunohistological revision of archival cases expands the spectrum of tauopathies that require further classification.

Diffuse form of dysembryoplastic neuroepithelial tumour: the histological and immunohistochemical features of a distinct entity showing transition to dysembryoplastic neuroepithelial tumour and ganglioglioma.

AIMS: A diffuse variant of dysembryoplastic neuroepithelial tumour (dDNT) has previously been described, which although composed of oligodendroglia-like cells (OLC), astrocytes and mature neurones, lacks the multinodularity and 'specific component' of typical DNT. The dDNT poses a significant challenge to the neuropathologist. This study was undertaken to further characterize the histological and immunohistochemical features of dDNT. MATERIALS AND METHODS: Review of our archived material from epilepsy surgery identified 16 cases, in which features of dDNT predominated. Their histological and immunohistochemical features, including CD34 and nestin immunohistochemistry, were analysed. RESULTS: Seven cases had the characteristics of pure dDNT. A further two cases of dDNT showed extension into the white matter with occasional dysplastic neurones. Two additional cases had similar features but with the presence of either single, or multiple small nodular clusters of OLC, in keeping with transition to classical DNT. Five cases showed ganglioglioma-like areas, of which three cases had micronodule formation but with predominant dDNT pattern. In all the cases the dDNT areas showed strong CD34 and less intense nestin immunoreactivity and microglial activation highlighting the full extent of the lesions. There was variable overlap between CD34 and nestin positivity within the micronodular and/or ganglioglioma-like areas. CONCLUSIONS: Immunoreactivity for CD34 and nestin characterizes the dDNT and helps to distinguish it from other lesions associated with epilepsy. Histological evidence indicative of transition of dDNT to other forms of DNT and ganglioglioma suggests that dDNT might be an early histogenetic form of these glioneuronal tumours.

Chicken dendritic cells and type II pneumocytes express a common intracellular epitope.

1. CVI-ChNL 74·3, a dendritic cell-specific monoclonal antibody (mAb) also identifies chicken lung granular pneumocytes (type II pneumocytes), which produce surfactant. 2. The 74·3 mAb does not cross-react with any other avian or mammalian granular pneumocyte, and provides a convenient tool for monitoring the status of type II pneumocytes in the chicken lung.

The histopathological spectrum of malignant hyperthermia and rhabdomyolysis due to RYR1 mutations.

OBJECTIVE: The histopathological features of malignant hyperthermia (MH) and non-anaesthetic (mostly exertional) rhabdomyolysis (RM) due to RYR1 mutations have only been reported in a few cases. METHODS: We performed a retrospective multi-centre cohort study focussing on the histopathological features of patients with MH or RM due to RYR1 mutations (1987-2017). All muscle biopsies were reviewed by a neuromuscular pathologist. Additional morphometric and electron microscopic analysis were performed where possible. RESULTS: Through the six participating centres we identified 50 patients from 46 families, including patients with MH (n = 31) and RM (n = 19). Overall, the biopsy of 90% of patients showed one or more myopathic features including: increased fibre size variability (n = 44), increase in the number of fibres with internal nuclei (n = 30), and type I fibre predominance (n = 13). Abnormalities on oxidative staining, generally considered to be more specifically associated with RYR1-related congenital myopathies, were observed in 52%, and included unevenness (n = 24), central cores (n = 7) and multi-minicores (n = 3). Apart from oxidative staining abnormalities more frequently observed in MH patients, the histopathological spectrum was similar between the two groups. There was no correlation between the presence of cores and the occurrence of clinically detectable weakness or presence of (likely) pathogenic variants. CONCLUSIONS: Patients with RYR1-related MH and RM exhibit a similar histopathological spectrum, ranging from mild myopathic changes to cores and other features typical of RYR1-related congenital myopathies. Suggestive histopathological features may support RYR1 involvement, also in cases where the in vitro contracture test is not informative.

Sarcoidosis presenting as an isolated extradural thoracolumbar lesion mimicking tumour.

A 44-year-old woman presented with a single large extradural spinal lesion, mimicking schwannoma, as the first and only manifestation of sarcoidosis. She underwent total macroscopic excision. Four months later she was neurologically intact, with no radiological evidence of recurrence.

Masson's tumour in the right parietal lobe after stereotactic radiosurgery for cerebellar AVM: case report and review.

We present a 50-year-old patient who had undergone stereotactic radiosurgery for a cerebellar vermian arteriovenous malformation. On routine surveillance MR imaging a lesion suggestive of a meningioma was demonstrated and removed. Histologically it was found to be intravascular papillary endothelial hyperplasia (Masson's tumour). The characteristic radiological and histological findings are presented. Aspects of management of this rare tumour are discussed. Given that cases are often found in combination with a vascular abnormality, we discuss the possibility of a change in local haemodynamics after radiosurgery promoting development of this tumour.

Possible mechanisms for sensorineural hearing loss and deafness in patients with propionic acidemia.

Propionic acidemia is an inborn error of metabolism caused by deficiency of the mitochondrial enzyme propionyl-CoA carboxylase. Sensorineural deafness and severe hearing loss have been described as long-term complications of this disease, however, the mechanism has not yet been elucidated. We have recently shown by patch clamping experiments and Western blots that acute and chronic effects of accumulating metabolites such as propionic acid, propionylcarnitine and methylcitrate on the KvLQT1/KCNE1 channel complex cause long QT syndrome in patients with propionic acidemia by inhibition of K+ flow via this channel. The same KvLQT1/KCNE1 channel complex is expressed in the inner ear and essential for luminal potassium secretion into the endolymphatic space. A disruption of this K+ flow results in sensorineural hearing loss or deafness. It can be assumed that acute and chronic effects of accumulating metabolites on the KvLQT1/KCNE1 channel protein may similarly cause the hearing impairment of patients with propionic acidemia.

A Ca(2+)-dependent transgenic model of cardiac hypertrophy: A role for protein kinase Calpha.

BACKGROUND: Calcium imbalances have been implicated as an underlying mechanism of human cardiac dysfunction. The voltage-dependent calcium channel plays a critical role in calcium regulation in the heart. Thus, aberrant calcium signaling arising from this channel could initiate the calcium imbalances observed in heart failure. In the present study, we used a transgenic mouse with an increased number of L-type calcium channels to identify the role of an increased, sustained ingress of calcium as an initiator of hypertrophy. METHODS AND RESULTS: Whole-heart histology and electrophysiology in isolated cardiomyocytes identified calcium-channel overexpression in the hearts of transgenic mice. Calcium-channel density was increased in 2-, 4-, and 8-month-old transgenic cardiomyocytes. Ventricular fibrosis, damage, and remodeling became more pronounced as the transgenic mice aged. Apoptosis was also present in transgenic hearts at 8 months of age. Increased protein kinase Calpha activation was elevated before the development of hypertrophy and failure. CONCLUSIONS: Transgenic mice developed hypertrophy and severe cardiomyopathy as a function of age, thus confirming that changes in channel density are sufficient to induce disease. The small, sustained increase in the ingress of Ca(2+) through the calcium channel elevated protein kinase Calpha before the development of hypertrophy, suggesting that protein kinase Calpha plays an important role in triggering hypertrophy.

Cell-specificity and signaling pathway of endothelin-1 gene regulation by hypoxia.

OBJECTIVES: Endothelin-1 (ET-1) is a potent vasoconstrictor that is expressed in endothelial cells and in many other cells and tissues. Increased plasma levels of the peptide have been associated with ischemic heart disease, atherosclerosis, and myocardial infarction. The objectives of the current study were (1) to determine the tissue specificity for induction of the ET-1 gene by hypoxia, (2) to determine whether the hypoxia regulatory pathway is the same as that in other hypoxia regulated genes and (3) to analyze the contributions of protein kinases for basal and induced expression of ET-1. METHODS: ET-1 transcript levels were measured by Northern blot and quantitative polymerase chain reaction in endothelial and non-endothelial cells following exposure to hypoxia. Regulatory steps within the pathway were identified by treating aerobic or hypoxic cultures with cycloheximide, PMA, a series of selective protein kinase inhibitors, and transition metals. The effects on ET-1 transcripts were compared with the ubiquitous hypoxia inducible pyruvate kinase gene. RESULTS: The induction of ET-1 by hypoxia in vitro occurred exclusively in early passage endothelial cells. This induction was prevented by treatment with the protein synthesis inhibitor cycloheximide and was at least partially mimicked by treatment with transition metals. Induction by hypoxia was not effected by inhibitors of protein kinase C, protein kinase A, calcium-calmodulin dependent protein kinase, or cyclic GMP dependent protein kinase. The basal expression was decreased and hypoxic induction was eliminated by treating cells with tyrosine kinase-selective inhibitors. CONCLUSIONS: Et-1 induction by hypoxia requires endothelial cell-specific factor(s) or steps, new protein synthesis, and may involve a haeme protein-containing pathway in oxygen sensing. A protein tyrosine kinase step is implicated for both basal and induced expression of the ET-1 gene.

Native-type DHP-sensitive calcium channel currents are produced by cloned rat aortic smooth muscle and cardiac alpha 1 subunits expressed in Xenopus laevis oocytes and are regulated by alpha 2- and beta-subunits.

Native tissue-like L-type voltage-dependent calcium channels (L-VDCC's) were expressed by in vitro transcribed cRNA injection of rat aorta or rabbit cardiac alpha 1 subunit into Xenopus laevis oocytes. Co-injection of VSM-alpha 1 with the cloned skeletal muscle beta-subunit (SK-beta) of the L-type VDCC significantly increased the expressed peak current amplitude without significant changes in kinetics. Similar results were obtained by co-injection of cardiac alpha 1 (DSHT-alpha 1) the cloned skeletal alpha 2-subunit (SK-alpha 2) or with SK-beta. The oocytes co-expressing cRNA's retained L-type VDCC pharmacology.

New antiarrhythmic agents. 2,2,5,5-Tetramethyl-3-pyrroline-3-carboxamides and 2,2,5,5-tetramethylpyrrolidine-3-carboxamindes.

N-(omega-Aminoalkyl)-2,2,5,5-tetramethyl-3-pyrroline- or -pyrrolidine-3-carboxamides were acylated on the primary amino group of the side chain by means of reactive acid derivatives (acid chlorides, activated esters, phthalic anhydrides, phthalimide, 2-alkyl-4H-3,1-benzoxazin-4-ones) or they were alkylated by forming the Schiff bases and subsequent sodium borohydride reduction. Other tetramethyl-3-pyrrolinecarboxamide compounds were synthesized by acylating the aminoalkyl compounds with 2,2,6,6-tetramethyl-3,5-dibromo-4-piperidinone in a reaction involving Favorskii rearrangement. Saturation of the double bond of some pyrroline derivatives furnished the pyrrolidinecarboxamides. The new compounds of each type were active against aconitine-induced arrhythmia and several of them had higher activity and better chemotherapeutic index than quinidine. A few selected examples from each type of the active new compounds showed strong activity against ouabain-induced arrhythmia; for comparison known drugs such as lidocaine, mexiletine, and tocainide were selected. The most potent compounds were oxidized to the paramagnetic nitroxides and the latter were reduced to the N-hydroxy derivatives; these products had no or only decreased antiarrhythmic effect.

Differential modulation of the GYKI 53784-induced inhibition of AMPA currents by various AMPA-positive modulators in cerebellar Purkinje cells.

The effects of various (S)-alpha-amino-3-hydroxy-5-methyl-4-izoxazole-propionate (AMPA) receptor modulators on AMPA-induced whole-cell currents were compared in isolated rat cerebellar Purkinje cells. The positive modulators, aniracetam, cyclothiazide, 1-(1, 3-benzodioxol-5-ylcarbonyl)-piperidine (1-BCP), and 1-(quinoxaline-6-ylcarbonyl)-piperidine (BDP-12), dose-dependently potentiated the steady-state component of AMPA currents. The negative modulator, (-)1-(4-aminophenyl)-4-methyl-7, 8-methylenedioxy-4,5-dihydro-3-methylcarbamoyl-2,3-benzodiazepine (GYKI 53784), dose-dependently suppressed AMPA responses. Its concentration-response curve was shifted to the right in a parallel fashion by all positive modulators, indicating a competitive type of interaction. However, the relative potencies of the positive modulators were different with regard to the enhancement of AMPA responses and the reversal of GYKI 53784-induced inhibition, respectively. It is supposed that positive modulators act at multiple allosteric sites and that they interact with GYKI 53784 at only one of these sites.

CGRP and adrenomedullin receptor populations in human cerebral arteries: in vitro pharmacological and molecular investigations in different artery sizes.

The aim of the present study was to determine functional and molecular characteristics of receptors for calcitonin gene-related peptide (CGRP) and adrenomedullin in three different diameter groups of lenticulostriate arteries. Furthermore, the presence of perivascular neuronal sources of CGRP was evaluated in these arteries. In the functional studies, in vitro pharmacological experiments demonstrated that both CGRP and adrenomedullin induce alpha-CGRP-(8-37) sensitive vasodilation in artery segments of various diameters. The maximal amounts of vasodilation induced by CGRP and adrenomedullin were not different, whereas the potency of CGRP exceeded that of adrenomedullin by 2 orders of magnitude. Significant negative correlations between artery diameters and maximal responses were demonstrated for CGRP and adrenomedullin. In addition, the potency of both peptides tended to increase in decreasing artery diameter. In the molecular experiments, levels of mRNAs encoding CGRP receptors and receptor subunits were compared using reverse transcriptase polymerase chain reactions (RT-PCR). The larger the artery, the more mRNA encoding receptor activity-modifying proteins 1 and 2 (RAMP1 and RAMP2) was detected relative to the amount of mRNA encoding the calcitonin receptor-like receptor. By immunohistochemistry, perivascular CGRP containing nerve fibres were demonstrated in all the investigated artery sizes. In conclusion, both CGRP and adrenomedullin induced vasodilation via CGRP receptors in human lenticulostriate artery of various diameter. The artery responsiveness to the CGRP receptor agonists increased with smaller artery diameter, whereas the receptor-phenotype determining mRNA ratios tended to decrease. No evidence for CGRP and adrenomedullin receptor heterogeneity was present in lenticulostriate arteries of different diameters.

The human superior cervical ganglion: neuropeptides and peptide receptors.

Noradrenaline (NA)- and neuropeptide Y (NPY)-containing cell bodies were found to occur in high numbers (>75% of all cells were positive) in the human superior cervical ganglion and distributed homogeneously throughout the ganglion and showed colocalisation. A few cell bodies were VIP-immunoreactive (-ir) (less than 5%) but none of them showed NOS-, CGRP- or SP-ir. Receptor mRNA expression was studied with RT-PCR. Total RNA from the superior cervical ganglion was successfully extracted. By using appropriate sense and antisense oligonucleotides designed from the published human sequences, we could show the presence of mRNA for the human NPY Y1, NPY Y2 and VPAC1 receptors but not CGRP1 receptor mRNA.

Signet-ring cell ependymoma: case report with implications for pathogenesis and differential diagnosis.

We describe light microscopic, immunohistochemical and ultrastructural features of a signet-ring cell ependymoma (WHO grade II) identified in a surgically resected left cerebellar cystic tumor from a 64-year-old man. Part of the tumor showed clear-cell differentiation. Immunohistochemical coexpression of glial fibrillary acidic protein and epithelial membrane antigen, characteristic of ependymoma, was detected in both components. Sinuous intermediate junctions, cytoplasmic lumina, and scant astroglial filaments were demonstrated by electron microscopy. Signet-ring cell change was shown to be induced by disproportionate cavitation of either microvillus-bearing cytoplasmic lumina or microrosettes. The staining qualities of clear cells were mainly due to paucity and degeneration of subcellular organelles. Therefore, signet-ring cell ependymomas represent a unique anomaly of intra- and extracellular compartmentalization to be distinguished from various unrelated forms of cytoplasmic volume increase, resulting in an optically similar "empty" appearance of tumor cells. As a clinically relevant consequence, signet-ring cell ependymoma must be included in the differential diagnosis of primary or metastatic neoplasms of the central nervous system, having in common a phenotype characterized by overdeveloped optically lucent cell bodies.

The ionic product of water in concentrated tetramethylammonium chloride solutions.

The ionic product of water, pK(w) = - log[H(+)][OH(-)] has been determined in aqueous solutions of tetramethylammonium chloride over the concentration range of 0.1-5.5 M at 25 degrees C using high-precision glass electrode potentiometric titrations. pK(w) data relating to aqueous potassium and sodium chlorides at ionic strengths up to 5 M are markedly lower than the tetramethylammonium chloride results. These differences are almost certainly due to weak associations between potassium and (especially) sodium and hydroxide ions.

Vein of Galen malformation combined with atrial septal defect in a neonate.

An arteriovenous fistula (AVF) is an abnormal connection between an artery and a vein, whereby the interconnecting capillary network is missing. Such a malformation frequently occurs in the deep midline regions of the brain, and the subsequent increased flow into the draining vein of Galen substantially dilates in an aneurysmal manner. Congenital forms of the aneurysmal dilatation of the vein of Galen (AVG) often lead to death in the neonatal period, predominantly due to cardiac failure caused by the increased venous inflow as a consequence of the intracerebral arteriovenous shunting. In the presented case a male baby suffered from a rare combination of a cerebral AVF and an atrial septal defect (ASD). He was born at week 38 of pregnancy and subsequently developed tachydyspnoe. Ultrasound (US) and CT scans revealed a large bilateral AVF with dilated basal venous sinuses, hydrocephalus and brain atrophy. In the heart, severe right ventricular hypertrophy, patent ductus arteriosus and an ASD were detectable by US. Neurosurgical consultation rejected the possibility of an operative treatment due to size and localization of the lesion and the existing irreversible brain damage. The child died because of cardiac failure 6 days after birth. Autopsy examination in the brain demonstrated a large conglomerate of dilated blood vessels predominantly in the midline and left occipital lobe, edema and hydrocephalus. In the heart, the ASD detected by US proved to be an ostium secundum-type lesion. Histologically, the conglomerate of vessels revealed features of an AVF and matched the characteristics of AVG. Consequences of chronic ischemic brain injury were also present, with ferruginated neurons suggesting intrauterine damage caused by a congenital AVF. Based on data in the literature, we assume that the left-to-right shunt due to increased venous influx into the heart caused not only cardiomegaly, but may have also interfered with the normal development of the atrial septum leading to an ASD, contributing to the rapid progression of the cardiac failure.

Antiarrhythmic effect of desethylamiodarone in conscious rats.

The effect of desethylamiodarone, a metabolite of amiodarone, was studied in the early phase of arrhythmias induced by coronary artery ligation in conscious rats. Desethylamiodarone pretreatment improved survival without altering the occurrence of different types of arrhythmias during the first 20 min after coronary ligation. It was concluded that desethylamiodarone may contribute to the antiarrhythmic effect seen after chronic amiodarone treatment.