The distinctive movement disorder of ovarian teratoma-associated encephalitis

The movement disorder observed in four cases of ovarian teratoma associated encephalitis is described. The illness began with neuropsychiatric symptoms and was followed by prolonged unresponsiveness, respiratory failure, and autonomic instability. The movement disorder consisted of semirhythmic repetitive bulbar and limb movements and persisted during prolonged periods of unresponsiveness, diminishing as awareness returned. The characteristics of the movement disorder differed from recognized dyskinesias. It is suggested that interruption of forebrain corticostriatal inputs by anti-N-methyl-D-aspartate (NMDA) receptor antibodies removes tonic inhibition of brainstem pattern generators releasing primitive patterns of bulbar and limb movement. Recognition of the distinctive movements should prompt a search for an ovarian teratoma since the condition is responsive to tumor resection and immunomodulation.

Cellular glutathione peroxidase in human brain: cellular distribution, and its potential role in the degradation of Lewy bodies in Parkinson's disease and dementia with Lewy bodies

Glutathione peroxidase (GPx-1) is regarded as one of the mammalian cell's main antioxidant enzymes inactivating hydrogen peroxide and protecting against oxidative stress. Using control, Parkinson's disease (PD), and dementia with Lewy bodies tissue (DLB) we have shown that GPx-1 is a 21-kD protein under reducing conditions in all tissues examined but is not in high abundance in human brain. Using immunohistochemistry we have mapped the cellular distribution of GPx-1 and have shown it to be in highest levels in microglia and with lower levels in neurons. Only a trace amount was detectable in astrocytes using immunofluorescence and GPx-1 was not detectable in oligodendrocytes. GPx-1 positive microglia were hypertrophied and more abundant in PD and DLB tissues and were seen to be making multiple contacts with neurons. In some cases neurons containing Lewy bodies were surrounded by microglia. Unstructured Lewy bodies were enveloped with a layer of GPx-1 that was partially colocalized with alpha-synuclein whereas concentric Lewy bodies had discrete deposits of GPx-1 around the periphery which appeared to be involved in the degradation of the Lewy bodies. These results suggest that abnormal alpha-synuclein as found in Lewy bodies produce hydrogen peroxide and these neurons are capable of directing antioxidant enzymes to regions of oxidative stress. These results also suggest that GPx-1 positive microglia are involved in neuroprotection in PD and DLB and that GPx-1 is an important antioxidant enzyme in neuronal defences.

NSF, Unc-18-1, dynamin-1 and HSP90 are inclusion body components in neuronal intranuclear inclusion disease identified by anti-SUMO-1-immunocapture

Neuronal intranuclear inclusion disease, a progressive ataxia that may be familial or sporadic, is characterized by numerous neuronal intranuclear inclusion bodies similar to those found in polyglutamine repeat diseases. Previously, we found that the intranuclear inclusion bodies are intensely immunopositive for SUMO-1, a protein which covalently conjugates to other proteins in a similar way to ubiquitin. To identify the SUMO-1-associated proteins in the inclusion bodies, we isolated intranuclear inclusion bodies from fresh, frozen brain tissue of a case with familial neuronal intranuclear inclusion disease and solubilized the proteins. SUMO-1-associated inclusion body proteins were then immunocaptured using an anti-SUMO-1 antibody. The proteins, NSF, dynamin-1 and Unc-18-1 (rbSEC1), involved in membrane trafficking of proteins, and the chaperone HSP90, were identified following anti-SUMO-1-immunocapture by using tandem mass spectrometry and database searching. Immunohistochemistry of brain sections and crude brain homogenates of three cases of familial neuronal intranuclear inclusion disease confirmed the presence of these proteins in intranuclear inclusions.

Aquaporin-4 in acute cerebral edema produced by Clostridium perfringens type D epsilon toxin

Sheep, particularly lambs, with high circulating levels of Clostridium perfringens type D epsilon toxin develop severe neurologic signs and often die suddenly. On microscopic examination, in the brain, there is microvascular endothelial injury and diffuse vasogenic edema. The aquaporin (AQP) family of membrane water-channel proteins, especially AQP-4, is important in the regulation of water balance in the brain and facilitates reabsorption of excess fluid. In rats given epsilon toxin, generalized cerebral edema was demonstrated by marked albumin extravasation and was correlated with widespread upregulation of AQP-4 in astrocytes. These results suggest that AQP-4 has a role in the clearance of edema fluid from brains damaged by this clostridial toxin.

The 'rosette-forming glioneuronal tumor' of the fourth ventricle

Tumors containing both neuronal and glial components are a rare heterogeneous group with unique features that require further subclassification. The rosette-forming glioneuronal tumor of the fourth ventricle is one of a number of recently described glioneuronal tumors, which has been accorded official WHO nosologic status only in 2007. We describe the clinical and pathologic features of two patients with rare rosette-forming glioneuronal tumors of the fourth ventricle, one of which was associated with dysgenetic tricho-rhinopharyngeal type I syndrome.

Peroxiredoxin 6 in human brain: molecular forms, cellular distribution and association with Alzheimer's disease pathology

Peroxiredoxin 6 is an antioxidant enzyme and is the 1-cys member of the peroxiredoxin family. Using two-dimensional electrophoresis and Western blotting, we have shown for the first time that, in human control and brain tissue of patient’s with Alzheimer’s disease (AD), this enzyme exists as three major and five minor forms with pIs from 5.3 to 6.1. Using specific cellular markers, we have shown that peroxiredoxin 6 is present in astrocytes with very low levels in neurons, but not detectable in microglia or oligodendrocytes. In control brains, there was a very low level of peroxiredoxin 6 staining in astrocytes that was confined to a “halo” around the nucleus. In AD, there were marked increases in the number and staining intensity of peroxiredoxin 6 positive astrocytes in both gray and white matter in the midfrontal cortex, cingulate, hippocampus and amygdala. Confocal microscopy using antibodies to Aβ peptide, tau and peroxiredoxin 6 showed that peroxiredoxin 6 positive astrocytes are closely involved with diffuse plaques and to a lesser extent with neuritic plaques, suggesting that plaques are producing reactive oxygen species. There appeared to be little astrocytic response to tau containing neurons. Although peroxiredoxin 6 positive astrocytes were seen to make multiple contacts with tau positive neurons, there was no intraneuronal colocalization. In brain tissue of patients with AD, many blood vessels exhibited peroxiredoxin 6 staining that appeared to be due to the astrocytic foot processes. These results suggest that oxidative stress conditions exist in AD and that peroxiredoxin 6 is an important antioxidant enzyme in human brain defenses.

p25alpha relocalizes in oligodendroglia from myelin to cytoplasmic inclusions in multiple system atrophy

p25alpha is an oligodendroglial protein that can induce aggregation of alpha-synuclein and accumulates in oligodendroglial cell bodies containing fibrillized alpha-synuclein in the neurodegenerative disease multiple system atrophy (MSA). We demonstrate biochemically that p25alpha is a constituent of myelin and a high-affinity ligand for myelin basic protein (MBP), and in situ immunohistochemistry revealed that MBP and p25alpha colocalize in myelin in normal human brains. Analysis of MSA cases reveals dramatic changes in p25alpha and MBP throughout the course of the disease. In situ immunohistochemistry revealed a cellular redistribution of p25alpha immunoreactivity from the myelin to the oligodendroglial cell soma, with no overall change in p25alpha protein concentration using immunoblotting. Concomitantly, an approximately 80% reduction in the concentration of full-length MBP protein was revealed by immunoblotting along with the presence of immunoreactivity for MBP degradation products in oligodendroglia. The oligodendroglial cell bodies in MSA displayed an enlargement along with the relocalization of p25alpha, and this was enhanced after the deposition of alpha-synuclein in the glial cytoplasmic inclusions. Overall, the data indicate that changes in the cellular interactions between MBP and p25alpha occur early in MSA and contribute to abnormalities in myelin and subsequent alpha-synuclein aggregation and the ensuing neuronal degeneration that characterizes this disease.

Novel fibroblastic onion bulbs in a demyelinating avian peripheral neuropathy produced by riboflavin deficiency

The finding of novel fibroblastic onion bulb-like structures in peripheral nerves is reported for the first time in avian riboflavin deficiency. Day old broiler meat chickens were fed a riboflavin deficient diet (1.8 mg/kg) and were killed on postnatal days 6, 11, 16, 21 and 31, whereas control chickens were fed a conventional diet containing 5.0 mg/kg riboflavin. The fibroblastic onion bulb-like structures were found in sciatic and brachial nerves from day 11 onwards and consisted of long cytoplasmic processes of hypertrophied fibroblasts surrounding demyelinated, remyelinated and normally myelinated axons. The fibroblast cytoplasmic processes often enveloped more than one nerve fibre to produce a unique compound-like onion bulb structure. These onion bulb-like structures occurred early in the course of segmental demyelination at the same time as tomacula formation and became increasingly more prominent in the later stages of demyelination and remyelination. The molecular basis of formation of these unique structures requires further study as to the basis of the attraction of the fibroblast processes to nerve fibres associated with myelinating Schwann cells. The model may also be useful in investigating the role of endoneurial fibroblasts in endoneurial fibrosis as the early fibroblastic response in the onion bulbs is distinct from the more usual fibroblastic deposition of collagen in end-stage peripheral nerve disease.

Effect of mobile telephony on blood-brain barrier permeability in the fetal mouse brain

AIMS

To study the effect of mobile telephone exposure on blood-brain barrier (BBB) permeability in the immature brain.

METHODS

Using a purpose-designed exposure system at 900 MHz, pregnant mice were given a single, far-field, whole body exposure at a specific absorption rate of 4 W/kg for 60 min/day from day 1 to day 19 of gestation. Pregnant control mice were sham-exposed or freely mobile in a cage without further restraint and a positive control group with cadmium-induced BBB damage was also included. Immediately prior to parturition on gestational day 19, fetal heads were collected, fixed in Bouin's fixative and paraffin embedded. Disruption of BBB integrity was detected immunohistochemically using endogenous albumin as a vascular tracer in cerebral cortex, thalamus, basal ganglia, hippocampus, cerebellum, midbrain and medulla.

RESULTS

No albumin extravasation was found in exposed or control brains.

CONCLUSION

In this animal model, whole of gestation exposure to global system for mobile communication-like radiofrequency fields did not produce any increase in vascular permeability in the fetal brain regions studied using endogenous albumin as a light microscopic immunohistochemical marker.

Expression of the immediate early gene, c-fos, in fetal brain after whole of gestation exposure of pregnant mice to global system for mobile communication microwaves

AIMS

To study immediate early gene, c-fos, expression as a marker of neural stress after whole of gestation exposure of the fetal mouse brain to mobile telephone-type radiofrequency fields.

METHODS

Using a purpose-designed exposure system at 900 MHz, pregnant mice were given a single, far-field, whole body exposure at a specific absorption rate of 4 W/kg for 60 min/day from day 1 to day 19 of gestation. Pregnant control mice were sham-exposed or freely mobile in a cage without further restraint. Immediately prior to parturition on gestational day 19, fetal heads were collected, fixed in 4% paraformaldehyde and paraffin embedded. Any stress response in the brain was detected by c-fos immunohistochemistry in the cerebral cortex, basal ganglia, thalamus, hippocampus, midbrain, cerebellum and medulla.

RESULTS

c-fos expression was of limited, but consistent, neuroanatomical distribution and there was no difference in immunoreactivity between exposed and control brains.

CONCLUSION

In this animal model, no stress response was detected in the fetal brain using c-fos immunohistochemistry after whole of gestation exposure to mobile telephony.

Increased substance P immunoreactivity and edema formation following reversible ischemic stroke

Previous results from our laboratory have shown that neurogenic inflammation is associated with edema formation after traumatic brain injury (TBI). This neurogenic inflammation was characterized by increased substance P (SP) immunoreactivity and could be attenuated with administration of SP antagonists with a resultant decrease in edema formation. Few studies have examined whether neurogenic inflammation, as identified by increased SP immunoreactivity, occurs after stroke and its potential role in edema formation. The present study examines SP immunoreactivity and edema formation following stroke. Experimental stroke was induced in halothane anaesthetized male Sprague-Dawley rats using a reversible thread model of middle cerebral artery occlusion. Increased SP immunoreactivity at 24 hours relative to the non-infarcted hemisphere was observed in perivascular, neuronal, and glial tissue, and within the penumbra of the infarcted hemisphere. It was not as apparent in the infarct core. This increased SP immunoreactivity was associated with edema formation. We conclude that neurogenic inflammation, as reflected by increased SP immunoreactivity, occurs following experimental stroke, and that this may be associated with edema formation. As such, inhibition of neurogenic inflammation may represent a novel therapeutic target for the treatment of edema following reversible, ischemic stroke.

Soluble amyloid precursor protein α reduces neuronal injury and improves functional outcome following diffuse traumatic brain injury in rats

Amyloid precursor protein (APP) has previously been shown to increase following traumatic brain injury (TBI). Whereas a number of investigators assume that increased APP may lead to the production of neurotoxic Abeta and be deleterious to outcome, the soluble alpha form of APP (sAPPalpha) is a product of the non-amyloidogenic cleavage of amyloid precursor protein that has previously been shown in vitro to have many neuroprotective and neurotrophic functions. However, no study to date has addressed whether sAPPalpha may be neuroprotective in vivo. The present study examined the effects of in vivo, posttraumatic sAPPalpha administration on functional motor outcome, cellular apoptosis, and axonal injury following severe impact-acceleration TBI in rats. Intracerebroventricular administration of sAPPalpha at 30 min posttrauma significantly improved motor outcome compared to vehicle-treated controls as assessed using the rotarod task. Immunohistochemical analysis using antibodies directed toward caspase-3 showed that posttraumatic treatment with sAPPalpha significantly reduced the number of apoptotic neuronal perikarya within the hippocampal CA3 region and within the cortex 3 days after injury compared to vehicle-treated animals. Similarly, sAPPalpha-treated animals demonstrated a reduction in axonal injury within the corpus callosum at all time points, with the reduction being significant at both 3 and 7 days postinjury. Our results demonstrate that in vivo administration of sAPPalpha improves functional outcome and reduces neuronal cell loss and axonal injury following severe diffuse TBI in rats. Promotion of APP processing toward sAPPalpha may thus be a novel therapeutic strategy in the treatment of TBI.

Paranodal pathology in Tangier disease with remitting-relapsing multifocal neuropathy

Pathological studies of a sural nerve biopsy in a man with Tangier disease presenting as a remitting-relapsing multifocal neuropathy showed abnormalities in the paranodal regions, including lipid deposition (65%) and redundant myelin foldings, with various degrees of myelin splitting and vesiculation (43%) forming small tomacula and abnormal myelin terminal loops (4%). The internodal regions were normal in the majority of myelinated fibres. Abnormal lipid storage was also present in the Schwann cells of the majority of unmyelinated fibres (67%). The evidence suggests that the noncompacted myelin region of the paranode is a preferential site for lipid storage in the myelinated Schwann cell, and that the space-occupying effects of the cholesterol esters leads to paranodal malfunction and tomacula formation as the pathological basis for the multifocal relapsing-remitting clinical course.

Early paranodal myelin swellings (tomacula) in an avian riboflavin deficiency model of demyelinating neuropathy

INTRODUCTION

Disruption of the complex architectural and molecular organization of the paranodal region of myelinated peripheral nerve fiber may initiate the evolving time dependent process of segmental demyelination. In support of this notion was the finding of focal paranodal myelin swellings (tomacula) due to redundant folding of myelin sheaths, early in the time course of an avian riboflavin deficiency model of demyelinating neuropathy.

METHODS

Newborn broiler meat chickens were maintained either on a routine diet containing 5.0 mg/kg riboflavin (control group) or a riboflavin-deficient diet containing 1.8 mg/kg riboflavin. Riboflavin concentrations in the liver were measured at postnatal day 11. Peripheral nerves were morphologically examined at days 6, 11, 16 and 21 using light and electron microscopy and teased nerve fiber techniques.

RESULTS

Riboflavin-deficient chickens showed signs of a neuropathy from days 8 and pathological examination of peripheral nerves revealed a demyelinating neuropathy with paranodal tomacula formation starting on day 11. Paranodal tomacula consisted of redundant myelin infoldings or outfoldings, increased in size and frequency after day 11. After day 16, the paranodal swellings showed prominent degenerative changes accompanied by an increased frequency of myelinated fibers showing demyelination.

CONCLUSION

Tomacula due to redundant myelin folds are generally considered a remyelination phenomenon, yet in this avian riboflavin deficiency model of demyelination, the paranodal tomacula occurred early in the course of demyelination.

A Western Australian kindred with Dutch cerebral amyloid angiopathy

A family from the south of Western Australia is described with Dutch cerebral amyloid angiopathy (HCHWA-D). The proband died at age 60 from recurrent lobar haemorrhages in the brain, as did his sister and five other family members. The APP 693 mutation at position 22 of the Abetapeptide resulting in a glutamine for glutamic acid was identified in the proband and the affected sister. Pathologically lobar haemorrhages were found with cerebrovascular angiopathy; neuritic plaques were found but no neurofibrilary tangles. There was a leukoencephalopathy on MRI scanning. Dementia and cognitive decline has not been observed in this family. This is the first family reported outside of Europe and the Northern Hemisphere. The discovery highlights the importance of detecting this rare cause of fatal cerebral haemorrhage as it has implications for gene testing and general medical management.

Immunohistochemical Staining of Epoxy Resin Sections of Peripheral Nerve

The authors describe a simple and cost-effective method of immunostaining semithin epoxy resin sections of peripheral nerve for light microscopy with antibodies to myelin protein zero, peripheral myelin protein 22, myelin basic protein, and neurofilament protein 200 using a combined technique of surface etching with sodium ethoxide and heat-induced antigen retrieval.

A case of presumptive primary lateral sclerosis with upper and lower motor neurone pathology

Motor Neurone Disease (MND) is one of the commonest neurodegenerative disorders of adulthood. MND characteristically presents with a combination of both upper and lower motor neurone features. Primary Lateral Sclerosis (PLS) is thought to be a variant of MND presenting with purely upper motor neurone signs. Debate continues over whether PLS constitutes a distinct pathological entity or whether it is part of the spectrum of motor neurone diseases that present as an upper motor neurone-predominant form of MND. We present a case of MND with purely upper motor neurone features and a prominent pain component. A pre-mortem diagnosis of PLS was made, however autopsy findings demonstrated both upper and lower motor neurone involvement. We believe these findings support the view that PLS is not a discrete pathological entity, but that it is a part of the range of motor neurone diseases that present with predominant but not exclusive upper motor neurone involvement. This case also highlights the feature that pain may be associated with MND even though it is not appreciated to have a sensory pathology.

Downregulation of amyloid precursor protein (APP) expression following post-traumatic cyclosporin-A administration

The aim of these studies was to assess and quantitate the effects of cyclosporin-A (CyA) on brain APP messenger RNA and neuronal perikaryal APP antigen expression following controlled focal head impact in sheep. Impact results in a significant increase in both APP mRNA and neuronal perikaryal APP antigen expression. Post-traumatic administration of CyA (intrathecal 10 mg/kg) resulted in a reduction in APP mRNA and neuronal perikaryal antigen expression. At 2 h postinjury, CyA treatment caused a statistically significant (p < 0.05) 1.3 +/- 0.1-fold decrease in APP mRNA in the central gray matter of impacted sheep compared to untreated impacted sheep. A more profound reduction in APP mRNA synthesis (1.6 +/- 0.2 fold) was evident at 6 h (p < 0.05). The mean percentage brain area with APP immunoreactive neuronal perikarya at 6 h post-injury was 94.5% in untreated impacted animals, 10.0% in CyA-treated impacted animals, 5.5% in untreated nonimpacted animals, and 6% in CyA-treated non-impacted controls. These results demonstrate that CyA has a downregulatory effect on increased APP expression caused by TBI.