Creutzfeldt-Jakob disease. The neuropathology of a transmission experiment

Extracellular vesicles with diagnostic and therapeutic potential for prion diseases

Prion diseases (PrD) or transmissible spongiform encephalopathies (TSE) are invariably fatal and pathogenic neurodegenerative disorders caused by the self-propagated misfolding of cellular prion protein (PrP^C) to the neurotoxic pathogenic form (PrP^TSE) via a yet undefined but profoundly complex mechanism. Despite several decades of research on PrD, the basic understanding of where and how PrP^C is transformed to the misfolded, aggregation-prone and pathogenic PrP^TSE remains elusive. The primary clinical hallmarks of PrD include vacuolation-associated spongiform changes and PrP^TSE accumulation in neural tissue together with astrogliosis. The difficulty in unravelling the disease mechanisms has been related to the rare occurrence and long incubation period (over decades) followed by a very short clinical phase (few months). Additional challenge in unravelling the disease is implicated to the unique nature of the agent, its complexity and strain diversity, resulting in the heterogeneity of the clinical manifestations and potentially diverse disease mechanisms. Recent advances in tissue isolation and processing techniques have identified novel means of intercellular communication through extracellular vesicles (EVs) that contribute to PrP^TSE transmission in PrD. This review will comprehensively discuss PrP^TSE transmission and neurotoxicity, focusing on the role of EVs in disease progression, biomarker discovery and potential therapeutic agents for the treatment of PrD.

Methionine oxidation within the prion protein

Prion diseases are characterized by the self-templated misfolding of the cellular prion protein (PrPC) into infectious aggregates (PrPSc). The detailed molecular basis of the misfolding and aggregation of PrPC remains incompletely understood. It is believed that the transient misfolding of PrPC into partially structured intermediates precedes the formation of insoluble protein aggregates and is a critical component of the prion misfolding pathway. A number of environmental factors have been shown to induce the destabilization of PrPC and promote its initial misfolding. Recently, oxidative stress and reactive oxygen species (ROS) have emerged as one possible mechanism by which the destabilization of PrPC can be induced under physiological conditions. Methionine residues are uniquely vulnerable to oxidation by ROS and the formation of methionine sulfoxides leads to the misfolding and subsequent aggregation of PrPC. Here, we provide a review of the evidence for the oxidation of methionine residues in PrPC and its potential role in the formation of pathogenic prion aggregates.

MS and infections-Abandoned and surviving hypotheses

In this introduction, we follow the ups and downs of infections in MS pathogenesis. Our arguments focus on specific agents and events, not referring to general MS epidemiology. The historical approach continues on to contemporary data and a critical analysis.

A brief history of prions

Proteins were described as distinct biological molecules and their significance in cellular processes was recognized as early as the 18th century. At the same time, Spanish shepherds observed a disease that compelled their Merino sheep to pathologically scrape against fences, a defining clinical sign that led to the disease being named scrapie. In the late 19th century, Robert Koch published his postulates for defining causative agents of disease. In the early 20th century, pathologists Creutzfeldt and Jakob described a neurodegenerative disease that would later be included with scrapie into a group of diseases known as transmissible spongiform encephalopathies (TSEs). Later that century, mounting evidence compelled a handful of scientists to betray the prevailing biological dogma governing pathogen replication that Watson and Crick so convincingly explained by cracking the genetic code just two decades earlier. Because TSEs seemed to defy these new rules, J.S. Griffith theorized mechanisms by which a pathogenic protein could encipher its own replication blueprint without a genetic code. Stanley Prusiner called this proteinaceous infectious pathogen a prion. Here we offer a concise account of the discovery of prions, the causative agent of TSEs, in the wider context of protein biochemistry and infectious disease. We highlight the discovery of prions in yeast and discuss the implication of prions as epigenomic carriers of biological and pathological information. We also consider expanding the prion hypothesis to include other proteins whose alternate isoforms confer new biological or pathological properties.

Molecular pathogenesis of sporadic prion diseases in man

The yeast, fungal and mammalian prions determine heritable and infectious traits that are encoded in alternative conformations of proteins. They cause lethal sporadic, familial and infectious neurodegenerative conditions in man, including Creutzfeldt-Jakob disease (CJD), Gerstmann-Sträussler-Scheinker syndrome (GSS), kuru, sporadic fatal insomnia (SFI) and likely variable protease-sensitive prionopathy (VPSPr). The most prevalent of human prion diseases is sporadic (s)CJD. Recent advances in amplification and detection of prions led to considerable optimism that early and possibly preclinical diagnosis and therapy might become a reality. Although several drugs have already been tested in small numbers of sCJD patients, there is no clear evidence of any agent’s efficacy. Therefore, it remains crucial to determine the full spectrum of sCJD prion strains and the conformational features in the pathogenic human prion protein governing replication of sCJD prions. Research in this direction is essential for the rational development of diagnostic as well as therapeutic strategies. Moreover, there is growing recognition that fundamental processes involved in human prion propagation – intercellular induction of protein misfolding and seeded aggregation of misfolded host proteins – are of far wider significance. This insight leads to new avenues of research in the ever-widening spectrum of age-related human neurodegenerative diseases that are caused by protein misfolding and that pose a major challenge for healthcare.

Liposome-siRNA-peptide complexes cross the blood-brain barrier and significantly decrease PrP on neuronal cells and PrP in infected cell cultures

Background

Recent advances toward an effective therapy for prion diseases employ RNA interference to suppress PrP^C expression and subsequent prion neuropathology, exploiting the phenomenon that disease severity and progression correlate with host PrP^C expression levels. However, delivery of lentivirus encoding PrP shRNA has demonstrated only modest efficacy in vivo.

Methodology/Principal Findings

Here we describe a new siRNA delivery system incorporating a small peptide that binds siRNA and acetylcholine receptors (AchRs), acting as a molecular messenger for delivery to neurons, and cationic liposomes that protect siRNA-peptide complexes from serum degradation.

Conclusions/Significance

Liposome-siRNA-peptide complexes (LSPCs) delivered PrP siRNA specifically to AchR-expressing cells, suppressed PrP^C expression and eliminated PrP^RES formation in vitro. LSPCs injected intravenously into mice resisted serum degradation and delivered PrP siRNA throughout the brain to AchR and PrP^C-expressing neurons. These data promote LSPCs as effective vehicles for delivery of PrP and other siRNAs specifically to neurons to treat prion and other neuropathological diseases.

Transgenic mice expressing bovine PrP with a four extra repeat octapeptide insert mutation show a spontaneous, non-transmissible, neurodegenerative disease and an expedited course of BSE infection

Transgenic (Tg) mice carrying four extra octapeptide repeats (OR) in the bovine PrP gene (10OR instead of 6) have been generated. In these mice, neuropathological changes were observed depending upon the level of transgene expression. These changes primarily involved a slowly advancing neurological disorder, characterized clinically by ataxia, and neuropathologically, by vacuolization in different brain areas, gliosis, and loss of cerebellar granule cells. Accumulation of insoluble bovine 10OR-PrP (bo10OR-PrP) was observed depending on the level of expression but no infectivity was found associated with this insoluble form. We also compared the behavior of bo6OR-PrP and bo10OR-PrP Tg mouse lines in response to BSE infection. BSE-inoculated bo10ORTg mice showed an altered course of BSE infection, reflected by reduced incubation times when compared to bo6ORTg mice expressing similar levels of the wild type 6OR-PrP. In BSE-inoculated mice, it was possible to detect PrP(res) in 100% of the animals. While insoluble bo10OR-PrP from non-inoculated bo10ORTg mice was non-infectious, brain homogenates from BSE-inoculated bo10ORTg mice were highly infectious in all the Tg mouse lines tested. This Tg mouse model constitutes a new way of understanding the pathobiology of bovine transmissible spongiform encephalopathy. Its potential applications include the assessment of new therapies against prion diseases.

Different behavior toward bovine spongiform encephalopathy infection of bovine prion protein transgenic mice with one extra repeat octapeptide insert mutation

In humans, insert mutations within the repetitive octapeptide region of the prion protein gene (Prnp) are often associated with familial spongiform encephalopathies. In this study, transgenic mice expressing bovine PrP (boTg mice) bearing an additional octapeptide insertion to the wild type (seven octapeptide repeats instead of six) showed an altered course of bovine spongiform encephalopathy (BSE) infection, reflected as reduced incubation times when compared with boTg mice expressing similar levels of the wild-type six-octapeptide protein. In both boTg mouse lines (bo6ORTg and bo7ORTg), incubation times were affected drastically depending on transgene expression levels and the inoculum used. In accordance with the lack of an interspecies barrier to BSE infection, we detected the typical signs of CNS spongiform degeneration by histopathological analysis and the presence of the bovine prion PrP(res) by Western blot or immunohistochemical analyses. When 7OR-PrP(res) was propagated in bo7ORTg mice, a similar earlier onset of clinical signs was observed compared with bo6ORTg mice. Proteins PrP(C) and PrP(res) containing seven octapeptides (7OR-PrP(C) and 7OR-PrP(res)) showed similar protease sensitivity and insolubility in nondenaturing detergents to homologous 6OR-PrP(C) and 6OR-PrP(res). In addition, bo7ORTg mice showed a higher sensitivity than bo6ORTg mice for detecting prion infection in specimens previously diagnosed as negative by conventional biochemical techniques. In the absence of clinical signs of disease, 7OR-PrP(res) could be detected as early as 120 d after inoculation by immunohistochemical and Western blot analyses. These findings may help us improve the current mouse bioassays and understand the role of the octapeptide repeat region in susceptibility to disease.

Differential expression of cellular prion protein in mouse brain as detected with multiple anti-PrP monoclonal antibodies

The normal cellular prion protein (PrP(C)) plays an essential role in the development of prion diseases. Indirect evidence has suggested that different PrP(C) glycoforms may be expressed in different brain regions and perform distinct functions. However, due to a lack of monoclonal antibodies (Mabs) that are specific for mouse PrP(C), the expression of PrP(C) in the mouse brain has not been studied in great detail. We used Mabs specific for either the N-terminus or the C-terminus of the mouse PrP(C) to study its expression in the mouse brain by immunoblotting and immunohistochemistry. Immunoblotting studies demonstrated that the expression of PrP(C) differed quantitatively as well as qualitatively in different regions of the brain. The anti-C-terminus Mabs reacted with all three molecular weight bands of PrP(C); the anti-N-terminus Mabs only reacted with the 39-42 kDa PrP(C). The results from immunohistochemical staining revealed the spatial distribution of PrP(C) in the mouse brain, which were consistent with that from immunoblotting. Although expression of PrP(C) has been reported to be required for long-term survival of Purkinje cells, we were unable to detect PrP(C) in the Purkinje cell layer in the cerebellum with multiple anti-PrP Mabs. Our findings suggest that PrP(C) variants, i.e. various glycoforms and truncated forms, might be specifically expressed in different regions of mouse brain and might have different functions.

Astrocytosis and proliferating cell nuclear antigen expression in brains of scrapie-infected hamsters

Scrapie is a neurodegenerative disease in sheep and goats. Neuropathological examination shows astrocytosis. One issue is whether the astrocytosis seen in scrapie is a function of an increase in reactivity of individual cells, or whether there is actual replication of astrocytes. We used double-label immunohistochemistry for proliferating cell nuclear antigen (PCNA) and for glial fibrillary acidic protein (GFAP) to determine the mitotic state of cells and to confirm their identity as astrocytes. Brain sections from hamsters (strain LVG/LAK) infected with 139H or 263K scrapie isolates were examined. GFAP immunostaining was increased in astrocytes in most regions of the brains of scrapie-infected hamsters. These qualitative observations were confirmed by computerized image analysis quantification. A proportion of the hypertrophic astrocytes (0.5-10.8%, depending on specific location) were PCNA immunoreactive. The PCNA-immunopositive astrocytes were most frequently found in cerebral cortex, corpus callosum, subependymal areas, fimbria, caudate, thalamus, hypothalamus, hippocampus, and dentate gyrus. Our results suggest that the astrocytosis seen in scrapie-infected animals is, at least in part, owing to actual replication of astrocytes in these animals. We hypothesize that the astrocytes may be an important locus for the disease process.

Heightened expression of tumor necrosis factor alpha, interleukin 1 alpha, and glial fibrillary acidic protein in experimental Creutzfeldt-Jakob disease in mice

The ultrastructural pathology of myelinated axons in mice infected experimentally with the Fujisaki strain of Creutzfeldt-Jakob disease (CJD) virus is characterized by myelin sheath vacuolation that closely resembles that induced in murine spinal cord organotypic cultures by tumor necrosis factor alpha (TNF-alpha), a cytokine produced by astrocytes and macrophages. To clarify the role of TNF-alpha in experimental CJD, we investigated the expression of TNF-alpha in brain tissues from CJD virus-infected mice at weekly intervals after inoculation by reverse transcription-coupled PCR, Northern and Western blot analyses, and immunocytochemical staining. Neuropathological findings by electron microscopy, as well as expression of interleukin 1 alpha and glial fibrillary acidic protein, were concurrently monitored. As determined by reverse transcription-coupled PCR, the expression of TNF-alpha, interleukin 1 alpha, and glial fibrillary acidic protein was increased by approximately 200-fold in the brains of CJD virus-inoculated mice during the course of disease. By contrast, beta-actin expression remained unchanged. Progressively increased expression of TNF-alpha in CJD virus-infected brain tissues was verified by Northern and Western blot analyses, and astrocytes in areas with striking myelin sheath vacuolation were intensely stained with an antibody against murine TNF-alpha. The collective findings of TNF-alpha overexpression during the course of clinical disease suggest that TNF-alpha may mediate the myelin sheath vacuolation observed in experimental CJD.

Spongy state (status spongiosus) and inhibition of Na,K-ATPase: a pathogenetic theory

Spongiform encephalopathies are characterized above all by spongiosis. This neuropathological characteristic is morphologically mimed by in vivo inhibition of cerebral brain Na,K-ATPase by means of subdural administration of ouabain. In this paper we underline the possibility that the 'spongiotic state' in other diseases might also be caused by the inhibition of this enzyme, thus hypothesizing that it is the enzyme itself that is targeted by the infective agent. The infective agent could, we believe, be shown to be linked to the enzyme if it were separated from the infected brain.

Pathology of the transmissible spongiform encephalopathies with special emphasis on ultrastructure

The transmissible spongiform encephalopathies are a group of genetic and infectious disorders which are exemplified by scrapie in animals and Creutzfeldt-Jakob disease in humans. The spongiform encephalopathies are characterized by symmetrical vacuolation of neurons and neuropil. Amyloid plaque formation similar to that found in Alzheimer's disease is conspicuous in many, but not all, of these diseases. The sub-cellular pathology features of the spongiform encephalopathies have been studied by conventional transmission electron microscopy, scanning electron microscopy, freeze fracture, negative staining and most recently by application of immunogold labelling methods. Although these studies have revealed many unusual structures, convincing virus-like particles have not been demonstrated. Considerable data, including important transgenic mouse studies, now suggest that a single cellular protein, designated prion protein, is necessary for infection. Ultrastructural immunogold studies have shown that prion protein is released from the surface of neurons and neurites, diffuses through the extracellular space around infected cells where it accumulates and finally becomes aggregated as amyloid fibrils. It is likely that the accumulation of prion protein within the extracellular space is instrumental in causing nerve cell dysfunction and, ultimately, neurological disease.

Classification of the cerebral edemas with reference to hydrocephalus and pseudotumor cerebri

Cerebral edema is a common clinical disorder that results from an abnormal increase in water content within the extracellular (EC) compartment of the brain. It is distinguished from two other types of brain bulk enlargement: (1) vascular swelling, caused by arterial dilatation or venous obstruction; and (2) cellular swelling, caused by cytotoxic injuries or metabolic storage. Under normal conditions, the EC compartment has two fluids, the interstitial fluid (ISF) and the cerebrospinal fluid (CSF), and extends from the blood brain barrier (BBB) through a series of 100 to 150-A-wide intercellular spaces that are anatomically continuous with the CSF spaces. There are four primary types of EC edema: (1) vasogenic edema, which results from an increase in brain capillary permeability, the most common type, in which leakage of plasma constituents into the brain follows the pathways of ISF bulk flow and is governed by the interaction of systemic arterial pressure and tissue resistance; (2) osmotic edema, which results from an unfavorable osmotic gradient between the plasma and ISF across an intact BBB; (3) compressive edema, which results from obstruction of ISF bulk flow pathways; and (4) hydrocephalic edema, which results from obstruction of CSF bulk flow pathways. In this latter type of edema, distension of the collecting channels proximal to the block leads to retrograde flooding of the EC compartment with the formation of periventricular edema. The syndrome of pseudotumor cerebri includes several different types of brain bulk enlargement.

Ultrastructural pathology of axons and myelin in experimental scrapie in hamsters and bovine spongiform encephalopathy in cattle and a comparison with the panencephalopathic type of Creutzfeldt-Jakob disease

We report the ultrastructural pathology of axons and myelin sheaths in bovine spongiform encephalopathy (BSE) and experimental scrapie in hamsters and compare it with that found in a panencephalopathic model of Creutzfeldt-Jakob disease (CJD). Intramyelinic vacuoles (myelin ballooning), dystrophic axons, phagocytic astrocytes and macrophages were found in all three models but to different degrees, while axons containing numerous cellular processes and concentric cisterns were observed only in experimental scrapie and CJD. We conclude that axonal and myelin pathology is a widespread phenomenon and the differences between panencephalopathic CJD and polioencephalopathic BSE and scrapie are only quantitative.

From slow virus to prion: a review of transmissible spongiform encephalopathies

Spongiform encephalopathies include seven neurodegenerative diseases: three in man (Creutzfeldt-Jakob disease, Gerstmann-Sträussler-Scheinker disease and kuru) and four in animals (scrapie, mink encephalopathy, bovine spongiform encephalopathy and chronic wasting disease in deer and elks). They are all transmissible to a variety of species, and man-to-man propagation of the diseases in the form of iatrogenic transmission has been well-documented. The infectious agent is highly unusual and the pathogenesis of infection remains controversial. The term prion was introduced to describe the proteinaceous infectious agent. Purification of this agent yielded a unique sialoglycoprotein, associated with the neuronal cell membrane, which is all or part of the infectious agent. Molecular genetics revealed variations in the prion protein; these are linked to or associated with the inherited forms of spongiform encephalopathies: familial Creutzfeldt-Jakob disease and Gerstmann-Sträussler-Scheinker disease. The histological triad of spongiform change, neuronal loss and astrocytosis dominate the histological picture of spongiform encephalopathies. A recent case which did not develop any of the histological hallmarks of disease, but did have genetic abnormalities typical of the disease, indicates that the true incidence of Creutzfeldt-Jakob disease may be considerably higher than previously accepted, and a combination of molecular screening and immunohistochemistry for prion protein should complement traditional neuropathology to establish the diagnosis. The descriptive term of spongiform encephalopathy may now have to be abandoned in favour of prion disease.

Different susceptibilities of the geniculate and extrageniculate visual pathways to human Creutzfeldt-Jakob disease (a combined neurophysiological-neuropathological study)

Flash evoked visual potentials (FEPs) of 7 patients with advanced Creutzfeldt-Jakob disease (CJD) were compared with those recorded in 7 patients with senile dementia of the Alzheimer type (SDAT), in 13 age- and sex-matched healthy volunteers and in 7 neuropsychiatrically normal subjects whose occipital evoked responses were increased in amplitude (amplitude controls). Post-mortem examination was performed in 4 of 7 CJD patients in order to map pathological changes along the visual pathways, including the retino-geniculo-striate and extrageniculate pathways. Normal FEPs were typified by 2 constant early components (P1 and N2) followed by several (3 or more) late components that were characterized by marked interindividual variability. Amplitude controls had enlarged (from 14 to 44.8 microV, mean 25.7) P1 component. Both SDAT and CJD patients had normal early FEP waves (P1 and N2) and important alterations of the late FEP components. Moreover, a late positive component was responsible for abnormally enlarged FEPs (52.6 and 58.2 microV) in 2 CJD patients. Finally, electroretinograms, recorded in 1 CJD patient, were normal. These findings suggested relative functional integrity of the retino-geniculo-striate pathway associated with important dysfunction of the cortical visual processing in both SDAT and CJD patients. Pathological studies disclosed preservation of optic nerves, chiasmas, lateral geniculate nuclei and Gennari's strip of the striate cortex but associated with important spongiform change, neuronal loss and gliosis in the superior colliculi (layer II), pulvinar, extrastriate cortex and layers II-III, V and VI of the striate cortex. We conclude that different visual pathways have different susceptibilities to CJD: important functional and anatomical alterations of the intracortical and extrageniculate pathways contrast with relative preservation of the retino-geniculo-striate pathway.

Temporal evolution of electroencephalographic abnormalities in Creutzfeldt-Jakob disease

Frequent serial EEG investigations of three patients with neuropathologically confirmed Creutzfeldt-Jakob disease lasting 13, 24 and 68 weeks revealed typical periodic activity of short duration with stereotyped bilateral sharp waves at the 7th, 8th, and 12th week, respectively, after the onset of symptoms. During the later stages, there were several deviations from this typical pattern. However, periodic activity was preceded between the 3rd and 9th week by intermittent localized or lateralized delta rhythms, which gradually changed into periodic activity. This early temporal evolution of EEG abnormalities may be helpful in the early diagnosis of Creutzfeldt-Jakob disease when accompanied by other investigations to exclude other causes of intermittent delta rhythms.

White matter ultrastructural pathology of experimental Creutzfeldt-Jakob disease in mice

Creutzfeldt-Jakob disease (CJD), previously regarded as a neurodegenerative disorder strictly of the gray matter, occasionally occurs as a panencephalopathic form which is characterized by severe white matter damage. An ultrastructural study of the white matter pathology in mice experimentally infected with the Fujisaki strain of CJD virus revealed: (1) vacuoles within myelin sheaths, formed by splitting either at the major dense or intraperiod lines, or within axons; (2) macrophages filled with numerous myelin figures, lipid droplets and paracrystalline inclusions; (3) astrocytes actively digesting myelin debris; (4) unusual wrapping of several axons by a common myelin sheath; (5) vesicular degeneration of myelin sheaths; (6) close contact between numerous coated pits and outer myelin lamellae; and (7) proliferation of inner mesaxons. Our data indicate that the damage to myelinated axons in the panencephalopathic type of CJD is accomplished primarily by active degradation of myelin by macrophages and astrocytes and by formation of intra-axonal and intra-myelin vacuoles. The myelin vacuolation is most consistent with that produced by leukolysins released from activated macrophages and astrocytes.

Scrapie-induced diabetes mellitus in hamsters

Scrapie-infected hamsters had slightly elevated non-fasting plasma glucose levels, markedly abnormal glucose tolerance tests, and impaired release of insulin in response to a glucose load. Plasma cortisol levels were essentially the same in infected and uninfected animals. Histological examination of the pancreas revealed no morphological changes in infected animals with no alteration in distribution of cells secreting insulin, glucagon and somatostatin. In contrast, brains of scrapie-infected animals had the diffuse vacuolation typical of spongiform encephalopathy. These experiments suggest that scrapie-induced diabetes mellitus in hamsters may result from damage to the central nervous system.

Comparison of spongiform lesions in experimental scrapie and rabies in skunks

Striped skunks were inoculated intracerebrally with the scrapie agent (suspension of brain from a naturally infected Suffolk sheep) or intramuscularly with street rabies virus (suspension of salivary glands from naturally infected skunks). Those given the scrapie agent developed clinical signs of weakness, posterior ataxia, and emaciation after incubated periods of 8 to 23 months. Those inoculated with rabies virus developed clinical signs of rabies (aggressive behavior, hyperexcitability, ataxia and paralysis) after incubation periods of 20 to 62 days. The gross lesions in the brains of the skunks given the scrapie agent consisted of marked atrophy of the thalamus and moderate atrophy of the cerebrum. No gross lesions occurred in the rabid skunks. Histologically, the type of spongiform lesion in rabies was the same as that in scrapie. However, spongiform change of rabies infected brains was less extensive (only rarely affected the basal ganglia, hippocampus or hypothalamus) than that of brains infected with the scrapie agent and was characterized by fewer numbers of small vacuoles (as a proportion of total number of vacuoles) than occurred in scrapie spongiform change.

Rabies: spongiform lesions in the brain

Striped skunks (Mephitis mephitis) experimentally infected with street rabies virus developed spongiform lesions that light- and electron-microscopically were indistinguishable from those found in the transmissible spongiform encephalopathies of man and animals. These previously unreported lesions were also detected in naturally occurring cases of rabies. The spongiform lesions consisted of round or oval vacuoles in the neuropil, rarely in neuronal perikarya. The most severely affected areas were the thalamus and cerebral cortex. The implications of this finding include similarities in the pathogenetic mechanisms of rabies and the traditional spongiform encephalopathies and the possibility of lesion variation due to differences in rabies viral strains. The spongiform lesions of rabies will require consideration in differential diagnosis.

Creutzfeldt-Jakob disease: a case of 16 years' duration

A 46-year-old man with Creutzfeldt-Jakob disease confirmed postmortem had a 16-year course of very slowly progressing incoordination and mental deterioration, suggesting Alzheimer's disease. The disease course transformed abruptly into a 7-week terminal phase of florid Creutzfeldt-Jakob disease. Dementing illnesses of unknown cause were present in the patient's paternal lineage.

Ultrastructural alterations of the vestibular nuclei in Jacob-Creutzfeld disease

The morphological alterations of the vestibular nuclei in a case of Jacob-Creutzfeld disease were studied with light and electron microscope. The most prominent histological findings were the neuronal degeneration and neuronal loss resulting in a marked decrease of the total population, the increased reactive astrocytosis which demonstrated an extensive perivascular arrangement, the microgliosis and the interstitial spongiosis. At the ultrastructural level a marked dilatation of the astrocytic processes was seen. Most of them were completely transformed to sizeable cysts which were divided by membranous structures into smaller spaces. A large number of glycogen granules was accumulated into astrocytes and microglial cells. The neurons demonstrated numerous alterations such as (a) large accumulation of lysosomes, (b) fragmentation of the microtubules, (c) dilatation of the cisternae of the smooth endoplasmic reticulum, (d) mitochondrial abnormalities, (e) tremendous loss of the dendritic spines, (f) dilatation of the axonal terminals, (g) decrease of the number of the synaptic vesicles in the presynaptic terminal, (h) dilatation of the synaptic cleft, (j) dilatation and lysosomal accumulation in the postsynaptic component, (k) numerous multivesicular bodies and coated vesicles in pre- and postsynaptic terminals. In the neuropile space there were plenty of degenerated dendritic profiles. The degeneration of the vestibular nuclei of the brain stem was more extensive than the degeneration of the nuclei of the other brain stem cranial nerves.

Brain monoamine abnormalities in the two types of Creutzfeldt-Jakob disease

Analysis of monoamine concentrations in brain tissue was carried out on the two types of Creutzfeldt-Jakob disease (CJD). The results showed decreased levels of catecholamines compared to control cases in a number of areas, and the reductions were most pronounced for dopamine. In general, the case classified as the amyotrophic form of CJD showed a greater degree of a monoamine loss than the case with spongiform encephalopathy, which is the typical transmissible form of CJD. These findings support the scarce available data indicating disturbances in the catecholaminergic systems in these types of brain diseases, and may have therapeutic implications.

Familial cerebral amyloidosis and spongiform encephalopathy

Clinical and neuropathological investigations are presented of the "W" family in which there is a dominant inheritance of slowly progressive cerebellar ataxia and dementia. The disease is of insidious onset and its average duration more than 4 years. Pathological findings included amyloid deposition in cerebellar and cerebral tissue; vascular amyloid in one case; and spongiform encephalopathy and astrocytic hyperplasia typical of Creutzfeldt-Jakob disease. Neuritic plaques of the senile (Alzheimer) type were present to a lesser extent. This study confirms the familial association between cerebral amyloidosis and spongiform encephalopathy.

A typical presenile dementia. Report of an anatomo-clinical case and review of the literature

A clinico-pathological report is given of a case of dementia of frontal type with EEG changes, associated with a diffuse neuronal loss, subcortical gliosis and laminar spongiosis in the superficial part of the 2nd cortical layer. The authors discuss the cortical biopsy and the post-mortem findings in their case. They draw a comparison between their case an two conditions known as "progressive sub-cortical gliosis" and "Kraepelin's disease" which might be a single entity "atypical presenile dementia".

Panencephalopathic type of Creutzfeldt-Jakob disease: primary involvement of the cerebral white matter

Eight necropsy cases of a "panencephalopathic" type of Creutzfeldt-Jakob disease (CJD) in the Japanese are reported. The reasons why this type should be discussed separately from other types of CJD are that there is primary involvement of the cerebral white matter as well as the cerebral cortex, and that the white matter lesion of one Japanese human brain with CJD similar to the present group has been successfully transmitted to experimental animals.

On the transmission of dementia: a personal view of the slow virus problem

I came across Creutzfeldt-Jakob disease within a few weeks of starting work in the neuropathological laboratories at the Maudsley Hospital. The time was the 1940's, and Alfred Meyer, who had known both Creutzfeldt and Jakob in Germany, had already published his study on the possible link between amyotrophic lateral sclerosis and Creutzfeldt-Jakob disease (or spastic pseudosclerosis of Jakob as it was then called). Meyer's interest in the condition was therefore well known to British psychiatrists and neurologists, and patients who were thought to be suffering from this illness were referred to him. Routine post-mortem examinations would be duly carried out, perhaps by the psychiatric staff, and the brain, sometimes with the spinal cord, would be hardened in formalin and sent in a parcel to the Maudsley laboratories.

Multifocal pontine lesions in cancer patients treated with chemotherapy and CNS radiotherapy

Multifocal pontine lesions were found at postmortem examination in four patients with various types of malignancy. The patients had undergone extensive evaluation and treatment with multiple chemotherapy regimens as well as radiotherapy to the central nervous system. The histologic character and striking anatomic distribution of the pontine lesions are described and their possible pathogenesis discussed.

Latent form of Scrapie virus: a new factor in slow-virus disease

Scrapie is an unusual slow-virus disease of sheep which is very much like kuru and Creutzfeldt-Jakob disease, both fatal, slow neuological diseases of man. In mice, scrapie usually has an incubation period of about 6 months. Intraperitoneal inoculation of virus particles into newborn mice caused no disease, and there was no detectable virus replication for 1 year, but high titers of scrapie were present in the spleen and brain at 18 months. Virus replication occurred in mice injected from 4 days after birth by all inoculation routes, wheter or not they were injected with scrapie virus on day 0. The results suggest that scrapie virus replicates peripherally only in thymocytes, which are not present in mice until a few days after birth. The latent state suggests that the comparable human diseases could appear in later life as a result of perinatal infection. In some respects these diseases resemble premature senility.

An autopsy case of Creutzfeldt-Jakob disease with kuru-like neuropathological changes

An autopsy case of Creutzfeldt-Jakob disease with Kuru-like neuropathological changes which revealed clinically extrapyramidal, pyramidal and psychic symptoms is presented in this report. On microscopic examination, status spongiosus, neuronal degeneration, proliferation of hypertrophic astrocytes and numerous plaques were observed in the cerebrum and cerebellum accompanied with widespread demyelinization. These plaques which suggested Kuru plaques measuring 10 to 60 micron were strongly PAS positive and had a dense central core surrounded by a halo of fine radially arranged fibrils. As for the relationship between Creutzfeldt-Jakob disease and Kuru, the significance of these morphological changes is discussed.

Serial propagation of Creutzfeldt-Jakob disease in guinea pigs

The transmission and serial propagation of Creutzfeldt-Jakob disease from man to guinea pigs are reported. The latency, symptomatology, and morphology of the infection during the first four passages are presented. The incubation period between the first and subsequent passages was halved. One hundred percent take, morbidity, and mortality were achieved in all inoculated animals. All guinea pigs developed a subacute spongiform virus encephalopathy with marked neuronal destruction in the cerebral cortex and subcortical grey structures. The neuronal loss resulted in cerebral atrophy and hydrocephalus ex vacuo.

Spongy degeneration of grey matter in 3 children. Neuropathological report

Spongy degeneration of the cerebral grey matter is reported in 3 unrelated boys dying at the ages of 15 and 16 months and 3 years. Some of the neuropathological changes in the cases presented here and in other similar cases are like those in Creutzfeldt-Jakob disease and in kuru, conditions which have recently been transmitted to monkeys. The aetiology of spongy degeneration in children is not known, and it would be worth while to find out whether the disease is transmissible.