The 14-3-3 brain protein in cerebrospinal fluid as a marker for transmissible spongiform encephalopathies

Increase of neuron-specific enolase in patients with Creutzfeldt-Jakob disease

Creutzfeldt-Jakob disease (CJD) is a rare neurodegenerative human disorder with an incidence of one case per 1000000 per year. Recently new diagnostic tests such as neuron-specific enolase (NSE), S-100, tau-protein and protein 14-3-3 have been established as markers in prion diseases. NSE is elevated in case of rapid nerve cell loss so quantitative measurement of NSE in cerebrospinal fluid (CSF) might correlate with the disease progression. To further evaluate this hypothesis we analysed longitudinal CSF samples from 16 CJD patients. The first spinal tap was taken two weeks after the first clinical signs of a neurodegenerative disorder. This showed an elevation of NSE which continued during the course of the disease. Longitudinal examination of neuron-specific enolase in cerebrospinal fluid therefore may be useful for differentiation between CJD and other dementias.

Hashimoto's encephalitis as a differential diagnosis of Creutzfeldt-Jakob disease

OBJECTIVES

During an epidemiological study of Creutzfeldt-Jakob disease in Germany, Hashimoto's encephalitis was encountered as a differential diagnosis, which has not yet been described in this context.

METHODS

The symptoms and findings of seven patients who fulfilled the criteria for "possible" Creutzfeldt-Jakob disease are presented.

RESULTS

A Hashimoto's thyroiditis with antibodies against thyroglobulin or thyroid peroxidase, or both and a hypoechoic thyroid ultrasonogram were found in all cases. Analysis of CSF disclosed an increased leucocyte count in three patients, and a raised CSF:serum concentration ratio of albumin (QA1b) in four patients. The 14-3-3 protein, typical of Creutzfeldt-Jakob disease, could not be detected in any of our patients. No periodic sharp wave complexes, which are typical of Creutzfeldt-Jakob disease, were detected on EEG in any of the cases. By contrast with Creutzfeldt-Jakob disease, which leads to death within a few months, the patients with Hashimoto's encephalitis often recover quickly when treated adequately. All the patients improved after administration of corticosteroids.

CONCLUSION

The clinical symptomatology of both diseases may be very similar: dementia, myoclonus, ataxia, and personality change or psychotic phenomena are characteristic symptoms.

The prion diseases: Creutzfeldt-Jakob, Gerstmann-Sträussler-Scheinker, and related disorders

The prion diseases are an interesting group of neurodegenerative disorders for a variety of reasons. The most obvious is their property of transmissibility, but beyond that they constitute a fascinating example of the diversity of disease expression possible from a common etiologic factor. Thought of as "strains" in animals and phenotypes in humans, these varied expressions of prion disease are most likely due to subtle conformational changes in the pathogenic form of the prion protein. These strain-like characteristics are best exemplified in the genetic varieties of human prion disease in which specific mutations are associated with specific phenotypic profiles. This review attempts to highlight the clinical and pathologic features of the prion diseases with a particular focus on the genetic determinants that define the various familial forms and that modify sporadic and iatrogenic forms of the disease.

Penetrance and phenotypic expression of a mutation linked to Creutzfeldt-Jakob disease in the elderly

We have previously reported several carriers of the PRNP E200K point mutation among subjects aged over 65 years. In order to examine the prevalence of this mutation among demented subjects of Libyan and Tunisian origin and the clinical characteristics associated with it, we screened 58 elderly subjects belonging to this ethnic group. Five mutation carriers were identified, all of whom had cognitive deterioration consistent with primary degenerative dementia. All had low Hachinski ischemic scores (0.8 +/- 0.8, mean +/- SD) as compared with noncarriers (6.7 +/- 3.0; p = 0.011, Wilcoxon rank sum test). In addition to the cognitive decline, 4 carriers had additional cerebellar, pyramidal, or extrapyramidal findings compatible with the diagnosis of possible or probable Creutzfeldt-Jakob disease.

Prion diseases in man

Prion diseases are uncommon fatal neurodegenerative disorders which have gained scientific and public importance as a result of major advances in the understanding of the nature of the causative agent, and the emergence of new forms of these diseases in both animals and man. The transmissible agent in prion diseases is unique and is closely associated with an abnormal isoform of a widely distributed cell-surface glycoprotein, prion protein. The precise mechanisms of conversion to the abnormal isoform are unknown; changes in protein folding are of major importance. The abnormal isoform of the protein accumulates in the central nervous system in all prion diseases, but the processes involved in protein accumulation and the pathogenesis of neuronal dysfunction and cell death are poorly understood. Human prion diseases occur as sporadic, familial, and acquired disorders, the most recently identified of which is new variant Creutzfeldt-Jakob disease, which has been aetiologically linked to exposure to the bovine spongiform encephalopathy agent through the food chain. Surveillance of human prion diseases will be crucial in the assessment of the impact of this new disease in the United Kingdom and elsewhere. Effective surveillance depends on accurate diagnosis, which in turn places a high priority on autopsy in suspected cases; neuropathology is essential for the diagnosis of human prion diseases. Phenotypic variation is prominent in all forms of human prion disease; future classifications of these disorders are likely to incorporate genetic and biochemical data in addition to clinical and pathological parameters.

[Anesthesia and non-conventional transmissible agents (or prion diseases)]

The transmissible spongiform encephalopathies (TSE) represent a group of neurodegenerative diseases with lethal outcome. They include Creutzfeldt-Jakob disease (CJD) and kuru, among others in humans, scrapie in sheep and spongiform encephalopathy in cattle (bovine spongiform encephalopathy: BSE). Some are autosomal dominant disorders like CJD, Gerstmann-Straüssler-Scheinker disease (GSS), with point mutation of the prion protein gene. Most of these diseases are idiopathic rather than sporadic, latrogenic CJD could be obtained by central inoculation (neurosurgical instruments or dura mater grafts) or by peripheral inoculation (pituitary hormone therapy). A new variant clinicopathological type of CJD (nvCJD) has been reported. The nvCJD has strain characteristics distinct from other types of CJD, close to those of BSE transmitted (studies with intracerebral inoculation), consistent with BSE being the source of this new disease. All of these spongiform encephalopathies (SE) are characterized by spongiform degeneration of the brain, reactive gliosis in the cortical and subcortical gray matter, neuronal loss and presence of the abnormal isoform of the cellular prion protein (PrPc). In prion disease, PrPc undergoes conformational changes involving a shift from alpha-helix to beta-sheet structure. These neurologic lesions are characterized by major variations from case to case. Neuropathological studies in sporadic CDJ have emphasized phenotypic variations. Clinical presentation with a wide spectrum of manifestations is a rapidly progressive dementia, associated with myoclonus or akinetic mutism and cortical blindness. The clinical course is atypical and when the characteristic triphasic abnormal EEG of CJD is absent, there is an urgent need for a premortem diagnostic test. Histopathological examination of a brain biopsy carries a risk of major morbidity and may miss the site of disease. The 14-3-3 immunoassay of cerebrospinal fluid strongly supports a diagnosis of CJD. Western blot analysis of human tonsil biopsy may allow an early or preclinical diagnosis. It has been suggested that CJD might be transmitted by blood products derived from patients with CJD during the prodromal stage, although CJD linked aetiologically to blood transfusion has not been demonstrated. In animal studies, intracerebral inoculation of infected cells has been associated with development of disease, but never after peripheral inoculation into the blood stream. For the most part of conformational changes of PrPc, the remarkable resistance of the infectious agent (PrP alone or combined) to ordinary sterilising procedures is a major problem. Because of this resistance, current recommendations are to recognize patients at risks and to use disposable medical devices. This is particularly true in anaesthesia during endotracheal intubation, spinal anaesthesia, and to a lesser extent with peripheral nerve blocks. All instruments used for patients with CJD must be destroyed. The economic consequences of these measures have highlighted the essential importance of an early diagnosis.

Creutzfeldt-Jakob disease: clinical features, epidemiology and tests

Creutzfeldt-Jakob disease (CJD) is now recognized to occur in four main forms: classical sporadic, genetic, iatrogenic and new variant. These are briefly described. The evidence that new variant disease is due to bovine spongiform encephalopathy (BSE) is reviewed. In CJD, disease and infectivity are associated with the accumulation of an abnormal form of a normal cellular protein. Protein analysis and the study of the gene which encodes for this protein have therefore played an important role in understanding CJD. Diagnostic tests for CJD are discussed with particular reference to the detection of the 14-3-3 protein in the cerebrospinal fluid (CSF).

14-3-3 proteins in neuronal development and function

The 14-3-3 proteins are small, cytosolic, evolutionarily conserved proteins expressed abundantly in the nervous system. Although they were discovered more than 30 yr ago, their function in the nervous system has remained enigmatic. Several recent studies have helped to clarify their biological function. Crystallographic investigations have revealed that 14-3-3 proteins exist as dimers and that they contain a specific region for binding to other proteins. The interacting proteins, in turn, contain a 14-3-3 binding motif; proteins that interact with 14-3-3 dimers include PKC and Raf, protein kinases with critical roles in neuronal signaling. These proteins are capable of activating Raf in vitro, and this role has been verified by in vivo studies in Drosophila. Most interestingly, mutations in the Drosophila 14-3-3 genes disrupt neuronal differentiation, synaptic plasticity, and behavioral plasticity, establishing a role for these proteins in the development and function of the nervous system.

Scrapie

Scrapie and other transmissible spongiform encephalopathies (TSEs) are characterized by similar pathology, biochemistry and genetics. The PrP protein and its conversion to the disease-related isoform, PrPSC, are crucial for the development of all TSEs. Although scrapie is more often studied in laboratory rodents, it is not a natural disease of these animals, and much can be learned from the normal hosts, sheep. Disease incidence is linked to polymorphisms and mutations of the PrP gene. The complex relationships between PrP genotype and the survival of sheep subjected to scrapie infection are now being investigated in terms of the different structure of the PrP protein molecules produced by each allele. It is these structures and their differing abilities to convert to PrPSC that hold the key to understanding why TSEs occur.

Tonsillar biopsy and PrPSc detection in the preclinical diagnosis of scrapie

Preliminary findings have indicated that in naturally infected sheep, fully susceptible to scrapie (VRQ-homozygous), PrPSc can be detected in the tonsils approximately one year before the expected onset of clinical disease, whereas no immunostaining can be detected in animals with a semi-resistant genotype. This paper describes the technique for taking tonsillar biopsies from sheep and gives the results of the completed experiment. In another experiment PrPSc was detected even earlier in comparable VRQ-homozygous sheep born and raised in different surroundings. At three-and-a-half months of age no PrPSc could be detected in three homozygous susceptible sheep (VRQ/VRQ), but PrPSc was detected at four months in one similar sheep. At eight months of age all seven sampled VRQ/VRQ sheep showed positive immunostaining in the biopsies, but none of the biopsies from three VRQ/ARQ heterozygotes showed any immunostaining; they were positive when sampled at 14 to 15 months of age. Biopsies from VRQ/ARR sheep were negative throughout this period. On the basis of the established or expected incubation period, PrPSc could thus be detected in the tonsils of live susceptible animals at between one-third and a half of the incubation period, more than one-and-a-half years before clinical signs normally appear in both these genotypes.

The initial recognition and diagnosis of dementia

Dementia is characterized by a decline in cognition, behavioral disturbances, and interference with daily functioning and independence. Diagnosis is sometimes delayed as patients or family members often misattribute obvious manifestations of cognitive decline to normal aging rather than to the onset of a degenerative disease. Many physicians do not perform mental status examinations or do not use them effectively to detect early symptoms. Clinical markers are available to decrease the difficulty in distinguishing dementia from depression and confusional states such as delirium. Alzheimer's disease (AD) is the most common form of dementia; others include rapidly progressive dementias, dementias associated with strokes and Parkinson's disease, and frontotemporal dementias. Often, AD coexists with other forms of dementia. Sensitivity to early warning signs, interviews with family members, and mental status examinations are essential to early detection of AD, and will prove useful to primary-care physicians who care for older patients.

New variant Creutzfeldt-Jakob disease

Since the report of new variant Creutzfeldt-Jakob Disease (nvCJD) in humans last year, the search was on for direct evidence to link the condition to Bovine Spongiform Encephalopathy (BSE). The first case nvCJD was noted 10 years after the recognition of BSE in UK cattle. A direct link is now established. There are, however, some 'protective' mechanisms, the most important of which are the inefficiency of the gastric route of introducing the infected material, the species barrier and genetic 'predisposition'. None of these is full proof and time will tell whether feeding ruminants with their own species will turn out to be a major public health disaster?

Identification in Israel of 2 Jewish Creutzfeld-Jakob disease patients with a 178 mutation at their PrP gene

Among the dozen known mutations in the PrP gene which segregate with the inherited prion diseases, only 2 mutations have been described in Israel so far: the codon 200 mutation in Creutzfeldt-Jakob disease (CJD) affected Libyan Jews, and the codon 102 mutation in 1 Jewish Gerstmann-Straussler-Scheinker (GSS) affected pedigree of German origin. We report here 2 unrelated CJD178 cases affected by a unique phenotype: aphemia, apraxia, uncontrolled laugh and no ataxia. As opposed to other CJD178 patients, in these patients, the signal transduction protein 14-3-3, recently suggested as a CJD marker, was detected in the cerebrospinal fluid samples by immunostaining. The D178N mutation, known to be linked to 2 different phenotypes: Fatal Familial Insomnia (FFI) and CJD, was not described so far among Jews. The phenotype reported here, although it shares a common Va1129/Asn178 haplotype with the previously described CJD178, may point to a different clinical subtype of CJD178.

Transmissible spongiform encephalopathies in food animals. Human food safety and animal feed safety concerns for veterinarians

This article presents a brief overview of transmissible spongiform encephalopathies (TSEs) using examples of diseases that provide evidence supporting oral transmission of the agent. Agent theories are described briefly in general terms. Scrapie, bovine spongiform encephalopathy (BSE), chronic wasting disease, and transmissible mink encephalopathy are discussed to improve disease recognition by the food animal practitioner. Control programs for scrapie and BSE are described and the role of the veterinarian in animal feed and human food safety is related to TSEs.

Diagnosis of Creutzfeldt-Jakob disease by measurement of S100 protein in serum: prospective case-control study

OBJECTIVE

To analyse serum concentrations of brain specific S100 protein in patients with Creutzfeldt-Jakob disease and in controls.

DESIGN

Prospective case-control study.

SETTING

National Creutzfeldt-Jakob disease surveillance unit.

SUBJECTS

224 patients referred to the surveillance unit with suspected Creutzfeldt-Jakob disease and 35 control patients without dementia.

MAIN OUTCOME MEASURE

Serum concentration of S100 protein in patients with Creutzfeldt-Jakob disease, in patients with other diseases causing dementia, and in the control group.

RESULTS

Of the 224 patients with suspected Creutzfeldt-Jakob disease, 65 were classed as definitely having the disease after neuropathological verification, an additional 6 were classed as definitely having the disease as a result of a genetic mutation, 43 as probably having the disease, 36 as possibly having the disease, and 74 patients were classed as having other disease. In the 108 patients classed as definitely or probably having Creutzfeldt-Jakob disease the median serum concentration of S100 was 395 pg/ml (SD 387 pg/ml). This was significantly higher than concentrations found in the 74 patients classed as having other diseases (median 109 pg/ml; SD 177 pg/ml; P = 0.0001). At a cut off point of 213 pg/ml sensitivity for the diagnosis of the disease was 77.8% (95% confidence interval 68.8% to 85.2%) and specificity was 81.1% (70.3% to 89.3%). There was a significant difference in survival at different concentrations of S100 in Kaplan-Meier curves (P = 0.023).

CONCLUSION

Measurement of serum concentrations of S100 is a valuable tool which can be used more easily than tests on cerebrospinal fluid in the differential diagnosis of Creutzfeldt-Jakob disease. More studies are needed to determine whether serial testing of serum S100 improves diagnostic accuracy.

Diagnosis of Creutzfeldt-Jakob disease and related human spongiform encephalopathies

Spongiform encephalopathies are transmissible diseases (TSE) of animals and humans. With the appearance of bovine spongiform encephalopathy (BSE) in 1986 and in 1996 with the identification of an apparently new variant of the human spongiform encephalopathy Creutzfeldt-Jakob disease (CJD), great concerns of a potential transmission of BSE to humans have been voiced. The agent known to transmit CJD and other human and animal spongiform encephalopathies is designated as prion, i.e., proteinaceous infectious agent, due to the absence of evidence for the involvement of a nucleic acid in disease transmission. In humans the clinical diagnosis of typical CJD cases can now be supported by paraclinical parameters. Electroencephalographic changes, so called periodic sharp wave complexes, are pathognomonic for CJD but by no means specific. The detection of neuronal enzymes in the cerebrospinal fluid (CSF) such as neuron specific enolase (NSE) or glial proteins such as S-100 aids greatly in the diagnosis of a human spongiform encephalopathy. By far the most specific marker in CSF are a group of proteins designated 14-3-3. Current evidence suggests that by including elevated levels of NSE (> or = 35 ng/mL), S-100 (> or = 8 ng/mL) and tau protein in the CSF and the presence of 14-3-3, a laboratory supported diagnosis of CJD can be achieved which in the appropriate clinical setting has a better diagnostic accuracy than the currently used clinical and paraclinical diagnostic criteria alone.

Clinical changes and EEG patterns preceding the onset of periodic sharp wave complexes in Creutzfeldt-Jakob disease

The conversion of EEG findings and the evolution of clinical signs was investigated in 7 CJD patients who underwent serial EEG recordings along the course. At the onset of PSWC (mean 8.7 weeks), 5 patients had already progressed to akinetic mutism (characterized by loss of verbal contact and directed responses); and a CJD-typical-movement disorder (myoclonia, exaggerated startle reaction or focal dyskinesia) had started in 5 patients. When akinetic mutism commenced (on average at 7.5 weeks), runs of frontal intermittent non-peaked rhythmical delta activity (FIRDA) were found in all cases. These were later replaced by PSWC in 6 patients (interval 1 to 3 weeks). Occurrence of PSWC was often negatively related to external stimuli (2 of 6 cases), and sedative medication (all patients tested). We conclude that the selection of EEG recording dates to detect PSWC in CJD-candidates should be guided by detailed information about movement disorders and conscious level. Regarding the short survival time after their onset (average 8 weeks), PSWC usually mark the terminal stage of CJD. To detect PSWC, especially, EEG registrations in advanced stages are often necessary. In earlier disease stages, FIRDA-like EEG activities should be regarded as compatible with this diagnosis, and encourage further EEG studies for the demonstration of PSWC in a more advanced stage of CJD.

Detection of 14-3-3 protein in the cerebrospinal fluid supports the diagnosis of Creutzfeldt-Jakob disease

The analysis of 14-3-3 protein in cerebrospinal fluid (CSF) was shown to be highly sensitive and specific for the diagnosis of Creutzfeldt-Jakob disease (CJD). However, the predictive value of this test in the clinical diagnosis of, and its relation to, sporadic, genetic, and iatrogenic CJD cases have yet to be established. CSF samples of suspect CJD cases seen in the prospective German surveillance study were tested for the presence of 14-3-3 protein by using a modified western blot (WB) technique. WB detected 14-3-3 protein in 95.4% of definite and 92.8% of probable cases. In two patients classified initially as not having CJD the test was positive, and both were later proved to have definite CJD. The positive predictive value is 94.7% and the negative predictive value is 92.4%. False-positive results in a single CSF analysis were seen in patients with herpes simplex encephalitis, hypoxic brain damage, atypical encephalitis, intracerebral metastases of a bronchial carcinoma, metabolic encephalopathy, and progressive dementia of unknown cause. WB analysis for 14-3-3 protein was positive in only 5 of 10 cases of familial forms of spongiform encephalopathies. CSF analysis for 14-3-3 protein should thus be performed in any case suspect for CJD.

Identification of a prion protein epitope modulating transmission of bovine spongiform encephalopathy prions to transgenic mice

There is considerable concern that bovine prions from cattle with bovine spongiform encephalopathy (BSE) may have been passed to humans (Hu), resulting in a new form of Creutzfeldt-Jakob disease (CJD). We report here the transmission of bovine (Bo) prions to transgenic (Tg) mice expressing BoPrP; one Tg line exhibited incubation times of approximately 200 days. Like most cattle with BSE, vacuolation and astrocytic gliosis were confined in the brainstems of these Tg mice. Unexpectedly, mice expressing a chimeric Bo/Mo PrP transgene were resistant to BSE prions whereas mice expressing Hu or Hu/Mo PrP transgenes were susceptible to Hu prions. A comparison of differences in Mo, Bo, and Hu residues within the C terminus of PrP defines an epitope that modulates conversion of PrPC into PrPSc and, as such, controls prion transmission across species. Development of susceptible Tg(BoPrP) mice provides a means of measuring bovine prions that may prove critical in minimizing future human exposure.

Understanding Creutzfeldt-Jakob disease

The "mad cow disease" that decimated cattle in England has brought wide-spread attention to a similar disease in humans, Creutzfeldt-Jakob disease (CJD). This has led to concerns about the transmissibility and contagiousness of the infectious agent from possible CJD patients to health care workers and family members. Despite these worries, the occurrence of CJD in the human population has remained stable over the years at an incidence of about one person per million in the United States population, and increasing to six individuals per million for the older-than-60 age group. This article will review the etiology, clinical manifestations, and potential for transmission of this unusual infectious agent.

Elevation of apolipoprotein E in the CSF of cattle affected by BSE

The cerebrospinal fluid (CSF) of patients suffering from Creutzfeldt-Jakob disease (CJD) display two unique polypeptide chains by two-dimensional polyacrylamide gel electrophoresis (2-D PAGE). In the absence of a well-defined ante-mortem diagnostic test for bovine spongiform encephalopathy (BSE), spinal fluid samples of eight normal cows and eight cows known to carry BSE by post-mortem histological analysis were investigated to verify if equivalent polypeptides were present. Proteins with similar migration to human CJD polypeptides were not detected. But surprisingly, a cluster of polypeptide spots that was faint or not detected in normal bovine CSF samples was found to be elevated or massively increased in BSE CSF samples (more than 10-fold increase). These elevated polypeptide chains were identified as apolipoprotein E.

Interaction of phosphorylated tryptophan hydroxylase with 14-3-3 proteins

Rabbit brain tryptophan hydroxylase (TPH) has been expressed in insect cells (Spodoptera frugiperda) as a histidine-tagged enzyme. The specific activity of the purified fusion enzyme is 80 nmol of 5-hydroxytryptophan/min/mg. Multifunctional regulatory 14-3-3 proteins were purified from fresh bovine brain. Phosphorylation and 14-3-3 proteins play important roles in the regulation of TPH activity. We have found that phosphorylation of TPH by cAMP-dependent protein kinase increased the activity of the hydroxylase by 25-30% and that 14-3-3 proteins increased the hydroxylase activity of phosphorylated TPH by approximately 45%. Under these conditions, the 14-3-3 proteins were not phosphorylated, and unphosphorylated TPH was not activated by 14-3-3 proteins. Surface plasmon resonance analysis demonstrated that 14-3-3 proteins bind to phosphorylated TPH with an affinity constant (Ka) of 4.5 x 10(7) M-1. Binding studies using affinity chromatography also showed that 14-3-3 proteins interact with phosphorylated TPH. The dephosphorylation of TPH by protein phosphatase-1 was inhibited by 14-3-3 proteins. Our results demonstrate that 14-3-3 proteins form a complex with phosphorylated brain TPH, thereby increasing its enzymatic activity and inhibiting its dephosphorylation.

Prion diseases and the BSE crisis

Bovine spongiform encephalopathy (BSE) and human Creutzfeldt-Jakob disease (CJD) are among the most notable central nervous system degenerative disorders caused by prions. CJD may present as a sporadic, genetic, or infectious illness. Prions are transmissible particles that are devoid of nucleic acid and seem to be composed exclusively of a modified protein (PrPSc). The normal, cellular prion protein (PrPC) is converted into PrPSc through a posttranslational process during which it acquires a high beta-sheet content. It is thought that BSE is a result of cannibalism in which faulty industrial practices produced prion-contaminated feed for cattle. There is now considerable concern that bovine prions may have been passed to humans, resulting in a new form of CJD.

New variant Creutzfeldt-Jakob disease: neurological features and diagnostic tests

BACKGROUND

In April, 1996, ten cases of Creutzfeldt-Jakob disease (CJD) with an apparently new clinicopathological phenotype were published and it was suggested that these new variant cases (nvCJD) might be causally linked to bovine spongiform encephalopathy (BSE). There have now been 21 cases of nvCJD in the UK and one case in France. We report clinical features and diagnostic test results of the first 14 cases of nvCJD in the UK.

METHODS

Case ascertainment of CJD was mainly by direct referral from neurologists and neuropathologists. Clinical and investigate details were obtained by interview with patients' relatives and by examination of case notes. Ten cases in this report were examined while alive. Prion protein (PrP) gene analysis was carried out with informed consent from the patient or from a relative. The diagnosis of nvCJD was established histologically.

FINDINGS

Eight cases were women. Mean age at onset of symptoms was 29 (16-48) years and the median duration of illness was 14 (9-35) months. All patients had early psychiatric symptoms, most often depression, and 13 were seen by a psychiatrist early in the clinical course. Eight patients developed early sensory symptoms which were persistent and often painful. Neurological signs, including ataxia and involuntary movements, developed in all cases and towards the end of the illness, most had akinetic mutism. The electroencephalogram was abnormal in most patients but typical periodic complexes of CJD were not seen in any case. Cerebral imaging was usually normal or showed non-specific abnormalities; in two cases magnetic-resonance imaging scans showed high signal in the thalamus.

INTERPRETATION

Clinical features in these cases are similar and relatively distinct from other forms of CJD, suggesting that this is a new clinical phenotype consistent with a single strain of infectious agent. There is, however, some overlap with atypical cases of sporadic CJD, and the diagnosis of nvCJD remains dependent on neuropathological confirmation.

Control of scrapie eventually possible?

After a brief description of the scrapie situation in the Netherlands, the technical progress made in aspects of scrapie diagnosis is reported. Emphasis is placed on the use of immuno-histochemistry (IHC) in the post-mortem histological diagnosis and on the recently published preclinical test for scrapie, in which IHC is applied to tonsillar biopsies. These two approaches use the same IHC technique and enable us to confirm suspected scrapie in individual animals, and for certain genotypes even in the preclinical phase. The tonsillar biopsy method could eventually lead to an infection- or PrPSc-detection method at flock level. Further work is required, including validation of the assay for various breeds, genotypes, and strains of the agent, and the conversion of the test into a more practical assay. The article continues with a discussion of several scrapie control strategies, describing briefly schemes tried in various countries, and elaborates on a proposed scrapie control scheme that could be suitable for the Netherlands. This scheme is essentially based on breeding for resistance, based on PrP genotyping.

From Creutzfeldt-Jakob disease to the mad cow epidemic

Hans-Gerhard Creutzfeldt and Alfons Jakob independently authored clinical and pathologic descriptions of a new syndrome in the 1920s. This syndrome, which subsequently came to be named after them, was characterized by dementia, motor and coordination abnormalities, a fatal course, and pathologic findings of diffuse spongiform neuronal degeneration. Although it appeared for many years to be little more than a medical curiosity, Creutzfeldt-Jakob disease attained widespread attention by its pathologic similarity to kuru and bovine spongiform encephalopathy, "mad cow disease." Because there are sporadic, familial, and iatrogenic forms of Creutzfeldt-Jakob disease, it is considered to have both genetic and infectious aspects. Although its causation has for some time been ascribed to "slow viruses," the etiology of Creutzfeldt-Jakob disease is currently thought to be due to prions, small proteinaceous infectious particles that have genetic encoding. The debate regarding whether the appearance of atypical Creutzfeldt-Jakob disease can be linked to the epidemic of "mad cow disease" is currently unresolved.

A 66-year-old woman with a rapidly progressing dementia and basal ganglia involvement

A 66-year-old woman presented with a rapidly progressive dementia initially characterized by an auditory agnosia. She experienced a rapid progression of her aphasia and developed ataxia and myoclonus. An initial neurological evaluation suggested a left parieto-temporal lesion, however, neuroimaging did not reveal any. An MRI of her brain demonstrated highly focal T2 hyperintensities in her basal ganglia. The patient was diagnosed with Creutzfeldt-Jacob Disease (CJD) on the basis of the presence of two proteins in the CSF that are highly sensitive and specific for CJD. Pathological examination confirmed the diagnosis. The differential diagnosis and utility of MRI in patients with CJD is discussed.

Elevated levels of tau-protein in cerebrospinal fluid of patients with Creutzfeldt-Jakob disease

Creutzfeldt-Jakob disease (CJD) is a rare, fatal, neurodegenerative disease caused by a transmissible agent designated as proteinaceous infectious agent (prion). Searching for biochemical markers of CJD, we analysed cerebrospinal fluid (CSF) samples of 53 patients for tau-protein using an enzyme linked immunoassay (ELISA). In a group of 21 patients with definite CJD seen in the German case control study for CJD, tau-protein concentrations in CSF were significantly higher than in two control-groups of patients with other diseases (median 13,153 pg/ml, range 1,533-27,648 pg/ml; P = 0.0001). One group comprised 19 patients who were seen in the same study and were diagnosed as having other dementing diseases (tau concentration: median 558 pg/ml, range 233-1,769 pg/ml). The second control group comprised 13 patients from our hospital with no dementing disease (tau concentration: median 296 pg/ml, range 109-640 pg/ml). We conclude that determination of tau protein levels in CSF is a useful marker for laboratory diagnosis of CJD.

Creutzfeldt-Jakob disease: therapeutic strategies

Creutzfeldt-Jakob disease (CJD) is a rare neurodegenerative illness which belongs to the group of transmissible subacute spongiform encephalopathies (TSSE). Today, no treatment is available for TSSE. The appearance of a new variant of CJD, which affects young people and could be linked to so-called ;mad cow disease', has stimulated researchers to develop new therapies against CJD. A few drugs have already been shown to delay the onset of experimental TSSE. They could contribute to the understanding of the pathogenic mechanisms involved in TSSE and, therefore, could be the basis for therapeutic strategies against CJD.

BSE: a decade on--Part 2

Predicted numbers vary widely but the most authoritative estimate is that about 6950 cases of BSE will occur in cattle in the UK during 1997-2001 if new infections via feed have ceased as expected and if 10% maternal transmission occurs in the last half-year of the maternal incubation period. This assumes no culling or premature slaughter. Agreed cull strategies would reduce these numbers considerably and accelerate the observed rate of decline of the disease, but there is no scientific necessity for any cull. Bovine products that were banned as specified bovine offals in 1989/90 and as specified bovine materials by successive legislation are now excluded from the food and feed chains. As this second of the two-part article on BSE shows, there has been slippage in some of our control measures, but public and animal health are adequately protected if the legislation that has been evolved is enforced along present lines. Meanwhile, for human beings, bovine milk is safe to drink and beef is safe to eat.

The assay development of a molecular marker for transmissible spongiform encephalopathies

The transmissible spongiform encephalopathies are a group of neurodegenerative diseases which include Creutzfeldt-Jakob disease (CJD) in humans, scrapie in sheep, and bovine spongiform encephalopathy (BSE) in cattle. Two-dimensional electrophoresis of proteins was previously used to identify two marker proteins, 130/131, which are selectively present in the cerebrospinal fluid (CSF) of patients with CJD and not in patients with other dementias. The recent characterization of these proteins by amino acid sequencing has identified them as members of the 14-3-3 family of proteins. Polyclonal antibodies against 14-3-3 (all isoforms), 14-3-3 gamma, 14-3-3 beta, and 14-3-3 theta are immunoreactive with a 30 kDa marker band from CJD CSF. Silver staining of two-dimensional electrophoresis separated BSE CSF proteins does not identify a similar marker. However, 14-3-3 immunoreactivity is found in cattle CSF when these proteins are blotted to polyvinylidene difluoride but not when blotted to nitrocellulose.

Is Creutzfeldt-Jakob disease transmitted in blood?

Creutzfeldt-Jakob disease (CJD) has been considered infectious since the mid-1960s, but its transmissibility through the transfusion of blood or blood products is controversial. The causative agent's novel undefined nature and resistance to standard decontamination, the absence of a screening test, and the recognition that even rare cases of transmission may be unacceptable have led to the revision of policies and procedures worldwide affecting all facets of blood product manufacturing from blood collection to transfusion. We reviewed current evidence that CJD is transmitted through blood.

Protein markers in cerebrospinal fluid from BSE-affected cattle

Two-dimensional gel electrophoresis was used to analyse cerebrospinal fluid (CSF) from 75 suspect cases of bovine spongiform encephalopathy (BSE), 61 of which were confirmed by post mortem brain histopathology, and 38 normal cattle. CSF samples were also examined from cattle killed at periodic intervals through the incubation period following experimental challenge. Consistent changes were recorded in all CSF samples from the confirmed cases of natural BSE and also from cattle showing early signs of experimental disease. The changes consisted of an increased intensity of staining of apolipoprotein E and the presence of two protein spots, as yet unidentified, of molecular weights 35 and 36 kDa, both with a pI of 5.5. These changes were absent in the CSF samples from the normal cattle, from the clinically suspect cattle which were not confirmed as BSE and from the experimentally challenged cattle in the preclinical phase of infection.

Diagnosing Creutzfeldt-Jakob disease

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Diagnosis of Creutzfeldt-Jakob disease by two-dimensional gel electrophoresis of cerebrospinal fluid

BACKGROUND

The diagnosis of Creutzfeldt-Jakob disease (CJD) is based on clinical and electroencephalographic criteria which do not allow a reliable diagnosis to be made during life.

METHODS

Serum and cerebrospinal fluid (CSF) samples were obtained after informed consent from relatives of suspected cases of CJD referred to the German CJD surveillance unit. CSF samples from 58 definite (neuropathologically verified), 46 probable, and 34 possible CJD cases, and from 44 patients without CJD were analysed by two-dimensional gel electrophoresis (2-DE). Two investigators blinded to clinical findings recorded the presence of two proteins, p130/131. The kappa value for the level of agreement between these investigators was calculated. Results obtained were compared with the determination of neuron-specific enolase (NSE) in CSF. NSE concentrations of more than 35 ng/mL were considered indicative of CJD.

FINDINGS

p130/131 was detected in 81% of definite (47/58), 80% of probable (37/46), 68% of possible (23/34) CJD cases, and in none of the other 44 cases. NSE concentrations of more than 35 ng/mL were seen in 79% of definite (46/58), 80% of probable (37/46), 59% of possible (20/34) CJD cases, and 9% of other cases (4/43). The positive predictive value for 2-DE of CSF is 100% and the negative predictive value is 69%. The level of agreement for the detection of p130/131 by two evaluators in a subset of 141 2-DE gels was a kappa of 0.93 (95% CI 0.86-0.99). Of 13 cases initially classified as possible and later reclassified as definite, ten cases were identified correctly by the 2-DE analysis, indicating a better diagnostic accuracy of this test compared with the current clinical classification. None of nine cases classified as other by neuropathology had p130/131 in 2-DE.

INTERPRETATION

2-DE for p130/131 is a specific test for the diagnosis of CJD. These data suggest including detection of p130/131 as a criterion for the diagnosis of probable CJD in addition to the currently accepted criteria of a rapidly progressive dementia of less than 2 years duration, typical neurological signs, and periodic sharp-wave complexes in the EEG.