Comparison of nanofiltration efficacy in reducing infectivity of centrifuged versus ultracentrifuged 263K scrapie-infected brain homogenates in "spiked" albumin solutions.

Background: The safety of plasma-derived products is of concern for possible transmission of variant Creutzfeldt-Jakob disease. The absence of validated screening tests requires the use of procedures to remove or inactivate prions during the manufacture of plasma-derived products to minimize the risk of transmission. These procedures need proper validation studies based on spiking human plasma or intermediate fractions of plasma fractionation with prions in a form as close as possible to that present in blood.

Failure of immunocompetitive capillary electrophoresis assay to detect disease-specific prion protein in buffy coat from humans and chimpanzees with Creutzfeldt-Jakob disease.

The emergence of a new environmentally caused variant of Creutzfeldt-Jakob disease (vCJD), the result of food-born infection by the causative agent of bovine spongiform encephalopathy (BSE), has stimulated research on a practical diagnostic screening test. The immunocompetitive capillary electrophoresis (ICCE) assay has been reported to detect disease-specific, proteinase-resistant prion protein (PrPres) in the blood of scrapie-infected sheep. We have applied this method to blood from CJD-infected chimpanzees and humans.

Early spread of scrapie from the gastrointestinal tract to the central nervous system involves autonomic fibers of the splanchnic and vagus nerves.

Although the ultimate target of infection is the central nervous system (CNS), there is evidence that the enteric nervous system (ENS) and the peripheral nervous system (PNS) are involved in the pathogenesis of orally communicated transmissible spongiform encephalopathies. In several peripherally challenged rodent models of scrapie, spread of infectious agent to the brain and spinal cord shows a pattern consistent with propagation along nerves supplying the viscera. We used immunocytochemistry (ICC) and paraffin-embedded tissue (PET) blotting to identify the location and temporal sequence of pathological accumulation of a host protein, PrP, in the CNS, PNS, and ENS of hamsters orally infected with the 263K scrapie strain.

Effect of repeated oral infection of hamsters with scrapie.

The development of a transmissible spongiform encephalopathy upon uptake of the infectious agent in feed was studied in the model system scrapie in hamsters. Compared to single dosing, repeated dosing caused disease at a considerable higher incidence. The risk of infection was higher when the time interval between repetitive dosing was short.

Evidence for an alternative direct route of access for the scrapie agent to the brain bypassing the spinal cord.

Scrapie is a disease which occurs naturally in sheep and goats and belongs to a group of neurodegenerative disorders known as transmissible spongiform encephalopathies, or TSEs. There is currently no cure for TSEs, and the causative agent has not yet been identified. Numerous experiments, however, have addressed the pathogenetic process following a TSE infection.

Highly infectious purified preparations of disease-specific amyloid of transmissible spongiform encephalopathies are not devoid of nucleic acids of viral size.

An efficient purification protocol for infectivity causing a transmissible spongiform encephalopathy (TSE) is described. From fractions purified by this protocol about 3 x 10(8) LD50 but only 3 ng of nucleic acids per gram of brain material can be isolated from all TSE-affected brains (hamster, human, sheep, cattle). By PAGE such fractions from brains of infected and control hamsters contained only one distinct nucleic acid band of 1.

[Creutzfeldt-Jakob disease in Austria].

Between 1969 and 30th June 1996, Creutzfeldt-Jakob disease (CJD) was definitively diagnosed in 88 Austrian patients by autopsy and/or biopsy. The number of diagnosed cases has steadily increased in recent years (average incidence in 1969-1985: 0.18 per million; 1986-1994: 0.

Sequential appearance and accumulation of pathognomonic markers in the central nervous system of hamsters orally infected with scrapie.

Both infectivity and TSE-specific amyloid protein (also referred to as protease resistant- or prion protein, PrP) are pathognomonic markers for transmissible spongiform encephalopathies (TSE). This paper presents a new densitometric method for the quantification of TSE-specific amyloid protein and its application to studying the pathogenesis of scrapie in Syrian hamsters after infection with scrapie strain 263K. A first study established a close correlation between infectivity and TSE-specific amyloid protein with a doubling time of 2-2.

Creutzfeldt-Jakob disease in Austria.

Between 1969 and 30 September 1995, 79 Austrian patients had Creutzfeldt-Jakob disease (CJD) diagnosed neuropathologically by necropsy or biopsy. The annual incidence has significantly increased in recent years (average 0.18 per million in 1969-85, and 0.

[Consensus report: tissue handling in suspected Creutzfeldt-Jakob disease and other spongiform encephalopathies (prion diseases) in the human. European Union Biomed-1 Concerted Action].

Despite many sensational and intimidating reports in the mass media, transmissible spongiform encephalopathies (prion diseases) are not contagious in the usual sense. Successful transmission requires both specific material (an affected individual's tissue, from or adjacent to CNS) and specific modes (mainly penetrating contact with the recipient). Nevertheless, specific safety precautions are mandatory to avoid accidental transmission and to decontaminate any infectivity.

Proposed link between transmissible spongiform encephalopathies of man and animals.

A link between scrapie and Creutzfeldt-Jakob disease (CJD) is likely to exist. Based on old observations on scrapie, new experiments on bovine spongiform encephalopathy, and modern reviews on CJD, my proposal fits general rules of virus transmission.

Western blot mapping of disease-specific amyloid in various animal species and humans with transmissible spongiform encephalopathies using a high-yield purification method.

SAF-protein, an amyloid, is the main constituent of scrapie-associated fibrils (SAF) and a specific marker for transmissible spongiform encephalopathies (TSE). Using an improved extraction method and Western blot detection, the disease-specific amyloid was found in various parts of the central nervous system of hamsters orally infected with scrapie, of squirrel monkeys orally infected with kuru, sporadic Creutzfeldt-Jakob disease (CJD) and scrapie, of human patients with sporadic CJD, of a sheep with natural scrapie and of a cow with bovine spongiform encephalopathy (BSE). In human CJD samples, the concentration of TSE-specific amyloid was estimated to be 1000- to 10 000-fold lower than in the central nervous system of hamsters with scrapie.

Tissue handling in suspected Creutzfeldt-Jakob disease (CJD) and other human spongiform encephalopathies (prion diseases).

Despite many sensational and intimidating reports in the mass media, transmissible spongiform encephalopathies (prion disease) are not contagious in the usual sense. Successful transmission requires both specific material (an affected individual's tissue, from or adjacent to CNS) and specific modes (mainly penetrating contact with the recipient). Nevertheless, specific safety precautions are mandatory to avoid accidental transmission and to decontaminate any infectivity.

The original Gerstmann-Sträussler-Scheinker family of Austria: divergent clinicopathological phenotypes but constant PrP genotype.

We present new data on the original Austrian kindred with Gerstmann-Sträussler-Scheinker disease (GSS) which encompasses currently 221 members in 9 generations. The mode of inheritance is autosomal dominant. Predominant clinical features are slowly progressive ataxia and late impairment of higher cerebral functions.

Small virus-like structure in brains from cases of sporadic and familial Creutzfeldt-Jakob disease.

We have previously observed small virus-like particles in the brain of hamsters with experimental scrapie. Here we report that small virus-like structures can be isolated from brains of patients with Creutzfeldt-Jakob disease and identified by electronmicroscopy.

Bovine spongiform encephalopathy in Germany.

Bovine spongiform encephalopathy (BSE) has been described as an epidemic central nervous disorder in cattle from the United Kingdom. The disease is thought to have emerged by an interspecies transmission of the scrapie agent of sheep to cattle, after feeding scrapie-contaminated meat and bone meal (MBM). The disease has caused substantial economic losses for the British cattle industry.

Small virus-like structure in fractions from scrapie hamster brain.

The scrapie model in hamsters has been used to search for the agents that cause Creutzfeldt-Jakob disease in man and similar transmissible encephalopathies in animals. We found structures that are extraordinarily small for a virus, but exhibit viral structural properties in negatively stained samples, by electron microscopy in fractions containing scrapie-associated fibrils.

Characterisation of antisera raised against species-specific peptide sequences from scrapie-associated fibril protein and their application for post-mortem immunodiagnosis of spongiform encephalopathies.

Transmissible spongiform encephalopathies (TSE), such as scrapie or Creutzfeldt-Jakob disease (CJD), are fatal neurodegenerative diseases of the central nervous system caused by a yet unidentified virus. They are accompanied by a brain specific amyloidosis, during which a host coded protein irreversibly aggregates to form the scrapie-associated fibrils. The diagnosis of TSE relies on histopathological detection of spongiform lesions, on electron microscopical detection of fibrils, or on the immunological detection of SAF protein, which is the most specific diagnostic marker.