Publications

nmr structure of the mouse prion protein domain prp(121-321).	the 'protein only' hypothesis states that a modified form of normal prion protein triggers infectious neurodegenerative diseases, such as bovine spongiform encephalopathy (bse), or creutzfeldt-jakob disease (cjd) in humans. prion proteins are thought to exist in two different conformations: the 'benign' prpcform, and the infectious 'scrapie form', prpsc. knowledge of the three-dimensional structure of prpc is essential for understanding the transition to prpsc. the nuclear magnetic resonance (nm ...	1996	8700211
[creutzfeldt-jakob disease--a human prion disease].	the human prion diseases, creutzfeldt-jakob disease, gerstmann-strøaussler-scheinker syndrome and kuru, are neurodegenerative disorders sharing clinical features of rapidly progressive neurodegenerative dementia and cerebellar symptoms of marked ataxia and tremor, resulting in death within one year after onset. similar diseases have been described in animals, such as scrapie in sheep and goats, and bovine spongiform encephalopathy in cattle (mad cow disease). the very long incubation period, the ...	1996	8700643
[human spongiform encephalopathies. diseases caused by prions].	spongiform encephalopathies or prion diseases are common denominators for a group of diseases, all fatal, which show characteristic neuropathological changes. in man the group includes four diseases: kuru, creutzfeldt-jakob's disease (cjd), gerstmann-sträussler-scheinker's disease (gss) and fatal familial insomnia (ffi). in animals it comprises the following six: scrapie (sheep and goats), transmissible mink encephalopathy (mink), chronic wasting disease (mule/elk), exotic ungulate encephalopath ...	1996	8701521
opinion on possible ban on ruminant by-products in ruminant feeds.		1996	8707657
origin of bse.		1996	8711889
[psi] and [ure3] as yeast prions.	[ure3] is a non-mendelian genetic element that mimics recessive mutations in the chromosomal ure2 gene making cells derepressed for nitrogen catabolic enzymes. [psi] is a non-mendelian enhancer of readthrough of translational termination similar in its effects to some mutations in the chromosomal sup35 gene. three lines of evidence led to the proposal that both [ure3] and [psi] are prions, infectious proteins analogous to the scrapie agent mediating transmissible spongiform encephalopathies of m ...	1995	8720070
histopathological changes in the islets of langerhans in hamsters infected with the 139h strain of scrapie: semi-thin section study.	using histopathological analysis of semi-thin sections stained with toluidine blue, we observed profound pathological changes in the islets of langerhans of hamsters infected with the scrapie agent (strain 139h). these included cytoplasmic vesicles, nuclear swelling, and vacuolization in the islet cells. two types of vacuolization were seen. "localized vacuolization" (lv) has a distinct edge and is restricted or confined within the cell. "diffuse vacuolization" (dv) has no distinct edge and is s ...	1996	8720460
immunohistochemical detection of prion protein in lymphoid tissues of sheep with natural scrapie.	the scrapie-associated form of the prion protein (prpsc) accumulates in the brain and lymphoid tissues of sheep with scrapie. in order to assess whether detecting prpsc in lymphoid tissue could be used as a diagnostic test for scrapie, we studied the localization and distribution of prpsc in various lymphoid tissues collected at necropsy from 55 sheep with clinical scrapie. samples collected from the spleen, palatine tonsil, ileum, and five different lymph nodes were immunohistochemically staine ...	1996	8727908
ultrastructural immuno-localization of synthetic prion protein peptide antibodies in 87v murine scrapie.	disease specific forms of a host encoded cell surface sialoglycoprotein called prion protein (prp) accumulate during this incubation period of the transmissible spongiform encephalopathies. a 33-35 kda disease specific form of prp is partially resistant to protease digestion whereas the normal form of prp can be completely digested. proteinase k digestion of the murine disease specific form of prp produces diverse forms of low molecular weight prp, some of which are n-terminally truncated at ami ...	1996	8731389
the uk epidemic of bse: slow virus or chronic pesticide-initiated modification of the prion protein? part 2: an epidemiological perspective.	this paper elucidates the flaws in the official hypothesis that bovine spongioform encephalopathy originated from alterations in the way that scrapie-contaminated cattlefeeds were manufactured in the uk. an alternative hypothesis is proposed that cites exposure of the bovine embryo to various specific high-dose lipophilic formulations of organophosphates, such as the high-dose phthalimide containing organophosphate phosmet, (which were applied compulsorily and exclusively in the uk during the 19 ...	1996	8735882
mouse inoculation studies reveal no transmissible agent in amyotrophic lateral sclerosis.	amyotrophic lateral sclerosis (als) resembles the spongiform encephalopathies in its dual pattern of inherited and sporadic cases, its uniform prevalence in different populations, its late onset (suggestive of a long incubation period) and its pathological picture of neuronal degeneration without inflammation. there is a well-established protocol for primary transmission of scrapie and related diseases to mice. using this, we inoculated four longlived, inbred, mouse strains with cord material fr ...	1996	8737921
prion protein amyloidosis.	the prion protein (prp) plays an essential role in the pathogenesis of a group of sporadic, genetically determined and infectious fatal degenerative diseases, referred to as "prion diseases", affecting the central nervous system of humans and other mammals. the cellular prp is encoded by a single copy gene, highly conserved across mammalian species. in prion diseases, prp undergoes conformational changes involving a shift from alpha-helix to beta-sheet structure. this conversion is important for ...	1996	8737929
inactivation of the bovine spongiform encephalopathy agent by rendering procedures.	bovine brain infected with the bovine spongiform encephalopathy (bse) agent was used to spike material processed in pilot scale facsimiles of 12 rendering processes which are used within the european union, and three which are not. the raw materials for experimental rendering represented those used in practice, and consisted of appropriate proportions of bse-infected brain tissue, bovine or porcine intestine, and bovine bone. meat and bone meal, and tallow were produced from the rendered tissues ...	1995	8746849
scrapie in mice deficient in apolipoprotein e or glial fibrillary acidic protein.	in the prion diseases, extensive reactive gliosis is often found to be out of proportion to the degree of apparent neuronal damage. to evaluate the role of astrocytic gliosis in experimental scrapie of the mouse, we inoculated mice deficient in apolipoprotein e (apoe) or the glial fibrillary acidic protein (gfap) with mouse prions. the expression of both apoe and gfap in astrocytes increases as part of the reactive gliosis that accompanies scrapie. null mice deficient in either apoe or gfap inoc ...	1996	8757019
scrapie infection can be established readily through skin scarification in immunocompetent but not immunodeficient mice.	scarification of the skin is a possible route of entry for scrapie infectivity in sheep, and for creutzfeldt-jakob disease agent in humans within the context of occupational exposure to infected brain in the autopsy room or laboratory. the effectiveness of skin scarification routes as portals of entry for infectivity had not previously been tested experimentally but this study has shown that these are efficient routes for establishing infection in mice using the 139a and me7 strains of scrapie a ...	1996	8758004
strain specific and common pathogenic events in murine models of scrapie and bovine spongiform encephalopathy.	the development of transmissible spongiform encephalopathies in experimental models depends on two major factors: the intracerebral accumulation of an abnormal, protease-resistant isoform of prp (prpres), which is a host protein mainly expressed in neurons; and the existence of different strains of agent. in order to make a distinction between pathogenic mechanisms depending upon the accumulation of host-derived prpres and the strain-specific effects, we quantified and compared the sequence of m ...	1996	8758005
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 a ...	1996	8760444
replication of scrapie in spleens of scid mice follows reconstitution with wild-type mouse bone marrow.	scid mice are resistant to intraperitoneal infection with 10(3) and 10(4) intracerebral id50 units of me7 scrapie agent whereas they develop disease after intracerebral challenge. however, higher doses introduced, by intraperitoneal or subcutaneous routes, produce disease. immunocompetent mice of the same strain (cb20) developed scrapie following either intracerebral or intraperitoneal infection. bioassay of spleens from scid mice infected with 10(-1) dilutions of me7 scrapie by intraperitoneal, ...	1996	8760445
protease-resistant prp deposition in brain and non-central nervous system tissues of a murine model of bovine spongiform encephalopathy.	infectivity within the central nervous system has been demonstrated by the transmission of bovine spongiform encephalopathy (bse) from affected cattle to inbred laboratory mice. sedimentable, protease-resistant prp (prpsc) has also been extracted from bse-affected cattle brain. both infectivity and prpsc have been reported in the lymphoreticular tissues of sheep and mice clinically and preclinically affected with scrapie. neither infectivity nor prpsc has yet been detected in non-neural tissues ...	1996	8760446
histopathological changes in the pituitary glands of female hamsters infected with the 139h strain of scrapie.	previous studies in hamsters showed that the 139h strain of scrapie injected intracerebrally caused a generalized endocrinopathy and marked hypoglycaemia and hyperinsulinaemia. the low scrapie infectivity levels in the pancreas suggested that the changes noted in that organ were of neuroendocrine origin. in the current study, female weanling syrian hamsters were inoculated intracerebrally with scrapie strain 139h or 263k, or with homogenate of normal hamster brain. coronal sections of the pituit ...	1996	8762587
[id-dlo designs preclinical test for scrapie. the netherlands and england together fighting bse].		1996	8765805
pruritus in creutzfeldt-jakob disease.	we report three patients with creutzfeldt-jakob disease, whose first symptom was severe pruritus, similar to that observed in scrapie. the pruritus was resistant to therapy. the underlying mechanisms are unclear, but we speculate that the pruritus may result from brainstem involvement.	1996	8780068
molecular biology of brain aging and neurodegenerative disorders.	a significant component of the aging process is genetically determined. numerous theories of aging exist, many of which postulate the existence of "longevity genes." recent advances in molecular biological and other techniques have allowed a significantly greater understanding of aging and age-related disease. this will be illustrated by four genetic and sporadic diseases: alzheimer's disease (ad) and related disorders, transthyretin dementia, cerebral amyloid angiopathy-icelandic type and scrap ...	1996	8787186
high prion and prpsc levels but delayed onset of disease in scrapie-inoculated mice heterozygous for a disrupted prp gene.	it has been proposed that the prion, the infectious agent of transmissible spongiform encephalopathies, is prpsc, a post-translationally modified form of the normal host protein prpc. we showed previously that mice devoid of prpc (prn-p0/0) are completely resistant to scrapie. we now report on the unexpected response of heterozygous (prn-p0/+) mice to scrapie infection.	1994	8790598
observations on the transmission of scrapie in experiments using embryo transfer.	this investigation studied the maternal transmission of scrapie in sheep by using embryo transfer to examine the viability of highly susceptible offspring derived from scrapie-affected and uninfected donors. the study also examined the effect of washing the embryos. scrapie occurred in both washed and unwashed embryo-derived sip sasa progeny from both groups of donor ewes. as a result, the earlier observation that scrapie might pass via the unwashed embryo to develop as disease in adult sheep ha ...	1996	8795182
spongiform encephalopathies: still many unanswered questions.		1996	8795492
decreased receptor-mediated calcium response in prion-infected cells correlates with decreased membrane fluidity and ip3 release.	the most characteristic neuropathologic features of prion diseases are accumulation of prpsc in the brain and vacuolation of neurons. neuronal vacuolation suggests plasma membrane dysfunction. in an earlier study, we found that bradykinin (bk)-stimulated ca2+ responses in scrapie-infected scn2a cells were reduced by 30 to 50% compared with uninfected n2a cells. in this study, we investigated the cause. the ip3 second-messenger response to bk stimulation was reduced 90%, indicating that a defect ...	1996	8797473
improvements in a competition assay to detect scrapie prion protein by capillary electrophoresis.	scrapie in sheep and goats is the prototype of transmissible spongiform encephalopathies found in humans and animals. a feature of these diseases is the accumulation of rod-shaped fibrils in the brain that form from an aggregated protein. this protein is a protease-resistant form of a normal host cell protein. when the aggregated protein is denatured in sds and beta-mercaptoethanol, a monomer form (prion protein) with a molecular mass of 27 kda is observed. free zone capillary electrophoresis an ...	1996	8798909
visualization of viral candidate cdnas in infectious brain fractions from creutzfeldt-jakob disease by representational difference analysis.	creutzfeldt-jakob disease (cjd), a neurodegenerative and dementing disease of later life, is caused by a viruslike entity that is incompletely characterized. as in scrapie, all more purified infectious brain preparations contain nucleic acids. however, it has not been possible to visualize unique bands that may derive from a viral genome. we here used a subtractive strategy known as representational difference analysis (rda) to uncover such sequences. to reduce the complexity of starting target ...	1996	8799215
the response of the 22a strain of scrapie agent to microwave irradiation compared with boiling.	the 22a strain of scrapie agent was exposed to boiling or microwave irradiation. subsequent bioassay in im and vm mice showed that neither treatment had inactivated the agent. although im and vm mice are homozygous for the p7 allele of the sinc gene which controls the incubation period of scrapie in mice, the incubation period for unheated 22a was 22 days longer in im compared with vm mice. this suggests that other unidentified genes can have a more minor effect on incubation period. the differe ...	1996	8804028
spatial reversal learning in preclinical scrapie-inoculated mice.	acquisition and reversal of a two-choice spatial discrimination were tested in scrapie-inoculated mice. both acquisition and reversal were normal in mice tested 138 and 103 days prior to the onset of clinical symptoms. at 65 days before onset of clinical symptoms, scrapie-inoculated mice required more trails to criterion in reversal learning, but this effect was not significant in a second experiment (68 days preclinical) and was transient: no effect was seen 33 days before symptoms. however, th ...	1996	8804057
immunoreactivity of specific epitopes of prpsc is enhanced by pretreatment in a hydrated autoclave.	an abnormal protein (prpsc) accumulates in animals affected with scrapie. immunoblotting procedures have been used widely to detect prpsc. blotted membranes were subjected to pretreatment in a hydrated autoclave, and the subsequent immunoreactivity of prpsc was examined. the immunoreactivity of prpsc to antisera against the synthetic peptides of the mouse prp amino acid sequences 199 to 208 and 213 to 226 was enhanced by the pretreatment. however, the reactivity to antisera of peptide sequences ...	1996	8807215
aggregates of scrapie-associated prion protein induce the cell-free conversion of protease-sensitive prion protein to the protease-resistant state.	scrapie infection instigates the in vivo conversion of normal, protease-sensitive prion protein (prpc) into a protease-resistant form (prpsc) by an unknown mechanism. in vitro studies have indicated that prpsc can induce this conversion, consistent with proposals that prpsc itself might be the infectious scrapie agent. using this cell-free model of the prpc to prpsc conversion, we have studied the dependence of conversion on reactant concentration, and the properties of the prpsc-derived species ...	1995	8807814
electrophoretic analysis of nucleic acids isolated from scrapie-infected hamster brain.	the purpose of this study was to investigate previous reports of a scrapie-specific 1.2 kb single-stranded dna observed in alkaline agarose electrophoresis gels. protocols were developed to be as consistent as possible with those used previously. partial subcellular fractionation was applied to the brains of hamsters clinically affected by the 263k strain of scrapie. nucleic acids were then isolated, and compared electrophoretically to nucleic acids isolated from equivalent fractions, made from ...	1996	8811040
the m22 antibody identifies highly activated reactive astrocytes responding to central nervous system disease.	astrocytes respond vigorously to diverse neurological insults. it is still not clear, however, whether this response is stereotypic following different insults or varies according to the injury. we have used a novel immunocytochemical marker of reactive astrocytes, termed m22, together with antibodies to glial fibrillary acidic protein (gfap), to analyze region- and insult-specific differences in reactive astrocytosis in the murine central nervous system (cns). pathology was variously induced by ...	1996	8834543
differential effects of a new amphotericin b derivative, ms-8209, on mouse bse and scrapie: implications for the mechanism of action of polyene antibiotics.	mice were infected intracerebrally with the bovine spongiform encephalopathy (bse) or the scrapie agent and treated during 8 weeks postinfection to test the protective effect of a new amphotericin b (amb) derivative, ms-8209, in experimental transmissible spongiform encephalopathies. the results show that (i) the treatment prolonged the incubation period of both bse-infected and scrapie-infected mice, (ii) ms-8209 and amb were much more efficient in delaying the onset of scrapie than that of bse ...	1996	8837228
evidence for an early inflammatory response in the central nervous system of mice with scrapie.	in alzheimer's disease, the most prevalent of the neurodegenerative diseases, inflammation of the cns contributes to the pathology and is a target for therapy. in contrast, the group of neurodegenerative conditions known as the prion diseases have been widely reported as lacking any inflammatory elements despite the many similarities between the pathologies of alzheimer's disease and prion diseases we have found evidence for an inflammatory component in mouse scrapie, characterized by microglial ...	1996	8843071
patch-clamp analysis of synaptic transmission to cerebellar purkinje cells of prion protein knockout mice.	the prion protein (prp) plays a pivotal role in transmissible spongiform encephalopathies such as creutzfeldt-jakob disease in humans and scrapie and bovine spongiform encephalopathy in animals. previous experiments have suggested that the normal cellular prion protein (prpc) is involved in synaptic function in the hippocampus. here, we utilized the controlled recording conditions of the patch-clamp technique to investigate the synaptic function of prion protein in cerebellar purkinje cells. by ...	1995	8845956
separating the environmental and genetic factors that may be causes of bovine spongiform encephalopathy.	the initial cause of the bovine spongiform encephalopathy (bse) epidemic is generally accepted to have been the feeding of infected animal protein to cattle. the proportion of animals affected in any year in a particular herd has generally been low. this suggests either considerable variation in the extent of challenge of the individual animals or variation in their susceptibility to challenge or both. there is known to be genetic variation in susceptibility in other spongiform encephalopathies, ...	1996	8856808
endosome-lysosomes, ubiquitin and neurodegeneration.	before the advent of ubiquitin immunochemistry and immunogold electron microscopy, there was no known intracellular molecular commonality between neurodegenerative diseases. the application of antibodies which primarily detect ubiquitin protein conjugates has shown that all of the human and animal idiopathic and transmissible chronic neurodegenerative diseases, (including alzheimer's disease (ad), lewy body disease (lbd), amyotrophic lateral sclerosis (als), creutzfeldt-jakob disease (cjd) and s ...	1996	8861020
mad cow disease and creutzfeldt-jakob disease--is there a link?	the report of the creutzfeldt-jakob surveillance unit from march 1996 regarding 10 cases of a new variant of creutzfeldt-jakob disease (cjd) in young adults caused a great deal of uproar when it was suggested that a possible link with bovine spongiform encephalopathy (bse) could not be excluded. bse was first noticed in 1986 after the introduction of modified rendering systems in the manufacture of meat and bone meal containing animal wastes contaminated with scraple-like agents. this article re ...	1996	8863351
how do neurons degenerate in transmissible spongiform encephalopathies?	neuroaxonal dystrophy is a feature of neuronal degeneration encountered in all subacute spongiform virus encephalopathies including scrapie and creutzfeldt-jakob disease (cjd). by immunohistochemical techniques, the accumulation of 200 kda neurofilament protein was demonstrated in affected neurites in human cjd. these neurites exhibited the ultrastructural features of dystrophic neurites encountered in other neurodegenerative disorders, particularly alzheimer's disease. these findings support th ...	1996	8871966
partial unfolding and refolding of scrapie-associated prion protein: evidence for a critical 16-kda c-terminal domain.	the conversion of the normal form of prion protein (prpc) to a disease-specific form (prpsc) is a central event in scrapie and other transmissible spongiform encephalopathies. prpsc is distinguished from prpc by its insolubility and its resistance to proteolysis. prpsc is also capable of converting 35s-prpc, in vitro, into a form which is indistinguishable from prpsc with respect to its protease-sensitivity. both the "converting activity" and the protease-resistance of isolated hamster prpsc can ...	1996	8873612
analysis of prpc mrna by in situ hybridization in brain, placenta, uterus and testis of rats.	an amyloid-like isoform of a 33- to 34-kd glycoprotein, termed as the scrapie prion protein (prpsc), plays a critical role in transmissible spongiform encephalopathies of animals and humans. it has even been suggested to present the responsible infectious agent. this protein is a posttranslationally modified form of the cellular isoform of prion protein (prpc). hitherto, little has been known about the functions of prpc. in order to examine the localization of prpc mrna in rat tissues, the in si ...	1995	8880380
infectivity in extraneural tissues following intraocular scrapie infection.	intraocular (i.o.) infection of mice with scrapie produces strain-specific targeting of replication and subsequent pathology within the visual system projection areas in the cns, but also initiates an extraneural infection. following i.o. infection with me7 scrapie, infectivity was detected 24 h later in the harderian gland, the superficial cervical lymph nodes (sclns) and the spleen, but not until 20 days in peyer's patches and inguinal lymph nodes (ilns). persistent low levels of infectivity w ...	1996	8887504
prp genotype contributes to determining survival times of sheep with natural scrapie.	several allelic variants of the sheep prp gene are associated with scrapie susceptibility. however, it is not known whether, and to what extent, the prp genotype contributes to determining survival times of scrapie sheep. we therefore determined the prp genotype and life spans of over 50 flemish and swifter sheep within a single scrapie-affected flock. eighty-three per cent of the scrapie sheep were homozygous for the prp(vq) allele (polymorphic amino acids at codons 136 and 171 are indicated) a ...	1996	8887505
reduction of the infectivity of scrapie agent as a model for bse in the manufacturing process of trasylol.	the trasylol manufacturing process was investigated with respect to its capacity for the inactivation/removal of infectivity causing bovine spongiform encephalopathy (bse). four process steps were selected for this investigation and scaled down to laboratory scale. authentic samples of bovine lungs used in the trasylol manufacturing plant were taken and spiked in laboratory scale experiments with high infectious titres of the rodent adapted scrapie strain me 7 which served as model for bse. afte ...	1996	8889056
a neurotoxic prion protein fragment enhances proliferation of microglia but not astrocytes in culture.	the scrapie isoform of the prion protein (prpsc) induces pathological changes in the central nervous system including neurodegeneration and gliosis. a synthetic prion protein (prp) peptide corresponding to amino acid residues 106-126 has been shown to be toxic to neurons that express prpc, the cellular isoform of prp. here we show that in mixed glial cultures prp106-126 induces astroglial proliferation that is dependent on cellular prpc expression. in purified cultures of glial subtypes only mic ...	1996	8891692
no maternal transmission?		1996	8900261
aberrant induction of neuropeptide y mrna in hippocampal ca3 pyramidal neurones in scrapie-infected mice.	the neurochemical alterations preceding neurological dysfunction and neuronal death in prion diseases are not well characterized. here we examined, using in situ hybridization histochemistry, the expression of neuropeptide y (npy), an inducible and abundant neuropeptide in mammalian brain with known neuroregulatory functions, and glial fibrillary acidic protein (gfap), a marker for astroglial activation, in the hippocampus at different time points following intracerebral prion inoculation in mal ...	1996	8905686
comparison of biochemical extraction techniques for the detection of scrapie-associated fibrils in the central nervous system of sheep naturally affected with scrapie.	standardized samples of brain material from four sheep naturally affected with scrapie and from four healthy control sheep were subjected to six different extraction techniques used for the detection of scrapie-associated fibrils by negative-contrast transmission electron microscopy. the six methods were compared in respect of fibril yield and clarity of ultrastructure. the simplest method consisting of a single n-lauroylsarcosine detergent extraction and differential centrifugation, followed by ...	1996	8910745
prion protein amyloid: separation of scrapie infectivity from prp polymers.	the prion protein (prp) undergoes a profound conformational change when the cellular isoform (prpc) is converted into the scrapie form (prpsc). limited proteolysis of prpsc produces prp27-30 which readily polymerizes into amyloid. to study the structure of prp amyloid, we employed organic solvents that perturb protein conformation. 1,1,1,3,3,3-hexafluoro-2-propanol (hfip), which promotes alpha-helix formation, modified the ultrastructure of rod-shaped prp amyloids, producing flattened ribbons wi ...	1996	8915611
normal host prion protein (prpc) is required for scrapie spread within the central nervous system.	mice devoid of prpc (prnp%) are resistant to scrapie and do not allow propagation of the infectious agent (prion). prpc-expressing neuroectodermal tissue grafted into prnp% brains but not the surrounding tissue consistently exhibits scrapie-specific pathology and allows prion replication after inoculation. scrapie prions administered intraocularly into wild-type mice spread efficiently to the central nervous system within 16 weeks. to determine whether prpc is required for scrapie spread, we ino ...	1996	8917559
margination and diapedesis of inflammatory cells in the islets of langerhans in hamsters infected with the 139h strain of scrapie.	the islets of langerhans in hamsters infected with the 139h strain of scrapie contain large masses of red blood cells not surrounded by the usual arterial, venous or capillary wall cells. we have referred to these structures as "blood vessel cores" (bvcs). bvcs were almost always centrally located within the islets and surrounded by pancreatic b cells. margination and diapedesis of inflammatory cells were observed at the bvc walls in 139h-infected hamsters. the cells consisted of the following t ...	1996	8920215
improvement of prpsc-detection in mouse spleen early at the preclinical stage of scrapie with collagenase-completed tissue homogenization and sarkosyl-nacl extraction of prpsc.	scrapie in sheep has recently become again a target of control measures and eradication programs. crucial for the effectiveness of these measures is the detection of infected sheep during the long and potentially hazardous incubation period. however, routine-diagnosis is mostly limited to clinical examinations when disease becomes apparent, and to postmortem investigations. through the detection of the scrapie-specific isoform of the prion protein (prpsc) by western blot in the spleen and lymph ...	1996	8920821
intracellular calcium rise through l-type calcium channels, as molecular mechanism for prion protein fragment 106-126-induced astroglial proliferation.	the infectious prion protein (prpsc) is the etiologic agent of transmissible neurodegenerative conditions such as scrapie or creutzfeldt-jakob disease. its fragment 106-126 (prp106-126) has been reported to maintain most of the pathological features of prpsc. we report here the intracellular mechanisms mediating the proliferative effects of prp106-126 on rat cortical type i astrocytes. the proliferative effects of prp106-126 started after 24h of treatment and lasted up to 9 days and was antagoni ...	1996	8920926
novel polymorphisms in the caprine prp gene: a codon 142 mutation associated with scrapie incubation period.	age at disease onset and rate of progression of transmissible spongiform encephalopathies in man, sheep and mice are modulated by the host genome, in particular by the prp gene and its allelic forms. analysis of the caprine prp gene revealed several different alleles. four prp protein variants were found, three of which were goat specific with single amino acid changes at codons 142, 143 and 240. the fourth was identical to the most common sheep prp protein variant (ala136-arg154-gln171). the di ...	1996	8922485
polymorphism at codon 129 of the prion protein gene determines cerebellar pathology in creutzfeldt-jakob disease.	creutzfeldt-jakob disease (cjd) is a transmissible neurodegenerative disorder characterized by the accumulation of proteinase-resistant prion protein (prp) in the brain. pathological changes in the cerebellum are common and include atrophy of the granular layer, spongiform change in the molecular layer, and astrocytic gliosis of the cerebellar cortex and white matter. in most cases of sporadic cjd immunohistochemistry for prp shows widespread granular deposits of the scrapie isoform of the prion ...	1996	8937783
scrapie: recent trends.		1996	8941420
how many phenotypes from one genotype? the case of prion diseases.	the usual assumption, namely that the underlying biochemical reactions in an organism tend to a unique steady-state, is shown to be not always correct. there are certain pathway mechanisms (e.g. positive feedback) which allow the system to exists in two alternative stable steady states. this bistability implies that environmental perturbations can "switch" the system from either state to the other. such a switch takes place at the metabolic level and hence a single genotype can display two diffe ...	1996	8944151
immunolocalisation of the prion protein (prp) in the brains of sheep with scrapie.	cheviot sheep from the neuropathogenesis unit flock were examined for prp in brain sections using immunocytochemistry in order to aid scrapie diagnosis. brains were collected from sheep which had been naturally or experimentally infected with scrapie and fixed in periodate-lysine-paraformaldehyde or in formalin. immunolabelling was achieved using a monoclonal antibody (fh11) raised to the n-terminus of recombinant prp protein. several pre-treatments were studied in an effort to enhance prp immun ...	1996	8953691
sleep, genes and death: fatal familial insomnia.	over the past 30 years, significant progress has been made in understanding the physiologic mechanisms of sleep. insomnia, a common complaint in general medical practice, and other sleep disorders have become increasingly recognized. in 1986, a heritable total insomnia was described and termed fatal familial insomnia; since then, the pathology of this disease has been shown to involve an accumulation of prion particles in the brains of affected patients. prions have been more commonly associated ...	1996	8957563
subcellular colocalization of the cellular and scrapie prion proteins in caveolae-like membranous domains.	results of transgenetic studies argue that the scrapie isoform of the prion protein (prpsc) interacts with the substrate cellular prp (prpc) during conversion into nascent prpsc. while prpsc appears to accumulate primarily in lysosomes, caveolae-like domains (clds) have been suggested to be the site where prpc is converted into prpsc. we report herein that clds isolated from scrapie-infected neuroblastoma (scn2a) cells contain prpc and prpsc. after lysis of scn2a cells in ice-cold triton x-100, ...	1996	8962161
[several problems concerning bovine spongiform encephalopathy].		1996	8965331
[studies on prion diseases].		1996	8966477
eu stops fiddling while cows burn.		1996	8966596
activation effects of a prion protein fragment [prp-(106-126)] on human leucocytes.	prion-related encephalopathies are characterized by the intracerebral accumulation of an abnormal isoform of the cellular prion protein (prpc) named scrapie prion protein (prpsc). the pathological forms of this protein and its cellular precursor are not only expressed in the brain but also, at lower concentrations, in peripheral tissues. we recently showed that a synthetic peptide corresponding to residues 106-126 [prp-(106-126)] of the human prp is toxic to neurons and trophic to astrocytes in ...	1996	8973567
neuropathological diagnostic criteria for creutzfeldt-jakob disease (cjd) and other human spongiform encephalopathies (prion diseases).	neuropathological diagnostic criteria for creutzfeldt-jakob disease (cjd) and other human transmissible spongiform encephalopathies (prion diseases) are proposed for the following disease entities: cjd--sporadic, iatrogenic (recognised risk) or familial (same disease in 1st degree relative): spongiform encephalopathy in cerebral and/or cerebellar cortex and/or subcortical grey matter; or encephalopathy with prion protein (prp) immunoreactivity (plaque and/or diffuse synaptic and/or patchy/periva ...	1995	8974629
chemical chaperones interfere with the formation of scrapie prion protein.	the fundamental event in prion diseases involves a conformational change in one or more of the alpha-helices of the cellular prion protein (prp(c)) as they are converted into beta-sheets during the formation of the pathogenic isoform (prp(sc)). here, we show that exposure of scrapie-infected mouse neuroblastoma (scn2a) cells to reagents known to stabilize proteins in their native conformation reduced the rate and extent of prp(sc) formation. such reagents include the cellular osmolytes glycerol ...	1996	8978663
detection of scrapie agent in the peripheral nervous system of a diseased sheep.	in an attempt to determine whether scrapie infectivity can be found in the peripheral nervous system of a scrapie-diseased sheep, mice were inoculated intracerebrally or intraperitoneally with 10-fold dilutions of homogenates of nervus (n.) axillaris, n. ulnaris, n. medianus, n. ischiadicus, n. tibialis, n. fibularis, and n.saphenus. mice were observed for clinical signs of scrapie for 700 days and their brains were analyzed for accumulation of pathological prion protein by immunoblot. substanti ...	1996	8980019
recombinant scrapie-like prion protein of 106 amino acids is soluble.	the n terminus of the scrapie isoform of prion protein (prpsc) can be truncated without loss of scrapie infectivity and, correspondingly, the truncation of the n terminus of the cellular isoform, prpc, still permits conversion into prpsc. to assess whether additional segments of the prp molecule can be deleted, we previously removed regions of putative secondary structure in prpc; in the present study we found that deletion of each of the four predicted helices prevented prpsc formation, as did ...	1996	8986833
direct conversion of an oligopeptide from a beta-sheet to an alpha-helix: a model for amyloid formation.	a 16-amino acid oligopeptide forms a stable beta-sheet structure in water. in physiological solutions it is able to self-assemble to form a macroscopic matrix that stains with congo red. on raising the temperature of the aqueous solution above 70 degrees c, an abrupt structural transition occurs in the cd spectra from a beta-sheet to a stable alpha-helix without a detectable random-coil intermediate. with cooling, it retained the alpha-helical form and took several weeks at room temperature to p ...	1997	8990154
[bovine spongiform encephalopathy. second update of data collected since the report of february 6, 1996].	the observation in 1995 and 1996 of 12 cases of a new variant of creutzfeldt-jakob disease (v-cjd) in u.k. suggested a possible relation between this human cases and bovine spongiform encephalopathy (bse). recent papers about this topic are reviewed: bse transmission to macaques, transmission of scrapie with embryo transfer, incidence of maternal transmission, prp protein released by platelets, diagnostic test by detection of prp protein in tissues of sheep, epidemiology of bse, french regulatio ...	1996	8991617
the effect of dry heat on the me7 strain of mouse-passaged scrapie agent.	partial survival of lyophilized scrapie agent has been reported previously following exposure to dry heat at 360 degrees c for 1 h, and led to speculation that scrapie-like agents might not be completely inactivated by incineration. however, it is known that dried infectivity is more difficult to inactivate by heat than that in hydrated samples. in this present study it was shown that the infectivity in macerates of mouse-brain infected with the me7 strain of scrapie agent was not completely ina ...	1996	9000112
scrapie strains retain their distinctive characteristics following passages of homogenates from different brain regions and spleen.	the molecular basis of differences among scrapie strains is unknown. the prion theory posits that there are differences in the conformation of the host protease-resistant protein (prp) molecules and that these differences are responsible for scrapie strains. a corollary of this theory is that the origin of host prp variation resides in different neuronal cell types. to assess this concept, preparations from three brain regions (cerebrum, cerebellum and olfactory bulb) and from spleen were passag ...	1997	9010315
characterisation of two promoters for prion protein (prp) gene expression in neuronal cells.	the neuronal membrane protein, prp, has a key role in the development of the transmissible spongiform encephalopathies and the level of expression of the prp gene has been shown to affect the disease profile. in order to define the sequences that are responsible for the normal expression of the prp gene we have isolated and sequenced a 5' region of the murine prp gene, which includes 1.2 kb upstream from exon 1, intron i and exon 2. sequencing of this region from several strains of mice identifi ...	1997	9016962
association between natural scrapie and prp genotype in a flock of suffolk sheep in scotland.	the incidence of natural scrapie in sheep is associated with polymorphisms of the prp gene, particularly those at codons 136, 154 and 171. in many breeds, the prp allele encoding valine at codon 136 confers an extremely high risk of scrapie, but in suffolk sheep this allele is vanishingly rare. in this study of a single closed flock of suffolk sheep in scotland, scrapie occurred primarily in animals which were homozygous for glutamine at codon 171, a genotype which was significantly less frequen ...	1997	9023905
a review of the epidemiology of scrapie in sheep.	the aim of this review is to summarise and evaluate the data available about the aetiology of scrapie in naturally affected sheep flocks, particularly data concerning the possible transmission of infection between related animals. the author examines data taken from various relevant studies carried out over the last thirty years. the main conclusions are that scrapie is an infectious disease with a genetic influence on the incubation period. the increased risk of disease in the offspring of affe ...	1996	9025137
bovine spongiform encephalopathy: an update.	a specialist group of the office international des epizooties met in may 1996 to prepare updated information on bovine spongiform encephalopathy (bse): in particular on the development of the epidemic, geographical incidence, nature of the disease, transmission, precautions and control measures. a revised chapter 3.2.13. of the international animal health code dealing with bse, and an outline of the spongiform encephalopathies, are appended, along with a comprehensive bibliography.	1996	9025153
spongiform encephalopathy in free-ranging mule deer (odocoileus hemionus), white-tailed deer (odocoileus virginianus) and rocky mountain elk (cervus elaphus nelsoni) in northcentral colorado.	between march 1981 and june 1995, a neurological disease characterized histologically by spongiform encephalopathy was diagnosed in 49 free-ranging cervids from northcentral colorado (usa). mule deer (odocoileus hemionus) were the primary species affected and accounted for 41 (84%) of the 49 cases, but six rocky mountain elk (cervus elaphus nelsoni) and two white-tailed deer (odocoileus virginianus) were also affected. clinical signs included emaciation, excessive salivation, behavioral changes, ...	1997	9027685
characterization of a prion protein (prp) gene from rabbit; a species with apparent resistance to infection by prions.	the prion protein gene (prp) encodes a cellular protein of unknown function. a conformational isoform of this protein is involved in the neurodegenerative prion diseases. to facilitate the identification of structurally and antigenically important regions within the prp molecule, the rabbit prp open reading frame (orf) was cloned and characterised. there is 82-87% identity at the nucleotide sequence level and 88-93% identity at the amino acid (aa) sequence level, between the rabbit gene and prp ...	1997	9031631
failure to transmit disease from gray tremor mutant mice.	mice homozygous for mutant alleles at the gray tremor (gt) locus develop a marked non-intention tremor beginning at 8 days of age. most homozygous mice die by 3 months. homozygotes exhibit intense vacuolation of the central nervous system gray matter and vacuolation and hypomyelination of some white matter tracts. based on neuropathological similarities with scrapie, other investigators inoculated wild-type mice with gray tremor brain homogenates to test the hypothesis of transmissibility. publi ...	1997	9032370
characterization of detergent-insoluble complexes containing the cellular prion protein and its scrapie isoform.	cells infected with prions contain both prion protein isoforms cellular prion protein (prpc) and scrapie prion protein (prpsc). prpsc is formed posttranslationally through the pathological refolding of prpc. in scrapie-infected scn2a cells, the metabolism of both prp isoforms involves cholesterol-dependent pathways. we show here that both prpc and prpsc are attached to triton x-100-insoluble, low-density complexes or "rafts." these complexes are sensitive to saponin and thus probably contain cho ...	1997	9045652
neuropathology of scrapie: a study of the distribution patterns of brain lesions in 222 cases of natural scrapie in sheep, 1982-1991.	detailed neuropathological findings in 222 cases of naturally occurring scrapie from great britain are described. the material consisted of formalin-fixed brain from eight breeds of sheep submitted between 1982 and 1991. paraffin-embedded histological sections were made from several specified brain areas, including the medulla oblongata, cerebellum, pons, mesencephalon, diencephalon, septal area, basal ganglia and frontal cortex. sections were examined by conventional and polarised light microsc ...	1997	9055393
bse: a decade on--part i.	bovine spongiform encephalopathy (bse), popularly known as "mad cow disease", was discovered in 1986 and has accounted for the deaths of over 165,000 cattle in the uk (by the end of january, 1997) with about 34,000 (mainly dairy) herds involved. the syndrome in the cow includes changes in posture and temperament, apprehension, and loss of coordination. there are many parallels with scraple in sheep, with similar neuropathological changes in the hindbrain that give it a spongiform appearance unde ...	1997	9057745
is scrapie solely a genetic disease?		1997	9062185
[a new variant of creutzfeldt-jakob disease. do we want development of a new epidemic?].	human spongiform encephalopathies have been receiving a lot of attention lately, because of a new variant of creutzfeldt-jakob disease and its possible connection to bovine spongiform encephalopathy which has reached epidemic proportions in great britain during the last ten years. four different human spongiform encephalopathies have been described, the most common being creutzfeldt-jakob disease, which can occur in a sporadic, familial or transmissible form. the infectious agent is mainly, poss ...	1997	9064863
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 necessit ...	1997	9078212
scrapie prions: a three-dimensional model of an infectious fragment.	a conformational change seems to represent the major difference between the scrapie prion protein (prpsc) and its normal cellular isoform (prpc). we recently proposed a set of four helix bundle models for the three-dimensional structure of prpc that are consistent with a variety of spectroscopic and genetic data.	1996	9079359
sensitive enzyme-linked immunosorbent assay for detection of prp(sc) in crude tissue extracts from scrapie-affected mice.	an enzyme-linked immunosorbent assay (elisa) was developed that detects prp(sc) in crude extracts from brain and spleen tissue of scrapie-affected mice with high sensitivity and specificity. brain tissue was homogenized in 8% zwittergent 3-12 and 0.5% sarkosyl. the homogenate was treated with collagenase and dnase i and then subjected to proteinase k digestion. precipitates containing prp(sc) were obtained by ultracentrifugation. spleen tissue was homogenized in 4% triton x-100 and 0.5% sarkosyl ...	1997	9079766
tubulovesicular structures are not labeled using antibodies to prion protein (prp) with the immunogold electron microscopy techniques.	tubulovesicular structures (tvs) are disease-specific, intraneuronal particles found by thin-section electron microscopy in all of the transmissible spongiform encephalopathies. we used immunogold (both 10 nm immunogold and 1 nm immunogold silver enhanced) methods for ultrastructural localization of prion protein (prp). in all scrapie models examined (263 k and 22ch in hamsters and 87v and me7 in mice), tvs-containing processes were readily detected but neither these processes nor tvs themselves ...	1997	9083557
scrapie infectivity correlates with converting activity, protease resistance, and aggregation of scrapie-associated prion protein in guanidine denaturation studies.	denaturation studies with guanidine hcl (gdnhcl) were performed to test the relationship between scrapie infectivity and properties of scrapie-associated prion protein (prp(sc)). large gdnhcl-induced reductions in infectivity were associated with the irreversible elimination of both the proteinase k resistance and apparent self-propagating converting activity of prp(sc). in intermediate gdnhcl concentrations that stimulate converting activity and partially disaggregate prp(sc), both scrapie infe ...	1997	9094691
scrapie infection alters the membrane and synaptic properties of mouse hippocampal ca1 pyramidal neurones.	1. electrophysiological recordings using conventional intracellular and extracellular techniques were made from the ca1 region of the hippocampus of me7 scrapie-infected mice in a brain slice preparation at specific stages during the incubation period of the disease and compared with data obtained from age-matched control animals. 2. extracellular field epsp recordings in the stratum radiatum showed a gradual increase in the effective stimulus threshold and a reduction in amplitude of the respon ...	1997	9097928
a novel hamster prion protein mrna contains an extra exon: increased expression in scrapie.	prion protein (prp) is the only known constituent of the agents (called prions) that cause fatal neurodegenerative diseases in animals and humans. prp derives from a host protein encoded by a single copy gene having three known exons in mice, cattle and sheep but only two exons in hamsters and humans. we have identified and sequenced the missing exon from the hamster prp gene. the new hamster prp exon is 83% identical to mouse exon 2 and 76% identical to exon 2 from cattle and sheep. prp mrnas c ...	1997	9099814
identification of intermediate steps in the conversion of a mutant prion protein to a scrapie-like form in cultured cells.	the central causative event in infectious, familial, and sporadic forms of prion disease is thought to be a conformational change that converts the cellular isoform of the prion protein (prpc) into the scrapie isoform (prpsc) that is the primary constituent of infectious prion particles. to provide a model system for analyzing the mechanistic details of this critical transformation, we have previously prepared cultured chinese hamster ovary cells that stably express mouse prp molecules carrying ...	1997	9111077
immunocytochemical evaluation of blood-brain barrier to endogenous albumin in scrapie-infected mice.	a quantitative immunocytochemical procedure was used for evaluation of the blood-brain barrier (bbb) to endogenous albumin in plaque-forming (pf) and non-plaque-forming (npf) groups of scrapie-infected mice at the clinical stage of disease. ultrathin sections of brain samples (cerebral cortex, hippocampus and cerebellum) embedded in resin (lowicryl k4m) were exposed to anti-mouse albumin antiserum followed by protein a-gold. using morphometry, the density of immunosignals (gold particles per mic ...	1997	9113199
transmissible encephalopathies and biopharmaceutical production.	the use of post-mortem tissues as sources for the production of biologicals, vaccines and feedstuffs has led to the transmission or generation of transmissible encephalopathies in some recipients. for example, the use of pituitary-derived human growth hormone and gonadotropins has resulted in the transmission of creutzfeldt-jakob disease to other humans [1], the use of formalin-inactivated sheep brain as a source for louping ill vaccine led to the transmission of scrapie to over 1,000 sheep from ...	1996	9119144
analysis of risk to biomedical products developed from animal sources (with special emphasis on the spongiform encephalopathy agents, scrapie and bse).	factors that must be considered in estimations of risk from exposure to adventitious contaminants of animal derived biologicals include: (i) the use of the product; (ii) the routes of administration and exposure to potential pathogens; (iii) the source of animal(s) and their history and maintenance; (iv) the tissue(s) used in the product and their likelihood of harbouring or being contaminated by an agent; (v) the methods by which the animal is slaughtered and the tissue(s) collected; (vi) the p ...	1996	9119146
transmissible spongiform encephalopathies (tse): minimizing the risk of transmission by biological/biopharmaceutical products: an industry perspective.	several guidelines and recommendations have been published on assessing the potential risk of a biological product being contaminated with an agent causing a transmissible spongiform encephalopathy (tse). basic principles which can be used during the manufacturing of biological products to minimize the risk of transmission of tse agents include the following: (i) obtaining animals, tissues or animal-derived raw materials from countries in which the relevant tse agent is reported to be absent; (i ...	1996	9119148
minimization of viral contamination in human pharmaceuticals produced in the milk of transgenic goats.	the minimization of viral contamination in therapeutic proteins produced in transgenic goats' milk can be achieved by a combinatorial approach. it begins with reduction in the risk in the starting material followed by appropriate clearance/inactivation steps in the purification process. to minimize risk in the starting material, genzyme transgenics corporation (gtc)'s closed goat herds are subjected to routine serological surveillance for known viral diseases, especially those transmitted throug ...	1996	9119149